AECC Uses 3M™ ACCR to Complete Challenging Upgrades
Arkansas Electric Cooperative Corp. is the latest rural electric co-op to install ACCR.
AECC installed 3M™ ACCR on a section of the 161 kV Fitzhugh-SPA transmission line that crosses the Arkansas River.
In 1963, Arkansas Electric Cooperative Corporation (AECC) completed the Thomas B. Fitzhugh Generating Station at Ozark. At the time, the plant, the first built by a co-op in Arkansas, provided 50 MW's of natural gas and oil based electricity generation. In 2003, it was expanded to 171 MW. Eventually, this led to the need to upgrade transmission lines delivering power from the plant to users, including the 161 kV Fitzhugh-SPA (Southwestern Power Administration) line.
However, this line had a unique challenge for AECC. ACSR Dove conductor was installed on most of the line, but, to meet clearance requirements set by the Army Corps of Engineers, an ACSR Brahma conductor, which has more steel than aluminum, was used for the section of the line that crosses the Arkansas River. When it was time to upgrade the line's capacity, AECC had trouble finding a conductor that could maintain the clearances over the river and carry the additional power that was needed. As a result, by 2012, that section was acting as a fuse on the line.
To solve the issue, AECC decided to use 3M™ ACCR 557-T23 (283 mm²) on the river crossing. Using 3M's advanced conductor allowed AECC to continue to meet the clearance requirements using the existing structures. In addition, they got a large enough capacity increase to meet current demand and forecasted increases, while keeping project costs to a minimum.
AECC is the latest in a group of public power entities to solve transmission and distribution upgrade challenges with 3M ACCR. These entities include other rural electric co-ops (REC) such as Guadalupe Valley Electric. GVEC replaced conductor on the 138 kV Schertz to Parkway line to increase ampacity by 60 percent cost effectively. Also, municipals, such as the City of Palo Alto, Platte River Power Authority and Silicon Valley Power, and federal agencies and public utility districts, such as Western Area Power Authority and Grays Harbor PUD, continue to use ACCR.
In 2009, ACCR became eligible for use in projects financed by the Rural Utilities Service (RUS) Electric Programs when it was included on the IP202-1 List of Materials Acceptable for Use on Systems of USDA Rural Development Electrification Borrowers.
The light-weight, low-sag conductor enables the use of fewer or shorter towers across environmentally sensitive areas. In addition, 3M ACCR's low-sag properties can improve or maintain clearances across pastures and grazing lands, as well as above distribution or telecommunication wires running on the same poles. In municipal areas, using existing structures for capacity upgrades minimizes disruption to the community.
To get more information on how 3M ACCR might help you or to find your account manager, browse this site or contact us.
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3M High Capacity Conductor Group Updates Data
3M recently updated some of the product
property data for 3M™ ACCR.
The keys to the conductor's proven performance have not changed. The conductor's core is still composed of thousands of alumina fibers embedded in high purity aluminum. This core significantly reduces both weight and sag caused by high energy and mechanical loads. Therefore, the conductor can still give you up to twice the capacity of standard aluminum and steel conductors on existing transmission. Also, the conductor's reliable all metal-based materials and multi-strand design have not changed. And it still has a track record of successful installations that spans more than a decade.
However, 3M has incorporated additional learnings in its product property values:
- The resistance values for AC currents have been adjusted using a calculation method that reflects the effect of diameter and DC resistance. Previously a constant value for the AC/DC conversion was used. For most conductors the effect is relatively small. The most affected values are for large conductors at low temperatures.
- For both round wire and trapezoidal wire conductors, the heat capacities of the core materials have been modified to include the heat capacity of the fiber as well as the matrix material.
- For the trap wire conductors, the strandings and diameters more accurately reflect our experience with how these conductors are manufactured.
To be sure you are working with the up-to-date values, download:
You can also get updated SAG10® files through Southwire.
Or you can contact us online or at 1-800-245-3573
3M Updates the ACCR Installation Guide
The 3M HCC Group has updated its installation guide to include:
- A new section on setting up the reel stands with the tensioner, including helpful diagrams.
- A change in the type of conductor grip recommended for use with 3M™ ACCR from a DG, or distribution grip, to a TG, or tensioning grip.
- A table of required torque by bolt size in the section on installing connectors.
- An updated table of conductor properties and required quantities of high temperature filler compound.
We added links to two new videos to the interactive version of the guide – one on installing suspensions and one on installing connectors and jumpers.
You can also see the videos on the ACCR YouTube channel: http://go.3M.com/ACCR_YouTube.
Other features of the interactive guide include a live table of contents, allowing you to find a section by clicking on it. Or, you may enter the topic in the search box to see all of the places where that subject appears in the
guide. Rich with tables, photos and video, the guide offers single- and double-page views, multiple zoom levels, and the ability to insert electronic Post-It® Notes with comments any place in the document. It also provides contact information, including a link to send an e-mail directly to one of our installation experts.
You can download or print the updated guides in .pdf or interactive versions here. If you have the Apple® or Android™ app, you will automatically receive a notice when the update is available.
Downloading the interactive desktop version or the app allows you to use the interactive features, even if working in an area where internet access is not available.
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Join Us At an Upcoming Event
3M's high capacity conductor group will be participating at:
CIGRE 2014 Technical Exhibition, Booth 216
August 25 – 29, 2014
Palais des Congres, Paris, France
47th Annual TSDOS
September 10 – 12, 2014
University of Texas -- Arlington
CEATI International Transmission Conference
October 2 -3, 2014
Niagra Falls, Ontario
EEI Fall TD&M Conference
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October 5 – 8, 2014
St. Louis, Missouri