Standards and References
1.3.1 Standards
Standards are technical documents that allow the manufacturer to develop equipment to meet the majority of user applications, and users to specify equipment that meets their needs in most cases. There are always circumstances that fall outside typical cases covered by standards, but they are few. Although there are many national and regional standards, the primary standards that apply to GIS are the International Electro‐technical Commission (IEC) and the Institute of Electrical and Electronic Engineers (IEEE) standards. In recent years, great effort has been made to harmonize these standards. This effort continues, but differences between them remain. These reflect the differences in the nature of systems, applications, and practices between different parts of the world.
Gas‐insulated switchgear, components, and related equipment fall under a large number of standards. Both IEC and IEEE have standards for GIS, circuit breakers, switches, bushings, testing, instrument transformers, controls, cabinets, pressure vessels, and so on. The difference in the equipment built under the two sets of harmonized standards is small and an understanding of how the equipment is designed and tested can usually allow the user to specify equipment under either set of standards. Most manufacturers design the equipment to meet either set of standards, but often limits on testing capability or cost can leave some areas covered by one set of standards only. This requires review of the application requirements and the tested performance of the equipment to determine if it meets the requirements. There has been, and continues to be, efforts made in the standards community to harmonize the requirements between IEEE and IEC. For high‐voltage GIS, efforts on 62271‐203 (2020) and recently C37.122 (2021) have resulted in a high level of harmonization. Progress has also been made on high‐voltage circuit breaker standards, but here many differences remain. Still, by understanding the differences, a user can use either standard.
An example of differences between IEEE and IEC GIS standards is in North America, where safety requirements for maintenance personnel mandate a visible check to verify that the circuit is not energized before it can be approached for maintenance. This requires a view port or camera to verify the disconnect switch blade position. In other countries, safety requirements allow verification of the position of the disconnect switch linkage as confirmation that the switch is open, kinematic chain.
There are standards other than IEEE and IEC that cover requirements related to GIS, for example, the American Society of Mechanical Engineers (ASME), the American Society for Testing and Materials (ASTM), the European Committee for Electrotechnical Standardization (CENELEC), European Standards (EN), the National Electrical Manufacturers Association (NEMA), to name a few.
1.3.2 Current Standards Most Relevant to GIS
The following is a list of the most relevant standards that may be used for specification of a GIS. This list was developed in 2012 and revised in 2020. Historically, standards can be withdrawn or their numbering changed, but usually only every decade or so.
1.3.2.1 General
IEEE C37.122: IEEE Standard for Gas‐Insulated Substations
IEEE C37.123: IEEE Guide to Specifications for Gas‐Insulated, Electric Power Substation Equipment
IEEE C37.122.1‐2014: IEEE Guide for Gas‐Insulated Substations Rated Above 52 kV
IEEE C37.24: Evaluating the Effect of Solar Radiation on Outdoor Metal‐Enclosed Switchgear
IEC 62271‐203: Gas‐Insulated Metal‐Enclosed Switchgear for Rated Voltages above 52 kV
IEC 62271‐1: High‐Voltage switchgear and controlgear Part 1: Common specification for alternating current switchgear and controlgear
IEC TS 62271‐5 ED1: High‐voltage switchgear and controlgear – Part 5: Common specifications for direct current switchgear
CIGRE Brochure 125: User Guide for the Application of Gas‐Insulated Switchgear (GIS) for Rated Voltages of 72.5 kV and Above
1.3.2.2 GIS Enclosures
In some jurisdictions in the United States, local building codes require the use of the following standards for GIS enclosures:
ANSI/ASME B31.1: Power Piping
The ASME standards are not specifically intended for use for electrical enclosures, but are required in local building codes and are therefore relevant.
In Europe and in Canada, the standards developed by the European Committee for Electrotechnical Standardization (CENELEC) for GIS enclosures are commonly used:
CENELEC EN 50052 (2017): Specification for Cast Aluminum Alloy Enclosures for Gas‐Filled High‐Voltage Switchgear and Controlgear
CENELEC EN 50064‐1989 (2017): Specification for Wrought Aluminum and Aluminum‐Alloy Enclosures for Gas‐Filled High‐Voltage Switchgear and Controlgear
CENELEC EN 50069 (2019): Specification for Welded Composite Enclosures of Cast and Wrought Aluminum Alloys for Gas‐Filled High‐Voltage Switchgear and Controlgear
CENELEC EN 50089 (1994) revised version in 2022: Specification for Cast Resin Partitions for Metal‐Enclosed Gas‐Filled High‐Voltage Switchgear and Controlgear
In other regions, often other standards are in place for GIS enclosures.
1.3.2.3 GIS Systems Above 52 kV
IEEE C37.122: Standard for High‐Voltage Gas‐Insulated Substations Rated above 52 kV
IEC 62271‐203: High‐Voltage Switchgear and Controlgear – Part 203: Gas‐Insulated Metal‐Enclosed Switchgear for Rated Voltages above 52 kV.
1.3.2.4 Gas‐Filled Bushings
IEEE Std. C37.017: IEEE Standard for Bushings for High‐Voltage Circuit Breakers and Gas‐Insulated Switchgear
IEC 61462: Composite Hollow Insulators – Pressurized and Unpressurized Insulators for Use in Electrical Equipment with Rated Voltage Greater than 1000 V – Definitions, Test Methods, Acceptance Criteria, and Design Recommendations
IEC 62155: Hollow Pressurized and Unpressurized Ceramic and Glass Insulators for Use in Electrical Equipment with Rated Voltages Greater than 1000 V
IEC 60507: Artificial Pollution Tests on High‐Voltage Insulators to be Used on a.c. Systems
1.3.2.5 Common Clauses for Switchgear
IEEE Std. C37.100: IEEE Standard Definitions for Power Switchgear
IEEE Std. C37.100.1: IEEE Standard of Common Requirements for High‐Voltage Power Switchgear Rated above 1000 V
IEC 62271‐1: High‐Voltage Switchgear and Controlgear. Part 1: Common Specification
1.3.2.6 Sulfur Hexafluoride (SF6) Gas
ASTM D2472‐00: Standard Specification for Sulfur Hexafluoride
IEC 62271‐4 ED2: High‐voltage switchgear and controlgear – Part 4: Handling procedures for gases and gas mixtures for interruption and insulation
IEC 60376: Specification of Technical Grade Sulfur Hexafluoride (SF6) for Use in Electrical Equipment
IEC 60480: Guidelines for the Checking and Treatment of Sulfur Hexafluoride (SF6) Taken from Electrical Equipment and Specification for its Re‐use
1.3.2.7 High Voltage Testing on Control Systems
IEEE Std. C37.90.1: Surge Withstand Capability (SWC) Tests for Relays and Relay Systems Associated with Electric Power Apparatus
IEC