Metallic particle contamination in a compressed gas insulated Busduct (GIB) system may lower the corona onset and breakdown voltage of the system considerably. These particles move randomly in a horizontally mounted GIB system due to the electric field, and this movement plays a crucial role in determining the insulation behavior of Gas Insulated sub stations. In order to determine the particle trajectories in a three-phase common enclosure Gas Insulated Bus duct (GIB) an outer enclosure of diameter 500 mm and inner conductors of diameters 64 mm spaced equilaterally are considered. Wire like particles of aluminum, copper as well as silver of a fixed geometry has been considered to be present on enclosure surface of a three-phase bus duct. Simulation is carried out for movement of metallic particles in a three-phase bus duct with reduced phase conductor diameter with a view to obtain optimum size of conductor for reliable operation. The work is carried out by reducing the original diameter of the conductor from 64mm to 54mm in steps of 5 mm. It is required to be done because competitive prices of several manufactures of GIS and cost of gas are increasing. The results will have a bearing on the extent of reduction of inner diameter of the HV electrode and the overall volume. This will provide information on the extent of particle movement for the same condition of the gas and particle geometry. At each reduced diameter the electric field on moving particle is calculated at each instant and radial movement is computed. The results show that the maximum flight of the particle is decreased as the phase conductor diameter is decreased as the net electric field of the bus duct conductor is decreased.
Metallic Particles, Electric Field, Gas Insulated Substations, Particle Contamination
