Turbine Blade Monitoring with Fiber Optic Sensors

78849S A critical goal of wind turbine manufacturers and operators is to increase the viability and deployment of wind-generated energy by reducing overall costs. The greatest wind energy cost savings can be realized through larger, more efficient turbine blades and rotor control systems. In turn, these advances will require new turbine blade materials, new manufacturing techniques, sophisticated rotor and turbine blade control systems, and much greater real-time knowledge of the structural condition of the turbine blades in operation. This latter requirement will require sensors to determine blade deflection during operation (to prevent the highly flexible turbine blades from striking the support tower), to determine and control aerodynamic loads, and to minimize structural fatigue. This project will integrate fiber optic sensor technology (specifically fiber Bragg grating technology) with a proprietary strain-to-shape algorithm. Phase I will demonstrate the feasibility of a fiber optic-based blade deflection sensor system. Finite element model predictions of the structural behavior of a CX-100 turbine blade under bending loads will be used to test the accuracy of the strain-to-shape algorithm. Sensitivity studies will be conducted to determine the necessary numbers of fiber optic sensors and sensor locations for accurate prediction of the CX-100 blade shape under static bending loads. A CX-100 turbine blade will then be instrumented using fiber optic sensor arrays and subjected to static bend load tests. The data will be processed by the strain-to-shape algorithm, and blade shape calculations will be compared to ground truth measurements. In Phase II, a new composite turbine blade will be manufactured with embedded sensors to monitor the deflection and structural condition of the blade during operation on a research turbine. Commercial Applications and Other Benefits as described by the awardee: The tremendous growth in the installed capacity of wind energy production worldwide and the need to further reduce costs through larger turbines and reduced operations and maintenance costs should provide a market with high potential for the proposed blade deflection measurement and condition monitoring system. Reduction in the cost of wind generated energy will reduce U.S. dependence on oil and natural gas, increasing national security and relieving economic constraints that affect almost everyone.