The North Carolina Utilities Commission, in an Oct. 12 order, issued to Duke Energy‘s Duke Energy Progress a certificate of environmental compatibility and public convenience and necessity to build about three miles (six circuit miles) of new 230-kV transmission line in Hoke County, N.C.
The NCUC said that it finds that the proposed line satisfies certain environmental compatibility and public convenience and necessity requirements, and that a CPCN should be issued for the proposed line construction.
As noted in the order, Duke Energy Progress in May filed an application for the certificate of environmental compatibility and public convenience and necessity authorizing the construction of the new line, which will create a loop connecting the existing Raeford 230-kV substation with the existing Ford Bragg Woodruff Street—Richmond 230-kV transmission line. The total length of the proposed line is about three corridor miles, or six circuit miles, the order said.
As TransmissionHub reported, the NCUC, in a Sept. 7 order, cancelled an expert witness hearing that was scheduled to take place on Sept. 8 in Raleigh regarding the proposed line. Also, the NCUC issued an order on Sept. 6 cancelling the public witness hearing that was scheduled to be held on Sept. 7 in Raeford. Duke Energy Progress on Sept. 6 filed a motion requesting that the NCUC cancel the expert witness hearing that was scheduled for Sept. 8.
The NCUC said in its Oct. 12 order that Duke Energy Progress and Public Staff filed a joint proposed order on Sept. 28.
The order noted that according to Duke Energy Progress, based on transmission line conditions by summer 2018, if a Brunswick nuclear station unit is offline, a loss of the common tower Fayetteville—Rockingham 230-kV and Fayetteville—Raeford 230-kV transmission lines is projected to cause the Weatherspoon—Raeford 115-kV transmission line to overload.
NERC reliability standards require planning for the loss of any generator plus a transmission line, the order said, noting that such a loss is considered a required N-2 planning contingency. Duke Energy Progress’s reliability criteria considers common tower transmission lines greater than one mile in length to be considered as a single contingency, the order said.
In addition, by summer 2018, losing both of the Raeford 230/115-kV, 200 MVA transformers at the Raeford 230-kV substation is projected to overload the Laurinburg—Raeford 115-kV transmission line. NERC considers that scenario an N-1-1 contingency when a system adjustment is allowed between the two N-1 contingencies.
The system adjustment can include actions such as switching other lines or transformers in or out of service or a generation re-dispatch between the two N-1 contingencies, the order said. In the case of that N-1-1 contingency, no reasonable system adjustment is available to mitigate the resultant overloading, the order said, adding that the proposed project will mitigate each of those contingency scenarios.
According to Duke Energy Progress, the preferred route for the transmission line originates at the Raeford 230-kV substation, located about 0.2 mile north of N. Old Wire Road, and 0.7 mile west of NC State Highway 20. The route exits the substation to the northwest and immediately crosses over the Raeford—Lumbee River 115-kV transmission line before turning southwest for about 315 feet, the order added.
At that point, the route turns northwest and parallels the existing Raeford 230-kV—Raeford 115-kV transmission line for about 0.8 miles, crossing over Gold Hill Road in the process. The route then turns north and extends for about one mile and crosses NC State Highway 20 again, the order added.
The route continues north and crosses the A&R rail line about 350 feet north of the road crossing before proceeding in the same direction for about 0.6 miles and crossing Arabia Road. After extending an additional 980 feet to the north, the route turns northwest, travels about 0.2 miles, and terminates at the Richmond—Woodruff St. 230-kV transmission line tap point, the order added.
The order further noted that according to the company, the proposed in-service date for the new line is summer 2018, and the transmission project will cost about $9.5 million.