Periodic dynamic induction control of wind farms: proving the potential in simulations and wind tunnel experiments

Joeri Alexis Frederik,Robin Weber,Alessandro Croce,Jan-Willem Van Wingerden,Stefano Cacciola,Carlo Bottasso,Filippo Campagnolo

doi:10.5194/wes-5-245-2020

Abstract

Abstract. As wind turbines in a wind farm interact with each other, a control problem arises that has been extensively studied in the literature: how can we optimize the power production of a wind farm as a whole? A traditional approach to this problem is called induction control, in which the power capture of an upstream turbine is lowered for the benefit of downstream machines. In recent simulation studies, an alternative approach, where the induction factor is varied over time, has shown promising results. In this paper, the potential of this dynamic induction control (DIC) approach is further investigated. Only periodic variations, where the input is a sinusoid, are studied. A proof of concept for this periodic DIC approach will be given by the execution of scaled wind tunnel experiments, showing for the first time that this approach can yield power gains in real-world wind farms. Furthermore, the effects on the damage equivalent loads (DEL) of the turbine are evaluated in a simulation environment. These indicate that the increase in DEL on the excited turbine is limited.

Highlights

The interaction between wind turbines in a wind farm through their wake is a field of research as old as wind farms themselves
The rotor aerodynamics are modeled via blade element momentum (BEM) theory or a dynamic inflow model and may consider corrections related to hub and tip losses, tower shadow, unsteadiness, and dynamic stall, whereas lifting lines can be attached to both tower and nacelle to model the related aerodynamic loads
The effects of periodic dynamic induction control (DIC) on the power production of a three-turbine wind farm are presented for two cases, similar to onshore and offshore wind conditions

Summary

Introduction

The interaction between wind turbines in a wind farm through their wake is a field of research as old as wind farms themselves. The wake of a turbine has a wind field with a lower velocity and a higher turbulence intensity (TI), resulting in a lower power production and higher relative loads for downstream turbines To exploit this interaction between turbines, induction control (sometimes called “derating”), with induction defined as the in-wake speed deficit, has been a popular research topic in recent years. Recent simulation studies (Goit and Meyers, 2015; Munters and Meyers, 2017) have shown that so-called dynamic induction control (DIC) improves the power production in small to medium-sized wind farms This approach, where the induction factor is varied over time, generates a turbulent wind flow that enables enhanced wake recovery. This input is only constrained by different wind turbine response times τ and max-

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