SURFACE MODIFIED OVERHEAD CONDUCTOR

• US 20140041925A1
• Filed: 04/16/2013
• Published: 02/13/2014
• Est. Priority Date: 08/10/2012
• Status: Active Grant

• Current Assignee: General Cable Technologies Corporation (General Cable Corporation)
• Original Assignee: General Cable Technologies Corporation (General Cable Corporation)
• Inventors: MHETAR, Vijay, TEMPLE, William S., BAKER, Gordon, FREESTONE, James, DAVIS, Cody R., RANGANATHAN, Sathish Kumar, ANDERSEN, Ryan, SIRIPURAPU, Srinivas, DOSS, Dennis L.
• Granted Patent: US 9,859,038 B2
• Time in Patent Office: Days
• US Class Current: 174/40.R
• CPC Class Codes: H01B 13/30 Drying; Impregnating H01B13/32 takes precedence
• CPC Class Codes: H01B 3/008 Other insulating material
• CPC Class Codes: H01B 3/02 mainly consisting of inorganic substances
• CPC Class Codes: H01B 3/10 metallic oxides ceramics H01B3/12
• CPC Class Codes: H01B 3/46 silicones
• CPC Class Codes: H01B 5/002 Auxiliary arrangements
• CPC Class Codes: H01B 7/29 Protection against damage caused by extremes of temperature or by flame heat dissipation or conduction H01B7/42
• CPC Class Codes: H01B 7/421 for heat dissipation
• CPC Class Codes: H01B 9/006 Constructional features relating to the conductors
• CPC Class Codes: H01B 9/008 for overhead application

Abstract

The present invention relates to a surface modified overhead conductor with a coating that allows the conductor to operate at lower temperatures. The coating is an inorganic, non-white coating having durable heat and wet aging characteristics. The coating preferably contains a heat radiating agent with desirable properties, and an appropriate binder/suspension agent. In a preferred embodiment, the coating has L* value of less than 80, a heat emissivity of greater than or equal to 0.5, and/or a solar absorptivity coefficient of greater than 0.3.

Claims

1. A surface modified overhead conductor comprising a bare conductor coated with a non-white inorganic coating, wherein when tested in accordance to ANSI C119.4-2004, the operating temperature of the surface modified overhead conductor is reduced compared to the temperature of an unmodified (not containing the heat radiating agent) overhead conductor under a same current.

2. The surface modified overhead conductor of claim 1, wherein the operating temperature is reduced by at least 5°

C. when compared to the operating temperature of the unmodified overhead conductor.

3. The surface modified overhead conductor of claim 1, wherein the L* value of the coating is less 80.

4. The surface modified overhead conductor of claim 1, wherein the coating has an emissivity coefficient of at least about 0.75.

5. The surface modified overhead conductor of claim 1, wherein the coating has an emissivity coefficient of greater than 0.5 and a solar absorptivity coefficient of greater than 0.3.

6. The surface modified overhead conductor of claim 1, wherein the coating comprises organic material of less than 5% by weight of the total dry coating.

7. The surface modified overhead conductor of claim 1, wherein the coating thickness is less than about 200 microns.

8. The surface modified overhead conductor of claim 1, wherein the conductor passes mandrel bend test after heat aging at 325°

C. for 1 day and 7 days.

9. The surface modified overhead conductor of claim 1, wherein the coating has a coefficient of thermal expansion in the range of about 10×

10<sup>−

6</sup> to about 100×

10<sup>−

6</sup>/°

C. over temperatures of 0°

C. to 250°

C.

10. The surface modified overhead conductor of claim 1, wherein the conductor comprises one or more conductive wires of copper, or a copper alloy, or an aluminum or aluminum alloy, including aluminum types 1350 alloy aluminum, 6000-series alloy aluminum, or aluminum-zirconium alloy or any other conductive metal.

11. The surface modified overhead conductor of claim 9, wherein the wires are trapezoidal shaped.

12. The surface modified overhead conductor of claim 1, wherein the conductor comprises a core of one or more wires of steel, invar steel, or carbon fiber composite;

and one or more conductive wires around the core, the one or more conductive wires being made of copper, or a copper alloy, or an aluminum or aluminum alloy, including aluminum types 1350, 6000 series alloy aluminum, or aluminum-zirconium alloy, or any other conductive metal.

