Electric Substation Now Online

Electric Substation Now Online

August 31, 2018

GUC crews erected the steel structures in early 2017.

An important advantage of being a public utility is our record of reliability. Greenville Utilities continually reinvests in its systems to ensure consistent, reliable service for customers, and quick restoration following weather and other emergencies. How do we do this? One big example is investing in redundant systems like our new (and third) electric Point of Delivery Substation on Mills Road, which went into service on August 6th.

What is a Point of Delivery Substation?

Greenville Utilities is a member of and purchases power from the North Carolina Eastern Municipal Power Agency (NCEMPA). NCEMPA purchases its power from Duke Energy Progress. A Point of Delivery (POD) substation is where Duke hands off high-voltage power to GUC. The purpose of the POD is to step down the voltage to a level that is safer and easier to transport to substations throughout our system and ultimately, to our customers.

In all, Greenville Utilities now has three 230-kv (kilovolts) POD substations.  The Main POD (which was our first) is located on Mumford Road, across from our Operations Center. The 230-kv West is on MacGregor Downs Road, and the new 230-kv South is on Mills Road, near Highway 43 South.

Redundancy and Reliability

For a number of years, the Electric Department's long-range planning has recognized the need for additional POD capacity to enhance reliability and support long-term system growth. “One of our goals is to build a transmission loop around Greenville,” said Substation Control Engineer and Interim Electric Distribution Engineer Ken Wade, “and projects like this enable us to do that, making each substation along the loop more reliable.”

Here’s how it works. If the flow of power to one of the three POD substations is lost, power can be re-routed from the other POD substations. This enables our customers to continue to receive power until the problem is resolved and power is restored to the first POD.

Closing the Loop

Greenville Utilities’ 230-kv West at MacGregor Downs was built in 2002, giving our electric system a higher rate of reliability year-round, in addition to providing extra redundancy during storms and other emergencies (like the area’s flood situations from Hurricanes Floyd in 1999 and Matthew in 2016).

As the population in our service area continued to grow, the need for a third POD was identified to ensure reliable service in case one of the other two PODs were to lose power.

The recent construction of the third POD facility on Mills Road was targeted to take advantage of the Duke Energy Progress Greenville-Kinston-Dupont 230-kV transmission line built in 2015, making our system even more reliable. The new 230-kv West was constructed with a single 120 MVA, 230 kV-115 kV step down power transformer, with provisions for a second transformer and other upgrades in the future as needed.

“Now that 230-kv South is online, redundancy has been added to Bells Fork Substation,” said Ken. “Our plan is to complete the 115 kv loop between Simpson Substation and the new POD, which will add redundancy to Simpson.”