EE-452 -- Power System Analysis_ 2011

8/6/2019 EE-452 -- Power System Analysis_ 2011

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PRACTICAL WORK BOOKFor Academic Session 2011

POWER SYSTEM ANALYSIS (EE-452)For

BE (EE)

Name:Roll Number:Class:Batch: Semester/Term :

Department :

Department of Electrical EngineeringNED University of Engineering & Technology, Karachi


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SAFETY RULES

1. Please dont touch any live parts.2. Never use an electrical tool in a damp place.3. Dont 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 the

condition; 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 useonly 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.

Dont 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


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Electrical Power System Protection Contents NED University of Engineering and Technology Department of Electrical Engineering

Revised 2011 MMA

CONTENTS

Lab.No. Da ted List of Experiments PageNo . Remarks

01 Studying the operation of a power transmission line in no-load condition.

02Studying the operation of a power transmission line in no-load conditions withincreased capacitance.

03

Studying the operation of a power transmission line in different loadconditions.Also determining the characteristicimpedance.

04 Studying the series operation of power transmission Lines.

05 Studying the parallel operation of power transmission lines.06 Bus admittance Matrix

07 Solution of Non Linear AlgebaricEquations

08 Line Performance of transmission line on

MATLAB09 Modeling of long transmission line onMATLAB

10 Simulation of Compensation Techniques of Transmission Line on MATLAB

11 Load Flow Analysis on MATLAB and etapsoftware


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Electrical Power System Protection 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 thetransmission line).

APPARTUS:Simulator of electric lines mod. SEL-1/EVVariable 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 VThree-phase transformer mod. P 14A/EVSet of leads/jumpers for electrical connections2 electromagnetic voltmeters with range of 250 - 500 Vac1 electromagnetic ammeter with range of 100 mAac1 electromagnetic wattmeter with low power factor 1-2 A / 240-480 VThe 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.

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 anenergy 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 Jouleeffectlosses (R I 2). 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 EXERCISEStart this exercise considering the transmission LINE 1 with the following constants:Resistance = 25 ; Capacitance = 0.2 F; 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 thecapacitance between active conductors (called C L). These capacitors can be connectedeither in star or delta configuration. The delta connection will ensure stronger capacitivecurrents.Connect the jumpers with the set of right capacitors, only in the LINE 1, to reproduce thecapacitance between the active conductors and the ground (called C E); connect also the


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jumper that grounds the star center of the capacitors. In this case the only star connectioncan 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 .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 thefollowing table.

OBSERVATIONOPERATIONAL 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 thefollowing table.

Actual measurements carried out on the LINE 1 with: Resistance = 25 ; Capacitance =0.2F;Inductance = 0.072 H.

Interlinkedvoltage

measured at

the originof the lineU1 (V)

Line currentmeasured at

the originof the line

I1 (A)

Active power measured at


P1 (W)

Interlinkedvoltage

measured at

the endof the lineU2 (V)

Reactive power

measured at

the originof the lineQ1 (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 ConductorsQE = reactive power due to the capacitance between an active conductor and the ground.


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QL and Q E resulting from the formulae indicated above are calculated for only one phase. The totalreactive power of the three-phase system will result from the sum of the powers of both the threeline 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 theactive power lost by the conductance G is not considered, like in this case. If the measurement iscarried out with proper instruments (wattmeter or wattmeters of low power factor and proper current-carrying capacity), however some active power can be detected and this is due to thedielectric losses and to the discharge resistances available in capacitors.

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

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

Inductance = 0.072 H.Interlinked

voltagemeasured at


U1 (V)



I1 (A)



P1 (W)

Interlinkedvoltage

measured atthe end

of the lineU2 (V)

Reactive power

measured atthe originof the lineQ1 (VAR)

As it has been explained in the part 2 at the section of electric constants, a model of overhead lineis 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 theline, 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).


by the generator control board mod. GCB-1/EV, or a fixed three-phase line 3 x 380 VThree-phase transformer mod. P 14A/EVSet of leads/jumpers for electrical connections2 electromagnetic voltmeters with range of 250 - 500 Vac

1 electromagnetic ammeter with range of 0,5 - 1 Aac1 electrodynamic wattmeter with low power factor 1-2 A / 240-480 VThe 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 alternativeBattery of capacitors, for instance that of 3 x 2 F of the module AZ 191b, with therespective discharge resistances.

