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shyamaprasad
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Join Date: Oct 2009
Posts: 1

Busbar Calculations

10/08/2009 1:06 PM

Min . cross sectional area required of busbar, depend upon short circuot current.

Ex. Short circuit current is -- 50KA

SHORT CIRCUIT DURATION :-- 1 SEC

final temp of busbarr in deg centrigate :-165deg.c

initial temp of busbar in deg.c : 65deg.c

cross sectional area of busbar how much??????

please give me a solution...
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Carl Pugh
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Join Date: Jun 2009
Posts: 134
Good Answers: 11
#1

Re: sFault level calculation for busbar to choose a cross sectional area.

10/08/2009 2:15 PM

Requires calculus to obtain exact solution, but approximate solution can be obtained as below.

Assume bus bar size and length.

Calculate resistance at some intermediate temperature.

Calculate watt-second (joule) loss.

Calculate weight of busbar.

Calculate temperature rise of busbar
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jack of all trades
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New Zealand - Member - Kiwi Popular Science - Weaponology - New Member Engineering Fields - Power Engineering - New Member Engineering Fields - Electrical Engineering - New Member

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Location: Auckland, New Zealand
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#2

Re: sFault level calculation for busbar to choose a cross sectional area.

10/08/2009 2:40 PM

The short rough answer is around 400mm2.

This is a VERY common question on CR4. See previous threads on CR4 for the theory and formulas on how to arrive at the final answer (don't just take my word for it).

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Tippycanoe
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Join Date: Feb 2009
Location: Halcottsville, NY
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#3
In reply to #2

Re: sFault level calculation for busbar to choose a cross sectional area.

10/08/2009 5:41 PM

You may need to factor in corona effects for a clean scope, where the minimal is not always optimal.

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Anonymous Poster
#5
In reply to #2

Re: sFault level calculation for busbar to choose a cross sectional area.

10/09/2009 4:30 AM

i agree with Jack of all trades suggest try ABB CAT DOC software available free from ABB for electrical calculations and you need to do some home work AtLeast on your part.

crm
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kvsridhar
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India - Member - New Member

Join Date: Sep 2009
Location: Temporarily at Ashburn, VA
Posts: 2744
Good Answers: 164
#4

Re: Busbar Calculations

10/09/2009 12:25 AM

have you tried the Busbar Calculator from L M Photonics? here is a link :

http://busbar32.software.informer.com/

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PWSlack
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United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

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Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain. Kettle's on.
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#6

Re: Busbar Calculations

10/09/2009 6:18 AM

Congratulations. A direct hit on CR4's most popular topic after cable sizing (to which the answer is British Standard 7671).

http://cr4.globalspec.com/search/sitesearch?do=show&sort=textmatchrank&srch=busbar%20sizing&srchobjs=t%2Cc&fs=12&order=asc

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pnaban
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Join Date: Jun 2010
Location: srilanka
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#7

Re: Busbar Calculations

08/11/2010 7:13 PM

You should contact a reputed busbar supplier.Books/cataloques might give guidelines but cannot be held responsible

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Anonymous Poster (1); Carl Pugh (1); jack of all trades (1); kvsridhar (1); pnaban (1); PWSlack (1); Tippycanoe (1)

Previous in Forum: How test the Buchholz relay during the maintenance of transformer   Next in Forum: HV Step Coil / Transformer for Electric Fence

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