11 kV Cable

I have a circuit in which the the transformer is of rating

 - 11kV / 415V, 50Hz, 1600kVA, Dyn11, 5% impedance connected to a 12kV, 50Hz ,630A indoor VCB with a 3cx70mm² 11kV cable.

The short circuit breaking current (AC RMS) rating of VCB is 31.5kA for 3 second.What should be the short current rating and time duration  of the 11kV cable ?


asked 12/23/2013
ram3166
ram31

1 Answer

http://www.engineering.schneider-electric.se/Attachments/ed/guide/06_determining_conductor_cross_sectional_areas.pdf

 

This link will be helpful for you. Page 544 is the right one for your question and equation is from IEC standard. Now, your question is a little bit unclear because time duration and current withstand capacity of cable are in direct proportion so usually u have to first take in consideration time for withstanding and than u will get current value and vise versa. Just read the document and if u have any question, don't hesitate to ask.

answered 12/23/2013 Mirko Lezajic 8
Mirko Lezajic

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