| 摘要 |
A protection relay outputs a current capable of determining a fault and removes a fault point, without stopping a power converter during a DC short-circuit fault. The present invention is provided with: a power converter (1) in which a contact point of a positive side arm and a negative side arm for each phase is connected to the AC line of each phase, one end of the positive side arm and the negative side arm of each phase is connected to a DC line, and power is converted between AC and DC; and a control device (100) for controlling said power converter. The positive side arm and the negative side arm are configured by connecting in a series one or a plurality of series bodies having a plurality of switching elements connected to each other in a series and converter cells (10) formed from a DC capacitor connected in parallel with said series bodies. The control device outputs an AC voltage, which is the same as that during a steady state, to an AC end of the power converter during a DC short-circuit fault and is provided with a DC voltage command value calculating unit (140) for calculating a voltage command value for outputting to a DC end of the power converter a DC voltage that is capable of operating the protective relay inside the DC line. |
