Hooper Corporation expanded the existing 345 kV Harvest Mile Substation located in Aurora, CO to support the addition of a significant amount of renewable generation on the transmission corridor through that area. Hooper crews expanded the 345 kV bus to include 1 new tie position and facilitate the addition of 2 – 345 kV, 120 MVAR capacitor banks that will provide voltage support to the transmission system. In addition, Hooper was tasked with cutting in a new 345 kV circuit breaker and switch to build out the existing ring bus. Hooper’s responsibility’s included the installation of the concrete foundations, ground grid additions, duct bank expansions, steel structures, major electrical equipment, aluminum bus & jumpers, relay panels, low voltage control cable, and the 25kV power cable. Hooper also provided testing & commissioning support for the relay and controls system and was also responsible to help implement and install a new local voltage controller.
Hooper worked directly with utility operations to coordinate and schedule the necessary outages required to cut in the new equipment and energize safely. Outages were needed to cut the existing ring bus, tie the new bus to the ring bus, install the foundations underneath the bus, install and time the new switch, set the new breaker, and install final jumpers. The main challenge with the outages were needing to take the one and only main power transformer offline and work under a strict time constraint to re-energize. In total, Hooper’s crews safely worked over 9,000 man hours taking us to project completion before the required date.