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Question Paper Code:: Reg. No.

This document contains a question paper for the subject Power System Analysis. It has 15 questions divided into two parts. Part A contains 10 short answer questions related to concepts like single line diagrams, bus impedance matrix, bus classification, reference bus, short circuit studies, bus admittance matrix, positive sequence impedance and steady state stability limit. Part B contains 5 long answer questions involving load flow analysis using G-Seidal and Newton Raphson methods, sequence networks, fault analysis, swing equation and stability criteria. The questions assess knowledge of various power system analysis concepts and techniques.

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Nithiya Maharajan
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58 views3 pages

Question Paper Code:: Reg. No.

This document contains a question paper for the subject Power System Analysis. It has 15 questions divided into two parts. Part A contains 10 short answer questions related to concepts like single line diagrams, bus impedance matrix, bus classification, reference bus, short circuit studies, bus admittance matrix, positive sequence impedance and steady state stability limit. Part B contains 5 long answer questions involving load flow analysis using G-Seidal and Newton Raphson methods, sequence networks, fault analysis, swing equation and stability criteria. The questions assess knowledge of various power system analysis concepts and techniques.

Uploaded by

Nithiya Maharajan
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PDF, TXT or read online on Scribd
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*X67585*

Reg. No. :

Question Paper Code : X 67585

B.E./B.Tech. Degree Examinations, NOVEMBER/DECEMBER 2020


Sixth Semester
Electrical and Electronics Engineering
ee 1351 A – power system analysis
(Regulations 2008)

Time : Three Hours Maximum : 100 Marks

Answer all questions


Part – A (10×2=20 Marks)
1. What is a single line diagram ?
2. What is bus impedance matrix ?
3. How are the buses classified in a power system ?
4. Why is reference bus necessary for power flow analysis ?
5. What is the need for short circuit studies ?
6. What is bus admittance matrix ?
7. Define positive sequence impedance.
8. Write the boundary conditions in single line to ground fault.
9.
10. Define steady state stability limit.

Part – B (5×16=80 Marks)

11. a) Find the bus impedance matrix for the system whose reactance diagram is
shown in fig. All impedances are in p.u.


(OR)
X 67585 -2- *X67585*

b) Determine the bus admittance matrix of the system whose reactance diagram
is shown below. The currents and admittances are given in p.u. Determine the
reduced bus admittance matrix after eliminating node-3.

12. a) The figure given below shows a three bus power system.


Bus (1) slack bus Especified = 1.05 ∠ 0°
Bus (2) PV bus |E|specified = 1.2 p.u. PG = 3 p.u.
Bus (3) PQ bus PL = 4 p.u., QL = 2 p.u.
Carry out one iteration of load flow solution by G-seidal method.
Take Q limits of generator 2 as 0 ≤ Q ≤ 4. Take a = 1.
(OR)
b) Write the procedure for load flow solution by Newton-Raphson method with
flow chart.

13. a) i) What is meant by sequence impedance ? Explain the sequence network of


an unloaded generator. (6)
ii) Derive the formula to determine the fault current for a line to line fault on an
unloaded generator. Draw an equivalent network showing the interconnection
between sequence of networks to simulate line to line fault. (10)
(OR)
*X67585* -3- X 67585

b) A three phase, 5 MVA, 6.6 kV alternator with a reactance of 8% is connected to


a feeder of series impedance of 0.12 + j0.48 ohms/phase/km. The transformer is
rated at 3 MVA, 6.6 kV/33 kV and has a reactance of 5%. Determine the fault
current supplied by the generator operating under no load with a voltage of
6.9 kV when a three phase symmetrical fault occurs at a point 15 km along
the feeder.

14. a) Derive the relationship for fault currents in terms of symmetrical components
when there is double line to ground fault. (16)
(OR)
b) A salient pole generator without dampers is rated 20 MVA, 13.8 kV and has
a direct axis sub transient reactance of 0.25 per unit. The negative and zero
sequence reactance are 0.35 and 0.1 per unit respectively. The neutral of the
generator is solidly grounded. Determine the sub transient current in the
generator and the line to line voltage for sub transient conditions when a single
line to ground fault occurs at the generator terminals with generator operating
unloaded at rated voltage. Neglect resistance. (16)

15. a) What is meant by Equal Area Criterion ? Explain it with a neat diagram and
prove it mathematically. Explain Equal Area Criterion as applied to the stability
study of fault and subsequent circuit isolation. (16)
(OR)
b) With necessary steps, explain the modified Euler method to solve swing equation
for a multi-machine system. (16)
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