Composite conductor

A high-temperature, low-sag overhead conductor from

, designed to help eliminate transmission bottlenecks that increasingly have plagued electricity grids in recent years causing brownouts and blackouts, is getting its first use in

.

Pacific Gas & Electric (PG&E) and a second utility in Southern California have installed 3M's Aluminium Conductor Composite Reinforced (ACCR) on short line segments near substations in Santa Clara and Oceanside, respectively. The Oceanside installation was funded, in part, by the California Energy Commission. The Electric Power Research Institute will monitor the line's performance. PG&E funded its own installation and is performing its own monitoring.

Three other major US utilities have installed, or announced plans to install, the new conductor on transmission lines in the West, Midwest and South.

Xcel Energy, a major utility, is already using the ACCR to relieve congestion on a 10-mile line in the Minneapolis-St. Paul region. In addition, the Western Area Power Administration recently said it will install the ACCR on a key 80-mile line in Arizona. The Alabama Power Company plans to install the new conductor on a critical 10-mile line in the eastern part of the state.

The ACCR is a new type of metal overhead line that contains a multi-strand core of heat-resistant, aluminium-matrix composite wires. The conductor retains its strength at high temperatures and is not adversely affected by environmental conditions. Its lightweight and reduced thermal expansion properties are what enable installation on existing towers, with no requirement for visual changes to a line or additional rights-of-way.

Prior to being commercialised, the ACCR underwent four years of field testing by several utilities, partially funded by the US Department of Energy.

More information about the 3M Composite Conductor is available at www.3m.com/accr.