EE-452 Power System Analysis Mannual 2013

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PRACTICALWORK BOOK For Academic Session 2013

POWER SYSTEM ANALYSIS (EE-452)For

BE (EE)

Name:

Roll Number:

Class:

Batch: Semester/Term:

Department :

Department of Electrical EngineeringNEDUniversity of Enginee ring & Technology



SAFETY RULES

1. Please don’t touch any live parts.

2. Never use an electrical tool in a damp place.3. Don’t carry unnecessary belongings during performance of

practicals (like water bottle, bags etc).4. Before connecting any leads/wires, make sure power is switched off.

5. In case of an emergency, push the nearby red color emergency switch of the panel or immediately call for help.

6. In case of electric fire, never put water on it as it will further worsen thecondition; use the class C fire extinguisher.

Fire is a chemical reaction involving rapid oxidation(combustion) of fuel. Three basic conditions when met,

fire takes place. These are fuel, oxygen & heat, absenceof any one of the component will extinguish the fire.

If there is a small electrical fire, be sure to use

only a Class C or multipurpose (ABC) fireextinguisher, otherwise you might make the

problem worsen.

The letters and symbols are explained in leftfigure. Easy to remember words are also shown.

Don’t play with electricity, Treat electricity with respect, it deserves!

Figure: Fire Triangle

A(think ashes):

paper, wood etc

B(think barrels):

flammable liquids

C(think circuits):

electrical fires



Electrical Power System Analysis Contents

NED University of Engineering and Technology Department of Electrical Engineering

Revised 2012 MMA

CONTENTS

Lab.No.

Dated List of Experiments PageNo.

Remarks

01Studying the operation of a power

transmission line in no-load condition.

02Studying the operation of a power

transmission line in no-load conditions with

increased capacitance.

03

Studying the operation of a power

transmission line in different loadconditions.

Also determining the characteristicimpedance.

04Studying the series operation of power

transmission Lines.

05Studying the parallel operation of power

transmission lines.

06 Bus admittance Matrix

07Solution of Non Linear Algebaric

Equations

08Line Performance of transmission line on

MATLAB

09Modeling of long transmission line on

MATLAB

10Simulation of Compensation Techniques of

Transmission Line on MATLAB

11Load Flow Analysis on MATLAB and etapsoftware



Electrical Power System Analysis Lab Session 01 NED University of Engineering and Technology Department of Electrical Engineering

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LAB SESSION 01

TITTLE:

Studying the operation of a power transmission line in no-load conditions (no-load current of the

transmission line).

APPARTUS: Simulator of electric lines mod. SEL-1/EV Variable three-phase power supply mod. AMT-3/EV, in option three phase line generated

by the generator control board mod. GCB-1/EV, or a fixed three-phase line 3 x 380 V

Three-phase transformer mod. P 14A/EV Set of leads/jumpers for electrical connections

2 electromagnetic voltmeters with range of 250 - 500 Vac

1 electromagnetic ammeter with range of 100 mAac 1 electromagnetic wattmeter with low power factor 1-2 A / 240-480 V The instruments of the generator control boards mod. GCB-1/EV or two digital

instruments for measuring the parameters of electric energy in three-phase systems mod.

AZ-VIP, can be used as alternative.

THEORY:Power transmission lines are designed to transmit large volumes of power between even far points

(hundreds and sometimes thousands of kilometres). Generally power plants are erected where an

energy source is available, then these plants will serve all the users located in urban and industrialareas. The operating voltage is chosen according to the power in order to minimize Jouleeffect

losses (R I2). It can immediately be realized that losses will be reduced when current is reduced,

but, when huge volumes of power have to be sent, energy will exclusively be transmitted withhigh voltages (of some hundreds of kV). All that will lead to consider also the accessories that arestep-up transformers at the origin and the respective step-down transformers at the destination of

the lines.

PREPARING THE EXERCISE Start this exercise considering the transmission LINE 1 with the following constants:

Resistance = 25 Ω; Capacitance = 0.2 µF; Inductance = 0.072 H; Length = 50 km; Turn the breakers at the origin and at the end of the LINE 1, to OFF.

Connect the measuring instruments between the left busway and the terminals at the

beginning of the LINE 1.

Connect the measuring instruments between the end terminals of the LINE 1 and the right busway.

Connect the jumpers with the set of left capacitors, only in the LINE 1, to reproduce the

capacitance between active conductors (called CL). These capacitors can be connectedeither in star or delta configuration. The delta connection will ensure stronger capacitive

currents. Connect the jumpers with the set of right capacitors, only in the LINE 1, to reproduce the

capacitance between the active conductors and the ground (called CE); connect also the




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jumper that grounds the star center of the capacitors. In this case the only star connection

can be carried out because each line conductor generates a capacitance to the ground. Adjust the position of the selector Resistance LINE 1 at the value of 25 Ω. Connect with the variable three-phase power supply.

