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Enhanced envelope method of acoustic emission signals and novel torque sensor design in condition monitoring of the nacelle in wind turbines

V. Kalinin, A. Stopps, J.- F. Chacon, E. Artigao, V. Kappatos, C. Selcuk, T.-H. Gan, D. Lekou and R. Ginige

Proc. of the 11th International Conf. on Condition Monitoring and Machinery Failure Prevention Technologies, Manchester, UK, 10-12 June 2014.

Abstract

The gearbox of a wind turbine experiences complex loading patterns due to the high variability of the wind and other transient events, resulting in high wear and tear leading to costly failure. In the past, condition monitoring (CM) has relied upon vibration, oil analysis and temperature monitoring. These techniques have been extensively used with some success; however they can only monitor faults at a very late stage. This paper presents a study to monitor faults in wind turbine drivetrain based on Acoustic emission (AE) and torque sensors. AE technique was used to monitor the main bearing and gearbox bearings. Several features were extracted from the time domain AE signal. In addition, envelope analysis was applied to the AE signal to find periodical patterns produced by faults such as bearing defects or misalignment. Furthermore, torque measurement have not been utilised in CM systems for drivetrain due to cost and also due to the difficulty of attachment, data reading and transmission. We have demonstrated the use of Surface Acoustic Wave (SAW) torque sensors with novel design for the attachment of the sensors to the high speed shaft and a RF rotary coupler that connects the passive sensing elements to a wireless reader.