Study on particle-induced corona discharge in Insulation Systems

Abstract

Gas Insulation System (GIS) is in popular use because of its high reliability and recovery ability. Existing particles in GIS deteriorate the GIS performance due to their higher dielectric constant or conductivity than the gas medium. The objective of study is to investigate characteristic of corona discharge induced by particles of different shapes. In our experiments, the particles were set stand on the lower electrode in a parallel electrode system. The corona discharge was detected by R m = 50 Ω or 500 Ω resistor. The corona inception voltage U i was calculated in the work to compare with the experimental results. The calculated U i is highest for the rounded-end particle, and lowest for the very-sharp end particle. U i is lower when the particle tip was sharper. Using the different R m values did not give so much difference for the U i , PD charge, and breakdown voltage U b . The calculated U i was higher than but followed the tendency of the measured one. In addition, the PD charges and number of pulses also followed the same tendency as U i . The PD charges were found to vary approximately linearly with the particle charges calculated by the numerical simulation. The breakdown voltage was close to each other for all particles. The tip of particles did not affect strongly on breakdown voltage. The difference between U b and U i was highest for the very-sharp end particle, and lowest for the rounded-end particle.