Electrical Transmission Cables With Composite Cores

Abstract

The present invention discloses electrical cables containing a cable core and a plurality of conductive elements surrounding the cable core. The cable core contains at least one composite core, and each composite core contains a rod which contains a plurality of unidirectionally aligned fiber rovings embedded within a thermoplastic polymer matrix, and surrounded by a capping layer.

1 - 20 . (canceled) 
     
     
         21 . 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 carbon fibers 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 polyphenylene sulfide, and wherein the rod comprises from about 30 wt. % to about 75 wt. % carbon fibers; and 
 (ii) a capping layer surrounding the at least one rod, wherein the capping layer contains less than 5 wt. % of carbon fibers; and 
   (b) a plurality of conductive elements surrounding the cable core.   
     
     
         22 . The cable of  claim 21 , 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 m to about 9.5 m; and/or   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 m to about 7.5 m.   
     
     
         23 . The cable of  claim 21 , wherein the cable has:
 a 10-year creep value at 15% RBS (rated breaking stress) of less than about 0.2%; and/or   a 10-year creep value at 30% RBS (rated breaking stress) of less than about 0.25%.   
     
     
         24 . The cable of  claim 21 , wherein the capping layer:
 has a thickness in a range from about 0.01 mm to about 10 mm;   contains less than about 1 wt. % of carbon fibers; and   comprises a polyether ether ketone.   
     
     
         25 . The cable of  claim 21 , wherein the cable passes an Aeolian vibration test at 100 million cycles. 
     
     
         26 . The cable of  claim 21 , further comprising a partial or complete layer of a tape or a coating between the cable core and the plurality of conductive elements. 
     
     
         27 . The cable of  claim 21 , wherein:
 the cable core comprises from 2 to 37 composite cores; and   the cable comprises up to 84 conductive elements arranged in 2, 3, or 4 layers around the cable core.   
     
     
         28 . The cable of  claim 27 , wherein:
 the conductive elements comprise copper, a copper alloy, aluminum, an aluminum alloy, or any combination thereof; and   the conductive elements have a substantially circular cross-sectional shape or a substantially trapezoidal cross-sectional shape.   
     
     
         29 . The cable of  claim 27 , wherein the conductive elements comprise aluminum or an aluminum alloy having an IACS electrical conductivity in a range from about 59% to about 65%. 
     
     
         30 . The cable of  claim 27 , wherein the cable comprises 7, 19, 26, or 37 conductive elements. 
     
     
         31 . The cable of  claim 21 , wherein the cable is a high voltage overhead transmission cable. 
     
     
         32 . The cable of  claim 21 , wherein the composite core has:
 a flexural modulus of from about 15 to about 200 GPa;   an ultimate tensile strength of from about 500 MPa to about 3,500 MPa; and   an elastic modulus in a range from about 70 GPa to about 300 GPa.   
     
     
         33 . The cable of  claim 21 , wherein the composite core has:
 a percent elongation at break in a range from about 1% to about 2.5%; and/or   a linear thermal expansion coefficient in the longitudinal direction in a range from about −0.4 to about 5 ppm per ° C.   
     
     
         34 . The cable of  claim 21 , wherein the composite core has a bending radius in a range from about 1 cm to about 50 cm. 
     
     
         35 . The cable of  claim 21 , wherein:
 the rod comprises from 2 to 20 rovings; and   each roving comprises from about 1,000 to about 100,000 individual fibers.   
     
     
         36 . The cable of  claim 21 , wherein the composite core has a void fraction of about 4% or less. 
     
     
         37 . The cable of  claim 21 , wherein the capping layer has a thickness in a range from about 0.01 mm to about 10 mm and contains less than about 1 wt. % of carbon fibers. 
     
     
         38 . The cable of  claim 21 , wherein the capping layer contains 0 wt. % of carbon fibers. 
     
     
         39 . The cable of  claim 38 , wherein the capping layer comprises a polyether ether ketone. 
     
     
         40 . The cable of  claim 38 , wherein the capping layer has a thickness in a range from about 0.02 mm to about 5 mm.