电力系统及其自动化学报2018，Vol.30Issue(3)：8-16,9.DOI:10.3969/j.issn.1003-8930.2018.03.002
基于模块化多电平换流器的直流电网保护方案
Protection Scheme for DC Grid Based on Modular Multilevel Converter
摘要
Abstract
When a fault occurs on the DC side of a half-bridge modular multilevel converter(MMC),an anti-parallel di-ode will continue to provide a path for the short-circuit current,so the diode will probably be damaged due to excessive current.Accordingly,many protection schemes have been proposed by scholars considering the vulnerability of diode. To have a clearer understanding,the advantages and disadvantages of various schemes are summarized according to classification criteria such as shunt,current-limiting,capacitor voltage clamp and fast protection.First,the two stages of half-bridge MMC bipolar short-current fault are introduced,the equivalent capacitance of the equivalent fault circuit before sub-module blocking is compared and verified,and a definite conclusion is given.Second,a new fault current-limiting measure is presented;the capacitor voltage clamp technology is classified and summarized concisely,and the reason for the capacitor of half-bridge sub-module that cannot be charged after fault is discussed;moreover,a new type of self-blocking sub-module scheme is presented,which can reduce the use of diode. Finally,the protection scheme based on the Handshake principle is improved,which can clear the fault quickly.Note that different protection schemes have their own scopes of application,thus in order to form an economic and reliable protection scheme,different as-pects(e.g.,system capacity,investment budget,and load level)should be considered comprehensively and different schemes should be combined.The research in this paper can provide technical reference for subsequent applications of MMC technology to a multi-terminal DC transmission system.关键词
柔性直流/模块化多电平换流器/直流故障/电容电压箝位/保护策略Key words
flexible DC/modular multilevel converter(MMC)/DC fault/capacitor voltage clamp/protection strategy分类
信息技术与安全科学引用本文复制引用
薛士敏,张超,高博,陆俊弛..基于模块化多电平换流器的直流电网保护方案[J].电力系统及其自动化学报,2018,30(3):8-16,9.基金项目
国家自然科学基金资助项目(51577129,51207103) （51577129,51207103）
国家重点研发计划资助项目(2016YFB0900900) （2016YFB0900900）
天津市自然科学基金资助项目(14JCYBJC21000) （14JCYBJC21000）
