Chongqing Electric Power Corp. has become the second major utility in the People’s Republic of China to install the 3M Aluminum Conductor Composite Reinforced (3M ACCR) to boost transmission capacity on a key line without the need to build larger transmission towers. The utility says it needed extra capacity to meet anticipated heavy power demand for the summer Olympics in Beijing and did not have time to construct new towers.
This installation will serve more than a half-million residents within two districts in Chongqing City, an ancient city with a population of approximately four million, located on the Yangtze River in southwest China, within Sichuan Province.
In late 2007, Shanghai Electric became the first utility outside of the United States to install the 3M ACCR. Since then, utilities in Canada and Brazil also have chosen 3M’s conductor to enlarge capacity on lines where new construction would pose economic or environmental problems. Fourteen utilities in the United States so far have deployed 3M ACCR, which can carry more than twice the power of conventional steel conductors of the same diameter.
Using existing towers, Chongqing Electric has installed a two-circuit line of approximately 3.4 miles (5.5 km), linking the Shuinian and Shuangshan substations. Chongqing is in a subtropical region with high humidity and frequently extreme summer heat, and 3M ACCR was chosen in part because of its proven reliability in difficult climates.
“This is one of the hottest cities of China, with monsoonal weather, and we required a conductor that could be relied upon to carry more current under those conditions, and could be installed quickly and reliably within the existing infrastructure,” said Wang Xinkuan, chief design engineer for Chongqing Electric Power. Installation required only two weeks.
3M ACCR’s low sag, strength and durability result from its core, which is composed of aluminum oxide (alumina) fibers embedded in high-purity aluminum. The constituent materials are chemically compatible with each other and can withstand high temperatures without adverse chemical reactions or any appreciable loss in strength. The conductor also is highly resistant to corrosion and has the durability typically associated with all-aluminum conductors.