A Method of Constructing Network Configuration for Outage Works by Means of Optimal Switching Power Flow

As a power system is becoming larger and more complex, it has become more difficult for planning engineers to adjust outage works since the number of maintenance works has increased accordingly. For the purpose of assisting planning engineers the authors have developed a supporting expert system for outage work planning of electric power facilities. The proposed system is aiming to maintain high supply reliability when outage works are executed based on the combined use of three different security indicies. A suitable system configuration for a particular set of outage works is chosen out of the prepared system configurations which have been formed from the past operation records. However, to obtain feasible plans from the standpoint of adequacy in system configurations, it is necessary to consider the following three issues: (a) reducing the number of switching operations, (b) transition of system configurations from day to day, and (c) complete avoidance of supply shortage at N-1 contingencies. In this paper, we propose a novel method of making up suitable system configurations by means of optimal switching power flow in DC model. In the optimal switching power flow, pivot operations on an LP like tableau is regarded to correspond to switching operations in a power system and thus it aims to obtain the optimal system configuration by minimizing some objective function. In the proposed method, the amoung of overloads in line flows is chosen as the objective function and thus a line switching is selected so that the overload reduces most. As to the consistency in transition of system configurations between the consecutive days, the tableau is augmented to include three days.