Rooted Tree Based Searching Strategies for Intentional Islanding of Distributed Generation

To achieve improvement of reliability and seamless transition between interconnected mode and islanding mode, the splitting strategy of intentional islanding of distributed generation (DG) is studied. This paper proposes rooted tree to model DG island separation according to the radial structure and service restoration process of distribution system. The level and directed properties of rooted tree are adopted to reduce the solution space from exponential to linear. Depth first search of node-weight rooted tree and edge-weight rooted tree are employed to determine island splitting strategies in the stage of planning and online-decision respectively. Simulations on the IEEE 69-bus system show that by this method, proper splitting strategies can be found quickly. This method is effective for preplanned and dynamic creation of DG intentional islanding.