To address the issues of secondary overcurrent impacts caused by blind reclosing after faults in flexible DC distribution systems

as well as slow recovery due to current fluctuations during the fault recovery process

this paper proposes a fault nature identification and recovery scheme for flexible DC distribution systems based on multi-port circuit breakers. First

the topology of a multi-port circuit breaker integrating a multifunctional power flow control module is analyzed. By merging redundant units with identical functions and similar structures

the integration level and economic performance of the device are improved. Subsequently

by actively injecting current signals into the faulty line through the control of this module

the fault nature is identified

and a dynamically adjustable weighted combination criterion is constructed to enhance identification reliability. During the fault recovery stage

the intrinsic power flow control capability of the module is utilized to suppress the transient current impacts arising from the voltage difference between the converter stations at both ends of the line

while enhancing the system’s dynamic response to power flow changes after recovery. Finally

a ring-type flexible DC distribution network model is established in PSCAD/EMTDC for simulation analysis

verifying that the proposed scheme features high reliability in fault identification

a high level of functional integration and wide applicability.