FUZZY CONTROLLER BASED DYNAMIC VOLTAGE RESTORER FOR VOLTAGE · FUZZY CONTROLLER BASED DYNAMIC...

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FUZZY CONTROLLER BASED DYNAMIC VOLTAGE RESTORER FOR VOLTAGE

FLUCTUATIONS

S. Sherine1,G.Hemavathi

2

1,2Assistant professor

Department of EEE

BIHER, BIST, Bharath University

Chennai- 600073. [email protected]

ABSTRACT

The power quality requirement is one of the

major issues for power companies and their

customers. The analysis of power disturbance

characteristics and finding solution to the

power quality problems have resulted in an

increased interest for power quality. The most

concerning disturbances affecting the quality of

the power in the distribution system are voltage

fluctuations. The DVR is used to mitigate the

voltage fluctuations on sensitive load. In this

paper Z-source inverter (ZSI) based DVR is

proposed to enhance the voltage restoration

property of the system. The ZSI uses an LC

impedance grid to couple power source to

inverter circuit and prepares the possibility of

voltage buck and boost by short circuiting the

inverter legs. Additionally a fuzzy logic control

scheme for Z source inverter based DVR is

proposed to obtain desired injecting voltage.

Modelling and simulation of the proposed DVR

is implemented in MATLAB/SIMULINK

platform

I INTRODUCTION

Modern power systems are complex

networks consisting of more number of

generating stations and load centers which are

interconnected through the power transmission

lines. [1-5]There are many issues involved here

such as maintenance of the power apparatus in

the system and maintaining the stability of the

system operation during fault condition.

The power system especially the

distribution system, have numerous non linear

loads which significantly affect the quality of

power supply.[6-11] The deviation of voltage,

current or frequency which can be described as

a power quality problems results in collapse or

incorrect operation of customer equipment

.Voltage fluctuations, flicker, harmonics

distortion, impulse transients and interruptions

are the various power quality problems

addressed in the distribution system. Of the

above power quality problems, a voltage

fluctuations disturbance poses a series threat to

the industries.[12-15] It can occur more

frequently than any other power quality

phenomenon.

Voltage sag is defined by the IEEE

1159 as the decrease in the RMS voltage level

to 10%-90% of nominal, at the power

frequency for duration of half to one minute.

Voltage swell is defined by IEEE 1159 as the

increase in the RMS voltage level to 110%-

International Journal of Pure and Applied MathematicsVolume 119 No. 12 2018, 8241-8253ISSN: 1314-3395 (on-line version)url: http://www.ijpam.euSpecial Issue ijpam.eu

8241

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180% of nominal,[16-19] at the power

frequency for duration of half cycles to one

minute.

Dynamic voltage restorer (DVR) is one

of the power electronic devices connected in

series to the distribution system. It compensates

the voltage disturbances by injecting the

voltage of suitable magnitude and phase in

series with the line. The DVR, with its

excellent capabilities, when installed between

the supply and the sensitive load, can

compensate voltage fluctuations .In this paper

Z-source inverter based DVR is proposed. It

employs a unique X-shaped impedance

network on its DC side for achieving both

voltage buck and boost capabilities This unique

features of ZSI cannot be obtained in the

traditional voltage source and current source

inverters.

Here the control scheme used employed

in Z-source inverter based DVR is fuzzy

controller. The most common choice controller

of the DVR is the PI controller since it has

simple structure and it [25-29]can offer

relatively satisfactory performance over a wide

range of operation. But by using fixed gains,

the controller may not provide the required

control performance, when there are variations

in the system parameters and operating

conditions. It appears that the non linear

controllers are more suitable than the linear

type since the DVR is truly a non linear system.

The proposed fuzzy controller will provide the

desired injecting voltage.

Recent trends in power quality

Some of the issues, which have renewed and

triggered the interest in power quality can be

stated as:[20-24]

Higher demand on supreme power

quality. IT-technology, automated production

plants and commercial activities require a good

and reliable power supply.De-regulating and

commercializing of the of electric energy

markets has made power quality a parameter of

interest to achieve a higher price per kilowatt,

to increase the profit and share of the market.

