Coated overhead conductor
A polymeric coating can be applied to an overhead conductor. The overhead conductor includes one or more conductive wires, and the polymeric coating layer surrounds the one or more conductive wires. The overhead conductor can operate at a lower temperature than a bare overhead conductor with no polymeric coating layer when tested in accordance with ANSI C119.4 method. Methods of applying a polymeric coating layer to an overhead conductor are also described herein.
1. A method of increasing the emissivity of an overhead conductor to lower its operating temperature, the method comprising:
surrounding an overhead conductor with a polymer composition, wherein the polymer composition comprises one or more of polyvinylidene difluoride and a cross-linked polyethylene, and wherein the polymer composition is essentially solvent free; and
cooling the polymer composition to form a polymeric coating layer surrounding the overhead conductor; and
wherein the polymeric coating layer contacts at least a portion of the overhead conductor and defines a single outer layer having a thickness of about 10 microns to about 1,000 microns and the overhead conductor operates at a lower temperature than a bare overhead conductor when tested in accordance with ANSI C119.4; and
wherein the method is continuous; and
wherein an externally applied pressure is applied to the overhead conductor during at least one of surrounding the overhead conductor with the polymer composition or cooling the polymer composition, wherein the externally applied pressure is applied from a hot air circular knife.
2. The method of claim 1 , wherein the surrounding the overhead conductor with the polymer composition further comprises heating the polymer composition and extruding the polymer composition around the overhead conductor.
3. The method of claim 1 , wherein the surrounding the overhead conductor with the polymer composition further comprises spraying a powder comprising the polymer composition around an exterior surface of the overhead conductor and then melting the powder.
4. The method of claim 1 , wherein the overhead conductor is pre-heated prior to surrounding the overhead conductor with the polymer composition.
5. The method of claim 1 , wherein the polymeric coating layer is a conformal coating layer and is in contact with an outer contour of the overhead conductor.
6. The method of claim 5 , wherein unfilled spaces between the polymeric coating layer and the outer contour of the overhead conductor are at least partially filled.
7. The method of claim 1 , wherein the polymer composition further comprises one or more of polypropylene, fluoroethylene vinyl ether, silicone, acrylic, polymethyl pentene, poly(ethylene-co-tetrafluoroethylene), polytetrafluoroethylene, and copolymers thereof.
8. The method of claim 1 , wherein the polymer composition further comprises about 50%, or less, filler, and the filler comprises one of carbon black or a conductive carbon nanotube.
9. The method of claim 1 , wherein the polymeric coating layer is semi-conductive and has a volume resistivity of less than 10 10 ohm-cm.
10. The method of claim 1 , wherein the polymeric coating layer has a retention of elongation at break of 50%, or more, after 2,000 hours of exterior weather when tested in accordance with ASTM 1960.
11. The method of claim 1 , wherein the polymeric coating layer has a thickness of about 10 microns to about 500 microns.
12. The method of claim 1 , wherein the polymeric coating layer has an emissivity of 0.80 or greater.
13. The method of claim 1 , wherein the polymeric coating layer has a solar absorptivity of 0.3 or less.
14. The method of claim 1 , wherein the polymeric coating layer has a heat conductivity or 0.15 W/mK or greater.
15. The method of claim 1 , wherein the polymer composition is at least partially cross-linked.
16. The method of claim 1 , wherein the polymer composition is thermoplastic and has a melting temperature of 140° C. or more.