Selection of a Distribution Transformer

http://cr4.globalspec.com/thread/76967

Your total load is 3000KW which is about 4,900 Amps at 415V therefore your Distribution transformer will be about 4MVA capacity. If you want to consider for the further additional load then you need to redesign your electrical loading system.

If you don't have any experiences. pls engange a consultants to do it for you.

I would size it like this:

Anticipated Maximum Demand x a factor of cushion, (say 1.2)

Who calculated/assumptions made the max demand and load factor?. What kind of load is it supplying?. Are there big motors,what type of starters are used,give more details.

Dear pnaban,

It is a factory load, which is having all sort of loads such as motors ranging from 0.375 Kw to 250 Kw, at 415 volt, 50 Hz supply, heating load of approximately 500 Kw, HVAC system, AHU etc.

load factor considered is 0.7.

Is this information is enough to calculate the KVA rating of the transformer?

Subhash

If your max demand is 2625kVA,3MVA transformer would be OK provided the number of large motors(250kW) is not much.You should consider starting methods used for large motors to limit starting/inrush current. No breakdown of HVAC load was given.Information provided by you is inadequate.

2 Hvac system having following loads

1. Supply and Exhaust blower motors rating are 55 kw X 2 and 30 Kw X 4 numbers.

2. air condition load is of 20Kw X 2 nos and

3. heating load of around 20 KW X 2 set