Theoretical and experimental studies on electromechanics of a metal particle in AC gas-insulated lines

Abstract

With the superiority of compactness, high reliability and the great transmission capacity, gas-insulated lines (GIL) has been widely used especially in certain regions. However, free metal particles may be brought into the closed structure inevitably. To study the problem of metal-particles pollution in AC GIL, the electromechanics of one spherical metal particle is analysed in a pragmatic situation of coaxial cylindrical electrodes. Based on the theory of fluid mechanics and considering the SF 6 /N 2 mixture's kinetic parameters, an analysis of the flow resistance in the process of particle movement is proposed. Furthermore, considering the random effects caused by roughness of metal surface, an analysis of the impacts between the particle and the conductor or the shell is also proposed by the collision theory of elastic mechanics. In addition, the experiments are executed in a coaxial cylindrical electrode model, and the experimental results validate the accuracy of this model. It is observed that there's an incremental impact of voltage on maximum height, but the applied voltage is not impacting the spread angle of particle's motion; with the change of radius, both the maximum height and spread angle have a maximum value; the maximum height of particles decreases with the SF 6 ratio and pressure.