Design innovation improves distribution performance of conductors at high temperatures.
CTC Cable Corporation and Midal Cables have unveiled their energy efficient high temperature, low sag conductors – a first for the industry, the companies claim. The aluminium conductor composite core (ACCC) conductors can carry excess power transmission, without major alterations to existing transmission structures.
Speaking at the Middle East Electricity Exhibition last month, Ahmed Al Awar of CTC said the ACCC conductors should replace aluminium conductor steel reinforced (ACSR) conductors as the most widely used in overhead transmission lines.
“ACSR conductors comprise a steel core surrounded by aluminium wires,” said Al Awar. “But at a certain temperature, when there is a high demand for electricity and power, these conductors reach an output limit. This causes the line to sag. At high temperatures, above 100ºC, aluminium will become softer and elongated.”
To get around this there are two options. The first approach is to increase the constructional area of the aluminium, replacing the steel core with an aluminium one. By doing this the conductor can deliver more current. But the problems of high temperature-induced sagging persists.
“The second approach, which has become the most popular, is that of high temperature application,” added Al Awar.
“This involves reinforcing the conductor with steel and minimising the load on the aluminium. This would allow the conductor to endure higher temperatures, while still being capable of delivering high current.
This way, we can deliver enough current to more than meet demand. These type of conductors can withstand temperatures of up to 250ºC.
“This introduces the idea of energy efficiency. Temperatures this high mean there will be substantial heat loss. This costs money. Steel cores ensure the conductor will stay intact, while the increased constructional area of the surrounding aluminium wires reduce energy loss. However, the conductor is now heavier than before. This re-presents the problem of line sagging. To address this, we replaced the steel core with a carbon composite structure: uni-directional carbon fibres embedded in a polymeric high-temperature matrix. This is 60% lighter than steel, but 25% stronger.”
When pumping 1 600 amps, conventional conductors run at 240ºC or more. But by pumping the same amount of power, ACCC conductors run at 180ºC – at least 60ºC lower.
This is beneficial for the environment and means lower heat losses. With these kind of day-on-day savings, the companies contend the cost of acquiring and installing the conductors would be recouped in less than a year.
In addition, lighter conductors will make new installation systems feasible, involving fewer poles or lower structures.For all the latest energy and oil news from the UAE and Gulf countries, follow us on Twitter and Linkedin, like us on Facebook and subscribe to our YouTube page, which is updated daily.