In this paper, the reliability of 11/0.415KV town feeder transformers comprising four sub-feeders (Town, GRA, Water Works and industrial) located at Gwiwa Business Unit, Sokoto were studied. The cost implications of failed transformers were also studied, using the data collected from Central Bank of Nigeria (CBN, 2009). It was found that the total amount lost was N37,997,732.40, N16,522,245.88, N20,934,463.70 and N25,559,391.64 for Town, GRA, Water Works and Industrial respectively, over the four years. It is revealed that the approximate time any transformer under Town, GRA, Water Works and industrial feeder may be expected to function before fault or failure (Mean Time Between Failures, MTBF) is 9 months, 39 months, 20 months and 14 months respectively. It was also found that reliability of Town feeder is 52%, GRA79%, Water works 62% and Industrial feeder 50%. It was deduced that town and GRA are under semi-reliable conditions because they are subjected to load beyond their identified plate capacity.
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