一种矿井漏电保护选线方法

A line selection method of mine leakage protection

针对目前矿井供电系统发生单相接地故障时选线准确率低的问题,根据故障线路与非故障线路零序电流波形存在明显差异的特点,提出了一种基于零序电流积分与改进Bhattacharyya距离算法的矿井漏电保护选线方法。该方法通过对故障后各线路首个1/4工频周期的零序电流数据进行积分递推处理,求出零序电流积分序列及其概率分布函数;利用改进的Bhattacharyya距离算法计算各线路零序电流积分序列之间的Bhattacharyya系数,以Bhattacharyya系数累加和求得的综合累加系数作为故障选线判据,并以同一时刻各线路电流采样值的乘积和作为辅助判据对母线故障进行判别。仿真结果表明,该方法能显著增大故障线路与非故障线路特征指标的差别,快速有效识别故障线路,适用于不同中性点接地方式,抗噪声干扰能力强,受不同故障工况的影响小,选线准确率高。

Aiming at problem of low accuracy of line selection when single-phase grounding fault occurs in mine power supply system at present,according to characteristics of obvious difference of zero-sequence current waveform between fault line and non-fault line,a line selection method of mine leakage protection based on zero-sequence current integration and improved Bhattacharyya distance algorithm is proposed.Zero-sequence current integral sequence and its probability distribution function are obtained by integrating and recursively processing zero-sequence current data of the first 1/4 power frequency period of each line after the fault.Bhattacharyya coefficient between zero-sequence current integral sequence of each line is calculated by the improved Bhattacharyya distance algorithm,and comprehensive accumulation coefficient obtained by accumulation of Bhattacharyya coefficients is used as fault line selection criterion.In addition,the sum of product of sampled current values of each line at the same time is used as auxiliary criterion to judge bus fault.The simulation results show that the method can significantly increase difference between fault line and non-fault line characteristics,quickly and effectively identify fault line,and is adapt to different neutral grounding modes with strong anti-noise interference ability,little influence by different fault conditions,and high accuracy of line selection.