Reactive power dispatch of DFIGs in wind farm based on multi‐object optimization

Abstract

Summary The reactive power (var) dispatch is realized at the system and station levels. Var dispatch to the doubly fed induction generators (DFIGs) in the wind farm is seldom studied due to the difficulty of the number and modeling accuracy of the DFIGs and dependency of the var setting on its available reactive power capability (RPC). This paper proposes an optimization model to decide the incremental var output of the DFIGs in the wind farm. The object is to minimize the increments of active power loss in the wind farm and the deviation of the stator voltage of the DFIGs. Considering the voltage fluctuation at the PCC, the distribution coefficient of the var increment is defined for the DFIGs. The nonlinear constraints are expressed by the first + second‐order sensitivities of the active power loss of the wind farm and the stator voltages of the DFIGs to the var output of the DFIGs. The nondominated sorting genetic algorithm II (NSGA‐II) is applied to obtain the Pareto front, with the evaluation indicators of the var margin defined to decide the incremental var output of the DFIGs. The numerical results validate the feasibility of the proposed algorithm. The reactive power demand to the wind farm is distributed among the DFIGs satisfying the objects and the constraints with desirable accuracy and calculation efficiency.