a. The inverter of a DC convertor station has no load ideal DC voltage
275.53kV and DC current of 1.5kA. The actual DC voltage is 246.25 ١۷۸۰
Compute the reactive power requirement of the inverter (4.5 marks)

b. Explain the significance of SCR for planning and stability considerations of
HVDC links based on SCR (4.5 marks)

a. What are the factors to be considered in selecting site of earth electrode
(2
marks) b. Explain the problems of earth return currents during monopolar earth
return operation of a two terminal HVDC system. What are solutions to this
problem? (7 marks)

PART C

a. What is meant by bundling of conductors and explain the purpose of
bundling for EHV AC and HVDCtransmission (6 marks)

b. Explain the term Insulation coordination and its objective in EHV AC and
HVDC transmission systems (6 marks)

A three phase overhead line has conductor spacing of 5.5m and conductor
diameter of 3cm. Atrnospheric pressure is 740mm of Hg and temperature is
10° ©. Conductor surface irregularity factor is 0.9. Line is operated at 420kV
at
50Hz. Calculate the fair weather corona loss per phase by Peeks Formula.

(12 marks)
Explain the biological effects of strong electric field on human beings
standing on earth with bare foot. (12 marks)