After a DC line fault occurs in a VSC-MTDC system

the fault should be quickly cleared and the system should be restored to regular operation as soon as possible

to improve the reliability and flexibility of the system. This paper provides an overview of the fault-clearing circuits of the AC circuit breaker solution

the DC circuit breaker solution

and the submodule fault current self-clearing solution. Considering the application scenarios of DC overhead lines and DC cables

the technical characteristics of the three schemes in terms of equipment configuration and fault clearing/recovery strategies are discussed. Combined with the characteristics of the Zhoushan

Zhangbei

and Kunliulong projects and actual line fault situations

the actual application effects of the three schemes are introduced. Finally

a comparative analysis of each scheme is conducted from the perspectives of fault clearing and recovery time

power interruption

restart frequency

voltage reduction capability

and equipment cost. The research results can serve as a reference for selecting schemes and designing the functional aspects of VSC-MTDC engineering in the future.