Redundancy Protection for Sub-module Faults in Modular Multilevel Converter

作者：Zheng Xu · 发表于：Dianli xitong zidonghua · 年份：2011 · 被引用次数：18 · 研究领域：HVDC Systems and Fault Protection、High-Voltage Power Transmission Systems

The operation mechanism of modular multilevel converter(MMC) is described.Different kinds of sub-module faults in MMC are analyzed,which may cause the oscillations of DC voltage and current and finally cause the outage of the converter.Different redundancy protection methods(RPMs) to deal with sub-module faults in cascaded H-bridge converter are compared,and then a new RPM suitable for sub-module faults in MMC is proposed.In this method,one or few redundant sub-modules are put in hot stand-by state in order to replace fault sub-module rapidly,while the others are in cold stand-by blocking state so as to protect the insulated gate bipolar translators(IGBTs) from current flowing in them.Time-domain simulation results show that the proposed RPM enables MMC based voltage source converter based high voltage direct current(VSC-HVDC) system to recover from sub-module faults without interruptions of power delivery.