Load Analysis Of Wind Turbine Main Drive Chain Based On Measured Data

In today’s world, the energy problem is increasingly serious, wind power as a kind of endless energy has been highly valued by the energy development strategy plan. The wind power industry is developed healthily and rapidly.The main drive chain is the core part of wind turbine, which contains some crucial components. These components have high failure rate because of the bad environment and the complex operation condition. The precondition of designing the main drive chain accurately is mastering the load characteristics accurately. The load characteristics of wind turbine is random and complex. So researching the load characteristics of the wind turbine drive chain based on the measured data is of great significant for the subsequent research.In this thesis, the research object is the 1.5MW wind turbine drive chain, the complexity of the input load and the output load is aimed at. The characteristics of the load is described based on the 1 month measured data collected by the SCADA system from the perspective of mathematical statistics and stochastic process. The main research contents include the following aspects:(1) In the aspect of the input torque formula of wind turbine gearbox, the formula which has been widely used has certain rationality, but we don’t know whether it is consistent with the actual situation. Analyze the measured data collected by the SCADA system. The measured data of wind turbine gearbox is used to get the actual input torque. Compare the actual input torque with the result derived by input torque formula which has been widely used, and find that they have great deviation. The modified coefficient is proposed, and the relationship between the modified coefficient and wind speed is analyzed using the least square method. Then the input torque formula which has been widely used is modified. The modified input torque formula is more identical with the actual operational situation of wind turbine gearbox.(2) The complexity of the load that the wind turbine main drive chain is aimed at. The measured data is used to form the output load-time history. Judge the occurred moment of work load and impact load, thus the load-time history will be separated into work load-time history and impact load-time history, the work load spectrum is acquired based on the method of rain flow. The distribution model is acquired, and K-S hypothesis test is used to verify the result, thus the work load characteristics of the wind turbine drive chain is described.(3) Because the impact load of the wind turbine main drive chain is not fatigue load, so the load spectrum can’t be obtained by the rain flow count method. The occurred moment of the impact load is researched based on the random process theory, assuming that the occurred moment of the impact load is obey the rule of Poisson process. Make use of the measured impact load-time history to verify the Poisson process, and the strength of the process is evaluated according to the features of Poisson process. The parameter estimation is acquired, and the method of K-S hypothesis test is used to verify the result. Thus the impact load characteristics of the wind turbine main drive chain is described.Therefore, the load analysis of the wind turbine main drive chain based on the measured data can provide a reference to the design and manufacture. And a theoretical basis is provided for the reliability analysis and fatigue life forecast of the wind turbine main drive chain.