Virginia Electric and Power (Dominion Energy Virginia) earlier this month filed with the Virginia State Corporation Commission (SCC) an application for approval and certification of electric facilities in relation to the company’s proposal to rebuild, entirely within an existing right of way (ROW) and company owned property, about 8.5 miles of existing 115-kV transmission lines.
The lines are the Possum Point-Smoketown Line #18 and Possum Point-Smoketown Line #145, which are located between the existing 115-kV switch yard at the company’s Possum Point Power Station site and the Northern Virginia Electric Cooperative (NOVEC) Smoketown Delivery Point (DP), entirely in Prince William County, Va.
The company added that it would utilize 230-kV design on all but the first 0.7-mile segment originating from the 115-kV switch yard at the Possum Point Power Station site, which would be rebuilt to 115-kV design in order to continue operating the line at 115 kV.
While the rebuild project proposes to build the lines to be capable of operating at 230 kV, operation of the lines would continue at 115 kV until such time as needed to serve the Northern Virginia Load Area, the company said.
Dominion Energy Virginia also noted that the rebuild project is necessary to assure that the company can maintain and improve reliable electric service to customers served by Lines #18 and #145, which have been identified as nearing their end-of-life, consistent with the company’s planning criteria.
The company noted that it submitted the rebuild project in April with the PJM Interconnection Transmission Expansion Advisory Committee (TEAC) for construction at 230 kV and operation at 115 kV. While that is consistent with how the rebuild project was originally submitted to the PJM TEAC in March 2015, and approved as part of the 2015 Regional Transmission Expansion Plan (RTEP), the company resubmitted the project at the PJM Southern Sub-Regional RTEP (SSRRTEP) Committee meeting in February 2016, for construction and operation at 115 kV. However, the company added, the change to 115 kV was not sent to the PJM Board of Managers at that time.
Following the first resubmission to the SSRRTEP in February 2016, in late July 2016, the company’s Energy Management System (EMS) models and PJM started showing load issues on the section of Line #183 between NOVEC’s Sowego and Independent Hill DPs.
The company added that in August 2016, PJM issued a post-contingency local load relief warning (PCLLRW) – which PJM issues to provide advance notice to a transmission owner of the potential for load shed in its area – for the section of 115-kV Line #183 between NOVEC’s Sowego and Independent Hill DPs.
In this case, the company said, the PCLLRW indicated that no generation or switching was available. The company also noted that its preliminary investigation of the loads on Line #183 at the time of the PCLLRW indicates that they reached levels not projected to occur until 2021.
In addition, through its regular discussions with NOVEC, the company was made aware of the potential for a large – approximately 70-MW – block load addition to NOVEC’s Independent Hill DP. While a solution to resolve the load issue on Line #183 has not yet been determined, it could involve a conversion of Line #183 from 115 kV to 230 kV between the Minnieville Junction and the company’s Elm Farm substation, which would in turn likely involve a conversion of either Line #18 or Line #145 from 115-kV to 230-kV operation in order to create a 230-kV Possum Point-Elm Farm-Ox network, the company added.
Such a conversion would be consistent with “prudent utility practice” and the company’s proposed rebuild project. The company also said that while the rebuild project is not capacity driven, it is prudent planning and engineering to design and build new overhead facilities with a 60+ year life expectancy to the maximum level of capacity and flexibility that can be obtained at a reasonable cost for long-term growth.
“This is especially true in Northern Virginia Load Area, where the company has made consistent efforts since at least 2009 to move load off the 115 kV system and convert to 230 kV where appropriate because of the dynamic nature of load growth in the area, particularly block load additions,” the company said.
Given the issuance of the PCLLRW and NOVEC’s potential block load additions, and consistent with prudent utility practice, the company resubmitted the rebuild project in 2017 with the PJM TEAC for construction at 230 kV and operation at 115 kV, as originally submitted and approved in 2015.
The rebuild project as proposed was presented to the TEAC in April, the company added, noting that PJM considered that an informational update since the rebuild project was originally approved for 230-kV construction as part of the 2015 RTEP; no further action or approval of the project is needed from PJM.
Among other things, the company said that the original in-service target date provided to PJM was Dec. 31, 2016. Presuming SCC authorization by March 2018, and the ability to obtain outages, the company anticipates that the rebuild project could be in service by December 2019.
The company added that the estimated total cost of the proposed rebuild project, which assumes completion by December 2019, is about $18.8m (2017 dollars); there is minimal station work at the Possum Point Station associated with the rebuild project totaling about $124,000.