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Friday, 20 November 2015
12:00 - 13:30 Breakthrough session
Breakthrough sessions  
Onshore      Offshore    


Room: Belleville

A thorough review of abstracts cannot be done overnight – hence the main call for abstracts having closed in May. This is fine in most cases but, as delegates have told us, it is too early to be able to propose the very latest findings. Hence, we hold a call for ‘breakthrough abstracts’ presenting work that is genuinely ground-breaking and has in that form never been made public before. We introduced this at EWEA OFFSHORE 2015 and given the positive outcome, we decided to repeat this at EWEA 2015.

This call for ‘breakthrough abstracts’ took place from 1-14 September 2015. We would like to thank all the submitters forward to a highly interesting breakthrough session at EWEA 2015!

This breakthrough session covers topics from the resource to power performance, from turbines to wind farms and combines measurements and models. In a mixture of scientific and technical presentations attendees will learn about the experience and increasing acceptance of floating lidar technologies, covered by international IEA Wind experts. Turbulence remains of course a challenge for lidar measurements as well as for simplified but manageable models. A talk on turbulence intensities in large offshore wind farms will shine some light on the performance of models if compared with real measurements. The combination of turbulent fluctuations and large rotor blades leads to non-trivial blade deflections and modern control methods try to cope with this. However in order to be successful, the current deflection needs to be known and session attendees will see a new measurement concept that promises do this and which has just been tested on a large turbine this August. Finally combining this knowledge of turbulent flows with aero-elastic turbine models will be used to predict power performances in non-standard conditions.
 

Learning objectives

After attending this session, delegates will be able to:

  • estimate the current possibilities of using floating lidars in offshore wind farms.
  • quantify the performance of commonly used turbulence intensity models in real life.
  • explain how blade deflection of large blades in turbulent flows can be tackled.
  • evaluate the potential of using large wind farm data sets and modern computer power.
Lead Session Chair:
Stephan Barth, ForWind - Center for Wind Energy Research, Germany

Co-chair(s):
Tim Robinson, EWEA - The European Wind Energy Association asbl/vzw, Belgium
Peter Baek LM Wind Power, Denmark
Co-authors:
Peter Baek (1) F Claus Byskov (1)
(1) LM Wind Power, Kolding, Denmark

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Presenter's biography

Biographies are supplied directly by presenters at EWEA 2015 and are published here unedited

Peter has an industrial PhD degree from the Technical University of Denmark and LM Wind Power in advanced load control of wind turbines using active aerodynamic devices. Peter currently works with conceptual design of blades optimizing turbine performance over turbine costs. Furthermore Peter is involved in the development of new sensor technology for blades.

Abstract

Want to know the blade deflection 50 times per second?

Introduction

The growth of wind farm development in low wind speed regions is driving up rotor diameters. Blade designs become increasingly deflection driven, and the safe tip to tower clearance under all wind conditions contradicts goals of minimizing blade mass. The newest wind turbine control methods seek to control blade deflection, but realizing the full potential of such measures requires high speed sampled information about blade deflection. Now a consortium of companies and academics, led by LM Wind Power, has developed a technology to do exactly that. Full scale validation commenced in August 2015 at the National Test Center for Wind Turbines in Østerild, Denmark.

Approach

Traditional approaches to estimation of blade deflection have been based on strain measurements on blades and other main components. All of these, however, are subject to calibration and accuracy of models specifying how to transform the strain measured to blade deflection. A new approach takes advantage of recent development in radio frequency based technology for distance measurement. Radio techniques and technologies, well known for reliability and accuracy in other industrial applications, have been successfully implemented in modern LM Wind Power blades. The new technology delivers accurate measurements in meters which is directly comparable to the known blade geometry.

Main body of abstract

A fundamental issue to address when implementing any kind of electronics in the outer half of a wind turbine blade is to make the installation withstand the harsh environment prone to lightning strikes. The dilemma is how to have a measurement point near the blade tip, but no powered electronic devices in the area. The LM Wind Power led consortium has solved this dilemma in new ways and with several patents pending.

The innovation has been developed by a diverse team of experts representing different fields of research. It combines technologies and solutions to form a blade deflection sensor system that complies with existing blade manufacturing processes and practices for keeping a low lost production factor once the blades are spinning on the turbine.

A full scale prototype of this new technology has been implemented on a set of LM 58.7 blades which have been in operation on a turbine at Østerild, Denmark since August 2015. Prior to this, one of the blades successfully passed a high voltage leader attachment test. A static pull of another blade in the set proved that the tip position could be measured with precision very close to measurements conducted in parallel using laser range equipment.

At the time of writing this abstract, real time data is being recorded from the blades operating at Østerild. They are carefully analyzed and the system will continue be further optimized. It is safe to say that the presentation at the ‘Breakthrough’ conference session will be truly at the cutting edge of measuring deflection on wind turbine blades in full operation.


Conclusion

Four years ago, LM Wind Power formed a highly cross-functional consortium with other wind energy sub suppliers and an academic research institution. The purpose was to develop a piece of next generation technology that no sub supplier would have had the capabilities to develop on its own. The idea was promising enough to receive considerable financial support from Innovation Fund Denmark, and now the consortium has successfully delivered technology that has gone all the way to full scale testing.


Learning objectives
The delegates will learn that integration of radio based sensor technology in wind turbine blades is indeed possible without disregarding normal practices. Furthermore, the presentation will show what types of measurements this type of sensor can deliver in real time and the expected application of the sensor.