POWER QUALITY PROBLEMS IN INDUSTRIAL ENTERPRISES AND …

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Power Systems Engineering Thesis

2020

POWER QUALITY PROBLEMS IN

INDUSTRIAL ENTERPRISES AND

THEIR MITIGATION TECHNIQUES

(CASE STUDY IN AMHARA PLASTIC

PIPE FACTORY)

TSEGAYE, FIREW

http://hdl.handle.net/123456789/11695

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BAHIR DAR UNIVERSITY

BAHIR DAR INSTITUTE OF TECHNOLOGY (BiT)

SCHOOL OF RESEARCH AND POSTGRADUATE STUDIES

FACULTY OF ELECTRICAL AND COMPUTER ENGINEERING

POWER QUALITY PROBLEMS IN INDUSTRIAL ENTERPRISES

AND THEIR MITIGATION TECHNIQUES

(CASE STUDY IN AMHARA PLASTIC PIPE FACTORY)

By

FIREW TSEGAYE SISAY

ADVISOR: DR.-ING. BELACHEW BANTYIRGA

Bahir Dar, Ethiopia

July 21, 2020

POWER QUALITY PROBLEMS IN INDUSTRIAL ENTERPRISES AND THEIR

MITIGATION TECHNIQUES

BY

FIREW TSEGAYE SISAY

A thesis submitted to the school of Research and Graduate Studies of Bahir Dar Institute

of Technology, BDU in partial fulfillment of the requirements for the degree of master in

the power system engineering in the faculty of electrical and computer engineering

Advisor:

Dr.-Ing. BELACHEW BANTYIRGA

Bahir Dar, Ethiopia

July 21, 2020

POWER QUALITY PROBLEMS IN INDUSTRIAL ENTERPRISES AND THEIR MITIGATION TECHNIQUES

MSc. Thesis By Firew Tsegaye/Power System Engineering/BIT/BDU Page i

DECLARATION

I, the undersigned, declare that the thesis comprises my own work. In compliance

with internationally accepted practices, I have acknowledged and refereed all

materials used in this work. I understand that non-adherence to the principles of

academic honesty and integrity, misrepresentation/ fabrication of any

idea/data/fact/source will constitute sufficient ground for disciplinary action by the

University and can also evoke penal action from the sources which have not been

properly cited or acknowledged.

Name of the student: Firew Tsegaye Sisay

Signature

Date of submission: July 21, 2020

Place: Bahir Dar

This thesis has been submitted for examination with my approval as a university

advisor.

Advisor’s Name: Dr.-Ing. Belachew Bantyirga

Advisor’s Signature:


MSc. Thesis By Firew Tsegaye/Power System Engineering/BIT/BDU Page ii

© July 21, 2020

FIREW TSEGAYE SISAY

POWER QUALITY PROBLEMS IN INDUSTERIAL ENTERPRISES AND THEIR

MITIGATION TECHNIQUES

CASE STUDY IN AMHARA PLASTIC PIPE FACTORY

ALL RIGHTS RESERVED


MSc. Thesis By Firew Tsegaye/Power System Engineering/BIT/BDU Page iii


MSc. Thesis By Firew Tsegaye/Power System Engineering/BIT/BDU Page iv

ACKNOWLEDGEMENTS

First and foremost, I thank the Almighty God for his mercy and grace, and strength and

persistent to finalize this thesis work. I would like to express my deepest thanks to my

advisor Dr. Ing. Belachew Bantyirga his diligent and valuable guidance, unreserved

support and encouragement throughout the thesis work. Thank you very much for clear

guidance, critical suggestions, constructive comments and interesting discussion from the

beginning to the end of the entire thesis work.

I am thankful for amhara plastic pipe factory management teams and staff for allowing

me to do my study in their reputed factory. My specials thanks to Mr. Abraraw Addis for

his kind support in providing the resources and information and help me in collecting

data for this study. Finally, I would like to express my deepest thanks to my family for

their marvelous support and encouragement throughout this thesis work. Last, but not

least thanks my friends and all my staff members for their help and encouragement.


MSc. Thesis By Firew Tsegaye/Power System Engineering/BIT/BDU Page v

ABSTRACT

Electric energy is essential for real world. Electric power system is the integration of

generation, transmission and distribution stations. It is a network of electrical components

deployed to supply, transfer, and use of electrical power. In order to use the utmost

benefit from the entire electrical power system, a proper electric power quality should be

maintained. There are several PQ problems that can significantly affect the performance

of electric equipment in the industries and affect the day-to-day activities of individual

consumers. Hence, industries should give high priority for mitigation measures in case

PQ problems occur by various factors. The present study was carried out with the main

objective to assess the PQ problems of industrial enterprises and evaluate the PQ problem

mitigation techniques taking APPF as a case. The data collected were analyzed based on

acceptable values set by IEEE 519-1992 standard that is suitable for developing

mitigation power quality problem models. Modeling was done using DVR and SAPF

models. MATLAB software was employed to analyze the data and run the models. The

Simulation of factory power distribution system with and without PQ problem mitigation

techniques were carried out using MATLAB/SIMULINK. Result analysis was also done

by comparisons of factory power distribution system with and without mitigation

techniques, which considered cost and IEEE standard. Moreover, the PQ problems were

evaluated based on IEEE standard. Results reveal that the three phases to ground fault is

occurred at distribution line and the voltage sage occurred around 65.78% rms, which

was unacceptable voltage according to the IEEE standard. But when DVR is connected,

injected missing voltage around 34% rms, the voltage variation is solved and acceptable

by IEEE standard. Results also show that the THD of the factory is 11.52% indicating it

is beyond the IEEE standard (i.e. 5%). However, when SAPF is connected, the THD

reduced from 11.52% to 0.21% implying it fits the acceptable IEEE standard. The

simulation result of this thesis depicts that DVR provides better response to protect

voltage sage problem occurs on sensitive loads. The cost and recompense period of DVR

results confirm that DVR has relatively low cost, small in size and fast dynamic response

time. Based on the results found of this thesis, it is recommended that the factory should

consider using both the DVR and SAPF effective PQ mitigation techniques.

Keywords: Active power filter, dynamic voltage restorer, mitigation technique.


MSc. Thesis By Firew Tsegaye/Power System Engineering/BIT/BDU Page vi

TABLE OF CONTENTS

Contents Page No

DECLARATION ................................................................................................................. i

ACKNOWLEDGEMENTs................................................................................................ iv

Abstract ............................................................................................................................... v

LIST OF FIGURES ............................................................................................................ x

LIST OF TABLES ........................................................................................................... xiii

LIST OF ACRONYMS ................................................................................................... xiv

LIST OF SYMBOLS ........................................................................................................... i

CHAPTER ONE ................................................................................................................. 1

1. INTRODUCTION .......................................................................................................... 1

1.1. Background .............................................................................................................. 1

1.2. Background of the study area ................................................................................... 2

1.3. Motivation ................................................................................................................ 5

1.4. Statement of the problem ......................................................................................... 5

1.5. Objective of the thesis .............................................................................................. 6

1.5.1. General Objective ............................................................................................... 6

1.5.2. Specific Objective .............................................................................................. 6

1.6. Research Methodology ............................................................................................. 6

1.7. Scope of the Study .................................................................................................... 7

1.8. Significance of the study .......................................................................................... 7

1.9. Organization of the Thesis ....................................................................................... 8

CHAPTER TWO ................................................................................................................ 9

2. LITERATURE REVIEW AND THEORETICAL BACKGROUND OF STUDY ....... 9

2.1. Power quality issues in electrical power system .................................................... 13


MSc. Thesis By Firew Tsegaye/Power System Engineering/BIT/BDU Page vii

2.1.1. Interruptions ..................................................................................................... 14

2.1.2. Waveform distortion ......................................................................................... 14

2.1.3. Frequency variations ........................................................................................ 15

2.1.4. Transients ......................................................................................................... 15

2.1.5. Short Duration Voltage Variation .................................................................... 15

2.1.6. Long Duration Voltage Variation ..................................................................... 15

2.1.7. Voltage Sage ..................................................................................................... 16

2.1.8. Voltage swell .................................................................................................... 17

2.1.9. Voltage unbalance ............................................................................................ 18

2.1.10. Voltage fluctuation ........................................................................................ 18

2.1.11. Flicker ............................................................................................................ 19

2.1.12. Harmonics ...................................................................................................... 19

2.1.13. Electrical line noise ....................................................................................... 21

2.2. Voltage disturbance IEEE standard ........................................................................ 21

2.3. Dynamic Voltage Restorer (DVR) and Active Power Filter (APF) ....................... 24

2.3.1. Theoretical background of FACTS devices ........................................................ 24

2.3.2. Dynamic Voltage Restorer (DVR) ................................................................... 25

2.3.2.1. Series injection transformer/booster transformer ......................................... 26

2.3.2.2. Harmonic filter ............................................................................................. 27

2.3.2.3. Voltage source inverter ................................................................................. 27

2.3.2.4. Storage devices ............................................................................................. 28

2.3.2.5. Control systems ............................................................................................ 28

2.3.3. Compensation strategies of DVR ........................................................................ 28

2.3.3.1. Pre-sag compensation ................................................................................... 29

2.3.3.2. In-phase compensation ................................................................................. 30


MSc. Thesis By Firew Tsegaye/Power System Engineering/BIT/BDU Page viii

2.3.3.3. Combining both pre-sag and in-phase compensation method ...................... 31

2.4. Harmonics Distortion ............................................................................................. 33

2.4.1. Total Harmonic Distortion (THD) ................................................................... 34

2.4.2. Sources of Harmonics ...................................................................................... 34

2.4.3. Effects of Harmonics ....................................................................................... 35

2.4.4. Types of Harmonic filter .................................................................................. 36

CHAPTER THREE .......................................................................................................... 40

3. POWER QUALITY PROBLEMS IN THE TEST SYSTEM SITE AND PROPOSED

MITIGATION METHOD ................................................................................................ 40

3.1. Mitigation of voltage sag using Dynamic Voltage Restorer .................................. 40

3.1.1. Equivalent circuit of DVR ................................................................................ 40

3.1.2. Mathematical modeling for voltage injection by DVR system ........................ 41

3.1.3. Control system for dynamic voltage restorer ................................................... 42

3.1.4. Injection Transformer ....................................................................................... 44

3.2. Mitigation of Harmonic Distortion using Shunt Active Power Filter .................... 45

3.2.1. Mathematical Analysis of Shunt Active Power Filter ...................................... 45

3.2.2. Voltage source inverter of shunt active power filter ........................................ 50

3.2.3. Selection of DC side capacitor ......................................................................... 51

3.2.4. Selection of DC voltage reference .................................................................... 52

3.2.5. Selection of Filter inductance ........................................................................... 53

3.2.6. Harmonic Current Extraction Methods ............................................................ 54

3.2.7. Instantaneous Real and Reactive Power Theory (p-q method) ........................ 54

3.2.8. PI controller for Shunt Active Power Filter ..................................................... 61

3.2.9. Hysteresis band current control ........................................................................ 63


MSc. Thesis By Firew Tsegaye/Power System Engineering/BIT/BDU Page ix

CHAPTER FOUR ............................................................................................................. 65

4. SIMULATION RESULTS AND DISCUSSION ......................................................... 65

4.1. Mitigation of Voltage sag problem ........................................................................ 65

4.1.1. Three phase fault occur on factory distribution system ................................... 66

4.2. Simulink model of multistage voltage sage without DVR ..................................... 66

4.2.1. Multistage faults ............................................................................................... 67

4.3. Performance solution of factory voltage sage power quality problem ................... 67

4.4. Performance solution three phase to ground fault .................................................. 69

4.5. SIMULINK model of Multistage Voltage Sage with DVR ................................... 70

4.6. Mitigation of Harmonic distortion ......................................................................... 73

4.7. Performance solution for Harmonic Distortion ...................................................... 76

4.8. Result analysis and comparison of before and after SAPF implement .................. 78

4.9. Annual cost/tariff and recompense period of DVR ................................................ 81

CHAPTER FIVE .............................................................................................................. 85

5. CONCLUSIONS AND RECOMMENDATIONS ....................................................... 85

5.1. Conclusions ............................................................................................................ 85

5.2. Recommendations .................................................................................................. 86

6.3. Future Work ........................................................................................................... 86

Reference .......................................................................................................................... 87

APPENDIX ....................................................................................................................... 92

APPENDIX A: Factory single line Load flow analysis diagram .................................. 92

APPENDIX B: Total electrical load of APPF .............................................................. 93

APPENDIX C: Electricity tariff category ................................................................... 110


MSc. Thesis By Firew Tsegaye/Power System Engineering/BIT/BDU Page x

LIST OF FIGURES

Figure 1.1 Partially parts of APPF ...................................................................................... 3

Figure 1.2 Single line diagram of amhara plastic pipe factory distribution system ........... 4

Figure 2.1 Voltage signal with long interruption .............................................................. 16

Figure 2.2 Voltage sag ...................................................................................................... 16

Figure 2.3 Voltage swell ................................................................................................... 18

Figure 2.4 Voltage fluctuations......................................................................................... 18

Figure 2.5 Flicker waveform............................................................................................. 19

Figure 2.6 DVR voltage waveforms ................................................................................. 26

Figure 2.7 Schematic diagram of DVR............................................................................. 26

Figure 2.8 Basic three-phase inverter ............................................................................... 28

Figure 2.9 Vector diagram for pre-sag compensation technique ...................................... 30

Figure 2.10 Vector diagram for in-phase compensation technique .................................. 30

Figure 2.11 Combining both pre-sag and in-phase compensation techniques .................. 31

Figure 2.12 Periodic distorted waveforms ........................................................................ 33

Figure 2.13 (a) Low pass filter (b) High pass filter .......................................................... 37

Figure 2.14 Active filter .................................................................................................... 37

Figure 2.15 Series APF circuit diagram ............................................................................ 38

Figure 2.16 Shunt active power filter circuit diagram ...................................................... 39

Figure 2.17 UPQC circuit diagram ................................................................................... 39

Figure 3.1 Equivalent circuit of DVR ............................................................................... 40


MSc. Thesis By Firew Tsegaye/Power System Engineering/BIT/BDU Page xi

Figure 3.2 DVR voltage injection schematic diagram ..................................................... 41

Figure 3.3 Flow chart of feed forward control technique for dynamic voltage restorer

based on dqo transformation ............................................................................................. 43

Figure 3.4 Converter with an open star/star transformer connection................................ 44

Figure 3.5 Basic compensation principle of a SAPF ........................................................ 45

Figure 3.6 Block diagram of SAPF................................................................................... 45

Figure 3.7 Shunt active power filter and its phasor diagram ............................................ 49

Figure 3.8 Voltage source converter for shunt active power filters .................................. 50

Figure 3.9 P-Q method control strategy ............................................................................ 56

Figure 3.10 LPF with feed-forward effect ........................................................................ 59

Figure 3.11 Principle of instantaneous active and reactive power theory ........................ 60

Figure 3.12 PI control with unit sine vector block diagram ............................................. 61

Figure 3.13 Hysteresis band current controller block ....................................................... 63

Figure 3.14 Hysteresis band current controller graph ....................................................... 64

Figure 3.15 Demonstration of hysteresis band current controller using MATLAB/

SIMULINK ....................................................................................................................... 64

Figure 4.1 Simmulink model of factory with three phases to ground fault without using

DVR .................................................................................................................................. 65

Figure 4.2 SINULINK result of rms value at three phases to ground faults .................... 66

Figure 4.3 Simmulink model of factory with multistage voltage sage faults without

dynamic voltage restorer ................................................................................................... 66

Figure 4.4 Simulink result rms voltage of multistage faults without DVR ...................... 67

Figure 4.5 Simmulink model of factory with three phase sag with DVR ......................... 68

Figure 4.6 Simulink model of DVR .................................................................................. 68


MSc. Thesis By Firew Tsegaye/Power System Engineering/BIT/BDU Page xii

Figure 4.7 SIMULINK result of rms at three phase to ground faults without DVR ........ 69

Figure 4.8 Injected rms voltage by DVR .......................................................................... 69

Figure 4.9 Simulink result of rms voltage at three phases to ground fault with DVR...... 70

Figure 4.10 SIMULINK model of factory multistage voltage sage with DVR ................ 71

Figure 4.11 Simulink result of rms at multistage faults without DVR ............................. 71

Figure 4.12 Injected rms voltage by DVR for multistage faults ....................................... 72

Figure 4.13 Simulink result of rms voltage multistage fault with DVR ........................... 72

Figure 4.14 Simulink model of amhara plastic pipe factory before filter ......................... 74

Figure 4.15 Source voltage waveform of phase ‘a’ without SAPF .................................. 74

Figure 4.16 Source current waveform of phase ‘a’ without SAPF ................................... 75

Figure 4.17 Load current waveform of phase ‘a’ without SAPF ...................................... 75

Figure 4.18 Simulink model of shunt active power filter for APPF ................................. 76

Figure 4.19 Source voltage waveform of phase ‘a’ with filter ......................................... 76

Figure 4.20 Source current waveform of phase ‘a’ with filter .......................................... 77

Figure 4.21 Load current waveform of phase ‘a’ with filter ............................................. 77

Figure 4.22 FFT analysis of source current waveform after compensation ..................... 80

Figure 4.23 Harmonics spectrum ...................................................................................... 78

Figure 4.24 FFT analysis of source current waveform before filtering ............................ 79

Figure 4.25 Comparison of current THD before and after compensation ........................ 81


MSc. Thesis By Firew Tsegaye/Power System Engineering/BIT/BDU Page xiii

LIST OF TABLES

Table 2.1 Definition of voltage disturbance ..................................................................... 22

Table 2.2 IEEE 519-1992 Current harmonics limits (69kV) .......................................... 23

Table 2.3 IEEE 519-1992 Current harmonics limits (69-169kV)..................................... 23

Table 2.4 IEEE 519-1992 Current harmonics limits (161kV) ........................................ 23

Table 2.5 IEEE 519-1992 voltage harmonics limits ......................................................... 23

Table 4.1 Simulation parameters ...................................................................................... 73

Table 4.2 Current harmonic distortion after compensation .............................................. 80

Table 4.3 Current harmonic distortion before compensation ........................................... 79

Table 4.4 Comparison THDi with and without SAPF ...................................................... 81


MSc. Thesis By Firew Tsegaye/Power System Engineering/BIT/BDU Page xiv

LIST OF ACRONYMS

AF

APPF

ASD

ATS

CBEMA

CPD

CSI

DB

DFT

DigSILENT

DVR

EM

EPQ

FACTS

HBCC

IEEE

IGBT

KVA

KVAR

KW

PI

PL

PLC

PQ

THD

UPQC

Active Filter

Amhara Plastic Pipe Factory

Adjustable Speed Drives

Automatic Transfer Switch

Computer and Business Equipment Manufacturers' Association

Custom Power Devices

Current Source Inverter

Distribution Board

Discrete Fourier Transfer

DIgital SImuLation and Electrical Network calculation

Dynamic Voltage Restorer

Energy Meter

Electrical Power Quality

Flexible Alternating Current Transmission System

Hysteresis Band Current Control

Institute of Electrical and Electronics Engineers

Insulated Gate Bio-polar Transistor

Kilo-Volt-Ampere

Kilo-Volt-Ampere-Reactive

Kilowatt

Proportional Integration

Production line

Programmable Logic Control

Power Quality

Total Harmonic Distortion

Unified Power Quality Conditioner


MSc. Thesis By Firew Tsegaye/Power System Engineering/BIT/BDU Page i

LIST OF SYMBOLS

𝐼𝑠𝑐 Short Circuit Current

𝑉𝑙𝑜𝑎𝑑 Load voltage

𝐼ℎ Harmonics Current

𝑇𝐻𝐷𝑉 Total Harmonic Distortion voltage

𝑇𝐻𝐷𝑖 Total Harmonic Distortion current

𝐼𝐿 Load Current

𝑉𝑝𝑟𝑒_𝑠𝑎𝑔 Pre-sag voltage

𝑉𝑠𝑎𝑔 Voltage sag

𝑉𝐷𝑉𝑅 DVR injected voltage

𝑉𝑝𝑐𝑐 Point of common coupling voltage

𝑉ℎ ℎ𝑡ℎHarmonic peak voltage

𝜑ℎ ℎ𝑡ℎHarmonic current phase

𝜃ℎ ℎ𝑡ℎHarmonic voltage phase

𝜔 Angular Frequency

𝑓 Fundamental frequency

𝑍𝑙𝑖𝑛𝑒 Line impendence

𝑉𝑠𝑜𝑢𝑟𝑐𝑒 System voltage during any fault condition

𝑆𝐷𝑉𝑅 Apparent power voltage to the load voltage

𝑉𝑟𝑒𝑓 Reference voltage

𝑝𝑓 Fundamental real power

𝑝𝑟 Fundamental reactive power

𝑝ℎ Harmonic power drawn by the load

𝑝𝑐 Ideal power compensation


MSc. Thesis By Firew Tsegaye/Power System Engineering/BIT/BDU Page ii

𝑖𝑠𝑎∗ Source current after compensation

𝐼𝑠𝑝 Desired source current

𝐶𝐷𝐶 DC side capacitor

𝐸𝑚𝑎𝑥 Maximum Energy

𝑉𝐷𝐶,𝑝_𝑝𝑚𝑎𝑥 Peak to peak voltage ripple

𝑉𝑝𝑝 Peak to peak voltage

𝑚𝑠 Modulation ratio of PWM converter

𝑘𝑝 Derivation gain

𝑘𝑖 Integral gain

𝑤𝑛 Natural frequency

𝐼𝑎𝑏𝑐∗ Reference current

𝐼𝑓𝑎𝑏𝑐 Actual filter current

𝐼𝑒 Error current


MSc. Thesis By Firew Tsegaye/Power System Engineering/BIT/BDU Page 1

CHAPTER ONE

1. INTRODUCTION

1.1. Background

Electric power quality, or simply power quality, can be described as the electrical limits

which permit the equipment to operate in an intended way without making any major loss

in its way of working or in the longevity [1]. Power quality is described as the variation

of voltage, current and frequency in a power system [2]. It refers to a wide variety of

electromagnetic phenomena that characterize the voltage and current at a given time and

at a given location in the power system.

Power quality involves voltage, frequency, and waveform. In general, it is useful to

consider power quality as the compatibility between what comes out of an electric outlet

and the load that is plugged into it. Good power quality can be defined as a steady supply

voltage that stays within the prescribed range. It is the overall result of the integration of

the generation, transitional and distribution stations. Hence, the power quality has to be

checked and appropriate mitigation measures should be applied for efficient use of

electric power.

