Using ETAP or SKM to model AF switchgear.

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Bugman1400

Senior Member
Location
Charlotte, NC
Can AF rated switchgear by SquareD or other swgr mfr be modeled in ETAP or SKM to where when the AF analysis is run a low IE shows up instead of a higher IE that would be seen with non-AF rated swgr?
 

Defenestrator

Member
Location
Denver, CO
Occupation
Electrical Engineer
Im not sure about that one, you definitely do have the choice to pick the type of gear represented by the bus though.

I would ask SKM support, call or send them an email. That is if you have a license with them. Theyve been really helpful to me when i have issues with the software.
 

wbdvt

Senior Member
Location
Rutland, VT, USA
Occupation
Electrical Engineer, PE
I don't believe how it is modeled will affect the value of incident energy at the switchgear. The purpose of arc rated switchgear is to protect the person from the arc by design. This includes a means to direct the flash away from the individual.
 

JoeStillman

Senior Member
Location
West Chester, PA
Not sure what you mean by AF-rated switchgear;

There's Arc-Resistant gear, as wbdvt describes. This gear doesn't affect the results of your AF study. Remember, you're quantifying the energy that's released, not where it goes or how likely that release is.

There's switchgear that uses breakers with "Maintenance-mode" settings. These are breakers where you toggle a switch that lowers the instantaneous setting of the breaker, reducing the burn-time for any AF downstream. For these, you need to run your study twice, once for operating-mode and once for maintenance-mode.

Finally, there's some tricky new gear that uses optical sensors to detect an arc. The photocells trip the mains and clear the fault. I don't know if ETAP or SKM include models of these, but I do know you can create your own model if you know the time-current characteristics.
 

Bugman1400

Senior Member
Location
Charlotte, NC
Thank you for the prompt and experienced replies. Luckily, I have both ETAP and SKM licenses. I also have not heard of modeling AF-resistant switchgear that would result in a lower IE but, the client did not like the initial IE levels from the study and wanted a response. I am also familiar with "Maintenance-mode" settings and using optical sensors in SEL 751A relays but, this just provides faster tripping times. I will also reach out to the makers of ETAP and SKM to see if this type of modeling is available.
 

wbdvt

Senior Member
Location
Rutland, VT, USA
Occupation
Electrical Engineer, PE
Thank you for the prompt and experienced replies. Luckily, I have both ETAP and SKM licenses. I also have not heard of modeling AF-resistant switchgear that would result in a lower IE but, the client did not like the initial IE levels from the study and wanted a response. I am also familiar with "Maintenance-mode" settings and using optical sensors in SEL 751A relays but, this just provides faster tripping times. I will also reach out to the makers of ETAP and SKM to see if this type of modeling is available.

So is it Arc Rated switchgear you are asking about? Can you define what AF means in this circumstance?

Again, the point is that the type of switchgear has no bearing on the incident energy seen at that switchgear. This is driven by system values and the upstream tripping device. Lowering the upstream tripping device time can reduce the incident energy. So "just provides faster tripping times" is what you want but you seem to be focused on the type of switchgear.
 
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