1200 kV transmission network and development status of 1200 kV technology in India

摘要

Indian Economy is growing in the range of 6%-7% per annum. Electricity is one of the key inputs for such sustained growth. The demand of electricity in India is expected to increase to more than 437GW by 2027 in comparison to the present demand of about 100 GW. The primary energy resources for such massive requirement shall continue to be Coal and Hydro. Coal and Hydro resources are mainly located in Central/Eastern part and Northern/North Eastern part of India respectively whereas the loads are concentrated in the Western and Southern part of the country. This necessitates strong, reliable and long transmission network to transfer electricity to distant geographically spread load centers. Considering the constraint in availability of eco-sensitive Right of Way (ROW), need for minimization of traverse of transmission lines through forest, protection of flora & fauna and keeping in view the public resistance for construction of overhead lines in urban areas, development of high capacity transmission corridor of 1200kV and ± 800kV, 6000MW HVDC system within and across region is being envisaged to enhance the capacity of Indian National Grid. It is envisaged that progressively 1200/765 kV AC and ± 800 kV HVDC would become the main trunk transmission corridor and ± 500kV HVDC/400 kV AC would act as support transmission system. In this paper, the major consideration for the development of 1200kV AC system, outcome of various studies & field trials conducted so far for optimization of conductor configuration, air clearances, corona, and status of development of various equipment and transmission line material has been detailed. This paper also describes in brief the insulation coordination studies carried out including protective margins and major technical parameters being considered for 1200kV equipment such as Power Transformer, Disconnector, Circuit Breaker, Surge arrestor, Instrument Transformers etc.