Case Studies / Suzlon S88 Retrofit Solution

Wind Turbines in a distance


FT Technologies worked closely with a wind farm owner operating Suzlon S88 wind turbines to retrofit FT ultrasonic wind sensors onto their platforms. Their existing wind sensors proved to be both expensive and challenging to acquire, with many units in the US supply chain being unreliable due to them being repaired units. The customer, drawing from previous positive experiences with FT Technologies’ sensors in Arctic climates, embarked on extensive A/B testing of various ultrasonic sensors to address these concerns. FT Technologies emerged as the clear winner in these tests, demonstrating superior performance, especially in cold climates and icing conditions.


In retrofitting wind sensors for wind turbine control, ensuring the accuracy of the Nacelle Transfer Function (NTF) is paramount. This necessitates a period of thorough data logging comparisons to establish precise offsets and slopes. These parameters can be fed into the turbine Programmable Logic Controller (PLC) or configured directly into FT Technologies’ wind sensor User Calibration Table (UCT).

Previous analyses indicated that Suzlon turbines require a 0.91 offset correction factor to compensate for the unique geometry of the nacelle roof. The Suzlon S88 nacelle roof’s complex design which accounts for the geometry of cooling vents and the SFS resistor packages, induces inaccuracies of a higher-than-actual wind speed reading.


Mechanical installation of the FT722-A-DM50 wind sensor (fig. 2) proved to be straightforward and intuitively simple. Its pipefitting seamlessly matched the footprint of the original incumbent wind sensor without requiring modifications. Similarly, the electrical installation was equally streamlined, requiring minimal adjustments to the top box and the addition of an extra jumper wire.

The evaluation FT wind sensor worked immediately upon installation and provided the correctly scaled analog outputs without needing to modify the sensor parameters. Drawing from the customer’s previous positive experience with FT wind sensors in Arctic conditions, the decision was made to proceed with a larger deployment of FT wind sensors for use in retrofits.

By opting for FT wind sensors, the customer not only addressed supply chain risks associated with their incumbent wind sensors; but have ensured enhanced accuracy and reliability in wind speed measurements, crucial for wind turbine control. The simplified installation process underscored the practicality and compatibility of FT Technologies’ solutions, promising improved operational efficiency and reduced downtime for the Suzlon S88 wind turbines.

Image credit:

Figure 1:, Creative Commons By 2.0 https://commons.wikimedia.orgwindex.phpcurid=37262818
Figure 2: FT722-A-DM50 on a pipe