FACULTY OF ENGINEERING
ERODE BUILDER EDUCATIONAL TRUSTS GROUP OF INSTITUTIONS
DEPARTMENT OF ELECTRICAL AND ELECTRONICS ENGINEERING
MODEL- I, MAY 2014
EE 2351 POWER SYSTEM ANALYSIS
Date : 06.05.2014 Time : 3 Hrs
Class / Sem: III EEE / 06 Max.Marks : 100
PART A 10 2 = 20 Marks
Answer all the questions
1. If the reactance in ohms is 15 ohms, find the p.u value for a base of 15
KVA and 10 KV.
2. Define transient stability and transient stability limit.
3. What is a slack bus?
4. What is meant by acceleration factor in GS method and best value?
5. What is power system stability?
6. State equal angle criterion.
7. Give the expression for critical clearing time.
8. Write the swing equation and explain the terms involved in it.
9. Define infinite bus in power system.
10. What is the use of swing equation? What are the methods used to solve
it?
PART B (5*16) =80 Marks
Answer all the questions
11. (a) Draw the reactance diagram for the power system shown in fig.
Neglect the Resistance and use base of 100MVA 220kv in 50 line. The
ratings of the Generator, motor and transformer are given below. (16)
Generator: 40MVA, 25KV, 20%; Motor: 50MVA, 11KV, 30%
- t/f: 40MVA, 33/220Kv, 15% - t/f: 30MVA, 11/220Kv, 15%
(OR)
(b) i) Write detailed notes about the per phase model of a three phase
transformer. (8)
ii) Write a short notes on :
i) Single line diagram.
ii) Change of base
iii) Reactance of synchronous machine (8)
FACULTY OF ENGINEERING
ERODE BUILDER EDUCATIONAL TRUSTS GROUP OF INSTITUTIONS
DEPARTMENT OF ELECTRICAL AND ELECTRONICS ENGINEERING
MODEL- I, MAY 2014
EE 2351 POWER SYSTEM ANALYSIS
Date : 06.05.2014 Time : 3 Hrs
Class / Sem: III EEE / 06 Max.Marks : 100
PART A 10 2 = 20 Marks
Answer all the questions
1. If the reactance in ohms is 15 ohms, find the p.u value for a base of 15
KVA and 10 KV.
2. Define transient stability and transient stability limit.
3. What is a slack bus?
4. What is meant by acceleration factor in GS method and best value?
5. What is power system stability?
6. State equal angle criterion.
7. Give the expression for critical clearing time.
8. Write the swing equation and explain the terms involved in it.
9. Define infinite bus in power system.
10. What is the use of swing equation? What are the methods used to solve
it?
PART B (5*16) =80 Marks
Answer all the questions
11. (a) Draw the reactance diagram for the power system shown in fig.
Neglect the Resistance and use base of 100MVA 220kv in 50 line. The
ratings of the Generator, motor and transformer are given below. (16)
Generator: 40MVA, 25KV, 20%; Motor: 50MVA, 11KV, 30%
- t/f: 40MVA, 33/220Kv, 15% - t/f: 30MVA, 11/220Kv, 15%
(OR)
(b) i) Write detailed notes about the per phase model of a three phase
transformer. (8)
ii) Write a short notes on :
iv) Single line diagram.
v) Change of base
vi) Reactance of synchronous machine (8)
12. (a) The fig given below shows a power system.
Bus 1 : Slack bus E
specified
= 1.05<0
Bus 2: PV bus |E|
specified
= 1.2 p.u, p
g
=3p.u
Bus 3: PQ bus P
L
= 4 p.u,,Q
L=
2 p.u
Carry out iteration of load flow solution by gauss seidal method.
Take Q limits of generator 2 as 0 Q < 4. Take =1. (16)
(OR)
(b) i) What is jacobian matrix? How the elements of jacobian matrix are
computed? (8)
ii) What is the need for LFA? Explain briefly. (8)
13. (a) A Generator is connected through a transformer to a synchronous
motor. The sub transient reactances of generator and motor is 0.15 p.u.
and 0.35 p.u. respectively. The leakage reactance of the transformer is
0.1 p.u. all the reactances are calculated on a common base. A three
phase fault occurs at the terminals of the motor when the terminal
voltage of the generator is 0.9 p.u. the output current of the generator is 1
p.u. and 0.8 p.f. leading. Find the sub transient current in p.u. in the fault,
generator and motor. Use the terminal voltage of generator as reference
vector. (16)
(OR)
(b) i) Derive the symmetric fault analysis of the system using bus
Impedance Matrix. (6)
ii) Derive swing equation. (10)
14. (a) With neat flow chart, explain how the transient stability study can be
made by modified Euler method. (16)
(OR)
(b) Describe the Runge kutta method of solution of swing equation for
multi machine systems. (16)
15. (a) Derive the expression for critical clearing angle.(16)
(OR)
(b) State and explain equal area criterion in connection with transient
stability analysis. What are the advantages and disadvantages of this
method? (16)
12. (a) The fig given below shows a power system.
Bus 1 : Slack bus E
specified
= 1.05<0
Bus 2: PV bus |E|
specified
= 1.2 p.u, p
g
=3p.u
Bus 3: PQ bus P
L
= 4 p.u,,Q
L=
2 p.u
Carry out iteration of load flow solution by gauss seidal method.
Take Q limits of generator 2 as 0 Q < 4. Take =1. (16)
(OR)
(b) i) What is jacobian matrix? How the elements of jacobian matrix are
computed? (8)
ii) What is the need for LFA? Explain briefly. (8)
13. (a) A Generator is connected through a transformer to a synchronous
motor. The sub transient reactances of generator and motor is 0.15 p.u.
and 0.35 p.u. respectively. The leakage reactance of the transformer is
0.1 p.u. all the reactances are calculated on a common base. A three
phase fault occurs at the terminals of the motor when the terminal
voltage of the generator is 0.9 p.u. the output current of the generator is 1
p.u. and 0.8 p.f. leading. Find the sub transient current in p.u. in the fault,
generator and motor. Use the terminal voltage of generator as reference
vector. (16)
(OR)
(b) i) Derive the symmetric fault analysis of the system using bus
Impedance Matrix. (6)
ii) Derive swing equation. (10)
14. (a) With neat flow chart, explain how the transient stability study can be
made by modified Euler method. (16)
(OR)
(b) Describe the Runge kutta method of solution of swing equation for
multi machine systems. (16)
15. (a) Derive the expression for critical clearing angle.(16)
(OR)
(b) State and explain equal area criterion in connection with transient
stability analysis. What are the advantages and disadvantages of this
method? (16)
