Composite Poles Stand Strong for Heartland Utility

Utilities have two priorities: keep the power on and stay on budget. But extreme storms regularly fight these priorities for Ameren Illinois and Ameren Missouri.

These two Heartland utility companies under Ameren Corporation share a single “Ameren way” of design, construction and safety standards. They also share the same challenges: both states suffer the same extreme weather conditions and have responded to these challenging circumstances with a solution that would help keep the lights on for Ameren customers.

Careful consideration and testing led both Ameren companies to TridentStrong Fiber Reinforced Polymer (FRP) utility poles. By staggering these poles among their wooden sub-transmission line infrastructure, Ameren has significantly decreased cascading losses, resulting in more reliable service and more satisfied customers.

Weather Woes

The Midwest may be spared from most hurricanes and earthquakes, but high-speed straight-line winds and tornadoes are regular events. Hit by winds exceeding 100 miles per hour, heartland utilities can lose scores of wood poles in a bad storm. Poles tip over, or in high enough winds, simply snap, taking the power lines down with them. This creates dangerous conditions near downed poles and wires, and a downed pole can create a “cascading” outage, as lines and poles are pulled down by other downed poles.

Cascading outages cost everyone dearly. Customers may be without power for days as line crews work as fast as safely possible to replace downed infrastructure. And during active storm conditions, the cost to repair or replace poles and lines can double or triple. Ameren wanted a solution to this no-win situation.

Wood Alternatives

Both Ameren utilities considered multiple alternatives to solve their cascading wood problem. Wood poles with steel reinforcements were tried, but, in high winds, they broke below ground since they weren’t driven down to below the butt of the pole. Steel seemed promising but was ruled out. Ameren places a high priority on worker safety, and adding a highly conductive steel pole in the energized zone was a potential safety issue that other materials avoided entirely. And the significant weight of steel was a further blocker.

Ameren also considered larger-diameter wood poles. Higher ANSI Class poles would be more resilient, but the utility industry is competing with many others to obtain these large-diameter poles. They’re more scarce and pricier, and they also require a significantly larger footprint, which is the amount of space needed to install the pole safely and effectively.

Composite poles by Trident Industries, a member of Creative Composites Group, emerged as the solution Ameren needed.

Infrastructural Resiliency

Ameren first purchased TridentStrong poles in 2010. Chosen due to their favorable footprint and performance characteristics relative to their diameter and height, the FRP poles brought Ameren’s infrastructural resiliency. They bend just the right amount in high winds, absorbing the impacts of the high winds and returning to their normal state without damage in most actual cases.

Ameren approached the composite integration practically: They spoke with their line crews and learned that a single crew can install four to five sub-transmission line poles during a storm in a working day. They also assessed historical outage data to identify the service locations most in danger of cascading and in need of grid hardening with composite poles.

With these benchmarks, Ameren began installing one FRP pole every fifth pole, with four wood poles in between, on sub-transmission lines in the areas most likely to suffer cascading outages. Ameren chose the single-layer FRP pole with a 14-inch diameter for poles 60 to 70 feet and 15 inches for poles over 75 feet. Ameren also uses TridentStrong multi-layer poles at corners, dead-ends and other unguyed locations where needed. The utilities hardened the grid in high-wind zones up to 20 miles in length, trusting the composite poles to stay standing even if storms pull down the wood poles.

It Worked

Tested by many powerful storms, Ameren’s technique proved extremely effective. The composite poles stayed standing, bending as needed to remain upright, even if the intervening wood poles leaned or came down. Outages were reduced to a handful of poles, allowing Ameren to restore power to customers in a few hours.

As seen in the photos, winds strong enough to snap wood poles during a terrible March storm in Missouri didn’t affect the FRP poles. And an ice storm that hit Illinois in January merely tipped the wood poles between the TridentStrong poles, a scenario that would’ve resulted in a cascading outage with just wood poles in place. The only composite poles that have broken so far have been hit directly by a tornado, which also flattened steel poles.

The resiliency of FRP poles installed in this configuration has allowed Ameren lines to withstand storm after storm, and the poles show no signs of deterioration even 10 years since installation. Their resiliency and long service life give composite poles an excellent total cost of ownership. A recent Life Cycle Cost Assessment shows that, although a single FRP pole has an initial cost three times greater than a single wood pole, there is no difference in total life cycle cost, due to FRP’s very long service life.

The TridentStrong pole design has made the installation and replacement process simpler for utilities. FRP has a high strength-to-weight ratio, and TridentStrong poles have a single profile from top to bottom, shipping in one piece. To aid line crews, CCG marks both the balance point and the ground line with removable tape, removing guesswork. TridentStrong poles have additional layers of simplicity and security: The poles come factory-predrilled, making them immediately ready for attachments like crossarms and transformers in the field. Ground wires are also factory-installed inside the pole, preventing possible copper theft and saving line crews from the time and expertise spent on ground wire installation.

Ameren places additional value on the relationship with Creative Composites Group (CCG). Every pole has a serial number linked to a traceability report that is tied to the purchase order, all to ensure quality throughout the life cycle. Ameren staff have visited TridentStrong manufacturing sites multiple times to personally confirm CCG’s outstanding quality control finding the site impressive and the CCG staff to be true partners.

Working in Segments

Ameren Illinois and Ameren Missouri have chosen to play the long game — and they’re winning. Customers are happier, power stays on more consistently and projects remain on budget. FRP poles have proved time and again that the staggered installation method is well worth the cost to buy in.