Multilevel approach to optimal interconnected power system dispatch

The optimal power flow problem with tieline security constraints is formulated as a two-level optimization scheme for interconnected power systems. In contrast with other approximate methods, the exact overall power system equations are decomposed into first-level subsystems which correspond to individual company networks. The particular decomposition developed in this paper readily lends itself to the imposition of tieline security constraints by the second-level coordinator. Conditions for the optimal coordination of subsystems are formulated to require a minimal amount of data interchange. An efficient second-level coordination algorithm is developed to achieve the exact overall optimal power flow solution in a few iterations. This is illustrated by a few sample problems for a fully interconnected three subsystem network.