There are several power quality problems. The most common power quality problems

include short duration variations (sags, swells and interruption), long duration variations

(under voltages and over voltages), voltage imbalance, waveform distortion (harmonics,

notching, and noise), voltage fluctuations and power frequency variations and transients

[3]. Power quality problems can significantly affect the performance of electric

equipment in the industries and affect the day-to-day activities of individual consumers.

Power quality issues are of vital concern in most industries today, because of the increase

in the number of loads sensitive to power disturbances. The power quality is an index to

quality of current and voltage available to industrial, commercial and customers. These

power quality problems may cause abnormal operations of facilities or even trip

protection devices. It can significantly contribute to the fail information technology

equipment like microprocessor-based control system Personal Computer (PC),

Programmable Logic Controls (PLCs), Adjustable Speed Drives (ASDs) etc. These



eventually may lead to a process stoppage, trip contactors and electromechanical relays

and then disconnection and loss of efficiency in electrical rotating machines, motors

burnout and cable insulation damage [4]. Hence, industries should give high priority for

mitigation measures in case power quality problems occur by various factors.

As power quality problems relates to the non-standard voltage, current or frequency

deviation that results in failure or mis-operation of end-user equipment, the mitigation

measures to control the quality problems should mainly address to use the power as per

the recommend standard. In order to mitigate the power quality problems, the literature

describes the use of two main tools. These are Active Power Filters (APF) and Custom

Power Devices (CPDs). APF are filters that can perform the job of harmonic elimination.

CPDs are the new generation of power electronics-based equipment aimed at enhancing

the reliability and quality of power flows in low-voltage distribution networks. CPDs

include Dynamic Voltage Restorer (DVR), Distribution Static Compensator

(DSTATCOM) and Unified Power Quality Conditioner (UPQC) [2].

1.2. Background of the study area

Amhara plastic pipe factory was established in 2003 E.C in Bahir Dar town, which is

located about 565 km north to Addis Ababa. APPF is the biggest among the factories that

produce plastic products in Ethiopia. It is mainly manufacturing and supplying products

that will be used in the projects related with water sector development and construction

sectors. It produces high quality products of UPVC, HDPE, and geomembrane. It

constantly strives to meet customer needs and expectations, enhancing its market share

all over the region and to be preferred company in domestic and export markets.



Figure 1.1 Partially parts of APPF

The factory power distribution system consists of three existing distribution transformers

of capacity two 800 kVA and one 1250 kVA. The factory has one diesel generator of

capacity 1500 kVA in the factory, which is used as emergency power supply for some

critical loads.

As shown in figure 1.2 single line diagram of APPF distribution System figure, this

factory has a power consumption of 2.85 MVA from two 800 kVA and one 1250 kVA

step down transformers for UPVC, HDPE and geo membrane sheet machines and 1.6

MVA from two 800 kVA step down transformers (for new expansion plan) for green

sheet and recycle machines. Totally 4.45 MVA power is delivered by north west district

EEU from the high voltage side 15 kV main air force distribution feeder.

Based on investigation around 95% of APPF machineries are work micro-processor-

based control systems devices, which are expensive and sensitive nonlinear loads. Thus,

eventually affect the normal operation of these devices. These power quality problems

can be addressed using various mitigation measures.

The present study was carried out on the use of the power quality problems mitigation

measures in the factories. To this purpose, this study is devoted to assessing the power

problems and evaluates the application of mitigation measures/techniques in factories,

taking amhara plastic and pipe factory as a case.



Air force feeder distribution line 15 kV

T4

T515 kV/0.4 kV 15 kV/0.4 kV

800 kVA 800 kVA

0.4 KV

954 KW 64 KW 370 KW

15 KV

T1T2 T3

1250 kVA

1000 kW

619.7 kVAR

800 kVA

640 kW

396.6 kVAR

800 kVA

640 kW

396.6 kVAR

15 kV/0.4 kV15 kV/0.4 kV 15 kV/0.4 kV

0.4 kv

0.4 kV

PL 1 PL 2 PL 3 PL 4 PL 5 PL 6 PL 7 PL 8 PL 9

357 KW 300 KW 225 KW 165 KW 160 KW 234 KW 212 KW 256 KW 569 KW

New Expansion line

ATS

Automatic

Transfer

Switch

EM

EM EM

AC stand by

Generator

1500 kVA

DB 1

DR 2

PL 12PL 11PL 10

Figure 1.2 Single line diagram of amhara plastic pipe factory distribution system



1.3. Motivation

The main objective of the Ethiopia growth and transformation plan (GTPII) is to serve as

a springboard towards realizing the national vision of becoming a low middle-income

country by 2025. Industry development is one key strategy that can contribute to achieve

the objective of the GTP. The Ethiopia industrial development strategic plan (2013-2025)

provides the overall framework in terms of the vision, goal, strategies and programs that

need to be implemented in the coming thirteen years in order to support the country’s

progress towards becoming a middle-income country by the year 2025. To achieve the

ultimate objective of the country in general and the industry sector in particular, the

electric power is the key input.

However, the supply of electric power to industries is by far below the actual demand.

One reason is from the electric power system of the country as the system is not effective

in generation of electric power, transmission and distribution of power to industries and

individual customers. This results in power shortage problem. The power shortage

created a situation that strained production process of different activities including

industrial activities.

Besides the electric power system, power quality problems can also significantly affect

the industries performance. These power quality problems may cause abnormal

operations of facilities or even trip protection devices. It was reported in earlier literature

that power quality problem affects Ethiopian industries.

1.4. Statement of the problem

In context of economical activities electrical demand of Ethiopia increasing day-to-day.

Especially government begins to strategy implementation growth and transformation

plans (GTPI), because government of Ethiopia establishes new industry parks different

regions to accelerate and sustain this transformation. APPF establish early to start

industry parks in Ethiopia but the factory faced different power quality problem during

production process. Like voltage sage and harmonic distortion. To solve these power

quality problems dynamic voltage restorers and shunt active power filter is the best

mitigation techniques. This thesis focuses on power quality problems industrial

enterprises and their mitigation techniques.



1.5. Objective of the thesis

1.5.1. General Objective

The general objective of this thesis is to improve the power quality of industrial

enterprises by using power quality problem mitigation techniques.

1.5.2. Specific Objective

The specific objectives of the thesis are:

To compare harmonic distortion and voltage sage disturbance level with IEEE 519-

1992 acceptable standard.

To model DVR to mitigate voltage sag

To develop Active filters for mitigation of harmonic distortion.

To analyze the level of power quality enhancement with and without power quality

problem mitigation techniques.

1.6. Research Methodology

The present study was consulted both primary and secondary data. The primary data were

collected from the factory; whereas secondary data were gathered from various

documents through desk/literature review.

Literature review:

Various literatures was consulted/reviewed and systematically compiled in order to

understand the power supply system, power quality problems in industrial enterprises and

their mitigation techniques. The information was accessed from scientific journals,

project documents, reports, white papers, progress reports and relevant websites.

Data collection

Required data for amhara plastic pipe factory collected from factory technicians and from

head of process control manager.

Data Analysis

The data collected were analyzed based on acceptable values set by IEEE standards, and

to make suitable for developing mitigation power quality problem models.



Modeling

Modeling was done using dynamic voltage restorer and harmonic filters models

MATLAB software was employed to analyze the data and run the models.

Simulation

The simulation of factory power distribution system with and without power quality

problem mitigation techniques can be carried out in MATLAB/SIMULINK.

Result Analysis

Result analysis was done by comparisons of factory power distribution system with and

without mitigation techniques, which considered to cost and IEEE standard.

1.7. Scope of the Study

This thesis covered the use of DVR device and applied SAPF for harmonics filters to

mitigate power quality problem in industrial enterprises. These techniques used as they

considered commonly used techniques in industries. However, there are other techniques

that may consider for power quality problem mitigation measures. Hence, the scope of

this thesis is limited to the study of power quality problems in industrial enterprises and

their mitigation techniques by using DVR device and harmonics filters.

1.8. Significance of the study

This thesis identified the power quality problems and their mitigation techniques taking

amhara plastic pipe factory as a case. The results and recommendations of this thesis

have significant implication for other industries too. The main significances of this thesis:

Industries can revise the techniques for mitigation techniques of PQ problem

Industries design strategy and actions to eliminate PQ problem of their industries

Industries can maximize the life span of the equipment, and increase the

efficiency and performance of equipment

Industries can increase their productivity and overall performance

It helps managers to make good decision to address the power quality problem

It gives inputs for further reference for researchers and practitioners



1.9. Organization of the Thesis

The thesis is organized into five chapters. The first chapter discusses the introduction

part, which consists of the background, motivation, statement of the problem,

objectives, research methodology, scope of the study, and significance of the study. The

background of study is also included in chapter. Chapter two discusses power quality

problems, the power quality categories as per IEEE standard1159-1995, and their causes

and undesirable effects. Literature review is also included in chapter. In chapter three,

the thesis describes the power quality problems in the test system site and proposed

mitigation method. It also discusses about modeling power quality problem in

industrial enterprises and their mitigation techniques. Chapter four presents simulation

results and discussion. Chapter five presents the conclusions of the study with possible

recommendations and suggests some areas for future works.



CHAPTER TWO

2. LITERATURE REVIEW AND THEORETICAL

BACKGROUND OF STUDY

Various researchers have been done in the area of power quality problem and their

mitigation techniques. Basically, they focused elimination of voltage sage/voltage swell

and harmonic distortion power quality problems by using different mitigation techniques.

There are a lot of power quality problem occurred in industrial enterprises. The common

power quality problem occurred in the industrial enterprises are voltage sags, voltage

swells and harmonics distortion. This problem could affect the performance, productivity,

profitability of industrial enterprises. Therefore, it is needed to come out with the solution

to reduce this variety of disturbances/problems.

Prior studies show that several researchers have been devoted their time to define and

explain the concept of power quality problems and their mitigations. Researchers also

tried to understand the main causes of power problems and the possible mitigation

techniques to address the power quality problems in industrial enterprises. The followings

present a brief review of the work undertaken so far.

In 2017 S. Khan, et.al [5], provided various definitions of power quality. According to

IEEE 519-1992, power quality can be described as “the concept of powering and

grounding electronic equipment in manner that is suitable to the operation of that

equipment and compatible with the premise wiring system and other connected

equipment”. Another definition is “power quality can be prescribe as the electrical limits

which permit the equipment to operate in an intended way without making any major loss

in its way of working or in the longevity.” From this definition it is understood that

power quality problem explains in the form of power transmission system and it can

affect the production process of the industries.

In July 2011 A. Bangar [6], explained why the power quality is a big issue in the

industry. He mentioned that power quality has serious economic implications for

consumers, utilities and electrical equipment manufacturers. Modernization and



automation of industry involves increasing use of computers, microprocessor and power

electronics systems such as Adjustable Speed Drives (ASDs). The impact of power

quality problems is increasingly felt by customers, industrial, commercial and even

residential. He also explained power quality problem mitigation techniques are necessary

for all industry. However, he did not properly address the possible mitigation techniques.

In 2001 A. ElMofty and K. Youssef [7] also tried to discuss the effect of power quality

on the performance of industries. They explained the increased the power quality

problem has resulted in measuring power quality variations and characteristic

disturbances for different industrial categories. The devices and equipment used in

industry include microprocessor-based controls and electric devices that are sensitive to

many types of electrical disturbances besides to actual interruptions. For mitigate power

quality problem, they noted the use of Autotransformer method.

In 2008 F.A.L. Jowder [8], described four different system topologies for DVR have

been analyzed and tested with focus on the method used to acquire the necessary energy

during voltage sags. These topologies are: (i) DVR with no storage and supply-side

connected shunt converter, (ii) DVR with no storage and load-side-connected shunt

converter, (iii) DVR with energy storage with variable dc-link-voltage, and (iv) DVR

with energy storage and with constant-dc link voltage. The first two topologies take

energy from the grid and the other two topologies take energy from the energy storage

devices during the voltage sag. He also discussed about DFT approach. For this approach,

the three-phase supply distorted voltage is measured and passed to the SIMULINK block

designated as discrete Fourier.

In 2014 P. P. Kaur and S. Gupta [9], discussed about DVR as one of the custom power

devices which can improve power quality, especially voltage sags and voltage swells. As

there are more and more concerns for the quality of supply as a result of more sensitive

loads in the system conditions, better understanding of the devices for mitigating power

quality problems is important.

In April 2014 P. R. Asabe et.al, [10], presented a solution for reducing the losses

because of produced harmonics and increasing the quality of power at the consumers’



side. They argued that there is no one mitigation technique that will suitable for every

application. They recommended the best way to avoid power quality problem is by

ensuring that all equipment to be installed in the industrial plants are compatible with

power quality in power system.

In April 2017 I.A. Adejumobi et.al [11], discussed the consequence of harmonics

problem like overheating of motor, generators, transformers, and insulation familiarity.

The focused on series and parallel resonance harmonics filter, but it needs additional cost

for parallel resonance filter connect with series to capacitor bank. The explained that

series resonance filter is used to maintain power factors within the acceptable value.

In November 2016 J. Kaiwart et.al [12] explained on the journal liner reactor

harmonics problem mitigation techniques. It is the simplest means of attenuating

harmonics. The paper is also connected in series with an individual non-linear load. The

main drawback of this paper was voltage drop and increase system losses. Authors tried

to show different harmonics problem mitigation techniques such as low pass harmonic

filters, which includes one or more series elements with a set of tuned elements. The

series elements increase the input circuit effective impedance to reduce overall harmonic

and to de-tune the shunt element relative to supply and load ends. It has gained popularity

due to ability to attenuate all harmonic frequencies and achieve low level of residual

harmonic distortion. The limitation of this technique is that it has to connect in series with

the load and it can only be used with nonlinear loads, because it can cause increased

heating effect and lower life expectancy for linear loads. The technique also experiences

low leading power factor at light loads due to occurrence of voltage boosting because of

presence of shunt capacitor and reactor.

In July 2015, M. Abid et.al [13], this paper explained the harmonics mitigation

techniques by using phase shifting techniques by MATLAB simulation. The mitigation of

harmonics by employing phases shifting transformer, the mechanism of harmonics

filtering is to connect the primary winding side of the transformer. The drawback of this

harmonic filter technique is not significant value for sensitive microprocessor based

device.



In 2012 T.K. Abdel-Galil, [14] discussed about the sources of harmonics distortion

stand from the characteristic behavior of non-linear load. These sources draw a distorted

current waveform even though the supply voltage is sinusoidal. Most equipment only

produces odd harmonics. The current distortion, for each device, changes due to the

consumption of active power, background voltage distortion and changes in the source

impendence. An overview for the most common types of single and three phase non-

linear loads for residential and industrial use is provided in this paper. However, the

paper did not explain the mitigation technique 3ht and 5th harmonics problem manly occur

on rotary machineries.

In 2017 L. Ciufu, et.al, [15] discussed about the performance of different harmonics

mitigation techniques and select hybrid filter with a 99% THD mitigation performance.

However, this mitigation technique can be used only for low voltage non-linear power

source.

In 2016 K. P. Kota, [16], explained the way of mitigation harmonic distortion by using

passive filter. Passive filter has its own drawbacks such as it is bulky, it is designed for

specific purpose, it has limited compensation, and it may cause resonance if it not

designed properly.

In 2014 S. Mukherjee, N. Saxena, and A.K. Sharma, [17], showed harmonic reduction

using shunt active filter. Active filters solve the problem of harmonics in industrial area

as well as utility power distribution. The active power filter working performance is

based on the techniques used for the generation of reference current. With the

development various technologies, it resulted in the lowering of harmonics below 5% as

specified by IEEE.

In general, the literature review above concerned on harmonic problem mitigate

techniques use passive filter, autotransformer, and hybrid filter. To sum up, their

drawbacks include they are bulky, increase power loss designed for specific purpose and

limited compensation. These techniques means passive filter, autotransformer, and hybrid

filter are causes of resonance if they are not designed properly that means not significant

value for microprocessor based device. Further, the review hybrid filter use with a 99%



THD mitigation performance but this mitigation technique can be used only for low

voltage non-linear power source. This thesis used APF for mitigation of harmonics

problem. Active filter is most important for sensitive non-linear loads. It can easily

monitor load current, filter out the fundamental frequency current and analysis the

frequency and magnitude content of the remainder parameters. Further, it reduces THD

by using additional elements PI controller, filter hysteresis current control loop and dc

link capacitor. This thesis focuses on power quality improvement of APPF by using

different power quality problem mitigation techniques.

2.1. Power quality issues in electrical power system

The electric power system has rapidly grown in size and complexity with a huge number

of interconnections to meet the increase in the electric power demand. Power quality is

one of the major issues in the power system. The Institute of Electrical and Electronic

Engineers (IEEE) Standard IEEE1100 defines power quality as “the concept of powering

and grounding sensitive electronic equipment in a manner suitable for the equipment”.

Generally, Power Quality is ultimately a consumer driven issue defined as: “Any power

problem manifested in voltage, current or frequency deviation those results in failure or

main-operation of consumers’ equipment” [18].

The fulfillments of the industrial goals were possible only because the modern industries

were able to find innovative technologies that have successfully become technological

developments. Continuous production throughout the period is ensured only when the

final objective is to optimize the production while achieving maximum profit sand

achieving minimized production costs.

Modern manufacturing and process equipments demand high quality un-interruptible

power. Because of the modern manufacturing and process equipments that operate at high

efficiency require stable and defect free power supply for the successful operation of their

machines. Machines, sensitive to power supply variations are to be designed more

precisely. For instance, some instruments like adjustable speed drives, automation

devices, power electronic components etc. fall into the above category.



All electrical devices are level to failure or malfunction when exposed to one or more PQ

problems. The electrical device might be an electric motor, a transformer, a generator, a

computer, a printer, communication equipment, or a house hold appliance. All of these

devices react adversely to PQ issues, depending on the severity of problems. PQ can be

roughly broken into categories as follows:

2.1.1. Interruptions

It is the failure in the continuity of supply for a period. Here the supply signal (voltage

or current) may be close to zero. This is defined by IEC (International Electrical

technical Committee) as “lower than 1% of the declare value” and the IEEE (IEEE

Stad.1159:1995) as decrease in the voltage supply level to less than 10% of nominal for

up to one minute duration.

2.1.2. Waveform distortion

The power system network tries to generate and transmit sinusoidal voltage and current

signals. But the sinusoidal nature is not maintained and distortions occur in the signal.

The cause of wave form distortions are:

DC Offset: The DC voltage which is presented in the signal is known as DC

offset.

Due to the presence of DC offset, the signal shifts by certain level from its actual

reference level.

Harmonics: These are voltage and current signals at frequencies which are

integral multiples of the fundamental frequency. These are caused due to the

presence of non-linear load offense the power system network.

Inter Harmonics: These are the harmonics at frequencies which are not the

integral multiples of fundamental frequency.

Notching: This is a periodic disturbance caused by the transfer of current from

one phase to another during the commutation of a power electronic device.

Noise: This is caused by the presence of unwanted signals. Noise is caused due

to interference with communication networks.



2.1.3. Frequency variations

The electric power network is designed to operate at a specified value (50Hz) of

frequency. The frequency of the frame work is identified with the rotational rate of the

generators in the system. The frequency variations are caused if there is any imbalance

in the supply and demand. Large variations in the frequency are caused due to the

failure of a generator or sudden switching of loads.

2.1.4. Transients

The transients are the momentary changes in voltage and current signals in the power

system over a short period of time. These transients are categorized in to two types-

impulsive, oscillatory. The impulsive transients are unidirectional where as the

oscillatory transients have swings with rapid change of polarity.

There are many causes due to which transients are produced in the power system. They

are arcing between the contacts of the switches, sudden switching on heavy or reactive

equipments such as motors, transformers, motor drives, poor or loose connections and

lightening strokes.

The consequence of transient power quality problem electronics devices are show wrong

results, motors run with higher temperature, and gradually reduce the efficiency and

lifetime of equipment.

2.1.5. Short Duration Voltage Variation

If the duration for which the interruption occurs is of few milliseconds, then it is called

as short interruption. Most of the time causes of these interruptions are opening of an

automatic re-closure and lightening stroke or insulation flashover. The consequences are

the data storage system may be affected and there may be malfunction of sensitive

devices like PLC’s and ASD’s

2.1.6. Long Duration Voltage Variation

If the duration for which the interruption occur is large ranging from few milliseconds

to several seconds then it is noticed long interruption. The voltage signal during this

type of interruption is shown in figure 2.1.

The causes of these interruptions are faults in power system network and improper

functioning of protective equipment. The consequence of this type of interruption leads to



the stoppage of power completely for a period until the fault is cleared.

Figure 2.1 Voltage signal with long interruption [18]

2.1.7. Voltage Sage

It is a short duration disturbance. During voltage sag, RMS voltage falls to a very low

level for short period of time. It is a reduction in RMS voltage over a range of 0.1–0.9 pu

for duration greater than 10ms but less than 1s, or can be define on the following way.

It is as the dip in the voltage level by 10% to 90% for a period of half cycle or more. The

voltage signal with voltage sag is shown in figure 2.2.

The causes of voltage sags are starting of an electric motor, which draws more current,

faults in the power system and sudden increase in the load connected to the system.

The main consequences this type of disturbance are failure of contactors and switchgear

and malfunction of Adjustable Speed Drives (ASD’s) [18].

Figure 2.2 Voltage sag



2.1.7.1. Multi phase sags and single phase sags

Based on the number of phase voltage sags are divided in to three types, they are briefly

discussed below:

1. Single phase sags

The most common voltage sags, over 70%, are single phase events which are typically

due to a phase to ground fault occurring somewhere on the system. This phase to ground

fault appears as single phase voltage sag on other feeders from the same substation.

Typical causes are lightning strikes, tree branches, and animal contacted. It is not

uncommon to see single phase voltage sag up to 30% of nominal voltage or even lower in

industrial plants.

2. Phase to phase sags

Two Phase, phase to phase sags may be caused by tree branches, adverse weather,

animals or vehicle collision with utility poles. The two phase voltage sag will typically

appear on other feeders from the same substation.

