Reliability Evaluation of Distribution System Based on Interval Type-2 Fuzzy System

The accurate estimation of distribution system reliability depends on requisite equipment failure data availability. Equipment failure rate is not deterministic because of lack of data availability and uncertainty of system failures. Failure rate is considered as a fuzzy number to incorporate the uncertainty of equipment failures. In this paper, interval type-2 fuzzy systems (IT2FS) are proposed to handle the twofold uncertainty of equipment failure, i.e., objective uncertainty and subjective uncertainty. Monte Carlo simulation (MCS) is employed to estimate equipment failure probability, and sampling approach is used to evaluate the failure possibility. The membership functions for equipment failure rate are approximated using this failure possibility. Fuzzy importance index (FII) is used to rank the impact of a component failure on reliability. The proposed assessment method is tested and validated on RBTS bus 2 reliability test system.