Virginia Electric and Power Company d/b/a Dominion North Carolina Power (Dominion) is seeking approval to build about 11 miles of a new single-circuit 230-kV transmission line in Currituck County, N.C.
According to the company’s application for a certificate of environmental compatibility and public convenience and necessity filed with the North Carolina Utilities Commission on March 19, the line would go from the company’s existing Shawboro substation and tie into its existing 230-kV Shawboro-Kitty Hawk Line #2073 at a point near the tap that serves the Aydlett substation (Aydlett Tap).
The proposed project will result in the construction of a new third 230-kV line between the Shawboro substation and the Aydlett Tap and the creation of a new 230-kV circuit from the Shawboro substation to feed the Aydlett substation, which will be designated the Shawboro-Aydlett Line #2136.
Dominion also said the estimated total cost to build the proposed project is about $31.3m, of which about $30.8m is for construction of transmission line facilities and about $596,000 is for substation work.
If the proposed project includes relocation of two existing lines near the Currituck County regional airport, the proposed project’s estimated cost would increase by about $12m to a total of $43m, the company added.
Dominion said the proposed project is needed to add capacity to the 230-kV system in the area to assure that the company can continue to provide reliable service to customers in eastern North Carolina, and particularly in Currituck County south of the Shawboro substation, including the Outer Banks, consistent with mandatory NERC reliability standards for transmission facilities and the planning criteria of PJM Interconnection and the company.
Power flow studies done as part of the 2010 PJM regional transmission expansion plan forecast that if the proposed project is not in service by the summer of 2015, starting June 1, either of two different planning scenarios will result in load loss exceeding 300 MW on the company’s transmission system in northeastern North Carolina, violating Dominion and PJM planning criteria and NERC reliability standards, Dominion said.
The studies also project that by the summer of 2017, the outage of Line #2073 results in loading exceeding 94% on 230-kV Line #2064, also violating Dominion and PJM planning criteria and NERC reliability standards.
Dominion said the load it serves in northeastern North Carolina has experienced growth in power demand over the past several years.
“The proposed project will help ensure that Dominion can continue to provide reliable electric service to northeastern North Carolina consistent with mandatory NERC reliability standards for transmission planning and the transmission planning criteria of PJM and the company,” Dominion said.
The existing 230-kV common double-circuit transmission line facilities, composed of Line #2073 and Shawboro-Kitty Hawk Line #2064, constitute the only source of transmission to the area south of Shawboro, including the Outer Banks.
Dominion also said the new line will be installed on single circuit weathering steel monopole structures on a route that will parallel and be located adjacent to the existing double-circuit structures that support Lines #2073 and #2064. While the new line will use the existing transmission corridor, the existing easement will need to be widened by 60 feet to accommodate the new structures, the company said.