METALLIC PARTICLE CONTAMINATION IN A GAS INSULATED BUSDUCT (GIB) WITH SF_6 AND SF_6+N_2 GAS MIXTURES

摘要

Gas Insulated Substations (GIS) have found a broad range of applications in power systems because of their high reliability and small ground space requirement. Although, GIS have been in operation for several years, the problem of particle contamination needs full attention. In this paper a model has been proposed to determine the particle contamination in a 75kV, 100kV and 145kV Gas Insulated Busduct (GIB). Computer simulations of the motion of metallic particles were carried out on a GIB of 55mm inner diameter and 146mm outer diameter. Aluminium, Copper and Silver particles were considered to be present on enclosure surface. From the simulation it is observed that with pure SF_6 gas in Busduct and applied voltage of 100kV, the movements of Aluminium and Copper particles are 25.19mm and 5.63mm respectively. For 60% SF_6 and 40% N_2 gas mixture corresponding movements are 25.06mm and 5.68mm. For an applied voltage of 145kV with pure SF_6 gas movements of Aluminium and Copper particles are 38.97mm and 10.74mm. For the same voltage with 60%SF_6 and 40%N_2 gas mixture corresponding movements are 38.69mm and 10.26mm. It is observed from above results that with 60%SF_6 and 40%N_2 gas mixture, the GIS can be operated reliably.