Insulation Integrity of Three Phase Common Enclosure Gas Insulated Busduct with Particle Contamination under Image Charges

Metallic particles can be either free to move in the GIS or they may be tuck either to an energized electrode or to an insulator surface. If a metallic particle crosses the gap and comes into contact with the inner electrode or if a metallic particle adheres to the inner conductor, the particle will act as a protrusion on the surface of the electrode, and the voltage required for breakdown of the GIS will also cause a significant reduction of the breakdown voltage. When a particle is positioned near or on the surface of the enclosure, the image charges, due to the presence of the grounded enclosure, have to be considered. To determine the particle trajectories in a three-phase common enclosure Gas Insulated Bus duct (GIB) with Image Charge Effect an outer enclosure of diameter 500 mm and inner conductors of diameters 64 mm spaced equilaterally are considered. Aluminum, copper and silver particles were considered to be present on enclosure surface. The particle movement is also calculated at each instant in both radial and axial directions using Monte-Carlo Technique. The results of the simulation have been presented.