Coordination of MMCs With Hybrid DC Circuit Breakers for HVDC Grid Protection
Coordination of MMCs With Hybrid DC Circuit Breakers for HVDC Grid Protection
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DOI：
10.1109/tpwrd.2018.2828705
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发表时间：
2019-02
影响因子：
4.4
通讯作者：
Sheng Wang;Chuanyue Li;O. Adeuyi;Gen Li;C. E. Ugalde-Loo;Jun Liang
中科院分区：
文献类型：
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作者：
Sheng Wang;Chuanyue Li;O. Adeuyi;Gen Li;C. E. Ugalde-Loo;Jun Liang
提出了一种抑制直流故障电流和防止模块化多电平换流器臂过流的高压直流（HVDC）电网保护策略。该策略是基于半桥MMC和混合直流断路器（DCCB）的协调。这是通过允许MMC子模块在DCCB打开之前被临时旁路来实现的。一旦故障被DCCB隔离，MMC将恢复正常操作。所提出的方法的性能进行评估和比较时，MMC被阻止，当没有采取纠正措施。为了实现这一点，故障检测和歧视的算法，并讨论其对MMC旁路的影响。为了评估其有效性，所提出的算法在PSCAD/EMTDC中使用四端HVDC系统进行了演示。仿真结果表明，MMC和DCCB的协调可以显着减少直流故障电流和吸收的电流能量分别超过70%和90%，而保持MMC臂电流小。
A high-voltage direct-current (HVDC) grid protection strategy to suppress dc fault currents and prevent overcurrent in the arms of modular multilevel converters (MMCs) is proposed in this paper. The strategy is based on the coordination of half-bridge MMCs and hybrid dc circuit breakers (DCCBs). This is achieved by allowing MMC submodules to be temporarily bypassed prior to the opening of the DCCBs. Once the fault is isolated by the DCCBs, the MMCs will restore to normal operation. The performance of the proposed method is assessed and compared to when MMCs are blocked and when no corrective action is taken. To achieve this, an algorithm for fault detection and discrimination is used and its impact on MMC bypassing is discussed. To assess its effectiveness, the proposed algorithm is demonstrated in PSCAD/EMTDC using a four-terminal HVDC system. Simulation results show that the coordination of MMCs and DCCBs can significantly reduce dc fault current and the absorbed current energy by more than 70% and 90%, respectively, while keeping MMC arm currents small.