DISPERSED POWER SUPPLY AND COUNTER-CHARGE PREVENTIVE METHOD BY DISPERSED POWER-SUPPLY FOR LINKED COMMERCIAL FREQUENCY POWER LINE

PURPOSE:To trip a DC breaker and prevent counter discharge, by stopping an inverter circuit through an abnormality detecting signal generated from each abnormality detection circuit for an abnormality in voltage-difference, voltage, and frequency. CONSTITUTION:An output voltage from an inverter 2 and an output voltage (a voltage at a linkage point) from a dispersed power supply unit (A) are entered in a voltage-difference abnormality detecting circuit 8. A voltage abnormality detecting circuit 9 detects that the output voltage from the dispersed power- supply unit (A) becomes out of a permissible range. A frequency abnormality detecting circuit 10 detects that the output frequency from the dispersed power- supply unit (A) becomes out of a permissible range. A trip circuit 11 trips a DC breaker (S) provided at a linked point through an abnormality signal from these abnormality detecting circuits 8, 9 and 10. At the same time, an inverter 2 is stopped by an inverter stopping circuit 12 through the abnormality signal from the abnormality detecting circuits 8, 9 and 10, and counter discharge can be prevented.