There is a system for de-icing power transmission cables that divides the cable into several sections. Switches are placed at the end of each section so that the conductors are connected in parallel in a normal manner, and at least some of the conductors in the series are anti-freeze mode. When switches are bundled to control a series of conductors, the electrical resistance of the cable section will effectively increase so that the cable is automatically heated by the power line current and thus unfreezes the cable; the switches and conductors are connected in parallel to reduce energy loss. In convertible form, the system can deliver electrical current through the steel's strength core to de-ice the cable, while in normal operation the current passes through the lower-resistance conductor layer. Backup hardware is used to restore the system to a low-resistance operating mode where the cables can overheat.
Related applications:
The current application is owned by U.S. Provisional Patent Application Serial Number 61/041,875, authorized on April 2, 2008, and all relevant interpretation rights belong to the company all.
Field
The current document belongs to overhead transmission lines (professional term, not sure). In particular, it is relevant to systems for de-icing power transmission cables or to ways to prevent losses due to the weight of accumulated ice.