PRACTICAL WORK BOOK
For Academic Session 2013
POWER SYSTEM ANALYSIS (EE-452)
For
BE (EE)
Name:
Roll Number:
Class:
Batch:
Department :
Semester/Term:
Department of Electrical Engineering
NED University 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 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, absence
of any one of the component will extinguish the fire.
Figure: Fire Triangle
A(think
ashes):
paper, wood etc
B(think
If there is a small electrical fire, be sure to use
only a Class C or multipurpose (ABC) fire
extinguisher, otherwise you might make the
problem worsen.
C(think
The letters and symbols are explained in left
figure. Easy to remember words are also shown.
barrels):
flammable liquids
circuits):
electrical fires
Don’t play with electricity, Treat electricity with respect, it deserves!
Contents
Electrical Power System Analysis
NED University of Engineering and Technology
Department of Electrical Engineering
CONTENTS
Lab.
No.
01
02
03
04
05
06
07
08
09
10
11
Dated
List of Experiments
Page
No.
R e ma r k s
Studying the operation of a power
transmission line in no-load condition.
Studying the operation of a power
transmission line in no-load conditions with
increased capacitance.
Studying the operation of a power
transmission line in different load
conditions.
Also determining the characteristic
impedance.
Studying the series operation of power
transmission Lines.
Studying the parallel operation of power
transmission lines.
Bus admittance Matrix
Solution of Non Linear Algebaric
Equations
Line Performance of transmission line on
MATLAB
Modeling of long transmission line on
MATLAB
Simulation of Compensation Techniques of
Transmission Line on MATLAB
Load Flow Analysis on MATLAB and etap
software
Revised 2012 MMA
Lab Session 01
Electrical Power System Analysis
NED University of Engineering and Technology
Department of Electrical Engineering
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 industrial
areas. 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 with
high voltages (of some hundreds of kV). All that will lead to consider also the accessories that are
step-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 connected
either 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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Lab Session 01
Electrical Power System Analysis
NED University of Engineering and Technology




Department of Electrical Engineering
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 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 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 =0.2µF;
Inductance = 0.072 H.
Interlinked
voltage
measured at
the origin
of the line
U1 (V)
Line current
measured at
the origin
of the line
I1 (A)
Active power
measured at
the origin
of the line
P1 (W)
Interlinked
voltage
measured at
the end
of the line
U2 (V)
Reactive
power
measured at
the origin
of the line
Q1 (VAR)
Compare the reactive power measured on the line to that calculated with the following formulae:
QL  CLV12  2 *  * 50 * 0.2 * 106 * 3802  9VAR
QL  CLV12  2 *  * 50 * 0.2 * 106 * 2202  3VAR
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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Lab Session 01
Electrical Power System Analysis
NED University of Engineering and Technology
Department of Electrical Engineering
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:
QTOT  3 * QL  3 * QE  36VAR
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 proper
current-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.
Interlinked
voltage
measured at
the origin
of the line
U1 (V)
Line current
measured at
the origin
of the line
I1 (A)
Active power
measured at
the origin
of the line
P1 (W)
Interlinked
voltage
measured at
the end
of the line
U2 (V)
Reactive
power
measured at
the origin
of the line
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 between
conductors 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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Electrical Power System Analysis
NED University of Engineering and Technology
Lab Session 01
Department of Electrical Engineering
Reference electric diagram
Power transmission line in no-load condition.
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Electrical Power System Analysis
NED University of Engineering and Technology
Lab Session 01
Department of Electrical Engineering
Connections of the simulator SEL-1/EV
Fig. 4.1.2 – No-load performance of a power transmission line
-4b-|Page
Lab Session 02
Electrical Power System Analysis
NED University of Engineering and Technology
Department of Electrical Engineering
LAB SESSION 02
TITTLE:
Studying the operation of a transmission line in no-load conditions with increased capacitance (noload 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 digital
instruments 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) are
distributed; 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 protecting
the 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 the
connections 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 the
following table.
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Lab Session 02
Electrical Power System Analysis
NED University of Engineering and Technology
Department of Electrical Engineering
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
measured at
the origin
of the line
U1 (V)
Line current
measured at
the origin
of the line
I1 (A)
Active power
measured at
the origin
of the line
P1 (W)
Interlinked
voltage
measured at
the end
of the line
U2 (V)
Reactive
power
measured at
the origin
of the line
Q1 (VAR)
Compare the reactive power measured on the line to that calculated with the following formula:
QL  C LV12  2 *  * 50 * 2.2 *10 6 * 380 2  99.8VAR
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 this
exercise 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 this
exercise 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
the origin
of the line
U1 (V)
Line current
measured at
the origin
of the line
I1 (A)
Active power
measured at
the origin
of the line
P1 (W)
Interlinked
voltage
measured at
the end
of the line
U2 (V)
Reactive
power
measured at
the origin
of the line
Q1 (VAR)
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Lab Session 02
Electrical Power System Analysis
NED University of Engineering and Technology
Department of Electrical Engineering
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
measured at
the origin
of the line
I1 (A)
Active power
measured at
the origin
of the line
P1 (W)
Interlinked
voltage
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 µF
half line
2.2 µF
end of line
CONCLUSIONS CONCERNING THE “DO IT YOURSELVES” SECTION
Studying 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 a
resistive component).
N.B.: the increased capacitance becomes important when the ground fault in power transmission
lines will be analyzed.
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Electrical Power System Analysis
NED University of Engineering and Technology
Lab Session 02
Department of Electrical Engineering
Fig. 2.1 - No-load performance of a power transmission line with increased capacitance
-8-|Page
Lab Session 03
Electrical Power System Analysis
NED University of Engineering and Technology
Department of Electrical Engineering
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.
APPARTUS:








Simulator of electric lines mod. SEL-1/EV
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 rootmean-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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Electrical Power System Analysis
NED University of Engineering and Technology
Lab Session 03
Department of Electrical Engineering
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 wires
and 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 connection
ensuring 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 of
inductance 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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Lab Session 03
Electrical Power System Analysis
NED University of Engineering and Technology
Department of Electrical Engineering
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
Voltage Current
U1 (V) I1 (A)
Power
P1 (W)
Power
Q1(Var)
Voltage
UA (V)
Current
IA (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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Lab Session 03
Electrical Power System Analysis
NED University of Engineering and Technology
Department of Electrical Engineering
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 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 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
Voltage Current Power
Power
Voltage
U1 (V) I1 (A)
P1 (W)
Q1(Var) UA (V)
No load
L1(2.3 H)
L1(2.3 H)
L1(2.3 H)
Current
IA (A)
Power
PA (W)
Power
QA (Var)
OPERATIONAL MODE FOR DETECTING THE PERFORMANCE WITH CAPACITIVE
LOAD
 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 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 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.
Actual measurements carried out on the LINE 2 with:
Resistance = 8.9Ω; Capacitance = 0.1µF; Inductance = 0.036 H
Voltage Current
U1 (V) I1 (A)
Power
P1 (W)
Power
Q1(Var)
Voltage
UA (V)
Current
IA (A)
Power
PA (W)
Power
QA (Var)
No load
C1(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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Lab Session 03
Electrical Power System Analysis
NED University of Engineering and Technology



Department of Electrical Engineering
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 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.
Actual measurements carried out on the LINE 2 with:
Resistance = 8.9Ω; Capacitance = 0.1µF; Inductance = 0.036 H
Voltage Current Power Power
Steps of
Voltage Current Power Power
balanced
U1 (V) I1 (A) P1(W) Q1(Var) UA (V) IA (A) PA(W) QA(Var)
RLC load
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 MODE
Using 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
Voltage Voltage Voltage Power
P1 (W)
U1 (V) UA (V) Drop
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
- 13 - | P a g e
Electrical Power System Analysis
NED University of Engineering and Technology
Lab Session 03
Department of Electrical Engineering
DO IT YOURSELVES
1. 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 be
observed.
DETERMINING THE CHARACTERISTIC IMPEDANCE
Determine 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 HINTS
This 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 the
operation. 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 is
missing. 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.
- 14 - | P a g e
Electrical Power System Analysis
NED University of Engineering and Technology
Lab Session 03
Department of Electrical Engineering
DO IT YOURSELVES
Find 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 an
applied voltage of 220 V instead of 380 V.
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Reference electric diagram
Power transmission line under load.
- 15 - | P a g e
Electrical Power System Analysis
NED University of Engineering and Technology
Lab Session 03
Department of Electrical Engineering
Connections on the simulator SEL-1/EV
Fig. – Load performance of a power transmission line
- 16 - | P a g e
Lab Session 04
Electrical Power System Analysis
NED University of Engineering and Technology
Department of Electrical Engineering
LAB SESSION 04
TITTLE:
Studying the series operation of power transmission lines.
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
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-phase
systems 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 rootmean-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. 4.3.1.
PREPARING THE EXERCISE
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 this
exercise, 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.
- 17 - | P a g e
Lab Session 04
Electrical Power System Analysis
NED University of Engineering and Technology


Department of Electrical Engineering
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 busway
will be on.
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.
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 some
voltage 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.
Load
Interlinked
Condition voltage
measured at
the origin of
the line 1
U11 (V)
Line
current
measured at
the origin of
the line 1
I11 (A)
Interlinked
voltage
measured
at the end
of the line 1
U12 (V)
Interlinked
voltage
measured
at the end of
the
line 2
U22 (V)
Line
current
measured
at the
origin of
the line 2
I22 (A)
Voltage
drop at
the end of
lines
ΔU =
U11– U22
1
2
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 the
table 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.
- 18 - | P a g e
Lab Session 04
Electrical Power System Analysis
NED University of Engineering and Technology