The reference electric diagram, the connections and configuration of the line are

respectively shown in the figures 4.1.1 and 4.1.2. Read the electric quantities on the measuring instruments and write them down in the

following table.

OBSERVATION

OPERATIONAL MODE

Enable and adjust the voltage of the power supply at 380 V. The warning lights of the left

busway will be on. If no variable three-phase power supply is available, but only a fixedline is used, the voltage can be adjusted at the nearest rated value through the outlets of per

cent variation of the transformer (+/- 5 %). Turn the breaker at the origin of the LINE 1, to ON.

All the parameters of the starting energy can be measured with the digital instrumentavailable at the origin of the line.

Turn the breaker at the end of the LINE 1, to ON. Read the electric quantities on the measuring instruments and write them down in the

following table.

Actual measurements carried out on the LINE 1 with: Resistance = 25Ω; Capacitance =0.2µF;

Inductance = 0.072 H.

Interlinked

voltage

measured at

the originof the line

U1 (V)

Line current

measured atthe origin

of the lineI1 (A)

Active power


of the lineP1 (W)

Interlinked

voltage

measured at

the endof the line

U2 (V)

Reactive

power

measured at


Q1 (VAR)

Compare the reactive power measured on the line to that calculated with the following formulae:

VARV C Q L L 9380*10*2.0*50**2262

1

VARV C Q L L 3220*10*2.0*50**2262

1

QL = reactive power due to the capacitance between two active Conductors

QE = reactive power due to the capacitance between an active conductor and the ground.




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QL and QE resulting from the formulae indicated above are calculated for only one phase. The total

reactive power of the three-phase system will result from the sum of the powers of both the three

line capacitors and the three capacitors to the ground.Total reactive power of the transmission line:

VARQQQ E LTOT

36*3*3

The no-load operation of the transmission line does not show any active power actually, if the

active power lost by the conductance G is not considered, like in this case. If the measurement is

carried out with proper instruments (wattmeter or wattmeters of low power factor and propercurrent-carrying capacity), however some active power can be detected and this is due to the

dielectric losses and to the discharge resistances available in capacitors.

Repeat and record the measurements excluding the set of capacitors CE to the ground.

Actual measurements carried out on the LINE 1 with: Resistance = 25 Ω; Capacitance = 0.2 µF;

Inductance = 0.072 H.

Interlinkedvoltage

measured at


U1 (V)

Line current


of the line

I1 (A)

Active power


of the line

P1 (W)

Interlinkedvoltage

measured at

the endof the line

U2 (V)

Reactive power

measured at


Q1 (VAR)

As it has been explained in the part 2 at the section of electric constants, a model of overhead line

is represented by an equivalent total capacitance considering both the capacitances betweenconductors and between conductors and ground.

In principle only one set of capacitors is sufficient to reproduce the equivalent capacitance of the

line, in the exercises on the lines available in the simulator.




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Reference electric diagram

Power transmission line in no-load condition.




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Connections of the simulator SEL-1/EV

Fig. 4.1.2 – No-load performance of a power transmission line




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LAB SESSION 02

TITTLE:

Studying the operation of a transmission line in no-load conditions with increased capacitance (no-load current of the transmission line).

APPARTUS: Simulator of electric lines mod. SEL-1/EV

Variable three-phase power supply mod. AMT-3/EV, in option three phase line generated

by the generator control board mod. GCB-1/EV, or a fixed three-phase line 3 x 380 V Three-phase transformer mod. P 14A/EV

Set of leads/jumpers for electrical connections 2 electromagnetic voltmeters with range of 250 - 500 Vac

1 electromagnetic ammeter with range of 0,5 - 1 Aac 1 electrodynamic wattmeter with low power factor 1-2 A / 240-480 V

The instruments of the generator control boards mod. GCB-1/EV or two digitalinstruments for measuring the parameters of electric energy in three-phase systems mod.

AZ-VIP, can be used as alternative

Battery of capacitors, for instance that of 3 x 2 µF of the module AZ 191b, with the

respective discharge resistances.

THEORY:The parameter of capacitance is directly proportional to the length of the transmission line; it is

concentrated into an equivalent total capacitance only for an easier study. Actually the

“parameters” of a transmission line (capacitance and resistance in this particular case) aredistributed; crossing the line resistors the capacitive currents will provoke power losses occurring

even when the transmission line is in no-load condition.

PREPARING THE EXERCISE Prearrange the simulator as in the previous exercise (exercise #1) and connect the

capacitors of the module AZ 191a in parallel with CL (becoming CLaux). Caution: when the

auxiliary capacitors are connected, the current transient could burn out the fuses protectingthe transmission line (intervention due to overcurrent). This trouble can be avoided if the

auxiliary capacitors are not connected when the line is powered, but they will be connected

without any applied voltage; then the voltage will be applied in variable and rising way.

The reference electric diagram is still that shown in the fig. 4.1.1 (exercise #1), whereas theconnections and configuration of the line are shown in the fig. 4.2.1.

Read the electric quantities on the measuring instruments and write them down in thefollowing table.




