A power converter, which is configured to interconnect an AC system and a DC system to transfer electric power, the power converter comprising: - a plurality of converter cells connected in series to one another; - a DC fault detection unit configured to detect a fault that has occurred in the DC system; and - a control circuit configured to control each of the plurality of converter cells, wherein each of the plurality of converter cells includes: - a first arm, which includes a first semiconductor switching element having a reverse conduction characteristic and a first diode connected in anti-parallel with the first semiconductor switching element; - a second arm, which is connected in series to the first arm, and includes a second semiconductor switching element having a reverse conduction characteristic and a second diode connected in anti-parallel with the second semiconductor switching element; - output terminals (TP, TN) connected to both ends of the second arm; and - a short circuit part formed of a mechanical switch and connected in parallel to the second arm, wherein the semiconductor switching element is a MOSFET, wherein the control circuit is configured to output, when the DC fault detection unit detects the occurrence of the fault, a fault handling command to each of the plurality of converter cells, and wherein the fault handling command is configured to set the first semiconductor switching element to a non-conductive state, set the second semiconductor switching element to a conductive state to flow a short-circuit current through the converter cell splitting to the second diode and the second semiconductor switching element, and set the short circuit part to a conductive state, wherein, in response to the fault handling command output by the control circuit, response time until the second semiconductor switching element is set to the conductive state is configured to be longer than response time until the first semiconductor switching element is set to the non-conductive state. - a plurality of converter cells connected in series to one another; - a DC fault detection unit configured to detect a fault that has occurred in the DC system; and - a control circuit configured to control each of the plurality of converter cells, wherein each of the plurality of converter cells includes: - a first arm, which includes a first semiconductor switching element having a reverse conduction characteristic and a first diode connected in anti-parallel with the first semiconductor switching element; - a second arm, which is connected in series to the first arm, and includes a second semiconductor switching element having a reverse conduction characteristic and a second diode connected in anti-parallel with the second semiconductor switching element; - output terminals (TP, TN) connected to both ends of the second arm; and - a short circuit part formed of a mechanical switch and connected in parallel to the second arm, - a first arm, which includes a first semiconductor switching element having a reverse conduction characteristic and a first diode connected in anti-parallel with the first semiconductor switching element; - a second arm, which is connected in series to the first arm, and includes a second semiconductor switching element having a reverse conduction characteristic and a second diode connected in anti-parallel with the second semiconductor switching element; - output terminals (TP, TN) connected to both ends of the second arm; and - a short circuit part formed of a mechanical switch and connected in parallel to the second arm, wherein the semiconductor switching element is a MOSFET, wherein the control circuit is configured to output, when the DC fault detection unit detects the occurrence of the fault, a fault handling command to each of the plurality of converter cells, and wherein the fault handling command is configured to set the first semiconductor switching element to a non-conductive state, set the second semiconductor switching element to a conductive state to flow a short-circuit current through the converter cell splitting to the second diode and the second semiconductor switching element, and set the short circuit part to a conductive state, wherein, in response to the fault handling command output by the control circuit, response time until the second semiconductor switching element is set to the conductive state is configured to be longer than response time until the first semiconductor switching element is set to the non-conductive state.