Voltage conditions @ 3ph bolted fault

[Defenestrator]

What happens to the voltage of a bus under the conditions of a 3 phase bolted fault? Does it go to zero? If so why?

 

[Jraef]

What happens to the voltage of a bus under the conditions of a 3 phase bolted fault? Does it go to zero? If so why?

All AC “goes to zero” twice per cycle. I think we need some context of your question to try to help you out here.

 

[Ingenieur]

depends on the stiffness of the supply
typically it will not go to 0, but experience a large drop/sag

if v = 480
and Z xfmr + sys Z is 0.02 Ohm (3 ph sec based)
and i fault = 10 kA at fault location (includes Z to fault)
it will drop to ~ 480 - (10,000 x 0.02) = 280 v

you will have a v drop of 280 along the conductors to the fault with 10 kA i
mostly resistive, 5 MW
the wires will melt unless interrupted
fault Z = 280/10000 z= 0.028

 

[Ingenieur]

if you are saying a fault across the bus
it will go to zero because athe total v drop will be upstream and thru the bars and at the fault v = 0

just as v goes to zero at the end of the conductors in the above example