3. Three phase sags

Symmetrical three phase sags account for less than 20% of all sag events and are caused

either by switching or tripping of a three phase circuit breaker, switch or re-closer which

will create three phase voltage sag on other lines fed from the same substation. Three

phase sags will also be caused by starting large motors but this type of event typically

causes voltage sags to approximately 80% of nominal voltage and is usually confined to

an industrial plant or its immediate neighbor. As well as sudden change load current

switching of large capacitor banks and lightning the cause of occur voltage sags [19].

2.1.8. Voltage swell

Voltage swell is defined as the rise in the voltage beyond the normal value by 10% to

90% for a period of half cycle or more. The voltage signal with swell is shown in figure

2.3.

The main causes of de-energization of large load and abrupt interruption of current. The

consequences of this type of power quality problem are electronic parts get damaged

due to over voltage, insulation breakdown and Overheating.



Figure 2.3 Voltage swell [18]

2.1.9. Voltage unbalance

The unbalance in the voltage is defined as the situation where the magnitudes and phase

angles between the voltage signals of different phases are not equal.

The cause of voltage unbalance is presence of large single-phase loads and faults arising

in the system. The consequences are presence of harmonics, reduced efficiency of the

system, increased power losses and reduce the life time of the equipment.

2.1.10. Voltage fluctuation

These are a series of a random voltage changes that exist within the specified voltage

ranges. Figure 2.4 shows the voltage fluctuations that occur in a power system.

These are caused by the frequency starts/stops of electric ballasts, oscillating loads and

electric arc furnaces. Flickering of lights and unsteadiness in the visuals are the main

consequences of voltage fluctuation.

Figure 2.4 Voltage fluctuations [18]



2.1.11. Flicker

Flicker is commonly variation of system frequency. The voltage variations resulting from

flicker are often within the normal service voltage range, but the changes are sufficiently

rapid to be affecting certain end users. Flicker can be separated in to two types: cyclic and

non-cyclic. Cyclic flicker is a result of periodic voltage fluctuations on the system, while

non-cyclic is a result of occasional voltage fluctuations.

The usual method for expressing flicker is like that of percent voltage modulation. It is

usually expressed as a percent of the total change in voltage with respect to the average

voltage over a certain period of time. The figure 2.5 shows a typical flicker waveform

[20].

Figure 2.5 Flicker waveform

2.1.12. Harmonics

Harmonics are sinusoidal voltages or current shaping frequencies that are integer

multiples of the frequency at which the supply system is designed to operate (termed the

fundamental frequency; usually 50 or 60Hz). Periodically distorted wave forms can be

decomposed in to a sum of the fundamental frequency and the harmonics. Harmonic

distortion originates due to the non linear characteristics of devices and loads on the

power system. Harmonics are classified as integer harmonics, sub harmonics and inter

harmonics. Integer harmonics have frequencies which are integer multiple of

fundamental frequency, sub harmonics have frequencies which are smaller than

fundamental frequency and inter harmonics have frequencies which are greater than

fundamental frequencies. Sometimes harmonics are classified as time harmonics and

special (space) harmonics. Monitoring of harmonics with respect to fundamental is

important consideration in power system application [20].



Further Harmonics refers to both current and voltage harmonics. Harmonic voltages

occur as a result of current harmonics, which are created by non linear electronic loads.

These nonlinear loads will draw a distorted current waveform from the supply system.

Loads like electric arc furnaces, discharge lighting (such as fluorescent lamps), magnetic

cores, such as transformer and rotating machines that require third harmonic current to

excite the iron, adjustable speed drives used in fans, blowers, pumps, and process drives

can cause harmonic distortion. The effect of harmonics in the power system includes the

corruption and loss of data, overheating or damage to sensitive equipment and

overloading of capacitor banks. The high frequency harmonics may also cause

interference to nearby telecommunication system.

Using the Fourier series expansion, we can represent a distorted periodic wave shape by

its fundamental and harmonics [10].

𝑢(𝑡) = 𝑈𝑑𝑐 + ∑(𝑈(𝑛)𝑠 𝑠𝑖𝑛 (𝑛𝑤𝑡) + 𝑈(𝑛)𝑐cos (𝑛𝑤𝑡))

𝑛=1

(2.1)

The coefficients are obtained as follows:

𝑈(𝑛)𝑠 =1

𝜋∫ 𝑢(𝑡)

2𝜋

0

sin(𝑛𝑤𝑡) 𝑑𝑤𝑡 (2.2)

𝑈(𝑛)𝑐 =1

𝜋∫ 𝑢(𝑡)

2𝜋

0

cos(𝑛𝑤𝑡)𝑑𝑤𝑡 (2.3)

Where n is an integer and 𝑤 =2𝜋

𝑇.

T is the fundamental period time.

It is also common to use a single quantity, the Total Harmonic Distortion (THD), as a

measure of the effective value of harmonic distortion. Mathematically, THD values of

voltage and current, THDV and THDI, respectively, are given as follows:

𝑇𝐻𝐷𝑉 =√∑ 𝑉(𝑛)

2𝑛=2

𝑉(1)𝑥100 (2.4)

𝑇𝐻𝐷𝐼 =

√∑ 𝐼(𝑛)2

𝑛=2

𝐼(1)𝑥100 (2.5)



IEEE Standard 519-1992 defines by another term, the Total Demand Distortion (TDD).

The main difference of TDD from THD is the distortion is expressed as a percent of some

rated load current rather than as a percent of the fundamental current magnitude at the

instant of measurement [21].

𝑇𝐷𝐷 =√∑ 𝐼ℎ

2ℎ=2

𝐼𝐿𝑥100 (2.6)

Where, Ih is the harmonic currents

IL is the rated load-current

2.1.13. Electrical line noise

Electrical line noises are radio frequency interference and electromagnetic interferences

(RFI and EMI). They cause unwanted effects in computer systems. These interferences

can be caused by motor control devices, broadcast transmissions, microwave radiation,

and electrical storms. RFI and EMI can cause equipment lock-up, or data error or loss

[22].

2.2. Voltage disturbance IEEE standard

On this section try discus the relation between IEEE standards with voltage sag power

quality disturbance level. Standards associated with voltage sags are intended to be used

as reference documents describing single components and systems in a power system.

Both the manufacturers and the buyers use these standards to meet better power quality

requirements. Manufactures develop products meeting requirements of a standard, and

buyers demand from the manufactures that the product comply with the standard.

The most common standards dealing with power quality are the ones issued by IEEE,

IEC, CBEMA, and SEMI. For this thesis, IEEE standard was used.

IEEE1159-1995, “IEEE recommended practice for monitoring electric power quality”

The purpose of this standard is to describe how to interpret and monitor electromagnetic

phenomena properly. It provides unique definitions for each type of disturbance.

IEEE 1250-1995, “IEEE guide for service to equipment sensitive to momentary voltage

disturbances”



This standard describes the effect of voltage sags on computers and sensitive equipment

using solid-state power conversion. The primary purpose is to help identify potential

problems. It also aims to suggest methods for voltage sag sensitive devices to operate

safely during disturbances. It tries to categorize the voltage-related problems that can be

fixed by the utility and those which have to be addressed by the user or equipment

designer.

The second goal is to help designers o f equipment to better understand the environment

in which their device swills operate [23].

Table 2.1 Definition of voltage disturbance

IEEE standards for Harmonics distortions

On this section try discus the relation between IEEE Std 519-1992 standards with current

harmonic distortion level. Industries used harmonics standard, these standards have been

developed by IEEE industry applications society and the IEEE power engineering

society. This harmonic standard is IEEE Std 519-1992. This standard has been used

limits on the harmonic currents that a user can induce back into the utility power system

and also specifies the quality of the voltage that the utility should supply the user.

Table below shows the harmonic current limits based on the size of the load with respect

to the size of the power to which is connected. The ratio Isc/IL is the ratio of the short-



circuit current available at the point of common coupling to the maximum fundamental

load current.

Table 2.2 IEEE 519-1992 Current harmonics limits (69kV) [24]

Isc/IL h11 11h17 17h23 23h35 35h THD

20 4.0 2.0 1.5 0.6 0.3 5.0

2050 7.0 3.5 2.5 1.0 0.5 8.0

50100 10.0 4.5 4.0 1.5 0.7 12.0

1001000 12.0 5.5 5.0 2.0 1.0 15.0

1000 15.0 7.0 6.0 2.5 1.4 20.0

Table 2.3 IEEE 519-1992 Current harmonics limits (69-169kV) [25]

Isc/IL h11 11h17 17h23 23h35 35h THD

20 2.0 1.0 0.75 0.3 0.15 2.5

2050 3.5 1.75 1.25 0.5 0.25 4.0

50100 5.0 2.25 2.0 0.75 0.35 6.0

1001000 6.0 2.75 2.5 1.0 0.5 7.5

1000 7.5 3.5 3.0 1.25 0.7 10.0

Table 2.4 IEEE 519-1992 Current harmonics limits (161kV) [26]

Isc/IL h11 11h17 17h23 23h35 35h THD

50 2.0 1.0 0.75 0.3 0.15 2.5

50 3.0 1.5 1.15 0.45 0.22 3.75

Table 2.5 IEEE 519-1992 voltage harmonics limits [26]

Bus Voltage at PCC Individual Voltage

Distortion (%)

Total Voltage Distortion

THD (%)

Below 69 kV 3.0 5.0

69 kV to 161 kV 1.5 2.5

161 kV and above 1.0 1.5



2.3. Dynamic Voltage Restorer (DVR) and Active Power Filter (APF)

2.3.1. Theoretical background of FACTS devices

In recent year, high power semiconductor device has stimulated the development a new

application in power system is known as Flexible AC Transmission Systems (FACTS).

FACTS are power electronic devices used to control and improve power quality. These

FACTS devices based on connection can be divided in to four [27] [28], they are:

1) Series Controller - Some examples of the series FACTS devices are Thyristor

Switched Series Capacitor (TSSC), Thyristor-Controlled Series Capacitor (TCSC),

Thyristor-Switched Series Reactor (TSSR), Static Synchronous Series Compensator

(SSSC) and Dynamic Voltage Restorer (DVR).

2) Shunt Controller- Some examples of the shunt connected FACTS devices are Static

VAR Compensator (SVC), Static Synchronous Generator (SSG), Thyristor-

Controller Reactor (TCR), Thyristor- Switched Capacitor (TSC) and the Static

Synchronous Compensator (STATCOM).

3) Combined series/series Controller- This configuration provides autonomous series

reactive power compensation for each line but also transfers real power among the

lines via power link. The presence of power link between series controllers names

this configuration as “Unified Series-Series Controller”.

4) Combined series/shunt Controller- Some example of series/shunt connected

FACTS devices is Unified Power Flow Controller (UPFC), and Unified Power

Quality Conditioner (UPQC).

Further this FACTS devices have own advantage and drawback, for instance,

STATCOM is an advanced type of SVC (Static Var Compensator), the

application area of STATCOM is in transmission network. Transmission network

is fast regulation of voltage at a load or an intermediate bus. But this FACTS

dives only use for transmission system.

D-statcom (Distribution static compensator) is the other FACTS dives, it located

at load side in the distribution system, which can to eliminating or overcome the



problems of source side like voltage sag and interruption etc. Computing from

others the drawback of this devices high cost and complexes to operate.

Another FACTS devise is UPQC, it is the integration of series-active and shunt-

active power filters to mitigate any type of voltage and current fluctuations and

power factor correction in a power distribution network. The complexity and

costly is the drawback of this devices.

Based on the above points selected DVR because, it is smaller size, simple to

design, fast dynamic response to the disturbance, and cost effective solution for

the protection of sensitive loads from voltage sags and swells.

2.3.2. Dynamic Voltage Restorer (DVR)

The Dynamic Voltage Restorer (DVR) is a custom power device that is installed in a

distribution system between the supply and the critical load. It is used in power

distribution networks to mitigate voltage disturbances in the power system; it also

compensates for line voltage harmonics and reduces transients in voltage and fault

current. The main components of the DVR consist of Series injection transformer,

Harmonic filter, storage devices, voltage source inverter, DC charging unit and Control

system.

Below Figure shows a simplified system of the DVR. On the supply side, the DVR

injects a compensating voltage(𝑉𝐷𝑉𝑅)through the series injection transformer when there

is a voltage dip detected. This allows the critical load to receive an uninterrupted and

balanced voltage.



DVR

Voltage

Sensitive

Load

Figure 2.6 DVR voltage waveforms

Impedance Impedance

Filter

Control

System

Load

VDVR

Vs VLSupply

VSI

Figure 2.7 Schematic diagram of DVR

2.3.2.1. Series injection transformer/booster transformer [29]

The Injection/Booster transformer is one of the main components of DVR. It is

connecting the DVR to the distribution network via the HV-winding transforms and

couples the injected compensating voltages generated by the voltage source converters to

the incoming supply voltage.

In addition, the Injection/Booster transformer serves the purpose of isolating the load

from the system (VSI and control mechanism).



There are two types of connections in the three-phase system - a single three-phase

transformer connects in series to the supply, or three single-phase transformers connect to

each supply phase. This method can limit the coupling noise from the primary side to the

secondary side. The injection transformer in the DVR system connects the system to the

supply and the load, and injects the compensating voltages generated by the voltage

source inverters. It also separates the load from the power filters and the control

mechanisms.

2.3.2.2. Harmonic filter

The harmonic filter limits the harmonics generated by the VSI and can be placed in the

high or low voltage side ending of the transformer. It is usually connected on the

secondary winding side of the injection transformer because it will prevent harmonics

entering the load supply.

2.3.2.3. Voltage source inverter

The voltage source inverter is power electronics includes a storage device and switching

devices that can generate a sinusoidal voltage at any required frequency, magnitude, and

Phase Angle. The VSI supplies voltage to the load in replacement of the mains supply.

There are four main types of switching devices: Metal Oxide Semiconductor Field Effect

Transistors (MOSFET), Gate Commutated Thysistors (GTO), Insulated Gate Bio-polar

Transistor (IGBT), and Insulated Gate Commutated Thysistors (IGCT). Each type has its

own benefits and drawbacks. For this thesis used IGBT.

These voltage source inverters are widely used in low and high power applications such

as motor drives, UPS and bi-directional AC-DC converters.

In the voltage source inverter, the values of output voltage variations are relatively low

due to capacitor but it is difficult to limit current because of capacitor. The inverters are

then connected in series to the distribution line through a set of three single-phase

injection transformers. The most common voltage source inverter type is three-phase

bridge inverters, below in figure 2.8, show three-phase bridge inverters [29].



Figure 2.8 Basic three-phase inverter

2.3.2.4. Storage devices

The purpose of storage devices is to supply the necessary energy to the VSI via a dc link

for the generation of injected voltage. The different kinds of energy storage devices are

Super Conductive Magnetic Energy Storage (SCMES), batteries and capacitance.

The DC charging circuit is used after sag compensation event the energy source is

charged again through dc charging unit. It is also used to maintain dc link voltage at the

nominal dc link voltage.

2.3.2.5. Control systems

The DVR’s control system has three main functions: to detect variation in the supply

voltage; to make a compare is on between the supply voltage and a predetermined

reference voltage; and to generate switching pulses which drive the VSI, which in turn

generates the DVR output voltage, correction of any anomalies in the series voltage

injection and terminate of the trigger pulses when the event has passed.

2.3.3. Compensation strategies of DVR

The compensation control technique of DVR is the mechanism used to track supply

voltage and synchronized that with pre-sag supply voltage during a voltage sag/swell in

the upstream of distribution line. Generally, voltage sags are associated with a phase

angle jump in addition to the magnitude change. The control technique adopted depends

on the sensitivity of the load to the magnitude, phase shift or wave shape of the voltage

waveform. Further, when deciding a suitable control technique for a particular load it



should be considered the limitations of the voltage injection capability (i.e. the rating of

the inverter and the transformer) and the size of the energy storage device.

When the system is in its normal condition, the supply voltage (Vs) is identified as pre-

sag voltage and denoted by 𝑉𝑝𝑟𝑒_𝑆𝑎𝑔. In such situation, since the DVR is not injecting any

voltage to the system, the load voltage(𝑉𝑙𝑜𝑎𝑑) and supply voltage (Vs) will be the same.

During voltage sag, the magnitude and the phase angle of the supply voltage can be

changed and it is denoted by 𝑉𝑆𝑎𝑔. The DVR is inoperative in this case and the voltage

injected will be𝑉𝑑𝑣𝑟. If the voltage sag is fully compensated by the DVR, the load voltage

during the voltage sag will be 𝑉𝑝𝑟𝑒_𝑆𝑎𝑔. Several control techniques have been proposed

for compensation.

2.3.3.1. Pre-sag compensation

This technique compensates the difference between the sagged and the pre-sag voltages

by restoring the instantaneous voltages to the same phase and magnitude as the nominal

pre sag voltage, so this technique is recommended for the non-linear loads such as

thyristor-controlled loads which use the supply voltage and its phase angle as a set point

are sensitive to phase jumps. This technique needs a higher rated energy storage device

and voltage injection transformers because there is no control on injected active power.

Fig 2.9 shows the vector diagram for the pre-fault control strategy for a voltage sag event.

This method is best suited to loads sensitive to phase angle jumps as it compensates for

both the magnitude and phase angle. In this diagram,𝑉𝑝𝑟𝑒_𝑆𝑎𝑔 and 𝑉𝑆𝑎𝑔 are voltage at the

point of common coupling (PCC), respectively before and during the sag. In this case

VDVR is the voltage injected by the DVR, which can be obtained as [2].

𝐕𝐃𝐕𝐑 = √(𝐕𝐩𝐫𝐞−𝐬𝐚𝐠𝟐 + 𝐕𝐒𝐚𝐠

𝟐 − 𝟐𝐕𝐩𝐫𝐞−𝐬𝐚𝐠𝐕𝐒𝐚𝐠𝐜𝐨𝐬𝛅) (𝟐. 𝟕)

And the required angle of injection θDVR is calculated as:



𝜃𝐷𝑉𝑅 = 𝑡𝑎𝑛−1 𝑉𝑆𝑎𝑔𝑠𝑖𝑛 𝜃

𝑉𝑆𝑎𝑔𝑐𝑜𝑠𝜃−𝑉𝑝𝑟𝑒−𝑠𝑎𝑔 (2.8)

Figure 2.9 Vector diagram for pre-sag compensation technique

2.3.3.2. In-phase compensation

In this technique the compensated voltage is in-phase with the sagged voltage and only

compensating for the voltage magnitude. Therefore this technique minimizes the voltage

injected by the DVR. Hence it is recommended for the linear loads, which need not to be

compensated for the phase angle.

As shown in fig 2.10, the phase angles of the pre-sag and load voltage are different but

the most important criteria for power quality that is the constant magnitude of load

voltage is satisfied.

𝑉𝐷𝑉𝑅 = 𝑉𝑝𝑟𝑒−𝑠𝑎𝑔 − 𝑉𝑠𝑎𝑔 (2.9)

Figure 2.10 Vector diagram for in-phase compensation technique

It should be noted that the techniques mentioned in figure 2.9 and figure 2.10 need both

the real and reactive power for the compensation and the DVR is supported by an energy

storage device.



2.3.3.3. Combining both pre-sag and in-phase compensation method

It is even possible to combine different compensation techniques described earlier, to

achieve better efficiency and ease of controllability. One such technique is combining

both the pre-sag and in-phase compensation method. In the combined technique the

system initially restores the load voltage to the same phase and magnitude of the nominal

pre-sag voltage (pre-sag compensation) and then gradually changes the injected voltage

towards the sag voltage phase. Ultimately the compensated voltage is in same magnitude

and phase angle with the pre-sag voltage and slowly its phase angle transferred to the

sagged voltage.

Figure 2.11 gives an idea about the compensation control strategy, when both pre-sag and

in-phase compensation techniques are combined. It is clear from the Figure when the

DVR injected voltage is Vdvr1 (at the beginning of the compensation) the system used pre-

sag compensation, and slowly the injected voltage phasor is moved towards Vdvr4 (in-

phase compensation).

Figure 2.11 Combining both pre-sag and in-phase compensation techniques

Characteristics of harmonics

Current distortion is generated by electronic loads or non-linear loads. This non-linear

load might be single phase or three-phase. The electronic loads generate positive and

negative sequence as well as zero sequence harmonic currents. The Fourier series

represents an effective way to study and analyze the harmonic distortion [30]. Below

briefly discussed the characteristics of harmonics.



𝑓(𝑡) = 𝑎0 + ∑[𝑎ℎ cos(ℎ𝑤𝑡) + 𝑏ℎ sin(ℎ𝑤𝑡)]

∞

ℎ=1

= 𝑎0 + ∑ 𝑐ℎ sin(ℎ𝑤𝑡) + 𝜓ℎ

∞

ℎ=1

Where, 𝑓(𝑡)= Periodic function of frequency 𝑓

𝜔 = 2𝜋𝑓- Angular frequency period

𝑇 = 1𝑓⁄ = 2𝜋

𝜔⁄ - Time period

𝑐ℎ−ℎ𝑡ℎHarmonic amplitude

ℎ𝑓 - Harmonic frequency and 𝜓ℎ- Harmonic phase

The Fourier series coefficients are given by

𝑎0 =1

𝑇∫ 𝑓(𝑡)𝑑𝑡 =

1

2𝜋∫ 𝑓(𝑡)𝑑𝑥 (2.10)

2𝜋

0

𝑇

0

𝑤ℎ𝑒𝑟𝑒 𝑥 = 𝜔𝑡

𝑎ℎ =2

𝑇∫ 𝑓(𝑡) cos(ℎ𝑤𝑡) 𝑑𝑡 =

1

𝜋∫ 𝑓(𝑡) cos(ℎ𝑥)𝑑𝑥

2𝜋

0

𝑇

0

𝑏ℎ =2

𝑇∫ 𝑓(𝑡) sin(ℎ𝑤𝑡) 𝑑𝑡 =

1

𝜋∫ 𝑓(𝑡) sin(ℎ𝑥)𝑑𝑥

2𝜋

0

𝑇

0

𝑐ℎ = √𝑎ℎ2 + 𝑏ℎ

2And 𝜓ℎ = tan−1 (𝑎ℎ

𝑏ℎ)

The distortion period of current or voltage waveform expand into a Fourier series is

expressed as follows [31].

