Mammoet completes setting of three transformers for Seattle City Light

Setting a transformer
Setting a transformer

Seattle, Washington - To deal with the power needs of one of the fastest growing cities in the US, Seattle City Light is constructing one of its largest electrical substations, the Denny Substation, near the I5 and Denny Way. The construction represents a major upgrade to the existing infrastructure. A two year design process with stakeholders helped with the design, and consistent public updates informed the public of progress and disruptions in the area.
Mammoet was part of a network of contractors working closely together. Mammoet successfully hoisted three 125 ton transformers. The use of a crane with sufficient reach, a LTM1400, performed the lifting operations and the setting of foundations from a single location. This was necessary as the compact construction area limited crane movements. As a response to this, Mammoet was able to eliminate crane movements altogether, saving time in the execution.

The installation of four 15kV metal clad capacitor banks was also the responsibility of Mammoet. Overhead obstructions prevented the banks from being directly lifted into place. To work around this obstacle the banks were hoisted onto a jack and slide rail system, from which they were set on their foundations.

Robert George Sr., Construction Manager for ABB, stated “The success of this evolution is a result of endless coordination, months of planning and first class teamwork! I am impressed and appreciative of the way everyone pulled together as a team to ensure a safe and successful event”.

The project is ongoing and the substation is set to be energized in early 2018.