Wind Turbine Step-Up Transformer

[VTer]

Good Day,

I hope I am in the right forum, but can someone please provide me some reputable manufacturers for the Wind Turbine Step-Up Transformers in US, preferably the Midwest. The ones I am looking for are for small wind turbines in the range of 500kW and less. I appreciate the help. Thanks!

"Throughout space there is energy. Is this energy static or kinetic! If static our hopes are in vain; if kinetic — and this we know it is, for certain — then it is a mere question of time when men will succeed in attaching their machinery to the very wheelwork of nature". – Nikola Tesla

 

[rbulsara]

They would be the same mfrs as who make normal power transformers. There is nothing really special about wind turbine step-up transformers per say than any other step-up transformer. Just let them know the application.

Rafiq Bulsara

http://www.srengineersct.com

 

[MAGTiger]

Try Olsun Electric in Richmond Illinois.

http://www.olsun.com

Neil

 

[VTer]

Thank you Rafiq. My understanding is that wind-turbine transformers are subject to frequent thermal cycling due to the effect of rapid and irregular loading which cause repeated thermal stress on the windings, requiring more robust winding construction. In addition, when lightly loaded or idle, core (no-load) losses can became a more significant factor in overall efficiency and economics in comparison to load losses. I believe that there are manufacturers out there that specifically build wind turbine step-up transformers for the reasons stated above, I just need reputable manufacturers in the Midwest area if there are any. Thanks!

"Throughout space there is energy. Is this energy static or kinetic! If static our hopes are in vain; if kinetic — and this we know it is, for certain — then it is a mere question of time when men will succeed in attaching their machinery to the very wheelwork of nature". – Nikola Tesla

 

[VTer]

Thank you Neil.

"Throughout space there is energy. Is this energy static or kinetic! If static our hopes are in vain; if kinetic — and this we know it is, for certain — then it is a mere question of time when men will succeed in attaching their machinery to the very wheelwork of nature". – Nikola Tesla

 

[rbulsara]

Vter:

The efficiency considerations due to loading profile or any other spec items apply equally to any other power transformer. You still need to spec what you want or need but the any reputed mfr who makes regular power transformers would be able to meet those requirements. Plus you are talking about small units.

Rafiq Bulsara

http://www.srengineersct.com

 

[DTR2011]

If it is any help, the last 3 wind projects I have commissioned have utilized ABB padmount units. These utilize "Bio Temp" oil, which is also more environmentally friendly.

Winding configuration varies, but many use 34.5kV Delta to 690V Wye. At the collector substation 34.5Y - 480V Delta are used for grounding transformers (1 per feeder). The utility tie transformer is wye-wye with a delta tertiary.

There appears to be nothing special about the GSU units (looks like a padmount), other than on the HV side it is a dead front loop feed with an internal primary switch. On the project I am on right now, it is 150kV BIL, cu windings.

I have seen some units that had problems, but I believe this was more of an issue with wye-wye configuration and internal fusing on the HV side.

 

[alehman]

smallgreek - can you provide any more details on the problems you mention with wye-wye connections and internal fusing?

Alan
“The engineer's first problem in any design situation is to discover what the problem really is.” Unk.

 

[prc]

I have seen utility transformer with star/delta also to collect power from wind farm.
When you say wye/wye transformer with internal fusing on HV,hope you are referring to generator transformer.Normally with large generators the step up transformer is always star/delta to avoid zero sequence currents entering in to stator windings on an LG fault on HV. Then why at wind farm, delta/ star transformer is used as step up transformer?

 

[Marmite]

In many respects windfarm electrical designs have more in common with distribution systems than power plants. One of the reasons being that the wind turbine is not a reliable source of fault current. The wind turbine 690V electrical system will be solidly grounded at the step up transformer star point. The turbine electrical system is 690V three phase plus neutral.
Regards
Marmite

 

[DTR2011]

smallgreek - can you provide any more details on the problems you mention with wye-wye connections and internal fusing?

If I recall correctly, about 20 units were gassing. As mentioned earlier, the thermal cycling had caused poor connections at the internal fuse connections.

These (in my opinion) were poorly specified. The (H0-X0) neutrals were internally connected. Not much could be done in terms of diagnostic testing. Someone wanted an inexpensive transformer and they got it.

My company does maintenance for several large windfarms in Minnesota. The units that are Delta / Wye (described) above seem to be holding up well over the years

 

[VTer]

The turbines we are possibly looking at have rectifier/inverter assemblies, that based on the turbine manufacturer requires a 480V solidly grounded wye transformer on each turbine, LV side. Understandably, for the utility interconnect side they have no specific requirements and this is where we come into play. We are investigating a couple of options to tie this system into the distribution network. I was just interested in reputable manufacturers that I can talk to, that dealt with small wind-turbine step-up transformers before. I am hesitant of wye/wye step-up transformers for multiple reasons, of which some where stated above. Then again, the system is so small that it would not pay to go with HV delta and a possible separate grounding transformer if required by the local utility, from which I am waiting a response still. My question to you is that since the inverter shuts down the turbines immediately after the utility source goes down, do you see the need for a grounding transformer if we were to go with xfmr HV delta connection to the utility? There is no way to back-feed to utility through the step-up wye/delta xfmr when the utility is down. The utility where we would connect to is a grounded wye system by the way. Am I overlooking anything on this? Thanks!

"Throughout space there is energy. Is this energy static or kinetic! If static our hopes are in vain; if kinetic — and this we know it is, for certain — then it is a mere question of time when men will succeed in attaching their machinery to the very wheelwork of nature". – Nikola Tesla

 

[jghrist]

http://www.beckwithelectric.com/docs/tech-papers/DG_1547_Paper.pdf

discusses different tranformer connections for distributed generation.

 

[rterickson]

An alternate opinion:

http://www.pddnet.com/editorial-tom...eakest-link-in-the-wind-energy-supply-031910/