A Reliability Prediction Model for the Relay Protection Device and Its Internal Modules Considering Thermal Effect

Abstract

AbstractThe failure of the internal module often leads to the failure of the relay protection device (RPD), which threatens the safe and stable operation of the power grid. At the same time, the thermal effect, which is expressed with temperature, is an important factor for module failure. However, there is few literatures engaged with the influence of temperature on the reliability of the whole PRD. This paper proposed the reliability models for the core modules and the RPD considering the thermal effect with temperature, combinges with the temperature-dependent Arrhenius model and the Weibull distribution model for the time-varying failure rate. In details, first, with the structure of the RPD, three main failures should be considered, namely the hardware failure, the software failure, and the human-induced failure. Combined with statistical data, it is determined that the hardware failure mainly considers the failure of the CPU module, power module and other modules.Secondly, with the Weibull distribution model for time varying failure rate and the Arrhenius model, an improved Weibull model for the failure rate of different modules considering temperature is established. Furthermore, combined with hardware, software & human-induced failure and repair rate, the reliability prediction model of the RPD is proposed. Finally, the case analysis shows the effectiveness of the proposed models.KeywordsThermal effectTime-varying failure rateArrheniusRelay protection deviceWeibull distributionCore module