High Voltage Direct Current
(HVDC)
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Project title
New HVDC Transmission Link from Heritage to Mosby
Project description
Construct a new bipolar ±525kV HVDC transmission link between the Heritage and Mosby Substations. This HVDC link will have a total transmission capacity of 6,000 MW, with 3,000 MW to be implemented in Phase 1, and an additional 3,000 MW planned for Phase 2. Construct two converter stations, one at each substation (Heritage and Mosby), each with a capacity of 3,000 MW. Install a bipolar HVDC transmission line, approximately 185 miles in length, fully routed underground between the two substations.
Project in-service date
06/2032
Conductor Size and Type
The preferred Dominion Energy cable system to be installed is an XLPE cable system, designed to AEIC CS9 standards. Each circuit will consist of schedule 40 PVC conduits encased in concrete.
General route description
The HVDC link starts at Heritage Substation in Freeman, VA and travels north approximately 185 miles to Mosby Substation in Aldie, VA.
Terrain description
This project is approximately 185 miles through the piedmont region. The counties include Greensville, Dinwiddie, Chesterfield, Powhatan, Goochland, Hanover, Caroline, Spotsylvania, Stafford, Fauquier, Prince William, and Loudoun Counties. The areas range from rural, suburban to densely urban. There would be civil infrastructure, wetland and stream crossings to navigate.
Right-of-way width by segment
Existing Dominion ROW to be used for this project. A permanent easement, or Right-of-Way (ROW), is required for each duct bank post installation for operation and maintenance. This easement will primarily be used to limit vegetation, prevent external parties from digging into the duct bank, and to maintain or repair the lines. The physical footprint of the duct banks is assumed to be 8 feet wide. For typical operations and maintenance practice, 15-ft is added to each side of the duct banks. The total permanent new Right-of-Way necessary for the underground cable system would be 40-ft. For trenchless crossings, 150ft of ROW is needed for Horizontal Directional Drilling and 50ft of ROW is needed for Jack and Bore. At locations where splice vaults are required, the ROW will need to expand to 40-ft to accommodate the larger footprint of the system.