Network constrained optimal automatic generation control for a two area power System

In this paper a control strategy is proposed for Automatic Generation Control (AGC), which focuses on the interconnected system instead of individual areas and minimizes the cost of control while maintaining network constraints. A methodology is developed to maintain the network constraints by limiting the tie line flows within safe thermal limits when the generation and disturbances in the interconnected areas are utilized for AGC. Our contribution comes from extending the Economic AGC approach in [1] so that it is feasible for practical implementation. This is achieved by imposing constraints on a set of non physical auxiliary variables. The optimization function is extended to include the constraints on the auxiliary variables by using a logarithmic barrier function method. It is proved for a two area power system that the tie line flows attain the same values as the auxiliary variables under steady state conditions. A simulation study is presented to show the effectiveness of our approach.