Calculated particle trajectories in GIS of different designs and the verification by optical and acoustic measurements

In this paper single- and three-phase SF/sub 6/ gas-insulated switchgear (GIS) are compared with respect to the effects and the criticality of moving particles. To summarize the sensitivity of different GIS designs to moving particles, an evaluation of many calculated trajectories is presented. Some of the calculated results are verified by optically recorded trajectories of a particle moving in the laboratory GIS setup. As an evident result, which is also supported by acoustic measurements, the particle movement is minor in three-phase enclosures. Characteristic flight patterns demonstrate if the particle, depending on its size, contacts the high-voltage electrode or not. In the first case, a breakdown of the isolating distance gets predictable. The experimental setup, the test-vessel, and the modular components are described. The comparison is limited to rated voltages up to U=170 kV (AC, 50 Hz).