Decentralization of the production of electricity

with integration of alternative energy sources

and small generation plants have increased

certain power quality problems like surplus of

power, voltage variations and flickers. The

improvements in the power electronics area and

data processing capability have made

improvement in power quality possible by

means of relative cost- effective power

electronic controllers. [30-35]

These trends have triggered interest in different

types of power electronic controllers to

mitigate power quality problems.[36-39]

The main objective of this paper is to improve

the voltage quality in distribution system. The

Z-source inverter based DVR is used to

mitigate the voltage sag/swell and the

compensation is further improved by using

fuzzy controller.

International Journal of Pure and Applied Mathematics Special Issue

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Existing methodology

Voltage Fluctuations, flicker, harmonics



addressed in the distribution system, power

quality problems, a voltage[40-42] Fluctuations

disturbance poses a series threat to the

industries. It can occur more frequently than

any other power quality phenomenon.

Proposed methodology

The main objective of this paper is to improve

the voltage quality in distribution system.

The Z-source inverter based DVR is

used to mitigate the voltage Fluctuations and

the compensation is further improved by using

fuzzy controller. In this paper Z – source

inverter based DVR along with fuzzy controller

is modeled and the same is installed in the

distribution system to provide required load

side compensation. The simulation of the DVR

along with the proposed controller is carried

out using MATLAB/SIMULINK platform.

II Dynamic Voltage Restorer for Voltage

Fluctuations Using Z-source Inverter and

FUZZY Controller

In modern power systems are complex

networks consisting of more number of

generating stations and load centers which are

interconnected through the power transmission

lines. There are many issues involved here such

as maintenance of the power apparatus in the

system and maintaining the stability of the

system operation during fault condition.

The power system especially the

distribution system, have numerous non linear

loads which significantly affect the quality of

power supply. The deviation of voltage, current

or frequency which can be described as a

power quality problems results in collapse or

incorrect operation of customer equipment

.Voltage fluctuations, flicker, harmonics



addressed in the distribution system. Of the

above power quality problems, a voltage

fluctuations disturbance poses a series threat to

the industries. [17-19]It can occur more

frequently than any other power quality

phenomenon. Voltage sag is defined by the

IEEE 1159 as the decrease in the RMS voltage

level to 10%-90% of nominal, at the power

frequency for duration of half to one minute.

Voltage swell is defined by IEEE 1159 as the

increase in the RMS voltage level to 110%-

180% of nominal, at the power frequency for

duration of half cycles to one minute.

Dynamic voltage restorer (DVR) is one

of the power electronic devices connected in

series to the distribution system. It compensates

the voltage disturbances by injecting the

voltage of suitable magnitude and phase in

series with the line. The DVR, with its

excellent capabilities, when installed between

the supply and the sensitive load, can

compensate voltage fluctuations .In this paper


8243

4

Z-source inverter based DVR is proposed. It

employs a unique X-shaped impedance

network on its DC side for achieving both

voltage buck and boost capabilities This unique

features of ZSI cannot be obtained in the

traditional voltage source and current source

inverters.[14-18]

Here the control scheme used employed

in Z-source inverter based DVR is fuzzy

controller. The most common choice controller

of the DVR is the PI controller since it has

simple structure and it can offer relatively

satisfactory performance over a wide range of

operation. But by using fixed gains, the

controller may not provide the required control

performance, when there are variations in the

system parameters and operating conditions. It

appears that the non linear controllers are more

suitable than the linear type since the DVR is

truly a non linear system. The proposed fuzzy

controller will provide the desired injecting

voltage.

The injection transformer is connected

in series with the sensitive load which is to be

protected by the DVR. The basic function of

this transformer is to connect the DVR to the

distribution system and the injected voltages

generated by the inverter are introduced into

the distribution system.

Z-source inverter

Z-Source inverter are the buck- boost

inverters that contain unique passive input

circuits ( impedance networks) and utilize the

shoot-through of the inverter bridge to boost

the DC input voltage.[22-29]

Fuzzy logic controller

The fuzzy logic controller unlike

conventional controllers does not require a

mathematical model of the system process

being controlled. However, an understanding of

the system process and the control

requirements is necessary. [31-35]The fuzzy

controller designs must define what

information data flows into the system (control


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input variable), how the information data is

processed (control strategy and decision) and

what information data flows out of the system

(solution output variables).

In this study, a fuzzy logic based

feedback controller is employed for controlling

the voltage injection of the proposed dynamic

voltage restorer (DVR). Fuzzy logic controller

is preferred over the conventional PI and PID

controller because of its robustness to system

parameter variations during operation and its

simplicity of implementation. The proposed

FLC scheme exploits the simplicity of the

mamdani type fuzzy systems that are used in

the design of the controller and adaptation

mechanism.

