Performance of SF6 GIB under the influence of power frequency voltages

A method based on particle motion is proposed to determine the particle trajectory in Gas Insulated Substation (GIS) or Gas Insulated Busduct (GIB). In order to determine the movement of a particle in a GIB, an inner electrode diameter of 40mm and outer enclosure diameter of 137mm was considered. Aluminium and copper wires of 0.25mm/10mm and 0.25mm/12mm were considered to be present on the enclosure surface. The motion of the wire (particle) was simulated using the charge acquired by the particles, the macroscopic field that the particle site, the drag coefficient, Reynold's number and coefficient of restitution. In order to determine the random behaviour of moving particles, the calculation of movement in axial and radial directions was done at every time step using rectangular random numbers. Typically for Aluminium wire for a bus duct voltage of 100 kV RMS, the movement of the particle (0.5mm / 8mm) for 2 Sec was computed to be 18.0337mm in radial and 424.4979mm in axial directions and the movement of the particle (0.25mm / 12mm) for 2 Sec was computed to be 22.4249mm in radial and 503.618mm in axial directions. Similar calculation is extended for a typical 200 kV (RMS) Gas Insulated Busduct