An outdoor laboratory at the U.S. Oak Ridge National Laboratory (ORNL) is proving crucial for conducting accelerated lifetime testing of overhead conductors and line monitoring equipment using a DC power supply. The Powerline Conductor Accelerated Testing Facility (PCAT) enables utilities and manufacturers to evaluate new transmission line technologies for long time periods in extremes of wind, weather, temperature and electrical load conditions.

Testing goals encompass increasing operating lifetime and the amount of current a line can handle and lowering operating temperature through materials choices. The isolated power transmission lines comprising PCAT, which includes 2,400 ft of overhead test conductor spanning three towers and monitored by a suite of sensors, recently hosted an extended demonstration of a robot-applied coating developed by Prysmian. The coating is engineered to reduce the amount of heat retained in the cable and increasing its power transmission capacity.

After six months of power cycling tests, the robotically coated line remained as much as 57° C cooler as an uncoated power line, allowing the same conductor to carry more current while also operating more efficiently.

“Being able to cycle current to achieve specific temperature extremes helps us see how the conductor resistance may change with the expansion and contraction of conductors, connectors and other components over time when they are hanging under tension from a tower at high elevation,” explained ORNL researchers.

Such testing accelerates the deployment of new conductor technologies such as various aluminum core shapes, novel aluminum alloys and carbon fiber to replace aluminum or steel cores. These innovations can also help reduce the amount of electricity lost during transmission.