| The world’s increasing attention to clean energy has led to the rapid development of the wind power industry,with wind energy as the main focus.As an important infrastructure for converting wind energy into electrical energy,the dynamic characteristics and safety of wind turbines have always been widely concerned.To understand the structural characteristics of wind turbines under different environmental and working conditions,long-term monitoring was carried out on a 2.0 MW wind turbine.Statistical analysis was performed on the vibration response of the wind turbine tower and environmental factors,and the influence of different operating conditions on the modal parameters of the wind turbine tower was studied.Based on the initial structural parameters of the wind turbine,a finite element model was established,and the finite element theoretical model was accurately modified based on the measured data of the wind turbine.The main research contents of this paper are as follows:(1)A health monitoring system for the wind turbine tower structure was designed based on the characteristics of the wind turbine structure,and longterm monitoring was conducted for three years.The vibration response of each measuring point of the wind turbine was analyzed,and it was found that the RMS value of the tower vibration amplitude peaks at wind speeds around3m/s and 8m/s.Based on the random subspace modal parameter identification method,the Data-SSI,Comb-SSI,and Cov-SSI identification methods were compared from the dimensions of spatial state,identification speed,identification accuracy,and anti-interference performance,and the Cov-SSI method had the best overall performance,so it was chosen for modal parameter identification.(2)The operating conditions of the wind turbine were divided in conjunction with the actual operating conditions of the wind turbine,and the changes of the first three orders of frequency and damping ratio of the wind turbine tower under different operating conditions were discussed in detail,and it was found that the damping ratio of the structure decreased and the stability of the structure weakened when the wind turbine was in the starting state.The Campbell diagram of wind turbine in X-direction and Y-direction is plotted,and it is found that the wind turbine blade speed at 3 f(0.35Hz)is close to the tower fundamental frequency,which is easy to cause structural resonance,and it is observed that the blade speed jumps when the wind turbine speed is 7rpm,which is consistent with the non-linear jump phenomenon from the Sommerfeld effect pre-resonance jump to postresonance jump,and explains the tower at the wind speed of 3m/s The phenomenon of peak RMS value of vibration amplitude verifies the resonance of wind turbine.To provide actual measurement data support and reference index for the design and condition assessment of wind turbine structure(3)Based on the basic design parameters of the wind turbine structure,a finite element theoretical model is established,and the measured modal parameters of the wind turbine tower are used as the benchmark for modal correction.The relative sensitivity of the design parameters of the finite element model to the structural frequency is calculated by sensitivity,and the two design parameters with higher sensitivity are taken as the target correction variables,and the ideal target model is calculated by the objective function and constraint analysis.The results show that the corrected finite element model of the wind turbine tower structure has small errors with the modal parameters of the measured data,and the model can be used as a benchmark model for hydrostatic analysis and condition evaluation. |
