Islanding detection for a micro-grid based on the active and reactive power in the time domain

The micro-grid (MG) should supply the power to its loads continuously after disconnecting the circuit breakers between the distribution networks and the MG, which is called with islanding operation. In this case, the detection of islanding is a very important issue for the MG because the threshold values for the protection relays in the MG should be changed depending on whether the MG is connected to the grid or not. This paper proposes an islanding detection algorithm for the MG based on the active and reactive power delivered from the MG to dedicated line in the time domain. The performance of the proposed algorithm is verified under various scenarios including islanding conditions and fault conditions using the PSCAD/EMTDC simulator. The results indicate that the proposed algorithm can detect the power islanding under various islanding conditions for the different outputs of the MG, and does not mal-operate under various fault conditions varying the fault positions, irrespectively of the frequency deviation and the transient components.