Arc Flash Studies and Electric Utility Company Short Circuit Data

Video is from the 16 Hour Arc Flash Class by Jim Phillips at brainfiller.co...
What do you do if the short circuit data is unavailable from the electric utility company? Can you use an “infinite source” calculation?
Many say an infinite source is not the worst case. Jim states that this is actually an incorrect statement - Watch Jim explain a work around using the infinite source when the utility company is not available.
How can short circuit current increase with time from the utility? Jim explains from his own experience earlier in his career, as the head of the Transmission Studies Group of a large electric utility why the current can increase. What X/R ratio would you assume (and what is an X/R ratio.
Learn the answer to these questions and more from this 13:38 minute video taken from Jim Phillips’ 16 hour class: How to Perform an Arc Flash Study - IEEE 1584. This class by Jim Phillips is scheduled as a live streaming/interactive class by several times a year and is also available on demand at our Online learning platform: brainfiller.co...
Notice: Although Jim Phillips, is the Vice Chair of IEEE 1584, International Chair of IEC TC78 Live Working Standards, Technical Committee Member of NFPA 70E and Member of the ASTM F18 Electrical Protective Equipment for Workers, the views in this video are those of Jim Phillips and may or may not represent views of any of the aforementioned standards.
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[@timfrey6087]

Can you show your work for the infinite bus calculation. I can not get the 31374 amps.

[@Brainfiller]

Sure thing.
SCA = short circuit amps (on secondary)
FLA2 = Full Load Amps (on secondary)
SCA = (FLA2 x 100) / %Z
FLA2 = 1500 kVA / [sqrt(3) x 0.48 kV] = 1804 Amps
SCA = [1804 Amps x 100] / 5.75
SCA = 31,374 Amps

[@timfrey6087]

Thank you