Design challenges in the 765 kV air insulated substation

POWERGRID commissioned its first 765/400/220 kV Air Insulated Substation (AIS) in India at Seoni in 2007. The objective of Power Grid Corporation of India Ltd (POWERGRID) is to create a strong and vibrant National Grid in the country. Establishment of the ultimate National Grid is on fast track and a number of projects are under implementation in this direction. For bulk power transmission across regions in the country, 765 kV and 1200 kV transmission lines have been planned alongwith ±600/±800 kV DC transmission lines. In order to handle bulk power of the order of 6000 MW, techno-economic design of 765 kV substation by careful selection of switchgears and substation materials not only w.r.t reliability but also w.r.t electrical fields, corona,RIV, magnetic field and other aspects for its smooth operation & maintenance assumes significance in this regard. This paper describes various challenges in the techno-economic design of UHV AIS substation and the improvements made based on experience/feedback gained from Seoni substation