Electric field analysis of spacer cable systems under polluted conditions

The use of covered conductors in spacer cable systems (SCS) for compact distribution lines has considerably reduced the failure rates on distribution feeders installed in some inland areas of Mexico. However, in coastal areas, where salt is deposited on the surface of insulators and cable spacers, the use of these systems has important issues. Tracking and erosion of spacers and insulators increases the number of distribution lines outages, forcing the utility company to uninstall these systems. In this paper, finite-element analysis is used to compute the electric-field distribution on an insulated cable system. It is shown how under polluted conditions, the electric stress around the contact area between the covered conductor and the spacer is considerably intensified. In addition, it is discussed how compatibility tests must be performed to reproduce the localization and magnitude of the maximum electric stress that can be measured on field under polluted conditions.