Hi, I just discovered this forum and I was wandering if someone could help me with this problem that is driving me crazy.

I've been using the ETAP 12 version with the IEEE1584-2002 method for the arc flash analisis. I've reciently updated to ETAP 19 and started using the IEEE1584-2018 method, but i have a problem when simulating this particular config:

4 60HP motors attached to busbar 1, no motors or generators on busbar 2, and 2 differently rated generators on busbar 3 (see attached screenshot)



Busbar 1 and busbar 2 are phisically identical (same GAP, same WD, same everything), as they are part of the same switchboard. They can be linked together via CB3 or they can be linked through busbar 3

Important details: Gen2 (88kW) CB closes at 60sec when an arc flash happens and GEN1 (450kW) CB closes in just 0,08sec
[Substraction of Incident Energy for Multiple Source Systems is TRUE]
[Limit Maximum FCT: 2sec]
[Motor Contribution Based On: Motor Status]

When I simulate this I en up with the same Arc Current and FCT in both busbars but with a huge difference in the Incident Energy



This is clearly wrong because IE should be identical in both cases (there is no impedance between busbars), so its clearly an ETAP configuration problem.

If I disable the motors or disable GEN2 or lower the GEN2's CB opening time the problem gets solved, but in the current configuration I get this IE difference between busbars that i dont get with the IEEE1584-2002 method.

I suggest you present this dilemma to the ETAP tech support...they are usually very good at responding in a timely manner. Hope this helps.