Southwire has developed a new high-quality, high-strength and cost-effective overhead conductor with significant performance advantages over existing designs for overhead lines designed to handle extreme ice loads.
“We define extreme ice as buildup that is greater than 1 inch thick around the conductor,” said Paul Springer, Southwire’s director of overhead transmission engineering. “While those conditions typically occur in the far north, transmission lines as far south as Texas are being designed for extreme ice to guard against the expected increase in super storms and a more variable climate.”
“Our Max Ice overhead conductors sag less under heavy ice loads. That saves the transmission owner money, because support structures don’t need to be as tall,” Springer explained. “Max Ice is also extremely rugged and will save utilities on downtime and repair costs following major storm events.”
The high mechanical strength of Max Ice overhead conductors can increase the strength margins for the longest spans and most extreme storm conditions. Benefits include:
- Smaller conductor size: The high-temperature aluminum alloy used in the wire means Max Ice conductors are half the size of the same-capacity conventional ACSR conductor. Smaller conductor size means less ice weight for the same ice thickness around the conductor. Lower weight reduces sag and puts less stress on transmission towers.
- Reduced tower height and cost: Tower costs increase rapidly with increasing tower height. In extreme ice areas, sag during expected icing conditions requires significantly taller structures to maintain safe electrical clearances. With a 2-inch thick ice load in a 1,200-foot span, the Max Ice overhead conductor has 5 feet less sag than any commercially available alternative.
- Increased strength margins: Because of its extremely high breaking strength, Max Ice handles extreme ice loads with a higher safety margin than other commercially available alternatives.
The Max Ice conductor is composed of:
The conducting component. High temperature-tolerant ZTAL (AT-3) Aluminum Zirconium alloy contributes to the high conductor strength, while at the same time allows for thermal ratings of 210 degrees C for continuous operations and 240 degrees C for limited emergency operations.
The core. Ultra-high-strength steel allows for higher stringing tensions and higher safety margins.
The coating. Mischmetal alloy has a high heat tolerance and excellent corrosion protection.
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