short circuit calculation

[mull982]

Hello

I had a question in regards to short circuit calculations I was hoping that someone could answer. Is the momentary fault current the same as assymetrical fault current, the fault current that occurs during the first half cycle of a fault. If they are not the same thing, then what is the difference between the two?

Thanks

Mull982

 

[davidr43229]

You are correct, however the fault is considered assymetrical up to the 3rd cycle of that fault, then it becomes symetrical (even on the top, even on the bottom) if the fault is allowed to continue.
http://www.bussmann.com/library/docs/Edp-1.pdf
Look on page 3, for a graphical representation.

Just my $.02