| 摘要 |
PROBLEM TO BE SOLVED: To fully protect a load from a voltage drop by cutting off a system in a short time using a forced arc-extinguishing signal outputted from a power converter, even if disconnection causes system troubles. SOLUTION: An energy storage part 6 is provided on DC side of the power converter 5 which is connected between a system power supply 1 and a load 2 via an interconnection transformer 4. In the event of power failure of the system power supply 1, a system interconnection switch 7, interconnected between the system power supply 1 and the power converter 5 and having no self arc-extinguishing capability is turned off by the forced arc-extinguishing signal outputted from the power converter 5, and off status of the system interconnection switch 7 is detected by a control circuit 15. In this distributed power supply system which allows the power converter 5 to carry out self-driving by converting the power converter 5 from a current control mode to a voltage control mode, the control circuit 15 is provided with a zero-phase-voltage generation preventing circuit which forcibly causes the polarity of prescribed phase system current to be reversed, if wrong determination makes the polarity of the system current the identical for all the three phases in the event of power failure in the system power supply 1 caused by disconnection. |
