A Combinatorial Algorithm for Large-Scale Power System Islanding

Intentional Controlled Islanding (ICI) is an online measure employed to prevent cascaded system outage after a disturbance in the power system. By switching off select lines, the system operator can create smaller, easier to control islands. An algorithm for ICI should be fast to implement in real time, as well as capable of integrating islanding requirements such as coherency of the generators in an island and minimum disruption of the power balance caused by the switching of lines. In this work, we approximate the solution to a common ICI formulation by employing a combinatorial approximation scheme of the normalized cut. This approach is easily implementable and numerically robust, exhibits high computational efficiency and allows for a natural integration of islanding requirements (such as generator minimum load and inflexible lines) into the problem solution. Experimental results on systems with up to 3000 buses verify the effectiveness of our approach.