一种采用Spearman相关系数与电流积分比率配合的直流配网纵联保护方法

A pilot protection method of DC distribution network based on coordination of spearman correlation coefficient and current integration ratio

为满足直流配网故障隔离可靠性与选择性要求,提出了一种采用斯皮尔曼相关系数与电流积分比率配合的直流配网线路纵联保护方法。首先,分析了直流线路在不同类型故障时暂态电流波形相关性的特点;其次,利用线路暂态电流波形在不同故障时的相关性差异构造保护判据,进行区内外故障判定、故障类型区分和故障区段定位,利用单极接地故障时同端电流积分比率的差异判断故障极;最后,在PSCAD上搭建直流配电网模型对所提保护方法进行仿真验证,所设置的故障区域、类型等与所检测故障一致,验证了方法的准确性与选择性。对该方法抗过度电阻与分布电容能力进行的评估结果验证了方法的可靠性。

To meet the reliability and selectivity of fault isolation in DC distribution network, a pilot protection of DC distribution network based on coordination of spearman and current Integration ratio is proposed.First, the characteristics of transient current waveform correlation of DC lines during different types of faults are analyzed.Then, the correlation difference of line transient current waveforms at different faults is used to construct protection criteria for determination of internal fault and external fault, fault type differentiation and fault section location;and the difference of current integration ratio at the same end is used to determine the fault pole in case of single pole ground fault.Finally, the proposed protection method is simulated and verified by building a DC distribution network model on PSCAD, and the fault areas and types set are consistent with the detected faults, which verifies the accuracy and selectivity of the method.Meanwhile, the method’s ability to resist over-resistance and distributed capacitance is evaluated to verify the reliability of the method.