# Numerical and Experimental Methods for the Assessment of Wind Turbine Control Upgrades

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## Abstract

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## 1. Introduction

- Employing operational data to provide an estimate of the impact of the upgrade after some months of operation;
- validating a purely numerical framework (based on aeroelastic simulations of the wind turbine of interest) for estimating the impact of the control optimization.

## 2. The Test Case

## 3. Operational Data Analysis: Methods and Results

- ${D}_{bef}$ goes from 1 September 2017 to 1 March 2018. It is a period during which the standard rotor rpm–power curve was operating.
- ${D}_{aft}$ goes from 1 March 2018 to 1 July 2018. It is a period during which T7 was operating with the improved rotor rpm–power curve.

- The nacelle wind speed,
- the power output,
- the individual blade pitch angles,
- the rotor revolutions per minute,
- the generator revolutions per minute,
- the high speed rotor temperature.

- The power of T6;
- the power of T9;
- the rotor rpm of T8.

- ${D}_{bef}$ is randomly divided in two subsets: D0 ($\frac{2}{3}$ of the data) and D1 ($\frac{1}{3}$ of the data). D0 is used for training the model and constructing the weight matrix $\mathit{W}$, and D1 is used for the pre-upgrade data set employed for validating the model.
- ${D}_{aft}$ is the post-upgrade data set employed for validating the model. For notation consistency, it is also referred to equivalently as D2.

## 4. Numerical Analysis: Methods and Results

## 5. Conclusions

## Author Contributions

## Funding

## Conflicts of Interest

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**Figure 3.**The average difference between measurements and simulation (Equation (1)) of the power of T7, for data sets D1 and D2 and for a sample run of the model.

**Figure 5.**Example of simulated wind, electric power, and rotor rpm time history from FAST (fatigue, aerodynamics, structures, and turbulence).

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**MDPI and ACS Style**

Astolfi, D.; Castellani, F.; Berno, F.; Terzi, L.
Numerical and Experimental Methods for the Assessment of Wind Turbine Control Upgrades. *Appl. Sci.* **2018**, *8*, 2639.
https://doi.org/10.3390/app8122639

**AMA Style**

Astolfi D, Castellani F, Berno F, Terzi L.
Numerical and Experimental Methods for the Assessment of Wind Turbine Control Upgrades. *Applied Sciences*. 2018; 8(12):2639.
https://doi.org/10.3390/app8122639

**Chicago/Turabian Style**

Astolfi, Davide, Francesco Castellani, Francesco Berno, and Ludovico Terzi.
2018. "Numerical and Experimental Methods for the Assessment of Wind Turbine Control Upgrades" *Applied Sciences* 8, no. 12: 2639.
https://doi.org/10.3390/app8122639