Tennessee public power utility Greeneville Light and Power System has completed a $5 million substation designed to ensure the reliable flow of electricity to its customers in eastern Tennessee.
The main reason for building the new substation was to have a fourth point of connection for bulk power supply to augment Greeneville’s existing three power supply connections with the Tennessee Valley Authority.
“If we lost one substation at peak load, we didn’t have enough capacity to serve all of the load,” Chuck Bowlin, director of operations and engineering at Greeneville Light and Power, said.
The new substation provides for that contingency by increasing delivery point capacity. It also improves routine reliability, Bowlin said.
The new substation is also tied into the utility’s supervisory control and data acquisition (SCADA) system that monitors operations for the substation and allows for the control of equipment remotely.
The substation converts the 161-kilovolt (kV) power feed from TVA down to 69 kV for use on Greeneville’s distribution sub-transmission system. The station also converts some of the incoming power to 13 kV for use with the onsite capacitators. The transformer, at $1.5 million, was the most expensive single piece of equipment in the substation project, Bowlin said.
The new substation was built on a 12-acre site donated by U.S Nitrogen, one of Greeneville Light and Power’s large customers, which also helped the utility acquire needed easements for access. U.S. Nitrogen received no benefits for its contributions other than the system improvements that will benefit all the utility’s customers.
Another Greeneville industrial customer, SumiRiko, along with the county’s Industrial Development Board, helped the utility widen the right-of-way needed for the transmission lines.
TVA line access to the new substation was also aided by the fact that Greeneville Light and Power already owned a 100-foot right-of-way that runs to TVA facilities. The utility acquired the right-of-way from TVA in the 1980s.
So, instead of TVA having to go through the process of acquiring the needed rights-of-way, Bowlin said Greeneville turned ownership of the existing right-of-way over to TVA, enabling them to build their line to the new substation. The project would not have happened without “the help of our partners,” Bowlin said.
In addition, the new substation was designed with expansion in mind. A concrete pad was installed that will allow the installation of another transformer if the need arises in the future and extra room was left inside the control building for additional control panels.
Some of the work on the new substation was done during the COVID-19 pandemic. To maintain social distancing, some workers reported directly to the site where a microwave and coffee machine were installed in the building housing the substation’s control equipment. Those workers lived there for several weeks, Bowlin said.