智能变电站继电保护装置寿命模型及其辨识方法

智能变电站继电保护系统在结构、构成元件及工作模式等方面都与传统保护系统存在很大差异，其寿命更长，可靠性更高，其寿命分布可能服从不同分布模型。对数正态分布模型由于其灵活性在电子产品寿命建模中得到广泛应用，其对可修复系统的寿命适应性更强。实际分析中，对数正态分布、Weibull分布、广义指数分布等常会混用，这种混用会导致寿命预估出现较大偏差而引起过度检修。首先建立了基于对数正态分布的寿命模型，然后通过修正极大似然函数法对截尾寿命数据进行不同模型间的辨识，并使用最小二乘法和平均秩次法进行参数估计，最终完成智能站继电保护装置寿命预估。通过实例验证了新模型预估的寿命较传统Weibull分布预估的寿命更接近实际。

A Life Model and Its Identification Method for Relay Protection Device in Smart Station

Relay protection system with long life and high reliability in smart station is different from the traditional protection system with respect to the structure， components and working mode， and its life distribution follows different distribution models. Lognormal distribution model is widely used in the life modeling of electronic products for its flexibility， and has higher adaptability for repairable system life. In the process of practical analysis， the lognormal distribution，Weibull distribution and generalized exponential distribution is used interchangeably， resulting in a large deviation in the life expectancy and over-maintenance. The paper establishes a life model based on lognormal distribution， uses maximum likelihood function method to discriminate models for censored data， and adopts the least square method and mean rank order method to give the parameter estimation， then implementing the life evaluation of the relay protection device in the smart substation. It is verified by examples that the estimated life with the life model is closer to the actual conditions compared with the traditional Weibull distribution.