Calculating load and no load losses of cables 4

[LSpark]

How do you calculate the load and no load losses of a cable in kW please? I'm used to dealing with these for transformers but it doesn't seem to be as straight forward for cables. Thanks!

 

[jghrist]

I agree that the SI units are preferable, but the Brugg Cable Guide formula results in values that are different from the Prysmian formula by a factor of 100.

Another source (Rating of Electric Power Cables, George J. Anders, IEEE Press, 1997) uses the formula
C=e·10^-9/[18·ln(D/d)] where C is in F/m.
This formula gives results the same as the Prysmian formula when converted to the same units.

Using and example from Anders, 400 kV PPL cable with D=94.6 mm, d=58.6 mm, f=60 Hz, e=2.8, tan(delta)= 0.001 gives

C=0.325 uF/km with Anders and Prysmian
C=32.5 mF/km with Brugg

W=6.53 kW/km with Anders
W=6.50 kW/km with Prysmian
W=654 kW/km with Brugg

 

[Marmite]

Attached is an extract from the BICC cables handbook. Equation 2.12.
Regards
Marmite

 

[LSpark]

Thanks Marmite, it's a BICC cable not that it should affect the theory.

I've saved all the links so I can bring myself up to speed on cables, we're about to split my group at work in half and I think our cable guy will end up in the other group so it's no bad thing if I branch out a bit.

 

[southside111]

To follow up on this thread, I have a question.

For three phase cable/conductor, is the right simple equation to use to calculate losses:

P = i^2R

OR

P = 3 * i^2R

Thanks!