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Gas Insulated Switchgear and GIS Substation Essentials

There is a continuous increase in the application of Gas Insulated Switchgear (GIS) into Electric Power Transmission substations. The superior dielectric and arc quenching properties of SF6 gas allow a substantial reduction in the size of the switchgear and GIS substations can therefore be smaller than conventional air-insulated substations. Enclosed active parts within GIS can also increase the reliability and safety of GIS substations.

This course aims to provide an overview of the most technical issues regarding GIS from both a manufacturer and user perspective. It is intended to assist engineers involved in the design, specification, installation, testing and maintenance of Gas Insulated Switchgear and substations. It covers many of the relevant topics in Gas Insulated Switchgear technology and the design and operation of the switchgear elements, circuit breakers, disconnectors and earth-switches.

As a result of attending the course delegates will develop skills that are in short supply and will:

  • Gain a unique technical insight into some of the most critical components on the network
  • Learn key condition monitoring considerations for Gas Insulated Switchgear
  • Understand GIS testing
  • Develop the skills needed to specify and procure increasingly important strategic assets
  • Understand GIS substation earthing and electromagnetic compatibility issues

Day one

Switchgear Fundamentals

  • Current interruption
  • Electrical insulation
  • Electromagnetic forces
  • Thermal behaviour

Elements of Gas Insulated Switchgear

  • Description of main components
  • Switching components: Functions and applications
  • Technical evolution
  • Gas circuit breakers
  • Disconnectors and earth-switches
  • Structural components: Bus-bars and support insulators

High Voltage GIS Substations

  • AIS versus GIS substations
  • Basic GIS substation lay-outs
  • Indoor and outdoor GIS
  • Economics and reliability of GIS
  • Hybrid switchgear as an alternative to GIS substations
  • Special GIS substations: mobile and temporary substations

Applications of Gas Insulated Switchgear in Medium Voltage Substations

The Gas SF6

  • Why SF6?: analysis of fundamental properties and comparison with air and other gases
  • Reaction with the electric arc and decomposition products
  • Humidity and acidity
  • Factors affecting performance
  • Environmental aspects

Day two

Insulation Coordination in GIS substations

  • Basics of insulation coordination
  • Surge propagation in GIS substations
  • Lightning surges
  • Specific switching transients in GIS: Very fast transient overvoltages
  • Effect of GIS transient overvoltages in associated substation plant as cables and transformers
  • Problems associated with bus-bar switching by GIS disconnectors: Arc break-out

Earthing of GIS substations and EMC

  • Particularities of the earthing in GIS
  • Low frequency earthing
  • High frequency earthing: transient ground potential rise (TGPR)
  • Electromagnetic compatibility of the substation: Sources of interference, their influence on the secondary equipment, and decoupling methods

Testing of GIS

  • Type tests and routine tests
  • International standards
  • Temperature-rise tests
  • Mechanical endurance and climatic test
  • High voltage testing
  • Short-circuit testing
  • Internal arc-fault and pressure rise

Condition Monitoring

  • Reliability Centred Maintenance (RCM)
  • GIS condition monitoring
  • GIS insulation monitoring by partial discharge diagnostics
  • Trends in GIS technology Programme may be subject to amendment

Programme may be subject to amendment

View full course schedule


Course duration: 2 days


CPD Information


EA Technology are accredited members of the CPD certification service. This course counts towards your planned CPD requirements.

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