An Application of Tabu Search to Problem of Constructing Network Configuration for Outage Works Considering N-1 security

Abstract

The authors have so far proposed an approach for generating system configurations based on the optimal switching power flow (OSPF) algorithm proposed by H. Glavitch. The proposed approach takes account of day to day outage works continuity by augmenting the tableau to consecutive three days. The ratio of the power flow of a line to its nominal capacity (referred to as iload ratioi) is chosen as an objective function in the pivot operations. However, since the proposed approach minimizes the objective function with respect to a line with the maximum ratio, it is impossible to completely avoid from causing overload at N-1 contingencies. The main contribution of this paper is to present an efficient method for generating system configurations that meet the security constraint for N-1 contingencies. We adopt the sum of two different functions for pivot operations: maximum load ratio under normal conditions and N-1 contingencies. Owing to the adopted composite functions and the fundamental characteristic of OSPF, the amount of computation for searching an optimal system configuration in consideration of N-1 security can be reduced significantly. In addition, we propose a new method for selecting pivot operations based on the tabu search so as to prevent a solution from falling into a local optimum. In order to confirm the effectiveness of the proposed method, a part of the 110kV transmission systems of the Chugoku Electric Power Company is chosen as a test system. Results obtained have shown the clear advantages of the proposed method in both the reduction of switching operations and the sustenance of N-1 security.