陈浩,张英敏,曾琦,陈可,周保坤.真双极MMC-HVDC系统线路过载紧急控制策略[J].电测与仪表,2019,56(4):107-114. Chen Hao,Zhang Yingmin,Zeng Qi,Chen Ke,Zhou Baokun.An Emergency Control Strategy for Line Overload in Bipolar MMC-HVDC System[J].Electrical Measurement & Instrumentation,2019,56(4):107-114.
真双极MMC-HVDC系统线路过载紧急控制策略
An Emergency Control Strategy for Line Overload in Bipolar MMC-HVDC System
With the development of DC circuit breaker research, it will be a feasible scheme to use DC circuit breaker to remove DC fault line in the future. However, circuit breaker operation may cause the line overload and endanger the safety of the whole DC system. In this paper, an emergency control strategy to prevent line overload was proposed by taking advantage of the independent control of positive and negative poles in bipolar MMC-HVDC system. Firstly, the active power distribution coefficient after opening the branch of the direct current system was deduced, and the line with the potential power limit can be found out. Then, the power margin of each line was maintained, and the new power reference value of the fault pole converter station was calculated by the power sensitivity matrix. Finally, the reduced power reference value was loaded into the healthy pole converter station, and the power constraints of the healthy pole converter station and the line were considered, which maximizes the stability of power exchange of AC/DC system and reduces the disturbance to the AC system. The strategy effectively avoids the power flow check and improves the speed of emergency control. The effectiveness of the proposed control strategy was verified by building a plurality of DC models in the PSCAD/EMTDC.
