A robust active power control algorithm to maximize wind farm power tracking margins in waked conditions

Abstract. We present an active power control (APC) algorithm for wind farms that operates wind turbines to maximize their power availability in order to robustly track a reference power signal in the presence of turbulent wind lulls. The operational setpoints of the wind turbines are optimized using an engineering flow model by combining induction control with wake steering. The latter has the goal of deflecting low-momentum wakes and increasing power margins. The algorithm also features a proportional–integral closed loop inspired by the literature to correct potential errors deriving from the offline computation of the setpoints. First, we demonstrate the new approach in steady-state conditions, showing how the availability of power is increased by mitigating wake interactions. We observe that our proposed method is particularly effective in conditions of strong wake impingement, occurring in scenarios of high power demand. Next, considering two wind farm layouts, we compare the performance of the algorithm to three state-of-the-art reference APC formulations in unsteady scenarios using large-eddy simulations coupled with the actuator line method (LES-ALM). We show that the occurrence and treatment of local temporary instances of power unavailability (saturations) dramatically affect power tracking accuracy. The proposed method yields superior power tracking due to the increased power margins that limit the occurrence of saturation events. Additionally, we show that this performance is achieved with reduced structural fatigue.