Power flow controllers and circuit breakers are important devices in a DC grid, and combining them and expanding their ports can save many components. This paper proposes an integrated multiport DC power flow controller with a DC circuit breaker that can achieve power flow control and fault removal on multiple DC lines during steady and fault states, respectively. First, the device's topology based on modular multilevel converters is proposed, and the principles of power flow control and self-power balance based on bridge arm voltage are introduced. Second, it is improved by adding a fault removal capability. The equivalent circuit and fault currents in different time sequences are analyzed, and the component parameter selection method is designed. Third, in the PSCAD/EMTDC, the power flow control and fault removal capabilities are verified using three conditions: flow control, line fault, and bus fault. Finally, the number of components and steady-state losses are analyzed. Overall, the proposed device has power flow control and fault removal functions as well as a certain limiting effect on the fault current, which greatly reduces the system construction cost.

中文翻译：

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带直流断路器的集成多端口直流潮流控制器

潮流控制器和断路器是直流电网中的重要设备，将它们组合并扩展其端口可以节省许多组件。本文提出了一种带有直流断路器的集成多端口直流潮流控制器，可以分别在稳态和故障状态下对多条直流线路实现潮流控制和故障排除。首先，提出了基于模块化多电平变换器的装置拓扑结构，并介绍了基于桥臂电压的潮流控制和自功率平衡的原理。其次，通过增加故障排除能力对其进行改进。分析了不同时序的等效电路和故障电流，设计了元件参数选择方法。三、在PSCAD/EMTDC中，潮流控制和故障排除能力通过三个条件进行验证：流量控制、线路故障和总线故障。最后，分析了元件的数量和稳态损耗。总体而言，该装置具有潮流控制和故障排除功能，并对故障电流有一定的限制作用，大大降低了系统建设成本。