×
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

Lightning Protection - Rolling Sphere

Lightning Protection - Rolling Sphere

Lightning Protection - Rolling Sphere

(OP)
Gentlemen,
I have been trying to figure out a way to calculate a rolling sphere lightning protection radius for two different masts of unequal height having a distance smaller than the radius of the sphere.

I could go with the lower mast to be more conservative, but I would like to calculate the actual protection radius.

Also, I didn't see anything about this in IEEE standard and pretty much any paper that I have read so far.

Any advice or suggestion will be appreciated

Thanks

RE: Lightning Protection - Rolling Sphere

(OP)
Thanks. That's exactly what I was hoping for.

RE: Lightning Protection - Rolling Sphere

(OP)
I am trying to create a spreadsheet for rolling sphere.
You wouldn't happen to have one of those as well would you? Your first post was very helpful.
Thanks  

RE: Lightning Protection - Rolling Sphere

Sorry, I used Mathcad.  For two masts, a spreadsheet shouldn't be too difficult.  When you get to three unequal height masts, things get tricky.  You can take two masts at a time for the area outside the masts, but if the masts are far enough apart, the rolling sphere may intersect the equipment plane inside the three masts.  I had to use a Mathcad Solve Block.  See attached file.

RE: Lightning Protection - Rolling Sphere

(OP)
It's been a while since I worked on this. What I was actually looking for was a way to calculated the protection radius, if you have a shield wire with two different attachments of unequal heights.

RE: Lightning Protection - Rolling Sphere

You didn't mention the shield wire.  That's a whole different ballgame.  Now it's not a protection radius, but a protected area between two lines on either side of the shield wire.  I haven't quite worked out shield wires with different attachment heights.

How about two non-parallel shield wires with different attachement heights?  For grins, don't neglect sag.

RE: Lightning Protection - Rolling Sphere

(OP)
Like I mentioned earlier, I don't think I have seen anything in the standard, which talks about attachments of different heights.

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