Influence of Gas Insulated Switchgear Configuration Components on UHF PD Signals

Partial Discharge (PD) measurement is one of the main methods for condition monitoring of Gas Insulated Switchgears (GIS). Internal Ultra High Frequency (UHF) sensors can be applied for capturing PD propagated electromagnetic signals within the GIS. PD sensor placement inside the GIS is one of the main challenges for designing the online PD measuring system. For this aim, the impacts of different GIS components on the propagated PD electromagnetic wave should be studied. In this paper, different PD sensor position angles (with respect to PD sensor), are applied for investigating their sensitivity on the measuring PD electromagnetic wave. Two distinguishable parameters from the calculated PD electromagnetic waves, the first rated electric field and the signal’s power over the two frequency ranges (0.3-2 GHz and 0.3-3 GHz) are used for analyzing and quantifying the calculation results. The impacts of different enclosure diameters, different types of spacers, and various disconnector contact gap distances (under different voltage levels) on this wave propagation are studied. Additionally, the two standard GIS busbar profiles, named: L-shape and T-shape; are discussed in this paper. The results of this study show that the attenuation degree of the measured PD EM waves is strongly influenced by the busbar dimensions and its components configurations. The GIS busbar designer can employ these results to select the proper PD sensors and their installation locations.