New condition monitoring technique could reduce wind energy costs
16 August 2015
Engineers from the University of Sheffield have developed a novel technique to predict when bearings inside wind turbines will fail.
The method, published in the journal, Proceedings of The Royal Society A and developed by mechanical engineering research student, Wenqu Chen, uses ultrasonic sound to measure the load transmitted through a ball bearing in a wind turbine.
When a bearing is subject to a load, its thickness is reduced by a very small amount due to elastic deformation, and the speed of sound is affected by the stress level in the material. Both these effects change the time of flight of an ultrasound wave through a bearing.
The new method measures the transmitted load through the rolling bearing components directly. It uses a custom-built piezoelectric sensor mounted in the bearing to measure the time of flight and determine the load. This sensor is less expensive and significantly smaller than currently available devices, making it suitable for smaller turbines. It can also provide a better prediction of the maintenance needed, saving money in servicing.
Professor Rob Dwyer-Joyce, co-author of the paper and Director of the Leonardo Centre for Tribology at the University of Sheffield says the technique can be used to prevent unexpected bearing failures, which are a common problem in wind turbines. "By removing the risk of a loss of production and the need for unplanned maintenance, it can help to reduce the cost of wind energy and make it much more economically competitive," he adds.
The new technology has been validated in the lab and is currently being tested at the Barnesmore wind farm in Donegal, Ireland by the company, Ricardo.