The aerial bundled cables (ABC) and the characteristics of its semiconductive shield

The aerial bundled cables (ABC) for overhead distribution systems (15 kV and 25 kV) has been a good solution for Brazilian electrical utilities when applied either in areas with limited space on poles and to satisfy claimed performance in tree areas or narrow streets, focusing personal safety and electrical service continuity. Otherwise its external semiconductive layer, that has the functions of controlling the electrical field, draining the insulation current to ground through the messenger conductor, and to resist against external abrasion, has shown an unexpected performance as seen by failures like punctures, electrical tracking and erosion. This work presents the results of an investigation of the semiconductive material and its thermal and electric behavior, measured by its electrical resistivity, dielectric constant and melting heat. The obtained results led to a set of requirements to specify the semiconductive layer and a proposal to change the national standard for the ABC cables.