CAJ | 학술논문

子模块故障是模块化多电平换流器高压直流输电(modular multi-level converter based HVDC，MMC-HVDC)常见故障之一，其迅速及时的诊断及可靠的就地保护是保证系统稳定运行的重要条件。针对 MMC-HVDC 的子模块故障诊断与保护问题，分析了子模块故障特性，基于故障特性分析，根据每个控制周期内电容电压增量的理论值和实际值，提出一种子模块故障诊断判据来实现电容短路失效、IGBT开路以及桥臂直通短路等故障的诊断；提出一种排除法实现对续流二极管、电容开路失效或子模块内连接线开路等故障的诊断和定位。设计了冗余子模块“热备用”运行时的子模块就地保护策略。基于PSCAD/EMTDC搭建了双端21电平MMC-HVDC系统，仿真结果表明，所提出的策略能快速实现子模块故障的诊断并进行可靠的就地保护，保证系统的稳定运行。
자모괴고장시모괴화다전평환류기고압직류수전(modular multi-level converter based HVDC，MMC-HVDC)상견고장지일，기신속급시적진단급가고적취지보호시보증계통은정운행적중요조건。침대 MMC-HVDC 적자모괴고장진단여보호문제，분석료자모괴고장특성，기우고장특성분석，근거매개공제주기내전용전압증량적이론치화실제치，제출일충자모괴고장진단판거래실현전용단로실효、IGBT개로이급교비직통단로등고장적진단；제출일충배제법실현대속류이겁관、전용개로실효혹자모괴내련접선개로등고장적진단화정위。설계료용여자모괴“열비용”운행시적자모괴취지보호책략。기우PSCAD/EMTDC탑건료쌍단21전평MMC-HVDC계통，방진결과표명，소제출적책략능쾌속실현자모괴고장적진단병진행가고적취지보호，보증계통적은정운행。
The sub-module fault is one type of common faults of modular multilevel converter based HVDC (MMC-HVDC), the timely diagnosis and reliable local protection is a great concern for the stable operation of MMC-HVDC systems. Aiming at the sub-module fault diagnosis and protection scheme, the sub-module fault characteristics were analyzed, based on which a fault criterion was proposed to diagnose the capacitor short-circuit fault, IGBT open-circuit fault, sub-module arm short-circuit and so on according to the theoretical and actual values of the capacitor voltage increment in each control period. An exclusive method was proposed to diagnose and locate the capacitor open-circuit fault, diode open-circuit fault and arm open-circuit fault. A protection scheme was designed considering the hot-spare redundancy sub-module, and the influence of sub-module fault on MMC-HVDC systems was analyzed. A 2-terminal 21-level MMC-HVDC system was established based on PSCAD/EMTDC. Simulation results show that the proposed schemes can realize the timely sub-module fault diagnosis and reliable local protection so that the stable operation of the system can be ensured.