计及电磁干扰的接地网磁场诊断研究

Study on magnetic field diagnosis of grounding grid considering electromagnetic interference

埋设在地下的变电站接地网若是出现断裂等故障将影响设备和人身的安全性,而目前针对接地网的故障诊断仍然以定期开挖检测为主,具有盲目、低效等缺点,因此针对接地网的无损检测具有重要的应用前景。针对电网络诊断法诊断方程欠定的缺点,提出运用磁场反演法对接地网进行检测,并且考虑到接地网现场的电磁干扰问题,设计一套相应的硬件系统装置。首先对接地网进行分析,论述磁场反演法的可行性及其具体操作方法;其次,根据变电站接地网现场电磁干扰产生的特点,开发具有抗电磁干扰能力的磁场检测硬件系统;最后,通过在接地网模型上的实验和某变电站接地网的现场应用,验证该方法和系统的可行性和准确性。

The fracture failure of substation grounding grid buried underground endanger the safety of equipment and person.However,the current fault diagnosis for the grounding grid is still mainly based on regular excavation detection.This method has shortcomings such as blindness and low efficiency,so the nondestructive testing of grounding grids is of important application prospects.Aiming at the under-determined diagnosis equations defect of the electrical network diagnosis method,this paper proposes the method of applying magnetic field inversion to detect the grounding grid.Considering the electromagnetic interference problem of the grounding grid site,a corresponding hardware system device is designed.First,the grounding grid is analyzed,and the feasibility and specific operation of magnetic field inversion method are discussed.Secondly,according to the characteristics of electromagnetic interference in substation grounding network,a magnetic field detection hardware system with anti-electromagnetic interference ability is developed.Finally,the feasibility and accuracy of the method and system are verified through the experiment on the grounding grid model and the field application of the grounding grid in a substation.