Assessing the Impact of Galvanic Corrosion on the Ampacity of ACSR/TW and ACCC/TW Conductors

Galvanic corrosion may happen to overhead conductors with dissimilar metal composition and would adversely affect the conductors’ structural durability, electrical performance, and lifetime. The deterioration resulting from corrosion may accelerate the degradation of the conductors if left unaddressed. This paper aims to assess the impact of galvanic corrosion on the ampacity of commonly used Aluminium Conductor Steel Reinforced (ACSR/TW) and the more advanced Aluminium Conductor Composite Core (ACCC/TW). By using the COMSOL Multi-Physics software, the electrochemical reactions that happened during corrosion between materials within the conductors are modeled. Consequently, the conductors’ electrical conductivity and its ampacity are estimated based on the structural deformation level experienced by the aluminium strands. The results indicate that, bimetallic ACSR/TWs are more susceptible to galvanic corrosion compared to ACCC/TWs resulting in a substantial loss of surface area. A considerable reduction in ampacity up to 12.6%, is noted in the modeled ACSR/TW conductors following 25 months of continuous exposure to corrosion. In contrast, the carbon fiber core of ACCC/TW demonstrates better resistance to galvanic coupling during the same exposure period, thereby contributing to lesser ampacity reduction rate of 10.7%. This research provides an initial study on the galvanic corrosion and its impact on overhead conductor’s ampacity.