Condition monitoring of wind turbine blades using MEMS accelerometers

Wind turbine rotors in operation are subject to fatigue which is reflected as cracks and delamination in composite blades. Blade condition monitoring is becoming important to operators and insurers alike as the cost of damaged-blade repairs or replacement is very high and hence, the need for cheaper long-term solutions in the current strives for sustainable energy. In this paper, vibration/modal analysis non-destructive testing (NDT) method was used in conjunction with Signal Processing techniques to investigate the feasibility of integrating low-cost micro electro-mechanical systems (MEMS) accelerometers for blade condition monitoring as an alternative to the conventional piezoelectric accelerometers which are bulky and expensive. A rig-mounted 4.5m long blade from a 25kW Carter wind turbine was retrofitted with five MEMS accelerometers of type ADXL335 and vibration response measurements were recorded and analysed as the blade’s angle of orientation was changed by 10° from 0° to 180°. Results showed that the MEMS accelerometers are capable of measuring the blade response at each set angle of orientation. This shows potential for MEMS accelerometer integration for condition monitoring as in reality, wind turbine blades will continuously be in rotation in order to generate energy. Thus these accelerometers can perform as normal when there is a change in the blade’s orientation. In conclusion, MEMS accelerometers have a great potential to be integrated easily either retrofitted externally or embedded in blades at manufacture for condition monitoring at marginal cost.