直流微电网故障保护技术研究综述

Review on Fault Protection Technologies of DC Microgrid

直流微电网故障保护是交直流混合微电网发展的一大挑战,因此,围绕目前直流微电网故障保护中故障特性分析、故障检测与定位方法、故障隔离方案这3个关键技术的最新进展进行了综述和分析。首先,总结了直流微电网常用的拓扑结构、接线形式以及端口换流器类型。其次,分别分析了基于两电平和模块化多电平换流器的直流微电网特性,归纳了故障直流微电网直流线路和换流器的暂态建模方法。然后,分别整理了故障检测与故障定位中的常用方法,从时域和频域两个方面总结了故障检测方法,并从无源和有源两个方面总结了故障定位方法。接着,分析了交流断路器、直流断路器+直流限流器、具有自清除能力的模块化多电平换流器和多功能一体化拓扑结构共4种故障隔离方案。最后,总结了直流微电网故障保护关键技术的研究进展,并给出了直流微电网故障保护下一步研究的几点建议。

Fault protection of DC microgrid is a major challenge for the development of AC-DC hybrid microgrids.Thus,this paper focuses on the review and analysis of three key technologies in fault protection of DC microgrid.And the three key technologies include the fault transient characteristics analysis,fault detection and location methods,and fault isolation schemes.Firstly,the topologies,wiring forms and terminal-converters of DC microgrid are summarized.Secondly,the transient characteristics of the DC microgrid based on two-level and modular multilevel converters are analyzed,and the transient modeling methods of DC microgrid transmission lines and converters are also summarized.And then,the common methods of fault detection and fault location are sorted out respectively.The fault detection methods are divided into time-domain and frequency-domain fault detection methods.While the fault location methods are divided into passive fault location and active fault location methods.Next,four fault isolation schemes,including an AC circuit breaker scheme,a DC circuit breaker+DC fault current limiter scheme,a submodule in MMC scheme,and a multifunctional integration topology scheme,are analyzed.Finally,the research of key technologies for fault protection of DC microgrid is summarized and suggestions for the future research for fault protection of DC microgrid are given.