基于单相级联H桥变流器的配电网故障消弧与选线新方法  

A Novel Approach for Fault Arc Extinguishing and Feeder Selection in Distribution Networks Based on Single-Phase Cascade H-Bridge Converter

作　　者：郭谋发[1] 陈静洁[1] 张伟骏[1] 杨耿杰[1] 缪希仁[1] 

机构地区：[1]福州大学电气工程与自动化学院,福建省福州市350116

出　　处：《电网技术》2015年第9期2677-2684,共8页Power System Technology

基　　金：国家自然科学基金项目(51377023)~~

摘　　要：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。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.

关 键 词：配电网 有源接地 级联H桥 多电平变流器 故障消弧 选线保护 

分 类 号：TM77[电气工程—电力系统及自动化]