One such conductor is described in patent document JP 03-129606.
In that prior art document, the composite core is constituted by organic or inorganic fibers, e.g. of aramid, silicon carbide, or carbon, impregnated by a synthetic resin, preferably an epoxy resin. The core may be covered in a polyamide resin or taped in a polyimide film, so as to form an insulating layer. Aluminum conductor wires are wound around such a core or a set of such cores so as to form a power transmission conductor.
The polyimide covering serves in particular to prevent problems of corrosion at the interface between the conductor wires and the core including carbon fibers.
Given the non-zero resistivity of carbon fibers, some of the main current is diverted from the layers of aluminum or aluminum alloy conductor wires through the capacitor formed by the combination of said conductor wires, the insulating layer, and the carbon fibers. A potential difference thus appears across the terminals of the insulating layer. This potential difference gives rise to an electric field that is potentially unacceptable for the insulating layer, regardless of the nature of the thermosetting material of the matrix, regardless of the nature and the implementation of the insulating layer, and regardless of the number of layers of conductor wires.
By calculation, it can be shown that the voltage induced across said insulating layer is a function of the length of the conductor, and of the transmitted current, and is independent of the voltage between phases.
These conductors are for transmitting power at currents that may be equal to twice the corresponding current of an equivalent conventional cable, so the voltage induced across the insulating covering can cause damage thereto in the short or medium term.
To solve this problem, the invention provides a power transmission conductor, in particular for overhead electric lines, and including at least one central composite core made up of continuous fibers impregnated by a thermosetting resin matrix, the core being coated by at least one layer of insulating material, with aluminum or aluminum alloy conductor wires being wound around the core, the conductor including a short-circuiting device for short-circuiting said fibers with said conductor wires.