The fuzzy logic control scheme can be

divided into four main functional blocks

namely knowledge base, fuzzification,

inference mechanism and defuzzification. The

knowledge base is composed of database and

rule base. Data base consists of input and

output membership functions and provides

information for appropriate fuzzification and

defuzzification operations.[15-17] The rule

base consists of a set of linguistic rules relating

the fuzzified input variables to the desired

control actions. Fuzzification converts a crisp

input voltage signals, error voltage signal (e)

and change in error voltage signal (ce) into

fuzzified signals that can be identified by level

of memberships in the fuzzy sets. The inference

mechanism uses the collection of linguistic

rules to convert the input conditions of

fuzzified outputs to crisp control conditions

using the output membership function, which in

the system acts as the changes in the control

input (u).

The set of fuzzy control linguistic rules

is given in table 1. The inference mechanism in

fuzzy logic controller utilizes these rules to

generate the required output.

Operation principle of a DVR

T

he DVR can be used to compensate for

voltage dip by injecting series voltage and to

restore the load voltage for a sensitive load.

The DVR is still very rarely inserted in

the grid and only relative few devices have


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been inserted around the world. Commercial

projects/products regarding the DVR have been

reported. Most of the described projects include

limited information about potential problems

and a detailed description of the design and

control aspects.

Even though the DVR is commercially

available today, the DVR is not a matured

technology and several areas regarding the

design and control of this type of device are at

the basic research level. The design of a DVR

has been treated with focus on the sizing of the

voltage, power and current rating. DVR

structures have been treated, [12-14]addresses

the design considerations for the line-filter for a

DVR. The control strategies to limit the energy

storage have been treated some control issues

regarding series compensation of unbalanced

supply voltages have been treated.Additionally,

the DVR is a series connected device and one

of the drawbacks with series connected devices

is the difficulties to protect the device during

short circuits and avoid interference with the

existing protection equipment, which have been

treated.

The network employs a unique impedance

circuit to couple the converter main circuit to

that of the power source in order to obtain the

unique features that cannot be achieved using

conventional VSI or CSI. The Z-source inverter

(ZSI) has been reported suitable for residential

PV system because of the capability of voltage

boost and inversion in a single stage.[24-29]

The unique feature about Z- source

inverter is that the output voltage can be

anywhere from zero to infinity. The inverter

can perform both buck and boost operation and

provide a wide range of output voltage which is

not possible in conventional voltage source and

current source inverters. The Z-source inverter

has nine permissible switching states which has

an extra state compared to the conventional

inverters. The extra switching state arises from

the shoot through state of the network in which

two switches of the same leg is switched ON

and conduct simultaneously which is not

possible in conventional inverters.

Design of z source network

To describe the operating principle and

control of the improved Z-source, let us briefly

examine the improved Z-source inverter

structure.

Where

L1 and L2 - series arm inductors

C1 and C2 - parallel arm capacitors

V1 - input voltage

V2 - output voltage


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The network can be redrawn this way as

shown in Below

Redrawn network of improved Z-source

Now assume I2 =0, the current I1enters

the bridge at point 1 and divides equally

between the two arms of the bridge.

Using Kirchoff’s law

( I1 )L/2+V2 = I1/2c

V2 = I1/2c - I1.L/2

V2 = I1/2 [1/c -L]

Assume c = 470*(10^-6)F

440 = 5/2 [1/5.5*10-3- L]

L = 5.8 H

Vdc= B*V0

Vdc = (2B/B+1) Vc.

Where B = 2B/B+1.

The three-phase improved Z-source-

source inverter bridge has nine permissible

switching states unlike the traditional three-

phase V-source inverter that has eight. The

traditional three-phase V-source inverter has

six active vectors when [24-26]the dc voltage is

impressed across the load and two zero vectors

when the load terminals are shorted through

either the lower or upper three devices,

respectively. However, the three-phase

improved Z-source inverter bridge has one

extra zero state.

III Simulation Results of DVR :

DYNAMIC VOLTAGE RESTORER

Voltage sag

Under faulty condition Voltage

is reduced in the period of 0.3 to 0.7


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DVR injecting voltage

The DVR gets activated and injects the

required voltage thereby clearing the fault at

0.3s.

