Siberian electric grid upgraded with 3M cables

3M ACCR is a lightweight, low-sag, high-capacity conductor that can carry twice the current or more of conventional steel-core conductors of the same diameter, on existing towers

St. Paul, Minn., May 16, 2012 — Already in use on four continents in a broad range of harsh climates, 3M Aluminum Conductor Composite Reinforced (ACCR) has now been installed in Siberia, serving one of the region's largest cities, Irkutsk.

Irkutsk Electronetwork Co. chose the 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.

3M ACCR is a lightweight, low-sag, high-capacity conductor that 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 1,600 amperes on the link between a local hydropower plant and the Tzimlyanskaya substation, and to 1,240 amps on the Tzimlyanskaya-Kirovskaya substation link. The 3M 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.

Koenig adds that interest in 3M ACCR also is growing as a tool for helping to bring power from renewable energy sources onto the grid.

Irkutsk is a city of about 600,000 residents, in the Irkutsk Oblast (administrative district), about 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.

3M ACCR also is operating in installations by utilities in Moscow and several other Russian locations, as well as in China, India, Brazil, Canada, Western Europe and throughout the U.S.

3M ACCR was developed with the support of the U.S. Department of Energy and with early contributions by the Defense Advanced Research Projects Agency. 3M's innovation is the ACCR core, which 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.

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