East Epping to Washington County Substation
SGC designed the rebuilt 115kV line section of approximately 12 miles in the Downeast region of Maine. Using a combination of LIDAR, survey, and original plan and profile drawings, a model of the existing line was created in PLS-CADD. In working with Bangor Hydro Electric Company (BHE), SGC developed a plan for structure replacement based on pole conditions. BHE’s plan was to leave as many existing structures in place as possible. SGC created a plan for the line that allowed new structures to be placed outside the wetlands when practicable.
Another facet of the design was the creation of dead-end sections to improve reliability. This project started at a point just beyond a section that had been leveled due to the cascade effect caused by the infamous ice storm of 1998. The damaged section was rebuilt but this final section remained at risk to those same conditions. The design included three new dead-end structures, creating four tension sections.
The line was redesigned using the existing conductor. The new, taller structures allowed for the conductor tension to be reduced slightly, minimizing strain on the old line. SGC’s PLS-CADD model of the existing line proved very accurate in developing the sagging tensions during construction.
SGC supported the construction effort during a difficult winter for line building work. Much of the line was routed through areas that had been designated for frozen conditions during construction due to minimize wetland impacts. SGC assisted BHE in providing timely construction support when conditions forced adjustments. When line construction was complete, nearly 80 structures out of the existing 108 in that section were replaced.