基于磁场分量波形分析的地下电缆弱磁探测技术

Weak Magnetic Detection Technology for Underground Cable Based on Waveform Analysis of Magnetic Field Components

在城市配电网改造中,许多直埋式的老旧电缆具体位置不明,这给巡线与定位故障电缆的工作带来了一定的困难。本文研究了一种基于磁场分量波形分析的地下电缆探测方法,也适用于海底电缆的探测。该方法使用磁通门传感器探测微弱的电缆磁场,磁场的3个相互垂直的分量被分别测量。为模拟真实的带电电缆,建立了一套模拟电缆运行的实验系统。实验结果显示,3个磁场分量中的至少2个分量存在特定的波峰与波谷,这些峰谷与电缆所在位置有关。利用2个分量波形的分布特征可准确判断电缆的位置。研究发现,对于交流电缆,磁场频率是采样频率的整数倍时,测量结果才是有效可读的。另外,本研究也利用仿真软件分析了电缆屏蔽层对于电缆产生磁场的大幅度削弱作用。

In the reconstruction of urban power distribution networks,the exact location of many old directly buried cables is unknown,which has brought certain difficulties to the work of patrolling and locating faulty cables. In this paper,a method for detecting underground cables based on the analysis of magnetic field component waveforms is studied. This method is also applicable to the detection of submarine cables. The method uses a fluxgate sensor to detect the weak cable magnetic field. Three mutually perpendicular components of the magnetic field are measured separately. To simulate a real live cable,an experiment system to simulate the operation of the cable is established. Results show that at least two of the three magnetic field components have specific peaks and valleys,and these peaks and valleys are related to the location of the cable. Using the distribution characteristics of the two component waveforms can accurately locate the cable. It is found that for AC cables,the measurement results are effectively readable when the magnetic field frequency is an integer multiple of the sampling frequency. In addition,this study also uses simulation software to analyze the significant weakening effect of the cable shielding layer on the magnetic field generated by the cable.