Replacement of a V90 yaw ring in tough weather conditions

2016-Nov-23th

It was far from an ordinary task the wind turbine technicians from Connected Wind Services in Falkenberg faced, when replacing a damaged yaw ring on a V90 wind turbine in Dintestorp, Jönköping. In fact, this was only the second time that a yaw ring had been replaced on this type of wind turbine in Sweden.

- The first yaw ring on a V90 was exchanged in 2009 and for us it was the first time we faced such a task, explains Magnus Mjörnå, Area Sales Manager at Connected Wind Services in Sweden.

The wind turbine, which is privately owned, is a Vestas V90 MK5, and a total of 10 working days, including the crane work, was originally calculated to perform the replacement of the damaged yaw ring.

Challenging conditions were no match
The weather tried its best to complicate the assignment with snowy weather and below zero temperatures. Despite one whole day of heavy snowfall and wind gusts which made it impossible to work, the task was nevertheless solved in less than a week.

Competent workforce
- It could only be done so fast through thorough preparation and because we have very competent and skilled employees with years of experience who are flexible and able to adapt to unforeseen situations, emphasizes Magnus Mjörnå.

During the project unexpected challenges appeared. Even before the dismantling of the nacelle, the wind turbine technicians discovered a damaged gear on the yaw ring, meaning that the nacelle could not be rotated to the correct position. Therefore, as one of the first things, the technicians from Connected Wind Services had to exchange the damaged gear before work could continue.

Successful and quick replacement
After dismantling the blades and the nacelle, and lowering the entire rotor and nacelle to the ground, it only took the technicians from Connected Wind Services three hours to replace the damaged yaw ring with a new one. Both the blades and the nacelle were lifted and remounted on the same day. The following day was used to retighten all bolts, reinstall the four yaw motors that operate the yaw ring and finally rewire all cables. That same evening, the wind turbine was reconnected to the network.

- The cooperation between our various teams worked quite brilliantly, so we are both proud and satisfied. This task has also given us valuable experience within an otherwise very rarely performed project, says a happy Magnus Mjörnå.

Under normal circumstances, a yaw ring should last the entire lifetime of the wind turbine, as it is one of the main components of the wind turbine, and tremendously difficult to replace, requiring a complete removal of the rotor and the entire nacelle. In this case, the damage was sudden and fortunately covered by the owner's insurance company. A similar new wind turbine would cost approx. 3.3 million euros.

About Connected Wind Services

• One of the leading independent service providers in Europe
• Provides service and maintenance as well as complex service projects on a great variety of wind turbines from different brands
• Solid local presence throughout Europe
• Strong service network with 40+ service teams
• 1500+ wind turbines in service
• 30+ years of experience and Europe’s first Independent Service Provider
• Headquarters in Denmark with subsidiaries in Sweden and Germany
• Large main component and gearbox refurbishment factory at its disposal, located in the former Nordtank / NEG Micon factory in Denmark