The Vestas V80 wind turbine (commissioned in 2004) at the wind farm in Timpberg (Brandenburg) has a long history of problems. Nine documented faults in three years. Various service providers were unable to identify the root causes and merely remedied the symptoms. This incurred downtime and repair costs to the tune of €190,000. This could all have been resolved with a professional survey and then alignment by Green Wind, and for a fraction of the cost! Sandra Zanzig (photo) from Technical Operations Management has collated the facts and costs:

The solution:

After the same symptoms kept recurring, the project managers and Alexander Donth (Green Wind Engineering, photo) decided that they might be caused by vibrations. Measurements of the turbine’s blade angles discovered a deviation of 4.2 degrees (seven times the limit of 0.6 degrees). On the day of the survey, Green Wind recorded multiple videos that showed a pronounced axial movement of the nacelle. The blade angles were adjusted immediately. Subsequent vibration measurement revealed a significant improvement. The turbine has not suffered any faults since.

Fault history:

• 03/23/2020 – Defective azimuth drive

• 05/31/2021 – Loose bolts in the gearbox supports

• 06/29/2021 – Damaged transformer (with hindsight, we know that the transformer was in constant motion due to the imbalance)

• 02/17/2022 – Damaged azimuth drive

• 06/07/2022 – Yaw feedback error

• 06/21/2022 – The same yaw feedback error recurs

• 08/15/2022 – A different yaw feedback error occurs

• 10/27/2022 – During an inspection, TOM finds significant wear on the azimuth brakes

• 11/02/2022 – Maintenance on the azimuth system

• 11/30/2022 – The blade angles are measured by Green Wind Engineering: deviation of 4.2 degrees. An alignment is performed immediately.

Repair and downtime costs:

• Repair costs: €135,000*

• Lost revenue (due to interruption): €52,100

• Costs of survey and alignment by Green Wind: approx. €5,000

*There were probably more faults with the same root cause. Only faults around the time of the survey are included here.

Are your turbines showing similar symptoms? Recurring errors cannot be fixed? Get in touch!

Photos: Pablo Castagnola