Failure Modeling and Maintenance Decision for GIS Equipment Subject to Degradation and Shocks

In the traction power supply system (TPSS) of the high-speed railway (HSR), the traction load produces extremely severe load conditions. Therefore, Gas insulated substation (GIS) equipment served in TPSS of HSR suffers from both progressive degradation and random shocks. In this paper, the failure model of GIS equipment is considered as a competing failure mode multiplied by these two failure mechanisms. The degradation process and the shock process are described by gamma process and compound Poisson process, respectively, based on their temporal and spatial randomness. Furthermore, the maintenance strategy for GIS equipment in long-run time span with periodic inspections is developed. Under comprehensive consideration of optimal reliability and economic efficiency, indices associated reliability and maintenance cost are defined to evaluate the maintenance strategy performance in long-run time span for GIS equipment. The analysis results in the case study show that the inspection period and the shock threshold, as two maintenance decision parameters, can be optimized to achieve both high reliability and low maintenance cost. The influences of failure model parameters on optimized maintenance strategy are also revealed. © 2017 IEEE.