Switchgear Short Circuit Fault Level
Switchgear Short Circuit Fault Level
(OP)
Hello All,
I am buying a 4.16 KV swgr fed by two incoming XFRM's rated 5 MVA, 27.6 kV/4.16 kV. Both will operate in parallel with no tie.
Voltage= 4.16 kV
TR1= 5 MVA %Z1= 5
TR2= 5 MVA %Z2=5
Short Circuit Contribution MVA(TR1)= 20 P.U.=13895 A
Short Circuit Contribution MVA(TR2)= 20 P.U.=13895 A
Total Contribution= 40 P.U.
S.C Contribution(Total from TR1 & TR2)= 27790 A
My switchgear is rated at 31.5 kVA rms symettrical. I just wanted a second opinion if I am missing anything in calculating maximum short circuit contribution towards 4.16 kV switchgear.
....
Appreciate your input !
I am buying a 4.16 KV swgr fed by two incoming XFRM's rated 5 MVA, 27.6 kV/4.16 kV. Both will operate in parallel with no tie.
Voltage= 4.16 kV
TR1= 5 MVA %Z1= 5
TR2= 5 MVA %Z2=5
Short Circuit Contribution MVA(TR1)= 20 P.U.=13895 A
Short Circuit Contribution MVA(TR2)= 20 P.U.=13895 A
Total Contribution= 40 P.U.
S.C Contribution(Total from TR1 & TR2)= 27790 A
My switchgear is rated at 31.5 kVA rms symettrical. I just wanted a second opinion if I am missing anything in calculating maximum short circuit contribution towards 4.16 kV switchgear.
....
Appreciate your input !






RE: Switchgear Short Circuit Fault Level
RE: Switchgear Short Circuit Fault Level
RE: Switchgear Short Circuit Fault Level
If it's actually 31.5 kA, refer to jghrist's response.
Also, you need to consider any motor contribution that may be coming from feeders connected to the switchgear. In a large facility, these cannot be ignored.
David Castor
www.cvoes.com