This document appears to be an exam paper for a power system simulation laboratory course. It contains 17 questions related to power flow analysis, transmission lines, fault analysis and load-frequency control. The questions involve both manual calculations and computer simulations. Students are asked to calculate transmission line parameters, form bus admittance and impedance matrices, perform load flow analysis using Gauss-Siedel and decoupled methods, determine fault currents, simulate load-frequency response and control systems, calculate economic generation dispatch, and more.

1. Anna University, Chennai 600 025
ANNA UNIVERSITY: CHENNAI -600 025
B.E/B.TECH DEGREE EXAMINATIONS NOV/DEC 2014
(B.E. ELECTRICAL AND ELECTRONICS ENGINEERING)
SEVENTH SEMESTER
REGULATIONS : R-2008
EE2404- Power System Simulation Laboratory
Time 3 Hours Max: 100 Marks
1. A three phase transmission line has a per phase series impedance of 0.05 0.7 Ω
km
and per phase shunt admittance of 7 10 siemens
km. The line is 250 km long.
Obtain ABCD parameters of the transmission line. The line is sending 400 and 8
at 350 kV. Use medium T model.
a) Determine the value of .
b) Determine the voltage and current at receiving end and also compute voltage regulation and
efficiency
c) Verify the results using available program.
Aim & Circuit
diagram of T model
(15)
Manual
Calculation
(35)
Program
(30)
Results
(10)
Viva-
voce
(10)
Total
(100)

2. 2. A three phase transposed line composed of one ACSR, 143000 , 47 7⁄ Bobolink
conductors per phase with flat horizontal spacing of 11 between phases A and B, between
phases B and C. The conductors have a diameter of 4 cm and a geometric mean radius of 2
. The line is to be replaced by a three conductor bundle of ACSR, 477000
, 26 7⁄ Hawk conductors having the same cross sectional area of aluminum as the single
conductor line. The conductors have a diameter of 2.3 cm and a geometric mean radius of 1
cm. The new line will also have flat horizontal configuration, but it is to be operated at a
higher voltage and therefore the spacing is increased to 13 as measured from the center of
the bundles. The spacing between the conductors in the bundle is 40 .
a) Determine the capacitance and inductance per phase per km of the above two lines.
b) Determine the percentage change in inductance and capacitance in the bundle conductor
system
c) Verify the results using available program.
Aim & Circuit diagram
(15)
Manual
Calculation (30)
Program
(35)
Results
(10)
Viva-voce
(10)
Total
(100)

3. 1 2
3 4
100 km
120 km
100 km 110 km 150 km
3. A Four bus system is shown in figure 3.1.
Figure 3.1 Four Bus System
All transmission lines are characterized by a series impedance of 0.1 0.7 Ω
km and a shunt
admittance of 0.35 10 mho
km. Lines are rated at 220 kV. Use the values of 220 kV and
100 as base values.
a) Express impedances and admittances in per unit.
b) Compute the bus admittance matrix.
c) Verify the results with the available program.
Aim
(10)
Manual
Calculation (35)
Program
(35)
Results
(10)
Viva-voce
(10)
Total
(100)

4. 1 2
3 4
4. The figure 4.1 shows the one line diagram of a four bus system. Table 4.1 gives the
transmission line data of the system shown in figure 4.1.
Figure 4.1 Four bus System
Table 4.1 Transmission line data for the four bus system
Line ID Sending
Bus
Receiving
Bus
Resistance
in per unit
Reactance
in per unit
Half line charging
susceptance in per
unit
Rating
MVA
1 1 3 0.05 0.15 0 55
2 1 4 0.10 0.30 0 65
3 3 4 0.15 0.45 0 45
4 2 4 0.10 0.30 0 40
5 1 2 0.05 0.15 0 55
a) Compute bus admittance matrix assuming the line shown dotted is not connected.
b) What modification needs to be carried out to bus admittance matrix if the line shown dotted is
connected?
c) Verify the results with the available program.
Aim
(10)
Manual
Calculation (35)
Program
(35)
Results
(10)
Viva-voce
(10)
Total
(100)

5. 5) For the system shown in figure 5.1 compute the bus impedance matrix using Z-bus building
algorithm. Neglect the resistance of the lines and the reactances of the lines are indicated in
per unit in figure 5.1 on a 100 MVA base.
Figure 5.1. Three bus system
Aim
(10)
Manual
Calculation (35)
Program
(35)
Results
(10)
Viva-voce
(10)
Total
(100)
1 2
3
0.1j
0.1j 0.1j
0.25j 0.25j

6. 6) For the three bus system shown in figure 6.1 the relevant per unit line admittances on 100
MVA base are indicated on the diagram. Form bus admittance matrix and determine the
voltage at bus 2 and bus 3 after the second iteration using Gauss Siedel method. Assume
acceleration factor as 1.6. Use available software and print the output of the load flow
problem. Using the voltage solution of the converged power flow obtained from the available
program compute the sending end and receiving end line flow in each of the transmission line.
Solve the power flow problem using the available program for different value of acceleration
factors and plot the convergence characteristics.
Fig 6.1 Three bus System
Aim
(10)
Manual
Calculation (35)
Program
(35)
Convergence
Plot (5)
Results
(5)
Viva-voce
(10)
Total
(100)
Slack
Generator ‐j5 mho
‐j3 mho
‐j4 mho
1 2
3
60MW+j30MVAR
50MW+j25MVAR
25MW+j15MVAR
V1=1.02 p.u

7. 7. For the three bus system shown in figure 7.1 the relevant per unit line admittances on 100
MVA base are indicated on the diagram. Form bus admittance matrix and determine the
voltage at bus 2 and bus 3 after the second iteration using Gauss Siedel method. Assume
acceleration factor as 1.6. Use available software and print the output of the load flow
problem. Using the voltage solution of the converged power flow obtained from the available
program compute the sending end and receiving end line flow in each of the transmission line.
Solve the power flow problem using the available program for different value of acceleration
factors and plot the convergence characteristics.
Fig 7.1 Three bus System
Aim
(10)
Manual
Calculation (35)
Program
(35)
Convergence
Plot (5)
Results
(5)
Viva-voce
(10)
Total
(100)
Slack
Generator ‐j3 mho
‐j4 mho
‐j5 mho
1 2
3
50MW+j20MVAR
30MW+j5MVAR
25MW+j15MVAR
V1=1.03 p.u

8. 8. For the power system shown in figure 8.1
(i) Perform two iteration of N-R method using flat start and obtain the complex voltage
at bus 2.
(ii) Using the solution determine the real and reactive power mismatch at bus 2
(iii) Compute real and reactive power flow in the transmission line
(iv) Compute the line losses
(v) Obtain the slack bus generation
(vi) Verify the results with available software.
Figure 8.1 Two bus system
Aim
(10)
Manual
Calculation (35)
Program
(35)
Results
(10)
Viva-voce
(10)
Total
(100)
2
0.02+j0.06 p.u Slack
Generator
1
V1=1.02 p.u
50 MW
+j30 MVAR
150 MW+
j90 MVAR
75 MW
+j30 MVAR
j0.03 p.u j0.03 p.u

9. 9. For the power system shown in figure 9.1
(i) Perform two iteration of N-R method using flat start and obtain the complex voltage
at bus 2.
(ii) Using the solution determine the real and reactive power mismatch at bus 2
(iii) Compute real and reactive power flow in the transmission line
(iv) Compute the line losses
(v) Obtain the slack bus generation
(vi) Verify the results with available software.
Figure 9.1 Two bus system
Aim
(10)
Manual
Calculation (35)
Program
(35)
Results
(10)
Viva-voce
(10)
Total
(100)
2
0.01+j0.05 p.u Slack
Generator
1
V1=1.03 p.u
50 MW
+j30 MVAR
100 MW+
J60 MVAR
75 MW
+j30 MVAR
j0.02 p.u j0.02 p.u