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OBSERVATION Enable and adjust the voltage of the power supply at 380 V. Turn the breaker at the origin of the LINE 1, to ON.

All the parameters of the starting energy can be measured with the digital instrument

available at the origin of the line. Turn the breaker at the end of the LINE 1, to ON.

Read the electric quantities on the measuring instruments and write them down in the

following table.Actual measurements carried out on the LINE 1 with: Resistance = 25Ω; Capacitance =2.2µF;Inductance = 0.072 H.

Interlinked

voltage


of the lineU1 (V)

Line currentmeasured at

the origin

of the lineI1 (A)

Active power measured at

the origin

of the lineP1 (W)

Interlinked

voltagemeasured at

the end

of the lineU2 (V)

Reactive

power measured at

the origin

of the lineQ1 (VAR)

Compare the reactive power measured on the line to that calculated with the following formula:

VARV C Q L L 8.99380*10*2.2*50**2262

1

Therefore the total reactive power will be:

99.8 x 3 = 299.4 VAR

DO IT YOURSELVES:1) Repeat the measurement as indicated in the exercise #1, or write down the data gathered in thisexercise in the first line of the table shown herebelow.

2) Parallel the set of capacitors of 2µF as in the exercise #2, or write down the data gathered in thisexercise in the second line of the table shown herebelow.

3) Then parallel the set of capacitors of 4 µF instead of those of 2 µF, and write down the values

of the measurement in the third line of the table shown herebelow.

Actual measurements carried out on the LINE 1 with: Resistance = 25Ω; Capacitance = variable

0.2 – 2.2 – 4.2 µF; Inductance = 0.072 H

Capacitance

(F)Interlinked

voltage

measured at


U1 (V)

Line current


of the line

I1 (A)

Active power


of the line

P1 (W)

Interlinkedvoltage

measured at

the endof the line

U2 (V)

Reactive power

measured at


Q1 (VAR)




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0.2 µF

2.2 µF

4.2 µF

4) Refer to the fig. 4.2.1 with the auxiliary capacitance CLaux = 2.2 µF, and write down the three

measures resulting from the changement of the point of connection respectively at the origin of the

line, at half length of the line (between resistors and coils) and at the end of the line.

Capacitance

(F)Interlinked

voltage

measured at

the origin

of the line

U1 (V)

Line current


of the line

I1 (A)

Active power


of the line

P1 (W)

Interlinkedvoltage

measured at

the end

of the line

U2 (V)

Reactive power

measured at

the origin

of the line

Q1 (VAR)2.2 µF

origin of line

2.2 µFhalf line

2.2 µFend of line

CONCLUSIONS CONCERNING THE “DO IT YOURSELVES” SECTIONStudying the transmission lines represented with concentrated parameters will lead to consider that

shifting the set of auxiliary capacitors CLaux from the origin of the line to the half-length of the line

and to the end of the line determines what is explained here below:

when the auxiliary capacitors CLaux are connected at the origin of the transmission line, the

capacitive current crossing it will concern only the generator and it does not provoke any

effect on the line resistance inductance; when the auxiliary capacitors CLaux are connected at half length of the transmission line, the

capacitive current crossing it will also affect the resistance where it provokes a power loss

by Joule effect R x I2; when the auxiliary capacitors CLaux are connected at the end of the transmission line, the

capacitive current will cross not only the resistor (as in the previous point), but also the coil

where it provokes a further power loss R x I2 due to the resistive component of the coil (the

coils of the simulator are wound on a ferromagnetic core and consequently they also have aresistive component).

N.B.: the increased capacitance becomes important when the ground fault in power transmissionlines will be analyzed.




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Fig. 2.1 - No-load performance of a power transmission line with increased capacitance




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LAB SESSION 03

TITTLE:

Studying the operation of a transmission line in different load conditions, determining the voltage

drop, calculating the total performance and finding out the characteristic impedance of the line.


Variable three-phase power supply mod. AMT-3/EV, in option threephase line generated

by the generator control board mod. GCB-1/EV, or a fixed three-phase line 3 x 380 V Three-phase transformer mod. P 14A/EV Set of leads/jumpers for electrical connections

2 digital instruments for measuring the parameters of electric energy in three-phase

systems mod. AZ-VIP (the instruments of the generator control boards mod. GCB-1/EV

can be used in option) Variable resistive load mod. RL-2/EV. It is better to connect also the load RL-1/EV to

carry out fractional measurements. Variable inductive load mod. IL-2/EV.

Variable capacitive load mod. CL-2/EV, or 3 modules AZ 191b (batteries of capacitors 3 x

4 µF), in option.

THEORY:The power losses and voltage drops of a transmission line are defined under load when the root-mean-square values of the electric quantities are measured at both the starting and destination

stations. The simulator will refer to lines with symmetrical conductors and balanced load. This

statement enables to imagine the electric diagram shown in the fig. 1.

