MOVEMENT OF PARTICLES IN COMPRESSED SF6 GIS WITH DIELECTRIC COATED ENCLOSURE

In compressed GIS (gas insulated switchgear), the control of wire part icle contamination by dielectric coating of enclosure is demonstrated in this paper. Assuming that-a particle acquires free charge through a partial discharge, the modeling of particle movement when the inside surface of a horizontal section of GIS/GITL (gas insulated transmissio n line) enclosure is coated is described, Under an applied 60 Hz ac vo ltage, tile maximum height reached above the enclosure by a particle i s much lower for a coated than for an uncoated enclosure. When the app lied ac voltage varies, the maximum height reached depends on the magn itude of the applied voltage, phase and velocity at which the particle hits the enclosure, Typical results show that by coating the enclosur e, the maximum height reached by a wire particle in a coaxial system c an be reduced, thus inhibiting particle movement and minimizing the po ssibility of insulation breakdown.