摘要
直流系统接地故障检测中常用的低频信号注入法容易受到各支路电缆中存在的对地电容的影响。本文在其基础上提出一种基于复值小波变换的检测方法。该方法通过选取适当的复值小波函数,构造满足实时性要求的递推算法,从采样得到的离散支路电流信号中提取出由低频正弦信号发生器产生的低频电流,通过计算该电流信号中的阻性分量求得支路接地电阻,从而判断出故障支路。经过MATLAB仿真分析,证明这种方法可在对地大电容情况下准确提取出低频电流相量特征,正确判断出故障支路。
The method of low frequency signal injection, which is usually used to detect DC system grounding fault, is easily influenced by the capacitors between ground and each branch. This paper presents a detection method that is based on complex wavelet transform. Depending on selecting the suitable complex wavelet function and constructing the real-time recursive algorithm, this method extracts the low frequency current generated by the low frequency sinusoidal wave generator from the discrete current signal of the branch that is acquired by sampling. By calculating the value of the resistance current, the value of the branch's insulating resistance will be obtained and the faulting branch will be found. This method is proved by MATLAB simulation analyzing, it can get the phasor character of the low frequency current exactly in the case of high direct earth capacitance and the faulting branch will be found accurately.
出处
《中国电力》
CSCD
北大核心
2003年第11期12-14,共3页
Electric Power
基金
天津市自然科学基金(033601511)
关键词
直流系统
接地故障
复值小波变换
DC system
grounding fault
complex wavelet transform
