Posters

Abstract

Along with several other requirements, IEC 61400-12-1 stipulates that 180 hours of measurement should be applied towards WTG power curve validation. It is noteworthy that the standard also requires a minimum sample of 3 data points per wind bin and assumes that each data point is a 10min average commonly supplied by WTG SCADA systems for decades. It follows that the total amount of data-points required according to the standard in order to validate a power curve is 1,080 (180*6). Windborne is a patented, drone deployed payload able to accurately measure wind speed, direction, 3D vectors, temperature and pressure. It is comms and energy independent and processes the data on board. It is best thought of as a flying wind mast, positioned on demand anywhere within a wind farm. This enables it to always measure up-wind, in non-waked sectors, at hub height or other heights and at specific distances from a given WTG. The sensor and system were validated in a 4-week long field test by Deutsche WindGuard demonstrating best in class results for wind direction (R² = 1.000) and wind speed (R² = 0.9998). The sensor is Measnet certified following its calibration in the Deutsche WindGuard wind tunnels. Indeed Windborne has been commercially testing WTGs for underperformance for over 18 months across Europe and the USA. As one representative example, between September and December 2023, Windborne has performance tested 80 turbines at a single wind farm in Texas. About 20-30x more that stationary instruments would expectedly achieve. However, do mobility, scalability and flexibility come at a price? the duration of a test per WTG using Windborne is usually about 3 days or a net of 18 hours given that batteries need to be changed periodically. How then are the required 1,080 data points obtained? Most operators are currently able to extract high resolution SCADA data through OPC servers - usually of 1 sec or 10 sec resolutions. This data is recorded for each tested turbine during the campaign and aggregated into 1 minute data-points both from SCADA and from Windborne whose granular measurement rate is 5Hz. The required 1,080 data-points are obtained (18*60). Incidentally many more than 3 samples per bin become available as well. However, the ultimate objective is the recovery of lost MWh, and detection of underperformance through remote sensing is the first step on that journey. Economics is the first gap to bridge, and as far as wind farms in operation are concerned, both masts and LiDARs have failed to penetrate the OPEX market considerably due to their limited scope of measurement and intensive logistics: a nacelle-based LiDAR for example, needs to be manually carried and calibrated when moving from one turbine to the next and measures a single turbine at a time. Therefore, the question of scale, leading to economic viability is imperative, and coupled with sound statistical practices based on an acceptable amount of samples, suggests that high resolution data gathering is a valuable enabler of scalable WTG performance testing.