Wind Gerators failure

[petronila]

Dear All,

First I want to wish you Merry Christmas and Happy New Year I know is soon but the new year is right in the corner.

Second I am interested in to have a good information about the most important failures electrical and mechanical in wind generators.

Thanks for the inputs

Best Regards

Carlos

 

[MikeHalloran]

The most important failure is the one that plunges _me_ into darkness.



Mike Halloran
Pembroke Pines, FL, USA

 

[MiketheEngineer]

They break and fall over

 

[nifrabar]

Apart from lack of wind I don't see a real problem with wind-driven generators. In Egypt I saw about 1000 windmills together all spinning and so generating cheap power. Of course you can't rely on that powersource only.
Once the system is well engineered I can't see why they e.g. will break and fall over.
-Bart

 

[Skogsgurra]

Bearings and gear/transmission fail often. Repair costs are high because you have to wait for a calm day in a region selected because of high wind.

Gunnar Englund

http://www.gke.org

--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

 

[nifrabar]

Often failure of gear/transmission : imhu > bad mechanical engineering
-Bart

 

[cswilson]

I have worked on a variety of wind generation projects over the years, so I have learned a fair bit about the design and reliability concerns.

In general, the top of a wind turbine generator is a very harsh environment for both electrical and mechanical components. My understanding, as with other posters, is that the gearing/transmission has been the least reliable component in these generators.

Fluctuating wind loads tend to put tremendous strains on all of the mechanical components. A lot of recent work has gone into trying to reduce these stresses and so improve reliability, with techniques like real-time control of the blade pitch.

Newer designs generally do not have the generator tied directly to the grid. Instead the generator power is rectified to DC and then inverted to the 50 or 60 Hz grid. This permits the generator to accelerate much more in gusts and decelerate in lulls, which dramatically reduces mechanical stresses. The process is basically the reverse of a VFD, which takes fixed 50/60 Hz power in, and outputs variable frequency and magnitude.

However, now you are putting a lot of very expensive electronics in a very nasty environment, which introduces potential failure mechanisms of its own. I'm guessing that the recent fire in a Scottish wind turbine in very high wind conditions was caused by inadequate overvoltage protection.

Curt Wilson
Delta Tau Data Systems

 

[MiketheEngineer]

Obviously all the mechanical and electrical components can/do fail eventually.

So does the paint!! Some of these things are over 200' to the hub!!

Just getting there and putting in parts or painting them is a MAJOR under taking!!

 

[rterickson]

Poor (lowest installed cost) system design can be a real problem (usually for the owner/operator more so than the developer).

Things like:

Cheapest possible live-front distribution transformers used as GSU's without regard to service conditions;

Series connection of units (failure/maintenance requires taking all turbines upstream off line);

direct burried colector cables;

No bypass/maintenance provisions.

 

[LSpark]

We've had quite a lot of transformer problems in the wind turbines, I suspect that's mainly because we get them as cheap as possible so not from the most reliable manufacturers/factories.

Th rumour I heard for the one that caught fire in Scotland was that it was a fairly old design and the mechanical brake gave way during the gales so the turbine basically oversped as the braking system failed.

 

[petronila]

Dar All

Thanks for all inputs. You are right about the problems experienced in wind generators,and the low cost is one of then another one is the mixed engiennering, the wind generators could be work with converters and sometimes the generator was not made by the same converter manufacturer and the same for the transformer and other parts. I was found an interesting paper in IEEE: A Review of Electrical Winding Failures in Wind Turbine Generators by Kevin Alewine & William Chen.They made a good analysis of the failures including photos and classification by power and failure type.

The paper is interesting and I think you will find usseful.

Best Regards

Carlos

 

[dicer]

I would be curious of how often the main bearing needs replacement? And what is the replacement procedure? Removing the blades etc at 200 foot high? Must be a huge crane.