Islanding cutset searching approach based on dispatching area

Based on dispatching area, a new power system islanding cutset searching approach is proposed in the paper. The buses of a system are put in a set of dispatching subareas. Load buses are outer layer buses of the subareas, and generators in one subarea are considered to be coherent. When the generators in some subareas are out-of-step to other generators, the subareas are defined as out-of-step areas (OOSA); the other part of the system is called remaining system. If the load- generation imbalance of the OOSA does not meet power balance requirements, some load buses are transferred between OOSA boundary and the remaining system until the requirements are met. The transmission lines connecting the OOSA and the remaining system form islanding cutsets. The approach reduces bus searching space from all system buses to OOSA boundary buses, which reduces calculation complexity significantly. Simulation results of the IEEE 30-bus system demonstrate its effectiveness.