Arch Flash Hazard Analysis

[EricElec]

Hi there,

For those that are familiar with the arch flash hazard analysis using SKM, Easypower, etc,

Is it possible to perform the analysis on section of the one-line without the full one line modeled?

I would imagine you would need the equivalent impedance? Comments?

 

[DistCoop]

Yes, equivalent impedance would be required to get the three phase current at that location. You would need the protective device responsible for clearing a fault at that location modeled as well.

Also be aware that any motor or generator contribution would need to be considered in that equivalent impedance, and you'd need to take care that the protective device you model would actually clear the generator/motor fault contribution in reality.

 

[dpc]

Arc flash calculations require knowledge of the maximum 1/2 cycle fault current. If your model can calculate that accurately, you can determine the predicted arcing current. However, to determine the arc time, you would need to model the appropriate upstream device that will clear the fault, or tell the program what the arc duration will be.