Fig.1 - Equivalent diagram of a three-phase line with symmetrical conductors and balanced load




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The diagram of the fig. 1 also includes a fictitious neutral conductor, equidistant from the three

active conductors: this gives the possibility of leading the study of the operating characteristics of

the three-phase line to a mere single-phase circuit consisting of only one of the three line wiresand of an ideal return wire without resistance nor inductance. All that is due to the fact that the

neutral wire of a three-phase line with balanced load would not be crossed by any current and

consequently it could not provoke any ohmic nor inductive voltage drop.

PREPARING THE EXERCISE

Start this exercise considering the transmission LINE 2 with the following constants:Resistance = 8.9 Ω; Capacitance = 0.1µF; Inductance = 0.035 H; Length = 25 km;

Section = 50 mm2 - conductor of copper. As regards other parameters, refer to the table 2.1.

If necessary, remove all the jumpers of the LINE 1 not considered. Turn the breakers at the origin and at the end of the LINE 2, to OFF. Connect the measuring instruments between the left busway and the terminals at the

starting of the LINE 2, and between the end terminals of the LINE 2 and the right busway. Connect the jumpers with the set of left capacitors, in the LINE 2, to reproduce the

capacitance between active conductors (called CL). Carry out the delta connectionensuring stronger capacitive currents. Select the value of 0.1 F for CL.

Connect the jumpers with the set of right capacitors, still in the LINE 2, to reproduce the

capacitance between the active conductors and the ground (called CE); connect also the jumper that grounds the star center of the capacitors. In this case the only star connection

can be carried out because each line conductor generates a capacitance to the ground.

Select the value of 0.1 F for CE too.

Adjust the position of the selector Resistance LINE 2 at the value of 8.9 and that ofinductance at the value of 0.036 H.

Connect with the variable three-phase power supply inserting the three phase insulation

transformer. This transformer is used to insulate the line from the user mains to avoid that,

when connected, the current unbalances of the capacitors CE (capacitance to the ground)can provoke the untimely intervention of the differential protections of high sensitiveness.

If the power supply is insulated from the mains, that is it is not grounded, this three-phase

transformer can be omitted. The reference electric diagram, the connections and configuration of the line are

respectively shown in the figures 4.3.2 and 4.3.3.

OBSERVATION:

Please Read this very carefully:

Line 1 Design Parameters:

Modifiable parameter: Section (capacity in A)

Simulated voltage: 120 kV (working U 3x400 Vmax.) Simulated power: P 10 - 15 - 20 MVA

Working current: 1 A

Equivalent resistance: 18 - 25 - 35 Ω Equivalent inductance: 72 mH

Equivalent distributed capacitance: 2 x 0.2 µF

Protection fuses 1A




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Line 2 Design Parameters:

Modifiable parameter: Length (km)

Simulated voltage: 120 kV (working U 3x400 Vmax.)

Simulated power: 20 MVA

Working current: 1 A

Equivalent resistance: 8.9 - 25 - 35 Equivalent inductance: 144 - 72 - 36 mH

Equivalent distributed capacitance: 2 x 0.1 – 0.2 – 0.4 µF

Protection fuses 1A

So before inserting load make sure the line current should not be exceeded greater than 1A.

In pure resistive case, current would exceed 1A so use either MATLAB or etap software to

fill up the table.

OPERATIONAL MODE FOR DETECTING THE PERFORMANCE WITH RESISTIVE

LOAD

Enable and adjust the voltage of the power supply at 380 V. The warning lights of the left busway will be on. If no variable three-phase power supply is available, but only a fixed

line is used, the voltage can be adjusted at the nearest rated value through the outlets of per

cent variation of the transformer (+/- 5 %). Turn the breakers at the origin and at the end of the LINE 2, to ON. Connect the various steps of the resistive load (apply a balanced load using the same step

for the three phases), read the electric quantities on the instruments and write them down in

the table shown herebelow.

Actual measurements carried out on the LINE 2 with:

Resistance = 8.9Ω; Capacitance = 0.1µF; Inductance = 0.036 H

VoltageU1 (V)

CurrentI1 (A)

Power P1 (W)

Power Q1(Var)

VoltageUA (V)

CurrentIA (A)

Power PA (W)

Power QA (Var)

No load

R1(2200Ω )

R2(1100Ω )

R3(735Ω )

R4(550Ω )

R5(440Ω )

R6(365Ω )

R7(315Ω )

R8(270Ω )

R9(240Ω )

R10(220Ω )

R11(200Ω )

R12(185Ω )




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OPERATIONAL MODE FOR DETECTING THE PERFORMANCE WITH INDUCTIVE

LOAD Replace the resistive load with an inductive load, or add this last. Enable and adjust the voltage of the power supply at 380 V. The warning lights of the left

busway will be on. If no variable three-phase power supply is available, but only a fixed

line is used, the voltage can be adjusted at the nearest rated value through the outlets of percent variation of the transformer (+/- 5 %).

Turn the breakers at the origin and at the end of the LINE 2, to ON.

