The 2010 Windpower Expo & Conference in Dallas, held recently at the end of May, was a hotbed of technical and commercial activity this year. I had not attended the “Wind Show” since 2004, and I was amazed at the explosive growth of the event and overall industry in just six short years. This was a very substantial gathering, with about 1,400 exhibitors and 20,000 attendees.
The hottest technical topic at the show was uptime and reliability. These wind turbines are complex machines, but to be economical, they need to operate with extremely high reliability. It is no trivial matter to send out a service crew to repair an inoperative turbine. Not only is the turbine offline and not generating power revenue during a breakdown, but the remote locations and difficult physical access mean that repairs can be time-consuming and complex. Some of these wind turbines are located at the top of mountains or well offshore at sea…only reachable by helicopter!
To meet rising demand and expectations from electric utilities, wind turbine manufacturers are racing to build more reliability into their equipment. They are doing this by simplifying their designs and by subjecting their equipment to more extensive and extended reliability testing.
They are also adopting a preventive maintenance strategy, called Condition Monitoring. Condition Monitoring involves fitting the wind turbine with instrumentation that measures and tracks critical parameters over time. Every turbine will settle into a baseline set of measurements during normal operation. Data from sensors in the turbine are collected by an on-board condition monitoring system, which transmits it to a control center for aggregation and continuous analysis. If something starts to go wrong, the sensor data will start to change and at some defined point, an alert will be annunciated.
Several things could indicate a pending problem: an increase in bearing temperature, a sudden (or slow) drop in lubricating oil level, an increase in vibration, etc. It’s much better to be alerted to a potential failure before – rather than after – it occurs. Preventive maintenance can be scheduled in advance – for example, during a normal monthly inspection – thus controlling costs by avoiding emergency repairs. The fix could be as simple as re-tightening some bolts, sealing a minor leak, or topping off the lubrication reservoirs. Or, it could be something more serious that needs more extensive intervention, yet far less than would be required if an expensive component failure had occurred.
Condition monitoring is a fascinating concept and I started thinking about how this idea might be applied to equipment in other industries where high reliability is key to economic viability.