Analysis of the Effect of Environmental Factors on Outage Rates of Overhead Distribution Feeders: A Case Study of Zaria Distribution Network

Abstract

The paper is aimed at analysing the environmental factors on the outage rates of the overhead distribution feeders. This was facilitated using daily outage data on the six 33kV feeders of the Zaria distribution system collected from the Zaria Transmission substation of the Power Holding Company of Nigeria (PHCN) for twelve months. Outage models were developed from where power losses due to the feeder outages were obtained. Frequent and delayed forced outages occur during the rainy season, the peak being in August and during harmattan, especially in October. There were relatively high outage rates during the hot season, the maximum occurring in May. Feeders 2, 3 and 6 were most frequently on forced outages. The causes of the high outage rates are attributable to damages done to the overhead lines due to heavy winds, thunder strikes and other disturbances associated with rain. Other reasons include animal-caused outages, increase in the simultaneous use of weather sensitive devices, trees and vehicular accidents. As a result, energy loss was found to be 2947.62GWh, which translates to high revenue loss if the entire nation is considered. The forced outage rates are mapped to external environmental factors while the scheduled outages are due to the intrinsic factors. The paper proposes recommendations for minimizing the outage rates and hence improving the performance of the feeders.