采用电流增量关联度的柔直配电线路双端量保护

Dual-terminal Protection of Flexible DC Distribution Lines Using Current Increments Correlation

针对有效提升多端柔性直流配电线路双端量保护动作速度以及抗干扰能力的问题,提出一种基于故障电流增量关联度比较的直流线路双端量快速保护方法。该方法利用直流线路两侧故障电流增量的变化特性,利用灰色T型关联度算法对故障电流增量的变化态势实测数据求解关联度,分别对正负极线路首末端电流增量序列的灰色T型关联度进行比较,实现线路故障的快速切除。通过在PSCAD/EMTDC平台搭建±10 kV多端柔性直流配电系统进行算例仿真分析,结果表明该保护方法可以准确判别区内外故障,保护实现流程原理简单,动作快速可靠,具有良好的适用性。

To improve the action speed and anti-interference capability of dual-terminal protection of multi-terminal flex-ible DC distribution lines,a rapid dual-terminal protection method for DC lines based on the comparison of fault current increments correlation is proposed.This method uses the changing characteristics of fault current increments on both sides of DC lines,solves the correlation by using a grey T-type relational analysis(GTRA)algorithm for the measured data of changing trends of fault current increments,and compares the GTRAs of current increment sequences at the head-terminal and end-terminal of positive and negative lines,respectively,thereby achieving a fast isolation of the line fault.The simulation analysis of an example is realized by building±10 kV multi-terminal flexible DC distribution system on the PSCAD/EMTDC platform,and results show that the proposed protection method can accurately recognize internal and external faults.In addition,the principle for its realization process is simple and its action speed is fast and reliable,indicating that it has excellent applicability.