A gas-insulated substation (GIS) uses a superior dielectric gas, SF6, at moderate pressure for phase-tophase and phase-to-ground insulation. The high voltage conductors, circuit breaker interrupters, switches, current transformers, and voltage transformers are in SF6 gas inside grounded metal enclosures.

The atmospheric air insulation used in a conventional, air-insulated substation (AIS) requires meters of air insulation to do what SF6 can do in centimeters.

GIS can therefore be smaller than AIS by up to a factor of 10. A GIS is mostly used where space is expensive or not available. In a GIS the active parts are protected from the deterioration from exposure to atmospheric air, moisture, contamination, etc.

As a result, GIS is more reliable and requires less maintenance than AIS.


Purpose: This visit was arranged for 5th semester students who study electric power system-2 and electrical switchgear and protection as subjects, in their academic curriculum. This visit provided them practical knowledge regarding field of power system and switchgear equipment. They learn all the basics of Transmission system and the fundamental behind using GIS (i.e. Gas insulated substation). They also learned that the increasing substation units in city area. A Visit was successful to increase student’s vision towards Power system and Gas Insulated Substation.


Total no of students: 22 (EE)

Date of Visit: 19th August , 2017

Faculty member: Prof. Dimple Dhagiya (EE – SDS)




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