The TATA Power Co., Ltd., India’s oldest and largest private-sector electric utility, has chosen 3M Aluminum Conductor Composite Reinforced (3M ACCR) to substantially increase electricity transmission capacity on their 110-kV Borivali-Malad and Salsette-Saki transmission lines near Mumbai.
The 3M conductor is being installed in place of existing ACSR conductors, without the need to construct new transmission towers, as the right of way available was inadequate. The innovative lightweight, sag-resistant overhead conductor can carry twice the amount of electricity compared with conventional steel conductors of the same diameter.
This deployment adds India to the growing list of countries in which 3M ACCR is being used to boost transmission capacity in either densely developed or environmentally sensitive areas. The conductor allows major capacity increases while avoiding the costs and disruptive effects of tower construction or acquiring additional rights of way. Some of the other countries in which 3M ACCR is in use are the U.S., Canada, Brazil and the People’s Republic of China.
TATA Power Co., part of the India-based worldwide TATA industrial conglomerate, is headquartered in Mumbai, the capital of Maharashtra state. The utility has installed generation capacity of 2,323 megawatts.
Formerly known as Bombay, the city of Mumbai occupies a peninsula on India’s west coast. The city and its environs make up one of the world’s most densely developed metropolitan areas, with a population of nearly 12 million. The above two transmission lines serve growing areas to the north of Mumbai.
“The lines linking these substations were upgraded a few years ago, going from a single to a bundled ACSR, but that upgrade has not kept pace with the growth in demand,” explains Tim Koenig, director of the 3M High Capacity Conductor Program. “The installation of two double-circuit 110-kV lines using lightweight 3M ACCR will provide a cost-effective long-term solution with minimal disruptive impact on the communities.”
The Borivali-Malad and Salsette-Saki line upgrades will require a total of 200 km (125 mi) of conductor to cover circuits of 8 km of each line, making this the largest single application of 3M ACCR to date. Installation of the Borivali-Malad circuits is complete. Installation on Salsette-Saki is planned in the near future.
Located on the Arabian Sea, between the Tropic of Cancer and the Equator, Mumbai is subject to both extreme heat and heavy monsoons. Koenig notes that 3M ACCR has been in use in continuous field tests and commercial operation for nearly a decade, under a wide range of harsh climate conditions, meeting all performance and reliability expectations with no failures in the field, in either installation or operation.
“It’s a proven, high-performance conductor that can match the sag and tension of the existing conductor with less weight while doubling capacity on the line,” he says. “And because it’s installed on existing towers, utilities can reduce the costs and risks associated with transmission construction projects, without adding any risk to the existing system.”
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.
More information about the 3M high capacity conductor is available at www.3M.com/accr.