Article 691

Large-Scale Photovoltaic (PV) Electric Power Production Facility

  1. The PV source circuit is matched to the voltage ratingand charge current requirements of the interconnected battery cells and,
  2. The maximum charging current multiplied by 1 hour is less than 3 percent of the rated battery capacity expressed in ampere-hours or as recommended by the battery manufacturer
  1. Scope. This article covers the installation of large-scale PV electric power production facilities with a generating capacity of no less than 5000 kW, and not under exclusive util‐ ity control.Informational Note No. 1: Facilities covered by this article have specific design and safety features unique to large-scale PV facili‐ ties and are operated for the sole purpose of providing electric supply to a system operated by a regulated utility for the transfer of electric energy.Informational Note No. 2: Section 90.2(B)(5) includes informa‐ tion about utility-owned properties not covered under this Code. For additional information on electric supply stations, see ANSI/IEEE C2-2012, National Electrical Safety Code.
  2. Definitions.

Electric Supply Stations. Locations containing the generating stations and substations, including their associated generator, storage battery, transformer, and switchgear areas.

Generating Capacity. The sum of the parallel-connected inver‐ ter rated maximum continuous output power at 40°C in kilo‐ watts (kW).

Generating Station. A plant wherein electric energy is produced by conversion from some other form of energy (e.g., chemical, nuclear, solar, wind, mechanical, or hydraulic) by means of suitable apparatus.

  1. Special Requirements for Large-Scale PV Electric Supply Stations. Large-scale PV electric supply stations shall be acces‐ sible only to authorized personnel and comply with the follow‐ ing:ARTICLE 692 — FUEL CELL SYSTEMS 692.2
    1. Electrical circuits and equipment shall be maintained and operated only by qualified personnel.Informational Note: Refer to NFPA 70E-2015, Standard for Electri‐ cal Safety in the Workplace, for electrical safety requirements.
    2. Access to PV electric supply stations shall be restricted by fencing or other adequate means in accordance with110.31. Field-applied hazard markings shall be applied in accordance with 110.21(B).
    3. The connection between the PV electric supply station and the system operated by a utility for the transfer of electrical energy shall be through medium- or high- voltage switch gear, substation, switch yard, or similar methods whose sole purpose shall be to safely and effec‐ tively interconnect the two systems.
    4. The electrical loads within the PV electric supply station shall only be used to power auxiliary equipment for the generation of the PV power.
    5. Large-scale PV electric supply stations shall not be installed on buildings.
  2. Equipment Approval. All electrical equipment shall be approved for installation by one of the following:
    1. Listing and labeling
    2. Field labeling
    3. Where products complying with 691.5(1) or (2) are not available, by engineering review validating that the electri‐ cal equipment is tested to relevant standards or industry practice
  3. Engineered Design. Documentation of the electrical portion of the engineered design of the electric supply station shall be stamped and provided upon request of the AHJ. Addi‐ tional stamped independent engineering reports detailing compliance of the design with applicable electrical standards and industry practice shall be provided upon request of the AHJ. The independent engineer shall be a licensed professio‐ nal electrical engineer retained by the system owner or instal‐ ler. This documentation shall include details of conformance of the design with Article 690, and any alternative methods to Article 690, or other articles of this Code.
  4. Conformance of Construction to Engineered Design. Documentation that the construction of the electric supply station conforms to the electrical engineered design shall be provided upon request of the AHJ. Additional stamped inde‐ pendent engineering reports detailing the construction conforms with this Code, applicable standards and industry practice shall be provided upon request of the AHJ. The inde‐ pendent engineer shall be a licensed professional electrical engineer retained by the system owner or installer. This docu‐ mentation, where requested, shall be available prior to commercial operation of the station.
  5. Direct Current Operating Voltage. For large-scale PV electric supply stations, calculations shall be included in the documentation required in 691.6.
  6. Disconnection of Photovoltaic Equipment. Isolating devices shall be permitted to be more than 1.8 m (6 ft) from the equipment where written safety procedures and conditions of maintenance and supervision ensure that only qualified persons service the equipment.Informational Note: For information on lockout/tagout proce‐ dures, see NFPA 70E-2015, Standard for Electrical Safety in the Work‐ place.
    Buildings whose sole purpose is to house and protect supply station equipment shall not be required to comply with 690.12. Written standard operating procedures shall be available at the site detailing necessary shutdown procedures in the event of an emergency.
  7. Arc-Fault Mitigation. PV systems that do not comply with the requirements of 690.11 shall include details of fire mitigation plans to address dc arc-faults in the documentation required in 691.6.
  8. Fence Grounding. Fence grounding requirements and details shall be included in the documentation required in 691.6.