Composite Insulators in a 400 kV AC Line in Algeria for Improving Electric Field Distribution

Composite insulators are widely used in the 60 and 220 kV transmission lines in Algeria. The reliability of these lines has been improved which leads us to think of integrating this type of insulators in the 400 kV transmission lines recently introduced by the Algerian Company of Electric Power and Gas (SONELGAZ) where glass insulators are used. Thus, in this paper, we evaluated at first the electrical performances in terms of electric field distribution on three proposed composite insulators with different shed configurations under different surface conditions (dry and clean, uniformly polluted and in presence of water droplets). Then, we compared the electric field distribution of the selected composite insulator to the already used made of glass in the 400 kV AC line of TILGHEMT-DJELFA in Algeria under normal and contaminated surface conditions. Using 2D simulation, composite insulators presented better electric field distribution. Finally, the generated heat along insulator surface is estimated for both composite and glass insulators under different surface conditions. Note that an appropriate corona ring is used at both HV and ground ends for glass and composite insulators with constant parameters (corona ring diameter, corona ring tube diameter and corona ring height) throughout the whole study.