基于二维线性跟踪器的二次系统直流接地故障检测新方法

New Method to Detect DC Circuit Grounding Fault in Secondary Systems Based on Linear Tracker

在低频信号注入法的基础上,针对支路对地电容影响检测精度,以及小波检测方法存在的不足,提出了基于二维线性跟踪器的直流回路接地故障检测方法。将采集到的电压、电流信号送入二维线性跟踪器检测系统,通过调节跟踪器参数,提取低频信号和相应的微分信号,用最小二乘法拟合得到接地电阻值和对地电容值。仿真结果表明:该方法检测步骤简便、计算量小、测量结果准确,能全面反映支路的运行状态,为直流系统接地故障检测提供了一种新思路。

Based on two-dimensional linear tracker, a method to detect grounding fault in DC circuits of secondary system was proposed in allusion to the insufficiency of wavelet transform-based fault detection and the affect of the capacitance between DC branches and ground on fault detection accuracy. Firstly, inputting the collected low-frequency voltage and current signal into the two-dimensional linear tracker of the detecting system and by means of adjusting parameters of the tracker, the voltage-tracking signal and its corresponding first-order differential signal as well as the current-tracking signal were extracted; then the values of grounding resistance and grounding capacitance were obtained by least squares fitting. Simulation results show that the detection results of the proposed method are accurate and the operation state of the detected DC branch can be overall reflected, besides, the detection steps of the proposed method are simple and less calculation amount is needed.