Research on Magnetically Coupled Resonant Detection Method for Breakpoint of Four Mesh Grounding Grid

Abstract

Magnetically coupled resonant technology is a novel method for solving the breakpoint locating of power grounding grid. But the method can only detect breakpoints of a single mesh grounding grid at present. In this paper, a magnetically coupled resonant detection method for four-hole grounding grid breakpoint is proposed. Firstly, the equivalent circuit model of the four mesh grounding grid with two types of breakpoints, namely edge branch and intermediate branch, is established. The input impedance and phase angle of the system are obtained by analyzing the equivalent capacitance and equivalent resistance in the model. Secondly, the magnetically coupled resonant physical process of grounding grid faults is solved via HFSS software. The magnetic field intensity and phase frequency characteristic curves of four mesh holes with different branches and positions of breakpoints and different corrosion degrees are studied, and an experimental system is built to verify the feasibility. The results show that under the condition of grounding grid buried depth of 0.5 m and input frequency of 1∼15MHz, and there is an inverse relationship between equivalent capacitance and distortion frequency, the phase angle is positively correlated with the degree of corrosion of grounding grid, and the error of signal distortion frequency can be positioned at 5%. This paper provides some ideas for the application of magnetic coupling grounding grid detection technology.