| 摘要 |
PURPOSE:To separate a receiving-point breaker quickly without an expensive transfer breaking device by providing a higher-harmonic power supply in each in-plant and always monitoring the higher-harmonic impedance on the system side in a system interconnection system, wherein a plurality of non-utility generating devices are interconnected to a utility system and there is reverse current. CONSTITUTION:Harmonic-wave generators 17a and 17b, which inject the higher harmonic waves that are synchronized with the voltage of the system and have the equal phase, frequency and voltage, respectively into a point A and a point B, are provided for the system buses of the in-plant in non-utility generating devices 1a and 1b. Furthermore, current transformers 19a and 19b, which detect the higher-harmonic current on the receiving side, and impedance detecting circuits 18a and 18b, which operate the impedance of the receiving side based on the outputs of the current transformers 19a and 19b, are provided. The service interruption on the system side is detected based on the impedance change obtained from the impedance detecting circuits 18a and 18b. Thus, a transfer breaking device can be omitted between a receiving-line sending breaker 5 and receiving-point breakers 14a and 14b in the demand house for the non- utility generating device. |
