Gas Monitoring Systems
Any instrumentation for measuring, indicating, or giving remote warning of the condition or change in condition of the gas in the enclosure, such as pressure, density, moisture content, etc., as defined in IEEE C37.122.
1.2.6 Gas Leakage Rate (Absolute)
The amount of gas escaping by a time unit expressed in units of Pa m3/s, as defined in IEEE C37.122.
1.2.7 Gas Leakage Rate (Relative)
The absolute leakage rate related to the total amount (mass or volume) of gas in each compartment at the rated filling pressure (or density). It is expressed in percentage per year, as defined in IEEE C37.122.
1.2.8 Gas Pass Through Insulator
An internal insulator supporting one or more conductors specifically designed to allow the passage of gas between adjoining compartments, as defined in IEEE C37.122.
1.2.9 Gas Zone
A section of the GIS, which may consist of one or several gas compartments that have a common gas monitoring system. The enclosure can be single‐phase or three‐phase, as defined in IEEE C37.122.
1.2.10 Local Control Cubicle (or Cabinet) (LCC)
A cubicle or cabinet typically containing secondary equipment including control and interlocking, measuring, indicating, alarm, annunciation, and mimic one‐line diagrams associated with the primary equipment. It may also include protective relays if specified by the user, as defined in IEEE C37.122.
1.2.11 Support Insulator
An internal insulator supporting one or more conductors, as defined in IEC 62271‐203.
1.2.12 Partition
Part of an assembly separating one compartment from other compartments. It provides gas isolation and support for the conductor (gas barrier insulator), as defined in C37.122.
A partition as defined in IEC 62271‐203, which is a support insulator of gas‐insulated metal‐enclosed switchgear separating one compartment from other compartments.
1.2.13 Power Kinematic Chain
A mechanical connecting system from and including the operating mechanism up to and including the moving contacts, as defined in C37.122.
1.2.14 Design Pressure of Enclosures
Relative pressure used to determine the design of the enclosure. It is at least equal to the maximum pressure in the enclosure at the highest temperature that the gas used for insulation can reach under specified maximum service conditions. The transient pressure occurring during and after a breaking operation (e.g., a circuit breaker) is not to be considered in the determination of the design pressure, as defined in IEC 62271‐203.
1.2.15 Relative Pressure Across the Partition
Relative pressure across the partition is at least equal to the maximum relative pressure across the partition during maintenance activities. The transient pressure occurring during and after a breaking operation (e.g., a circuit breaker) is not to be considered in the determination of the design pressure, as defined in IEC 62271‐203.
1.2.16 Operating Pressure of Pressure Relief Device
Relative pressure chosen for the opening operation of pressure relief devices, as defined in IEC 62271‐203.
1.2.17 Routine Test Pressure of Enclosures and Partitions
Relative pressure to which all enclosures and partitions are subjected after manufacturing, as defined in IEC 62271‐203.
1.2.18 Type Test Pressure of Enclosures and Partitions
Relative pressure to which all enclosures and partitions are subjected for type test, as defined in IEC 62271‐203.
1.2.19 Rated Filling Pressure pre
Insulation and/or switching pressure (in Pa), to which the assembly is filled before putting into service. It is referred to at the standard atmospheric air conditions of +20 °C and 101.3 kPa (or density) and may be expressed in relative or absolute terms, as defined in C37.122.
1.2.20 Bushing
Device that enables one or several conductors to pass through a partition, such as a wall or a tank, and insulate the conductors from it, as defined in IEC 62271‐203.
1.2.21 Main Circuit
All the conductive parts of gas‐insulated metal‐enclosed switchgear included in a circuit which is intended to transmit electrical energy, as defined in IEC 62271‐203.
1.2.22 Auxiliary Circuit
All the conductive parts of gas‐insulated metal‐enclosed switchgear included in a circuit (other than the main circuit) intended to control, measure, signal, and regulate. The auxiliary circuits of gas‐insulated metal‐enclosed switchgear include the control and auxiliary circuits of the switching devices, as defined in IEC 62271‐203.
1.2.23 Design Temperature of Enclosures
Maximum temperature that the enclosures can reach under specified maximum service conditions, as defined in IEC 62271‐203.
1.2.24 Service Period
The time until a maintenance, including opening of the gas compartments, is required, as defined in IEC 62271‐203.
1.2.25 Transport Unit
Part of gas‐insulated metal‐enclosed switchgear suitable for shipment without being dismantled, as defined in IEC 62271‐203.
1.2.26 Mixed Technologies Switchgear (MTS)
Mixed technology switchgear concerns the following combinations:
AIS in compact and/or combined design
GIS in combined design
Hybrid GIS in compact and/or combined design
As defined in CIGRE Technical Brochure of Study Committee B3 Working Group 20 from November 2008.
1.2.27 Disruptive Discharge
Phenomena associated with the failure of insulation under electric stress, in which the discharge completely bridges the insulation under test, reducing the voltage between the electrodes to zero or almost zero, as defined in IEC 62271‐203.
1.2.28 Fragmentation
Damage to enclosure due to pressure rise with projection of solid material, as defined in IEC 62271‐203.
1.2.29 Functional Unit
Part of metal‐enclosed switchgear and controlgear comprising all the components, as defined