Hybrid ROCOF Relay for Islanding Detection

Distributed generation (DG) is increasing in day to day life to meet the global energy consumption demand. One of the major problems with such DG is islanding. The islanding is caused in the grid connected system when a part of DG is disconnected from the main grid and continues to feed the load connected. As per the IEEE 1547 DG interconnection standards, the islanding should be detected within 2 s after islanding. This paper presents, a new rate of change of frequency (ROCOF) based hybrid islanding detection approach. It combines the passive and active ROCOF methods. The simulation results indicate this method is very efficiently classifying the islanding and non islanding events. It detects the zero power balanced islanding within 200 ms and unbalanced islanding within 100 ms. The simulation results are carried on Matlab/Simulink 2018B environment.