Dry Type transformer

The difference between Oil cooled Transformer and Dry type transformer is so much that we need to write a full article. A brief of points are appended below.

Advantages of dry type transformer

1. Low maintenance cost. Needs only to be cleaned of dust.

OCT needs regular oil checking, filtration and replacement of oil which is

very costly and need high recurring expense.

2. Can be installed very close to load center hence can save low voltage

Transmission losses, which is substantial recurring saving and advantage on energy conservation step. (Considering the present day energy shortage).

3. Need comparatively less space for installation and can be integrated with VCB control unit to make a single unit to save space for HT switching panel

4. Reduce fire hazard in substation since no oil is used.

Disadvantage

Non-repairable unlike OCT if there is damage to winding if it is cast resign type.

The safety of over heating is through sensors which should be monitored regularly to ensure safety against overloading and fault conditions.

Regular dust cleaning if not carried out, can result in damage to transformer.

The cost difference and pay back period will depend on each case study which you will have to calculate depending on site conditions.

One more point to be added.

For high rise Commercial /software Parks, Dry type transformers can be located inside the main building (basement/stilt/ground floor).

The OCT transfomers has to be located away from the main building

Yes your points is another good addition.

Dear Sir,

One more point to add:

1. The LAs for R,Y & B shall be within the Transformer Tank whereas in Oil cooled Transformer it shall be Outdoor.

2. The Tap changer in the Dry Type Transformer shall be links unlike Oil filled Trans former.

Best Regards,

N.Suresh

Dear Guest

It is another good point that can be further added.The only sad point is that, it appears that the person who raised the thread did not bother to read the replies.I feel at times that it is waste of time to reply to these threads . Any way it may be useful for some others.

Regards.

Dear sir,

Please apalogize. Because I am in out of station from my office. At present moment I cannot access any mails. Now the place I am staying is also remote. Only INTRANET facility is available. SO, I am unable to access my mail account. Even now also, I got permission from my manager and using his system to access CR4. So, kindly apalogize.

Also, today I got some useful links regarding dry type transformer.

http://www.cooperpower.com/nofires/101reasons.pdf

http://www.cooperpower.com/Library/pdf/00006.pdf

Regards,

T.Kailash Kumar

thanks for your links

they are very help full to us... in Transformer Selection

sir,

It's useful for others obviously.

You don't bother about the reply of questioner but you may think on another way that it is useful for such learners as me.

Thanks a lot.

and what about maintenance of Dry trafos - as per Siemens (we use their Geafolds) the only cleaning and bolts tightening are required. but what about Insulation resistance, wiring resistance, PD, Doble test ?

I'm happy to do nothing with trafo but need to be shure it will work for some 25 years without troubling me.

(got the only specialists from India interested in this topic - send my the best to Hindustan - I did spend nearly four years overthere)