气固电荷输运/倍增耦合的环氧介质沿面闪络概率分布仿真研究

Simulation of surface flashover probability distribution with gas-solid charge transport/multiplication coupling of epoxy resin

盆式绝缘子气固界面闪络引起电力系统关键设备绝缘失效是亟需解决的关键科学问题.气体的电子倍增与固体表层电荷输运的时间和空间尺度跨越多个量级,导致盆式绝缘子气固耦合界面放电物理机制不清楚.综合考虑三结合点电荷注入、固体表层电荷输运、电子在气体中发生剧烈碰撞电离等过程,建立气固耦合沿面闪络模型.基于气固耦合沿面闪络物理过程,提取了表征电介质固体表层电荷输运和气体碰撞电离特性的关键参数,建立了考虑随机变量的气固耦合沿面闪络仿真模型.仿真研究了空气中环氧介质沿面闪络电压的概率分布特性.当电荷输运随机变量为高斯分布时,得到了呈威布尔分布的闪络电压概率分布特性,仿真结果与实验结果一致.对比仿真与实验结果发现,闪络电压威布尔分布特征电压主要受控于气体介质,形状分布参数主要受控于固体介质.各个电荷输运随机变量对闪络电压形状分布参数的影响程度不同.研究结果阐释了闪络电压分布特性与电介质表层电荷输运和气体碰撞电离特性参数的关联.提供了一种仿真闪络电压概率分布特性的有效手段,可用于评估过电压作用下的气固界面失效概率.

The insulation failure of key equipment in power systems caused by gas-solid interface flashover of basin insulators is a key scientific problem that must be solved urgently.The time and space scales of gas electron multiplication and solid-surface charge evolution span multiple orders of magnitude,resulting in an unclear physical mechanism of the gas-solid coupling interface discharge of a basin insulator.A gas-solid coupling surface flashover model was established considering three junction point charge injection,solid surface charge transport,and gas collision ionization.The violent collision ionization in the gas caused by electrons emitted from the solid was taken as the surface flashover criterion.The key parameters characterizing surface charge transport and gas collision ionization were extracted based on gas-solid coupling surface flashover,and a model considering random variables was established to simulate the flashover voltage distribution of epoxy resin.The flashover voltage obeys the Weibull distribution when the charge transport parameters are Gaussian random variables,and the simulation results are consistent with the experimental results.By comparing the simulation and experimental results,it is found that the characteristic flashover voltage and distribution parameter are mainly controlled by the gas and solid media,respectively,and each charge transport random variable has a different effect on the distribution shape parameter.The Weibull distribution of flashover voltage consistent with the experimental results can be obtained by adjusting the standard deviation of charge transport random variables.This research explains the relationship between the Weibull distribution of flashover voltage and the charge transport and gas collision ionization parameters,providing an effective method to simulate the probability distribution characteristics of flashover voltage,which can also be used to evaluate the failure probability of the gas-solid interface under a certain voltage.