Graveyard shifts for grid reliability

The city of Prosser, Washington, will go dark for ten hours on the weekend of April 21, as Grand Coulee, Ellensburg and Pasco Transmission Line Maintenance and Ashe Operations crews perform maintenance for reliability of the regional power grid. This will be the second of two planned midnight outages, allowing crews to work safely, while minimizing the length of time without electricity for approximately 6,000 residents.

Located 35 miles west of the Tri-Cities, Prosser is home to farms, orchards and wineries, dubbing itself the “birthplace of Washington wine.” In recent years, the local irrigation district has experienced an increased demand for power to meet the needs of its growing agricultural industry. 

A single transmission line feeds Prosser, putting it at increased risk for outages as regional loads grow. BPA’s current switch configuration, the collection of devices used to connect and disconnect portions of the electrical system, does not allow maintenance without significant disruption of power to the city. 

Typically, line maintenance take place about every six years. Due to the difficulty of scheduling outages, three separate BPA projects are happening simultaneously to minimize impacts to the city.

“Intricate coordination among the three projects is required to do the work and stay out of each other’s way while minimizing the inconvenience to Prosser,” said TEPL project engineer Andrew Young.

To facilitate the work, a temporary shoofly crossing was constructed. It creates a temporary bypass around the whole system, enabling BPA to keep Prosser energized while several sectionalized outages take place to facilitate the different projects.

BPA will soon interconnect Benton Rural Electric Association’s new Huard Road Substation, built primarily to serve the increased demand for power from the local irrigation district. Another project replaces and reconfigures switches at the BPA Prosser Tap to the Grandview-Red Mountain No. 1 transmission line so that a single disconnect will not result in area outages. And the third project has crews correcting impairments along 22 miles of the Grandview-Red Mountain No. 1 line, enhancing safety and reliability, and preventing potential damage to equipment from wildfires.

Work will continue in the fall and is expected to be completed by May 2024, as realty acquisitions, priority pole replacements and the remainder of the switch construction are completed.