×
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 connections
2

earthing connections

earthing connections

(OP)
hi again,
 can the earth grid from a windfarm be connected to the substation earthgrid (10 km away ) via the cable earth sheaths? the fault current at the substation is 10kA,
will the cable heat when a earthfault occurs? will the earth sheath handle 10 kA? the cable from the customer's windfarm is 20kv. each wind turbine is also interconnected via earth sheaths and then eventually connected to our substation.
thanks

RE: earthing connections

First a decision should be made if the cable sheath is grounded at one end, both ends or at multiple grounded points based in calculation and expected system performance.

In the event of ground fault, if both ends are grounded, current will flow in the cable sheath. Under normal conditions, circulating current may be expected causing reduction on the cable carrying current capacity.


 On the other hand, for one end grounded, current do not flow in the sheath but the voltage will rise to level that need to be checked.

RE: earthing connections

Normally, there should be an equipment grounding conductor running along with the underground cable in a modern installation. This would be sized a minimum of 50% of the phase conductors which is standard practice for over 600 volts. The cable shields would be connected 1 end only of connected at both ends.

One thing that you do NOT want on a modern system is for the earth or water mains to be serving as the sole equipment grounding conductor. I have seen what happens as far as step and tingle voltage that occur when a service neutral is open or an underground branch circuit fails and leaks electricity into the soil.

Mike Cole, mc5w@earthlink.net

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