Development of 1200 kV Transformer

To meet the long term power transfer requirements in the country, POWERGRID envisaged 1200 kV AC system as the next transmission voltage level. To meet this objective, POWERGRID took up a joint initiative with CPRI and Equipment Manufacturers to set up a 1200 kV Test Station and an experimental line at BINA Substation in Madhya Pradesh. Several Indian manufacturers are contributing to this initiative for validation of their technology. ABB was offered the opportunity to develop 333 MVA 1150/√3/400/√3/33 kV transformer and 1200 kV circuit breaker for the National Test station.

The specification of transformer was finalised by a working group on UHV transformers which included members from equipment manufacturers. The rating was based on existing manufacturing capabilities and transport constraints. 1000 MVA single phase auto transformer is the maximum rating that could be transported in the country. The 1000 MVA single phase transformer will comprise of three wound limbs in parallel. The capacity of each limb will be 333.3 MVA. Therefore it was decided by all transformer manufacturers and POWERGRID to develop one limb of the commercial transformer as prototype unit to prove the technology. This paper is an attempt to discuss the learning gained from designing and manufacturing the above 1200 kV transformer.