| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an islanding operation detector which can realize high-speed injection of reactive power suitable for high-speed detection of islanding operation of a distributed power supply. <P>SOLUTION: An islanding operation detector 5, comprising an inverter circuit 11 for injecting reactive power between a distributed power supply 2 and a commercial system 3, and an islanding operation detection circuit 14 for detecting islanding operation of a distributed power supply, based on the frequency variation of injected reactive power, is further provided with a section 21 for measuring the system period of the commercial system by 5 ms units; a section 22 for sequentially detecting the moving average value of the system period for 40 ms, based on the system period measured sequentially by 5 ms units; a section 23 for sequentially storing the moving average value; a section 24 for calculating deviation of a newest running mean value under storage from a past moving average value 200 ms prior for each system period by 5 ms units; and a section 28 for operating the reactive energy of reactive power injected by the inverter circuit. <P>COPYRIGHT: (C)2008,JPO&INPIT |
