Why do we need to use technique like ROCOF for islanding detection in distributed generation?

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Bo Jie

After you study this article (https://www.nojapower.es/expertise/2020/understanding-RCOF-protection), perhaps you can understand. Hopefully, it can help you.

Muhammned El Ibrahim

Kouider Khaled

ROCOF monitors the rate of change in the frequency of the electricity. During islanding, the mismatch between power generation and consumption within the island causes the frequency to drift. It detects this rapid change in frequency and triggers the DG unit to disconnect.

To summary, ROCOF is used for 3 principal reasons:

Ensures safety for utility workers
Maintains power quality
Prevents unexpected energization upon main power restoration