An assessment of graphitized carbon fiber use for electrical power transmission

Abstract

Significant progress has been made in the last few years toward the production of a highly conductive carbon filament. Graphitized carbon fibers, made from a variety of precursor materials such as rayon, polyacrylonitrile (PAN), pitch, mesophase pitch and benzene, have electrical conductivities in the range 10 6 − 10 7 (Ω m) −1 , tensile strengths in the range 1–3 GPa, tensile moduli in the range 100–700 GPa and densities in the range 1.8 −2 2.2 × 10 3 kg/m 3. These properties suggest that graphitized fibers may have potential as current carriers for electrical power transmission. This paper examines the physical reasons for the electrical and mechanical properties and evaluates prospects for fibers with better electrical conductivity without degradation of mechanical properties. Chemical doping (intercalation) of the highly graphitized carbon fibers is found to be capable of achieving increases in conductivity of 5 to 15 times with some degradation in tensile strength. Various applications for electrical power transmission usage are examined, i.e., underground and overhead conductors, underground pipe, overhead towers and submarine cable. Near-term usage is most probable in towers and submarine cable, where high strength-to-weight advantages may offset the present failure of fiber electrical conductivity to equal aluminum or copper values.