Department of Electrical Engineering
Draw the trend of the voltage at the end of the lines 1 and 2 versus the load current, on a
graph.
Load
Interlinked
Condition voltage
measured at
the origin of
the line 1
U11 (V)
Line
current
measured at
the origin of
the line 1
I11 (A)
Interlinked
voltage
measured
at the end
of the line 1
U12 (V)
Interlinked
voltage
measured
at the end of
the
line 2
U22 (V)
Line
current
measured
at the
origin of
the line 2
I22 (A)
Voltage
drop at
the 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
- 19 - | P a g e
Electrical Power System Analysis
NED University of Engineering and Technology
Lab Session 04
Department of Electrical Engineering
Connections on the simulator SEL-1/EV
Fig.2 – Series connection of two power transmission lines
- 20 - | P a g e
Lab Session 05
Electrical Power System Analysis
NED University of Engineering and Technology
Department of Electrical Engineering
LAB SESSION 05
TITTLE:
Studying the parallel operation of power transmission lines
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
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. GCB1/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 energy
increase, 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 only
for 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 of
two lines in parallel with each other.
PREPARING THE EXERCISE
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 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).
- 21 - | P a g e
Lab Session 05
Electrical Power System Analysis
NED University of Engineering and Technology



Department of Electrical Engineering
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
Interlinked
Condition voltage
measured at
the left
busway U1
(V)
Current of
line 1
I1 (A)
Current of
line 2
I2 (A)
Load current
IC (A)
Interlinked
voltage
measured
at the right
busway U2
(V)
Voltage
drop at
the 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)
- 22 - | P a g e
Lab Session 05
Electrical Power System Analysis
NED University of Engineering and Technology
Department of Electrical Engineering
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
- 23 - | P a g e
Electrical Power System Analysis
NED University of Engineering and Technology
Lab Session 05
Department of Electrical Engineering
Connections on the simulator SEL-1/EV
Fig.2 – Series connection of two power transmission lines
- 24 - | P a g e
Electrical Power System Analysis
Lab Session 06
NED University of Engineering and Technology
Department of Electrical Engineering
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
- 25- | P a g e
Electrical Power System Analysis
NED University of Engineering and Technology
Lab Session 06
Department of Electrical Engineering
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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- 26 - | P a g e
Electrical Power System Analysis
NED University of Engineering and Technology
Lab Session 06
Department of Electrical Engineering
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- 27 - | P a g e
Electrical Power System Analysis
Lab Session 07
NED University of Engineering and Technology
Department of Electrical Engineering
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.
f ( x)  x3  6x2  9 x  4  0
Also plot the curve
g ( x)  x
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
x0  6
f ( x)  x3  6x2  9 x  4  0
Also plot the curve
f (x )
vs
x
For 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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- 28 - | P a g e
Electrical Power System Analysis
NED University of Engineering and Technology
Lab Session 07
Department of Electrical Engineering
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- 29 - | P a g e
Electrical Power System Analysis
NED University of Engineering and Technology
Lab Session 07
Department of Electrical Engineering
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- 30 - | P a g e
Electrical Power System Analysis
Lab Session 08
NED University of Engineering and Technology
Department of Electrical Engineering
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 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)
- 31 - | P a g e
Electrical Power System Analysis
NED University of Engineering and Technology
Lab Session 08
Department of Electrical Engineering
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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- 32 - | P a g e
Electrical Power System Analysis
NED University of Engineering and Technology
Lab Session 08
Department of Electrical Engineering
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- 33 - | P a g e
Electrical Power System Analysis
Lab Session 09
NED University of Engineering and Technology
Department of Electrical Engineering
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)
f= 60Hz
No. of phases=1
f=60Hz
R=0.996 ohm/km
L=1.36 mH/km
C=0.85 exp(-8)
Length = 370km
Vm=125kV
f=60Hz
P=50MW
QL=0
Qc=0
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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- 34 - | P a g e
Electrical Power System Analysis
NED University of Engineering and Technology
Lab Session 09
Department of Electrical Engineering
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- 35 - | P a g e
Electrical Power System Analysis
NED University of Engineering and Technology
Lab Session 09
Department of Electrical Engineering
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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.
- 36 - | P a g e
Electrical Power System Analysis
Lab Session 10
NED University of Engineering and Technology
Department of Electrical Engineering
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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- 37 - | P a g e
Electrical Power System Analysis
NED University of Engineering and Technology
Lab Session 10
Department of Electrical Engineering
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- 38 - | P a g e
Electrical Power System Analysis
Lab Session 11
NED University of Engineering and Technology
Department of Electrical Engineering
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.
- 39 - | P a g e
Electrical Power System Analysis
NED University of Engineering and Technology
Lab Session 11
Department of Electrical Engineering
MATLAB CODE:
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- 40 - | P a g e