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R5922 Pages: 2
PART ^
Answer any two full questions, each carries 10 marks.
a) Illustrate the methods used for improving string efficiency of overhead line (5)
insulators.

b) Derive the expressions for capacitance and insulation resistance of a single core
(5) cable.
a) Explain the advantages and disadvantages of corona. (5) b) With the aid of single line
diagrams, differentiate between mono polar and (5) bipolar types of HVDC links. Comment on
their use in the system.
a) Discuss the various conductor materials used for overhead lines. What are their (5) relative
merits and demerits?

b) Draw the configuration of FC+TCR. Explain its operation. (5)

PART D Answer any two full
questions, each carries 10 marks.

a) Derive the expression for Rate of Rise of Restriking Voltage. (5) 9) What factors cause
difficulty in applying circulating current principle to a power (5) transformer?
a) With a neat diagram, explain the arc extinctionin VCB. (5) b) Explain the working
of a surge diverter. (5)
a) Explain the operation of a microprocessor based over-current relay with the aid (5) of a block
diagram.
b) A single phase distributet# has a total impedan¢@df+ 700) At the far (5)

end ,ಔ current of 80A at 0.8 p.f. lagging and at mid-point ೩ cufrent of 100A at 0.6

p.f. lagging are tapped. If the voltage of the far end is maintained at 200V,

determine: (i) Supply end voltageVand (11) Phase angle between 0. THe load

power factors are with respect to the voltage at the far end. ****

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