The Journey of Transformer Replacement at Glen Canyon Powerplant
A bird’s-eye view of each of the four, 3-phase generator step-up transformers.
After more than 5 years of hands-on work, the transformer replacement project at Glen Canyon Dam is officially complete. The last of the generator step-up (GSU) transformers to be replaced became fully operational March 1.
"The completion of this impressive project is a great reflection of the many dedicated and highly talented people who have been involved with the project over the years. This project serves as a testament to our collective efforts towards environmental sustainability, with its incorporation of eco-friendly practices and technologies,” said Upper Colorado Basin Deputy Power Office Manager Bob Martin. “It is also a reflection Reclamation’s commitment to its mission of managing, delivering and protecting water in the West. We are incredibly proud of the work we have been able to accomplish here."
The Journey of Transformer Replacement at Glen Canyon Powerplant
Transformers are vital to the success of power production at any powerplant, and Glen Canyon is no different. Step-up transformers take the power generated from the turbines and convert it from a medium voltage of 13,800 volts to a much higher voltage of 345,000 volts. This higher voltage facilitates the efficient transmission of power to various locations, such as local utility districts and ultimately, the nearly 5 million end-use consumers we serve.
In 2010, Reclamation’s Technical Service Center in Denver first began to make design plans for replacement of the transformers, with the goal of creating a more environmentally friendly design. The original transformers were filled with a carbon-based oil to insulate the coils of wires inside the transformer and safeguard the system from short circuiting. This new design employs a more environmentally friendly natural ester oil and significantly reduces environmental risks.
Yellowstone Electric, a Montana-based company was awarded the contract and arrived on site at the end of 2018 to begin preparing to replace the first transformer. In total, the project took nearly 6 years to complete.
The new transformers were manufactured and designed by Siemens Energy and were transported all the way from Vienna, Austria, traveling across the Atlantic, through the Panama Canal, arriving at the port in Los Angeles and finally to their home in Page, Arizona. The final step of the 6,000+ mile journey required these 127-ton transformers to be transported through a 2-mile-long access tunnel through the canyon walls and to the powerplant at the base of Glen Canyon Dam.
Finalizations to the last transformer began in the last weeks of February. TSC engineers worked alongside power office engineer Matt Jackson, Yellowstone Electric’s Ken Hatfield and the Glen Canyon management and engineering staff to conduct final troubleshooting and the final steps of replacement.
This involved bringing power from the switchyard to the transformer to start the 24-hour energizing process, also known as “soaking”. Once the transformer was adequately energized, operators began sending power from the generators to the transformer, slowly increasing the power load throughout the day. Now that the final new transformer has reached full capacity, for the first time in several years, Glen Canyon will have all eight generating units available.
“This significant milestone marks the end of a considerable amount of effort from the Power Office, Acquisitions, the Technical Service Center, Glen Canyon staff and Yellowstone Electric,” said Glen Canyon Field Division Manager Gus Levy. “I think I can speak for all of us when I say that it is a huge sigh of relief to have this project completed, and we have a lot of people to thank for helping us get here."
For more photos of this impressive project, visit https://www.flickr.com/photos/usbr/albums/72177720315418572
