Performance of Gas Insulated Substations with Metallic Particle Contamination under the Influence of Various Types of Voltages

Compressed gas insulated substations (GIS) consist basically of a conductor supported on insulators inside an enclosure, which is filled with sulfur hexafluoride gas (SF₆). The voltage withstand capability of SF₆ bus duct is strongly dependent on field perturbations such as those caused by conductor surface imperfections and by conducting particle contaminants. The particles can be lifted by the electric field and migrate to the conductor or insulators where they initiate breakdown at voltages significantly below the insulation characteristics of the SF₆ gas. In this paper for optimized design of GIS by changing the inner and outer diameter to 40 mm and 137 mm is considered for analysis and compared with a single phase enclosure with outer diameter as 152 mm and inner conductor diameter of 55 mm with aluminum, copper and silver particles of size 10 mm in length and 0.25 as radius present on the enclosure. Very often, the operation of electrical equipment may seem normal, but under a certain combination of conditions, the impact of harmonics is enhanced, with damaging results. To study the behavior of metallic particles in the presence of harmonics different types of input voltage waveforms like square, triangular and asymmetric sine wave are applied to single-phase gas insulated busduct. The maximum movement of aluminum, copper and silver particles for applied voltages of 75 kV 100 kV, 132 kV, 145 kV, and 200 kV for triangular, square and asymmetric sine wave are determined. The results have been presented and analyzed.