A three phase transformer has the following specs 300 KVA 440V. the impedance marked on the nameplate is 3.3% . Determine the available short circuit current at the secondary terminal of the transformer.
To determine the available short circuit current at the secondary terminal of the transformer, we can use the following formula:
Isc = (1 / Z) x Vfl
Where:
Isc = available short circuit current
Z = impedance (in decimal form)
Vfl = line-to-line voltage
First, we need to convert the impedance from percentage to a decimal form. The impedance in decimal form is 3.3 / 100 = 0.033.
Next, we need to convert the line-to-line voltage from 440V to line-to-neutral voltage. Since this is a three-phase transformer, the line-to-neutral voltage is Vfl / √3. So, Vfl = 440V / √3 = 253.27V.
Now, we can calculate the available short circuit current:
Isc = (1 / 0.033) x 253.27V
Isc = 7667.88V
Therefore, the available short circuit current at the secondary terminal of the transformer is approximately 7667.88V.