How to know the VA rating of a transformer

Hello to all


I am an electrical engineer and in an interview I was asked to tell the MVA rating of a transformer of few KV , and nothing was given means neither the power factor and nor the current , so I want to ask you people is there any way to determine the MVA rating of the transformer from the KV or vice-versa.


Please tell me with an example if possible.



Thank you

asked 9/11/2011
piyush071
piyush07

3 Answers

Generally Transformers are designed as per the requirement of the consumer or demand factor, it all depends on the winding, loses and short circuit current, the main Loses of the transformer is copper loss ie,of the winding that is A (current) and core losses( iron loss/hysteresis)  are nothing but V (voltage) and now rating of the transformer are from 0.001 MVA  to 2500 MVA all depends upon the application, While generating Power the Voltage is generated to 11 KV and  then it is step up with Power transformer as per the demand, an the same power is transmitted by transmission line keep in view of voltage drop.

answered 8/10/2013 Sathya Narayana JE E/M 46
Sathya Narayana JE E/M
What is the maximum and minimum MVA ratings of following transformers used in transmission and distribution of power-

1 .66KV/11KV transformers                                                                                                                                      2.132KV/11KV Transformer

What is the criteria on which the manufacturers decides the MVA rating?

answered 7/6/2013 ram31 66
ram31
Not really. Choose any kV and look at a manufacturers catalogue and there will be a large range of MVA. The only thing you can probably say is that the bigger the kV, the larger that transformer as generally engineers will increase the voltage to transmit more power.

I'm reading a Siemens guide and they have typical ranges of 100 kVA to 30 MVA for what they call Small Power, 40 to 250 MVA for Medium Power and 200 to over 1000 MVA for Power Transformers.
answered 9/12/2011 Steven McFadyen 246
Steven McFadyen

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