Experienced entrepreneur and engineer Carl Byington worked for Impact Technologies, Sikorsky Aircraft, and Lockheed Martin for many of his professional years. In these roles, Carl Byington became an expert in prognostics and health management (PHM) technologies and next-generation condition-based maintenance plus (CBM+) solutions. He currently consults in these technical areas at his PHM Design company, located in the Atlanta, GA area.
Rotorcraft and wind turbines are both susceptible to critical drive train failure modes involving bearings and gears. The helicopter community has developed sophisticated health and usage monitoring systems (HUMS) to track damage accumulation on critical components and detect incipient faults. Health and usage monitoring systems typically consist of a variety of onboard sensors, data acquisition systems, and signal processing and analysis algorithms. The acquired data may be processed onboard the rotorcraft or on a ground station (or a combination of both) providing the means to measure against defined criteria and generate instructions for the maintenance staff and/or flight crew for intervention. Application of HUMS technology to wind turbine drive trains has the potential to significantly reduce maintenance costs and increase turbine availability by enabling condition-based maintenance (CBM).
The wind turbine industry has experienced an array of drivetrain failures including spalled bearings and fractured gear teeth. Some of these failure modes are largely attributable to unexpected and/or excessive loading conditions. Such drivetrain failures often entail expensive repairs and can have catastrophic consequences for the turbine. The helicopter community faces many of the same challenges from uncertain loads and dire consequences associated with drivetrain failures. Thee helicopter community addressed these risks through the use of drivetrain health and usage monitoring systems (HUMS). Such HUMS oil debris and advanced gear/bearing vibration technologies can be used to help the wind turbine industry.
Information from HUMS enables implementation of a new maintenance paradigm that can improve reliability, availability, and maintainability of wind turbines while simultaneously reducing maintenance costs. Under the simplest maintenance paradigm, reactive maintenance, equipment is allowed to run until it fails without maintenance intervention. Reactive maintenance yields low reliability and high costs due to missed opportunities to detect and repair faults, secondary damage (progression of failure to a severe state), large logistics footprint (parts and labor) to cope with unexpected failures, and lost production while equipment awaits repair.
Preventive maintenance can improve equipment reliability (number of failures) by periodically overhauling equipment before it wears out. To avoid unexpected failures in equipment that has an uncertain service life, preventive maintenance must be performed well in advance of the mean time to failure. Consequently, preventive maintenance achieves high reliability at the cost of performing premature maintenance which includes frequent interruption of production for planned maintenance, high labor costs, and high parts usage.
Condition-based maintenance (CBM), on the other hand, enables high equipment reliability and low maintenance costs by eliminating the need for unnecessary overhaul activities while simultaneously allowing repairs to be performed on a planned basis. Condition monitoring provides insight into the “health” of individual pieces of equipment so that maintenance decisions can be made on a case-by-case basis rather than on fleet wide averages. Detection of faults in their early stages provides an opportunity to order parts, schedule personnel, shutdown the equipment before serious damage occurs, and minimize the disruption of production. Furthermore, insight gained from equipment condition monitoring reduces uncertainty regarding the “health” of critical internal drivetrain components and therefore eliminates the need for preventive maintenance. In other words, maintenance is performed only when necessary.
The value proposition for wind turbines and specific technologies involved is summarized in a paper by Carl Byington, et al. It is available for download here:
Carl Byington may be contacted for specific consulting engagements at:
https://phmdesign.com/contact-us/
