A New DC Load Flow Method for Power System Contingency Analysis

Abstract

This paper proposes a new DC load flow method for power system contingency analysis. In recent years, more reliable operation is required to deal with complicated power systems. As a framework of security control, it is important to investigate the effect of potential faults to power systems in advance. Contingency analysis requires computational efficiency in evaluating data for controlling generating units or load flows. So far, several approaches have been developed to the contingency analysis. Among them, the DC load flow is widely used due to the computational efficiency. This paper aims at improving the computational efficiency furthermore. In particular, the indirect methods of a new approach have been applied to the process of solving a set of linear equations in the DC load flow. The conventional approaches are based on the direct method such as the LU decomposition or the Gauss elimination methods. However they have a drawback in terms of the computational time and storage. That is because fill-in elements appear in the computational process. Therefore, the indirect methods such as the CR and CGS algorithms are presented for the DC load flow of the contingency analysis. In addition, the precondition technique is introduced to the indirect methods. The proposed methods have been successfully applied to larger sample systems such as 118, 235, 352, 469 and 586 node systems.