sag and tension design

[newkumone]

I have researched the forum and have been unable to find the answers I am looking for.

In doing this project I have chosen the initial design conditions, now I want to build a table to show the sag and tension changes based on the temperature changes. What is the formula for calculating sag/tension based on the temperature changes.

I noticed that STUJ had a design program he posted at the following location: castnet.dyndns.org/lview.htm I have tried to go there but this link seems to be down. Is there another location or does anyone else have it?

 

[jghrist]

I suggest using an industry accepted program such as Sag 10

http://www.acasolutions.com/products/software/sag10/index.html

but it isn't free. Using free programs downloaded from the internet without proper software verications can be hazardous.

If you can find the proper stress-strain curves and find a copy of Alcoa's "A.C.S.R. Graphic Method for Sag-Tension Calculations", you can calculate the tables yourself (no formula). This would be very time-consuming.

For a single design, you can probably get the conductor manufacturer to provide the tables.

 

[newkumone]

I am looking for the formulas that are used to build a spreadsheet. I do not want a software package that just spits out an answer, I want to understand how they derived the answer.

I have contacted a cable manufacturer and they did a preliminary report (based on the information that I provided) on SAG10. What they provided for sag and tension was close to what I had calculated for an initial stringing design condition for the messenger. The problem I have is once I have determined the initial design condition at the temperature I want how do I set up a stringing table for the remaining temperatures?

 

[Laplacian]

Electric Power Engineering Handbook by Grigsby has an informative section about the calculations. It also references a few other sources; IEEE Std 524-1993 and Transmission Line Catenary Calculations July 1935 AIEE Paper.

 

[bacon4life]

This RUS bullitin explains it.

http://www.usda.gov/rus/electric/pubs/1724e152.pdf