Aiming at the issue that power flow controllers are vulnerable to damage under short-circuit fault conditions
thereby compromising power supply reliability
this paper proposes a two-stage current-limiting power flow controller tailored for flexible DC distribution networks. The proposed controller is designed to ensure safe operation during transient processes while enabling functional reuse. It integrates both power flow control and two-stage current-limiting capabilities: under steady-state conditions
it allows flexible adjustment of line power flow; during faults
it can rapidly switch operational states and implement adaptive current limiting based on fault types
making it suitable for flexible DC distribution networks with complex topologies. Finally
a six-terminal ring-shaped flexible DC distribution network model is established in PSCAD/EMTDC for simulation analysis. The results verify the effectiveness of the proposed power flow controller under various operating scenarios
including power flow control
multi-line coordinated control
fault current limiting
and transition from power flow control to current limiting mode
while also satisfying practicality and economic requirements.
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