Improving Overhead HV AC Line Performance using Line Surge Arrestors under Lightning Conditions with Economic Analysis

摘要

In areas with high occurrence of lightning, lightning strokes play an important role in the performance of overhead HV AC lines. A single stroke can lead to back flashovers and the resultant surge on the conductor results in the protective devices operating to extinguish the power surge. This operation of the protective devices leads to consumer interruptions on the network, thus leading to a loss of production and negatively impacting the economy. Line Surge Arrestors are devices that can drain the power surge to ground, if placed adequately and in sufficient numbers. This paper determines the relationship between the magnitude of the lightning stroke, the tower top voltage and hence the backflashover voltage that would appear on the line, which would lead to power interruptions. Surge arrestors were modelled, using the MATLAB software, and the required number of surge arrestors per phase is thus determined that is required to drain the surge current down to earth and prevent power interruptions. Simulated results are presented in this paper.