基础环式风力机基础在线监测与损伤评估方法研究

针对风力机运行及基础环式基础风致疲劳损伤特点，提出“上下联动，动静结合”的在线监测和损伤评估方案，即基于基础环水平度测量结果确定线性差分式位移传感器（LVDT）位移计安装位置，并将实时采集的位移信号接入风力机数据采集与监控（SCADA）系统，可实现与上部机组参数同步采集、分析与损伤评估。现场监测结果表明，风力机在启停机、偏航、高中低速运行平稳段等常见工况下轮毂转速与基础环水平度的相关系数均为0.8及以上，为极强相关，故可将轮毂转速视为基础所受的“等效荷载”；通过绘制启机工况下的轮毂转速n-基础环位移Δ曲线，确定临界轮毂转速下限nd和上限nu以及斜率k等曲线参数，可评估风力机基础疲劳损伤程度；通过绘制机头方位角θ-基础环最大水平度Δmax曲线，可确定下法兰周边混凝土磨损性空腔分布区域及大小，为后期基础注浆提供明确的加固位置。

RESEARCH ON METHOD OF ON-LINE MONITORING AND DAMAGE ASSESSMENT OF WIND TURBINE CONCRETE FOUNDATIONS WITH EMBEDDED RING

According to the characteristics of wind turbine operation and the wind-induced fatigue damage of the embedded ring foundation, an online monitoring and damage assessment scheme of "upper and lower linkage, dynamic and static combination" is proposed. In other words, the installation position of the LVDT displacement sensor is determined based on the measurement results of the embedded ring levelness, and the displacement signals collected in real time are connected to the SCADA system of the wind turbine, which can realize synchronous acquisition, analysis and damage assessment with upper unit parameters. The field monitoring results show that the correlation coefficient between hub speed and embedded ring levelness is 0.8 or above under common working conditions such as start and stop, yaw, stable operation at high, medium and low speeds, which is extremely correlated. Therefore, it is feasible to regard the hubspeed as the "equivalent load on the foundation of the wind turbine. The fatigue damage degree of wind turbine foundation can be evaluated by drawing the curve of hub speed N-foundation ring displacement Δ and determining the curve parameters of critical hub speed, such as lower limit n_d and upper limit n_u and slope. By drawing the curveof the azimuth angle of wind turbine headθand the maximum level of the embedded ring Δ_max, the distribution area and size of the concrete wear cavity around the lower flange can be determined, which provides a clear reinforcement position for the later foundation grouting.