Study on the propagation characteristics of partial discharge electromagnetic waves in 252kV GIS

The ultra-high frequency (UHF) electromagnetic waves excited by PD (Partial Discharge) in GIS(Gas-Insulated Switchgear) are attenuated as they are affected by the GIS structure. A sensor positioned over the resin sprue in mental flange of the insulator can receive UHF signals radiated from within the GIS, which may be a way to analyze the characteristics of partial discharge. To study the effects of the resin sprue on the propagation of UHF electromagnetic waves, the finite difference time domain (FDTD) method is used. The characteristics of the amplitude and other parameters of the UHF waves in the middle of the resin sprue are studied. The resin sprue can be seen as a rectangular waveguide and the results show that outside the rectangular waveguide, the field strength component that along the conductor is much larger than the components of other two directions. There are stronger signals radiating from the resin sprue when the size of resin sprue gets larger. What´s more, there are more low frequency components radiating from the resin sprue when the size of resin sprue gets larger.