Study of gas insulated substation and its comparison with air insulated substation

This paper basically evaluates the two types of substation namely AIS and GIS on the basis of the life-cycle cost method, reliability, and environmental effects. The problems of very fast transient oscillations (VFTO) faced in GIS and their possible solutions. It substantiates and supports the use of GIS over AIS with an in depth analysis. In the end, HIS (hybrid GIS) has been proposed as a solution to overcome drawbacks of both AIS and GIS and to use the advantages of both in a single system for the best results.