Download PTU (Punjab Technical University) B.Tech (Bachelor of Technology) / BE (Bachelor of Engineering) 2021 January EEE 7th Sem 71930 Power System Analysis Previous Question Paper
Total No. of Pages : 04
Total No. of Questions : 18
B.Tech. (EE / Electrical & Electronics Engg.) (2012 Onwards)
B.Tech. (Electronics & Electrical Engg.) (2012 to 2017) (Sem.7)
POWER SYSTEM ANALYSIS
Subject Code : BTEE-801
M.Code : 71930
Time : 3 Hrs. Max. Marks : 60
INST RUCT IONS T O CANDIDAT ES :
1 .
SECT ION-A is COMPULSORY cons is ting of TEN questions carrying TWO marks
each.
2 .
SECT ION-B c ontains F IVE questions c arrying FIVE marks eac h and s tud ents
have to atte mpt ANY FOUR questio ns.
3 .
SECT ION-C contains THREE questions carrying T EN marks e ach and s tudents
have to atte mpt ANY TWO questions .
SECTION-A
Write briefly :
1.
What are the advantages of ZBus building algorithm?
2.
What is necessity for power flow studies?
3.
What change will occur in the admittance matrix when a line is out of service?
4.
What change will occur in the admittance matrix when the turn ratio of a transformer
varies?
5.
Explain the significance of the phase shift operator `a' in the analysis of three-phase
circuits.
6.
Outline the advantages of working with per unit quantities.
7.
What is the meaning of kVA rating on a circuit breaker?
8.
What is the purpose of single line diagram?
9.
Who invented symmetrical components?
10. What is transient stability limit?
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SECTION-B
11. Compute the bus admittance matrix for the power system shown in Fig. 1.
j 0.4
G
G
1
2
j 0.1
j 0.2
j 0.25
j 0.2
j 0.3
G3
FIG. 1 : Power System Network
12. Categorize the various types of unsymmetrical faults and state the order of frequency of
occurrence of shunt faults.
13. Under what condition is the system stable according to equal area criterion? Discuss in
detail.
14. Discuss the possible solutions of the disturbed motion of a synchronous generator,
connected to an infinite bus, when subjected to a small disturbance.
15. For the power system shown in Fig. 2, convert all quantities to pu values on a system base
of 25 MVA. Assume a base voltage of 33 kV for the transmission line.
T
T
1
2
20 MVA
G
M 15 MVA
6.6 kV
11 kV
x = 0.12 pu
x = 0.15 pu
25 MVA
30 MVA
11/33 kV
33/22 kV
x = 0.08 pu
x = 0.10 pu
FIG.2 : Power System Network
SECTION-C
16. Calculate the load flow of the power system shown in Fig.3 using Newton-Raphson
method. [Note: Maximum iteration is 2]
4
2
0.08 +j0.30
3
5
1:1.05
1.05:1
j0.25
j0.25
j0.015
j0.03
P
V
V 4 = 1.05
4 = 5
0.1 +j0.35
5
V
5 = 0
4 = 1.05
0.04 +j0.25
3.7+j1.3
2+j1 j0.25
j0.25
1
1.6 +j0.8
FIG. 3 : Power System Network
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17. The zero sequence reactances for the various components of the power system shown in
Fig. 4 are as follows :
Generator 1 :
Star-connected 100 MVA, 11 kV, X0 = 0.08 pu with star point earthed
through a reactor of 3.0 .
Generator 2 :
Star-connected 50 MVA, 11 kV, X0 = 0.05 pu with star point isolated.
Motor star-connected 25 MVA, 6.6 kV, X0 = 0.05 pu with star point solidly earthed.
Transformers :
Between 1-2 : 100 MVA, 11/132 kV, delta-star with star point solidly earthed, X0 = 0.1
pu.
Between 3-4 : 50 MVA, 132/6.6 kV, star-delta with star point solidly earthed, X0 = 0.075
pu.
Between 4-5 : 50 MVA, 6.6/66 kV, star-star with both star point solidly earthed, X0=0.08
pu.
Between 6-7 : 50 MVA, 66/11 kV, delta-delta, X0 = 0.06 pu.
Between 7-8 : 75 MVA, 11/132 kV, delta-star with star point solidly earthed through a
reactor of 3, X0 = 0.06 pu.
Line 2-3 :
Zero sequence reactance X0 = 300
Line 2-8 :
Zero sequence reactance X0 = 250
Line 5-6 :
Zero sequence reactance X0 = 200
1
2
3
4
Generator 1
Motor
5
8
6
7
Generator 2
FIG. 4 : Single line diagram of power system
Draw the zero sequence network for the system.
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18. A three-phase, 50-Hz synchronous generator is delivering 0.9 pu real power to an infinite
bus via the transmission line shown in Fig. 5. All values shown in the circuit diagram are in
per unit on a common system base. A temporary three-phase fault occurs in the middle of
line 2. Determine the rotor angle position before the fault occurs. Assume H = 4.5
MJ/MVA.
1
2
X =j 0.3
T
Line 1
Infinite
bus
X'
X
= 0.2
d
d '
j
Line 2
F
X = 0
j .6
E' = 1.20
X = 0.2
t
j
V = 1.0 0?
B
FIG. 5 : Circuit Diagram
NOTE : Disclosure of Identity by writing Mobile No. or Making of passing request on any
page of Answer Sheet will lead to UMC against the Student.
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This post was last modified on 26 June 2021