Large-scale OPF based on voltage grading and network partition

In this paper, a model of a large-scale optimal power flow (OPF) under voltage grading and network partition and its algorithm is presented. Based on the principles of open loop operations, the node injecting current method is used to divide the large-scale power grid into voltage grading and district dividing structures. The power network is further divided into a high-voltage main network and several subnets according to voltage levels of 220 kV. The subnets are connected by means of boundary nodes, and the partition model is solved using the improved approximate Newton direction method, which achieves complete dynamic decoupling simply by exchanging boundary variables between the main network and the subnets. A largescale power grid thus is decomposed into many subnets, making the solution of the problem simpler and faster while helping to protect the information of individual subnets. The system is tested for correctness and effectiveness of the proposed model, and the results obtained are matched in real-time. Finally, the algorithm is seen to have good convergence while improving calculation speed.