Theoretical and experimental model for particle initiated breakdowns in GIS

Inadvertent failure of gas insulated system such as high voltage GIS is traced to a freak mechanism, in particle induced breakdown. While conducting (metallic) particles cause a direct breakdown of the gaseous insulation due to a high degree of non-uniformity of electric fields surrounding them, dielectric (insulation) particles give rise to disruptive discharges due to surface charges acquired by them in the strongly divergent electric field in their vicinity. The deleterious effects of particles are too well known to be enumerated. Since it is not always possible to fabricate GIS without parasitic floating and fixed particles, and scavenging the particles bordering on microscopic dimensions is very difficult, study of the particle aided breakdown study acquires particular significance in GIS. The effect of particles of either kind being the same; the reduction in the dielectric strength of the system, every effort should be made to either prevent outages due to them or workout means of stabilising the system in their presence. The present paper, attempts to make a small contribution in this direction