Contributions to wind farm power estimation considering wind direction‐dependent wake effects

Abstract

This paper presents a contribution to wind farm ouput power estimation. The calculation for a single wind turbine involves the use of the power coefficient or, more directly, the power curve data sheet. Thus, if the wind speed value is given, a simple calculation or search in the data sheet will provide the generated power as a result. However, a wind farm generally comprises more than one wind turbine, which means the estimation of power generated by the wind farm as a function of the wind speed is a more complex process that depends on several factors, including the important issue of wind direction. While the concept of a wind turbine power curve for a single wind turbine is clear, it is more subject to discussion when applied to a whole wind farm. This paper provides a simplified method for the estimation of wind farm power, based on the use of an equivalent wake effect coefficient.

Integrated Wind Farm Power Curve and Power Curve Distribution Function Considering the Wake Effect and Terrain Gradient

“…It is based on the previous work by Shi et al [21] which is based on the Jensen's wake model [26,27]. The WT power curve is represented by the continuous logistic function [22][23][24][25]. The Monte Carlo simulations are presented to justify the accuracy of the proposed model.…”

“…The main improvement and novelty of this study with respect to other works of the same authors is that it includes a much better approach to complex terrain analysis. In previous works [23][24][25] plain terrains were assumed, which can be used in a wide set of cases, but not always. Therefore, this study is considered to be a much more complete work.…”

“…(iii) Wind from all directions was not taken into account in this model. Since the level of symmetry assumed is not always consistent with the real scenario, it should be combined with the contribution proposed in [25] and a more accurate model developed accordingly. (iv) A more accurate wake model could be used, instead of Jensen's wake model, for obtaining the WF power curve such as the Gaussian wake model proposed in [2].…”

“…Moreover, the wake deficit of the whole WF is synthesized to be represented by one wake coefficient which avoids the computational complexity of calculating the wake deficit one by one. In addition, in [25], four major wind directions were taken into account for the approximation of the WF output power calculation which further refined this model.…”

“…As is pointed out in [23][24][25], it is advantageous to utilize these models in view of their simplicity as compared with other proposals and to preserve accuracy. In addition, wake effects are already synthesized in the expression of total power and WF power PDF.…”