Modified Equivalent Network Approximation Based Distributed Optimal Power Flow for Bulk Transmission Grid

Power system optimization problems are solved in a centralized manner with approximations or relaxations in power flow equations. However, applying the centralized algorithm for power system optimization has become challenging with expanding multi-area interconnected power systems. Existing literature shows that equivalent network approximations (ENA) can be a good solution for distributed optimization. However, despite being proven in distribution systems, applying ENA in transmission systems is very difficult because of its mesh nature. In this article, we propose a Sequential Quadratic Programming (SQP) based distributed optimal power flow (D-OPF) method for bulk power transmission grid with a modified ENA framework (MENA). The method is validated with IEEE 14 bus and IEEE 118 bus transmission networks. The approach is found to outperform the existing Alternating Direction Method of Multipliers (ADMM), Auxiliary Problem Principal (APP), and Optimality Condition Decomposition with Correction (OCDC) algorithm.