Free moving particles in three-phase metal enclosed GIS

In this paper calculated field intensities in gas-insulated substations (GIS) are investigated. The existence and importance of areas with low field density for three-phase GIS are shown by means of specific utilization factors. Effects of these characteristic properties are discussed with respect to their influence on particle movement. Therefore, calculated and observed two-dimensional trajectories of moving particles complete this study. As an evident result which is also supported by PD measurements, the particle movement is minor for three-phase enclosures. The experimental set-up and the test-vessel are described.