A2 Power System : Short Circuit Calculations

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[@itanongmokayengineer]

super clear explanation this helps me a lot thank you so much for sharing your brilliant mind

[@jaykesapalaran5434]

Thank you for sharing your knowledge ❤️ very much informative and easy to understand 💌 THANK YOU...

[@sambathbunkh]

Good explanation

[@sandipkumarprajapati3189]

Thank you Professor!

[@lythous]

Hi. I think you made a mistake in your calculations.
I_FB = (20000 / sqrt(3)) / 33.47
= 345 A @ 20kV :: 17.25 kA @ 400V

[@tomaszpiwowar7657]

You right!

[@atmsc4nd4l]

agree.

[@Brandlead]

605A at 110kV right not the primary of the 20kV,0.8MVA transformer?

[@shabeerahamed1501]

If we use cable which is connected to the transformers, we need to add those impedences in the SCC.

[@DebjitDas93]

In grid impedence calculation and Numerator in KV & denominator in MVA? How? If KV, then bring MVA into KVA

[@madhuvimal88]

Hai..
Can you please validate with etap value..
What inputs have taken in etap and that particular input how to use in manual calculation..

[@jfsimon1981]

Good day,
Is ths is mistake at 4'04" Isc,3P = (20000/1.732)/33.47 = 345 A (not 605A) ?
After calculating I found out different results:
Short circuit level at 20 kV: 605 A -> 345 A
Short circuit level at 400 V: 30 kA -> 17.25 kA
Thank you,
Jean-François

[@willgould4417]

I got the same result as you, think its a mistake

[@aymane9489]

Very good explanation, but I have a question. Since both of the grid's and the 110KV line's impedences are behind the transformator, why did you only multiply the line impedence in square of "the transformation ratio" but not the grid impedence. I meant by transformation ratio U2/U1. Thank you.

[@jfsimon1981]

Hi,
He calculated the grid impedence seen from 20 kV (20kV^2/4000MVA). Yes the units match in this case since kV^2=MVA.
Jean-François

[@arijitmahanta235]

I think there is calculation mistake during calculation of fault current at 20 kV side for fault at B.
It is coming 345 amps not 605 ams

[@mahmoud7142]

Thankfully for highclass explain

[@surendrakverma555]

Very good

[@atmsc4nd4l]

Fault current at bus B must be 17.25cis(-90)kA.

[@noobzgamer4358]

How if fault on bus 110kv before Transformator?

[@roufriaz1662]

Bts133 transistor replacement no

[@aymane9489]

You still didn't answer my question sir.