Pitch Systems in Wind Turbines – Reducing Load and Enhancing Turbine Safety

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All wind turbines are equipped with a certain power control feature in case the speed of the wind is too high or too low and to have a frequency coherent with the grid. The traditional and the simplest and least expensive method in this respect is a system of natural limitation known as “stall”. The blades are mounted directly on the hub at a fixed angle. When the wind speed is higher than the operational speed, the blades begin to stall.

This system regulates the power by stalling the blades when a rated power is attained. It is simple and relatively reliable, but it misses precision because it depends on the air density and of the roughness of the blades.

The second method modern wind turbines use to control power is the pitch-controlled system, which is very precise; it can control and adjust the angle of the blades several times per second if necessary. Blade pitch control is, therefore, the system which, by regulating the blade pitch angle, turns (pitches) the blades so they can take maximum advantage of the wind and, at the same time, in case of very high wind speed it functions as a brake, adjust the angle blade so that the wind goes through. Also, the increased interest in pitch system is given by the increase of the rotor size.

As mentioned above, these pitch systems continuously control the speed, when it is too high they lower the blade speed rotation and in case of low wind speed they increase the rotation speed. Therefore, pitch systems are extremely useful; they “improve the efficiency of wind energy conversion and power generation stability” . Pitch systems are usually equipped with an electrical motor, a gearbox and an electro-mechanic actuator. There are two types of pitch systems: hydraulic and electromechanical.

Article by IQPC is 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.

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Walter’s contributions to CleanTechies over the past 4 years have been instrumental in growing the publications social media channels via his ongoing editorial and data driven strategies. He is the founder and managing director of Sunflower Tax, a renewable energy tax and finance consultancy based in San Diego, California. Active in the San Diego clean technology community, participating in events sponsored by CleanTech San Diego, EcoTopics, and Cleantech Open San Diego, Walter has also been a presenter at numerous California Center for Sustainability (CCSE) programs. He currently serves as an adjunct professor at the University of San Diego School of Law where he teaches a course on energy taxation and policy.

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