Lagrangian decomposition approach to active power congestion management across interconnected regions

In the paper an augmented Lagrangian relaxation based algorithm for regional decomposition optimal power flow (OPF) is presented to address congestion management across interconnected regions. An OPF problem is decomposed into regional sub-problems through Lagrangian relaxation. Unlike other existing methods, no dummy generators or loads are added into the original network model. Applying this algorithm with the real-time balancing mechanism, the problem of active power congestion management across interconnected regions is separated into quadratic regional sub-problems, which can be solved either sequentially or in parallel. With this approach, regional ISOs can relieve network congestion co-ordinately without knowing any other regions´ network information but the corresponding Lagrangian multipliers of coupling constraints between regions. The IEEE RTS-96 with three interconnected regions is studied to illustrate the proposed approach