When large amounts of energy is transported over longer distances, this is done in the form of high voltage direct current (HVDC). One problem with these cables, however, has been the loss of energy that occurs when the distances increase.
Graduate Students Love Pallen, Amir Pourrahimi and Dongming Liu at the Royal Institute of Technology (KTH) in Stockholm, together with some other scientists working on the problem, have has just announced a scientific paper within the framework of their doctoral work.
“The cable cover is made ten times more insulating than before, which is a great breakthrough. Polyethylene plastic is one of the best insulating materials available. Now it has been made even more isolating. Thanks to this achievement it is possible to increase the voltage in the cables and reduces energy loss. The result is an international breakthrough,” says Richard Olsson, senior lecturer in the Department of Fiber and Polymer Technology at KTH.
To achieve the best possible insulation, it is important that the polyethylene resin constituting the cable jacket is as clean as possible from contamination. This is necessary to be able to increase the voltage without burning the cable. It's hard to get it really clean, and there are always some impurities left from the manufacturing process. The scientists have instead added "pollution" in the form of highly pure nanoparticles.
“It's about adding the right amount and at the same time distributing the nanoparticles as evenly as possible in the plastic. By doing this, there are no points where electric charging concentrations can be built up, which can cause the cable to burn off when the voltage is increased,” says Richard Olsson.
Love Pallet, Amir Pourrahimis and Dongming Liu's work is of such importance that it has recently been published on the front page of the Journal of Materials Chemistry A. The result is patented by the partner Borealis AB. The work was funded by the Foundation for Strategic Research (SSF).