Minimization of Movement of Free Particles in Gas Insulated Busduct using Coated Electrodes under Impulse Voltage

Abstract

Abstract. Presence of metal particles which can conduct can weaken the dielectric strength of sulphur hexafluoride as much as 90% in transmission and switching equipment. These particles can move in the electric field or can settle on the surface of the conductors, thereby increasing the local surface fields. The movement of such particles, lying within the surface of the enclosure is arbitrary in a horizontal coaxial system. Several methods were used for controlling and limiting the impact of these particles, one of them being coating the inner surface of the outer enclosure with a thin layer of dielectric. This increases the electric field required to rise a particle lying within surface of enclosure. GIS should be able to withstand any transient over voltages caused due to switching surges or lightning and protect the transmission lines and other electrical apparatus without breakdown. Lightning Impulse Voltage of 1050 kV superimposed on Power frequency voltages of 75 kV. 100 kV, 132 kV, 145 kV, and 200 kV are applied to a single Phase GIB and the dynamics of the Aluminum, Copper and Silver particles is studied. The pattern of the particle movement in radial and axial directions is observed with Monte Carlo Simulation and also without using Monte Carlo Simulation.