Connect the various steps of the inductive load (apply a balanced load using the same stepfor the three phases), read the electric quantities on the instruments and write them down in

the table shown herebelow.

Actual measurements carried out on the LINE 2 with:Resistance = 8.9Ω; Capacitance = 0.1µF; Inductance = 0.036 H

VoltageU1 (V)

CurrentI1 (A)

Power P1 (W)

Power Q1(Var)

VoltageUA (V)

CurrentIA (A)

Power PA (W)

Power QA (Var)

No loadL1( 2.3 H)

L1( 2.3 H)

L1( 2.3 H)

OPERATIONAL MODE FOR DETECTING THE PERFORMANCE WITH CAPACITIVE

LOAD Replace the resistive load with a capacitive load, or add this last.


busway will be on. If no variable three-phase power supply is available, but only a fixedline is used, the voltage can be adjusted at the nearest rated value through the outlets of per

cent variation of the transformer (+/- 5 %). Turn the breakers at the origin and at the end of the LINE 2, to ON. Connect the various steps of the capacitive load (assemble balanced loads using the same

step for the three phases), read the electric quantities on the instruments and write them

down in the table shown herebelow.



Voltage

U1 (V)

Current

I1 (A)

Power

P1 (W)

Power

Q1(Var)

Voltage

UA (V)

Current

IA (A)

Power

PA (W)

Power

QA (Var)

No loadC1( 4.5µF)

C2( .0µF)

C1( µF)

OPERATIONAL MODE FOR DETECTING THE PERFORMANCE WITH R–L, R–C

LOAD

Assemble a load with the three resistive, inductive and capacitive modules.




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busway will be on. If no variable three-phase power supply is available, but only a fixed

line is used, the voltage can be adjusted at the nearest rated value through the outlets of percent variation of the transformer (+/- 5 %).

Turn the breakers at the origin and at the end of the LINE 2, to ON.

Connect the various steps of the load, starting from R-L and going on with R-C (assemble balanced loads using the same step for the three phases), read the electric quantities on the

instruments and write them down in the table shown here below.



Steps of

balanced

RLC load

Voltage

U1 (V)

Current

I1 (A)

Power

P1(W)

Power

Q1(Var)

Voltage

UA (V)

Current

IA (A)

Power

PA(W)

Power

QA(Var)

No load

R6(≅360Ω)+L1(≅ 2.3H)R6(≅360Ω)+L2(≅1.15H)

R6(≅360Ω)+L3(≅0.77H)

R6(≅360Ω)+C1(≅4,5μF)

R6(≅360Ω)+C1(≅9.0μF)

R6(≅360Ω)+C1(≅13μF)

CALCULATING VOLTAGE DROP, TOTAL POWER LOSS AND PERFORMANCE IN A

POWER TRANSMISSION LINE

OPERATIONAL MODEUsing the values resulting from the measurements for detecting the performance of a transmission

line with R L C loads, calculate: The absolute value of voltage drop; ∆U = U1 - UA

The absolute value of total losses; P = P1 - PA

The total performance of the transmission line. η = PA / P1

Type of

Load

VoltageU1 (V)

VoltageUA (V)

Voltage

Drop

Power P1 (W)

Power PA(W)

Power

Loss

P(W)

Performance

in load

condition

No load

Load 1

Load 2

Load 3

Load 4

Load 5

Load 6

Load 7

Load 8

Load 9




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DO IT YOURSELVES1. Draw one or more graphs to represent the voltage available at the end of the line and the

per cent performance of the line, according to the different conditions of resistive load.

2. Plot also the trend of the voltage available at the end of the line with resistive, inductive

and capacitive load, on the same graph/s (comparing them). The above shown trend will beobserved.

DETERMINING THE CHARACTERISTIC IMPEDANCEDetermine the value of the current supplied by a merely resistive load connected at the end of the

line provoking the elimination of the reactive power at the origin of the line.

THEORETICAL HINTSThis particular operation occurs when the transmission line is connected with a merely resistive

load and the ohmic value is equivalent to the characteristic impedance. This condition of use is

called natural load.

The line current makes that the reactive power in the coils is equivalent to the reactive power in

the capacitors, therefore the transmission line does not need any external reactive power in theoperation. These hypothetical operating conditions represent the optimum case: in fact the losses

of active power are as low as possible because the current is as weak as possible; actually the

currents annul each other by capacitive and inductive effect.

But the case shown above occurs rarely; actually, every time the line current varies, the balance ismissing. If the current is lower than the balance current, the line is still crossed by capacitive

currents. If the current is higher than the balance current, the line is crossed by inductive currents.The rated current-carrying capacity of an overhead transmission line is considerably higher than

that defined as “natural-load current”, and some inductive reactive power can be found in the

operation.




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DO IT YOURSELVESFind the current value being able to balance the inductive reactive power due to the current

crossing the coils, and the capacitive reactive power due to the capacitors of the LINE 2 with anapplied voltage of 220 V instead of 380 V.

