Evaluation of Mixed Systems for Sheath Bonding of Single-Circuit Underground Power Lines

This paper investigates and presents the application of mixed systems for sheath bonding in single-circuit underground transmission lines, considering both triangular and flat formations. The employed mixed systems included methods such as sectionalized cross-bonding (SCB) along with single-point bonding (SPB), as well as continuous cross-bonding (CCB) combined with single-point bonding (SPB). Additionally, the extension of SCB for two minor section, known as midpoint (MP), also was considered, offering alternative approaches to sheath bonding beyond SCB and CCB. These mixed systems are utilized when the induced voltage on the sheath exceeds the maximum limit set by employing solely SCB or CCB methods. The analysis demonstrates that rather than increasing three smaller sections for a new SCB or CCB connection, the mixed system requires only one for single-point bonding or two for mid-point bonding. This results in fewer joint boxes, reduced costs, and shorter durations for civil and electromechanical works.