impedence

You need some numbers bud

R equiv = R secondary + R Primary/ turns squared

X equiv = X secondary + X primary/ turns squared

Z equiv = Square root of R equiv^2 + X equiv^2

This is based on an Equivilant circuit with effects transferred to secondary side, good for use in per unit calculations to yield fault currents.

Hope this helps

Thank you for reply.

How do calculate fault current?

what are the parameters required for finding fault current?

please guide

Under three phase bolted fault:

1. Base Impedence = (rated line-to- neutral volts)/rated current

2. Per unit value = actual value Ω / base impedence

3. Per unit Isc = E (P.U)/Zs (P.U.)

4. Isc (A) = rated current x per unit Isc

You will need to calculate values in order to achieve the answer you need

Thank you.

How can get actual value Ω and E (P.U) ?

regards

srilakshmi

If you cannot figure out E (Voltage) and resistance of your feeder, then you need to find someone who can do this for you. I can give all the formulas in the world, but the basic stuff I have to assume you know.

Its time to find an EE who can do this calc.