基于三次谐波法的避雷器阻性电流测量方法研究

Research on detection method of MOA resistance leakage current based on third harmonic component

根据DL/T 987-2005标准所推荐避雷器泄漏电流标准波形,对阻性电流的测量电路进行了设计。整个系统采用电流传感器耦合的方法实现对泄漏电流的输出,然后将信号通过带通滤波器实现对全泄漏电流的三次谐波的提取,接着利用峰值检测电路实现对三次谐波的测量,同时结合三次谐波和基波之间的关系实现对基波分量的测量。整个论文对测量原理、六阶多重负反馈带通滤波电路以及峰值检测电路进行了详细地介绍。为了了解所设计电路的可行性,对整个电路进行了搭建和测量,由测量的结果可以看出,所设计的电路测试数据和输入数据之间的误差接近1%,这满足现场的测量要求。因此,所设计的电路可实现对避雷器阻性泄漏的测量。

The paper designs a circuit measuring resistive current,on the basis of leakage current standard waveform of the surge arrester recommended by the criterion of DL / T 987-2005. The way of current sensor interconnection is used by the system to achieve the output of leakage current,and the extraction of third harmonic of the total leakage current is realized through the technique of passing signals through bandpass filter. Then,the extraction of third harmonic is attained by the peak detection circuit,and the determination of the fundamental component is achieved through the relationship between third harmonic and fundamental wave. This paper introduces the measurement principle,six-order multiple negative feedback bandpass filter and the peak detection circuit in detail. The whole circuit is constructed and measured to understand the feasibility of the designing circuit. It is the deviation between test data and input data of the designing circuit in this paper derived from the measurement result approaches 1%,which meets with the acquirement of on-site measure. Consequently,the circuit designed by the paper could achieve the measurement of the arrester resistive leakage.