Analysis of the Influence of Ultra-high Voltage Shunt Reactors on Transient Over-voltage of GIS Shell

The isolation switch in gas insulated switches (GIS) will generate transient over-voltage (TEV) on the casing when opening and closing the no-load small capacitance bus-bar, which is affected by the reactive power compensation device. This article applies partial element equivalent circuit (PEEC) to determine the frequency variation parameters of GIS impedance, and simplifies the calculation model equivalence of substation equipment to solve the transient over-voltage of GIS casing. The simulation analyzed the influence of the installation position of the parallel reactor, the inlet capacitance of the parallel reactor and series compensation, and the ground capacitance of the series compensation on the corresponding amplitude of the TEV main frequency. The results indicate that compared to the situation where parallel reactors are not installed, the TEV oscillation of GIS is more severe after the installation of parallel reactors in the substation. There is no significant change in the peak value of TEV, and the amplitude corresponding to the main frequency of TEV has significantly increased. As the distance between the parallel reactor and GIS increases, it continuously decreases. The variation of series compensation capacitance to ground will not have an impact on the main frequency amplitude of TEV.