Condition monitoring, as the name implies, monitors the condition of a component or project. The purpose of monitoring machinery health is to predict maintenance rather than reactively maintain the project. Essentially, there are three ways to operate a wind turbine:
- Wait until something fails, then repair it
- Replace components regardless of their condition at a set intervals
- Predict when maintenance will be needed and perform it then
Under the umbrella of condition monitoring, there are several technologies aimed at predictive maintenance. These technologies are adaptable, appropriate or relative at certain points in a wind turbine’s design life. Such technologies include but are not limited to:
- Oil analysis
- Vibration analysis
- Infrared thermal imaging
Combine the appropriate technology for the turbine, or the condition to be measured or predicted. The appropriate technology is the one which garners the best results for the appropriate response.
What makes condition monitoring difficult for wind is that the application is 300 ft in the air and runs at variable speeds with intermittent operation and under variable loads. The technologies listed above are meant to provide the following at a minimum:
- Measure or detect an issue
- Identify the issue
- Estimate the degradation
- Transmit that information out to appropriate parties
Most people think of condition monitoring systems (CMS) as vibration condition monitoring. Vibration condition monitoring does provide several months lead time to failures depending on the location of the assets.
Despite the great value of CMS, there are few people globally certified and experienced in vibration analysis of wind turbines. Because of this wind-industry specific shortage, there are persistent problems with its use of CMS which include short lead times for replacement components, missed calls (not recognizing the warning of impending failure), false alarms, percentage claims of efficacy, and generally a less-than-expected performance. Ironically, these issues exist only in the wind industry, not in other vertical markets that use condition monitoring.
A culture of reliability and predictive maintenance must form in the wind industry for its success. Part of this adoption is to understand who touches the system in an organization. When properly implemented, CMS can have far reaching and positive effects.
By David Clark with Bachman electronic