A Failure Rate Model for Reliability Assessment of Ibadan Distribution Systems

Failure rate is one of the parametric indices used for assessment of electrical power system. It is defined as the inability of the system to perform its designated function adequately without interruption over a period of time. The rate at which distribution systems fail depends on many factors some of which are lack of maintenance, ageing, inexperience nature of the technical expert and government policies. This paper focuses on the development of a generalized failure rate model for assessment of reliability levels of Ibadan distribution system feeders. Ten selected feeders on Ibadan distribution systems were used to carry out the analysis. The outage data which included total no of faults on each of the distribution feeders and the corresponding time duration of faults for the two distribution systems were used as input parameters for computation of the failure rates. Curve fitting analysis was employed to develop a generalized model for the distribution system..The results of the model showed that Agodi feeder had the least failure rate of 0.1508 faults/sec because most of the faults on this feeder lasted for a short period of time. Onireke feeder recorded the highest failure rate of 0.2396 faults/sec because majority of the faults on this feeder persisted for a long period of time before being cleared. The result of this work can be used to provide a comprehensive analysis for the causes of distribution system feeders’ failure and the necessary policies to be formulated for enhancement of reliability improvement of Ibadan distribution system. Keywords: Failure rate, Faults,, Normal repair, Up and Down times,, Distribution system, Reliability