# Maximum current carrying capacity of Bus Bar

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1. Nov 22, 2015

### muet

If I have to transfer 250 MWh through 3 phase aluminium tubular busbar what is the maximum current carrying capacity under normal condition at 80c temperature and voltage is 132kv at busbar from each 60mw 04 transformers 50hz 132/11kv stepup transformers connected on that busbar,

this is not academic, i need to calculate bus bar current and 72M length which is fixed and i need wall thickness and inner and outer dia ?

thanks

2. Nov 22, 2015

### anorlunda

3. Nov 22, 2015

### muet

thanks anorlunda,yes i searched entire internet. and i found them. But. Problem is that. I am confused that my power which is to transfer and length 72m can suport that and my voltage and friquency and we have to connect 04 Stepup transformers.,selected bus bar will compatible with that much power and current ?

Last edited: Nov 22, 2015
4. Nov 22, 2015

### anorlunda

Don't you mean MW, not MWh?

I don't understand that phrase.

Voltage and frequency don't matter, only amps and temperature. For example, you can transfer up to 199 amps, with a 65 degree C temperature rise, using 1/16 inch (1.6 mm) thick, 1/2 inch (13 mm) diameter bus bar. The table in the link provided gives similar answers for many ampere ratings.

5. Nov 22, 2015

### muet

.
we have 60MVA 04
Transformers which are going to connect. And we have to transfer almost 250 MW power at 132kv voltage ? Busbar
have to carry this much power all the time .

6. Nov 22, 2015

### anorlunda

Can you calculate the current from that data? If yes, what more do you need?

7. Nov 22, 2015

### muet

ok. I can calculate 250 MW at 132kv current. But i want to know. That bus bars are come in small sections which are going to connect and formed one 72m bare per phase. So all small bars have to carry that much current or combine of them say 72m single bar. ?

Last edited: Nov 22, 2015
8. Nov 22, 2015

### anorlunda

It is safest to assume they ask carry the same current. Don't forget possible overloads our future expansions.

Since bus bars are not expensive, it might be smart to buy some rated two times the amount you calculate.

9. Nov 22, 2015

### muet

thanks man . but i am still confused. that my bus bar total length is 72 m / phase and they might come in 12m small parts 6 parts per phase. are they have to carry that much current individually or combine of them ?,

10. Nov 22, 2015

### anorlunda

The current capacity is amps per meter to give a constant temperature rise.

The total length, and the number of short pieces doesn't matter.

11. Nov 22, 2015

### muet

means i have 12 m bar and 72m bar both have same rise of temperature at same current carrying ?

12. Nov 26, 2015

### muet

thanks anorlunda for informative conversation . we are gating 12m Bus bars total length of 72m per phase, and Dia is 80mm and wall thikness 8mm which will be carry upto 2500 A current at 85c temp ,

13. Nov 28, 2015