Modeling of 275 kV Gas Insulated Substation and Analysis and Mitigation of Very Fast Transient Overvoltages

Abstract

Power demand in the modern era is more than ever before but there is the limitation of space availability in densely populated areas. Owing to the less space requirement Gas Insulated Substations (GIS) are expected to dominate the power transmission utility. A gas-insulated substation uses a superior dielectric gas, SF6, at moderate pressure for phase-to-phase and phase-to-ground insulation. The switching events in GIS result in the generation of Very Fast Transient Overvoltages (VFTO). By using PSCAD software, VFTO has been simulated in a 275 kV gas-insulated substation. The GIS components are represented using equivalent circuits. VFTO generated by simulating the switching events is analyzed using STFT and CWT analysis. Mitigation of VFTO using ferrite rings is evaluated by implementing the equivalent model in the substation model.