| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a system interconnection protective device capable of enhancing reliability of frequency detection accuracy and capable of detecting and protecting single operation of a normal service generator under system interconnection positively and easily on the normal service generator side. <P>SOLUTION: The system interconnection protective device comprises a voltage transformer 38 for detecting the AC voltage signal of an AC power system, a circuit 30 for operating the effective value of an AC voltage signal detected by the voltage transformer 38, and a frequency detection means 41 comprising a divider 31, a filter circuit 32, a comparator 35, a counter circuit 36, and a reciprocal operating unit 37. The effective value operating circuit 30 operates a voltage effective value from an AC voltage signal detected by the voltage transformer 38 according to a predetermined formula. The divider 31 divides the AC voltage signal by a voltage effective value operated at the effective value operating circuit 30. The filter circuit 32 consists of a resistor 33 and a capacitor 34. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
