Melhoramento de desempenho face às descargas atmosféricas, de linha de transmissão de energia eléctrica de 110kv e 49 km que interliga as subestações de Macia e Chicumbane (CL2)

Abstract

The 110 kV CL2 transmission line (Macia–Chicumbane) presents significant vulnerabilities, with a high number of outages mainly caused by lightning strikes. These issues are primarily due to the absence of an overhead ground wire since the line’s implementation—a solution deemed unfeasible due to safety constraints (isolation distances) and structural weaknesses of the towers. To mitigate these outages, standardised methods have been proposed, including the installation of line surge arresters to divert surge currents safely to ground, thereby protecting insulators and preventing unnecessary trips; improvement of tower grounding resistance through grid restructuring and successive measurements to ensure effective current dissipation; and the installation of larger insulator sheds to increase the creepage distance and enhance insulation performance under overvoltage conditions. These methods will be evaluated through technical calculations and feasibility studies to assess their effectiveness in significantly improving the reliability of the transmission line against lightning-induced outages.