Future Development: Here the next steps in development are explained for GIS.
GIS Specification: Here the rules and conditions for correct specification of GIS are explained.
GIS Monitoring: Here the monitoring systems for control and supervision are explained.
Gas Handling: Here details of correct gas handling when dealing with SF6 are given.
Digital Communication IEC 62271‐3: Here the impact of digital communication in substations is explained.
Revision of C37.122 GIS: Here information of the latest revision of the GIS standard is given.
Moisture Guide: Here information is given on how to monitor and handle the moisture of SF6.
Alternative Gases: Here information is given on alternative gases to SF6 with lower or no global warming potential.
Determining When to use GIS: Here information is given to find the right decision when to use GIS instead of AIS.
Specification Development: Here information is given on how to write a good specification for GIS.
Examples for GIS interfaces: Here information is given on the different interfaces to GIS and how to specify.
Guidelines for GIS: Here information is given on aspects for using GIS based on IEEE C37.122.1.
Guidelines for on‐site tests: Here information is given on how to test GIS after erection on‐site.
Mobile GIS: Here information is given on the use of GIS for mobile substation installations.
Moscow street house project and Toronto Junction Point GIS need case studies for the use of GIS and GIL.
Underground Substations and Special buildings: Here information is given on special applications only possible with GIS.
Condition Assessment: Here information is given on the possibilities to evaluate the condition of GIS after years of use.
Substations Resilience: Here information is given to show the possibilities for a resilience use of GIS in the power network.
Vacuum HV Switching: Here information is given on the use of vacuum switches and circuit breaker for voltages up to 500 kV.
Low Power Instrument Transformers (LPIT): Here information is given for the use of LPIT in GIS and its advantages.
Digital Twin of GIS and GIL: Here information is given of how GIS and GIL can be digitalized.
Offshore GIS: Here information is given on the offshore applications of GIS.
DC GIS: Here information is given on the use of direct current (DC) GIS.
Digital substation: Here information is given on digital substations using GIS.
The last nine topics have not been presented in tutorial until now, they are innovative part of this GIS book.
1.2 Definitions
This GIS Handbook is based on definitions used in IEEE and IEC standards. Some of the most important definitions for better understanding of the book are listed below.
1.2.1 In IEEE and IEC Standards
There are two definitions used in IEC “Gas‐Insulated Switchgear” and IEEE “Gas‐Insulated Substations.” The reason for this, different names for GIS has an historical background, where IEC started in SC 17A to develop circuit breaker standards and later started a new subcommittee SC 17C on high‐voltage switchgear assemblies, so the link was made to switchgear. In IEEE, the substation committee developed standards on GIS in the substation subcommittee, so the link of GIS was taken to substations.
In IEEE C37.122, GIS is defined as follows:Gas‐insulated switchgear (GIS): a compact, multicomponent switchgear assembly, enclosed in a grounded metallic housing in which the primary insulating medium is gas, typically SF6 and which normally includes buses, switches, circuit breakers, and other associated equipment. Also commonly known as gas‐insulated switchgear.Gas‐insulated switchgear enclosure: A grounded part of gas‐insulated metal‐enclosed switchgear assembly retaining the insulating gas under the prescribed conditions necessary to maintain the required insulation level, protecting the equipment against external influences and providing a high degree of protection from approach to live energized parts.Compartment (GIS): A section of a gas‐insulated switchgear assembly that is enclosed, except for openings necessary for interconnection providing insulating gas isolation from other compartments. A compartment may be designated by the main components in it, e.g., circuit breaker compartment, disconnect switch compartment, bus compartment, etc.Partition: Part of an assembly separating one compartment from other compartments. It provides gas isolation and support for the conductor (gas barrier insulator).Power kinematic chain: Mechanical connecting system from and including the operating mechanism up to and including the moving contacts.
In IEC 62271‐203, GIS is defined as follows:Metal‐enclosed switchgear and controlgear: switchgear and controlgear assemblies with an external metal enclosure intended to be earthed, and complete except for external connections.Gas‐insulated metal‐enclosed switchgear: metal‐enclosed switchgear in which the insulation is obtained, at least partly, by an insulating gas other than air at atmospheric pressure.Gas‐insulated switchgear enclosure: part of gas‐insulated metal‐enclosed switchgear retaining the insulating gas under the pre‐scribed conditions necessary to maintain safely the highest insulation level, protecting the equipment against external influences and providing a high degree of protection to personnel.Compartment: part of gas‐insulated metal‐enclosed switchgear, totally enclosed, except for openings necessary for interconnection and control.Support insulator: internal insulator supporting one or more conductors.Partition: support insulator of gas‐insulated metal‐enclosed switchgear separating one compartment from other compartments.
Note 1 to entry: A compartment may be designated by the main component contained therein, e.g., circuit‐breaker compartment, bus bar compartment.
1.2.2 Gas‐Insulated Metal‐Enclosed Switchgear
Metal‐enclosed switchgear in which the insulation is obtained, at least partly, by an insulating gas other than air at atmospheric pressure, as defined in IEC 62271‐203. This term generally applies to high‐voltage switchgear and controlgear. Three‐phase enclosed gas‐insulated switchgear applies to switchgear with the three phases enclosed in a common enclosure.
Single‐phase enclosed gas‐insulated switchgear applies to switchgear with each phase enclosed in a single independent enclosure.
1.2.3 Compartment of GIS
A section of a gas‐insulated switchgear assembly that is enclosed except for openings necessary for interconnection provides insulating gas isolation from other compartments. A compartment may be designated by the main components in it, for example, circuit breaker compartment, disconnect switch compartment, bus compartment, and so on, as defined in IEEE C37.122.
A compartment of GIS as defined in IEC 62271‐203 as part of a gas‐insulated metal‐enclosed switchgear is totally enclosed, except for openings necessary for interconnection and control.
A compartment may be designated by the main component contained therein, for example, circuit breaker compartment or bus bar compartment.
1.2.4 Design Pressure of Enclosures
The maximum gas pressure to which a gas‐insulated switchgear enclosure will be subjected under normal service conditions, including the heating effects of rated continuous current, as defined in IEEE C37.122.