Ampacity Calculations of Underground Power Cables With End Effects

This paper discusses the effects of short cable runs at the terminations on the current carrying capacity of the transmission circuit. Standard ampacity calculations assume an infinite length of the cable circuit, usually with a fixed laying configuration and unchanging environmental conditions. Even though this may be true for a majority of the cable lengths, the conditions at substations where the cable circuits terminate may dictate laying arrangements different from the one in the rest of the route. In this paper, the effect of changing cable arrangements at the circuit ends are discussed and the impact on cable rating is illustrated with numerical examples.