THEORY:The parameter of capacitance is directly proportional to the length of the transmission line; it isconcentrated 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 occurringeven when the transmission line is in no-load condition.

PREPARING THE EXERCISEPrearrange the simulator as in the previous exercise (exercise #1) and connect thecapacitors of the module AZ 191a in parallel with C L (becoming C Laux ). Caution: when theauxiliary capacitors are connected, the current transient could burn out the fuses protectingthe transmission line (intervention due to overcurrent). This trouble can be avoided if theauxiliary capacitors are not connected when the line is powered, but they will be connectedwithout 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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OBSERVATIONEnable 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 thefollowing table.

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

Interlinkedvoltage

measured atthe origin

of the lineU1 (V)



I1 (A)



P1 (W)

Interlinkedvoltage

measured atthe end

of the lineU2 (V)

Reactive power

measured atthe 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 2F 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 F instead of those of 2 F, and write down the valuesof the measurement in the third line of the table shown herebelow.

Actual measurements carried out on the LINE 1 with: Resistance = 25 ; Capacitance = variable0.2 2.2 4.2 F; Inductance = 0.072 H

Capacitance( F)

Interlinkedvoltage

measured atthe originof the line

U1 (V)



I1 (A)



P1 (W)

Interlinkedvoltage

measured atthe end

of the lineU2 (V)

Reactive power



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0.2 F

2.2 F

4.2 F

4) Refer to the fig. 4.2.1 with the auxiliary capacitance C Laux = 2.2 F, and write down the threemeasures resulting from the changement of the point of connection respectively at the origin of theline, at half length of the line (between resistors and coils) and at the end of the line.

Capacitance( F)

Interlinkedvoltage

measured atthe originof the line

U1 (V)



I1 (A)



P1 (W)

Interlinkedvoltage

measured atthe end

of the lineU2 (V)

Reactive power


2.2 Forigin of line

2.2 Fhalf line2.2 F

end of line

CONCLUSIONS CONCERNING THE DO IT YOURSELVES SECTIONStudying the transmission lines represented with concentrated parameters will lead to consider thatshifting the set of auxiliary capacitors C Laux 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 C Laux are connected at the origin of the transmission line, thecapacitive current crossing it will concern only the generator and it does not provoke anyeffect on the line resistance inductance;when the auxiliary capacitors C Laux are connected at half length of the transmission line, thecapacitive current crossing it will also affect the resistance where it provokes a power loss

by Joule effect R x I 2;when the auxiliary capacitors C Laux are connected at the end of the transmission line, thecapacitive current will cross not only the resistor (as in the previous point), but also the coilwhere it provokes a further power loss R x I 2 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 voltagedrop, calculating the total performance and finding out the characteristic impedance of the line.

APPARTUS:Simulator of electric lines mod. SEL-1/EVVariable 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 VThree-phase transformer mod. P 14A/EVSet of leads/jumpers for electrical connections2 digital instruments for measuring the parameters of electric energy in three-phasesystems 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 tocarry 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 x4 F), 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 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. 1.

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


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Line 2 Design Parameters:Modifiable parameter: Length (km)Simulated voltage: 120 kV (working U 3x400 Vmax.)Simulated power: 20 MVAWorking current: 1 AEquivalent resistance: 8.9 - 25 - 35Equivalent inductance: 144 - 72 - 36 mHEquivalent distributed capacitance: 2 x 0.1 0.2 0.4 FProtection 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 tofill up the table.

OPERATIONAL MODE FOR DETECTING THE PERFORMANCE WITH RESISTIVELOAD

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 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 stepfor the three phases), read the electric quantities on the instruments and write them down inthe table shown herebelow.

