ISLANDING DETECTION METHOD, CONTROLLER, ISLANDING DETECTOR, AND DISTRIBUTED POWER SUPPLY SYSTEM

摘要

PROBLEM TO BE SOLVED: To reliably detect islanding when reactive power is balanced.;SOLUTION: In the islanding detection method, reactive power for detecting whether or not a distributed power supply is disconnected from a power system and is islanded is injected into the power system. In this method, reactive power is injected into the power system when the system frequency has not substantially changed over multiple system periods in the past and the system voltage fluctuates. It is preferably determined that the system frequency has not substantially changed when the system frequency deviation has been continuously kept within a certain range over the multiple system periods in the past. It is preferably determined that the system voltage has fluctuated when the system voltage in each system period changes with a fluctuation margin specified for each system period relative to the average value of the respective system voltages of the multiple system periods in the past.;COPYRIGHT: (C)2009,JPO&INPIT