Frequently Asked Questions

Q. What makes up the Duke Energy transmission system in the Carolinas?
A. Duke Energy’s transmission system in the Carolinas is comprised of power lines needed to deliver safe, reliable electricity to more than 2 million customers in North Carolina and South Carolina. Approximately 13,000 miles of transmission lines and 260 transmission stations operate on four major voltage levels - 500 kilovolts (kV), 230 kV, 100 kV and 44 kV.

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Q. How is Duke Energy connected to the grid?
A. Duke Energy connects its transmission system with eight adjacent utilities via interconnects—Progress Energy, American Electric Power, Tennessee Valley Authority, Southern Company, Yadkin Inc. (an affiliate of Alcoa, Inc.), Southeastern Power Administration (markets power from federally owned and operated hydro facilities), South Carolina Electric & Gas and Santee Cooper.

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Q. Who operates Duke Energy’s transmission system?
A. Highly experienced and trained Duke Energy employees operate the system. Prospective system operators must pass a standardized exam to receive certification. This exam is developed by the North American Electric Reliability Council (NERC). Ongoing operator training and operator certification programs ensure qualified employees operate Duke Energy’s system. Classroom training, comprising “lessons learned” reviews of actual case studies, simulation of real time scenarios, power system operations technical training, standards and operating procedures, is conducted monthly. Training also includes programs and assignments to enhance human performance, communications and interpersonal skills.

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Q. How does Duke Energy ensure reliable, safe electricity for customers?
A. Duke Energy follows an extensive preventative and predictive maintenance program, which is based on careful evaluation, regular inspections and technological enhancements. Employees use helicopters to visually inspect the entire transmission system and right-of-way corridors at least twice each year during the fall and spring. Additionally, employees identify and resolve interferences or potential concerns and conduct inspections during planned maintenance activities, line upgrades and outage restorations. Line performance histories assist crews in evaluating the need for line equipment maintenance or enhancement. Duke Energy invests between $90 and $130 million annually in transmission projects for maintenance, upgrades and new construction in the Carolinas.

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Q. How does Duke Energy know when to add to its transmission infrastructure?
A. Duke Energy uses a comprehensive planning program to identify improvements and/or additions needed for its transmission system—before the customer is impacted. A dedicated system planning group reviews current and projected population growth patterns, customer usage trends and system needs. Based on this information, plans are developed and areas defined for new transmission service.

A sophisticated siting process that includes property-owner input is then implemented and new lines are built. The siting process or study for each expansion project uses cutting-edge technology to integrate environmental, engineering, real estate, socio-economic and regulatory requirements at the onset of the project.

This study uses a systematic process providing identification of relevant issues affecting siting decisions such as, but not limited to, cultural, aesthetic, land use and environmental factors. County records, population studies, geographical surveys and many other land references are reviewed, maps are created and the public is notified and invited to provide input that would assist with selecting the best possible route with the least possible impact.

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Q. How secure is Duke Energy’s transmission system?
A. Duke Energy maintains comprehensive security plans that include oversight by highly trained security professionals and tested, proven communications connections with other utilities and local, state and federal authorities. These plans are evaluated and exercised on a regular basis. Duke Energy is unable to disclose the specifics of its security program since this would compromise its effectiveness.

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Q. How about cyber-terrorism? Or, computer virus impacts?
A. If a utility were affected by a virus, it likely would not place the grid at risk for the following reasons:

  • The system affected may be an information communication path that does not have direct impact to the control of the transmission system and other communications systems are available.
  • Duke Energy’s Supervisory Control and Data Acquisition System (SCADA)—a transmission control system—is protected by firewalls and intrusion detection systems. Intrusion detection devices designed specifically for the SCADA system are monitored continuously.
  • Should any disconnect from the Internet occur, additional independent connections and other backup systems are in place.

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Q. What is SERC?
A. Duke Energy is a member of Southeastern Electric Reliability Council (SERC), one of the 10 regional councils within the North American Electric Reliability Council (NERC). These councils work together to ensure that the bulk electric system in North America is reliable, adequate and secure. Through this voluntary approach, NERC has helped to make the North American bulk electric system the most reliable in the world. Duke Energy believes that consistent practices benefit utilities and their customers and is diligent in its participation and compliance with all of these groups.

The SERC Region is the largest of the NERC regions based on total generation and total load, covers an area of about 464,000 square miles and includes parts or all of 13 southeastern and south central states. The SERC Region is divided into four diverse sub-regions:

  • Entergy (the geographical area of the Entergy Operating Companies and Associated Electric Cooperative, Inc.)
  • Southern (the geographical area of the Southern electrical system)
  • TVA (the Tennessee Valley Authority area)
  • VACAR (the Virginia-Carolinas area)

Duke Energy’s grid in the Carolinas is part of the VACAR sub-region.
SERC member systems pursue aggressive planning and operations through:

  • addition of a conferencing center to facilitate reliability, hotline calls, daily reliability coordinator calls, other member communications
  • annual emergency plan coordination seminars
  • annual system operator conferences
  • databases for transmission and generation outage coordination
  • regional procedures and plans, emergency assistance procedures, regional restoration plans
  • participation in numerous, ongoing intra-regional and inter-regional analyses of projected operating conditions and long-term assessments of the reliability of the transmission system

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Q. What is NERC?
A. The North American Electric Reliability Council (NERC) is made up of 10 regional councils and monitors all participating utilities located in the geographic areas of Canada, the U. S. and a small portion of the Baja California Norte, Mexico. Its mission is to ensure that the bulk electric system in North America is reliable, adequate and secure. NERC was formed in the wake of the 1965 Northeast blackout. NERC monitors and provides guidance to all North American power grid systems regarding reliability and security.

North America’s transmission systems are divided into four regional grids:

  • The Eastern Interconnection - connects the Eastern Seaboard, the Plains and the Eastern Canadian provinces
  • The Western Interconnection - connects the Pacific Coast, the Mountain states and Western Canadian provinces
  • The Texas Interconnection (ERCOT)
  • The Quebec Interconnection - Quebec and the Canadian Maritime Provinces
    Duke Energy’s grid in the Carolinas is a part of the Eastern Interconnection.

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Q. What is VACAR?
A. Duke Energy voluntarily participates in the Virginia Carolina Reliability Group (VACAR), which is a subset of the Southeastern Reliability Council (SERC). Duke Energy serves as the reliability coordinator for VACAR South. VACAR South utilities include Duke Energy, Yadkin Inc. (a part of Alcoa), Santee Cooper, SEPA (Southeastern Power Administration), and SCE&G. VACAR North utilities include Progress Energy and Dominion Resources. Note: the City of Fayetteville, NCEMC, and NCMPA participate as well and are in both the North and South VACAR groups.

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Q. Who regulates Duke Energy’s transmission system?
A. The provision of retail electric service is regulated by the states. Transmission of electricity in interstate commerce is regulated by the Federal Energy Regulatory Commission.