Here is the situation:

It is a municipal system, very rural, and has long single phase runs with low fault current. For example: 2400 delta single phase lateral ends up with about 92A fault current at the end of the run. The run is 7.5 miles with AAAC Ames and a 40K fuse on the txf secondary. The only fusing is on the secondary side of a stepdown transformer (13.2kv primary). Trying to use ArcPro and the fault current is too low (<200A lower limit). IEEE 1584 is for 3 phase faults but did try it and got an absurd value.

Any ideas on how to figure the incident energy? READ MORE