×
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

earthing system

earthing system

earthing system

(OP)
hi
how calculated rated power for
1- zagzag transformer with 10sec,30sec,1min,10min
2- NGR  with 10sec,30sec,1min,10min
3- reactance with 10sec,30sec,1min,10min
4-star-delta closed with 10sec,30sec,1min,10min
i need equation for calculated
this informaton is very importment
please and thanks

RE: earthing system

See:
IEEE 32/1972 "Neutral Grounding Devices"
or:
 Westinghouse "Electrical Transmission and Distribution Reference Book" published in 1964
ch.XI Grounding Transformers
But the maximum time rating is only 5 min.
Srated=Urated*K3*Irated
K3 from table 12 for time rated from 10 sec up to 5 min.
For NGR see [for instance]:
www.postglover.com/Literature/NG112-06_Tech_Info.pdf
www.postglover.com/neutralground.html
or Google "Neutral Grounding Devices"
 

RE: earthing system

(OP)
hi
how calculated rated for time
example if NGR=38 OHM for 10 sec  but i need calculated for value NGR if time 1min or 10 min

also if rated for transformer 100kvA FOR 10 SEC WHAT RATED for 1 min
i need how calculated or i need equation

RE: earthing system

You pretty much have to contact the manufacturer. A lot depends on when thermal equilibrium occurs, and that is strictly a function of the enclosure design.  

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