13. The surface modified overhead conductor of claim 1, wherein the conductor comprises a reinforced composite core.

14. The surface modified overhead conductor of claim 1, wherein the conductor comprises a carbon fiber reinforced composite core.

15. The surface modified overhead conductor of claim 1, wherein the heat radiating agent is contained in a surface coating.

16. The surface modified overhead conductor of claim 1, wherein the outer layer of the conductor wires are coated.

17. The surface modified overhead conductor of claim 1, wherein the conductor is made up of coated wires.

18. The surface modified overhead conductor of claim 1, wherein the outer surface of the conductor is coated.

19. The surface modified overhead conductor of claim 1, wherein a portion of the conductor is coated.

20. The surface modified overhead conductor of claim 1, where in the coating comprises less than about 5% (by weight of the total dry coating) of organic material.

21. The surface modified overhead conductor of claim 1, wherein the coating comprises about 1-20% (by weight of the total coating) of a heat radiating agent, about 60-90% of a binder, and about 10-35% of aluminum nitride, and less than about 5% amino functional siloxane.

22. The surface modified overhead conductor of claim 21, wherein the binder is sodium silicate.

23. The surface modified overhead conductor of claim 21, wherein the amino functional siloxane is dimethylpolysiloxane.

24. The surface modified overhead conductor of claim 21, wherein the dimethylpolysiloxane has a viscosity of about 10-50 centistokes at 25°

C. and/or an amine equivalent of 0.48 milliequivalents of base/gram.

25. The surface modified overhead conductor of claim 21, wherein the aluminum nitride has a specific surface area of less than 2 m²/g and/or the following particle size distribution:

D 10%—

0.4-1.4 microns, D 50%—

7-11 microns, and D 90% 17-32 microns.

26. A method for making a surface modified overhead conductor comprising the steps of

a. preparing a bare conductor;

b. applying a liquid coating mixture on the surface of a conductor to form a coated conductor; and

c. drying the coated conductor.

27. The method of claim 26, wherein step a comprises the steps of sand blasting the conductor, and passing the sand blasted conductor through an air wipe.

28. The method of claim 26, wherein after the air wipe, the number of particles, that are greater than 10 microns in size, on the surface of the conductor are lower than 1,000 per square feet of the conductor surface.

29. The method of claim 27, wherein step a further comprising the step of heating the conductor after the air wipe.

30. The method of claim 29, wherein the heating is by direct flame exposure.

31. The method of claim 26, wherein step b comprises passing the conductor through a flooded die and then through an air wipe.

32. The method of claim 31, wherein the flooded die comprises an annular shaped portion with a center opening through which the bare conductor passes.

33. The method of claim 32, wherein the flooded die further comprises a tube for carrying the liquid coating mixture to the die.

34. The method of claim 32, wherein the flooded die comprises opening ports through which the liquid coating mixture is deposited on to the conductor.

35. The method of claim 26, wherein step c comprises heating the conductor.

36. The method of claim 35, wherein the heating is by direct flame exposure.

37. The method of claim 26, having a line speed of about 10 to about 400 ft/min.

38. A method for making a surface modified overhead conductor comprising the step of coating a conductor with a non-white inorganic coating, wherein when tested in accordance to ANSI C119.4-2004, the operating temperature of the surface modified overhead conductor is reduced compared to the temperature of an unmodified (not containing the heat radiating agent) overhead conductor under a same current.

39. The method of claim 38, wherein the L* value of the coating is less 80.

40. The method of claim 38, wherein the coating has an emissivity coefficient of at least about 0.75.

41. The method of claim 38, wherein the coating has an emissivity coefficient of greater than 0.5 and a solar absorptivity coefficient of greater than 0.3.

42. The method of claim 38, wherein the coating comprises organic material of less than 5% by weight of the total dry coating.

43. The method of claim 38, wherein the coating thickness is less than about 200 microns.

44. The method of claim 38, wherein the conductor passes mandrel bend test after heat aging at 325°

C. for 1 day and 7 days.

45. The method of claim 38, wherein the coating has a coefficient of thermal expansion in the range of about 10×

10<sup>−

6</sup> to about 100×

10<sup>−

6</sup>/°

C. over temperatures of 0°

C. to 250°

C.