Combined quadratic-separable programming OPF algorithm for economic dispatch and security control

This paper presents a new algorithm for optimal power flow (OPF), which is based on P/Q decomposition of OPF problem and on combined application of quadratic and separable programming methods. Initially the unit cost curves are approximated by the quadratic functions and the quadratic programming algorithm is applied as a starting method. This gives a good initial point for optimization and reduces the total computation time. The modification of a separable programming (SP) algorithm with generation of approximating intervals is considered. A new quadratic-separable algorithm for OPF is proposed, which combines the main advantages of quadratic and separable programming methods. A bi-criterion formulation of security control problem on the base of economic and security objective functions (OF) is proposed. The numerical results of OPF for large-scale power systems are given for different methods.