Reduce Summer Storm Damage With Line Hardening
Major weather events are increasing in frequency and intensity, and as the power of storms increase so does the risk of significant losses. Distribution systems are not typically built to withstand hurricanes, severe summer storms, tropical storms, and superstorms, and a recent study concluded that the U.S. is not prepared for a catastrophic power outage, which can lead to serious consequences, including downtime, damaged equipment, lost data, and even deadly incidents.
Many utilities are taking a proactive approach by implementing line hardening before incurring damage. Line hardening not only helps mitigate damage, it also speeds up outage restoration, reduces the number of affected customers, and improves overall service reliability.
What can utilities do to implement line hardening?
There are several common-sense best practices that all utilities should implement:
- Establish and maintain a test-and-treat cycle for wood poles
- Conduct attachment audits and mitigate overloaded poles
- Institute regular feeder inspections
- Assess foreign-owned poles
- Develop standards for setting depths
- Conduct a loading assessment at installation and every time a new attachment is placed or discovered or the pole
For many areas of the country, however, more aggressive line hardening tactics are needed.
Why is ductile iron one of the most effective tactics?
Ductile iron was introduced in the 1960s as a modified version of cast iron, which has been used for hundreds of years for products dependent on strength and corrosion resistance. Ductile iron contains the same ingredients as cast iron, but with a different configuration of carbon. In cast iron, carbon is in flake form, while in ductile iron, the carbon is in nodular form. The result is that ductile iron has the ability to bend without breaking under intense load pressure, offering a more durable and reliable solution.
Ductile Iron Proves to Be the Key in Florida
In the Florida Keys, distribution is as difficult as you would expect, thanks to challenging geography, location, and weather. After the 2004 hurricane season, the Florida Keys Electric Cooperative (FKEC) needed to find a better pole solution. They had previously used concrete, wood, and steel poles. But steel corrodes, wood rots, and the weight of concrete makes transportation and installation expensive.
FKEC explored and tested as many options as possible. They needed something with the strength of concrete, but without the cost-prohibitive weight. They looked at fiberglass, but its extreme flexibility isn’t suited for the high winds in the Keys.
After a distributor mentioned that McWane manufactured ductile iron poles, an FKEC engineer experienced in metallurgy immediately understood the advantages. Ductile iron offers a superior combination of strength, light weight, durability, flexibility, and value. FKEC contacted a nearby company that had used ductile iron in its underground pipes since 1980. The company invited FKEC to take a look for themselves, and it was clear that ductile iron lasts a very long time.
While the initial purchase price of ductile iron is more than wood, installation is faster and easier and they require little-to-no maintenance, making it more cost-effective over the lifecycle of the poles. For FKEC, the choice was clear.
Mitigating Damage, Protecting Coastline Views
A high-end residential community on Texas’ Bolivar Peninsula presented an interesting challenge for Entergy Texas. The developer wanted a distribution solution that wouldn’t obstruct the coastline views. But because of the strong storms and high tides from the Gulf of Mexico, underground service wasn’t viable. They needed a solution that not only had curb appeal, but could also withstand storm surges.
After extensive research and consultation with other utilities, Entergy Texas found the perfect solution in ductile iron poles. Ductile iron was durable enough to survive hurricanes, and the coastline views were protected because the wires were hidden underground. And with a lifespan of 75 years, Entergy Texas knew it was the smartest investment they could make.