South Carolina Electric & Gas (SCE&G) on April 11 notified the Public Service Commission of South Carolina that the Graniteville-South Augusta 230-kV Tie Line, originally scheduled to be in service by May 31, 2019, is now planned to be in service by June 1, 2020, as a result of Southern Company’s (NYSE:SO) schedule for completion of its portion of the line.
As TransmissionHub reported, the commission in a November 2017 order, granted to SCE&G a certificate of environmental compatibility and public convenience and necessity for the construction and operation of two 230-kV transmission lines – the Graniteville-South Augusta line and the Urquhart-Graniteville #2 230-kV Line – and associated facilities in Aiken County.
As noted in that order, SCE&G filed its application for the certificate in July 2017.
As indicated in the company’s application, SCE&G’s Transmission Planning studies indicate that the occurrence of certain contingencies will result in heavy electrical loading on the existing Vogtle-Savannah River Site 230-kV Tie Line, a critical Southern Company-SCE&G interconnecting 230-kV Line, as early as 2019.
The commission added that a company witness testified that to prevent future excessive loading conditions on that line, as well as to distribute the flow of power more reliably and evenly into the SCE&G system, additional electrical transmission paths are needed and necessary between Southern Company and SCE&G.
Having considered various alternatives, SCE&G and Southern Company agreed to establish two new Southern Company/SCE&G interconnecting tie lines that will cross the Savannah River and enter South Carolina at SCE&G’s Urquhart Generating Station site. The commission added that in addition to decreasing the power flow on the existing Vogtle-Savannah River Site 230-kV Tie Line and more reliably and evenly distributing the flow of power into the SCE&G system, the new tie lines will increase the transfer capacity for all utilities interconnected to SCE&G’s electrical transmission system.
At a hearing, the company witness testified that the proposed Graniteville-South Augusta line would run from Southern Company’s South Augusta substation to SCE&G’s Graniteville Substation No. 2 in Aiken County along existing rights of way (ROWs) – with the exception of an approximately 0.46-mile segment on the Urquhart generating station site for which SCE&G will dedicate a new 100-feet-wide ROW – and that the portion of that line to be owned and operated by SCE&G and for which a certificate was requested in the application would be about 18.1 miles measured from the first transmission line structure on the South Carolina side of the Savannah River to the Graniteville Substation No. 2.
With respect to the second new line – the Urquhart-Graniteville line – the company witness testified that it would run for about 17.6 miles along existing ROW from the company’s Urquhart substation in Aiken County to the company’s Graniteville Substation No. 1 in Aiken County. The commission added that the associated facilities to be added to SCE&G’s transmission system – that is, the 230-kV line terminal and the 230-kV power circuit breaker at the Graniteville Substation No. 1, will accommodate the Urquhart-Graniteville line.
The witness concluded that the proposed lines and associated facilities are critical to the operational integrity of SCE&G’s electrical transmission system, are necessary to ensure that the company’s system remains in compliance with NERC standards and its own long-term planning criteria, and represent the most cost-effective proposal in light of system needs and constraints and the best long-term solution for the continued transmission of safe and reliable electric power to SCE&G’s customers, the commission added.
In its April 11 filing, SCE&G said that at present, it expects the construction of its portion of the Graniteville-South Augusta line to be substantially complete by May 31, 2019, with only the pulling of the last span of conductor from the last SCE&G pole to the first Southern Company pole left to be completed.
SCE&G said that it is planning to install an additional 1% series reactor set on the SRS – Vogtle 230-kV Tie Line to ensure continued compliance with the NERC transmission planning standards until the Graniteville-South Augusta line is in service.
The company also said that the Urquhart-Graniteville line remains on schedule.
A SCANA (NYSE:SCG) spokesperson on April 12 told TransmissionHub that SCE&G expects to complete its Urquhart-Graniteville line work by May 31, 2019.
The total cost for both lines and associated facilities, including incidental projects, is about $30m, she said.
SCE&G is a SCANA company.