connected in series with an underground cable having inductance of 0.185mH/km

and 285nF/km. Calculate the values of transmitted and reflected waves of voltage

and current at the junction due to a voltage surge of 110kV travelling to the junction:

(i)

Along the line towards the cable;

(ii)

Along the cable towards the line.

4.2 A rectangular surge of 2 micro seconds’ duration and magnitude of 100kV travels

along a line of surge impedance 500ohms. The latter is connected to another line of

equal impedance through an inductor of 0.5mH. Calculate the maximum value of

surge transmitted to the second line.

4.3 Discuss the origin of switching surges.

4.4 What is the disadvantages of gap type surge arrestors over gapless MOV type

(reason why they are being phased out)

4.5 What is BIL and SIL, what are standard or typical wave shape duration?

4.6 What line design and construction factors can negatively impact on the lightning

performance of an overhead line?

4.7 “the leakage resistance of a counterpoise should be lower than its surge impedance”

Why?