𝐼(𝑡) = ∑ 𝐼ℎ cos(ℎ𝑤𝑡 + 𝜑ℎ)

∞

ℎ=1

𝑉(𝑡) = ∑ 𝑉ℎ sin(ℎ𝑤𝑡 + 𝜃ℎ)

∞

ℎ=1

= 𝑎0 + ∑ 𝑉ℎ. sin(ℎ. 2. 𝜋. 𝑓. 𝑡. +𝜃ℎ) (2.11)

∞

ℎ=1

Where,

𝐼ℎ − ℎ𝑡ℎ Harmonic peak current, 𝜑ℎ is the ℎ𝑡ℎharmonic current phase

𝑉ℎ − ℎ𝑡ℎ Harmonic peak voltage, 𝜃ℎis the ℎ𝑡ℎ harmonic voltage phase

𝜔- Angular frequency, 𝜔 = 2𝜋𝑓, 𝑓-is the fundamental frequency

𝑎0: Dc component and 𝑉ℎ: Peak voltage level

𝑓: Fundamental frequency and 𝜃ℎ: Phase angle



2.4. Harmonics Distortion

A pure poly-phase system is expected to have pure sinusoidal alternating current and

voltages wave forms of single frequency. But, the real situation deviates from this purity.

Real voltage and current wave forms are distorted. Normally they are called non

sinusoidal wave forms. Non sinusoidal wave form is formed with the combination of

many sine waves of different frequencies. Thus actual power system signals have

fundamental component as well as harmonic components, before proceeding to concept

of fundamental and harmonic components understand harmonic distortion in non linear

load.

A nonlinear device is one in which the current is not proportional to the applied voltage.

When a wave form is identical from one cycle to the next, it can be represented as a sum

of pure sine waves in which the frequency of each sinusoid is an integer multiple of the

fundamental frequency of the distorted wave. This multiple is called a harmonic of the

fundamental.

Furthers harmonics are defined sinusoidal voltages or currents having frequencies that are

whole multiples of the frequency at which the supply system is designed to operate (50

Hz or 60 Hz). Figure below shows that any periodic distorted waveform can be expressed

as a sum of pure sinusoids. The harmonic number (h) usually specifies a harmonic

component, which is the ratio of its frequency to the fundamental frequency [21].

Figure 2.12 Periodic distorted waveforms [32]



Harmonics have frequencies that are integer multiples of the wave form fundamental

frequency. For example, given a 50Hz fundamental waveform, the 2nd, 3rd, 4th, 5th

harmonic components will be at 100Hz, 150Hz, 200Hz and 250Hz respectively thus,

harmonic distortion is the degree to which a wave form deviates from its pure sinusoidal

values as a result of the summation of all these harmonic elements [32].

2.4.1. Total Harmonic Distortion (THD)

Total Harmonic Distortion (THD) defined as the ratio of the sum of the powers of all

harmonic components to the power of the fundamental frequency [32].

𝑇𝐻𝐷𝑖 = √∑ 𝐼𝑛

2

𝐼1𝑥100% (𝑛 = 2,3,4,5… . .) (2.12)

Where

I1 is the fundamental component of the current

In is the total harmonic component of the current

2.4.2. Sources of Harmonics

There are many sources of harmonics in electrical power system; they can be

categorized as follow:

1. Magnetization nonlinearities of transformer

Transformers magnetic material characteristic is non-linear. This nonlinearity is the

main reason for harmonics during excitation.

Sources of harmonics in transformer maybe classified into four categories they are

normal excitation, symmetrical over excitation, inrush current harmonics and DC

magnetization.

2. Rotating machines

The other source of harmonics is rotating machines. Some classifications are: magnetic

Nonlinearities of the core material cause’s harmonic generation, non-uniform flux

distribution in the air gap leads to harmonic production, and cogging is a problem when

motor fails to start produces harmonics different from those in the normal condition.

3. Arcing devices

Electric Arc Furnace, discharge type lighting, arc welders have highly non-linear voltage

and current characteristics. Arc ignitions are equivalent to a short- circuit with a decrease

in voltage. Hence they are a major source of power system harmonics.



4. Power supplies with semiconductor devices

Harmonics generated by such supplies include integer, inter and sub harmonics whose

magnitudes and frequencies depend up on the type of semiconductor devices used,

operating point, nature of load variation, etc.

5. Thyristor controlled reactors

Different types of thyristor controlled reactors used in power system like series

controller, shunt controller, static VAR compensator (SVC), fixed capacitor thyristor

controlled reactor (FCTCR), thyristors witched capacitor thyristor controlled reactor

(TSCTCR) are sources of harmonics in power system.

6. Phase controllers & AC regulators

Phase Controller for the supply of balanced electric power and AC voltage regulators

when applied both online and offline for voltage regulation will result in harmonic

generation.

2.4.3. Effects of Harmonics

Harmonics are not desirable in most applications and operations of electrical power

system; therefore it has wide adverse effects on the system. The effects of harmonics

maybe classified as:

Resonance and effect on capacitor banks

Resonance occurs when the frequency at which the capacitive and inductive reactance of

the circuit impedance are equal. At the resonant frequency, a parallel resonance has high

impedance and series resonance low impedance. Harmonic resonances create problems

in operation of power factor correction capacitors.

Effects of harmonics on rotating machine, transformer and transmission

Harmonic voltages and currents increase losses in the stator windings, rotor circuit, and

stator and rotor lamination; resulting in overheating and efficiency reduction. On

transformer, harmonic voltage increases the core losses in lamination stresses the

insulation, while harmonic current increase copper losses. On transmission, harmonics

tend to increase skin and proximity effects since both are frequency dependent.

Harmonic currents reduce the power transmitting capacity by increasing copper losses

and produce harmonic voltage drops across various circuit impedances. Harmonic

voltages reduce dielectric strength of cables by causing an increase in dielectric losses.



Effects of harmonics on consumer equipment

Considering to the study of IEEE task force on the effects of harmonics on equipment the

following consumer equipments are effects by harmonic distortion, like television

receivers and fluorescent and mercury arc lighting [20].

2.4.4. Types of Harmonic filter

The harmonic mitigation techniques are mainly line conditioning techniques. These

techniques are mainly used for the improvement of performance of the system. The main

objectives are to improve the power factor, reduction of harmonics and reactive power

compensation.

The harmonic filter is connected either in series or parallel to the load. This filter

produces voltage or current to induce in to the line which filters out the harmonics.

The different filters which are available are divided into three types. They are passive

filters, active filters and hybrid filters. Each type of filter is again classified into different

types based on the configuration and operation.

1. Passive Filters

It is series or parallel combination of passive elements such as resistors, reactors and

capacitors. They provide a low resistive path for the harmonic current to flow by

resonate in gat that particular harmonic frequency. The passive filters are generally

connected in parallel to the load for current harmonic elimination. The similarity

configure and construct and low initial & maintenance cost (compared to APF) is the

advantage of passive filter. The drawbacks are property and characteristics of filter

depend on source impedance (i.e. impedance of the system and its topology) which is

subjected to variations due to external condition and it basically able to remove some

particular harmonic components through tuning whenever the magnitude of those

harmonic components is constant and power factor of the system is low.

Further this Passive filter is again divided into two types, Low Pass Filter and High Pass

Filter.

Low pass filter: is an LCR circuit (a capacitor, a resistor and inductor are connected in

series). Low pass filter also known as single-tuned notch filter [33]. These are also used

to provide reactive power factor improvement. The low pass filter is shown in the Fig.

2.13(a).



C

R

C

R

Ground

L

Ground

L

Figure 2.13 (a) Low pass filter (b) High pass filter

High pass filter: it is also the combination of passive elements but the connection is

different from LPF. It provides a low impedance path to all the harmonic currents above

a certain frequency. The high pass filter is shown in the fig.2.13 (b).

1. Active Filters

An active filter consists of serial/parallel array of arrangement of both active and passive

components. Active filter has dynamic response and thus can remove current distortion.

It is faster than passive filter. It can also be used for reactive power compensation.

Operation of Active Filters

Active Filter generate compensating current signal by continuously monitoring the load

current with the help of some process such as p-q theory, d-q transform, sliding mode

control, DSP based algorithm etc. Now the generated compensating current is used to

generate the switching pulse and switching sequence of IGBT inverter with the help of

hysteresis controller. The inverter then generates the required harmonic current for the

load through charging and discharging of DC link capacitor and injected into the system

through coupling transformer with a phase difference to compensate the reactive power

coming from the AC mains [34].

APF

None linear

Load

Figure 2.14 Active filter



Further active filters are divided into three: series active filter, shunt active filter and

hybrid active filter.

Series active filters: they are connected in series with the line through a transformer. It

acts as a voltage source injecting voltage in series with the supply voltage. It is used to

compensate the power quality problems like voltage sag and voltage swell. It is also

operate mainly as a voltage regulator and as a harmonic isolator between the nonlinear

load and the utility source. Practically shunt active power filter are more effective and

cheaper compared to series active power filters because most of the nonlinear loads

produce current harmonics. Moreover series active power filter requires adequate

protection scheme [34].

C

Is

Vf

None-linear

Load

VSI

IL

Power

Supply

Figure 2.15 Series APF circuit diagram

Shunt Active filter: is a relatively new technology for eliminating harmonics which is

based on the power electronics devices. It consists of one or more power electronic

converters which utilize power semiconductor devices controlled by integrated circuits.

The use of active power filters to eliminate the harmonics before they enter a supply

system is the optimal method of dealing with the harmonics problem. APFs could be

connected either in series or in parallel to power systems; therefore, they can operate as

either voltage sources or current sources. Mostly APF use Voltage Source Inverter (VSI).

It is connected in parallel to the load. It is used to current harmonics mitigation, reactive

power compensation and power factor correction. The compensation principle for the

SAPF is that the VSI is controlled to inject the compensation currents into the system.



The control is based on the reference currents calculated by control strategies

implemented. This is done by estimating the harmonics and the SAPF acts as a current

source injecting harmonics of same magnitude but phase shifted by 180o. The filter is

operated in such a way that the source supplies only the fundamental current and the filter

supplies the harmonic current to the system, it is also cancels the harmonic currents

produced by the non-linear load. The circuit diagram is shown in the fig.2.16.

Is

None-linear

Load

VSI

IL

IC

C

Power

Supply

Figure 2.16 Shunt active power filter circuit diagram

Unified Power Quality Conditioner: it is a combination of both shunt and series Active

Power Filter. It has the advantages of both series and shunt active filters. This filter can

be used to compensate different types of power quality problems faced in the power

system. The circuit diagram is shown in the fig.2.17.

C

Is

Vf

None-linear

Load

VSI

IL

IC

VSI

Power

Supply

Figure 2.17 UPQC circuit diagram



CHAPTER THREE

3. POWER QUALITY PROBLEMS IN THE TEST SYSTEM SITE

AND PROPOSED MITIGATION METHOD

3.1. Mitigation of voltage sag using Dynamic Voltage Restorer

3.1.1. Equivalent circuit of DVR

The compensation of voltage sag can be limited by several factors, including finite DVR

power rating, loading conditions, power quality problems and types of sag/swell. If a

DVR is a successful device, the control can handle most sags/swells and the performance

must be maximized according to the equipment inserted. Otherwise, the DVR may not be

able to avoid tripping and even cause additional disturbances to the loads.

The circuit of DVR in figure below shows a mechanism to solve this problem. on

detection of any reduction in the supply voltage Vsource from any set value, the DVR

injects a voltage, VDVR, in series through the injection transformer such that the desired

load voltage, Vload can be maintained at the load end.

Load

VDVRZdvrZline

Vsource

Figure 3.1 Equivalent circuit of DVR [35]

As pre-sag compensation technique use, DVR injection voltage is written as in equation

(3.1).

𝑉𝐷𝑉𝑅 = 𝑉source − 𝑉𝑙𝑜𝑎𝑑 + 𝑍𝑙𝑖𝑛𝑒𝐼𝑙𝑜𝑎𝑑 (3.1)

Where Vload = Desired load voltage

Zline = Line impedance

Iload = Load current

Vsource = System voltage during any fault condition

VDVR = DVR injected voltage



3.1.2. Mathematical modeling for voltage injection by DVR system

During normal condition means if the supply voltage is not sagged or swelled, then the

Vload equal to Vsource and the DVR injected voltage will be a very small quantity and (Zline

Iload) which is required to compensate for the line voltage drop. However, when voltage

sag occurs in the distribution system, the DVR control system calculates and synthesizes

the voltage required to preserve output voltage to the load by injecting a controlled

voltage with a certain magnitude, phase angle and frequency into the distribution system

to the critical load [6] [35].

RthjXth

VL

PL + jQL

Vth

DVR

VDVR

VSI

Energy

Storage

Zth

Figure 3.2 DVR voltage injection schematic diagram

Consider the schematic diagram shown in figure 4.2.

𝑍𝑡ℎ = 𝑅𝑡ℎ + 𝑋𝑡ℎ (3.2)

𝑉𝐷𝑉𝑅 + 𝑉𝑡ℎ = 𝑉𝐿 + 𝑍𝑡ℎ 𝐼L (3.3)

Where: 𝑉𝑡ℎ: The desired load voltage magnitude

𝑍𝑡ℎ: The load impedance

𝑉𝐿: The system voltage during fault condition

𝐼𝐿: The load current

When dropped voltage happened at VL, VDVR will inject a series voltage VDVR through the

injection transformer so that the desired voltage VL can be maintained. Hence

𝑉𝐷𝑉𝑅 = 𝑉𝐿 + 𝑍𝑡ℎ 𝐼L − 𝑉𝑡ℎ (3.4)

The load current𝐼𝐿 is given by,



𝐼𝐿 = (𝑃𝐿 + 𝑗𝑄𝐿

𝑉𝐿) (3.5)

The equation can be rewritten as

𝑉𝐷𝑉𝑅 < 𝛼 = 𝑉𝐿 < 00 + 𝑍𝑡ℎ𝐼𝐿 < (𝛽 − 𝜃) − 𝑉𝑡ℎ < 𝛿 (3.6)

Here,𝛼, 𝛽 and 𝛿 are the angle of VDVR, 𝑍𝑡ℎ and 𝑉𝑡ℎ, respectively and θ is the load power

factor angle and is given by

𝜃 = tan−1 (𝑄𝐿

𝑃𝐿) (3.7)

Assuming the thevinin impedance is very less (𝑍𝑡ℎ ≪ 1) the voltage injected by the DVR

can be written as

𝑉𝐷𝑉𝑅 = 𝑉𝐿 − 𝑉𝑡ℎ = (1 − 𝐾)𝑉𝐿 (3.8)

Where 𝐾 indicates the ratio of source voltage to the load voltage

𝐾 =𝑉𝑡ℎ

𝑉𝐿 (3.9)

Apparent power required by the DVR (𝑉𝐷𝑉𝑅) is then calculated in terms of the apparent

load power (𝑆𝐿) [19].

𝑆𝐷𝑉𝑅 = 𝑆𝐿(1 − 𝐾) (3.10)

𝑆𝐷𝑉𝑅 = 𝑉𝐷𝑉𝑅𝐼𝐿∗ (3.11)

3.1.3. Control system for dynamic voltage restorer

A controller is required to control or to operate DVR during the fault conditions only.

The DVR control unit used based on park’s transformer. Park’s transformation is another

name dqo transformer that stands for direct-quaderature-zero transformation. This

technique work transformed from abc coordinates to dqo coordinate. The dqo signal of

both supply voltage and reference voltage splits in to direct (d) and quaderature (q) value

of the supply signal are compared with those of the reference signal. The result d and q

are then sent to the dqo-to-abc transformation of pulse is generated. This park’s

transformation requires the Phase Locked Loop (PLL) to generate a signal with the same

frequency and the phase angle of the input signal or reference signal generation. The

block diagram of the phase locked loop is illustrated in figure 3.3. The PLL circuit is used

to generate a unit sinusoidal wave in phase with mains voltage [36] [37] [38].



Voltage supply

Va, Vb, Vc

Input Vref

Converet to

dqo

Converter to dqo

coordinate system

PLL Compare

Convert to Vabc

Coordinate System

Generate signal for

PWM

Figure 3.3 Flow chart of feed forward control technique for dynamic voltage restorer based on dqo

transformation

Based on Park’s transformation below equation defined the transformation of from three

phase system Vabc to Vdqo stationary form. In this transformation, phase A is aligned to

the d-axis that is in quaderature with the q-axis. The angle between phases A to the d-axis

is defined by theta (θ).

[

𝑉𝑑

𝑉𝑞

𝑉0

] =

[ cos(𝜃) cos (𝜃 −

2𝜋

3) 1

− sin(𝜃) −sin (𝜃 −2𝜋

3) 1

1

2

1

2

1

2]

[𝑉𝑎

𝑉𝑏

𝑉𝑐

] (3.12)



And the inverse transformation (from dqo to abc reference frame) is

[𝑉𝑎

𝑉𝑏

𝑉0

] =

[ 𝑐𝑜𝑠(𝜃) − 𝑠𝑖𝑛(𝜃)

1

2

𝑐𝑜𝑠 (𝜃 −2𝜋

3) −𝑠𝑖𝑛 (𝜃 −

2𝜋

3)

1

2

1 11

2]

[

𝑉𝑑

𝑉𝑞

𝑉0

] (3.13)

3.1.4. Injection Transformer

Injection transformer has three single phase transformers for voltage injection purpose.

The converter uses only six switches to generate the three injected voltages and it has

three switches in the current path. The converter can only generate two voltage levels and

the midpoint of the DC-link is connected to the star point of the series transformers in

order to be able to inject a zero sequence voltage into the system. The DC-link voltage

must be actively balanced to avoid unbalanced DC-link voltage [39].

Figure 3.4 Converter with an open star/star transformer connection

As shown in chapter three the injected voltages are introduced into the distribution

system through an injection transformer connected in series with the distribution line. It is

known that in order to assurance the maximum reliability and effectiveness of this

restoration scheme, one of the prerequisites is to select good injected transformer.



3.2. Mitigation of Harmonic Distortion using Shunt Active Power Filter

3.2.1. Mathematical Analysis of Shunt Active Power Filter

Figure 3.5 Basic compensation principle of a SAPF

Is

None-linear

Load

VSI

IL

IC

Power

Supply

RC.LC

Rs.Ls

VdC

Vs

SAPF

Figure 3.6 Block diagram of SAPF



Based on the above figure the source voltage given by

𝑉𝑠(𝑡) = 𝑉𝑚 sin𝑤𝑡 (3.14)

The instantaneous current can be written as

𝐼𝑠(𝑡) = 𝐼𝐿(𝑡) − 𝐼𝑐(𝑡) (3.15)

Where, 𝑉𝑠(𝑡)- is the instantaneous value of the source voltage

𝑉𝑚- is the peak value of the source voltage

𝐼𝑠(𝑡)- is the instantaneous value of source current

𝐼𝐿(𝑡)- is the instantaneous value of load current and

𝐼𝑐(𝑡)- is the instantaneous value of compensation current

Non-linear load will draw current in a non-sinusoidal shape when it is connected to utility

mains. This implies that load current consists of more than one frequency component

[40], so non-linear load current 𝐼𝐿 comprises the fundamental and harmonic components,

which is represented as

𝐼𝐿(𝑡) = ∑ 𝐼ℎ𝑠𝑖𝑛(𝑛𝑤𝑡 + ∅ℎ)

∞

ℎ=1

= 𝐼1 sin(𝑤𝑡 + ∅1) + (∑ 𝐼ℎ sin(𝑛𝑤𝑡 + ∅ℎ)

∞

ℎ=2

) (3.16)

In equation below three terms Active power, reactive power and harmonics [40],

𝐼𝐿(𝑡) = 𝐼1𝑠𝑖𝑛(𝑤𝑡) + 𝐼1𝑐𝑜𝑠(𝑤𝑡) + ∑ 𝐼ℎ sin(𝑛𝑤𝑡 + ∅ℎ)

∞

ℎ=2

(3.17)

Where,

𝐼1𝑠𝑖𝑛(𝑤𝑡): - Active power

𝐼1𝑐𝑜𝑠(𝑤𝑡): - Reactive power

∑ 𝐼ℎ sin(𝑛𝑤𝑡 + ∅ℎ)∞ℎ=2 : - Harmonics

𝐼1and ∅1- are the amplitude of the fundamental current and its angle with respect

to the fundamental voltage



𝐼ℎ and ∅ℎ – are the amplitude of the 𝑛𝑡ℎ harmonic current and its angle

The instantaneous load power is computed from the supply voltage and the load current.

