Hawaiian Electric Co. has nearly 1300 structures on its 28 138-kV transmission circuits that span the island of Oahu. The system is isolated with no interconnections to other utilities. A single structure failure should not cause customer outages, but the system is at an increased risk for overload and outages if additional failures occur. More than 35% of the transmission structures have been in service more than 40 years and nearly 20% have been in service more than 50 years. Because of its aging transmission infrastructure, Hawaiian Electric has begun replacing the existing transmission structures.
Following are images of the construction process including examples of infrastructure that needs attention. For more in-depth reading, see "Construction Challenges in Paradise," which originally appeared in the February 2019 issue of T&D World.