1-phase Short Circuit Calculation In Etap


Newly Registered
Dear Sir Ver,

Good day to all and especially to Sir Ver.

Sir, I need your help with regards to the above mention subject.

I am working here in saudi arabia as an electrical engineer (site).

It so happen that i visit our main opis, I saw the ETAP software used by our
Indian engineer in our opis for design.

Due to my curiosity, I take a look @ power grid editor-utility-Short Circuit (as per sample by etap)
in version 12.5. The primary voltage is 34.5kv.

SC Rating
MVAsc MVAsc X/R KAsc
3phase 1200 45 20.082

1-phase 1387.218 462.406 45 23.215
sqrt(3)Vll If Vln If

Sir, how you can compute the value of single phase short circuit in a given example.

I ask my indian fellow engineer but he is very much madamot?

Can u help me Sir?

Thanks and regards,

Nene Gu


Staff member
From your above example, the single short circuit is already given as 23.2 kA.

You can verify this from the given values under 1-phase:
$MVA_{SC}=1387.218~MVA$ - Singple phase short circuit MVA
$Voltage=34.5~kV$ - System voltage

To calculate single phase short circuit currrent:
$I_{SC}={MVA_{SC} \over {sqrt{3} \times KV}} $

$I_{SC}={1387.218 \over {sqrt{3} \times 34.5}} = 23.2148 kA$
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Newly Registered
Dear Sir Ver,

How about if all the data in single phase like MVAsc, X/R and single phase short circuit are not given?

How you can compute the single MVAsc, X/R and single phase short circuit current in the above example?

Thanks and regards.

Nene Gu