power transformer capacity augmentation 3

[RRaghunath]

How do we augment the capacity of existing OFAF transformers! The transformers are in the range of 40-100MVA. Has any one tried cooling of transformer with chilled water etc.!
Look forward to your comment. Thanks in anticipation.

 

[TheBlacksmith]

Contact the OEM? I see two potential endpoints; heat, which your cooling may or may not address, it may be too deep in the core and magnetic saturation of the core, which won't be helped with chill water.

 

[dpc]

Well, the correct answer is to contact the transformer manufacturer. That said, I have seen a few transformers in power stations with water being sprayed on the radiators on a hot day.

For transformers in this size range, at least two stages of fans are generally possible, so you may want to investigate this first, if you haven't already.

Water cooled transformers are available. You might be able to replace existing radiators with a water-cooled heat exchanger.

Check out these guys:

http://www.unifin.com/index.asp

 

[prc]

raghun,It is not as easy as you are thinking.When overloading, you have to check the rating of bushing,tapchanger and lead wires toil temperature has to be brought down to take care of the extra winding gradient consequent to additional current. Best way is to contact the original manufacturer.
There are cooler makers who make portable coolers which can be connected to existing transformers to enhance cooling capacity-mainly OFAF unit coolers

 

[DTR2011]

Is this for a temporary / emergency situation or long term? Have you performed a condition assessment on the transformers? In addition to the above mentioned concerns, if these units are older, you may want to know water content of the insulation systems. You will also want to check DP (degree of polymerization).

I have seen water "assisted" systems, both in emergency situations. In one of the units, an elaborate water spraying system was made for the oil coolers. The LV bushings were in an air insulated metal enclosure. Fans were added to the enclosure to increase airflow across the bushings. This was a temporary fix for a temporary GSU, awaiting the proper unit. Consideration also has to be give to the purity of the water being sprayed, as this can cause mineral deposits and clogging of the fins on the oil coolers.

 

[RRaghunath]

Thanks to all.