Composite or fiber reinforced polymer (FRP) materials have been used in the electrical utility grid since the 1960s. In the last 10 to 15 years, composite products have truly taken their place alongside the other engineered materials of steel and concrete as utilities look to increase infrastructure reliability with a shift away from wood poles and the uncertainties and liabilities associated with them.
The electrical power grid covers almost every corner of the earth and, as such, must endure many challenges including initial construction hurdles from topography and ground conditions through to in-service issues resulting in everything from extreme weather such as fire, hurricanes, and ice storms to everyday conditions like salt environments due to proximity to oceans or ice control on winter roads. Even woodpeckers and soil pH levels need to be considered in a hardened grid strategy.
Compared to the traditional materials like wood, steel and concrete used in overhead line construction, FRP composite components like poles and cross braces have unique and, when applied correctly, advantageous high-performance characteristics result in cost savings, resiliency, and safety, over the entire life cycle of the pole. Cost savings are accrued during transportation, installation, maintenance (or lack thereof) and storm restoration when compared to traditional grid materials. Other benefits also need to be quantified in relation to safety, environmental impact with no eco-toxicity, storm restoration, fire, and electrical resistance in a comprehensive grid strategy. Above all, the ability for accurate engineering and load calculations when designing with an engineered material, is paramount when resiliency and reliability are the cornerstones of the industry.
The best way to think of FRP composite poles and cross braces is for them to be another tool in the line designer’s toolbox to be used appropriately and according to the line construction and in-service conditions to achieve an optimized balance between reliability and the lowest lifecycle cost for grid infrastructure components.
There are four primary situations where composite poles should be utilized: