HV cable
HV cable
(OP)
Hello everyone. I am new to the forum.
I would like to ask for help regarding HV cables.
I am sizing a cable for the secondary side of a transformer, 12MVA 4.16/138kV. I searched cable manufacturers catalogue for HV cable sizes (145kV) and found that the minimum size I can find is around 400-500mm2.
Is there a minimum size of cable that should be used for HV installation?
The current in the secondary side of the transformer is only 50.2A? Should I use 400m2 even with only 50.2A? (not taking voltage drop into consideration)
Thank you very much.
I would like to ask for help regarding HV cables.
I am sizing a cable for the secondary side of a transformer, 12MVA 4.16/138kV. I searched cable manufacturers catalogue for HV cable sizes (145kV) and found that the minimum size I can find is around 400-500mm2.
Is there a minimum size of cable that should be used for HV installation?
The current in the secondary side of the transformer is only 50.2A? Should I use 400m2 even with only 50.2A? (not taking voltage drop into consideration)
Thank you very much.






RE: HV cable
RE: HV cable
David - 240mm² is roughly 500kcmil. A 2:1 conversion ratio is near enough for rule-of-thumb work.
RE: HV cable
Once upon a time I could recite the base amperages of all sorts of AWG/kcmil sizes, but now none of that matter. NESC rules rather than NEC rules, and ratings are all in the realm of the planner, not the protection engineer; besides, the conductor size may not matter at all if something else is the limiting component of the the element.
That aside, the point remains that you probably won't find a 60A, 145kV cable. 240mm2 would be in the 400A ballpark previously mentioned if it's around 500kcmil.
RE: HV cable
I was worried that I might size the cable to big for the current it would carry. So is it is safe to say that for HV (138kV) installation the minimum size cable available would be around 240mm2 or 500kcmil?
Your help is very much appreciated.
RE: HV cable
did you check the cable size according to short circuit withstand ?
RE: HV cable
[link Kerite catalog]http://www.kerite.com/Portals/0/HighVoltage/MU038_...[/link] lists the minimum cable size for a variety of voltages, with their minimum at 138 kV of 500 kcmil @ 529 amps.