| In recent years,wind farms in China have developed rapidly,but the problem of wind farm icing can not be ignored.Blade icing will affect the stable and efficient operation of wind turbines and bring huge losses to the economic benefits of wind farms.At present,the research on the influence of icing on the output power of wind turbines at home and abroad is mainly theoretical analysis and simulation,which has limitations.Therefore,combined with natural icing and simulated icing,the influence of blade icing on the power characteristics of wind turbines is studied experimentally,which can provide a reference for the performance evaluation of wind turbines in icing conditions,which is of great significance for the safe and stable operation of wind turbines.Based on 300 kW wind turbine of Xuefeng Mountain Natural Icing Test Station of Chongqing University and 100 W horizontal axis wind turbine of Chongqing University State Key Laboratory of Power Transmission Equipment & System Security and New Technology,the effects of blade icing on the power characteristics of wind turbines are studied by using two test methods of natural icing and simulated icing,which provides data support for quantitative study of power characteristics of wind turbines.The main work and achievements of this paper are as follows:(1)The effects of different icing conditions on the power characteristics of wind turbines under natural conditions are studied experimentally,and the power curve,rotational speed curve and wind energy utilization coefficient curve of wind turbines under natural conditions are obtained.The results show that the output power of wind turbine decreases as the icing condition becomes more and more serious at the same wind speed.For four groups of test groups(ice thickness of blade spreading to 95% section front is 9 mm,52 mm,76 mm,319 mm respectively),the maximum power reduction of wind turbine is 5.8%,56.9%,87.7% and 99.7% respectively(shutdown)compared with the clean group.With the aggravation of icing condition,the decrease of rotational speed will increase,and with the increase of tip speed ratio,the wind energy utilization coefficient increases first and then decreases.When the wind turbine operates at limited power,the pitch angle increases with the increase of wind speed.After mild icing,the pitch angle-wind speed curve decreases as a whole with the increase of power limit value.(2)For small wind turbines,based on streamline ice and horn type ice on blades,using viscous material simulation method,the effects of icing weight,stagnation point thickness and other factors on the power and rotational speed of wind turbines are systematically studied.The results show that at the same wind speed,with the increase of icing weight and stagnation point thickness,the average power loss,the decrease of the maximum instantaneous power and the average rotational speed loss of wind turbines increase gradually.(3)By simulating the wind turbine icing in the laboratory,the changes of wind turbine power and rotational speed under different wind speeds were studied.The power and rotational speed curves of wind turbines under different icing degrees and different ice shapes were obtained.The aerodynamic performance changes and power losses of wind turbines caused by blade icing were analyzed.Compared with streamline ice,horn type ice will bring more aerodynamic load loss,which has greater impact on the overall aerodynamic performance of blades and power characteristics of wind turbines. |
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