Available Short Circuit Current

[PE-noy]

Utility Co. typically provides us with the 3-phase bolted fault available at the service point. For a grounded wye system (assuming balanced load on all three phases), what's the multiplier to get the equivalent line-to-ground fault current?
I appreciate any input and all the information in this Forum. Thank you all!

 

[davidr43229]

try this link:
http://www.cooperbussmann.com/7/SoftwarePrograms.html
and click software.
If the utility gave you the available, why do you want the line to ground fault?

 

[bob]

At the main switch the 3 phase fault and a line to gnd fault will be about the same value.

 

[brian senske]

availabe fault current

availabe fault current

Does any one know the formula for short cicuit calculations/available short circuit calculations. I was taking a test and I had a few "available fault current" questons that didnt work with my formulas from my uglys or my firms fast finder. The formulas that I have require you to plug in the number of conductors and the length of the conductors, the questoin from the test didnt give me that information. any information would be appreciated, thanks vey much.

 

[Pierre C Belarge]

Does any one know the formula for short cicuit calculations/available short circuit calculations. I was taking a test and I had a few "available fault current" questons that didnt work with my formulas from my uglys or my firms fast finder. The formulas that I have require you to plug in the number of conductors and the length of the conductors, the questoin from the test didnt give me that information. any information would be appreciated, thanks vey much.

Brian
I am curious, how was the question worded?

 

[72.5kv]

Take a look through Mike Holts free documents. There is a pdf file that show step by step how to calculate worst case scenerio fault current levels. All factors are considered. eg conductor lenght, number runs, and transformer worst case impedence.