Optimal Utilization of Reactive Power Capability of DFIG Based Wind Turbine by the Improved GRG Method

The doubly fed induction generator (DFIG) based wind turbine in the distribution network can not only supply active power, but also generate or absorb reactive power. In this paper, the scheme of optimally utilizing the reactive power of DFIG based wind turbines to improve the voltage level and reduce the power loss in the distribution network is proposed. First, the principle of limiting the reactive power capability of DFIG based wind turbines is analyzed. Then, the problem of optimally utilizing the reactive power of wind turbines is formulated and solved by the generalized reduced gradient (GRG) method, which is improved by the combination with augmented Lagrangian function. Finally, a real distribution network with two wind turbines in Sichuan Province, China, is chosen to conduct the numerical experiments. The results show that by the optimal utilization of the reactive power capability of wind turbines, the voltage level has obviously been improved and the power loss has been greatly reduced.