测量磁感应强度诊断变电站接地网断点

为有效检测变电站接地网导体断点故障,提出了一种新的诊断方法,即通过接地网的两根上引导体直接注入异频的正弦波激励电流,据电磁感应原理测量地表磁感应强度的分布特征,诊断接地网导体节点与非节点处的断点故障。利用接地网性能分析软件进行的仿真计算论证了方法的可行性。针对变电站实际的电磁干扰环境,设计了专用的检测诊断系统并用实验结果表明其性能满足检测需要。模拟接地网的实验研究表明诊断方法正确,提高了诊断的效率和精度,检测系统可用于工程实际。

Method for Diagnosing the Conductor Broken Point of Grounding Grids in Substation Based on Measuring the Magnetic Induction Intensity

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.