10. 10. For the power system shown in figure 10.1
(i) Perform two iteration of Fast Decoupled Power Flow using flat start and obtain the
complex voltage at bus 2.
(ii) Using the solution determine the real and reactive power mismatch at bus 2
(iii) Compute real and reactive power flow in the transmission line
(iv) Compute the line losses
(v) Obtain the slack bus generation
(vi) Verify the results with available software.
Figure 10.1 Two bus system
Aim
(10)
Manual
Calculation (35)
Program
(35)
Results
(10)
Viva-voce
(10)
Total
(100)
2
0.02+j0.06 p.u Slack
Generator
1
V1=1.02 p.u
50 MW
+j30 MVAR
150 MW+
j90 MVAR
75 MW
+j30 MVAR
j0.03 p.u j0.03 p.u

11. 11. Consider the power system shown in figure 11.1 in which a synchronous generator supplies
a synchronous motor. The motor is operating at rated voltage and rated MVA while drawing
a load current at a power factor of 0.9 (lag) when a three phase symmetrical fault occurs at
its terminals. Calculate the fault current that flow both from the generator and the motor.
Verify the results with the available software.
Figure 11.1 A generator supplying a motor load through a transmission line
Aim
(10)
Manual
Calculation (35)
Program
(35)
Results
(10)
Viva-voce
(10)
Total
(100)
X’’=0.2 p.u.
50 MVA
20 kV
X=0.1 p.u.
50 MVA
20 kV/66kV
X=0.1 p.u.
50 MVA
20 kV/66kV
X’’=0.2 p.u.
25 MVA
18 kV
j10 ohms

12. 12. Consider the network shown in figure 12.1. For a line to ground fault at bus 2, determine the
fault current and MVA at faulted bus, post fault voltages, fault current distribution in
different elements of the network. Draw a single line diagram showing the above results.
Check the results obtained using available software.
Figure 12.1 Four bus system
: 100 , 20 , ′′
20%; 4%
, : 100 ,
20
345
; 8%
: 15%; 50% 100
: 100 , 20 , ′′
20%; 4%; 5%
Aim
(10)
Manual
Calculation (35)
Program
(35)
Single line
diagram (5)
Results
(5)
Viva-voce
(10)
Total
(100)

13. 13. Consider the system in which generator is connected to an infinite bus through a double
circuit transmission line as shown in figure 13.1. The per unit system reactances that are
converted in a common base, are also shown in figure 13.1. Assume the infinite bus voltage
as 1 0 . . The generator is delivering 1.0 p.u. real power at a lagging power factor of
0.98 to the infinite bus. While the generator is operating in steady state, a three phase bolted
short circuit occurs in the transmission line as shown in figure 13.1 very near to bus 4.
Assume 3.5 ⁄ . The fault is cleared by opening the circuit breakers at
the two ends of the line. Find the critical clearing time.
Figure 13.1 Four bus System
Aim
(10)
Manual
Calculation (35)
Program
(35)
Critical
Clearing time (5)
Results
(5)
Viva-voce
(10)
Total
(100)

14. 14. Consider the system in which generator is connected to an infinite bus through a double
circuit transmission line as shown in figure 14.1. The per unit system reactances that are
converted in a common base, are also shown in figure 14.1. Assume the infinite bus voltage
as 1 0 . . The generator is delivering 1.0 p.u. real power at a lagging power factor of
0.95 to the infinite bus. While the generator is operating in steady state, a three phase bolted
short circuit occurs in the transmission line as shown in figure 14.1 very near to bus 4.
Assume 4 ⁄ . The fault is cleared by opening the circuit breakers at the
two ends of the line. Find the critical clearing time.
Figure 14.1 Four bus System
Aim
(10)
Manual
Calculation (35)
Program
(35)
Critical
Clearing time (5)
Results
(5)
Viva-voce
(10)
Total
(100)