_______________________________________________________________________________________________

_______________________________________________________________________________________________

_______________________________________________________________________________________________

_______________________________________________________________________________________________

_______________________________________________________________________________________________

_______________________________________________________________________________________________

_______________________________________________________________________________________________

Reference electric diagram Power transmission line under load.




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Connections on the simulator SEL-1/EV Fig. – Load performance of a power transmission line




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LAB SESSION 04

TITTLE:

Studying the series operation of power transmission lines.




3 electromagnetic voltmeters with range of 250 - 500 Vac 2 electromagnetic ammeters with range of 0.5 - 1 Aac

The digital instruments for measuring the parameters of electric energy in three-phasesystems mod. AZ-VIP, or the instruments of the generator control boards mod. GCB-1/EV

can be used in option Variable resistive load mod. RL-2/EV. It is better to connect also the load RL-1/EV to

carry out fractional measurements.

THEORY:The power losses and voltage drops of a transmission line are defined under load when the root-mean-square values of the electric quantities are measured at both the starting and destinationstations. The simulator will refer to lines with symmetrical conductors and balanced load. This

statement enables to imagine the electric diagram shown in the fig. 4.3.1.


STRICT PRECAUTIONS FOR INSTRUCTORS AND STUDENTS: Before starting Lab

thoroughly read the Detailed Manual of the Equipment, this Laboratory Manual is very

brief, Laboratory Incharge have Detailed Equipment’s Manual.

Consider two lines with equal current-carrying capacity, but different length, for thisexercise, that is the LINE 1 with the constants: Resistance = 18 Ω; Inductance = 0.072 H;

Length = 50 km; Section = 50 mm2 – conductor of copper; and the LINE 2 with the

constants: Resistance = 8.9 Ω; Inductance = 0.036 H; Length = 25 km; Section = 50 mm2 –

conductor of copper. As regards other parameters refer to the table 2.1. Connect only the jumpers at the origin of the LINE 1 and those of the end of the LINE 2. Connect the end terminals of the LINE 1 (terminals immediately at the right of the breaker)

with the starting terminals of the LINE 2 (terminals at the left of the breaker), via some

leads, to carry out the series connection of the two lines.

Turn the origin and end breakers of both the lines to OFF. Do not connect the jumpers with the capacitors supposing that the parameter of

capacitance is negligible.




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Connect the left busway with the three-phase power supply, and the load with the right

busway. Remember that the allowable voltage value ranges from 0 to 400 V and only ifthis value is approximately at half range, the warning lights available on the left busway

will be on.

The reference electric diagram is shown in the fig. 4.4.1, whereas the connections andconfiguration of the line can be seen in the fig. 4.4.2.

OBSERVATION:

OPERATIONAL MODE 1 (WITHOUT CAPACITORS) Enable and adjust the supply voltage of the line at 380 V.

Turn the origin and end breakers of the LINE 1 to ON, in sequence, then turn the origin

and end breakers of the LINE 2 to ON; now the destination busway is energized by somevoltage that will be signaled by the respective warning lights.

Insert some load steps in the resistive load, in sequence. Read the electric quantities on the measuring instruments and write them down in the table,

calculate the voltage drop according to load. Draw the trend of the voltage at the end of the lines 1 and 2 versus the load current, on a

graph.

LoadCondition

Interlinkedvoltage

measured at

the origin ofthe line 1

U11 (V)

Linecurrent

measured at


I11 (A)

Interlinkedvoltage

measured

at the endof the line 1

U12 (V)

Interlinkedvoltage

measured

at the end ofthe

line 2

U22 (V)

Linecurrent

measured

at theorigin of

the line 2

I22 (A)

Voltagedrop at

the end of

lines

ΔU =

U11– U22

12

3

4

5

6

OPERATIONAL MODE 1 (WITH CAPACITORS)

Connect the left jumpers to reproduce the capacitance between the active conductors, then

connect the jumpers with the right capacitors to reproduce the capacitance between active

conductors and the ground, and write the values of the measurement in the third line of thetable shown here below. Enable and adjust the supply voltage of the line at 380 V. Turn the origin and end breakers of the LINE 1 to ON in sequence, then turn the origin

and end breakers of the LINE 2 to ON; now the destination busway is energized by some

voltage that will be signaled by the respective warning lights. Read the electric quantities on the measuring instruments, with the load steps used before,

and write them down in the table, then calculate the voltage drop according to load.




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Draw the trend of the voltage at the end of the lines 1 and 2 versus the load current, on a

graph.

Load

Condition

Interlinked

voltagemeasured at


U11 (V)

Line

currentmeasured at


I11 (A)

Interlinked

voltagemeasured

at the endof the line 1

U12 (V)

Interlinked

voltagemeasured

at the end ofthe

line 2

U22 (V)

Line

currentmeasured

at theorigin of

the line 2

I22 (A)

Voltage

drop atthe end of

lines

ΔU =

U11– U22

1

2

3

4

5

6

DO IT YOURSELVES

The study of the series connection of transmission lines will lead to the following conclusion:1. Becoming longer the line increases its resistance, and consequently it will suffer higher

voltage drops and power losses;

2. The capacitance increases and consequently the value of reactive power absorbed by

the line in no-load condition will increase. N.B.: the increased capacitance will become important when the ground fault in insulated lines is

examined.

