Answer / ashish patel

My dear friends,

First of all i want to introduce myself as transformer engr
having 12 years of experience in transformer field. Now in
reply of your question, if u r asking about Name Plate of
transformer, VA = 1.732 * V * Amp
Suppose In Name Plate,
HV Volts mentioned 11000 V, HV rated current mentioned 5.25
Amp, Than Transformer capacity is
1.732 * 11000 * 5.25 = 100023 VA = 100 KVA.

In the same name plate,
LV Volts mentioned 433 V, LV rated current mentioned 133.34
Amp, So Transformer capacity is
1.732 * 433 * 133.34 = 99999 VA = 100 KVA.


If you are asking about to decide transformer capacity, u
hv to calculate your total load + future expansion load.
Than you can take decision about ur required transformer
capacity.

Answer / satya

the kva rating can be determined using the formula
kva=power supplied(in KW)/power factor.
so if the transformer is feeding a load of 100MW industrial
load. then the KVA rating of transformer to be used has to be
100/.85=117.647mva
we haver assumed the power factor for industrial load to be .85

Answer / m.ulaganathan

the kva of an transformer also depends on form factors.
the usage of kva 11,33,66kva all depends on form factor
as 1.11.

Answer / ddbtechee

First Calculate Kw Load of the plant or system which is connected to that transformer.Load is not directly calculated but calculated accordingly as per plant requirement like Continuous,Intermittent & Standby. After calculating the total load of the System in Kw.For calculate KVA of the transformer we use the Formula
KVA Load of the Tranformer - Total Plant Load Connected to transformer ( In Kw) / Power Factor

For Easy calculation ,we take PF value as 0.8.

Answer / saravanakumar

This is the formulae for that, KVA=KW/P.F (At the time of
load calculations we should considered the power factor is
0.8 only.)

Answer / mallikarjuna

it is very simple by knowing the formula is kva=kw/pf then
applying the formula where kw=1oo thne pf is normaly is
0.85
therefore kva=100/0.85
117.647M VA

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