Restoration of a large electric grid after a partial or complete system blackout is a difficult task complicated by many factors, including unknown cause, abnormal operating conditions, infrequently used procedures and unpredictable system configurations. Large utilities must have different scenarios and tools to deal with this problem. The coordination and overall organization of the several aspects of the restoration process will largely determine the effectiveness of the restoration and its speed of progress. The most basic determinants of this organization are the relative roles played by the operator and the computer. Thus there arises a choice between two basic organizing principles: operator dominated principle or computer dominated principle. In actual power system operation, severe restoration situations occur infrequently. Therefore, when they do occur, operators have had little first-hand, on-the job experience. Even so, they are under pressure to restore the system as quickly as possible, while paying close attention to many technical details. On other hand the great progress in both artificial intelligence software and computer hardware, increases the tendency to fully automated the restoration problem, so that the operator plays the role of an observer or supervisor.
In mathematical terms, the restoration problem may be described as a multi-objective, multi-stage, combinatorial, nonlinear, constrained optimization problem. Evolutionary Approach (EA) technique is one of the most promising artificial intelligence techniques because it is proven to be both very fast and effective when applied to a diverse set of optimization problems.
In this paper a proposed Evolutionary Approach-based methodology is used to solve the restoration problem of a large electric system with multiple generation units and transmission loops. The methodology is applied to restore a sector of Egyptian Utility after a complete blackout. The obtained results show effectiveness and validity of the proposed methodology compared to pure human experience in Egyptian National Energy Control Center.