Reference electric diagram: Lines in series




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Connections on the simulator SEL-1/EV Fig.2 – Series connection of two power transmission lines




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LAB SESSION 05

TITTLE:

Studying the parallel operation of power transmission lines




2 electromagnetic voltmeters with range of 250 - 500 Vac 2 electromagnetic ammeters with range of 0.5 - 1 Aac

1 electromagnetic ammeter with range of 1 - 2 Aac The digital instruments for measuring the parameters of electric energy in three-phase

systems mod. AZ-VIP, and/or the instruments of the generator control boards mod. GCB-1/EV can be used in option

Variable resistive load mod. RL-2/EV. It is better to connect also the load RL-1/EV to

carry out fractional measurements.

THEORY:The continuity of the service of distribution of electric energy is very often ensured by “systems”also including spare components that can be enabled, when necessary. This is the reason why,

besides the generators and the step-up/step-down transformers, also the main long-distance power

lines have a “spare” line, that is a line in parallel that can be used to meet a demand of energyincrease, but this type of is also very often used as substitute of the normal line to enable

maintenance operations of the power line. Maintenance is generally scheduled and carried out in

certain periods when the demand for power is lower. But this spare line can be enabled not onlyfor routine maintenance, but also for faults in the main line. Under this hypothesis, a long-distance

power line can always be considered as a single line, apart from the few instants when the lines are

in parallel to avoid the interruption of power. This exercise will examine the normal operation oftwo lines in parallel with each other.


STRICT PRECAUTIONS FOR INSTRUCTORS AND STUDENTS: Before starting Lab

thoroughly read the Detailed Manual of the Equipment. This Laboratory Manual is verybrief, Laboratory Incharge have Detailed Equipment’s Manual.

Consider two equal lines, with the following constants: Resistance = 18 Ω; Inductance =

0.072 H; Capacitance = 0.2µF; Length = 50 km; Section = 50 mm2 – conductor of copper.

As regards other parameters refer to the table 2.1. Connect all the jumpers at the origin and at the end of the lines, enable both sets of

capacitors (those of left hand between phases, and those of right end to ground).




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Turn the origin and end breakers of both the lines to OFF. Connect the left busway with the three-phase power supply, and the load with the right

busway.

The reference electric diagram is shown in the fig. 4.4.1, whereas the connections and

configuration of the line can be seen in the fig. 4.4.2.

OPERATIONAL MODE

Enable and adjust the supply voltage of the line at 380 V. Turn the origin and end breakers of both the lines to ON; now the destination busway is

energized by some voltage that will be signaled by the respective warning lights.

Insert a load step ranging from 50% to 60 % of the current-carrying capacity of each line

(rated current of the lines of the simulator = 1 A), in the resistive load. Read the electric quantities on the measuring instruments and write them down in the

table; calculate the voltage drop according to load. Assess how currents are distributed in the two power lines.

Plot the trend of the voltage versus the load current, on a graph. Now disconnect one of the two parallel lines and repeat the measurements. The line still

operating is crossed by overcurrent, but the voltage drop is increased.

OBSERVATION:

Load

Condition

Interlinked

voltagemeasured at

the left

busway U1

(V)

Current of

line 1I1 (A)

Current of

line 2I2 (A)

Load current

IC (A)

Interlinked

voltagemeasured

at the right

busway U2

(V)

Voltage

drop atthe end of

lines

ΔU = U11

– U22

1 (2lines)

2 (2lines)

3 (2lines)

4 (2lines)

5 (2lines)

6 (2lines)

1 (1lines)

2 (1lines)

3 (1lines)

4 (1lines)5 (1lines)

6 (1lines)




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CONCLUSION:

The study of the parallel connection of transmission lines will lead to the following conclusion:

1. The lines normally working in parallel in case of inefficiency of a line, cannot bear the

load for long time; however they can power the user, but with higher voltage drops(being the load equal);

2. The capacitance increases and consequently the value of reactive power absorbed by

the line in no-load condition will increase.

N.B.: the increased capacitance will become important when the ground fault in insulated lines is

examined.

Reference electric diagram

Lines in series




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Connections on the simulator SEL-1/EV

Fig.2 – Series connection of two power transmission lines




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LAB SESSION 06

TITTLE:

Bus Admittance Matrix on MATLAB

TASK:1. Simulate the two systems on etap software.2. For the given power system, find the bus admittance matrix using Y=ybus1(zdata).

Instruction:

To use the above command power tool box should be installed(Reference Book Hadi Saadat)

Fig 1

Fig 2




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Also solve for the bus voltages.

For fig 2. Assume E1= 1.1 pu and E2=1.0pu.

Write down the MATLAB code here.

