Application of Distributed Optimal Power Flow to Power System Security Assessment

This paper presents an algorithm for the parallel solution of the security constrained optimal power flow (SCOPF) problem in a decentralized framework, consisting of regions, using a price-based mechanism that models each region as an economic unit. We first solve the distributed optimal power flow (OPF) problem to determine the maximum secure simultaneous transfer capability of each tie-line between adjacent regions by taking into account only the security constraints imposed on the tie-lines. In this article, the line outage distribution factors (LODF) calculated at the current state are used to formulate the appended constraints. Once the secure transfer capability of each tie-line is determined, the intraregional SCOPF is performed using the conventional linear programming (LP) approach. A description of the inclusion of security constraints with the distributed optimal power flow algorithm will be given, followed by the case studies for Korea Electric Power System.