基于高频暂态分量相关性的选择性漏电保护

Selective leakage protection based on correlation between high-frequency transient components

低压电网发生漏电故障时会产生丰富的暂态信息,利用各线路的高频暂态电流不受零序电抗器影响的特点,提出了基于数字信号处理中的相关函数理论的漏电故障检测方法。在一定数据窗内,用自相关函数计算线路的高频暂态能量,互相关函数分析各线路的相位关系,二者有机结合可有效地检测出漏电信号,实现选择性漏电保护。该方法综合考虑了各高频分量的幅值和相位,不受过渡电阻、系统参数、故障时刻等因素的影响。理论分析和仿真结果均表明,基于高频暂态分量相关度的漏电方法原理清晰,计算量小,是一种较为实用的新型漏电保护方法。

Abundant transient information is generated when leakage happens in low voltage network. As the high-frequency transient current of line is not influenced by zero-sequence reactor,a leakage detection method is proposed applying the correlation functions of digital signal processing. Within the data window,the auto-correlation function is used to calculate the transient energy and the cross -correlation function is used to analyze the relations between line phases,which are applied in leakage protection to effectively detect the leakage-fault. The amplitude and phases of each high- frequency component are considered synthetically while the transition resistance,system parameters and fault occurrence time do not influence the detection result. Theoretical analysis and simulation show that, this leakage detection method by correlation calculation of high- frequency transient components is clear in principle and easy in practice.