An added benefit of using FRP over wood is that the composite pole will achieve the specific deflection requirement more consistently than wood. As Amol Vaidya, senior global innovation leader with Owens Corning, explains, “We are able to tailor the performance of those products to meet customer needs.”
Vaidya offers an example: “If the customer is looking for higher shear performance, that is typically driven by what we put on the glass in terms of chemistry [glass sizing]. This size drives the compatibility with the resin and can be customized.”
Lately, Vaidya has seen a trend toward reinforcements beyond typical ECR glass fibers to adjust the modulus of elasticity of composites. “Here, pultruded sections reinforced by high-modulus glass fibers or fabric composites enable a step change for composites performances,” he says.
In addition, polyurethane-based resin systems are emerging as a popular resin choice alongside polyester and vinyl ester resin systems. “We’re seeing this resin being used because of the benefits that material offers in terms of damage resistance as compared to other types of systems, including polyester and vinyl ester,” Vaidya says.
Ultimately, Haddad predicts, closer collaboration with the client could simplify the specification process for FRP utility poles. Currently, a specification may just note an ANSI-required pole tip circumference that’s largely irrelevant for FRP poles. “We’re hoping [in the future] they give us a groundline requirement and a deflection requirement in terms of inches per thousand pounds so that it’s truly an apples-to-apples comparison among the competitors that make composites distribution poles,” Haddad says.
Hurricane Grid Hardening
Of course, fires aren’t the only disaster that have led utility companies to consider grid hardening. In 2005, Hurricane Wilma damaged about 12,000 utility poles across Florida. Utilities in the state began moving some lines underground and switching to composite and concrete poles. Even so, more grid hardening is required as 2018’s Category 5 Hurricane Michael took out more than 6,800 utility poles in the Florida panhandle.
There’s ample evidence that FRP poles can stand up to high winds. RS Technologies installed about 500 poles in a 69kV transmission line in the Bahamas a decade ago. “That line took a direct hit from Category 4 Hurricane Matthew in 2016,” Fecht says. While Grand Bahama lost several thousand wood poles to the 140 mph winds, there was no damage to the composite structures, which were designed to withstand 150 mph winds.
Last year, RS Technologies was called in for a new project to support the island’s grid resiliency. The fabricator provided a small line of poles to connect a new solar farm and battery depot to Grand Bahama Power’s main substation. Shortly after completing that project, Hurricane Dorian devastated the island. Not only did the new project withstand the sustained 160 mph winds, but so did the initial 500-pole line.