15. 15. It is proposed to simulate using the software available the load frequency dynamics of a
single area power system whose data are given below:
Rated capacity of the area=2000MW
Normal operating load=1000 MW
Nominal Frequency=50Hertz
Inertia constant of the area=5 seconds
Governor droop= 4%
Governor time constant =0.08 Seconds
Turbine time constant=0.3 seconds
Assume linear load frequency characteristics. The area has a governor control but not a load
frequency controller. The area is subjected to a load increase of 20 MW.
a) Simulate the load-frequency dynamics of this area using available software and check the
following
i) Steady State frequency deviation in Hertz. Compare with the manual calculation
ii) Plot the time response of frequency deviation in hertz and change in turbine power in
p.u. MW.
iii) Implement a suitable control to minimize the error.
Aim
(10)
Manual
Calculation (35)
Simulation
(35)
Results
(10)
Viva-voce
(10)
Total
(100)

16. 16. Simulate a load frequency dynamics of a two area power system. Both the areas are identical
and the system parameters are given below.
Rated capacity of the area=2000MW
Normal operating load=1000 MW
Nominal Frequency=50Hertz
Inertia constant of the area=5 seconds
Governor droop= 4%
Governor time constant =0.08 Seconds
Turbine time constant=0.3 seconds
Assume that the tie line has a capacity of 200 MW and is operating at a power angle of thirty
degrees. Assume that both the areas do not have load frequency controller. Area 2 is subjected to
a load increase of 20 MW.
a) Simulate the load-frequency dynamics of this area using available software and check the
following
i) Steady State frequency deviation in Hertz and tie line flow deviation in p.u.MW.
Compare with the manual calculation
ii) Plot the time response of frequency deviation in hertz.
iii) Implement a suitable control to minimize the error.
Aim
(10)
Manual
Calculation (35)
Simulation
(35)
Results
(10)
Viva-voce
(10)
Total
(100)

17. 17. In a four bus system the generating units connected at buses 1 and 2 are supplying a total
demand of 500MW connected at buses 3 and 4. The generating unit 1 and 2 have an
incremental fuel cost in dollars per megawatt hour as given below
0.008 8.0; 0.0096 6.4
Generation limits:
50 500
40 400
Calculate the economic loading of each unit to meet a total customer load of 500 MW. What
is the system and what is the transmission loss of the system? Determine the penalty factor
for each unit and incremental fuel cost at each generating bus. Verify the results with
available software. Also calculate the decrease in production costs of the two plants when the
system load is reduced from 500MW to 430 MW. Assume that the loss coefficients at the
specified load level of 500 MW in per unit on a 100 MVA base are given below
2
2
2 2
8.383 0.049 0.375
0.049 5.963 0.195
0.375 0.195 0.090
10
Aim
(10)
Manual
Calculation (35)
Program
(35)
Results
(10)
Viva-voce
(10)
Total
(100)

18. 18. Determine the economic generation schedule of three generating units in a power system to
meet the system load of 850 MW. The data of the generating units are given below:
Operating limits:
150 600
100 400
50 200
Production cost function in 10 RS/h
0.00128 6.48 459
0.00194 7.85 310
0.00428 7.97 78
Neglect transmission loss.
Aim
(10)
Manual
Calculation (35)
Program
(35)
Results
(10)
Viva-voce
(10)
Total
(100)

19. 19. Determine the economic generation schedule of three generating units in a power system to
meet the system load of 450 MW. The data of the generating units are given below:
Operating limits:
150 600
100 400
50 200
Production cost function in 10 RS/h
0.00128 6.48 459
0.00194 7.85 310
0.00428 7.97 78
Neglect transmission loss.
Aim
(10)
Manual
Calculation (35)
Program
(35)
Results
(10)
Viva-voce
(10)
Total
(100)

20. 20. Prepare the data for the network given in figure 20.1 and run EMTP. Obtain the plots of
source voltage, load bus voltage and load current following the energisation of a single phase
load. Double the source inductance and obtain the plots of the variables mentioned earlier.
Figure 20.1: Energisation of 0.95 power factor load
Aim
(10)
Data
Preparation (35)
Simulation
(35)
Results
(10)
Viva-voce
(10)
Total
(100)
56.34
cos wt
SRC BUS 1 BUS 12 BUS 13S BUS 13L
19.72mH
22ohm
6mH 2mH 6mH 0.05ohm
0.81
micro
farad
0.81
micro
farad