Research on the application of on-line monitoring technology for bolt axial force of wind turbine

During wind turbine operation, hub and pitch bearing connection bolts are constantly subject to alternating loads. The axial force of the bolts is an important factor affecting the normal operation of the wind operation. Real-Time monitoring of residual axial force can timely feedback the operation of the wind turbine and then the health assessment of the fan structure can be realized. This paper introduces a monitoring system of axial force based on ultrasonic method for measuring bolt axial force. The system can realize the data acquisition of multiple bolts and multiple measuring points in the period. Then, we introduce the engineering application of the system and the corresponding data management system. Through the analysis of the monitoring data, scientific and accurate maintenance of the connection structure is realized, which reduces the operation cost and quality cost. This paper also tests the adaptability of the system to verify its accuracy and reliability at different temperatures.