Abstract: When a DC short-circuit fault occurs in the modular multilevel converter high voltage direct current (MMC-HVDC) transmission system, it is characterized by fast rising rate and high peak value of the fault current, which can seriously endanger the safety of the grid. In order to suppress the fault current development and ease the contradiction between the opening current size of the HVDC circuit breaker and the fault removal time, it is necessary to configure current limiting devices on the DC side. First, this paper studies the working mechanism of different types of current-limiting devices under bipolar short-circuit faults, and explores the distribution of energy release sources, the evolution of transient energy and the influence of current-limiting device parameters on its current-limiting capability from the perspective of transient energy. Then, the calculation method of optimal configuration of fault current limiter and DC reactor parameters based on NSGA-Ⅱ optimization algorithm is proposed. Finally, a four-terminal bipolar flexible DC network model is built in the PSCAD/EMTDC simulation system, and the corresponding optimization scheme of current-limiting device parameters is designed for application scenarios with different electrical requirements. The simulation test results show that the optimization method can correctly configure the parameters of the current-limiting device and improve the efficiency of the current-limiting device in suppressing transient energy, which verifies the effectiveness and reliability of the proposed method.