Utility´s strategic application of short underground transmission cable segments enhances power system

Overhead lines are generally the preferred means to transfer power due to their generally lower cost and higher transmission capacity, particularly in rural settings, as compared to power cables. However, underground transmission segments can be important links in transmission circuits where lines are impractical. One utility uses strategic applications of cable segments to build transmission lines and enhance the power system through in-station ties. This comes with various challenges including matching overhead line or station bus capacity, reliability considerations, supporting a viable inventory of spare parts, and coordinating construction activities around available outages. This paper summarizes the design choices and project challenges considered during implementation of six cable projects on the Delmarva peninsula in 2012 and 2013 that significantly expanded the reliability of the utility´s power system.