Investigation of PD pulse propagation characteristics in GIS

Concentrating on the TEM mode, the damping characteristics of partial discharge (PD) pulses propagating through each gas-insulated switchgear (GIS) component were investigated. As a result, it was discovered that frequency components above 500 MHz were remarkably damped by spacers, T-shape branches, and L-bends. Quantitative studies were undertaken on the frequency dependency of these damping characteristics. Then the equivalent circuits for analyzing the propagation characteristic of PD pulses were proposed. Furthermore, the validity of concentrating on the TEM mode was denoted by tests at a substation in service.