CLF and Arc Flash Studies

[Amex12]

What are your approaches to modelling transformer primary CLF fuses in arc flash studies? Currently, we do not consider them and I am not sure how to accurately model their affects in ETAP.

Thanks!

 

[davidbeach]

They probably don't matter. I would not expect a primary CLF to see enough current for a secondary fault to operate in the current limiting range.

I’ll see your silver lining and raise you two black clouds. - Protection Operations

 

[dpc]

You would just model their time-current curves like any other overcurrent device. Unless they are clearing within the first 1/2 cycle, they aren't considered current-limiting.