Irkutsk Electronetwork Co. in Siberia has installed new overhead conductor as a way to avoid tower construction or right-of-way expansion while nearly doubling power transmission to the city’s central district, where growing demand was putting a severe strain on capacity, according to the utility.

The lightweight, low-sag, high-capacity conductor from 3M, can carry twice the current or more of conventional steel-core conductors of the same diameter, on existing towers, thereby helping utilities circumvent problems in crowded urban settings and environmentally sensitive areas. Its low-sag characteristic also provides a solution for clearance issues.

In Irkutsk, the 110 kV line raises capacity to 1600 amperes on the link between a local hydropower plant and the Tzimlyanskaya substation, and to 1240 amps on the Tzimlyanskaya-Kirovskaya substation link. The ACCR line replaced conventional steel-aluminum conductors.

The utility considered the option of increasing capacity by building a parallel line, but determined that acquiring the land and constructing the towers would be prohibitively expensive and difficult because of the crowded urban area. Installing larger aluminum-steel conductors would have required rebuilding the existing towers to bear the heavier weight.

Irkutsk is a city of about 600,000 residents, in the Irkutsk Oblast (administrative district), approximately 2,600 miles east of Moscow. Its midwinter average daily mean temperature is about 0 degrees Fahrenheit (minus 18 Centigrade). The city plays an important role in aircraft manufacturing and metals smelting.

The ACCR core is composed of aluminum oxide (alumina) fibers embedded in high-purity aluminum utilizing a highly specialized and proprietary process. The result is a lightweight, low-sag, high-capacity conductor that can carry up to twice the current of conventional steel-core conductors of the same diameter on existing towers, thereby helping utilities upgrade transmission lines while avoiding a wide range of problems in a variety of applications. It has the durability and longevity of traditional steel core conductors, even after decades of continuous operation at temperatures as high as 210 degrees Celsius (410° F) and in emergency conditions at 240 degrees Celsius (464° F). The conductor’s performance has been demonstrated during testing at the U.S. Department of Energy’s Oak Ridge National Laboratory in Tennessee and in more than a decade of successful U.S. and international installations.