0 C6811 Pages: 3

Reg No.: Name:

APJ ABDUL KALAM TECHNOLOGICAL UNIVERSITY
SIXTH SEMESTER B.TECH DEGREE EXAMINATION, APRIL 2018
Course Code: EE306
Course Name: POWER SYSTEM ANALYSIS (EE)

Max. Marks: 100 Duration: 3 Hours
PART A
Answer all questions, each carries 5 marks. Marks
1 A 120 MVA, 19.5 kV generator has X = 1.5 percent and is connected to 9 (5)

transmission line by a star-delta transformer rated 150 MVA, 230/18 kV with X = 0.1
percent. If the base to be used in the calculations is 100۸۸۷۸, 230kV for the
transmission line, find the per unit values to be used for the transformer and generator
1680181065,

2 A single line to ground fault occurs at the terminals 01 ೩ 30 MVA, 11 kV generator. (5)
The positive, negative and zero sequence impedances in pu are j0.2, j0.2 and j0.05
respectively. Find the line currents under faulted conditions. Assume that the
generator is solidly grounded.

3 What are the main functions of load frequency controller in power system? (5)
4 Classify the various types of buses in a power system for load flow studies. (5)
5 The fuel cost functions for three thermal plants in Rs/hr. are given by, (5)

1 = 500 + 5,32 7
‏ین‎ = 400 + 5.57; +0.006P,”
‏ین‎ = 200 + 5.82, +0.009732
Find the power generated by each plant if the total demand 15 00۰

6 What do you mean by penalty factor as referred to economic operation of power (5)
system?

7 What are the factors affecting transient stability in power system? (5)

8 What is swing equation? Derive the expression for swing equation fora synchronous (5)

machine connected to an infinite bus.

PART B
Answer any two full questions, each carries10 marks.

9 (a) Two 11 kV, 3-phase generators rated 10 MVA, 25% and 20 MVA,40% operatein (6)
parallel. Calculate the short circuit kVA if a three phase short circuit occurs on the
feeder at point ‘F’ as shown in the figure.

ae

Calculate the reactance value of the feeder reactor to be included so that the short
circuit kVA is reduced by 50%.

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