When Hurricane Maria swept through Puerto Rico, the results were devastating. In addition to the human tragedy, a large part of the country’s power transmission infrastructure was destroyed. Restoring the critical electrical transmission and distribution system meant installing new lines in often inhospitable and humid conditions. When the electrical construction contractor in the country ran into problems with their pulling lines, T&E Flow Services approached Houston-based Precision Tension to quickly provide an alternative pulling rope solution.
Precision Tension, which works with customers to determine what they need and provide effective solutions, recommended the Phillystran Ultra 12 Dyneema pulling line. The customer was skeptical at first, notes Andrew Clancy of Precision Tension.
“After their experience with the previous pulling line arching, they wanted to avoid the safety hazard and further loss of time during pulling operations," Clancy says. "Once we were able to show that Ultra 12 is made from Dyneema, a high modulus polyethylene with very low conductive properties compared with polyester coated pulling lines, we were clear to go ahead with the project.”
Rope strength and reliability are critical during the installation of transmission lines. Ultra 12 is a 12 strand rope that provides size-for-size the maximum strength-to-weight ratio. A one-inch diameter Ultra 12 rope has a real breaking force of 100,000 pounds. The torque-free Ultra 12 ropes provide flexural fatigue and bend-over-sheave performance. They are easy to handle in the field and quick to re-terminate by the transmission line installation crew in the event of a line failure, which often happens in this type of application.
Time was of the essence. Four reels carrying 22,000 ft of Ultra 12 were needed. Phillystran manufactured the pulling lines within four weeks and they were on site within five weeks of the contract being placed. Phillystran ropes are characterized by their ease of handling and inspection. Although the standard Ultra 12 is colored green, for installation of transmission lines, the pulling line ropes were manufactured in red, yellow, blue, green; this allowed ropes and wires to be easily identified during line installation. The use of rope color is an important safety benefit of using Phillystran pulling lines as it ensures line visibility, even after heavy use.
A single four drum puller used the Ultra 12 pulling line rope. The Ultra 12 reels were wound onto the puller vehicle winches and the wire connected to the pulling line. The smaller diameter Ultra 12 ropes allowed more pulling rope on the winch than usual.
Clancy attended the transmission line installation and gave the crew training in splicing, which can be done in 15 minutes should the need arise. The Ultra 12 rope was supplied with eye terminations at each end.
“Ultra 12 is far easier to splice than many other pulling lines,” Clancy says. “For termination on-site, the Ultra 12 can be easily spliced in the field by performing a quick brummel splice, avoiding the need for time-consuming and complicated splices and terminations you find with other pulling lines.”
Installation of 22,000 ft transmission cable was completed in less than 24 hours using the Phillystran Ultra 12 pulling lines.
“A part of what Precision Tension does is supply great products with technical / field support both on the front end and back end of an order," Clancy says. "The project went very smoothly thanks to Phillystran’s manufacturing capability ensuring quick delivery. And secondly, the ease of using Ultra 12, and the pulling crew’s expertise, meant the installation was quick and efficient. The pulling line crew liked it and would use Ultra 12 again.”
For more information on Phillystran pulling lines visit www.phillystran.com.