Power cable ampacity clarification

Thread Starter

powerloss

Joined Jan 2, 2014
1
Data: 66KV power cable, 3 phase, short circuit current 40KA, at a lod of 50 MVA.

Question 1. : In the cable sizing up process, is the cross section area meant for one cable feedng per phase or or all three pahses? Lets say the cable size come out to be 288 sq mm..does this represent a single cable (3 core+Earth) with total cross section area?

Question.2: What about the continuous current rating given in the catalogue? Will it be the total current carried for all three phases or each phase will carry that current to the load?

Thanks
 

Kermit2

Joined Feb 5, 2010
4,162
from the sparse data you provide I would surmise that the load was for the entire cable 3C+shield



for your other question well a GOOD catalogue should tell one those things now shouldn't it?
 

MaxHeadRoom

Joined Jul 18, 2013
28,684
Question 1. : In the cable sizing up process, is the cross section area meant for one cable feedng per phase or or all three pahses? Lets say the cable size come out to be 288 sq mm..does this represent a single cable (3 core+Earth) with total cross section area?
Cable size/current rating per conductor.
Max.
 

GopherT

Joined Nov 23, 2012
8,009
Data: 66KV power cable, 3 phase, short circuit current 40KA, at a lod of 50 MVA.

Question 1. : In the cable sizing up process, is the cross section area meant for one cable feedng per phase or or all three pahses? Lets say the cable size come out to be 288 sq mm..does this represent a single cable (3 core+Earth) with total cross section area?

Question.2: What about the continuous current rating given in the catalogue? Will it be the total current carried for all three phases or each phase will carry that current to the load?

Thanks

More things to think about...

Is it a delta system or Wye circuit? How will this impact the load seen by each cable?

Are you accounting for skin effect?
 
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