CAJ | 학술논문

为解决配电网单相接地故障消弧与选线保护难题,提出了一种配电网有源接地方式及其故障消弧与选线新方法.采用单相级联H桥多电平变流器直接接入配电网的中性点,配电网发生单相接地故障时,通过多电平变流器向中性点注入补偿电流,补偿流经接地点的故障全电流,并强制使故障相电压为0,实现故障消弧.经过一定延时后,逐渐减少注入电流至0,多电平变流器退出补偿,进行接地故障判断;若判断系统发生了永久性接地故障,则根据多电平变流器退出补偿前后的注入电流量及各出线零序电流改变量,进行选线保护.理论分析和仿真结果表明:该方法原理清晰、易于实现,具有可行性.
위해결배전망단상접지고장소호여선선보호난제,제출료일충배전망유원접지방식급기고장소호여선선신방법.채용단상급련H교다전평변류기직접접입배전망적중성점,배전망발생단상접지고장시,통과다전평변류기향중성점주입보상전류,보상류경접지점적고장전전류,병강제사고장상전압위0,실현고장소호.경과일정연시후,축점감소주입전류지0,다전평변류기퇴출보상,진행접지고장판단;약판단계통발생료영구성접지고장,칙근거다전평변류기퇴출보상전후적주입전류량급각출선령서전류개변량,진행선선보호.이론분석화방진결과표명:해방법원리청석、역우실현,구유가행성.
A novel approach with active grounding is proposed to solve the problems of ground fault arc extinguishing and line detection for distribution networks. The single-phase cascaded H-bridge multi-level converter is connected to the neutral point in distribution networks directly. When the single phase ground fault occurs, a compensating current is injected to neutral point by multi-level converter, fully compensating the fault current and controlling the fault phase voltage to zero, thus extinguishing the fault arc. After a certain delay, the ground fault judgment is executed when the compensating current is reduced to zero. If permanent ground fault is determined, the line detection is carried out to identify fault line according to changes of compensating current and zero-sequence current before and after the multi-level converter exiting. The theoretical analysis and simulation results show that this method has the advantages of clear principle, easy implementation and good feasibility.