And calculate the Ybus and bus voltages mathematically.

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LAB SESSION 07

TITTLE:

To solve the Non Linear Algebraic Equations

TASK:1. Use the Gauss-Seidel Method to find a root of the following equations using MATLAB up

to 6 iterations.

0496)( 23 x x x x f

Also plot the curve

x x g )(For the values between 0 to 4.5 to find the intersection point, roots of f(x).


Also mathematically calculate the roots for two iterations.

2. Use the Newton Raphson Method to find a root of the following equations using

MATLAB up to 6 iterations. Assume an initial estimate of 60 x

0496)(

23 x x x x f

Also plot the curve

)( x f vs

For the values between 0 to 6 to find the intersection point, roots of f(x).


Also mathematically calculate the roots for two iterations.

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LAB SESSION 08

TITTLE:

Line Performance of transmission line on MATLAB

TASK:A three phase 50Hz, 220kV transmission line having length of 600km. The line parameters per phase per unit length are found to be

r=0.016 Ω/km ; L= 0.97mH/km ; C=0.0115µF/km

a. Determine the line performance when load at the receiving end is 800 MW 0.8 power

factor lagging 200kV.

b. Determine the receiving end quantities and the line performance when 600MW and

400MVAr are being transmitted at 210kV from the sending end.c. Determine the sending end quantities and the line performance when the receiving end

load impedance is 290Ω at 500kV.d. Find the receiving end quantities when the line is terminated in an open circuit and is

energized with 500kV at the sending end. Also determine the reactance and the MVAR

of three phase shunt reactor to be installed at the receiving end in order to limit the

receiving end voltage to 500kV.e. Draw the voltage profile for both compensated and uncompensated line.

f. Find the receiving end and the sending end currents when the line is terminated at the

short circuit.g. Construct the receiving end circle.

h. Determine the line voltage profile for the following cases.

a. No load b. Rated load

c. Line terminated in the SIL

d. Short Circuited Linei. Obtain the line load ability curve.

Instruction:

To solve the above problem power tool box should be installed.(Reference Book Power System Analysis By Hadi Saadat)




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Solve the above task on MATLAB and attached the results.

And calculate the above mathematically here (insert extra sheets if required).

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LAB SESSION 09

TITTLE:

Voltage Profile and Modeling of a Long Transmission Line on MATLAB

TASK:

1. Model the Long Transmission Line on MATLAB software (assume necessary data)

and attached your simulations with experiment.

a) With Load

b) Without Load

Vs=132kV * sqrt(2) (Vmax) No. of phases=1 Vm=125kV

f= 60Hz f=60Hz f=60Hz

R=0.996 ohm/km P=50MW

L=1.36 mH/km QL=0

C=0.85 exp(-8) Qc=0

Length = 370km

And observe the following:

1. Increase in Load current will increase the voltage drop and thus poorer the voltage

regulation.

2. At no load Voltage Regulation will be negative (Vr > Vs) i.e Feranti Effect.

3. Effect of Load Power Factor on Voltage regulation.

4. Observe the phenomenon of Surge Impedance Load.

5. Difference between SIL and Characteristics Impedance.

And note down your observation:

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2. A 50 Hz, Transmission line 300 km long has a total series impedance of 40+j1.25 Ω. and a

total shunt admittance of 10 exp (-3) mho. The receiving end load is 50 MW at 220 kV with

0.8 lagging power factor. Find the sending end voltage, current, power & power factor

using:

a) Nominal T Method.

b) Nominal Π method.

3. A 3 phase, 50 Hz transmission line is 400 km long. The voltage at the sending end is 220

kV. The line parameters are r = 0.1250 Ω /km, x = 0.4 Ω/km and g = 2.8*10 exp(-6)

mho/km. Now if the line is open circuited with a receiving end voltage of 220 kV, find the

r.m.s. value and phase angle of following:

a) The incident and reflected waves of voltages to neutral at the receiving end.

b) The incident and reflected voltages to neutral at 200 km from receiving end.




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LAB SESSION 10

TITTLE:

Simulation of Compensation Techniques of Transmission Line on MATLAB

THEORY:

Model the Long Transmission Line With

(1) Series Compensation

(2) Shunt Compensation

on MATLAB software.

c) With No Compensation

d) With 50% compensation

e) With 75% compensation

f) With 90% compensation

Assume any transmission line with suitable parameters.

And note down your observation:

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LAB SESSION 11

TITTLE:

Load Flow Analysis on MATLAB and etap software.

TASK:

1. Simulate the two systems on etap software (the necessary data you can assume).

Fig 1

Fig 2

The above two examples are from the Book of Power System Analysis By Hadi Saadat.

1. Write down the MATLAB code for load flow analysis using Gauss Seidal Method.

Instruction:

To use the power commands power tool box should be installed(Reference Book Power System Analysis By Hadi Saadat)

2. Mathematically calculate the load flow solution for the above cases.




MATLAB CODE:

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EE-452 Power System Analysis Mannual 2013

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