Abstract: The flexible DC power grid with overhead lines is prone to transient faults, so it is necessary to configure a fast and reliable reclosing scheme. The conventional automatic reclosing scheme lacks the prediction of fault nature, and the fault nature discrimination method based on the converter injection signal is not conducive to the power transmission of the multi-terminal DC power grid. To solve the above problems, a resistor-capacitor-thyristor（RCT） snubber circuit suitable for a hybrid DC circuit breaker is proposed. The active signal injecting mode is added to realize adaptive reclosing, so as to avoid the influence of the signal generation process on the stability of power transmission in a multi-terminal DC power grid. On this basis, the attenuation effect of the current limiting reactor is deduced in detail, and the width of injecting voltage pulse is reasonably selected. Furthermore, an adaptive adjustment strategy of injecting signal amplitude based on the traveling wave protection information is proposed to improve the ability of fault nature discrimination method to withstand the transition resistance. A large number of simulation cases verify the feasibility and superiority of the proposed reclosing scheme.