Experimental Study On Icing Monitoring And Anti-icing Or Deicing Of The Wind Turbine Blade

In recent years, as a widely recognized renewable energy source, wind power hasbeen explored at an increasing rate in most developing countries in order to meet therapidly increasing energy demands and the investment in the construction of windfarms have been increasing remarkably. However, wind turbines operating in coldregions or at high altitudes are frequently facing icing conditions during winteroperation. Icing in wind turbine blades significantly affects the aerodynamicproperties of blades causing loss of power production, mechanical failures due toadditional unsymmetrical loads, and even possible stop of operation. In order toguarantee the wind turbines installed in cold regions operating normally in freezingwinter weather, an icing monitoring method and a novel anti-icing or deicingtechnique are proposed, and some related experimental studies are carried out in thisthesis. The specific study is listed as follows:(1) An icing monitoring method approach for the wind turbine blade based onpiezoelectric lead zirconate titanate (PZT) technology is proposed. By the use of PZTpatches on a model blade acting as actuator and sensors, experimental study of icemonitoring under different ice thickness is carried out. And the wavelet packet energymethod is employed to analyze the signal data. It turned out that the wavelet packedenergy of received signal decreases with the increase of ice thickness. Thus, icyconditions of the tested structure can be monitored based on the changes in waveletpacked energy value.(2) Conducting the resistance stability test of the carbon fiber composite on theaspect of resin infiltration and temperature variations. The results show that theresistances of carbon fiber composite material have certain stability, which provides areliable guarantee when apply to prevent icing of the wind turbine blades in practice.(3) Carrying out the anti-icing and deicing test based on the scale wind turbinemodel blade in static condition at both the room temperature and the low temperature(in a refrigerator) to study the temperature rising performance and the ice meltingefficiency of the heated material under different temperature circumstances anddifferent input voltages. The results manifest that the model blade is not only heatedquickly and steadily, but temperature field of the blade surface is evenly distributedafter power on, which has very efficiency for anti-icing and deicing of wind turbine blade.(4) A wind turbine model driven by a motor is designed, on which experimentalstudy is carried out to validate the deicing performance of the blade in an environmentsimulation laboratory. The test conditions include different temperature circumstances,different input voltages, and different rotation speeds. Results indicate that thedemand of anti-icing and deicing of the blade in rotation condition can be realized,and the surface temperature of the model blade is reduced from root to tip. Therefore,the tip part is a critical anti-icing area due to the lowest surface temperature of thewhole wind turbine blade.