Thermal Characteristics of Trapezoidal Overhead Conductors Exposed to Galvanic Corrosion

Abstract

The ampacity of overhead conductors is primarily determined by their thermal characteristics. However, current ampacity techniques assume that conductors are in an uncorroded state, a simplification that fails to account for the effects of corrosion. This oversight can lead to elevated operating temperatures in corroded conductors, potentially violating ground clearance requirements, reducing service life, and increasing public safety risks. This study utilizes COMSOL Multiphysics software to model the development of galvanic corrosion on Aluminum Conductor Steel Reinforced (ACSR) conductors with trapezoidal wires, which are commonly used in corrosive environments. Subsequently, the study applies heat transfer modelling to examine the thermal characteristics of these corroded conductors. The findings reveal that galvanic corrosion leads to a loss of conductive area in the aluminum strands, which reduces the overall conductive capacity. Under predefined ampacity conditions, this reduction causes increased temperatures at the core-aluminum interface for ACSR/TW conductors, leading to higher overall conductor temperatures. The reductions in the conductive area for Santee/TW, Martin/TW, and Hawk/TW ACSR are 4%, 8%, and 11%, respectively, resulting in temperature increases of 3°C, 4.4°C, and 5.5°C. These results highlight for the importance of considering corrosion on the ampacity determination.