GIS中线形和球形金属微粒的运动行为和危害性

Motor Behavior and Hazard of Spherical and Linear Particle in Gas Insulated Switchgear

为了研究气体绝缘组合电器(GIS)中线形和球形两种典型微粒污染物运动行为和危害性,在实验室搭建了以实际126kV GIS设备为原型的2∶1缩比实验腔体,记录了球形和线形微粒在腔体内起跳、碰撞、运动与停止的全过程,对微粒的运动行为特征进行了描述和总结,对两类微粒最终停止位置以及不同停止位置处的危害性进行了统计分析,并通过不同微粒初始位置、不同外施电压下的多次重复性实验论证了实验结果的一般性。研究结果表明:球形微粒起跳后,径向起跳高度2mm左右;线形微粒起跳时,一端首先抬起,然后微粒站立跳动,径向起跳高度5mm左右。球形微粒与绝缘子碰撞会弹回,经过充分运动最终全部停止在外侧弱电场区;线形微粒与绝缘子碰撞作用易形成吸附,吸附于绝缘子的线形微粒易引起局部放电和诱发沿面闪络,危害性高于球形微粒。分析了重力、库仑力、电场梯度力及镜像力对两类微粒运动行为的影响,并论证了接触面镜像力所引起的静摩擦力差异是线形微粒与球形微粒在绝缘子表面吸附情况不同的主要原因。

In order to study the motion behavior and hazard of spherical particle and linear particle,a 2:1 scaled model cavity according to 126kV gas insulated switchgear(GIS)was set up.The whole process of jumping,collision,movement and stopping of spherical and linear particles was record and described.The hazards of the final stopping position of the two kinds of particles were discussed through multiple repetitive experiments.The results indicate that after the spherical particles jump,the radial height is about 2mm.As the linear particles jump,one end first lifts,the particles stand and jump,and the radial jump height is about 5mm.The spherical particles bounce back when colliding with insulators and they all stop in the weak external electric field.Linear particles adsorbed will easily cause partial discharges and induce flashover voltage along the surface.The effects of Coulomb force,gravity,electric field gradient and image force were analyzed.It is also demonstrated that the image force is the main reason for the final formation of particle adsorption on the insulator.