基于热解动力学状态参量的GIS盆式绝缘子剩余寿命预测方法

Residual Lifetime Expectancy Prediction of the GIS Basin-type Insulators Based on Thermal Dynamics Analysis

如何实现盆式绝缘子的绝缘缺陷、老化程度和剩余寿命的有效评估,以避免绝缘失效和电力事故的发生,一直是电网运行密切关注和亟待解决的问题。盆式绝缘子的实际老化降解经历了一个化学反应过程,通过计算活化能、反应机理函数、指前因子等热解动力学状态参量,提出一种盆式绝缘子老化状态和剩余寿命的预测方法。以不同升温速率对某盆式绝缘子样本开展热失重实验,基于Flynn-Wall-Ozawa法得到热失重曲线台阶I的活化能;进一步通过修正反应级数,获得盆式绝缘子热失重曲线台阶I所遵循的反应机理函数,并利用Coast-Redfern法求得指前因子。最后,通过对Arrhenius速率方程的变形处理,建立盆式绝缘子的寿命预测方法,并讨论影响绝缘子使用寿命的关键因素。

How to effectively evaluate the insulation defects,aging degree and residual life of the basin-type insulators as to avoid occurrence of insulation failure and power accidents has long been a pending issue to be addressed by the power utilities.The aging and degradation of the basin-type insulators actually experience a gradual chemical reaction process,according to this philosophy,a methodology to predict the residual lifetime expectancy of the basin-type insulators was proposed based on extracting the state parameters of pyrolysis kinetics including the activation energy,the reaction mechanism function and the pre-exponential factor.Samples of the basin-type insulators were tested at different heating rates and the thermal decomposition characteristics were analyzed.Based on the Flynn-Wall-Ozawa method,the activation energy of Stage I process in the thermogravimetric curve was calculated.Then,the reaction mechanism function characterizing Stage I process was estimated by modifying the reaction order.Further,the response mechanism function was verified by the Coast-Redfern method and the pre-exponential factor was achieved.Finally,a method for residual lifetime prediction was established regarding the basin-type insulators under different casas,and the key influential factors affecting the lifetime were discussed.