The load power calculation is given as [40]

𝑝𝐿(𝑡) = 𝑣𝑠(𝑡) 𝑥 𝑖𝐿(𝑡)

= 𝑉𝑚 sin𝑤𝑡 𝑥 𝐼1 sin(𝑤𝑡 + ∅1) + 𝑉𝑚𝑠𝑖𝑛𝑤𝑡 + ∑ 𝐼ℎ sin(𝑛𝑤𝑡 + ∅ℎ)

∞

ℎ=2

= 𝑉𝑚 sin𝑤𝑡(𝐼1 sin wt cos∅1 +𝐼1 cos𝑤𝑡 𝑠𝑖𝑛∅1) + 𝑉𝑚 𝑠𝑖𝑛 𝑤𝑡 ∑ 𝐼ℎ sin(𝑛𝑤𝑡 + ∅ℎ)

∞

ℎ=2

= 𝑉𝑚𝐼1 𝑠𝑖𝑛2 𝑤𝑡 ∗ 𝑐𝑜𝑠∅1 + 𝑉𝑚𝐼1 𝑠𝑖𝑛 𝑤𝑡 ∗ 𝑐𝑜𝑠 𝑤𝑡 ∗ 𝑠𝑖𝑛 ∅1 +𝑉𝑚 𝑠𝑖𝑛 𝑤𝑡

∗ ∑ 𝐼ℎ 𝑠𝑖𝑛(𝑛𝑤𝑡 + ∅ℎ)

∞

ℎ=2

(3.18)

When,

𝑝𝑓(𝑡) = 𝑉𝑚𝐼1 sin2 𝑤𝑡 ∗ cos∅1

𝑝𝑟(𝑡) = 𝑉𝑚𝐼1 sin wt ∗ cos wt ∗ sin ∅1

𝑝ℎ(𝑡) = 𝑉𝑚 sin𝑤𝑡 ∗ ∑ 𝐼ℎ sin(𝑛𝑤𝑡 + ∅ℎ)

∞

ℎ=2

𝑝𝐿(𝑡) = 𝑝𝑓(𝑡) + 𝑃𝑟(𝑡) + 𝑃ℎ(𝑡)

= 𝑝𝑓(𝑡) + 𝑃𝑐(𝑡) (3.19)

For ideal compensation only the (fundamental) real power should be supplied by the

source while all the rest power components should be supplied by the active power filter,

𝑝𝑐(𝑡) = 𝑝𝑟(𝑡) + 𝑝ℎ(𝑡)

𝑝𝑐(𝑡) = 𝑉𝑚𝐼1 𝑠𝑖𝑛 𝑤𝑡 ∗ 𝑐𝑜𝑠 𝑤𝑡 ∗ 𝑠𝑖𝑛 ∅1 +𝑉𝑚 𝑠𝑖𝑛 𝑤𝑡 ∗ ∑ 𝐼ℎ 𝑠𝑖𝑛(𝑛𝑤𝑡 + ∅ℎ)

∞

ℎ=2

(3.20)



Where, 𝑝𝑓(𝑡)- is the (fundamental) real power

𝑝𝑟(𝑡)- is the fundamental reactive power

𝑝ℎ(𝑡)- is the harmonic power drawn by the load

𝑝𝑐(𝑡)- is ideal power compensation

From 𝑝𝑓(𝑡) + 𝑝𝑟(𝑡) + 𝑝ℎ(𝑡) equation the real power needed by the load is

𝑝𝑓(𝑡) = 𝑉𝑚𝐼1𝑠𝑖𝑛2𝑤𝑡 ∗ cos ∅1 = 𝑣𝑠(𝑡) ∗ 𝑖𝑠(𝑡) (3.21)

From the above equation the source current will, after compensation is

𝑖𝑠(𝑡) = 𝐼1 cos ∅1 sin𝑤𝑡 = 𝐼𝑠𝑚 sin𝑤𝑡 =𝑝𝑓(𝑡)

𝑣𝑠(𝑡) (3.22)

There are some switching losses in the VSI, and hence the utility must supply small

overhead for the capacitor leakage and inverter switching losses in addition to the real

power of the load. The total peak current supply by the source is therefore

𝐼𝑠𝑝 = 𝐼𝑠𝑚 + 𝐼𝑠𝐼 (3.23)

Where, 𝐼𝑠𝑚 = 𝐼1 cos ∅1 sinwt - peak value of the source current

𝐼𝑠𝐼 = Switching loss current

Now for estimation of reference source current, the peak value of the reference current

𝐼𝑠𝑝 can be estimated by controlling the dc side capacitor voltage. The ideal compensation

requires the main current to be sinusoidal and in phase with the source voltage

irrespective of the load’s current nature. The desired source current after compensation

can be given as

𝑖∗𝑠𝑎 = 𝐼𝑠𝑝 sin𝑤𝑡 (3.24)

𝑖∗𝑠𝑏 = 𝐼𝑠𝑝 sin(𝑤𝑡 − 1200) (3.25)

𝑖∗𝑠𝑐 = 𝐼𝑠𝑝 sin(𝑤𝑡 + 1200) (3.26)



Where 𝐼𝑠𝑝 = 𝐼𝑠𝑚 + 𝐼𝑠𝑖 = 𝐼1 cos ∅1 + 𝐼𝑠𝐿 is the amplitude of the desired source current,

while the phase angles can be obtained from the source voltages, Hence, the waveform

and phases of the source current are known, only the magnitude of the source currents

needs to be determined.

From the above figure we draw the vector diagram of Shunt Active Power Filter as

shown figure below [41] [30].

PWM

ConverterVdc Cdc

Lc

Ic1

Vc1

jωLcIc1

is1

Ic1IL1

Vs Vc1

Figure 3.7 Shunt active power filter and its phasor diagram

𝑉𝑠 = 𝑉𝑚 sin𝑤𝑡 (3.27)

Because of the principle of active power filter compensation we should adjust 𝐼𝑐1 because

it used for compensation reactive power of the load. From the above vector diagram we

consider 𝑖𝑠1 in phase with 𝑉𝑠 and 𝑉𝑐1.

𝑉𝐶1 = 𝑉𝑠 + 𝑗𝑤𝐿𝑐𝐼𝑐1 (3.28)

𝐼𝐶1 =𝑉𝐶1 − 𝑉𝑠

𝑤𝐿𝑐=

𝑉𝐶1

𝑤𝐿𝑐(1 −

𝑉𝑠

𝑉𝐶1) (3.29)

From the above vector diagram three phase reactive power delivered from SAPF is

calculated below [42]

𝑄𝐶1 = 𝑄𝐼1 = 3𝑉𝑠𝐼𝐶1 = 3𝑉 𝑉𝐶1

𝑤𝐿𝑐(1 −

𝑉𝑠

𝑉𝐶1) (3.30)

From the above equation 𝑄𝐶1 𝑖𝑠 𝑝𝑜𝑠𝑖𝑡𝑖𝑣𝑒 𝑤ℎ𝑒𝑛 𝑖𝑓 𝑉𝐶1 > 𝑉𝑠

𝑄𝐶1 𝑖𝑠 𝑛𝑒𝑔𝑎𝑡𝑖𝑣𝑒 𝑤ℎ𝑒𝑛 𝑖𝑓 𝑉𝐶1 < 𝑉𝑠



3.2.2. Voltage source inverter of shunt active power filter

Shunt APF topologies use voltage source inverters, which have a dc voltage source at the

dc voltage. Generally a capacitor used as an energy storage device which acts a voltage

source. In this topology, inverter dc voltage from the capacitor is converted into an AC

voltage by appropriately gating the power semiconductor switches.

As shown in chapter three VSIs are preferred over CSIs because of their higher efficiency

and lower initial cost and in addition VSIs is connected in parallel.

It can generate a sinusoidal voltage with any required magnitude, frequency and phase

angle. The VSI use to either completely replace the voltage or to inject the ‘missing

voltage’. The ‘missing voltage’ is the difference between the normal voltage and the

actual. It also converts the DC voltage across storage devices into a set of three phase AC

output voltages. It is also capable to generate or absorbs reactive power. If the output of

the VSI is greater than AC bus terminal voltages, is said to be in capacitive mode. So, it

will compensate than AC reactive power through Ac system and regulates missing

voltages. These voltages are in phase and coupled with the AC system through the

reactance of coupling transformers. In addition, the converter is normally based on

energy storage, which will supply the converter with a DC voltage. The type of power

switch used is an IGBT in anti-parallel with a diode. Some of the methods of VSI control

are; Hysteresis current control method, Sinusoidal Pulse Width Modulation (SPWM)

control and Space Vector PWM control [43] [33] [44] [45].

Figure 3.8 Voltage source converter for shunt active power filters



3.2.3. Selection of DC side capacitor

The DC side capacitor (CDC ) of VSI performs two key objectives in active filtering

applications. It keeps VdC with a small ripple during steady state and behaves as an

energy storage element to supply the real power difference between source and load

during transient conditions. During steady state conditions the real power demand of the

load and a small power to compensate for the losses in the SAPF should be equal to the

real power supplied by the source. Thus VDC can be maintained at a reference value,

However, when load change occurs, the real power balance between the source and load

will be interrupted and keeps the VDC away from its reference voltage. This real power

difference is to be compensated by the CDC. In order to ensure the satisfactory operation

of the SAPF should be adjusted to change proportionally the real power drawn from the

source. If the VdC attains its reference value, the real power consumed by the load is

supposed to be equal to the real power supplied by the source. Thus, can be found by

regulating the average voltage value of theCDC. If the DC bus voltage is lower than the

reference DC bus voltage implies that the real power supplied by the source is not enough

to supply the load demand. Hence, the source current needs to be increased. In other

words, if the DC bus voltage is larger than the reference DC bus voltage, the source

current needs to be decreased. The reactive power injection may leads to the ripple

voltage of the CDC [40]. In short the selection of DC Side CapacitorCDC, are two main

purposes of DC side capacitor server: first in steady state it maintains DC voltage and the

other during transient period it serves as an energy storage element to supply power

differences. Therefore choosing of DC capacitor is very important, the DC capacitor must

be maintained with the help of a reference value.

When load condition changes, the real power balance between main and the load will be

also disturbed, which is to be compensated by DC capacitor.

During transients, DC side capacitor helps to maintain variations and ripples inVDC .

Change in CDC does not much affect the error in VDCbut by change inCDC, the settling

time and final value of VDC are affected. So, on the basic of settling time, response time

and variation in VDCthe final value of CDCis selected.



There are numerous different methods which can use for designingCDC. They are:-

CDC =2Emax

VDC2 − VDC,min

2 (3.31)

Emax is the maximum supplied energy by the capacitor in the worst case.

CDC =π ∗ Ic1,rated

√3w ∗ VDC,P−Pmax

(3.32)

WhereVDC,P−Pmax: the peak to peak voltage ripple

CDC =s

2wVDC∗∆VDC (3.33)

CDC =Vs√I5

2 + I72 − 2I5I7 cos(5α − 7α)

2wVDC2 ε

(3.34)

CDC =IH

2whVDC (3.35)

WhereIH : current of the lowest order harmonic

In this thesis select capacitor value based on the second method that observed above, the

selection of this capacitor or CDC can be governed by reducing the voltage ripple. The

specification of peak to peak voltage ripple and the rated filter current define the

capacitor [46] [47].

CDC =π ∗ Ic1,rated

√3w ∗ Vdc,P−P(max)

(3.36)

i.e. to know CDCit is necessary to know Vpp

Vpp = π ∗ Ipp ∗ c =π ∗ Ipp

w ∗ Cdc (3.37)

From equation above the max peak to peak voltage ripple can be obtained as [48].

Vpp =π ∗ Ic1,rated

√3 w ∗ Cdc

(3.38)

3.2.4. Selection of DC voltage reference

To actively control filter current Ic, the dc bus nominal voltage Vdc must be greater than

or equal to line peak voltage i.e. the filter can only compensate when Vdc > Vs, if we

assume that the PWM converter is operating in linear modulation mode (0 ≤ ma ≥ 1)

then [46],



ma =Vm

Vdc

2

=2√2 Vf1

Vdc for ma = 1, (3.39)

Where Vm = √2 Vf1

Hence, Vdc = 2√2 Vf1for ma = 1 (3.40)

Where,

Vf1 −Fundamental components in the ac-side of PWM-inverter

In the above equation Vf1is the fundamental component at AC side of PWM converter. If

the non-linear load is already known then reference dc bus voltage chose is the function

of load power and the maximum harmonic order which is the be compensated

Vdc = 2√2 V(fh)max (3.41)

Where, V(fh)max is the voltage value including harmonics of order to be compensated,

approximately becomes equal to Vs source voltage.

3.2.5. Selection of Filter inductance

The value of filter inductance should be kept small enough so that the injected current di

dt

is greater than the reference compensating current to track its reference. The value of

filter inductance can be mainly found out by reactive power requirement of the system

and harmonic cancellations. There are a number of different approaches [46]:

QLf1 = 3VsIf1 = 3Vs

Vf1

wL1(1 −

Vs

Vf1) (3.42)

If1 =Vf1wmf

wmf Lf⁄

Where mf: the modulation ratio of PWM converter

Lf =Vs

2√6fs∆If, p − p,max (3.43)

Where∆If, p − p,max: 15% of the filter current



Lf,min =VDC

8fs∆If, p − p,max (3.44)

Lf,max =VDC − 2√2Vs

2∑ wh∞h=0 Ih√2

(3.45)

Where h is the harmonic order.

Lf =VDC

6fs∆If, p − p,max (3.46)

Where∆If, p − p,max: is the maximum ripple current

In this thesis selected the filter inductance based on the first method. The performance of

the system can be observed taking difference at which the current harmonics are

minimum.

3.2.6. Harmonic Current Extraction Methods

The harmonic or reference current extraction method is classified into time-domain and

frequency- domain. The time-domain is used to extract the reference current from the

harmonic line current with simple algebraic computation. The frequency domain method

includes, Discrete Fourier Transform (DFT), Fast Fourier Transform (FFT), and

Recursive Discrete Fourier Transform (RDFT) based methods. The frequency domain

methods required large memory, computation power and the results provided during the

transient condition may be imprecise. Mostly frequency-domain work based on Fast

Fourier Transformation (FFT) method provides accurate individual and multiple

harmonic load current detection. The merit of time-domain method has fast response

compared to frequency domain, so in this thesis used time-domain method [30] [49].

3.2.7. Instantaneous Real and Reactive Power Theory (p-q method)

The performance of APF depends on the reference currents estimation process. This

process is called reference current generation. The following methods are used to

generate reference currents for the Shunt Active Power Filter.

1. Instantaneous active and reactive power theory also known as p-q theory.

2. Synchronous reference Method also known as d-q theory.



3. Root Mean Square (RMS) based algorithm.

4. Active and Reactive current methods.

For this thesis used Instantaneous active and reactive power theory (p-q theory). This

theory three phase load voltages and currents of three phase reference frame are

transformed into two phase quantities of orthogonal reference frame. The instantaneous

active and reactive powers are calculated from the orthogonal components. The

compensating currents are calculated from the instantaneous powers. By this method

reactive power compensation can also be done. There active current component can be

used for reactive power compensation.

In advance this theory, basically three phase system as a single unit and performs

Clarke’s transformation (a-b-c coordinates to the α-β-0 coordinates) over load current and

voltage to obtain a compensating current in the system by evaluating instantaneous active

and reactive power of the network system.

The p-q method control strategy in block diagram form is shown in figure below.



Load Current and Voltage Measurement

Clarke Transformation

P and q Calculation

Inverse Clarke Transformation

Compensating Current Calculation

Filter for qc

Calculation

Filter for Pc

Calculation

Figure 3.9 P-Q method control strategy

This theory works on dynamic most important as its instantaneously calculated power

from the instantaneous voltage and current in three phase circuits [33] [44] [45].

Although the method analysis the power instantaneously yet the harmonic suppression

greatly depends on the gating sequence of three phase MOSFET inverter which is

controlled by different current controller such as hysteresis controller, PWM controller,

triangular carrier current controller. But among this hysteresis current controlled method

is widely used due to its robustness, better accuracy and performance which gives to

ability to power system [44].



3.2.7.1. P-Q method mathematical modeling

The relation between load current & voltage of three phase power system and the

orthogonal coordinates (α-ß-0) system are expressed by Clarke’s transformation. The

Clarke transformation maps the three phase instantaneous voltage in the abc phase,

Va, Vb and Vc , into the instantaneous voltages on the αß0-axisVα, VβandV0. The Clarke

transformation and its inverse transformation of the phase generic voltage are given by:-

[

𝑉𝛼

𝑉𝛽

𝑉0

] = √2

3

[ 1 −

1

2−

1

2

0√3

2−

√3

21

√2

1

√2

1

√2 ]

[𝑉𝑎

𝑉𝑏

𝑉𝑐

] (3.47)

And its inverse transformation is

[𝑉𝑎

𝑉𝑏

𝑉𝑐

] = √2

3

[ 1

√2−

1

2

√3

2

1

√2−

1

2−

√3

21

√21 0

]

[

𝑉𝛼

𝑉𝛽

𝑉0

] (3.48)

Similarly, three phase generic instantaneous line currents𝐼𝑎, 𝐼𝑏and𝐼𝑐, can be transformed

on the αß0-axis by

[

𝐼𝛼𝐼𝛽𝐼0

] = √2

3

[ 1 −

1

2−

1

2

0√3

2−

√3

21

√2

1

√2

1

√2 ]

[𝐼𝑎𝐼𝑏𝐼𝑐

] (3.49)

And its inverse transformation is


] = √2

3

[ 1

√2−

1

2

√3

2

1

√2−

1

2−

√3

21

√21 0

]

[

𝐼𝛼𝐼𝛽𝐼0

] (3.50)

Where 𝑣𝑎 , 𝑣𝑏 , 𝑣𝑐 𝑎𝑛𝑑 𝐼𝑎, 𝐼𝑏 , 𝐼𝑐 represent the phase voltages and currents respectively.



𝑉0 And 𝐼0can be eliminated from transformation materials, the Clarke transformation and

its inverse transformation become

[𝑉𝛼

𝑉𝛽] = √

2

3[ 1 −

1

2−

1

2

0√3

2−

√3

2 ]

[𝑉𝑎

𝑉𝑏

𝑉𝑐

] (3.51)

And

[𝑉𝑎

𝑉𝑏

𝑉𝑐

] = √2

3

[

1 0

−1

2

√3

2

−1

2−

√3

2 ]

[𝑉𝛼

𝑉𝛽] (3.52)

Similar equation for line current

[𝐼𝛼𝐼𝛽

] = √2

3[ 1 −

1

2−

1

2

0√3

2−

√3

2 ]


] (3.53)

And

[

𝐼𝑎𝐼𝑏𝐼𝑐

] = √2

3

[

1 0

−1

2

√3

2

−1

2−

√3

2 ]

[𝐼𝛼𝐼𝛽

] (3.54)

The three phase instantaneous active power, 𝑝(𝑡)is calculated from the instantaneous

voltage and current as

𝑝(𝑡) = 𝑉𝑎(𝑡)𝑖𝑎(𝑡) + 𝑉𝑏(𝑡)𝑖𝑏(𝑡) + 𝑉𝑐(𝑡)𝑖𝑐(𝑡) (3.55)

𝑝 = 𝑉𝑎𝑖𝑎 + 𝑉𝑏𝑖𝑏 + 𝑉𝑐𝑖𝑐 (3.56)

𝑝 = (𝑉𝑎 − 𝑉𝑏)𝑖𝑎 + (𝑉𝑏 − 𝑉𝑐)𝑖𝑏 + (𝑉𝑐 − 𝑉𝑎)𝑖𝑐 (3.57)

The three phase instantaneous active power can be calculated in terms of the αß0

components if equation 3.48 and 3.50 are used to replace the 𝑎𝑏𝑐 Variables in equation

3.57.

𝑝(𝑡) = 𝑉𝑎𝑖𝑎 + 𝑉𝑏𝑖𝑏 + 𝑉𝑐𝑖𝑐 ↔ 𝑝(𝑡) = 𝑉𝛼𝑖𝛼 + 𝑉𝛽𝑖𝛽 + 𝑉𝑜𝑖𝑜 (3.58)

This expression can be given in the stationary from by

𝑝(𝑡) = 𝑉𝛼𝑖𝛼 + 𝑉𝛽𝑖𝛽 (3.59)

𝑝0(𝑡) = 𝑉𝑜𝑖𝑜 (3.60)



Similarly the instantaneous reactive power is given by

𝑞(𝑡) = −1

√3[(𝑉𝑎 − 𝑉𝑏)𝑖𝑐 + (𝑉𝑏 − 𝑉𝑐)𝑖𝑎 + (𝑉𝑐 − 𝑉𝑎)𝑖𝑏] (3.61)

Which is equivalent and the reactive power can be calculated as,

𝑞(𝑡) = 𝑉𝛼𝑖𝛼 − 𝑉𝛽𝑖𝛽 (3.62)

The instantaneous reactive power 𝑞(𝑡)takes into consideration all the current and voltage

harmonics.

From equation 3.58 and 3.61, the expression for 𝑝(𝑡)and𝑞(𝑡), can be write in matrix

form as

[𝑝𝑞] = [

𝑉𝛼 𝑉𝛽

−𝑉𝛽 𝑉𝛼] [

𝐼𝛼𝐼𝛽

] (3.63)

In general, each one of the active and reactive instantaneous power contains a direct

component and an alternating component. The direct component represents the

fundamentals of current and voltage. The alternating term represent the harmonics of

current and voltages [43].

In order to separate the harmonics from the fundamentals of the load currents, it is

enough to separate the direct term of the instantaneous power from the alternating one. A

Low Pass Filter (LPF) with feed-forward effect can be used to accomplish this task as

shown in figure [33] [44] [45].

A

Low Pass Filter

AA

+

-

-

Figure 3.10 LPF with feed-forward effect

The instantaneous reactive power produces an opposing vector with 180ο phase shift in

order to cancel the harmonic component in the line current.

From equation 3.62 and 3.63, give up equation 3.64.

[𝐼𝛼𝐼𝛽

] =1

𝑉𝛼2 + 𝑉𝛽

2 [𝑉𝛼 𝑉𝛽

−𝑉𝛽 𝑉𝛼] [

𝑃𝑞] (3.64)



By deriving from these equations, the compensating reactive power can be identified. The

compensating current of each phase can be derived by using the inverse transformations

as shown in equation 3.64

[

𝑖𝑐𝑎∗

𝑖𝑐𝑏∗

𝑖𝑐𝑐∗

] = √2

3

[ 1 0

−1

2

√3

2

−1

2−

√3

2 ]

[𝑖𝑐𝛼𝑖𝑐𝛽

] (3.65)

This instantaneous reactive theory performs instantaneously as the reactive power is

detected based on the instantaneous voltages and currents of the three phase circuits. This

will provide better harmonics compensations as the harmonics detection phase is in small

delay.

The current control strategy plays an important role in fast response current controlled

inverts such as the active power filter. Hysteresis current control method is the most

commonly proposed control method in time domain. This method provides instantaneous

good accuracy, current correction response and unconditioned stability to the system. So

beside that, this method is the most suitable for current controlled inverters [45].

The Figure below shows the block diagram of p-q method for harmonic current

extraction [42].

Inverse Clarke’s

Transformation

vs

Is

If

Iαβ

p

qLPF

LPF

-

αβ

abc

+

-

+

β

α

Filter

Reference Current

Calculation Second Order

Low Pass

Filter

Instantaneous

Power p and q

Calculation

Clarke’s

Transformation

abc

abc

αβ

αβ

Figure 3.11 Principle of instantaneous active and reactive power theory



3.2.8. PI controller for Shunt Active Power Filter

The PI controller is used to estimate the peak value of the reference current and to

regulate the dc-link capacitor voltage, or in the other word it is the controller is used to

eliminates the steady state error in the DC- side voltage [43]. The output of the PI-

controller is considered as the peak value of the estimated source or reference current.

The figure below shows the block diagram of Proportional Integrator Controller with

Unit sine vector [46] [50].

+

-

Vdc,ref

Vdc

X

Unit sine

Vector

Vc

Vb

Va

Proportional

gain

LPF

Derivative

gain

+

+

X

XI*CC

I*aC

I*bC

PI - Controller

e

Usa

Usc

Usb

Figure 3.12 PI control with unit sine vector block diagram

In this method, the DC side capacitor voltage is sensed and compared with a reference

voltage. This 𝑒𝑟𝑟𝑜𝑟 = 𝑉𝑑𝐶(𝑟𝑒𝑓) − 𝑉𝑑𝑐 is used as an input for PI controller. The error

signal is passed through Butterworth design based LPF. The LPF filter has cut-off

frequency at 50Hz that can suppress the higher order components and allow only

fundamental components. The transfer function of the PI Controller is represented as

𝐻(𝑆) = 𝐾𝑝 +𝐾𝑖

𝑆 (3.66)

Where,

𝐾𝑝- is the proportional constant that determines of dynamic response of the DC side

voltage control and

𝐾𝑖 - is the integral constant that determines it’s settling time.



