Gearbox Monitoring: the importance of acting early

The gearbox is one of the most critical components of a wind turbine, its replacement cost often reaching six figures. It is no surprise then that owners and operators actively work to prevent its premature failure which aways leads to prolonged downtime and production losses.

In order to detect failing gearboxes at an early stage, i4SEE provides its customers with a holistic overview of the gearbox by monitoring three different data streams: 10min SCADA data, vibration-based condition monitoring data and particle count data.

One of i4SEE’s analysis techniques involves examining the gearbox oil temperature and flagging temperatures exceeding the learnt “thermostat limit”, i.e. the limit at which the cooling system switches on to maintain a healthy operating temperature. This limit is usually well below the manufacturer’s threshold temperature at which the wind turbine is shut down in order to protect the gearbox from permanent damage.

Whilst monitoring CGN Europe Energy’s wind fleet, it became clear that a turbine’s gearbox oil temperature was regularly exceeding the thermostat limit learnt by our technology, indicating a probable fault with the cooling system.

To protect the gearbox, the turbine was curtailed to partial load and the O&M service provider was alerted. It took a few months for a detailed inspection to be performed and in the meantime, despite the curtailment implementation, the gearbox continued to operate at relatively high temperatures.

Once the inspection was performed, it was found that the gearbox fan was defective and needed exchanging. The fan was eventually replaced and the gearbox oil temperature has since returned to normal levels.

However, the gearbox particle count, which also provides an indication of the health of a gearbox, has remained high and indicates the gearbox is still suffering from permanent damage, potentially caused by prolonged operation at high oil temperatures.

The i4SEE GearDrive™ application helped CGN identify a defective gearbox fan, allowing us to raise the issue with the O&M service provider and ensure the fan was replaced.

“Unfortunately, it took some time before the issue was resolved and whilst i4SEE helped us avoid a gearbox failure, acting sooner could have meant less stress for the gearbox which seems to have suffered from operating at higher temperatures for a significant amount of time,”

Paul-Henri Durand.