Comparison of loads for wind turbine down-regulation strategies

Abstract

Abstract-For wind farm active power setpoint tracking, both farm level and turbine level down-regulation strategies should to be optimized considering turbine health condition. Several down-regulation strategies are chosen to analyse the wind turbine load performance according to different wind speed and power reference. In this paper we suggest appropriate down-regulation strategy to control wind turbine for active power reference tracking. we compare four different down-regulation strategies, namely Const-Ω, Const-λ , Max-Ω and Min-C t and discuss the loads on main components and downstream wind speed by presenting analysis of several wind scenarios and simulation in full-range operation.

On Wind Turbine Power Delta Control

“…Other authors have proposed a simple extension to the modified MPPT curve, to achieve proportional delta control via a combination of generator speed and blade pitch angle modifications [14]. This allows precise control of the tip-speed ratio λ and the blade pitch angle β at different de-rating command values, which is relevant to turbine dynamics and loads [14][15][16][17]. Its implementation is rather simple, as shown by Figures 1 and 2, where the two black 1D look-up tables are sufficient.…”

“…Zhu et al [17] proposed a different, load-based delta control optimization at the farm level. This required the farm controller to set the turbine-level power setpoint based on wind speed.…”

“…4: From λ n , P δ and ω n , calculate β δ via (46). 5: From U, λ n and ω n , calculate Q e for β = β δ via (17).…”

Evaluation of different power tracking operating strategies considering turbine loading and power dynamics

“…(1), it is apparent that a variation in the power output according to the demand can be achieved by an adjustment of the rotational speed, the generator torque, or both. Consequently, there is a need to study the implications of different operating strategies for power tracking as discussed in Deshpande and Peters (2012), Aho et al (2013Aho et al ( , 2016, Jeong et al (2014), Mirzaei et al (2014), Zhu et al (2017), andLio et al (2018). All of the works address the nonunique distribution of possible operating points on the power conversion surface, where different objectives like constant rotational speed (Aho et al, 2013;Jeong et al, 2014;Mirzaei et al, 2014;Zhu et al, 2017;Lio et al, 2018), the constant tip speed ratio (Mirzaei et al, 2014;Zhu et al, 2017;Lio et al, 2018), or the minimum thrust coefficient (Zhu et al, 2017;Lio et al, 2018) may determine the operating trajectories enforced by the controller.…”

“…Consequently, there is a need to study the implications of different operating strategies for power tracking as discussed in Deshpande and Peters (2012), Aho et al (2013Aho et al ( , 2016, Jeong et al (2014), Mirzaei et al (2014), Zhu et al (2017), andLio et al (2018). All of the works address the nonunique distribution of possible operating points on the power conversion surface, where different objectives like constant rotational speed (Aho et al, 2013;Jeong et al, 2014;Mirzaei et al, 2014;Zhu et al, 2017;Lio et al, 2018), the constant tip speed ratio (Mirzaei et al, 2014;Zhu et al, 2017;Lio et al, 2018), or the minimum thrust coefficient (Zhu et al, 2017;Lio et al, 2018) may determine the operating trajectories enforced by the controller. Most of the works apply augmented versions of commonly used control loops to enable the power tracking functionality by varying the set points of the applied controller (Deshpande and Peters, 2012;Aho et al, 2013Aho et al, , 2016Jeong et al, 2014;Zhu et al, 2017;Lio et al, 2018).…”