The gain value is derived using the mathematical formula 𝐾𝑝 = 2ξ𝑤𝑛𝐶𝐷𝐶 and similarly

integral gain is derived using𝐾𝑖 = 𝐶𝐷𝐶𝑤𝑛2 . Where ξ =

√2

2damping factor, 𝐶𝐷𝐶 dc-link

capacitor value, wn-natural frequency, chosen as the supply fundamental frequency.

The other point is Unit sine vector, the source voltage are converted to the unit current(s)

while corresponding phase are maintained.

𝑉𝑎 = 𝑉𝑚 𝑠𝑖𝑛(𝜔𝑡)

𝑉𝑏 = 𝑉𝑚 𝑠𝑖𝑛(𝜔𝑡 − 1200)

𝑉𝑐 = 𝑉𝑚 𝑠𝑖𝑛(𝜔𝑡 + 1200)

Where,

𝑉𝑚- Peak value of the source voltage,

𝜔 = 2𝜋𝑓- Fundamental angular frequency

For harmonic free unity power factor, three-phase supply currents are estimated using the

unit sine vector templates, which are in phase with the supply voltages and its peak value.

The unit sine vector templates are derived as [46].

𝑈𝑠𝑎=

𝑉𝑠𝑎𝑉𝑠𝑚

⁄ =sin𝜔𝑡

𝑈𝑠𝑏=

𝑉𝑠𝑏𝑉𝑠𝑚

⁄ =sin(𝜔𝑡−1200) 𝑎𝑛𝑑

𝑈𝑠𝑐=

𝑉𝑠𝑐𝑉𝑠𝑚

⁄ =sin(𝜔𝑡+1200)

The amplitude of the unit sine vector template is unity in steady-state. In the transient

condition, it will try varying according to the load variation. The unit sine vector

templates are multiplied with the peak-amplitude of the estimated reference current

which is used to generate the required reference currents.

The unit current is defined as ia = sinwt , ib = sin(wt − 1200) and ic = sin(wt +

1200). The amplitude of the sine current is unit or 1 volt and frequency is in phase with

the source voltages [51].

The proportional integral controller eliminates the steady state error in the DC side

voltage. The output of the PI controller is considered as the peak value of supply current

(𝐼𝑚𝑎𝑥), which is composed as the fundamental active power component of APF. Peak



value of the current (𝐼𝑚𝑎𝑥) so obtained, is multiplied by the unit sine vectors in phase

with the respective source voltages to obtain the reference current (𝐼𝑐𝑎∗ ,𝐼𝑐𝑏

∗ ,𝐼𝑐𝑐∗ ) and sensed

with actual current (𝐼𝑎, 𝐼𝑏 , 𝐼𝑐) and are compared at hysteresis band, which gives the gating

signals for the active power filter [42].

3.2.9. Hysteresis band current control

The Hysteresis Band Current Control (HBCC) technique is used for pulse generation in

current controlled VSIs. The control method offers good stability, gives a very fast

response, provides good accuracy, low cost and has got a simple operation. The HBCC

technique employed in an active power filter for the control of line current is shown in

Figure 4.13. It consists of a hysteresis band surrounding the generated error current. The

current error is obtained by subtracting the actual filter current from there reference

current. There reference current used here is obtained by the p-q method which is

represented as𝐼𝑎𝑏𝑐∗. The actual filter current is represented as𝐼𝑓𝑎𝑏𝑐. The error signal is

then fed to the relay with the desired hysteresis band to obtain the switching pulses for

the inverter.

Iref=Iabc*

Ifabc

SWITCHING

PULSES

+-

Error

Figure 3.13 Hysteresis band current controller block

Hence, Upper limit hysteresis band = 𝐼𝑟𝑒𝑓 + max(𝐼𝑒) 𝑎𝑛𝑑

Lower limit hysteresis band = 𝐼𝑟𝑒𝑓 − min(𝐼𝑒)

Where, 𝐼𝑟𝑒𝑓= Reference Current

𝐼𝑒= Error Current

The operation of APF depends on the sequence of pulse generated by the controller.

Below figure shown the ramping of the current between the two limits where the upper

hysteresis limit is the sum of the reference current and the maximum error or the



difference between the upper limit and the reference current and for the lower hysteresis

limit, it is the subtraction of the reference current and the minimum error.

Supposing the value for the minimum and maximum error should be the same. As a

result, the hysteresis band width is equal to two times of error [33].

Figure 3.14 Hysteresis band current controller graph

Figure 3.15 Demonstration of hysteresis band current controller using MATLAB/ SIMULINK



CHAPTER FOUR

4. SIMULATION RESULTS AND DISCUSSION

4.1. Mitigation of Voltage sag problem

Before proceed to observe performance solution of voltage sag. Discuss modeling of

factory power distribution system. For factory 15 kV source proposed from Air force

feeder. As shown in figure below source voltage is 15 kV then by use proposed step

down transformer reduced from 15 kV to 380V. As discussed on chapter one APPF has a

power consumption of 2.85 MVA from two 800 kVA and one 1250 kVA step down

transformers. Each transformer is connected different loads.

Frequently occur fault single line to ground fault as discussed in chapter two, but during

gathering information from factory mostly occur on factory distribution system three

phase to ground fault. This is the reason why this type of fault is considered first. Three

phases to ground fault, each individual phases is decreased to 65.78% from their nominal

values during the period 0.05-0.15s for duration of 0.1s.

The factory power distribution system test in three phases to ground fault modeling and

the rms value before DVR connect simulation result are shown in figure 4.1 and figure

4.2 respectively.

Figure 4.1 SIMULINK model of factory with three phases to ground fault without using DVR



4.1.1. Three phase fault occur on factory distribution system

Figure 4.2 SIMULINK result of rms value at three phases to ground faults

4.2. Simulink model of multistage voltage sage without DVR

On this section multistage voltage sag represent three phase voltage sag faults occur

different time for interval of time. It is not represent fault point or location. The first fault

stage duration 0.03 – 0.08s fault was applied to all three phases. While in second stage

which has duration of 0.13-0.16s also applied to all the three phases. All phases reduced

65.78% (around 250V) from their nominal rms values (380V). The factory power

distribution system test in multistage faults modeling and the rms value before DVR

connect simulation result are shown in figure 4.3 and figure 4.4 respectively.

Figure 4.3 SIMULINK model of factory with multistage voltage sage faults without dynamic voltage

restorer



4.2.1. Multistage faults

Figure 4.4 SIMULINK result rms voltage of multistage faults without DVR

4.3. Performance solution of factory voltage sage power quality

problem

As shown on appendix a load flow analysis, it is the most important and essential

approach to investigating problems in power system operating and planning. Selection

the optimal location of DVR is effect on the power quality problem mitigation techniques

on the distribution system. So, from data load flow analysis, it indicates active power and

reactive power loss. Therefore selected DVR location is paramount for achieved power

quality improvement. Factory power distribution system including DVR and only DVR

subsystem shows in figure 4.5 and figure 4.6 respectively.



Figure 4.5 SIMULINK model of factory with three phase sag with DVR

Figure 4.6 SIMULINK model of DVR



4.4. Performance solution three phase to ground fault

The voltage sage problem of the factory power distribution system is modeled using

MATLAB/SIMULINK software. As shown in figure 4.7 simulation of voltage sage

problem without DVR voltage reduce around 65.78% (around 250V), when cause of

three phase short circuit fault occur at a system for 0.1s and the voltage is decreased to

less than 90%, so the voltage sage is needed to be compensated to get the desired voltage

level at the load side.

In figure 4.8 show the DVR application when the missing voltage occurs during voltage

sage is compensated by injected appropriate level of voltage. The compensated voltage

by injected DVR is around 34% (130V).

In figure 4.9 clearly seen the voltage waveform that after DVR connected compensation

missing voltage, this show DVR worked effectively.

Figure 4.7 SIMULINK result of rms at three phase to ground faults without DVR

Figure 4.8 Injected rms voltage by DVR



Figure 4.9 SIMULINK result of rms voltage at three phases to ground fault with DVR

4.5. SIMULINK model of Multistage Voltage Sage with DVR

In figure 4.10 shown modeling of factory power distribution with multistage faults that

consist of two three-phase ground faults, and different fault duration. As shown in figure

4.11, the simulation of voltage sage problem without DVR connected, when multistage

faults occur. Voltages reduce around 65.78% (around 250V), first stage and second stage

duration 0.03 – 0.08s and 0.13-0.16s respectively.

When the missing voltage occurs during voltage sage two different stages is DVR

compensated by injected appropriate level of voltage and the compensated voltage

waveform are shown in figure 4.12 and figure 4.13 respectively.



Figure 4.10 SIMULINK model of factory multistage voltage sage with DVR

Figure 4.11 SIMULINK result of rms at multistage faults without DVR



Figure 4.12 Injected rms voltage by DVR for multistage faults

Figure 4.13 SIMULINK result of rms voltage multistage fault with DVR



4.6. Mitigation of Harmonic distortion

This section presents the MATLAB base simulation results of with and without shunt

active power filter. The complete active power filter system is composed mainly of three

phase source, a nonlinear load, a voltage source PWM converter, PI controller, and

hysteresis band current control. All these components are modeled separately and then

integrated solved to simulate the system. Figure 4.14– figure 4.21 shows the simulations

results of the proposed shunt active power filter controlled by PI controller with

MATLAB software. The parameters selected for simulation studies are given in table 4.1.

Table 4.1 Simulation parameters

Parameters Value

DC reference voltage 700 V

Line inductance 2.5 µH

Filter inductance 3 mH

DC link capacitance 2600 µF

Load inductance 30 mH

Load resistance 10 Ω

Load capacitance 1 µF

System frequency 50 Hz

Three phase source voltage 400 V

Proportional constant, Kp 0.0183

Integral constant, Ki 6.5



In figure 4.14 factory power distribution system modeled by MATLAB /SIMULINK

software. Before connect SAPF source voltage and load current waveform are shown in

figure 4.15 and figure 4.17 respectively. Figure 4.16 show distorted source current

waveform.

Figure 4.14 SIMULINK model of Amhara plastic pipe factory before filter

Figure 4.15 and figure 4.19 are represented source voltage of the factory. Factory source

voltage before step down is 15 kV(1.5 𝑥10 4). So these figures are shown this. The

source voltage is the same before and after compensation.

Figure 4.15 Source voltage waveform of phase ‘a’ without SAPF



Figure 4.16 Source current waveform of phase ‘a’ without SAPF

Figure 4.17 Load current waveform of phase ‘a’ without SAPF



4.7. Performance solution for Harmonic Distortion

The solutions for harmonic distortion modeling have been simulated using MATLAB

/SIMULINK/software. This modeling consists of different subsystems, like PI controller,

unit sine vector, hysteresis band current controller and VSI. Figure 4.18 is show the

integration of this system tools with factory power distribution system. Source voltage

and load current waveform are shown in figure 4.19 and figure 4.21 respectively. Figure

4.20 show the source current distortion filtered by applied shunt active power filter.

Figure 4.18 SIMULINK model of shunt active power filter for APPF

Figure 4.19 Source voltage waveform of phase ‘a’ with filter



Figure 4.20 Source current waveform of phase ‘a’ with filter

As shows figure 4.17 and figure 4.21 with and without connected shunt active power

filter the load current waveform and magnitude is like this, because of non-linear load

current consists of fundamental and harmonic components. Further the magnitude is the

same before and after compensation. From this recommended the filter is show on source

current.

Figure 4.21 Load current waveform of phase ‘a’ with filter



4.8. Result analysis and comparison of before and after SAPF implement

Below figure shows measured current harmonics distortion value before connect shunt

active power filter. For measured harmonics distortion was use frequency analyzer. The

measured value is THD 10.96%, which means above the IEEE standard.

Figure 4.22 Harmonics spectrum

Before apply power quality problem mitigation techniques or before connect SAPF was

analyzed harmonic using Fast Fourier Transform (FFT) analysis. The FFT analysis the

current THD value is 11.52% which means above the standard IEEE 519 acceptable limit

(5%). Therefore to eliminate this power quality problem used shunt active power filter.



Figure 4.23 FFT analysis of source current waveform before filtering

From the measured and simulation result it can be seen that the system having non-linear

load has the harmonic value shown in table 4.3.

Table 4.2 Current harmonic distortion before compensation

Harmonic numbers Harmonic Current (%)

5 9.8

7 4.05

THDI% 11.52



Figure 4.24 shown after filtering Fast Fourier Transform (FFT) analysis gives the current

of THD 0.21%.

Figure 4.24 FFT analysis of source current waveform after compensation

Table 4.3 Current harmonic distortion after compensation

Harmonic numbers Harmonic Current (%)

5 0.038

7 0.029

THDI% 0.21

Based on IEEE 519 standard current of THD must be below 5%. So as shown in figure

4.23 before compensation THD reach 11.52% and in figure 4.24 after compensation THD

reduced into 0.21%. Shunt active power filter effectively reduced the distortion

magnitude according to IEEE 519 standard.



Table 4.4 Comparison THDi with and without SAPF

Harmonics numbers Without SAPF With SAPF

5 9.8 0.038

7 4.05 0.029

THDi (%) 11.52 0.21

Figure 4.25 Comparison of current THD before and after compensation

4.9. Annual cost/tariff and recompense period of DVR

On this section, discussion made based on the calculation of annual cost, DVR Capacity

and Specification and EEU tariff and recompense for period of DVR. Before proceeding

different charges types such as, generation charge, demand charge, transmission charge,

distribution charge and ancillary service charges were discussed.

The types of charges that have traditionally shown up in electricity tariffs include:

Generation charge:

The price paid by consumers to cover the cost of running power plants or

purchasing power from generation companies.



Demand charges:

A special charge based on the highest amount of electricity used over the course

of a month. Imposing a demand charge requires that a utility has a special type of

electric meter that can record electricity usage in specific time increments, such as

an hour or half-hour, so that the utility is able to identify the point of peak demand

for a given month.

Transmission charge:

The price paid by consumers to cover the cost of transmission lines, or the cost of

transmission service purchased from other companies.

Distribution charge:

The price paid by consumers to cover the cost of the low-voltage distribution

systems.

Ancillary service charges:

Price paid by consumers to cover the costs of backup power and other equipment

used to keep the electric grid stable and reliable.

Annual cost of APPF

The maximum 𝑘𝑉𝐴 demand of the factory can be written as:

𝑀𝑎𝑥. 𝑘𝑉𝐴 𝑑𝑒𝑚𝑎𝑛𝑑 = 3675/0.85 = 4323.529

[𝑓𝑟𝑜𝑚 𝑜𝑙𝑑 𝐸𝐸𝑈 𝑡𝑎𝑟𝑖𝑓𝑓 𝑐𝑜𝑛𝑠𝑖𝑑𝑒𝑟, 1𝑘𝑉𝐴 = 56.04]

Factory 𝑘𝑉𝐴 demand charges can be calculated:

𝑘𝑉𝐴 𝑑𝑒𝑚𝑎𝑛𝑑 𝑐ℎ𝑎𝑟𝑔𝑒𝑠 = 4,323.529 ∗ 56.04 = 242,290.565

𝐸𝑛𝑒𝑟𝑔𝑦 𝑐𝑜𝑛𝑠𝑢𝑚𝑒𝑑 𝑝𝑒𝑟 𝑦𝑒𝑎𝑟 = 𝑀𝑎𝑥. 𝑑𝑒𝑚𝑎𝑛𝑑 ∗ 𝑝. 𝑓 ∗ 𝐻𝑜𝑢𝑟𝑠 𝑖𝑛 𝑎 𝑦𝑒𝑎𝑟

= 3675 ∗ 0.85 ∗ 8760

= 27,364,050 𝑘𝑤ℎ/𝑦𝑒𝑎𝑟

[𝐹𝑟𝑜𝑚 𝑜𝑙𝑑 𝐸𝐸𝑈 𝑡𝑎𝑟𝑖𝑓𝑓 𝑐𝑜𝑛𝑠𝑖𝑑𝑒𝑟, 1𝑘𝑤ℎ = 0.5778𝑏𝑖𝑟𝑟]

𝐸𝑛𝑒𝑟𝑔𝑦 𝑐ℎ𝑎𝑟𝑔𝑒 𝑝𝑒𝑟 𝑦𝑒𝑎𝑟 = 0.5778 ∗ 27,364,050 𝑘𝑤ℎ 𝑏𝑖𝑟𝑟

= 15,810,948.1 𝑏𝑖𝑟𝑟



𝑇𝑜𝑡𝑎𝑙 𝑎𝑛𝑛𝑢𝑎𝑙 𝑐𝑜𝑠𝑡 𝑝𝑒𝑟 𝑎𝑛𝑛𝑢𝑎𝑙 𝑏𝑖𝑙𝑙 = 𝑀𝑎𝑥. 𝑑𝑒𝑚𝑎𝑛𝑑 𝑐ℎ𝑎𝑟𝑔𝑒𝑠 + 𝑒𝑛𝑒𝑟𝑔𝑦 𝑐ℎ𝑎𝑟𝑔𝑒𝑠

= 242,290.565 + 15,810,948.1

= 16,053,238.7

Factory total annual cost per annual bill is 16, 053,238.7 birr

DVR capacity and specification

Based on selected study area (amhara plastic pipe factory) power supply system:

𝑉𝑠= 15kV

The voltage source is 15kV, then after step down by transformer the three phase voltage

is 380V. Before voltage sag occur three phase voltage is 380V, then when voltage sag

occur from 0.05 – 0.15s for duration of 0.1s voltage reduced into around 65.78%

(250V). MATLAB/ SIMULINK result show the maximum three phase voltage sag is

65%.

S= 3376.5kVA

Response time = 0.05sec

Duration of sag to protect = 0.4sec

Now solve unknown value Capacity of DVR in KVA and Required energy. It is

recommended to adopt DVR technology to compensate voltage sag and restore to 100%

of the rated value. In fact voltage sag compensator is a power conditioner that corrects

voltage sags and maintains productivity. It corrects deep sags down to 30% of nominal

voltage (70% of reduction) [52] [53]. From MATLAB/ SIMULINK result APPF voltage

sag depth is around 65%, therefore, 70% or 0.7 PU is DVR compensating voltage.

𝑇ℎ𝑒 𝑐𝑜𝑚𝑝𝑒𝑛𝑠𝑎𝑡𝑖𝑛𝑔 𝑝𝑜𝑤𝑒𝑟 = 0.7 𝑥 3376.5𝑘𝑉𝐴 = 𝟐𝟑𝟔𝟑. 𝟓𝟓 𝒌𝑽𝑨

The duration of sag to protect is 0.4 sec. so,

𝑇ℎ𝑒 𝑟𝑒𝑞𝑢𝑖𝑟𝑒𝑑 𝑒𝑛𝑒𝑟𝑔𝑦(𝐸) = 𝑝𝑜𝑤𝑒𝑟 𝑥 𝑡𝑖𝑚𝑒 = (𝑘𝑉𝐴 𝑥 𝑃𝐹)𝑥 𝑡𝑖𝑚𝑒 (3.4)

𝐸 = (2363.55 𝑥 0.85) 𝑥 0.4

𝐸 = 𝟖𝟎𝟑. 𝟔𝟎𝟕 𝐤𝐉

According to calculated compensating power, required DVR energy, and additionally

for reliability and availability of DVR select 3000 kVA and 1000 kJ for installed in the

factory low side power distribution side [53].



Cost and recompense period of DVR

In this section, discussion made on the cost and benefit analysis of installing Voltage Sag

Compensator/Dynamic Voltage Restorer (DVR) to mitigate voltage sag.

As discussed in previous chapters, voltage sages are the frequent causes of disrupted

operations for many industrial processes, especially those using modern electric

equipments that are sensitive to short duration variations. Based on this problem modern

industrial equipment affected which resulted in loss of product, clan up and restarting the

processes. Tripping electronic control devices may cause not only the current production

presently but also the future production, which eventually causes substantial revenue loss.

The recommend solution to address this problem is to install voltage sag compensator

(VSC)/ Dynamic Voltage Restorer (DVR) on important loads [52].

𝐶𝑉𝑆𝐶 = 𝐶𝐷𝑉𝑅 = 𝑇𝑝𝑎𝑦.𝑏𝑎𝑐𝑘 ∗ 𝑁𝑉.𝑆 ∗ 𝐶𝑉.𝑆

Where:

𝐶𝑉𝑆𝐶 = 𝐶𝐷𝑉𝑅: Cost of voltage sag compensator

𝑇𝑝𝑎𝑦.𝑏𝑎𝑐𝑘(𝑦𝑒𝑎𝑟): The payback time for the investment

𝐶𝑉.𝑆: Cost of a production interruption with the cause of voltage sag

𝑁𝑉.𝑆: Number of a production interruption with the cause of voltage sag

Then, cost of DVR is 300 $/kVA [53]

The cost of voltage sag, 𝐶𝑉.𝑆 at APPF is $1123/year, and by taking the upper limit of the

number of voltage sag occurrence, 𝑁𝑉.𝑆is 56/year.

𝐶𝐷𝑉𝑅 = 1123 $ 𝑥 56 𝑥 5 𝑦𝑒𝑎𝑟𝑠

= 314,440$

So the payback period will be,

𝑇𝑝𝑎𝑦𝑏𝑎𝑐𝑘 =𝐶𝐷𝑉𝑅

𝐶𝑉𝑆 ∗ 𝑁𝑉𝑆 =

314,440$

1123$ ∗ 56/𝑦𝑒𝑎𝑟 = 5 years

Since the average life time of the DVR is about 15 years [53], the solution is very

economical and feasible.



CHAPTER FIVE

5. CONCLUSIONS AND RECOMMENDATIONS

5.1. Conclusions

The aim of this research was to investigate the power quality problems in the Ethiopian

industries taking Amhara plastic pipe factory as a case study. The main objective is to

assess the existing power quality problems, associated power distribution system, and to

compare with IEEE standard values. Moreover, the research aims to model mitigation

techniques, based on the results of the power quality assessment carried out at APPF.

