Suppression of Very Fast Transient over Voltages in Gas Insulated Substations using RC Filters

Abstract

this paper presents RC Filter based mitigation technique of Very fast Transient Over Voltages(VFTOs) in Gas Insulated Switch gear based substations. Gas Insulated Substations (GIS) are broadly used for transmission and distribution of electric power. In Gas Insulated Substations (GIS), through the switching events of disconnector switches a numeral restrikes will arise and this leads to generation of Very Fast Transient Over voltages (VFTO).  Due to frequent occurrences of VFTOs, the life of the insulation in the system will be reduced. It may lead to flashover. In this work to reduce these VFTOs, disconnector switches are rearranged by adding additional RC Filters as mitigating devices. Four Substations with different voltage ratings (765KV, 1000KV, 1200KV and 1500KV) are chosen to check effectiveness of RC filter as mitigating device in reducing VFTOs. Substation is modelled and results are presented in MATLAB/SIMULINK.