Method for detecting unintended island formation in alternating current network, involves detecting unintended island formation based on variation of idle current at intervals and change in period length of alternating voltage

摘要

The method involves detecting the onset of unintentional islanding in response to the change in the idle current. The change of the period length (9,10) of the alternating voltage (8) is detected with one or more time measurements. The idle current is changed at intervals. The unintended island formation is detected based on the variation of the idle current at intervals and the change in the period length of the alternating voltage. An independent claim is included for a device for detecting unintended island formation in alternating current network.