Hybrid circuit breakers (CBs) are the most promising technology to isolate DC faults in modular multilevel converter (MMC)-based DC grids. However, they consist of expensive power electronic components that are sensitive to high overvoltage and overcurrent. This study proposes a hybrid high-voltage DC circuit breaker with an energy absorption branch of a parallel arrester structure, and investigates the possibility of reducing the fault current and the switching overvoltage. First, the basic principle of an energy absorption branch with a parallel arrester structure is presented. Then, the simultaneous and sequential insertion strategies are illustrated. Second, each strategy and each structure are combined separately to analyse their respective characteristics in reducing the overvoltage, the fault current, the energy absorption and the fault clearance time. The sequential insertion strategy of the proposed energy absorption branch is proved to have the best performance. Finally, the trade-offs between these four metrics are achieved through the non-dominated sorting genetic algorithm II (NSGA-II). A general method to determine the parameters of the proposed energy absorption branch from the Pareto front based on different preferences is provided. Simulations on PSCAD show that sequential insertion of the proposed energy absorption branch with the optimal parameters is able to suppress the switching overvoltage and limit the fault current to a relatively low extent simultaneously.

中文翻译：

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具有并联避雷器结构的能量吸收支路的混合式高压直流断路器

混合断路器 (CB) 是在基于模块化多电平转换器 (MMC) 的直流电网中隔离直流故障的最有前途的技术。然而，它们由对高过压和过流敏感的昂贵电力电子元件组成。本研究提出了一种具有并联避雷器结构的能量吸收支路的混合高压直流断路器，并研究了降低故障电流和开关过电压的可能性。首先，介绍了具有并联避雷器结构的能量吸收支路的基本原理。然后，说明了同时和顺序插入策略。其次，将每种策略和每种结构分别结合起来，分析它们各自在降低过电压、故障电流、能量吸收和故障清除时间。所提出的能量吸收分支的顺序插入策略被证明具有最佳性能。最后，通过非支配排序遗传算法II实现这四个指标之间的权衡(NSGA-II)。提供了一种基于不同偏好从帕累托前沿确定提议的能量吸收分支参数的通用方法。在 PSCAD 上的仿真表明，顺序插入具有最佳参数的能量吸收支路能够同时抑制开关过电压并将故障电流限制在相对较低的范围内。