/images/TDUpdate2.gif/images/southwire_100x70.jpgUltra-High Strength Steel Upgrades Danis Grid - 2008UltraHiStrengthSteelUpgradesDanisGridFeb2008.htmThe ancient Vikings didn’t worry about power grid capacity. Modern Danes do. As in the U.S. their problem is how to increase grid capacity cost-effectively.
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Ultra-High Strength Steel Upgrades Danis Grid - 2008

High-temperature, low-sag conductors lead ACSS/TW expansion into Europe.

The ancient Vikings didn’t worry about power grid capacity. Modern Danes do. As in the U.S. their problem is how to increase grid capacity cost-effectively. Building new towers to carry larger, heavier conductors can push upgrade budgets past the breaking point. A new conductor design from Southwire offers solutions.

Reconductoring made upgrade affordable

On Denmark’s Jutland peninsula, the Danish utility operator N1 is increasing capacity with existing towers. They have reconductored using Southwire’s ACSS/TW (aluminum conductor, steel supported, trapezoidal wire) conductors with a new ultra-high-strength steel core Southwire calls HS285® (See box below for details of the HS285 ACSS/TW architecture.)

The project is a double-circuit 170kV line stretching 22.5 miles (36 km) between the cities of Trige and Tange. The line was built in 1963, using ACSR (aluminum conductor, steel reinforced) conductors with a capacity of 980 A. N1 wanted 1,500 A down the same right-of-way. The problem was finding a cost-effective approach.

Several approaches were considered

N1 worked with Otra Danmark A/S, a Southwire agent and supplier of overhead conductors, and equipment to the Danish utility market. N1 and Otra reviewed environmental impact, installation costs and operating economy. In the end, the only alternative that met the needs of price and performance was the newly developed HS285 solution. It required no structural modifications to the existing towers.

“Southwire has 25 years of experience with the ACSS/TW conductor architecture,” says Neilsen. “That was an important factor in making the choice.” Mark Lancaster, Senior Product Engineer, adds, “Southwire designed a steel-core, high-temperature low-sag conductor with specifications tailored to the application.”

N1 and Otra then took a full year testing and confirming the performance of the new design. “Otra helped N1 with technical assistance in sag, tension, and tower-strength calculations,” says Merete Neilsen, manager of power and networks for Otra.

Southwire ACSS/TW experience was a factor

N1’s Trige-to-Tange project was energized in mid-November of 2006. The upgrade used a total of 137.5 miles (220 km) of 954 kcmil Cardinal ACSS/TW conductor with the HS285 steel core

Because the ACSS/TW architecture is relatively new to Europe, a team from Southwire inspected the site, trained installers and consulted with Otra engineers.

“This project is the first of its kind in Denmark and this type of upgrading is only carried out a few places in Europe,” Neilsen says. “We’re pleased with the results.” Lancaster adds, “We’re expecting to see growth in the use of ACSS/TW conductors in Europe as grid operators continue to confront the cost of upgrade projects.”