Study on VFTO and Its Electromagnetic Disturbance Characteristics Caused by GIS Isolation Switch Operation

Abstract

A large number of Gas Insulated Switchgear (GIS) has been put into use, which has caused serious electromagnetic interference. Especially for the isolation switch in GIS, it doesn’t have the ability to extinguish the arc when operating with small capacitive currents, resulting in contact between the contacts. The steep voltage waves rapidly fold back and forth in a compact pipeline space to form a very fast transient overvoltage (VFTO). In this paper, the finite integration method suitable for solving the theory of electric dipole antennas in electrically large-scale space electromagnetic fields is combined with CST MWS software to analyze and calculate the radiation interference of VFTO. The electric field strength at a position one meters away from the disturbance source in the simulation model is 4–12 kV /m, the magnetic field strength is 100–420A/m. By optimizing the physical structure of the transformer, the electric field strength is reduced to 2.2–2.5 kV/m, and the magnetic field strength is reduced to 29–116 A/m.