Impact of imperfections in GIS on their electric withstand

Results from experiments have been analyzed, in which the influence of particulate pollution on the withstand of gas-insulated systems (GIS) were studied. Special attention was paid to the prebreakdown phenomena in the presence of free or fixed metallic particles and to the impact which these particles have on the dielectric withstand of GIS under AC, DC, and impulse voltages. The main parameters were particle dimensions and materials and gas pressure. Both coaxial cylinder and concentric sphere electrodes were used.<>