Voltage compensated

The restored voltage after the activation

of DVR

Voltage swell

Under faulty condition voltage will rise

above the rated value

DVR injecting voltage

The DVR gets activated and injects the

required voltage thereby clearing the fault at

0.3s.

Voltage compensated

The restored voltage after the activation

of DVR


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The system Improves the power quality, attains

the transient stability suddenly, Buck and boost

operations can be done, Increases the system

stability, Operation is easy, Compensation is

done at the quick instant when transient occurs,

High efficiency.[40-45]

CONCLUSION

DVR serves as an effective custom power

device for mitigating voltage Fluctuations in

the distribution system. In case of external

disturbances the proposed DVR injects

appropriate voltage component to dynamically

correct any deviation in supply voltage in order

to maintain balanced and constant load voltage

at nominal value. In this paper Z – source

inverter based DVR along with fuzzy controller

is modeled and the same is installed in the

distribution system to provide required load

side compensation. The simulation of the DVR

along with the proposed controller is carried

out using MATLAB/SIMULINK platform. The

Dynamic Voltage Restorer (DVR) is a

promising and effective device for power

quality enhancement due to its quick response

and high reliability. The role of a DVR in

mitigating the power quality problems in terms

of voltage sag, swell is explained. This study

has proposed the modeling and simulation of

DVR using simulink in Mat lab. The very

simple abc to dqo based control technique used.

Simulation result show the DVR mitigates

voltage sags and swells very fast. The

conclusion is that the DVR is an effective

apparatus to protect sensitive loads from short

duration voltage sags and swells. The

simulation results shows that the performance

of Z – source inverter based DVR along with

fuzzy controller is better compared to PI

controller.

