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Freezing Rain Detectors Provide Early Warning Of Turbine Icing.
publication date: Jul 30, 2009
Danger to people and property caused by ice shedding at high speed from wind turbines is often raised as a concern in discussion about wind farms. However, for operators icing presents two quite different problems; firstly, blade aerodynamics are adversely affected causing the rotor to slow dramatically, reducing power output, and secondly, rotors can become imbalanced causing stress on the turbine gearing. Chunks of ice being hurled great distances is actually extremely unlikely because the rotors turn much slower when iced and where ice is shed it generally shatters and falls around the foot of the turbine. Ice build up is a consequence of a relatively rare weather phenomenon known as freezing rain or an ice-storm rather than simply due to frosty conditions. Freezing rain occurs when rain droplets pass through a very cold band of air near to the earth, this cold air supercools droplets to below freezing but they remain in liquid form. When these drops make contact with a cold surface they instantly freeze, coating the surface in an icy glaze; subsequent drops build upon this to coat the entire surface. The low power sensor works by detecting changes in resonance on a probe which vibrates at high frequency. Almost immediately an event is detected the sensor switches on a heater and sheds its ice to reset and start detecting again, in this manner the sensor will continue to provide warning until the event has finished. The sensor is compatible with all current Campbell Scientific Data Loggers. Details can be found by visiting http://www.campbellsci.co.uk/index.cfm?id=2050 Contact: |
