Research On Mechanism Of Electromagnetic Wave Propagation In GIS

The UHF method is widely used in online diagnosis of partial discharge in the gas insulated switchgear (GIS). The UHF method is based on the detection of the EM wave which is excited by the partial discharge. It's important to study the EM wave propagation characteristics in GIS.Based on finite element method (FEM), the propagation characteristics of EM wave which propagates in the GIS structure are studied. A high precision model of GIS for analyzing EM wave was established based on a practical GIS blueprint. Small details of manufacture features were considered in the study. The amplitude and frequency characteristics were carefully analyzed. To improve the efficiency of the analysis, different levels of simplification based on manufacturing features are carried out on the model. After the comparisons of the results, a series of simplifications have been carried out on the straight tank, T shaped link model, etc. The relationship between the leakage S parameter and the frequency is simulated. The EM wave which is excited by the partial discharge contains component of high-order mode. The propagation characteristic of the high-order mode is different from the main mode. High-order mode is also studied. We summarized systematic method of simplification of the calculation model. This method will significantly reduce the computation cost of the model. EM wave propagation characteristics in GIS are studied.In this paper, simplification rules of model of the GIS components are proposed. The insulator should be simplified, and no simplification should be carried out on the high tension conductor. Based on the simplification method, the common Mechanism of Electromagnetic Wave Propagation through the GIS components (Insulator, L-shaped connector etc.) is studied. The TEM wave which propagated in the L shaped and T shaped GIS tank will have a mode transformation.