检测配电网电容电流及辨识高阻接地的新方法

对传统的注入信号检测配电网电容电流的方法进行了改进.通过判别注入信号在中性点产生的电压幅值来寻找系统谐振频率从而得到系统对地电容值,同时计算该处系统零序导纳值,实时监测线路绝缘状况.文中规定了注入信号的频率范围,使之不与电网频率重叠;提出了一种简单实用的信号处理算法,可有效抑制噪声对检测的干扰.该方法可以在工频干扰较严重的情况下准确检测系统电容电流,并能够有效辨识系统的高阻接地故障.

Novel Method for Measuring Capacitive Current and Distinguishing High-resistance Grounding of Distributing Network

Traditional methods for measuring the capacitive current by injecting signals are improved.By detecting voltage amplitudes of the injecting signals at the neutral point,the network resonance frequency used in calculating the system capacitance is determined so that the zero sequence admittance is obtained in monitoring the network insulation.The frequency range of the injecting signals is defined without overlapping the power network frequency.A practical signal-processing algorithm is proposed to suppress the noise interference.It is proved that the system capacitive current can be detected accurately and the high-resistance grounding can be distinguished effectively even with serious power-frequency disturbance.