Based on the results of the study, the following major conclusions are drawn.

The modeling and analysis of APPF power distribution system with controller have been

done using MATLAB/SIMULINK software. The modeling of DVR is developed and

simulation results of the system with and without DVR where carried out due to the

occurrence faults.

The selected control system is based on dqo technique which is simple control algorithm.

Supply voltage is compared with reference voltage to get error signal which is given to

the gate pulse generation circuit as a reference sine wave that is compared with carrier

signal to get pulses for inverter.

Phase Locked Loop (PLL) circuit one of the most important element use to extract angle

from supply voltage for using at supply of any frequency the error signals will be

synchronized supply frequency.

The simulation result of this thesis depicts that DVR provides better response to protect

voltage sage problem occurs on sensitive loads. The cost and recompense period of DVR

results confirm that DVR has relatively low cost, small in size and fast dynamic response

time. The three phases to ground fault is occurred at distribution line and voltage sage

was occurred around 65.78% rms. When DVR is connected, the voltage variation is

solved and acceptable by IEEE standard.



The THD of the factory is 11.52% indicating it is, beyond the IEEE 519-1992 standard

(i.e. 5%). However, when shunt active power filter is connected, the THD reduced from

11.52% to 0.21% implying it fits the acceptable IEEE 519-1992 standard.

Shunt active power filters is connected in parallel to power systems; therefore, it can

operate as voltage sources. The voltage source inverter is controlled to inject the

compensation currents into the system. The control is based on the reference currents

calculated by control strategies implemented. The filter is operated in such a way that the

source supplies only the fundamental current and it supplies the harmonic current to the

system. It, also cancels the harmonic currents produced by the non-linear load.

5.2. Recommendations

Based on the results found in this thesis, it is recommended that amhara plastic pipe

factory should consider using the above power quality problem mitigation techniques.

These are Dynamic Voltage Restorer and Shunt Active Power Filter. By using these

power quality mitigation techniques, the factory can avoid the damage of information

technology equipments like microprocessor based control system personal computer,

programmable logic controls, adjustable speed drives etc and other important equipment.

Furthermore, the mitigation techniques can control the factory’s production process

stoppage, trip contactors and electromechanical relays, and then disconnection and loss of

efficiency in electrical rotating machines, motors burnout and cable insulation damage.

This eventually could improve profitability, productivity and increase the efficiency and

performance of factory equipments.

6.3. Future Work

In this thesis, the mitigation of power quality problem techniques is implemented by

using only two techniques namely Dynamic Voltage Restorer and Shunt Active Power

Filter. Moreover, the study used different controllers like PI controller. Future research

work should consider other mitigation measure techniques alone or together with DVR

and APF in order to improve more the power quality of the factory.



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APPENDIX

APPENDIX A: Factory single line Load flow analysis diagram

Figure A.1: Result of Load flow Analysis



APPENDIX B: Total electrical load of APPF

Table B1: Total electrical load of the factory

Table B2: Load Current

Phase

Load current (A)

Phase a 1234

Phase b 1309

Phase c 1480

Production

lines

Resistive

load 1

(unity)

AC

drive

loads

(0.95-

0.97)

Compe

nsated

loads

Motor

(0.7-

0.85)

Dc drives

(0.4-

0.75)

compre

ssor ,

fans

and

pumps

(0.75-

0.8)

Pups for

Spraying

(0.6-

0.65)

Non

Compensa

ted loads

Idle

loads

UPVC line 1 80.38 9.9 90.28 97.16 110 35.75 37 356.69 13.5

UPVC line 2 44.83 9.9 54.73 92.23 110 24.25 33 300.71 13.5

UPVC line 3 27.68 6.25 33.93 94.11 55.022 15.9 33 224.61 7.25

UPVC line 4 12.5 46.15 58.65 92.11 0 11.15 16.9 165.31 13.5

HDPE line 5 8.99 35.8 44.79 9.235 75 9.65 33 159.67 12

HDPE line 6 27.37 1.1 28.47 11.685 160 12.48 33 233.63 12

HDPE line 7 27.13 23.4 50.53 11.25 110.022 19.25 33 212.06 12

HDPE line 8 15 60.4 75.4 89.35 55.022 15.45 33 256.222 12

Geo membrane

9

73.85 70 143.85 32.9 352.47 27.95 33 568.82 221.35

Green sheet 10 117 780.4 897.4 41.1 15.4 5.75 0 953.65 6

Flat hose 11 4 56.4 60.4 5.335 0 0 1 63.735 3

Accessories 12 16 33.35 49.35 639.95 0 7.5 5.5 375.825 326.47

Total 454.73 1133.05 1587.78 1089.1 1027.54 332.385 285.9 3870.96 431.22



Table B3: Squeezed factory load

Production lines

Resistive load

1(unity)

AC drive loads 0.97

Motor 0.85

Dc drives

0.7

compressor ,fans and

pumps 0.8

Pups for

Spraying

0.65

IDLE loads 0.85

Sub Total With idle

loads

Sub Total

Without idle

loads

KW 454.73 1133.1 1089. 1027.5 332.3 285.9 431.2 4753.9 4322.7

KVA 454.73 1168.1 1281.3 1468 415.5 440 507.2 5734.8 5227.6

KW x 386.5 963.1 925.70 873.40 282.53 243.01 366.5 3917.26 3674.24

KVA x 328.5 992.9 1089.1 1247.8 353.17 374 431.1 4759.47 4385.47

KVAR 0 241 573.8 891.17 212 284.3 227 2703.26 2394.21

Table B4: Electrical quantities of each load

Production lines

Active power

(kW)

Reactive power

(kVAR)

Voltage

(kV)

Current

(kA)

Apparent power

(kVA)

UPVC line 1 357 221.24 0.4 1050 420

UPVC line 2 300 185.92 0.4 882.3 352.9

UPVC line 3 225 139.44 0.4 661.76 264.7

UPVC line 4 165 102.25 0.4 485.29 194.11

HDPE line 5 160 99.15 0.4 470.58 188.23

HDPE line 6 234 145.02 0.4 688.23 275.29

HDPE line 7 212 131.38 0.4 623.52 249.41

HDPE line 8 256 158.65 0.4 752.94 301.17

Geo membrane 9 569 352.6 0.4 1673.5 669.41

Green sheet 10 953 590.6 0.4 2802.9 1121.94

Flat hose 11 63.73 39.49 0.4 187.4 74.97

Accessories 12 370.82 232.9 0.4 1105.3 442.14



Table B5: Exist Load Transformer Rating

Voltage

(kV)

Apparent

power (kVA)

Power

factor

Active Power

(kW)

Reactive Power

(kVAR)

Transformer -1 15/0.4 1250 0.85 1000 619.7

Transformer -2 15/0.4 800 0.85 640 396.6

Transformer -3 15/0.4 800 0.85 640 396.6

Table B6: Voltage Unbalance in factory

Voltages Measured Values in (V)

Phase 1 to Neutral (V1 to N) 225.93



Phase to Phase Voltage Measured Values in (V)

V12 389.95

V13 375.67

V31 381.24

Table B7: Typical Un-improve power factor by Equipment

Equipment Power Factor Power factor

Air Compressor & Pumps (external Motors) 75-80

Hermetic Motors (compressors) 50-80

Arc Welding 35-60

Resistance Welding 40-60

Machining 40-65

Arc Furnaces 75-90

Induction Furnaces (60Hz) 100

Standard Stamping 60-70

High Speed Stamping 45-60

Spraying 60-65

Industrial Heating With resistance, as in ovens or dryers, the

power factor is often closed to

100%.

Welding Electric arc welders generally have a low power factor,

around Other types of machinery or equipment those are likely

to have a low power factor include

60%.



Table B8: Shows the typical power factors of some electrical equipment

Load power factor

Transformers (no load condition) 0.1÷0.15

Motor 0.7÷0.85

Metal working apparatuses:

- Arc welding

- Arc welding compensated

- Resistance welding:

-Arc melting furnace

0.35÷0.6

0.7÷0.8

0.4÷0.6

0.75÷0.9

Fluorescent lamps

-compensated

-uncompensated

0.9

0.4÷0.6

AC DC converters 0.6÷0.95

DC drives 0.4÷0.75

AC drives 0.95÷0.97

Resistive load 1

Table B9: Shows the variation of the transmissible power for MV/LV three-phase

transformers as a function of the cos φ of the load

Power of the

transformer[kVA]

Power of the transformer[kW][cos φ]

0.5 0.6 0.7 0.8 0.9 1

63 32 38 44 50 57 63

100 50 60 70 80 90 100

160 80 96 112 128 144 160

125 63 75 88 100 113 125

200 100 120 140 160 180 200

250 125 150 175 200 225 250

315 185 189 221 252 284 315

400 200 240 280 320 360 400

630 315 378 441 504 567 630

800 400 480 560 640 720 800

1000 500 600 700 800 900 1000

1250 625 750 875 1000 1125 1250



Table B10: Current carrying capacity I/0 of copper single-core cables on perforated

tray

S [mm2] Cu I [A]

XLPE/EPR PVC

25 141 114

35 176 143

50 216 174

70 279 225

95 342 275

120 400 321

150 464 372

185 533 427

240 634 507

300 736 587

500 998 789

630 1151 905

Table B11: maximum compensation of reactive energy (kVAR) at the terminals of

LV asynchronous motors

Maximum compensation of reactive energy (kVAR)

LV motor nominal power (KW)

Number of pairs of poles

1 2 2 2 3 4

22 6 8 9 10

30 7.5 10 11 12.5

37 9 11 12.5 16

45 11 13 14 17

55 13 17 18 21

75 17 22 25 28

90 20 25 25 30

110 24 29 33 37

132 31 36 38 43

160 35 41 44 52

200 43 47 53 61

250 52 57 63 71

280 57 63 70 79

355 67 76 86 98

400 78 82 97 106

450 87 93 107 117



Table B 12: Load survey of Production Line one Load Type

No. Location Nxwxn

(N)Repetition,(W) wattage (n) no. Ofw/circle

KVA

Resistive load power (KW)

compensated

(KW)

Non compen sated

(KW)

3-phase Ampere (A)

1-phase Ampere (A)

Power Factor

MIXER MACHINE

1. Hot mixer motor 1x47/67 67 120

2. Cold mixer motor 1x11x1 11 22.5 0.84

3. Sucker Motor 1x2.2x1 2.2 5.6 0.81

EXTRUSSION MACHINE

4. Feed motor 1x1.5x1 1.5 3.7

5. Extruder main DC motor 1x110x1 110 275 0.79

6. Main DC motor cooling fan 1x3x1 3 6.4 0.87

7. Barrel cooling Fans 5 consecutive 5x0.55x1 2.75 6.75

8. barrel Heaters- 1 (ø375x215) 1x3.75x1 3.75 7.5

9. barrel Heaters- 2 (ø340x390 1x10x1 10 20

10. barrel Heaters - 3 (ø340x380 1x10x1 10 20

11. barrel Heaters- 4 ( ø340x320 1x8.5x1 8.5 17

12. barrel Heaters- 5 (ø280x260 1x5.3x1 5.3 10.6

13. barrel Heaters- 6 ø280x240 1x5.3x1 5.3 10.6

14. Die -core Heaters- (220x160)x1pcs 1x2.5x1 2.5 5

MOLD (DIE ) MACHINE

15. Die -Heaters-1- (ø 450x136)x1 pcs 1x3.6x1 3.6 7.2

16. Die -Heaters-2,3,- (ø 730x110)x4 2x1.5x4 12 24

17. Die -Heaters-4,5,6, - (ø 850x125)x2 3x3.8x2 22.8 45.6

18. Die -Heaters-7,8- (ø 1040x170)x2 2x6.4x2 25.6 51.2

19. Die -Heaters--9-(ø 1040x120)x2pcs 1x4.5x2 9 18

20. Die -Heaters-10,11- (ø 910x150)x2 2x5x2 20 40

21. Die -Heaters- 12- (ø 720x123)x1 pcs 1x5.6x1 5.6 11.2

22. Die -Heaters-13-(ø 660x235)x4 pcs 1x2.8x4 11.2 22.4

23. Die -Heaters-14- (ø 910x150)x2 pcs 1x5x2 10 20

24. Die -Heaters-15- (ø 710x230)x4 pcs 1x3x4 12 24


26. Die -Heaters-17,18- ( ø 570x260)x4 2x2.7x4 21.6 43.2

VACUUM TANK MACHINE

27. Vacuum pump motor 2pcs 7.5x2 15 24

28. Water pump motor 2pcs 7.5x2 15 30 0.88

29. Vacuum screw motor 1x1 1 2

COOLING TANK MACHINE 1&2

30. 1st cooling Water pump motor 2pcs 5.5x2 11 22.2 0.88

31. 2nd cooling Water pump motor 2pcs 5.5x2 11 22.2 0.88

HALL OFF MACHINE

32. Hall Off AC motor 4pcs 4x1.1 4.4 10.4

33. Haul off adjuster 2x0.75 1.5 4.06 0.75

CUTTER MACHINE

34. Cutter feed & retract x1 pcs 1.1 1.1 2.2 0.78

35. Cutter -rotation x1 pcs 3 3 6.8 0.87

36. Cutter- revolution x1 pcs 4 4 8

BELLING MACHINE 1&2

37. Heater rode 8x2x2 32 64

38. Pipe puller 2x2.2x1 8.8 17.6

39. Fro and back rotation 2x0.35x1 0.7 1.15

40. Oil pump motor 2x7.5x1 15 15

41. Pipe rotation motor 4x0.09x 0.36 0.72

Sub Total load 241.15/3 9.9 278.41 604.28 481.9

Total load 358.69 =80.38

Speed variable load(feeder, dc motor 110

compensated (heaters,+ ac drives 80.38 +9.9=90.28

Idle loads(pump1/2of belling) No.30,32 11+1+1.5=13.5

Variable loads(mixer, sucker, cutter), fan, vacuum, &cooling pump, haul off)

67+11+ 2.2+3+2.75+15+11+1.1+3+8.8+0.7+15+0.36 =140.91



Table B 13: Load survey of Production Line two

Load Type

No. Location Nxwxn K

V

A

Resistive

load

power

(KW)

compen

sated

(KW)

Non

compens

ated

(KW)

3-phase

Ampere

(A)

1-phase

Ampere

(A)

Power

Factor

MIXER MACHINE

1. Hot mixer motor (47/67KW) 67 120 2. Cold mixer motor 11 11 22.5 0.84

3. Sucker Motor 2.2 2.2 5.6 0.81 EXTRUSSION MACHINE

4. Feed motor 1.5 3.7 5. Extruder main DC motor 110 275 0.79 6. Main motor cooling fan 3 6.4 0.87

7. Barrel cooling Fans 5 consecutive 1.35A

5x0.55x1 2.75 6.75

8. barrel Heaters- 1 (ø375x215) 1x3.75x1 3.75 7.5

9. barrel Heaters- 2 (ø340x390 1x10x1 10 20

10. barrel Heaters - 3 (ø340x380 1x10x1 10 20 11. barrel Heaters- 4 ( ø340x320 1x8.5x1 8.5 17

12. barrel Heaters- 5 (ø280x260 1x5.3x1 5.3 10.6 13. barrel Heaters- 6 ø280x240 1x5.3x1 5.3 10.6 14. Die -core Heaters- (220x160)x1pcs 1x2.5x1 2.5 5

MOLD (DIE ) MACHINE 15. Die -Heaters-1- (ø 390x130)x1 pcs 1x3.5x1 3.5 7.2

16. Die -Heaters-2,3- (ø 740x232)x4 p 1x4.8x2 9.6 24 17. Die -Heaters-4- (ø 740x100)x2 pcs 2x6.2x2 24.8 45.6


19. Die -Heaters-6- (ø320x152)x4pcs 1x3.5x4 14 18 20. Die -Heaters-7- (ø 470x140)x4pcs 2x4.8x4 19.2 40

VACUUM TANK MACHINE 21. Vacuum pump motor 2pcs 5.5x2 11 22.2

22. Water pump motor 2pcs 5.5x2 11 30 0.88 23. Vacuum screw motor 1x1 1 2

COOLING TANK MACHINE 24. 1st cooling Water pump motor 2pcs 5.5x2 11 22.2 0.88


HALL OFF MACHINE 26. Hall Off AC motor 4pcs 4x1.1 4.4 10.4


CUTTER MACHINE

28. Cutter feed & retract 1x1.1 1.1 2.2 0.78 29. Cutter -rotation 1x3 3 6.8 0.87

30. Cutter- revolution AC motor 1x4 4 8

BELLING MACHINE

31. Heater rode 4 x1.5 6 12 32. Pipe puller 1x2.2 4.4

33. Fro and back rotation 1x0.35 0.35 1.12 34. Oil pump motor 1x7.5 7.5 15

35. Pipe rotation motor 2x0.09 0.18 0.64

Sub Total 134.5/3=44.83

9.9 257.98 873.47 288.7

Total 308.713

Speed variable load dc motor 110

compensated (heaters, ac drives) 44.83 +9.9=54.73

Idle loads pump1/2of belling 11+1.5=12.5

Variable loads mixer, sucker, cutter, fan, vacuum, &cooling pump, haul off

67+11+ 2.2+3+2.75+11+11+1.1+3+4.4+0.35+7.5+0.18 =124.48



Table B 14: Load survey of Production Line three

Load Type

No. Location Nxwxn ( KVA Resistive load power (KW)

Compensated(KW)

Non Compensated(KW)

3-phase Ampere (A)

1-phase Ampere (A)

Power Factor

MIXER MACHINE

1. Hot mixer motor (47/67KW) 67 120

2. Cold mixer motor 11 11 22.5 0.84

3. Sucker Motor 2.2 2.2 5.6 0.81

EXTRUSSION MACHINE

4. Feed motor 0.75 2.03

5. Extruder main DC motor 55 275 0.79

6. Taco generator 0.022 0.2

7. Main motor cooling fan 1.1 2.6 0.84

8. Barrel cooling ,Fans 3consecutive 1.2A 3x0.55x1 2.75 3.6

9. Barrel Heaters- 1 (ø320x300) 1x5x1 5 7.5

10. Barrel Heaters- 2 (ø290x390) 1x10x1 10 20

11. Barrel Heaters - 3 (ø260x380) 1x10x1 10 20

12. Barrel Heaters- 4 ( ø240x320) 1x8.5x1 8.5 17

13. Die -core Heaters- (210x160)x1pcs 1x2x1 2 5

MOLD (DIE ) MACHINE

14. Die -Heaters-1- (ø 330x115) x1 1x2.6x1 2.6 7.2

15. Die -Heaters-2- (ø 520x120) x1 1x4.5x1 12 24


17. Die -Heaters-, 4- (ø 520x175)x1 1x6.5x1 6.5 51.2

18. Die -Heaters -,5-(ø 436x95)x1pcs 1x4.5x1 4.5 18

19. Die -Heaters-,6,7- (ø 310x110)x2 2x2.5x1 5 40


21. Die -Heaters-9-(ø 296x80)x1pcs 1x1.6x1 1.6 22.4

22. Die -Heaters-10- (ø 95x150)x1 pcs 1x0.65x1 0.65 20



25. Die-Heaters-13- ( ø 296x110)x1pcs 1x2.5x1 2.5 43.2

VACUUM TANK MACHINE

26. Vacuum pump motor 1pcs 4 4 8.2 0.88

27. Vacuum screw 1pcs 0.37 0.37 1.12

28. Water pump motor 1pcs 5.5 5.5 10.9 0.88


COOLING TANK MACHINE

30. 1st cooling Water pump motor 1 5.5 5.5 11.1 0.88

31. 2nd cooling Water pump motor 1 5.5 5.5 11.1 0.88

HALL OFF MACHINE

32. Hall Off AC motor 4pcs 4x1.1 4.4 10.4

33. Haul off adjuster 1pcs 0.75 0.75 1.9 0.75

CUTTER MACHINE

34. Cutter feed & retract 0.35 0.35 1.12 0.78

35. Cutter -rotation 1.5 1.5 3.67 0.87

36. Cutter- revolution 1.5 1.5 3.7

BELLING MACHINE 1&2

37. Heater rode 4x1.5 6 12

38. Tow/Pipe puller motor 1x2.2 4.4

39. Oil pump motor 1pcs 1.5 1.5 3.7

40. Fro and back rotation motor 1pcs 1x0.09 0.18 0.64

41. Pipe rotation motor 1pcs 2x0.09 0.18 0.64

Sub total 83.05/3=27.68 6.25 168.752 499.72 408.7

Total 202.713

Speed variable load feeder, dc motor 55

compensated (heaters, ac drives) 27.68 +5.5=33.18

Idle loads pump1/2of belling 5.5+0.75=6.25


67+11+ 2.2+1.1+2.75+4+0.37+5.5+5.5+0.35+1.5+4.4+1.5+0.18+0.18 =107.53



Table B 15: Load survey of Production Line four

Load Type

No. Location Nxwxn ( KVA)


Compensated (KW)

Non Compensated (KW)

3-phase Ampere (A)

1-phase Ampere (A)

