Reliability evaluation of distribution system through the analysis of time-varying failure rate

In this paper, the time-varying failure rate (TFR) of power distribution system components is extracted from the recorded failure data of KEPCO (Korean electric power corporation) in Korea and the reliability of power distribution system are evaluated using mean failure rate (MFR) and TFR. The TFR is approximated to bathtub curve using the exponential and Weibull distribution function. In addition, Kaplan-Meier estimation is applied to TFR extraction because of incomplete failure data of KEPCO. Also the reliability of the real power distribution system of Korea is evaluated using the MFR and TFR extracted from real failure data, respectively and the results of each case are compared with each other. As a result, it is proved that the reliability evaluation using the TFR is more realistic than MFR. In addition, it is presented that the application method at power distribution system maintenance and repair using the result of TFR.