REFERENCES

1. Nimal, R.J.G.R., Hussain, J.H., Effect

of deep cryogenic treatment on EN24

steel, International Journal of Pure and

Applied Mathematics, V-116, I-17

Special Issue, PP-113-116, 2017

2. Parameswari, D., Khanaa, V.,

Deploying lamport clocks and linked

lists, International Journal of Pharmacy

and Technology, V-8, I-3, PP-17039-

17044, 2016

3. Parameswari, D., Khanaa, V., Case for

massive multiplayer online role-playing

games, International Journal of

Pharmacy and Technology, V-8, I-3,

PP-17404-17409, 2016

4. Parameswari, D., Khanaa, V.,

Deconstructing model checking with

hueddot, International Journal of


PP-17370-17375, 2016


8249

10

5. Parameswari, D., Khanaa, V., The

effect of self-learning epistemologies on

theory, International Journal of


PP-17314-17320, 2016

6. Pavithra, J., Peter, M.,

GowthamAashirwad, K., A study on

business process in IT and systems

through extranet, International Journal

of Pure and Applied Mathematics, V-

116, I-19 Special Issue, PP-571-576,

2017

7. Pavithra, J., Ramamoorthy, R.,

Satyapira Das, S., A report on

evaluating the effectiveness of working

capital management in googolsoft

technologies, Chennai, International

Journal of Pure and Applied

Mathematics, V-116, I-14 Special Issue,

PP-129-132, 2017

8. Pavithra, J., Thooyamani, K.P., A cram

on consumer behaviour on Mahindra

two wheelers in Chennai, International



PP-55-57, 2017

9. Pavithra, J., Thooyamani, K.P., Dkhar,

K., A study on the air freight customer

satisfaction, International Journal of

Pure and Applied Mathematics, V-116,

I-14 Special Issue, PP-179-184, 2017


K., A study on the working capital

management of TVS credit services

limited, International Journal of Pure

and Applied Mathematics, V-116, I-14



K., A study on the analysis of financial

performance with reference to Jeppiaar

Cements Pvt Ltd, International Journal



2017

12. Peter, M., Dayakar, P., Gupta, C., A

study on employee motivation at

Banalari World Cars Pvt Ltd Shillong,

International Journal of Pure and



13. Peter, M., Kausalya, R., A study on

capital budgeting with reference to

signware technologies, International



PP-71-74, 2017

14. Peter, M., Kausalya, R., Akash, R., A

study on career development with

reference to premheerasurgicals,




15. Peter, M., Kausalya, R., Mohanta, S., A

study on awareness about the cost

reduction and elimination of waste

among employees in life line

multispeciality hospital, International



PP-287-293, 2017

16. Peter, M., Srinivasan, V., Vignesh, A.,

A study on working capital

management at deccan Finance Pvt

Limited Chennai, International Journal



2017

17. Peter, M., Thooyamani, K.P.,

Srinivasan, V., A study on performance

of the commodity market based on

technicalanalysis, International Journal



2017

18. Philomina, S., Karthik, B., Wi-Fi

energy meter implementation using

embedded linux in ARM 9, Middle -

East Journal of Scientific Research, V-

20, I-12, PP-2434-2438, 2014

19. Philomina, S., Subbulakshmi, K.,

Efficient wireless message transfer

system, International Journal of Pure




Ignition system for vechiles on the basis


8250

11

of GSM, International Journal of Pure




Avoidance of fire accident by wireless

sensor network, International Journal of



22. Pothumani, S., Anuradha, C.,

Monitoring android mobiles in an

industry, International Journal of Pure



23. Pothumani, S., Anuradha, C., Decoy

method on various environments - A

survey, International Journal of Pure



24. Pothumani, S., Anuradha, C., Priya, N.,

Study on apple iCloud, International



PP-389-391, 2017

25. Pothumani, S., Hameed Hussain, J., A

novel economic framework for cloud

and grid computing, International



PP-5-8, 2017

26. Pothumani, S., Hameed Hussain, J., A

novel method to manage network

requirements, International Journal of



27. Pradeep, R., Vikram, C.J.,

Naveenchandra, P., Experimental

evaluation and finite element analysis of

composite leaf spring for automotive

vehicle, Middle - East Journal of

Scientific Research, V-12, I-12, PP-

1750-1753, 2012

28. Prakash, S., Jayalakshmi, V., Power

quality improvement using matrix

converter, International Journal of Pure



29. Prakash, S., Jayalakshmi, V., Power

quality analysis & power system

study in high voltage systems,




30. Prakash, S., Sherine, S., Control of

BLDC motor powered electric vehicle

using indirect vector control and sliding

mode observer, International Journal of



31. Prakesh, S., Sherine, S., Forecasting

methodologies of solar resource and PV

power for smart grid energy

management, International Journal of



32. Prasanna, D., Arulselvi, S., Decoupling

smalltalk from rpcs in access points,




33. Prasanna, D., Arulselvi, S., Exploring

gigabit switches and journaling file

systems, International Journal of Pure



34. Prasanna, D., Arulselvi, S.,

Collaborative configurations for

wireless sensor networks systems,




35. Priya, N., Anuradha, C., Kavitha, R.,

Li-Fi science transmission of

knowledge by way of light,




36. Priya, N., Pothumani, S., Kavitha, R.,

Merging of e-commerce and e-market-a

novel approach, International Journal of



37. Raj, R.M., Karthik, B., Effective

demining based on statistical modeling

for detecting thermal infrared,



8251

12



38. Raj, R.M., Karthik, B., Energy sag

mitigation for chopper, International



PP-267-270, 2017

39. Raj, R.M., Karthik, B., Efficient survey

in CDMA system on the basis of error

revealing, International Journal of Pure



40. Rajasulochana, P., Krishnamoorthy, P.,

Ramesh Babu, P., Datta, R., Innovative

business modeling towards sustainable

E-Health applications, International

Journal of Pharmacy and Technology,

V-4, I-4, PP-4898-4904, 2012

41. Rama, A., Nalini, C., Shanthi, E., An

iris based authentication system by eye

localization, International Journal of


PP-23973-23980, 2016

42. Rama, A., Nalini, C., Shanthi, E.,

Effective collaborative target tracking

in wireless sensor networks,

International Journal of Pharmacy and

Technology, V-8, I-4, PP-23981-23986,

2016

43. Ramamoorthy, R., Kanagasabai, V.,

Irshad Khan, S., Budget and budgetary

control, International Journal of Pure



44. Ramamoorthy, R., Kanagasabai, V.,

Jivandan, S., A study on training and

development process at Vantec

Logistics India Pvt Ltd, International



PP-201-207, 2017

45. Pradeep, R., Vikram, C.J.,

Naveenchandran, P., Experimental

evaluation and finite element analysis of

composite leaf spring for automotive

vehicle, Middle - East Journal of

Scientific Research, V-17, I-12, PP-

1760-1763, 2013


8252

8253

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