Toward a Long-Life Property of the Global Optimal Solution in OPF: Numerical Studies

Abstract

This paper discovers a long-life property of the global AC optimal power flow (OPF) solution due to load variations. It is shown that the global OPF solution is always the optimal solution that remains until there is no other OPF solution. This discovery of long-life property sheds some light on OPF solutions and may lead to the development of computational methods to compute the global optimal solution in a deterministic manner. This long-life property is numerically demonstrated on two representative systems—the 9- and 118-bus systems and other test systems via the OPF feasible region approach. Numerical results show the emergence and disappearance processes of all local OPF solutions and also verify that the global optimal solution is the OPF solution with the longest lifespan. If this numerical property is well established for general OPF problems, one can explore it to develop a deterministic method for computing global OPF solution.