This paper analyzes critical cases of the optimal power flow (OPF) problem, for which the OPF algorithms usually fail to find a solution. The analysis is based on a parameterized OPF model and on its optimality conditions, which are firstly derived considering the original OPF formulation, with equality and inequality constraints, and subsequently extended to the formulation adopted by the primal-dual interior point methods. An equivalent of the Brazilian Southern Region system is used to illustrate the critical cases.
Optimal Power Flow; Newton Method; Interior Point Method; Infeasibility; Multiple Solutions
