Dominion Virginia Power proposes rebuild of existing 500-kV Cunningham–Dooms line

Final review comments regarding the environmental impact of Virginia Electric and Power’s (Dominion Virginia Power) proposed rebuild of an existing 500-kV line will be submitted to the Virginia State Corporation Commission (SCC) by May 16, the Virginia Department of Environmental Quality said on March 17.

Dominion Virginia Power is planning to rebuild, entirely within its existing right of way (ROW), about 32.7 miles of its existing 500-kV Cunningham–Dooms Line #534 transmission line in Fluvanna, Albemarle and Augusta counties, the company said in its March 2 application filed with the SCC.

The line runs between the company’s existing Cunningham switching station in Fluvanna County and its existing Dooms substation in Augusta County.

The entire existing transmission corridor consists of existing transmission easements in continuous use since the 1964-1966 original construction timeframe, the company added. The existing ROW contains multiple circuits and varies in width from a minimum of 150 feet to a maximum of 292 feet, the company said, adding that no new easements would be required for the rebuild project.

The existing line traverses Augusta County for about 4.2 miles, Albemarle County for about 25.1 miles and Fluvanna County for about 3.4 miles. Shenandoah Valley Electric Cooperative (SVEC) is the service provider for about 2.2 miles of the existing corridor in Augusta County; Central Virginia Electric Cooperative (CVEC) is the service provider for about 15 miles of the existing corridor in Albemarle and Fluvanna counties; and American Electric Power’s (NYSE:AEP) Appalachian Power Company (APCo) is the service provider for about 6.6 miles of the existing corridor in Albemarle County. About 18.9 miles of the existing corridor are located within Dominion Virginia Power’s own service territory. The company added that SVEC, CVEC and APCo do not object to the proposed rebuild of the existing transmission facilities.

The in-service date for the rebuild project is anticipated to be summer – starting June 1 – of 2019, and the estimated total cost of the project is about $59m, of which about $58.5m is for transmission line construction work. The estimated cost of work at the Cunningham station is $245,000, and $246,000 at the Dooms substation. The company added that those costs estimates are in 2015 dollars.

Dominion Virginia Power said that the rebuild project is necessary to assure that the company can continue to provide reliable electric service consistent with mandatory NERC reliability standards for transmission facilities and the company’s transmission planning criteria. The company also noted that the line provides service to its transmission system in the western and central regions of Virginia, and is a critical component of the electric transmission grid that serves Virginia, Maryland, West Virginia, the District of Columbia and beyond.

The failure to address the significant inherent corrosion and deterioration associated with “COR-TEN” weathering steel lattice towers will limit the company’s ability to maintain reliable transmission service to its customers, whose load continues to increase, the company said.

From 2013 to 2015, the coincidental summer peak load for the company’s system grew from 18,763 MW to 18,980 MW, an increase of 1.2%, representing an actual compound annual growth rate of 0.38%.

The company also said that the existing 500-kV steel structures supporting the existing line between the Cunningham station and Dooms substation would be removed and replaced with new 500-kV single circuit galvanized steel lattice towers. In addition to the tower and line replacement, existing 2-2049.5 bundled AAAC conductors of Line #534 would be replaced with three triple-bundled 1351.5 ACSR phase conductors.

The company added that the proposed rebuild project has been reviewed through the PJM Southern Subregional Committee as well as the PJM Transmission Expansion Advisory Committee, and was approved by the PJM Interconnection Board as a PJM baseline upgrade (b2665) last December.

The rebuild project provides the benefit of replacing aging transmission facilities that are reaching the end of their service lives. Line #534, for which construction was completed in 1966 as part of the company’s 500-kV “original loop,” is part of the first 500-kV transmission systems built in North America, the company added.

The line was built with first generation 500-kV technology, and after 50 years of continuous operation, the line and its associated facilities are approaching the end of their service lives and require replacement with new facilities in order to maintain reliable service, the company said.

Among other things, the company said that the proposed facilities would afford the best means of meeting the continuing need for reliable service while reasonably minimizing adverse impact on the scenic, environmental and historic assets of the area.

Dominion Virginia Power is a subsidiary of Dominion Resources (NYSE:D).

About Corina Rivera-Linares 3058 Articles
Corina Rivera-Linares, chief editor for TransmissionHub, has covered the U.S. power industry for the past 15 years. Before joining TransmissionHub, Corina covered renewable energy and environmental issues, as well as transmission, generation, regulation, legislation and ISO/RTO matters at SNL Financial. She has also covered such topics as health, politics, and education for weekly newspapers and national magazines. She can be reached at clinares@endeavorb2b.com.