Simulation And Experimental Study Of Propagation Characteristics Of UHF Electromagnetic Wave In GIS

As the main condition assessment tools for GIS fault diagnosis and positioning Partial discharge detection is very important. For its strong anti-jamming capability and high detection sensitivity, UHF method has been widely applied in partial discharge detection. Because of the variety of structures and components, propagation of UHF electromagnetic wave inside GIS is extremely complex. Through the establishment of GIS typical structures (straight cavity, L-structure, T-structure, CT, PT, pots-insulator, disconnector) simulation model, UHF electromagnetic wave propagation and attenuation characteristics are studied. Meanwhile, based on the existing experimental platform, this paper build a GIS combined structure simulation model. By comparing the experimental and simulation results, the accuracy of the simulation models are verified and propagation characteristics of UHF electromagnetic wave in complex structures are studied.Through the simulation and experimental study of UHF electromagnetic wave propagation characteristics in GIS,this paper found that when UHF electromagnetic wave propagates within a single structure or component, the structure can be considered as waveguide systerm (the components will have some impact on waveguide systerm), UHF electromagnetic wave spectrum showed typical mode wave distribution. After the typical structures or components (except for opening state disconnectors), UHF electromagnetic wave in the low frequency component (≤500MHz) does not decay basically, high-frequency component (>500MHz) attenuates significantly, even up to20dB. Through the opening state disconnector, UHF electromagnetic frequency spectrum’s low frequency component (0～500MHz) decays to zero, which consistents with circular waveguide theory. When UHF electromagnetic wave propagates in combined structure, since the short propagation distance and strong reflection, UHF electromagnetic wave shows shock attenuation trend. After combined structure, only1.25～2GHz frequency component attenuation is small, other frequency components significantly, partly decayed to zero.