Novel Approach for Secure Islanding Detection in Synchronous Generator Based Microgrids

In this paper, a novel islanding detection approach is proposed for microgrids (mu Gs) including small scale synchronous generators (SSSGs). Derivative of the equivalent resistance seen from the SSSG terminal with respect to the angular frequency is exploited as the islanding detection index. Under the gridconnected operation condition, a non-islanding event results in a large value of the index. However, during the mu G islanding events and under mu G islanded operation conditions, the index is zero for constant impedance loads and has a small value considering the voltage/frequency dependence of the loads. Thus, the introduced index can properly discriminate the islanding events from other system disturbances. The setting parameters used in the proposed approach are easy to obtain using the presented analytical studies. Performance of the proposed approach is evaluated using extensive simulation studies in the PSCAD/EMTDC software. The obtained results reveal more security and reliability of the proposed approach in comparison with those of the existing islanding detection methods.