Reactive Power Optimization Model for Voltage Constraint Margin

Objective function of a traditional reactive power optimization method is usually expressed as that minimizing the active transmission power loss under rigid voltage constrains,but neglects the soft characteristics of voltage constrains.It can make the voltage of some bus close to its boundary,thus becoming potential trouble of system security.To solve this problem the reactive power optimization model based on fuzzy theory is carried out.The model with fuzzy operating security constrains applies nonlinear primal-dual interior-point method.The simulation result of test system shows that the proposed model can reduce the decrement of transmission losses and greatly extent security margin of voltage.