Method for Diagnosing the Conductor Broken Point of Grounding Grids in Substation Based on Measuring the Magnetic Induction Intensity
Zhibin Zhao · Gao dianya jishu · 2008
In order to test the broken faults of substations' grounding grids effectively,a new diagnosis method is proposed.A sine wave driving current whose frequency is different from power frequency is injected directly into grounding grid by two ground lead wires.According to the distribution characteristics of the surface magnetic induction intensities,the broken points of mesh conductors at joint or non-joint are diagnosed based on the Faraday electromagnetic induction law.The feasibility of the method is demonstrated by simulation computation used by the grounding analysis software package.Combining the practical EMI environment in substation,special testing and diagnosis systems are designed.Physical experiments show that its functions satisfy the testing needs.Experimental researches of the simulated grounding grids show that this method is feasible,the efficiency and precision of diagnosis are improved and the testing system can be used in engineering practice.