A downed turbine is a money-losing turbine, and so knowing the current status of a wind turbine at any point in time is important for achieving a high uptime record. Sensors on a wind turbine therefore are extremely important for managing the production of the machine. But there are many challenges for sensory technology on utility scale turbines, including the following:
• Determining if wind speeds are sufficient for turbine startup is often limited by location options for anemometers and the complexities of blade and wind interaction.
• Sensor failures are often difficult to detect and diagnose because of calibration errors and other difficulties.
• Traditional wind turbine technology has relied on electrical sensors, but as systems get larger (wider and taller) and more complex, so do the electrical components. When lightning strikes, there’s a significantly increased potential for total system failure.
But where old sensory technologies have failed, innovative sensing systems will fill the gap by overcoming these conventional challenges.
For instance, lidar sensors, or light detection and ranging optical remote sensors, which have been traditionally used in archaeology, geology, seismology, and by NASA for atmospheric physics, are being tested in wind farm settings. Here they are being tested to evaluate wind profiles, including wind turbulence and shear parameters as well as speed and direction, an innovation that is especially useful for hurricane situations and conditions at airports. One of the benefits of this type of sensing technology is that it can be deployed with off the shelf telecommunications equipment and are based on solid-state sources, making it possible to improve reliability at a lower cost per module.
The new Optical Sensor Interrogator developed by Micron Optics is one such system. It receives, reads, transmits, and stores the data produced by a fiber Bragg grating (FBG) optical sensing system. These sensors are embedded in fiber optic cabling within the blades, and can measure 80 sensors ten times per second, thereby increasing the quantity and accuracy of the data being sensed.
The monitoring and control software can analyze the information from the system and adjust the turbine in real time to react to changes in wind speeds to reduce blade stress. The sensors also monitor and report on defects and imperfections in the blades, adjust pitch, rotate the turbine, or even shut down the entire system if necessary.
New sensing technologies allow turbine controllers to react more quickly to determine where failures originate and minimize downtime as much as possible. More data also makes it possible for farm managers to optimize turbines as they interact with one another in large installations. The next few years doubtless will result in significant sensory advances in the industry which will increase the financial viability of wind turbines at all scales.
Article by IQPC, a leading organizer of about 2,000 worldwide conferences, seminars, and related learning programs every year. The company is organizing the 2nd International Conference E/E Systems for Wind Turbines 21 – 23 May, 2012 at the Swissôtel Bremen, Germany. Free whitepapers, articles and podcasts on grid integration of offshore wind energy are available on the website.