(a)
(b)
(c)
(d)
Figure 4: Structure of resonant HVDC breaker (2nd type). (a) The fault occurs. (b) The full bridge MMC submodule is triggered and an anticurrent is generated in the mechanical switch. (c) The mechanical switch is separated. The thyristor is conducted and the capacitor in the full bridge MMC submodule is charged again. (d) The FBSMs can be connected in series to change surge current.