OPTIMAL ISLANDS DETERMINATION IN POWER SYSTEM RESTORATION

In this paper, the effect of the islands number variation in the restoration process isinvestigated and a method to determine optimum island boundaries is presented. Also, the impactof Parallel Reactive Power Sources (PRPS) on the number and boundaries of each island andrestoration process is studied. In the optimization process, the objective function is minimizingEnergy Not Supplied (ENS) and constraints are voltage margins in buses, transmission linescapacities and generators loading limits. The ENS is evaluated based on generation capacityallocation to demand loads method. Genetic algorithm (GA) is the base of optimization and anappropriate chromosome coding is developed for the network modeling. In order to assess thecapabilities of the proposed method, the IEEE-118 bus network has been used as the test system.The results of sectionalizing the test system to 2 to 7 islands with optimum boundaries have beengiven in case studies.