Impact of electromagnetic fields on current ratings and cable systems

The work presented in this paper is a summary of the technical brochure being prepared by CIGRE Working Group B1.23 that focuses on single conductor, high voltage, ac, land cable systems, excluding pipe type and GIL cables. It considers extruded dielectric insulation, laminar dielectric insulation, single-point bonding or balanced cross-bonding, so that there is minimum ground return current. Magnetic field management techniques are discussed that are currently used for underground transmission cable systems and the shielding effectiveness of practical methods is quantified. The cable current de-rating aspects of the various field management methods are presented. This paper does not cover any environmental or biological effects of EMF and does not discuss any specific levels of EMF.