Dominion North Carolina Power: 230-kV conversion project to increase reliability

Virginia Electric and Power Company d/b/a Dominion North Carolina Power (Dominion) continues to work on its proposed Winfall-Trowbridge 230-kV conversion project.

Dominion is rebuilding its existing transmission line between the Winfall substation in Perquimans County, N.C., and the Trowbridge substation in Washington County, N.C., a company spokesperson told TransmissionHub April 10.

About 34 miles of existing 115-kV line is to be rebuilt and upgraded for this project, he said, adding that the current line voltage is 115-kV and the rebuild will enable future conversion to 230-kV.

“Following the extensive damage caused by Hurricane Isabel in 2003, Dominion began making immediate repairs and upgrades to the area’s electric transmission infrastructure,” he said. “These improvements will increase service reliability and provide for projected growth in demand for electricity.”

The project is expected to be completed in May 2014, the spokesperson said, noting that construction activities to upgrade the electric transmission facilities along the corridor over-land are nearly complete.

“The last remaining portion of the line to upgrade is the five-mile span across the Albemarle Sound between Dominion’s existing Edenton and Mackeys substations,” he said. “Dominion has partnered with federal, state, and local agencies to develop a construction plan for this water crossing which includes removing and replacing the existing towers and foundations. Dominion will also make upgrades to six substations along this line.”

The estimated cost to build the project is about $70m, he said.

The company said in a March 30 filing with the North Carolina Utilities Regulatory Commission that it is looking to increase annual revenue through the non-fuel component of base rates by $63.7m, with Jan. 1, 2013, as the proposed effective date for the permanent rate revision.

“A large portion of this increase will recover costs associated with electric generating plants, transmission lines and distribution improvements needed for continuing the high levels of service our North Carolina customers expect and deserve,” the company said.

By itself, the adjustment in non-fuel base rates would increase the typical Dominion North Carolina Power residential bill, for 1,000 kWh of usage per month, by about 20%. However, the company added, it anticipates that adjustments to its fuel cost recovery provisions will offset this increase, resulting in a net change on Nov. 1, 2012, of about 15%.

Current projections indicate that the company will be able to reduce customer fuel charges due to several factors, including warmer than normal weather during the past winter, low natural gas prices and the return to service of the North Anna Power Station following the earthquake-related outage in August 2011. The company also said that it expects to propose these adjustments in its annual fuel filing with the commission this summer.

Taken together, the net effect of these changes would raise the monthly bill for the typical Dominion North Carolina Power residential customer from $103.79 to about $119, effective Nov. 1, 2012.

Since the company’s last base rate proceeding filed in 2010, it has made improvements to the transmission and distribution systems needed to deliver electricity in northeastern North Carolina. The company also said it has added generation resources to ensure it can continue to provide customers with reliable and cost-effective power supplies from a diverse resource portfolio.

About 51%, or $32.8m, of the requested $63.7m increase in non-fuel base rates is needed to recover the cost of this infrastructure, the company added.

Besides the Winfall-to-Trowbridge line, other major transmission projects include the 115-kV Kitty Hawk-to-Nags Head line, which improves service reliability from the Nags Head to the Oregon Inlet sections of the Outer Banks, the company said.

The spokesperson told TransmissionHub that the approximately $14m, 7.3-mile Kitty Hawk-to-Nags Head Second 115-kV line was energized and has been in service since December 2010.

“A second transmission line was needed to provide the necessary reliability to support continued economic growth on the Outer Banks and provide an alternate source of electrical service to the area,” he said. “The second 115-kV line alleviates potential overloading of the existing line and provides an additional transmission source into the area for improved reliability – meaning fewer outages or service interruptions for residents and businesses on the Outer Banks.”

The new line extends east from Dominion’s existing Kitty Hawk substation on North Carolina Department of Transportation (NCDOT) right-of-way on the south side of Route 1206, he said. The single pole structures continue along the eastside of Route 158 on NCDOT right-of-way to the existing transmission structures near the Outer Banks YMCA. The new line then connects with existing structures that continue south along the island, he added.

About Corina Rivera-Linares 3286 Articles
Corina Rivera-Linares was TransmissionHub’s chief editor until August 2021, as well as part of the team that established TransmissionHub in 2011. Before joining TransmissionHub, Corina covered renewable energy and environmental issues, as well as transmission, generation, regulation, legislation and ISO/RTO matters at SNL Financial from 2005 to 2011. She has also covered such topics as health, politics, and education for weekly newspapers and national magazines.