Actual measurements carried out on the LINE 2 with:Resistance = 8.9 ; Capacitance = 0.1F; 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 loadR1 ( 2200 )R2 ( 1100 )R3 ( 735 )R4 ( 550 )R5 ( 440 )R6 ( 365 )R7 ( 315 )R8 ( 270 )R9 ( 240 )R10 ( 220 )R11 ( 200 )R12 ( 185 )


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OPERATIONAL MODE FOR DETECTING THE PERFORMANCE WITH INDUCTIVELOAD

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 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 inductive load (apply a balanced load using the same stepfor the three phases), read the electric quantities on the instruments and write them down inthe table shown herebelow.

Actual measurements carried out on the LINE 2 with:Resistance = 8.9 ; Capacitance = 0.1F; Indu ctance = 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 CAPACITIVELOAD

Replace the resistive load with a capacitive 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 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 samestep for the three phases), read the electric quantities on the instruments and write themdown in the table shown herebelow.


VoltageU1 (V)

CurrentI1 (A)

Power P1 (W)

Power Q1(Var)

VoltageUA (V)

CurrentIA (A)

Power PA (W)

Power QA (Var)

No loadC1 ( 4.5F)C2 ( .0F)C1 ( F)

OPERATIONAL MODE FOR DETECTING THE PERFORMANCE WITH RL, RCLOAD

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


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


Steps of balancedRLC load

VoltageU1 (V)

CurrentI1 (A)

Power P1(W)

Power Q1(Var)

VoltageUA (V)

CurrentIA (A)

Power PA(W)

Power QA(Var)

No load

R6( 360 )+L1( 2.3H)R6( 360 )+ L2( 1.15H)R6( 360)+ L3( 0.77H)R6( 360)+C1( 4,5F)R6( 360)+C1( 9.0 F)R6( 360)+C1( 13 F)

CALCULATING VOLTAGE DROP, TOTAL POWER LOSS AND PERFORMANCE IN APOWER TRANSMISSION LINEOPERATIONAL MODEUsing the values resulting from the measurements for detecting the performance of a transmissionline with R L C loads, calculate:

The absolute value of voltage drop; U = U1 - UAThe absolute value of total losses; P = P1 - PAThe total performance of the transmission line. = PA / P1

Type of Load

VoltageU1 (V)

VoltageUA (V)

VoltageDrop

Power P1 (W)

Power PA(W)

PowerLossP(W)

Performancein loadcondition

No loadLoad 1Load 2Load 3Load 4Load 5Load 6Load 7Load 8Load 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 theline 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 resistiveload and the ohmic value is equivalent to the characteristic impedance. This condition of use iscalled natural load.

The line current makes that the reactive power in the coils is equivalent to the reactive power inthe 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 lossesof active power are as low as possible because the current is as weak as possible; actually thecurrents 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 capacitivecurrents. 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 thanthat defined as natural-load current, and some inductive reactive power can be found in theoperation.


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


by the generator control board mod. GCB-1/EV, or a fixed three-phase line 3 x 380 VThree-phase transformer mod. P 14A/EVSet of leads/jumpers for electrical connections3 electromagnetic voltmeters with range of 250 - 500 Vac2 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/EVcan be used in optionVariable resistive load mod. RL-2/EV. It is better to connect also the load RL-1/EV tocarry 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. Thisstatement enables to imagine the electric diagram shown in the fig. 4.3.1.

PREPARING THE EXERCISE

STRICT PRECAUTIONS FOR INSTRUCTORS AND STUDENTS: Before starting Labthoroughly read the Detailed Manual of the Equipment, this Laboratory Manual is verybrief, Laboratory Incharge have Detailed Equipments Manual.

Consider two lines with equal current-carrying capacity, but different length, for thisexercise, that is the LINE 1 with the constants: Resistance = 18 ; Inductance = 0.072 H;Length = 50 km; Section = 50 mm 2 conductor of copper; and the LINE 2 with theconstants: Resistance = 8.9 ; Inductance = 0.036 H; Length = 25 km; Section = 50 mm 2

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 someleads, 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 if this value is approximately at half range, the warning lights available on the left buswaywill 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 originand 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 agraph.

