Electrical transmission cables with composite cores

1. An electrical cable comprising:

(a) a cable core comprising at least one composite core, the composite core comprising:

(i) at least one rod comprising a plurality of consolidated thermoplastic impregnated rovings, the rovings comprising continuous fibers oriented in the longitudinal direction and a thermoplastic matrix that embeds the fibers, the fibers having a ratio of ultimate tensile strength to mass per unit length of greater than about 1,000 MPa/g/m, wherein the rod comprises from about 25 wt. % to about 80 wt. % fibers and from about 20 wt. % to about 75 wt. % thermoplastic matrix; and

(ii) a capping layer surrounding the at least one rod, wherein the capping layer is free of continuous fibers;

wherein the composite core has a flexural modulus of at least about 10 GPa; and

(b) a plurality of conductive elements surrounding the cable core.

2. The cable of claim 1 , wherein:

the fibers comprise carbon fibers; and

the thermoplastic matrix comprises a polyphenylene sulfide.

3. The cable of claim 1 , wherein:

the fibers have a ratio of ultimate tensile strength to mass per unit length of from about 5,500 to about 20,000 MPa/g/m; and

the capping layer comprises a thermoplastic polymer having a dielectric strength of at least about 2 kV/mm.

4. The cable of claim 1 , wherein the composite core has:

a flexural modulus of from about 15 to about 200 GPa; and

an ultimate tensile strength of from about 500 MPa to about 3,500 MPa.

5. The cable of claim 1 , wherein the composite core has:

an elastic modulus in a range from about 70 GPa to about 300 GPa; or

a density in a range from about 1.2 g/cc to about 1.8 g/cc; or

a strength to weight ratio in a range from about 500 MPa/(g/cc) to about 1,100 MPa/(g/cc); or

a percent elongation at break in a range from about 1% to about 2.5%; or

a linear thermal expansion coefficient in the longitudinal direction in a range from about −0.4 to about 5 ppm per ° C.; or

a bending radius in a range from about 1 cm to about 50 cm; or

a void fraction of less than about 6%; or

any combination thereof.

6. The cable of claim 1 , wherein:

the rod comprises from 2 to 20 rovings; and

each roving comprises from about 1,000 to about 100,000 individual continuous fibers.

7. The cable of claim 1 , wherein the cable core comprises two or more composite cores.

8. The cable of claim 7 , wherein the cable core is a stranded core comprising from 2 to 37 composite cores, each composite core having a substantially circular cross-sectional shape.

9. The cable of claim 1 , wherein the cable comprises up to 84 conductive elements, and wherein a total area of the conductive elements is in a range from about 167 to about 3500 kcmil.

10. The cable of claim 9 , wherein:

the conductive elements comprise copper, a copper alloy, aluminum, an aluminum alloy, or any combination thereof; or

the conductive elements are arranged in 2, 3, or 4 layers around the cable core; or

the conductive elements have a substantially circular cross-sectional shape or a substantially trapezoidal cross-sectional shape; or

any combination thereof.

11. The cable of claim 10 , wherein the conductive elements comprise aluminum or an aluminum alloy having an IACS electrical conductivity in a range from about 59% to about 65%.

12. The cable of claim 1 , wherein the cable has:

a sag, at rated temperature of 180° C., for a 300-meter level span with a NESC light loading, in a range from about 3 to about 9.5 m; and

a sag, at rated temperature of 180° C., for a 300-meter level span with a NESC heavy loading, in a range from about 3 to about 7.5 m.

13. The cable of claim 1 , wherein the cable has:

a stress parameter in a range from about 20 MPa to about 50 MPa; or

a 10-year creep value at 15% RBS (rated breaking stress) of less than about 0.2%; or

a 10-year creep value at 30% RBS (rated breaking stress) of less than about 0.25%; or

a maximum operating temperature in a range from about 100° C. to about 250° C.; or

any combination thereof.

14. The cable of claim 1 , wherein the cable passes an Aeolian vibration test at 100 million cycles.

15. The cable of claim 1 , further comprising a partial or complete layer of tape between the cable core and the plurality of conductive elements.

16. An electrical cable comprising:

(a) a cable core comprising at least one composite core, the composite core comprising:

(i) at least one rod comprising a plurality of consolidated thermoplastic impregnated rovings, the rovings comprising continuous carbon fibers oriented in the longitudinal direction and a thermoplastic matrix that embeds the carbon fibers, the carbon fibers having a ratio of ultimate tensile strength to mass per unit length of greater than about 1,000 MPa/g/m, wherein the thermoplastic matrix comprises a polyarylene sulfide, and wherein the rod comprises from about 30 wt. % to about 75 wt. % carbon fibers and from about 25 wt. % to about 70 wt. % thermoplastic matrix; and

(ii) a capping layer surrounding the at least one rod, wherein the capping layer comprises a polyether ether ketone and is free of continuous carbon fibers;

wherein the composite core has a flexural modulus of at least about 10 GPa; and

(b) a plurality of conductive elements surrounding the cable core, wherein the conductive elements comprise aluminum or an aluminum alloy.

17. The cable of claim 16 , wherein the cable is a high voltage overhead transmission cable.

18. The cable of claim 16 , wherein:

the cable core comprises 7 composite cores or 19 composite cores; and

the cable comprises up to 50 conductive elements arranged in 2, 3, or 4 layers around the cable core.

19. The cable of claim 16 , wherein the composite core has:

a flexural modulus of from about 15 to about 200 GPa; and

an ultimate tensile strength of from about 500 MPa to about 3,500 MPa.

20. The cable of claim 16 , wherein:

the polyarylene sulfide is a polyphenylene sulfide; and

the conductive elements have a substantially trapezoidal cross-sectional shape.