结合磁场延拓的变电站接地网腐蚀状态研究

Corrosion State of Substation Grounding Grid Combined with Magnetic Field Extension

为了更加高效合理进行变电站接地网腐蚀状态诊断,在现有借助地毯式探测接地网地表磁场强度进而分析接地网状态研究的基础上,提出一种结合磁场延拓技术应用于接地网腐蚀状态的研究方法。依据矢量格林恒等式,可知大平面边界各点磁场矢量积分关系,进而计算出平面内测量磁场与未知磁场的积分关系,通过剖分离散构建线性方程组,可求出未知磁场强度,达到磁场延拓的目的,即只需要测量接地网地表的部分磁场强度,就可以延拓重构得到整个接地网地表区域的磁场强度,进而为接地网故障诊断提供判据。采用该技术可以大大减少磁场强度的测量工作。通过仿真实验验证了所提方法的可行性,并在汉中司家铺110 kV变电站进行了接地网腐蚀状态检修试验,初步证实了磁场延拓技术应用于接地网故障诊断的可行性,证明该技术具有工程应用价值。

In order to find more efficient and reasonable conductors for corrosion defects in grounding grids of substations,based on the study of the ground magnetic field intensity and the analysis of grounding network conditions by using carpet detection grounding grids,a method combining magnetic field extension technology applied to the corrosion state of grounding grids is proposed. According to the vector Green identities,The vector integral relations of the magnetic fields at various points on the large plane boundary are obtained, and then the integral relation between the measured magnetic field and the unknown magnetic field in a large plane is found. Linear equations are formed by boundary dissection and dispersion,and the unknown magnetic field is solved to achieve the purpose of magnetic field extension.With the help of magnetic field extension technology,only part of the magnetic field intensity on the ground surface needs to be measured,and then the magnetic field intensity of the whole ground surface area can be reconstructed by continuation,which can provide criteria for fault diagnosis of the ground grid.Using this technology,the measurement of magnetic field intensity can be greatly reduced. The feasibility of the proposed method is verified by simulation experiments,and the grounding grid corrosion condition test is carried out at the 110 kV substation of the Hanzhong. The feasibility of applying the magnetic field extension technology to grounding grid fault diagnosis is preliminarily confirmed,which proves that the technology has the engineering application value.