Oh, and for anyone using PLS-CADD lately, it seems at least one of the Southwire PLS wir files on the PLS website had an incorrect value for the RBS of the conductor (by a few thousand pounds!).
This is useful to us as we have some cases where we design the tower for 1" ice, but the sag clearances for less than that.)Īlso, read this article - it has some good points to read about creep vs load. For your own peace of mind, be VERY aware about how it calculates load and creep - it automatically takes the heaviest load case to be the one causing 'final after load', (compared to PLS-CADD where you can choose which is your 'load' case. Last I checked (which admittedly was over a year ago, Southwire Sag10 still had some known bugs that they had NOT fixed. GVH uses PLS-CADD on a transmission or distribution projects from start to end, including importing survey data, criteria development, structure, design, conductor sagging and Plan & Profile drawing development and plotting. If you are doing plain sagtension calculations, I'd personally suggest against Southwire Sag10, and recommend PLS-CADD Lite. PLS-CADD is the industry standard in overhead line design and drafting software. It uses the same conductor coefficients as Southwire Sag10, so if used properly, they should give the same result. SAG10 now by Southwire and formerly sold by ALCOA is the standard for sag and tension calculations where regular creep and elevated temperature creep is considered. It is common, however, for lower unloaded tension limits to be used. I've been using it for 3 years as part of a large utility, and it's fairly easy to learn. If you are in the T-Line business your company should consider PLS-CADD which is probably used by the majority of companies in the industry. The tension limits are: 60 under maximum ice and wind load, 33.3 initial unloaded (when installed) at 60☏, and 25 final unloaded (after maximum loading has occurred) at 60☏. It has also been observed that this aspect of line design needs to be expounded to many users. This is because cable tensions have a profound impact upon the cost, reliability and safety of a line.
I have used both Alcoa (now Southwire) Sag10, as well as PLS-CADD.įor the design of a full transmission line (from line routing, to prelim and detailed design, to checking and making quick field changes), PLS-CADD is supreme. 1 Cable Tensions in PLS-CADD By: Greg Chapman Ergon Energy, Australia It is important to understand the rationale behind PLS-CADD when it comes to cable tensions.