Transformer Changeout

Journeyman Substation Technician Matt Howell conducts his pre-job safety briefing. Photos by John C. Pynakker/MEC

In the early hours of November 4, crews from Mohave Electric Cooperative (MEC) along with Dielco Crane Service, removed an old transformer in the Willow Valley Substation in Mohave Valley and replaced it with a new transformer to continue to address reliability and load growth for the future.

The old 22 Megavolt Ampere (MVA) transformer was being replaced with a new 37 MVA transformer manufactured by Virginia Transformers in Pocatello, ID.

“The added 15 MVA will allow Mohave Electric to have more options when it comes to emergency switching scenarios during peak loads,” said Matt Howell, Journeyman Substation Technician for MEC. “This will also help facilitate the growth that is happening in Mohave Valley and serve the members for years to come.”

“We increased capacity by about 70%, which will allow for MEC to meet future load growth in a reliable manner,” added MEC COO Jonathan Martell. “It does also give us the ability to accommodate emergency switching and lessen the impacts of maintenance related outages.”

MEC keeps a redundant path in place for most instances, allowing field crews to “reroute” power supplies should there be an outage. This was most apparent recently when a massive storm caused a widespread outage in Bullhead City and other nearby communities. Crews were able to reroute some of the feeder lines restoring power to members in a more timely manner despite 140 poles being down throughout the area.

The new transformer also has the capability to allow MEC to monitor the health of the transformer in real time. Other upgrades to the substation that were performed include: new potential transformers used for metering and relaying; a new upgraded strain bus to accommodate the upgraded transformer; new bypass switches and upgrades to the grounding grid.

Martell said that the existing transformer will be refurbished and stored so that it may be used in the event of a substation transformer failure. “That could be huge for us,” Martell said. “Instead of waiting for a new transformer to be built, which could take up to a year, and having to push that burden to other substation transformers, via switching, we would have a replacement available.”