Shivaji University 2010-5th Sem B.E T.E(Electrical)- , Power System Analysis(New ) - Question Paper
This is 3rd year electrical engineering students regular paper for the year 2010, of the subject- power system analysis.
Seat
No. _
T.E. (Electrical) (Sem. - V) Examination, 2010 POWER SYSTEM ANALYSIS (New Course)
Day and Date : Monday, 29-11 -2010 Total Marks : LOO
Time : 10,00 a.m, to 1.00 p.m.
Instructions :1) Attempt any three questions from each Section.
2) Assume suitable data if necessary and state clearly the same.
3) Figures to the right indicate full marks.
SECTION - 1
1. A) A sub-station P supplies load of 15 MW ai 0.8 p.f. lag to station Q through
two overhead lines. The impedance of each line is (2+j4) Q and (3 + j4) n respectively. Calculate the power transmitted by each line. 8
B) Draw the single line diagram of a typical power system and discuss various power system elements. 8
2, A) A three phase, 50 Hz, 15 km long line has four conductors with I cm diameter
and spaced horizontally 1,5 m apart in a plane. The conductors in order are carrying currents Ia, Ib and Ic and the fourth wire, which is neutral, carries zero current. The currents are :
I. = -30 -H 50 A a J
= -25 + j 55 A Ic= 55 j 105 A The line is untransposed.
Find the flux linkage of the neutral. Also find the voltage induced in the neutral conductor. 8
B) Deduce an expression for line to neutral capacitance for a 3-phase overhead trans m i ss I on I i n e whe n the con ductors are symme trie al ly p laced. 8
3. A) Expl ai n van o us method s o f i m proving stri ng e fficicncy. 8
1-154
B) Explain various factors affecting corona and methods of reducing corona
effect. 8
4. Write short notes (any three): 18
1) Skin and proximity effect
2) Radial a.c. distribution sysLem
3) Types of line supports
4) Sag in overhead lines when supports are at equal levels.
SECTION - II
5. A) Explain [he terms propagation constant, velocity of propagation and
characteristic impedance as related to a long transmission line, 8
B) A 220 KV, 50 Hz? 3-phase overhead transmission line delivers a load of 75 MW at 0.8 p.f. lagging at the receiving end and has the following constant,
A = D = 0,9 Z0.6Q? B = 153.2 Z34,6, C = 0,0012Z90, Calculate sending end voltage, sending end current sending end p.f., sending end power, 8
6. A) Explain inter-sheath grading method of cable grading 8 B) Discuss different method of laying underground cables. 8
7. A) Form the YBus if the line series impcdance are given below. 10
Bus to Bus Impedance
1-2 0.15 + j 0,6 p.u
1-3 0,1 -rj 0.4 pru.
1 -4 0.15 +j 0.6 p.u,
2-3 0.05 + j 0.2 p.u. 3 -4 0.05 + j 0.2 p,u.
B) Compare Gauss-Seidal method and Newton Raphson method, 8
8. A) Discuss any one method of voltage control. 8
B) Explain synchronous condensers and phase advancers as power factor
impro vem ent equi pment. 8
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| Earning: Approval pending. |
