When performing an arc flash calculation study do you use the normal condition fault current only or do you also look at alternate scenarios such as minimum or maximum fault current?
Joined: Sun Dec 23, 2007 1:44 pm Posts: 348 Location: Charlotte, NC
I voted that we consider alternate scenarios, but this is for (NESC) OH utility distribution lines where work will be performed at locations certainly other than the substation bus.
Joined: Thu Oct 18, 2007 7:10 pm Posts: 262 Location: NW USA
I have manipulated the local PUD substation power transformers on and off line (only within the software ) to affect highest and lowest available fault current. This did not affect most locations on this particular study buy perhaps a dozen out of 400 busses increased arc flash exposure when fault current was lowest.
Most locations I would not have access to information to do this but at this one spot I had previously completed work for the PUD.
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) to affect highest and lowest available fault current. This did not affect most locations on this particular study buy perhaps a dozen out of 400 busses increased arc flash exposure when fault current was lowest.