Optimal power flow based loadability assessment with detailed complementarity model for synchronous generators

The paper proposes a detailed complementarity model for synchronous generators in optimal power flow (OPF) based programs used in loadability assessment. The introduction of the complementarity model allows the optimization problem to find a critical operating point at which the generators function with constant terminal voltage when the reactive generation level is strictly within the limits or variable voltage when either the armature current limit, the overexcitation limit or the underexcitation limit is reached.