×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Contact US

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!

*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

Angle Suspension or Strain Arrangement?

Angle Suspension or Strain Arrangement?

RE: Angle Suspension or Strain Arrangement?

Why do you propose converting to a strain arrangement? Using deadend insulators will increase the loading on the tower under most loading situations. If the drop to the substation is a short span with a large elevation change, the differential tension could be substantial under extreme conductor temperatures.

Structural analysis doesn't necessarily mean a full blown computerized PLS-Tower model. You may be able to demonstrate that the new loads are less than the original design loads using a simple paper & pencil loading diagram. It would be irresponsible to reconfigure a transmission tower without a reasonable level of structural analysis.

RE: Angle Suspension or Strain Arrangement?

I agree with bacon4life. If the substation deadend does not require some other tension than what is out there now, I see no need in deadending the new alignment. It will cause more loading issues and should be analyzed structurally then.

If you are simply re-aligning the conductors (i.e. no new conductor installed), you should see lower loadings than the current configuration. The only question I would have is if you have enough clearance to the tower with the new alignment...

RE: Angle Suspension or Strain Arrangement?

(OP)
Thank you bacon4life and bhyde for the responses.

I was thinking of line/substation reliability and the structure design philosophy. If this tower or any of its components experienced a failure then it could affect the substation taking it out of service. I thought having a strain structure if required with guy wires to balance longitudinal tension from line side. Guying will put additional vertical loads on cross-arms requiring strengthening, however it will increase reliability of the line. Do you guys agree with my thoughts?

I agree structural analysis doesn't have to be PLS-Tower analysis. A simple head load check is good. Structure loads with re-configured suspension arrangement will be less than the existing suspension arrangement due to reduced line angle and no change in conductor tension.
I was trying to ask the line reliability issue above if it can be explained in few words to the client.

Clearances are not a problem with re-configured suspension arrangement.

Thank you.

RE: Angle Suspension or Strain Arrangement?

Guy wires attached typical lattice towers are unlikely to work well. In order for a guy wire to pick up much load, the attachment point has to deflect a significant distance. The deflection in an unguyed lattice tower under full design load is going to be less than a few inches. The deflection in an unguyed wood or steel pole under full design load could easily be a couple of feet. The tension in a guy wire attached to a lattice tower will probably depend more on ambient temperature than on the structural loading of the tower. (Note that guyed lattice towers do exist, but they are a completely different design. They have a pivot point at the bottom to allow the entire tower to deflect or rotate under load).

If the tower under consideration experiences a failure, I don't see how the insulator attachment type will protect the substation equipment. If you are referring to failures further down the transmission line cascading towards you substation, reframing it as a deadend won't help unless you specifically design it as a weak link. Only if the tower were actually a full tension deadend could it measurable improve reliability. However, since this seems to be a tangent tower, reframing as a deadend would not add reliability. I think the deadend hardware and splices would actually result in a marginally less reliable configuration.

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! Already a Member? Login


Resources

Low-Volume Rapid Injection Molding With 3D Printed Molds
Learn methods and guidelines for using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs and lead time. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Download Now
Design for Additive Manufacturing (DfAM)
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a part’s function at the center of their design considerations. Download Now
Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close