A quadratic robust optimization model for automatic voltage control on wind farm side

Connecting high penetration of wind power into power grid usually makes voltage fluctuate, due to the volatile nature of wind power injection. This paper therefore proposes a quadratic robust optimization model to guarantee the voltage of each wind unit within the security region, no matter how the wind power varies. Based on the wind power prediction, the prediction error is regarded as uncertainties, and the robust solution can be found by regulating the reactive power equipment and each wind unit using the duality filter method. In the proposed model, linearized derivation instead of original non-linear expressions in the objective function and constraints has been utilized. Furthermore, inner loop iterative method is introduced to reduce the linearized error, which divides the optimal voltage control into multiple steps with piecewise values and updates the sensitivity at each step, according to different wind farm size and condition. A test system with 36 wind units has been simulated, and the result using Monte Carlo simulation. Comparison with traditional method shows the effectiveness of proposed method.