Suppression Techniques of VFTOs generated by Switching Operations in UHV 1200KV GIS Substation

Abstract

In this paper, four distinct suppression techniques are used to minimize VFTOs in 1200KV UHV GIS substations. Restrike and prestrike events that occur during switching operations in a disconnector switch can lead to increased arcing currents and the generation of traveling waves. These high-frequency transients can decrease the dielectric strength of elements in the substation. The maximum value, frequency, and quantity of incidents between disconnector opening or closing operations are mainly caused by the development of VFTOs. The frequency operation of VFTOs is associated with the time taken for voltage collapse in sulfur hexafluoride gas and the movement of traveling waves within Gas Insulated Switchgear. To reduce VFTOs in a 1200KV UHV substation, four methods are proposed, and results are presented in periods of peak value, rise time, as well as settling period of oscillations. Simulations were performed on a 1200KV substation using MATLAB/SIMULINK.