08 LIDAR SUPPLEMENT Samuel Davoust


Scientific Product Manager at Avent Lidar Technology


Benefits of nacelle-mounted Lidar for wind turbine power performance analysis and optimisation


The wind industry is striving to develop new technologies to improve the economic performance and reliability of wind turbines and wind farms. The Lidar (Light Detection and Ranging) technology, mounted on wind turbine nacelles to measure the wind upstream of the turbine, is a promising new and cost effective tool to reduce uncertainties on annual energy production, reduce O&M costs and optimise power performance.


Designed from operational experience, the Wind Iris by Avent Lidar Technology is a robust and easy to deploy performance analysis instrument. Safely installed on the nacelle, this two-beam pulsed Lidar measures the horizontal wind speed and direction at hub-height and at 10 distances from 40m to 400m upwind of the turbine, simultaneously measured with an acquisition frequency up to 10Hz. The precision of the instrument, its reliability and its ability to measure power curves identical to those obtained with a met mast following the IEC 61400-12-1 standard have been proven on the field by industry experts1,2


. With an installation lasting no more


than half a day, the cost of using this equipment is drastically lower compared to a met mast, especially offshore. Once installed, power curves


are obtained faster because of the permanent alignment of measurements upwind, and because less wind sectors need to be excluded. These benefits can readily be used for several


applications. First, more power curve measurements can be performed during wind farm commissioning which by reducing uncertainties, reduces the cost of wind farm projects. Once the wind farm is in operation, the Wind Iris can be moved from turbine to turbine in order to monitor performances, leading to faster decisions for maintenance operations. Beyond performance monitoring, the Wind Iris is a wind turbine optimisation tool which can be used to correct yaw errors and to adjust other turbine parameters. On a wind farm’s scale, wind sector management can be optimised by measuring wind


Lidar comparison against cup anemometer (top) and power curve obtained with the Wind Iris (bottom) at Risø’s Høvsøre test site1


speed deficit and turbulence intensity perceived by each turbine as result of nearby wakes. This leads to new strategies for global power optimisation and exclusions of wind sectors. In a later stage, retrofitting turbines with


Lidar-assisted control using this technology will bring adaptive solutions for under-performing wind farms in difficult sites, until a new generation of wind turbines integrating Lidar as a core component will emerge.


References


1. Power Performance Measured Using a Nacelle Lidar. Wagner, R. et al. 2011.


2. First Test of a Nacelle-based 2-beam Wind Lidar System under Offshore Conditions. Cañadillas, B. and Neuman, T. 2011.


Nacelle mounted two-beam Lidar setup


International Sustainable Energy Review Volume 5, Issue 3, 2011


Samuel Davoust, PhD in fluid mechanics, is scientific product manager at Avent Lidar Technology, a joint investment of Leosphere and NRG Systems dedicated to nacelle-mounted Lidars.


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