Evaluation of interconnected power systems controlled islanding

Controlled separation of power systems is the last defense line against wide-area blackout. As a special protection scheme, the methodology of system splitting is a comprehensive decision making problem. This paper introduces a novel approach for separation of the integrated power systems into several stable islands. The proposed method combines both the dynamic and static characteristics of interconnected power networks and determines the proper splitting schemes. The presented algorithm searches for proper islanding strategies using the Krylov projection method and a new optimization algorithm to find the proper splitting points such that the total load shedding is minimized. The method reduces the huge initial search space of islanding strategies considering dynamic characteristics of integrated power systems. The method limits search space to only the boundary networks of coherent machines. A spanning tree based breadth first search algorithm is used to find all possible combination of stable islands. The speed of the proposed algorithm is remarkably high and it can be used for real-time splitting of the power systems. The algorithm is applied to IEEE118 bus test system. Results show the effectiveness and capability of the method to determine the fast and accurate proper islanding strategies. The stability of the islands is verified by time domain simulation.