Question { 62121 }

How much current can 11KV line carry? What are the
formulae used to calculate current across both side of
transformer? Moreover I need to know can I connect 33KV
line with transformer of 1600KVA? Details are: V=415,
Pf= .9

Answer

Primary side voltage be 11KV,
Transformer's capacity= 1000KVA

Real power= Apparent*Power factor
KW=KVA*Power factor
if Power factor = 0.95
Power= 1000*0.95
Power=950KW
We also know,
Power(KW)=(root 3)*(KV)*I*Power factor
950=1.732*11*0.95*I
I(Current)= 49.7A

Secondary Voltage Be 433V
We know that,
Power(watts)=(root 3)*V*I*Power factor
Power=950KW=950000W
950000=1.732*433*I*0.95
I= 1333.4 A

Question { MNC, 4392 }

What is the power factor,apparent power,reactive power and
formula of power factor.

Answer

power factor= cos( R/Z)
Active power= V*I*cos(R/Z)
Apparent Power= V*I
Reactive power= V*I*sin(R/Z)