A converter cell includes first and second arms, each of which includes a semiconductor switching element and a diode, and a short circuit part connected in parallel to the second arm, and when a DC fault detection unit detects occurrence of a DC fault, a control circuit outputs, to the converter cell, a fault handling command for setting the short circuit part to a conductive state, setting the semiconductor switching element to a conductive state, and setting the semiconductor switching element to a non-conductive state, to thereby set both the semiconductor switching element and the diode to conductive states in the second arm.