Unbelievable

[GOTWW]

Talking to a sales rep, He stated that the fault current in LA was getting up to 40KA @ 34kV, that is 1.36GW of fault current. I have a hard time even comprehending this. Are these numbers correct?

 

[GOTWW]

Sorry, that should have been 2.3555 short circuit GVA

 

[ScottyUK]

Hi GOTWW,

To put things in perspective, we have a peak assymetric fault level of 340kA at 16kV on our generator terminals.
40kA is certainly a healthy fault level, but not exceptionally so by European standards. I imagine that a city the size of LA must have some fairly substantial primary substations, and that fault levels close to these substations will be corrspondingly high unless deliberate steps have been taken to reduce the fault level.



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If we learn from our mistakes,
I'm getting a great education!

 

[busbar]

The time element should also be considered in fault energy… GVA·seconds, I guess? Hopefully, some high-speed differential relaying will work as planned.

 

[alehman]

That sounds like the utility is being conservative and providing you the highest possible fault current. That gives them the flexibility change their system if need be. 38kV vacuum circuit breakers are commonly available with symmetrical interrupating rating up to 40kA. Interesting coincidence. I'm sure the real value depends on where you are on the system.

 

[GOTWW]

Apparently, with the start-up of the new burbank power plant, the numbers are expected to go into the 60kA range.

 

[Modula2]

If it goes from 40KA to 60KA, would any existing customers be under rated?