Hydro One Proves Samson Synthetic Cordage Pulls More than its Weight
For more than 100 years, Hydro One has supplied power to Ontario, Canada. Today, it is one of North America's largest transmission and distribution companies with almost 30,000 km (18,600 miles) of transmission lines; 281 transmission stations; 1,015 distribution and regulating stations; and 1.3 million customers. Hydro One's mission is to deliver electricity to its consumers safely while managing their resources with excellence and innovation. That's why the company turned to Samson for solutions to a couple of its toughest jobs.
"Hydro One has historically used AmSteel® as a rigging line," says Jeff Pellar, Work Methods Specialist for Hydro One. "It has proven to be very durable and is a highly valued tool." Its earlier experiences with AmSteel®, a 12-strand single braid made with Dyneema® fiber, provided Hydro One with the confidence to explore purchasing long lengths of high-performance synthetic rope for use as pilot, intermediate, and bull lines for stringing conductors.
AmSteel® II Plus: A Cost-Saving and Efficient Solution
The first project Pellar had in mind was a typical job, calling for a helicopter to fly out a pilot line that would pull an intermediate line pulling the bull line, which would pull a two-conductor bundle with pulling tensions of up to 15,000 lbs. "Neither the existing pilot line nor the intermediate line had this much pulling capacity," says Pellar.
Two 30,000-ft lengths of 7/8" Samson AmSteel® II Plus, a lightweight, double braid made with a Dyneema® fiber core and a polyester cover, was selected to replace both the intermediate line and the bull line because of its superior strength-to-weight ratio, which increased the overall pulling capacity for the job. This meant that it was a safer pull, because AmSteel® II Plus relieved the weight burden by as much as 10 lbs. per 100 ft. of line compared with the intermediate line.
"By using AmSteel® II Plus we were able to remove two steps in the process. And we were able to use the AmSteel® II Plus with existing stringing equipment; no special handling or special equipment was necessary the way it is when a very heavy steel bull line is used." An added benefit for Hydro One is the ease of splicing AmSteel® II Plus compared with the other product, which Pellar says is "complex to splice and requires special training." Furthermore, Pellar concluded that "tangible cost savings were realized during the installation of conductors on this project due to reduced handling and better utilization of equipment."
AmSteel®: More than a Rigging Rope
Hydro One's second project called for 500 kV circuits in four-conductor bundles to be pulled simultaneously. This installation, again, called for the use of a pilot line, an intermediate line, and, with pulling tensions in excess of 20,000 lbs this time, a steel bull line.
Considering the sucess had with AmSteel® II Plus, Hydro One turned to Samson again, but chose to replace the pilot and intermediate lines with two 30,000-ft lengths of 5/8" AmSteel® - the same rope relied on for all their rigging.
"Its light weight and low elongation mean that AmSteel® as a pilot line was light enough for a helicopter to fly out and install the stringing blocks, but it was also strong enough to pull in the steel bull line attached to the conductor," explains Pellar. "The use of high-performance AmSteel® eliminated the need for the intermediate line, cutting one step out of the overall operation," demonstrating how Samson stringing lines can save money and streamline operations.