How to calculate short circuit current rating in transformer || Fault level calculation

How to Calculate Short-Circuit Current:

First we must know these three values-
X-mer Rating = ?
Secondary Voltage = ?
% of Impedance = ?

Example:
X-mer Rating- 1500 KVA
Secondary Voltage- 480 V
% Impedance- 5.75%

Answer:
Formula:- (a) Isc = FLA / % Z Impedance
(b) FLA= KVA / (√3)×(kVsec)

Put the value in this formula
FLA= 1500 / (√3)×(.480)
FLA= 1,804 Amps

Put value of FLA in Isc formula-
Isc = 1804*100
5.75
Isc = 31373.91 amps

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[jkj]

NICE EXPLANATION SO FAR IN U TUBE THANK YOU SO MUCH

[parvezbamne]

Good and simple
Can u explain how to calculate no. Of earthing pit (station) for a given soil resistivity.
Thanks

[davem]

Great basic video for someone like me. Our plant has a pad mount transformer I can calculate using this.

[bbe-belajarbersamaedward]

Is it SC between phase to phase? What about phase to Neutral?

[karbonphiber]

What if the circuit breaker is on the primary side. Are you supposed to use the primary voltage instead of the secondary

[asanmasraf]

so based on this calculations we select MCCBs short circuit ratings?

[habtishasres]

very well with one question... do u mean percentage impedance the voltage impedance since there is no percentage impedance on name plate of transformer it's percentage voltage impedance?

[animishgodse]

Same kA rating we will use for breaker also or their is Another formula for Switchgear

[sivasankarp]

is this calculation same for three winding t/f because secondary side we have two windings .rating is changing for each winding then how can we caliculate

[sharad]

Actual value is always less than what you calculated because you have to add the cable impedence and also generator impedence which when added will limit your sc current but never the less this is a good approximation in sizing your breakers

[goaway]

Or you can just divide your nominal voltage by the circuit Ze.
Also the definition of PSCC is not what you said, either.
A short circuit is the unintentional interconnection of the live conductors & you don’t double it unless it’s 3 phase.

[Nirmalsingh-yyvn]

Hello bro how we can calculate voltage impedance of transformer if we know only h 220/66kv t/f of 160mva nd also short circuit current find

[fjdan]

In the last calculation Isc=1804*100, where did the 100 come from?

[sharad]

This applies if the short circuit happens at the transformer secondary terminals

[VinylChannel]

hey man, where you get the formula reference ? cz i can find anywhere

[vinothkannan]

What value is 100 at the last calculation

[mattt]

In your formula to find the FLA, would you always multiply the kVsec by the square root of 3 (e.i., 1.73...) even if this were a single-phase system? How would this formula differ?

[aligohar]

How to calculate short circuit current for motor?

[muruganmurugan-rqjj]

FLA =31373.91 AMP OR FLA = 31373.91 KA which is correct

[kalimkhan]

bhai formula conceptual nahi bataya aapne