Monitoring results of the effectiveness of surge arrester spacingson distribution line protection

摘要

Surge arresters were evaluated as a means of improving reliabilitynby reduction in 13 kV distribution line flashovers; five feeders werenextensively monitored for three years. Lightning-caused faults werendetected with the US National Lightning Detection Network,nmagnetic-field and optical sensors attached to fault recorders, andnlightning-activated camera systems. Three circuits had arresters addednon all phases with spacings of 40 m (every pole), 200 m, and 400 mnrespectively. Two other control circuits had no additional arresters.nThere was no discernible difference in the lightning performance of thencircuits outfitted with the different arrester spacings when line lengthnand lightning flash exposure are considered. Evidence indicated thatnmost of the faults were caused by direct strokes rather than inducednvoltage flashovers. The monitored circuits are in areas with relativelynheavy tree coverage which should reduce the number of direct strokes butncause higher induced voltages. In a surprising result, the circuit withnarresters installed on every pole had several lightning-caused faults