×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Unbelievable

Unbelievable

Unbelievable

(OP)
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?

RE: Unbelievable

(OP)
Sorry, that should have been 2.3555 short circuit GVA

RE: Unbelievable

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.

----------------------------------

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

RE: Unbelievable


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

RE: Unbelievable

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.

RE: Unbelievable

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

RE: Unbelievable

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

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources