A Scheduled Intentional Islanding Method Based on Ranking of Possible Islanding Zone

Abstract

In this article, a new ranking based approach is adopted that can rank different islanding zones (IZs) based upon their stability indices during any major disturbances incepted inside the microgrid. A ranking index, known as Ranking of Islanded Zone (ROIZ), is formulated for all possible IZs inside the microgrid which indicates the stability of each zone. If the values of ROIZ are positive, then the IZs are stable and on the other hand negative values of ROIZ lead towards the unstable IZs within the microgrid. The index is formulated by considering the critical levels of the connected loads, stability of bus voltage, frequency as well as line flow inside the IZ. The stability check of the proposed ranking approach is achieved by the small-signal analysis of microgrid, where the traces of eigenvalues of the IZ state-space matrix is evaluated. The performance of the technique is also tested with the coherent and non-coherent group distributed energy resources (DERs) available inside the IZs. To validate the performance of the proposed scheme, two test systems (a 7-bus and IEEE-33 bus test system) are simulated in the Real-Time Digital Simulation (RTDS) platform and the proposed scheme is tested.