LoadCondition

Interlinkedvoltagemeasured atthe origin of the line 1

U11 (V)

Linecurrentmeasured atthe origin of the line 1

I11 (A)

Interlinkedvoltagemeasuredat the endof the line 1

U12 (V)

Interlinkedvoltagemeasuredat the end of theline 2U22 (V)

Linecurrentmeasuredat theorigin of the line 2I22 (A)

Voltagedrop atthe end of lines

U =U11 U22

123456

OPERATIONAL MODE 1 (WITH CAPACITORS)

Connect the left jumpers to reproduce the capacitance between the active conductors, thenconnect 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 somevoltage 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 agraph.

Load

Condition

Interlinked

voltagemeasured atthe origin of the line 1

U11 (V)

Line

currentmeasured atthe origin of the line 1

I11 (A)

Interlinked

voltagemeasuredat the endof the line 1

U12 (V)

Interlinked

voltagemeasuredat the end of theline 2U22 (V)

Line

currentmeasuredat theorigin of the line 2I22 (A)

Voltage

drop atthe end of lines

U =U11 U22

123456

DO IT YOURSELVESThe 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 bythe line in no-load condition will increase.

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

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


by the generator control board mod. GCB-1/EV, or a fixed three-phase line 3 x 380 VThree-phase transformer mod. P 14A/EVSet of leads/jumpers for electrical connections2 electromagnetic voltmeters with range of 250 - 500 Vac2 electromagnetic ammeters with range of 0.5 - 1 Aac

1 electromagnetic ammeter with range of 1 - 2 AacThe digital instruments for measuring the parameters of electric energy in three-phasesystems mod. AZ-VIP, and/or the instruments of the generator control boards mod. GCB-1/EV can be used in optionVariable resistive load mod. RL-2/EV. It is better to connect also the load RL-1/EV tocarry out fractional measurements.

THEORY:The continuity of the service of distribution of electric energy is very often ensured by systemsalso 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 enablemaintenance operations of the power line. Maintenance is generally scheduled and carried out incertain 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 arein parallel to avoid the interruption of power. This exercise will examine the normal operation of two lines in parallel with each other.

PREPARING THE EXERCISESTRICT 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 Equipments Manual.

Consider two equal lines, with the following constants: Resistance = 18 ; Inductance =0.072 H; Capacitance = 0.2F; Length = 50 km; Section = 50 mm 2 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 MODEEnable 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 isenergized 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 thetable; 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 stilloperating is crossed by overcurrent, but the voltage drop is increased.

OBSERVATION:

LoadCondition

Interlinkedvoltagemeasured atthe left

busway U1

(V)

Current of line 1I1 (A)

Current of line 2I2 (A)

Load currentIC (A)

Interlinkedvoltagemeasuredat the right

busway U2

(V)

Voltagedrop atthe end of linesU = 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 bythe line in no-load condition will increase.

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

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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Electrical Power System Analysis Lab Session 06 NED University of Engineering and Technology Department of Electrical Engineering

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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).

Write down the MATLAB code here.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 vsFor the values between 0 to 6 to find the intersection point, roots of f(x).

Write down the MATLAB code here.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 /km ; L= 0.97mH/km ; C=0.0115F/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 endload impedance is 290 at 500kV.

d. Find the receiving end quantities when the line is terminated in an open circuit and isenergized 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 thereceiving 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 loadc. Line terminated in the SILd. Short Circuited Line

i. 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 Loadb) Without Load

Vs=132kV * sqrt(2) (Vmax) No. of phases=1 Vm=125kVf= 60Hz f=60Hz f=60Hz

R=0.996 ohm/km P=50MWL=1.36 mH/km QL=0C=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.

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2. A 50 Hz, Transmission line 300 km long has a total series impedance of 40+j1.25 . and atotal shunt admittance of 10 exp (-3) mho. The receiving end load is 50 MW at 220 kV with0.8 lagging power factor. Find the sending end voltage, current, power & power factorusing:a) Nominal T Method.b) Nominal method.

3. A 3 phase, 50 Hz transmission line is 400 km long. The voltage at the sending end is 220kV. The line parameters are r = 0.1250 /km, x = 0.4 /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 ther.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 Compensationd) With 50% compensatione) With 75% compensation

f) With 90% compensation

Assume any transmission line with suitable parameters.

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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.


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MATLAB CODE:

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EE-452 -- Power System Analysis_ 2011

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