Wildfires can have devastating effects on electric utilities, with a single spark having the potential to ignite a dangerous blaze that can quickly spread and cause significant damage to the infrastructure or more importantly, the potential liability from loss of human life. The increased risk of wildfires caused by climate change has prompted many companies to shift from a reactive approach to a proactive one. Despite the challenges, new technologies and innovations are emerging that allow utilities to prevent wildfires from starting in the first place. One such approach involves insulating power lines, which can help reduce the risk of sparks that could ignite a wildfire, without the high cost of undergrounding.

Risks from Electric Cables Running Through Trees and Vegetation

Electricity and wildfires are a dangerous combination for utilities across the country. Despite efforts to safeguard transmission and distribution lines, power lines are increasingly being implicated as the source of some wildfires. When strong winds cause nearby trees and branches to fall into power lines or snap wooden poles, the resulting sparks can quickly turn into dangerous fires. With so many potential sources of ignition, utility companies face an ongoing challenge to keep power lines from sparking wildfires. The four common ways a power line can spark a fire include:

  1. Power lines falling: If a power line falls due to any reason, be it a tree fall or any other cause, it remains electrically charged until the power company switches it off. When the high-voltage conductor comes in contact with the vegetation on the ground, it may cause a fire.
  2. Power lines coming into contact with trees or vegetation: Even if a tree doesn’t collapse the power line, continual contact with the line can start a fire over time. Branches or foliage between two conductors can produce high-temperature electrical arcs that can create a spark.
  3. Conductor slap: While utility companies strategically place conductors so they do not touch each other, contact with conductors can happen during equipment failure. If conductors slap, they can produce hot metal particles that may ignite ground vegetation below the power lines.
  4. Failing equipment: As electrical equipment ages, it is more susceptible to failure. One of the most common outcomes of equipment failure is sparking that, if not replaced, can increase in intensity and spark a fire.

Fire Prevention AerialGuard Products

Especially during wildfire season, utility companies face severe criticism for overhead power lines. Therefore, utility companies constantly look for new technology to improve safety, mitigate fire threats, and upgrade their electric supply system. Reinforced fire-resistant cable has come a long way in recent years to reduce fire threats and safely withstand operation for a certain time in flame-burning conditions. Aerial Cable Systems are a reliable option for utilities in fire-prone areas.

Aerial Cable Systems have a basic structure of three separately run, covered conductors supported by a grounded messenger and held together by spacers, keeping the cables strategically positioned along the line. The supporting messenger protects the system from falling trees and limbs, and if poles or lines do fall, the covered conductor is less likely to spark a fire versus bare wire. Also, the small footprint of ASC reduces the amount and frequency of vegetation trimming along power lines. AerialGuard® is AWG’s aerial cable system that helps with fire mitigation and is used for overhead primary and secondary distribution systems.

AerialGuard® Cables: Tree Wire and Spacer Cables

AerialGuard® Cable is a track-resistant, 3-layer system used on tree wire and spacer cables. Overhead primary and secondary distribution systems rated 15 kV (nominal) use these aerial cables. If the wire comes in contact with trees or wildfire, the 3-layer system, consisting of a conductor shield and two covering layers, is designed to prevent short circuits and flashovers.

When appropriately installed, AerialGuard® Cable can effectively prevent system outages, damage, or fires that result from falling trees or branches. If used in tree wire systems, the line is installed in a flat configuration with a narrow right-of-way corridor. Self-supporting conductors, such as ACSR, are typical in this type of installation. When used in spacer cable power systems, the line is installed with uniform spacing in a diamond configuration maintained by spacer hardware. A bare messenger, such as ACSR, OPGW, bare aluminum clad steel, or galvanized steel wire, supports the spacer and cable assembly. Spacer cable assemblies require the narrowest right-of-way corridor, occupying minimal space.

AWG for Wildfire Risk Mitigation

Choosing insulated power lines equipped with flame-resistant technology is a cost-effective solution for reducing the risk of wildfires. At AWG, we offer AerialGuard® System Solutions including cable and hardware products, such as spacers, brackets, insulators and other hardware, used by utility companies nationwide. Contact us to learn more about using our AerialGuard® System Solution in your tree wire or spacer cable system.

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