TEMPERATURE COMPENSATED FBG STRAIN SENSORS FOR MONITORING OF WIND TURBINE BLADE

摘要

The size of wind turbine blades has gradually been increased to improve the efficiency of wind power generation in recent years. These big wind turbine blades may experience harsh environment such as gust wind, bird strike, and lightning etc that make some damages in the blades. Therefore, the monitoring of strain and temperature of the blades is very important to operate them safely, and can reduce their maintenance costs. Fiber optic sensors have been deeply considered in blade damage detection techniques such as acoustic emission and ultrasonic detection. However, fiber optic sensors need to compensate temperature effects in strain sensing signals. In this study, a dual fiber Bragg grating (FBG) sensor probe molded with epoxy is proposed to measure the strain with temperature compensation of wind turbine blades. Both temperature and strain dependencies of the epoxy molded FBG probe are investigated and analyzed. Also, some FBG sensor signals are acquired from a blade bending test and analyzed to get the deformation behavior of the blade.