继电保护装置时变失效率估算及其区域性差异分析

相比恒定失效率,时变失效率在可靠性评估的准确度方面具有优势。文中针对电网继电保护装置失效特性,在区分偶然失效和老化失效的基础上,利用指数分布函数拟合估算继电保护装置的常值偶然失效率,利用Weibull、正态等分布函数拟合,估算时变的老化失效率,并利用可决系数比较拟合的优劣。基于区域电网继电保护装置现场失效情况形成数据,获得了该电网保护装置的时变失效率。仿真表明,实际电网的老化失效数据符合Weibull分布。针对该电网地理特点,分析了环境、区域因素对保护装置失效率的影响,结果表明该区域电网保护装置恒定失效率基本一致,老化失效率与自然气候相关。

Time-varying Failure Rate Estimation of Relay Protection Devices and Their Regional Differences Analysis

The time-varying failure rate(TFR) has advantages over the mean failure rate(MFR) in accuracy for reliability assessment.The estimation approach for the TFR of the relay protection device(RPD) with the field data is proposed.According to the feature of RPD failure,the data is first divided into random failure data and aging failure data.And then for the random failure data,the constant random failure rate(RFR) of RPD is drawn up with estimating exponential distribution function,for the aging failure data,aging failure rate(AFR) is estimated with the Weibull,normal,lognormal and Rayleigh distribution functions,and the best estimation is determined by the coefficient of determination.Simulation results show that the aging failure data of real power grid obeys the Weibull distribution law.Furthermore,the general TFR is,obtained with the addition of the RFR and AFR,estimated with the field data in a regional power grid.Finally,considering the geographical features of the power grid,environmental and regional factors,failure rate is calculated and the conclusion is drawn: MFR is basically consistent;AFR depends on climate.