Collaborative Transmission Network Expansion Planning for Congestion Alleviation Using Lagrangian Multipliers

This paper proposes a multi-TSO collaborative network expansion methodology of for the congestion alleviation by placing new transmission lines to different control areas in the system separately, meanwhile maintaining the security standard of the grid as a whole. Optimal power flow, using Lagrangian multipliers and locational marginal price as optimisation variables is applied. The method provides the optimal location, type, and the number of extra necessary transmission lines for the optimal network structure under the generation and load scenario that the network may encounter in the future. A test case with the New England 39 bus model is presented in this paper for the validity and effectiveness of the proposed method.