[ARC FLASH] Multiplier factor for 3 phase arc-in-a-box in a 34.5 kV

[IgorIPC]

Hello everyone

I have been working on the calculation of the incident thermal energy in a 34.5 kV PV collector network and I got some problems when simulating the incident energy.
We are using PTW to carry out the analysis. Its default method is the IEEE 1584 for voltages below 15 kV and Ralph Lee's for voltages above 15 kV. As widely known, Ralph Lee's method is very conservative, leading us to energy levels that we are not able to protect.
PTW also has the option of applying NESC 2012 method, which seems better than Lee's method at this voltage level. However, the NESC table, also mentioned in OSHA, is valid for single-phase to ground fault in open-air, different from the site I am modeling here.

Searching for clarification I found many mentions to the multipliers that would transform the calculated NESC incident energy from single-phase open air to a three-phase in-a-box fault. However, I just found mentions and not actually references that show it up.

Thread238-370872 has, for example, the multipliers factors that, as described there, were obtained from OSHA, but I could not find it explicit. I would like to have a document containig these multipliers factors, which I could use as reference in my report. I suppose the ARCPRO manual provides them, as said in many papers, but none of them write its values.

I'd like to have a official document or techinical papper so I could use it as a reference.

Thanks.

 

[DistCoop]

You can find those multipliers in their manual, as you said. You can also find it in a paper they published called "ARCPRO 02.01 Technical Information." I hesitate to hand it out since they gave it to me along with purchasing the program, but you may ask these guys if you're allowed to have the paper.

http://www.kinectrics.com/Solutions/Pages/Arc-Hazard-Services.aspx