Power Factor

MIXER MACHINE

1. Hot mixer motor 47/67 67 120 2. Cold mixer motor 11 11 22.5 0.84

3. Sucker Motor 2.2 2.2 4.7 0.81 EXTRUSSION MACHINE

4. Barrel cooling Fans 3 consecutive 1.35A 3x0.55x1 1.65 3.3

5. Feed motor 0.75 0.75 2.03 6. Extruder main AC motor 37 37 75 0.79

7. Barrel Heaters- 1 (ø265x290) 1pcs 1x4.5x1 4.5 10 8. Barrel Heaters- 2 (ø230x160) 1pcs 1x4x1 4 8.4

9. Barrel Heaters - 3 (ø230x245) 1pcs 1x5x1 5 11 10. Barrel Heaters- 4 ( ø190x240) 1pcs 1x4x1 4 8.4

11. Die -core Heaters- (220x120) 1pcs 1x2x1 2 5

MOLD (DIE ) MACHINE

12. Die -Heaters -1- (ø 210x120)x1 pcs 1x2x1 2 4.2

13. Die -Heaters -2, 3- (ø 215x115)x1 pcs 2x3.4x1 6.8 13.8 14. Die -Heaters -4,5,- (ø 80x65)x1 pcs 2x0.4x1 1.8 45.6

15. Die -Heaters - 6, 7- (ø176x106)x1 pcs 2x0.3x1 0.6 51.2 16. Die -Heaters -8,9- (ø 196x80)x1pcs 2x1.1x1 2.2 18

17. Die -Heaters-10,11- (ø 196x100)x1 pcs 2x1.3x1 2.6 40

VACUUM TANK MACHINE

18. Vacuum pump motor 1pcs 4x2 8 16.4 19. Water pump motor 1pcs 2.2x2 4.4 9.4 0.88





HALL OFF MACHINE

23. Hall Off motor 4pcs 4x1.1 4.4 10.4 24. Haul off adjuster 2x0.75 1.5 4.06 0.75

CUTTER MACHINE 25. Cutter feed & retract 1x1.1 1.1 2.2 0.78

26. Cutter -rotation 1x3 3 6.8 0.87 27. Cutter- revolution 1x4 4 8

BELLING MACHINE 28. Tow/ Pipe puller motor 1x2.2 4.4

29. Heater rode 4x0.5 2 4

30. Oil pump motor 1.5 1.5 3.7 31. Fro and back rotation motor 1pcs 1x0.09 0.18 0.64

32. Pipe rotation motor 1pcs 2x0.09 0.18 0.64

Subtotal 37.5/3=12.5

46.15 116.06 259.17 294.6

Total 182.2

compensated (heaters, ac drives) 12.5.5+46.15=58.7

Idle loads pump1/2of belling 1+5.5+0.75 = 7.25


67+11+ 2.2+1.65+8+4.4+11+1,1+3+4.4+1.5+0.18+0.18 =116.25



Table B 16: Load survey of Production Line five

Load Type

No. Location Nxwxn K V A

Resistive load Active power (KW)

Compensated (KW)


3-phase Ampere (A)

1-phase Ampere (A)

Power Factor

MIXER MACHINE

2. Stripper main motor 1pcs 0.55 0.55 1.15

3. Stripper fan motor 1pcs 0.085 0.085 0.19

4. Stripper heater 4pcs 0.18 0.72 1.5 EXTRUSSION MACHINE

4. Auto loader /Feed motor 3 3 6 0.81

5. Extruder main DC motor 75 75 188 0.79

6. Main DC motor cooling fan 3 6.4 0.87

7. Barrel cooling Fans 4 consecutive 1.35A

4x0.55x1 2.25 6.75

8. Barrel Heaters- 1,2,3,4 (ø160x350) 4x3.5x1 14 28

9. Die -core Heaters- (120x80)x1pcs 1x0.8x1 0.8 1.6

MOLD (DIE ) MACHINE

10. Die -Heaters-1,2- (ø 220x45) x2pcs 2x0.95 1.9 4

11. Die -Heaters-3- (ø 110x55) x1 pcs 1x0.65 0.65 1.5


13. Die -Heaters-4,5,6- (ø 280x130)x3 3x2.8x1 7.4 15

14. Die -Heaters -5-(ø 120x80)x1pcs 1x0.8x1 0.8 1.6

VACUUM TANK MACHINE

15. Vacuum pump motor 2pcs 2.2x2 4.4 8.8 0.88

16. Water pump motor 2pcs 5.5x2 11 24




HALL OFF MACHINE

19. Hall Off AC motor 4pcs 4x2.2 8.8 18


CUTTER MACHINE

21. Cutter feed & retract motor 1.1 1.1 2.2 0.78

22. Cutter -rotation motor 3 3 6.8 0.87

23. Cutter- revolution AC motor 4 4 8

WINDER MACHINE

24. Winder motor 2x5.5 11 22.2

Subtotal 26.97/3=9 26.8 82.85 348.45 53.2

Total 149.685


compensated (heaters, ac drives) 9+ 3+8.8+4+11 =35.8

Idle loads pump1/2of belling 11+1=12


0.55+0.085+3+2.25+4.4+11+1.5+1.1+3 =26.885



Table B 17: Load survey of Production Line six

Load Type

No. Location Nxwxn

KVA)


Compensated (KW)


3-phase Ampere (A)

1-phase Ampere (A)

Power Factor

MIXER MACHINE

42. Mixer motor 1pcs 3 3 6 43. Stripper main motor 1pcs 1.1 1.1 2.5

44. Stripper fan motor 1pcs 0.085 0.085

0.19

45. Stripper heater 4pcs 0.18 0.72 1.5 EXTRUSSION MACHINE

46. Autoloader motor 1.5 3.7 47. Extruder main DC motor 160 397 0.79

48. Main motor cooling fan 3 6.4 0.87 49. Barrel cooling Fans 4 consecutive

1.4A 4x0.37x1

1.48 5.6

50. Barrel Heaters- 1 (ø160x565) 1 1x8.5x4 34 70


MOLD (DIE ) MACHINE


53. Die -Heaters-2,3,- (ø 330x75)x2 pcs 2x2.4x2 9.6 24 54. Die -Heaters-4,5,6, - (ø 530x75)x1 3x2.15x

2 13 26

55. Die -Heaters-7,8- (ø 400x75)x2 pcs 2x1.4x2 9.6 19.2

56. Die -Heaters-9-(ø 510x110)x2pcs 1x2.75x2

4.5 9


58. Die -Heaters- 12- (ø 430x80)x1 pcs 1x1.5x1 1.5 3

VACUUM TANK MACHINE

59. Vacuum pump motor 2pcs 4x2 8 16 0.88 60. Water pump motor 2pcs 5.5x2 11 24



62. 1st cooling Water pump motor 2pcs 5.5x2 11 22.2 0.88 63. 2nd cooling Water pump motor 2pcs 5.5x2 11 22.2 0.88

HALL OFF MACHINE 64. Hall Off motor 4pcs 4x2.2 8.8 17


CUTTER MACHINE 66. Cutter feed & retract 1.5 1.5 3 0.78

67. Cutter -rotation 3 3 6 0.87 68. Cutter- revolution 1.1 1.1 2.6

Subtotal 82.12/3=27.37

9.9 225.965

538.45 171.3

Total 259.7


compensated (heaters, ac drives) 27.37+8.8 +1.1=37.27



3+1.1+0.85+5+3+1.48+8+11+11+1.5+1.5+3 =50.43



Table B 18: Load survey of Production Line seven

Load Type


Resistive load Active power (Kw)

Compensated (KW)


3-phase Ampere (A)

1-phase Ampere (A)

Power Factor

MIXER MACHINE

1. Mixer motor 1pcs 1x3x1 3 6 2. Stripper main motor 1pcs 1x1.1x1 1.1 2.5

3. Stripper fan motor 1pcs 1x0.085x1 0.085

0.19

4. Stripper heater 4pcs 1x0.18x1 0.72

1.5

EXTRUSSION MACHINE 5. Feed motor 1x1.5x1 1.5 3.7

6. Extruder main DC motor 1x110x1 110 275 0.79 7. Taco generator 0.022x1 0.0

22 0.2

8. Main motor cooling fan 1x3x1 3 6.4 0.87

9. Barrel cooling Fans 5 consecutive 1.35A 5x0.55x1 2.75

6.75

10. Barrel Heaters- 1 (ø160x565) 1 1x8.5x4 34 70 11. Die -core Heaters- (120x80)x2pcs 1x0.8x2 1.6 3.2

MOLD (DIE ) MACHINE 12. Die -Heaters-1- (ø 245x110)x1 pcs 1x2.4x1 2.4 5

13. Die -Heaters-2,3,- (ø 330x75)x2 pcs 2x2.4x2 9.6 24 14. Die -Heaters-4,5,6, - (ø 530x75)x1 3x2.15x2 13 26

15. Die -Heaters-7,8- (ø 400x75)x2 pcs 2x1.4x2 9.6 19.2 16. Die -Heaters-9-(ø 510x110)x2pcs 1x2.75x2 4.5 9


18. Die -Heaters- 12- (ø 430x80)x1 pcs 1x1.5x1 1.5 3

VACUUM TANK MACHINE

19. Vacuum pump motor 2pcs 4x2 8 16 20. Water pump motor 2pcs 5.5x2 11 22.2 0.88



22. 1st cooling Water pump motor 2pcs 5.5x2 11 22.2 0.88 23. 2nd cooling Water pump motor 2pcs 5.5x2 11 22.2 0.88

HALL OFF MACHINE 24. Hall Off motor 4pcs 4x1.1 4.4 10.4


CUTTER MACHINE 26. Cutter feed & retract 0.35 0.3

5 1.12 0.78

27. Cutter -rotation 3 6.8 0.87

28. Cutter- revolution AC motor 4 4 8

WINDER MACHINE

29. AC Winder 2x7.5x1 15 30 0.84

Subtotal 81.4./3=27.13

23.4

168.027

445.22

417.9

Total 201.83


compensated (heaters, ac drives) 27.13+ 23.4 =32.4



3+1.1+0.85+1.5+2.75+1.48+8+11+11+1.5+1.5+0.35+3 =47.43



Table B 19: Load survey of production line eight

Load Type



Compensated (KW)


Ampere (A)

Power Factor

MIXER MACHINE

1. mixer motor 1.1 22.5

0.84

2. Sucker Motor 2.2 5.6 0.81 EXTRUSSION MACHINE

3. Feed motor 1.5 3.7 4. Extruder main AC motor 37 74 0.79

5. Main motor cooling fan 3 6.4 0.87

6. Barrel cooling Fans 5 consecutive 1.35A 5x0.55x1 2.75

6.75

7. Barrel Heaters- 1 (ø160x565) 1 1x2.2x4 8.8 17


9. MOLD (DIE ) MACHINE 10. Die -Heaters-1- (ø 245x110)x1 pcs 1x2.4x1 2.4 5

11. Die -Heaters-2,3,- (ø 330x75)x2 pcs 2x2.4x2 9.6 24 12. Die -Heaters-4,5,6, - (ø 530x75)x1 3x2.15x2 13 26


VACUUM TANK MACHINE 14. Vacuum pump motor 2pcs 5.5X1 5.5 24

15. Water pump motor 2pcs 1X5.5 5.5 30 0.88 16. Vacuum screw motor 1x1 1 2

COOLING TANK MACHINE 17. 1st cooling Water pump motor 2pcs 5.5x2 11 22.2 0.88


HALL OFF MACHINE

19. Hall Off motor 4pcs 4x1.1 4.4 10.4


CUTTER MACHINE

21. Cutter feed & retract 1.1 2.2 0.78 22. Cutter -rotation 3 6.8 0.87

23. Cutter- revolution 4 8

WINDING MACHINE

24. Winder 2x7.5x1 15 30 0.84

Subtotal 45/3=15

60.4 35.15 589.81 417.9

Total 122.55

compensated (heaters, ac drives) 15+ 60.4 =75.4



1.1+2.2+1.5+2.75+5.5+5.5+11+1.5+1.1+3 =35.15



Table B 20: Load survey of Production Line nine, geo membrane 0.5 mm up to 2

mm

Nxwxn Load Type

No. Location ( KVA)


Compensated (KW)


3-phase Ampere (A)

1-phase Ampere (A)

Power Factor

MIXER MACHINE 1. 1 Mixer motor 1 1x4x1 4 8 0.87 2. Sucker Motor 1 1x2.2x1 3 6 0.88

3. Blower AC motor 1,2 2x18.5x1 37 71 0.9 4. Blower AC motor 1 1x30x1 30 56.9 0.9 5. EXTRUSSION MACHINE 6. Extruder main DC motor 1 1x315x1 315 630 0.87

7. Main DC motor fan 1x3x1 3 6 0.87 8. Hydraulic Oil pump 1x3x1 3 6

9. Gear box Oil pump 1x3x1 3 6

10. Barrel cooling Fans 9 consecutive 1.5A 9x0.75x1 6.75 13.5 11. Barrel cooling Fans 2 consecutive 1.35A 2x0.55x1 2.7 6.75

12. barrel Heaters -1- (ø375x215) 11x8.5x1 3.75 7.5 13. barrel Heaters -2- (ø340x390) 2x5.8x1 10 20

MOLD (DIE ) MACHINE 14. Die lip-Heaters-1- (ø 1865x85)x12pcs 12x1x1 12 24

15. Die shell - Heaters-2,3,- (ø 1865x70)x4pcs

12x1.5x2 36 72

16. Die base bottom-Heaters-4, (ø1 850x98)x12pcs

12x1x1 12 24

17. Die bottom -Heaters-7,8- (ø 1830x ø 1500x170)x12

12x2x1 24 48

18. Die bottom -Heaters-7,8- (ø 1060x ø x400)x12pcs

12x2x1 24 48

19. Die - neck-Heaters-9-(ø 1040x120)x2pcs 1x4.5x2 9 18 20. Die-neck-Heaters-10,11- (ø

910x150)x2pcs 2x5x2 20 40

21. Adapter -Heaters- 12- (ø 720x123)x1pcs 1x5.6x1 5.6 11.2

22. Adapter -Heaters-13-(ø 660x235)x4 pcs 1x2.8x4 11.2 22.4 23. Adapter -Heaters-14- (ø 910x150)x2 pcs 1x5x2 10 20

24. Feeder-Heaters-15- (ø 710x230)x4 pcs 1x3x4 12 24 25. Feeder-Heaters-16- (ø 475x300)x4 pcs 1x2.6x4 10.4 20.4


HALL OFF MACHINE

27. Hall Off up stair DC motor 2pcs 2x11x1 22 44 0.75 28. Hall Off DC motor Taco generator 2x0.022 0.044 0.1

29. Haul off adjuster 8x2.2x1 17.6 35.2 0.75 30. Adjuster 3x0.55x1 1.75 3.55 0.78

WINDING MACHINE

31. Winder A&B DC motor 2x7.5x1 15 30 0.84 32. Winder DC motor fun 2x0.18x1 0.36 0.72

33. Winder A&B DC motor Taco generator 2x0.022 0.044 0.1 34. Roller rotation 1x0.55x1 0.55 1.15 0.84

35. Rewinder 2x1.5x1 3 6

Subtotal 221.55/3=73 70 400.798 930.97 442.7

Total 524.63


compensated (heaters, ac drives) 73.85+70 =143.85

Idle loads pump1/2of belling 17.6+1.75=18.35


4+3+3+3+6.75+2.7+22+15+0.36+0.55 =47.43



Table B 21: Production Line ten, green sheet 0.1 mm up 0.5 to mm

Load Type

No. Location Nxwxn Apparent Power ( KVA)

Resistive load Acpower (KW)

Compensated (KW)


3-phase Ampere (A)

1-phase Ampere (A)

MIXER MACHINE

1. 1 Mixer motor 1,2,3 3x3x1 9 18 0.87

2. Sucker Motor 1,2,3 3x2.2x1 6.6 6 0.88 3. Blower motor 1,2 2x22x1 44 88 0.9

4. Blower motor 1 1x37x1 37 74 0.9

EXTRUSSION MACHINE

5. Extruder main AC motor 1,2 2x200x1 400 800 0.87 6. Extruder main AC motor 1 1x280x1 280 560 0.87

7. Barrel cooling Fans 5 consecutive 1.3A 29x0.75x1 2.75 6.75 8. barrel Heaters- 1 (ø375x215) 1x3.75x1 3.75 7.5 9. barrel Heaters- 2 (ø340x390) 1x10x1 10 20

MOLD (DIE ) MACHINE 10. Die lip-Heaters-1÷18- (ø 2090x85)x18pcs 18x1x1 18 36

11. Die shell - Heaters-1÷54- (ø 2000x150)x54 54x1.5x1 81 162 12. Die bottom-Heaters-1÷18-(ø1985x98)x18 18x1x1 18 36

13. Die bottom -Heaters-1÷12-(ø 1965x ø 1465x250)x12

12x3x1 3.6 7.2

14. Die - neck-Heaters-1,2-(ø 814x55)x2pcs 1x2.2x2 4.4 18

15. Die -Heaters-1÷4- (ø 984x90)x2pcs 4x4x1 8 16 16. Die -Heaters-1÷4- (ø 750x ø 550x200)x4pcs 4x1.5x1 6 12

17. Die -Heaters-1÷4- (ø 880x ø 450x250)x4pcs 4x2x1 8 16 18. Die -Heaters-1÷4- (ø 1530x110)x4pcs 4x1.5x1 6 12

19. Die -Heaters-1÷4- (ø 1530x110)x4pcs 4x2x1 8 16 20. Die -Heaters-1 - ( ø 340x185)x1 pcs 1x1.6x1 1.6 3.2

21. Adapter -Heaters -1- (ø 120x200)x6pcs 6x2x1 12 24 22. Adapter -Heaters-1-(ø 160x160)x3 pcs 3x2x1 6 12

23. Adapter -Heaters-1- (ø 100x100)x1 1x0.8x1 0.8 1.6 24. Feeder-Heaters-1- (ø 216x100)x1 pcs 1x1.6x1 1.6 3.2

25. Feeder-Heaters-1- (ø 350x156)x1 pcs 1x3.2x1 6.4 12.8 26. Feeder-Heaters-1- (ø 360x50)x2x3 pcs 6x0.7x1 4.2 8.4 27. Feeder-Heaters-1- (ø 360x60)x2x3 6x0.85x1 5.1 10.2

28. Feeder -Heaters-1- ( ø 206x350)x18 18x3.4x1 61.2 122.4 29. Feeder-Heaters-1- (ø 250x350)x8 pcs 8x8.2x1 65.6 131.2

30. Feeder-Heaters-1- (ø 250x250)x2 pcs 2x5.9x1 11.8 23.6 HALL OFF MACHINE

31. Hall Off AC motor 4pcs 4x1.1 4.4 10.4 32. Haul off adjuster 8x0.75 6 12 0.75

WINDING MACHINE

33. Winder AC motor 2x7.5x1 15 30 0.84 34. Roller 1x2.2x1 22 45 0.84

35. Winder A&B DC motor 2x7.5x1 15 30 0.84 36. Winder DC motor fun 2x0.18x1 0.36 0.72

37. Winder A&B DC motor Taco generator 2x0.022 0.044 0.1 38. Roller rotation 1x0.55x1 0.55 1.15 0.84 39. Rewinder 2x1.5x

1 3 6

Subtotal 351.05/3 780.4 59.26 1677.18 717.3

Total 962.66 =117


compensated (heaters, ac drives) 44+37+400+280+4.4+15=780.4 +117=

Idle loads pump1/2of belling 6


9+6.6+2.75+22+15+0.36+0.55+3=59.26



Table B 22: Load survey of Production Line eleven, flat hose

Load Type

No. Location Nxwxn KVA


Compensated (KW)


Ampere (A)

Power Factor

EXTRUSSION MACHINE

25. Material sucker/ Feed motor 0.18 0.4 26. Material heater blower motor 0.155 0.15

5 0.3

27. Extruder main AC motor 37 37 72 0.79

28. Main motor cooling fan 3 3 6.4 0.87 29. Barrel cooling Fans 4 consecutive 1.35A 4x0.25x1 1 2.15

30. Barrel Heaters- 1 (ø375x215) 12 pcs 12x0.4x1 4.8 9.6

31. Barrel screen Heaters- 2 (ø340x390) 4x0.3x1 1.2 20 32. Material Heaters - 3 (ø340x380 1x4x1 4 8

33. Fiber adjuster motor 2x1.5 3 6

MOLD (DIE ) MACHINE

34. Die -Heaters-1- (ø 450x136)x1 pcs 1x4x2 8 8 35. Die -Heaters-2,3,- (ø 730x110)x4 pcs 2x2.4x1 2.4 4.8

WEAVING MACHINE 36. Weaving motor 4pcs 4x1.1 4.4 10.4

COOLING TANK MACHINE 37. 1st cooling Water pump motor 2pcs 1x1 1 2 0.88

WINDING MACHINE

38. Winder motor 2x7.5x1 1 30 0.84 39. Roller 1x1x1 1 45 0.84

Subtotal 12/3 56.4 6.335

233.91 37.6

Total 49.4


compensated (heaters, ac drives) 37+4.4+1=42.4+4=46.4

Idle loads pump1/2of belling 3


0.18+0.155+3+1+1+1=6.335



Table B 23 Production Line twelve: Accessories and Recycle machines

Load Type

No. Location Nxwxn KVA


Compensated (KW)


3-phase Ampere (A)

1-phase Ampere (A)

Power Factor

COMPRESSOR MACHINE 1. 1

Compressor motor 1,2 2x55x1 110 220 0.87

2. Compressor fan Motor 1,2 2x2.2x1 4.4 8.8 0.88 CHILLER MACHINE

3. Factory Inlet pump motor 1,2,3 3x11x1 33 66 0. 78

4. Condenser inlet pump motor 1,2,3

3x7.5x1 22.5 45 0. 78

5. cooling tower inlet pump motor 1.2,3

3x5x1 15 30

6. cooling tower fan motor 1.2,3 3x3x1 9 18

CRUSHER MACHINE

7. UPVC hammer crusher main motor

1x45x1 45 90

8. UPVC hammer crusher oil pump

1x3x1 3 6

9. UPVC crusher 1,2 2x55x1 110 220

10. UPVC Fine crusher/miller/ 1 1x45x1 45 90

11. Fine crusher/miller/ oil pump 1x2.2x1 2.2 4.4

12. Miller blower 1x5.5x1 5.5 11

13. Milling /pulverizer/ 1,2 2x37x1 74 150

14. Milling blower 1,2 2x4x1 8 16

15. HDPE hammer crusher main motor

1x55x1 55 110

16. HDPE hammer crusher oil pump

1x3x1 3 6

17. HDPE belt conveyer 1x2.2x1 2.2 5

18. HDPE crusher 1 1x75x1 75 150

19. HDPE crusher adjuster 1x0.55x1 0.55 1.2

20. HDPE crusher screw conveyer 1,2,3,4

4x2.2x1 8.8 18

21. HDPE crusher washing 4x2.2x1 8.8 18

22. HDPE crusher dewater 1x5.5x1 5.5 12.1

23. HDPE crusher blower 1x7.5x1 7.5 14.5 0.89

24. Shower heaters 8pcs 8x3 24 48

25. Dryer heaters 8pcs 8x3 24 48

26. Factory lighting 100x1 100 200 Subtotal 48/3 100/3 652.95 1507.2 96

Total 605.85 Speed variable load feeder, dc motor 0

compensated (heaters, ac drives) 33.35+16=49.35

Idle loads pump1/2of belling 302.95


110+4.4+33+22.5+15+9+45+3+110+45+2.2+55+3+2.2+75+0.55+8.8+5.5+7.5=556.65



APPENDIX C: Electricity tariff category

Table C 1 Equivalent flat rate tariff of EEU void source specified

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