故障自清除型直流配电网新型双极短路故障元件识别方法

New Fault Element Identification Method of Bipolar Short-Circuit Fault in DC Distribution Network with Fault Self-Clearing

直流配电网内故障元件的快速、可靠识别及准确隔离是直流配电网的技术难点之一。针对故障自清除型换流器结合快速隔离开关的直流配电方式,该文提出一种无需检测线路两端电气量的故障元件识别方法。研究了基于网络结构及母线电气量的母线虚拟电压计算方法;利用母线虚拟电压在不同故障位置时的差异,研究直流线路故障的快速识别及定位方法,并提出利用换流器内子模块投切选择实现母线故障与线路端部故障的辅助识别方法。该故障元件识别方法仅利用换流器出口电流和母线电压实现全配电网的故障元件快速识别,而无需测量线路两端电气量,且不受配电网结构限制,兼顾了经济性和可靠性。

The rapid and reliable identification and accurate isolation of fault elements in DC distribution network is one of the technical difficulties restricting its development.Aiming at the DC distribution mode of fault self-cleaning converter combined with quick disconnecting switch,this paper presents a method of identifying fault elements without detecting the electrical quantity at both ends of the line.Firstly,the calculation method of bus virtual voltage based on network structure and bus electrical quantity is studied.Based on the difference of virtual voltage of bus at different fault positions,a fast identification and location method of DC line faults is studied,and an auxiliary identification method for bus faults and line end faults is proposed by using the switching selection of submodules in the converter.The fault element identification method only uses the outlet current of the converter and the bus voltage to realize the rapid identification of the fault element of the full distribution network,without measuring the electrical quantity at both ends of the line,and is not limited by the distribution network structure,taking into account the economy and reliability.