Transmission sector of TANTRANSCO consists of the following network Infrastructure: EHT for a total length of 24,497 Kms. total of 842 substations 95 Substations in and around Chennai have been provided withSCADA and have been integrated into Chennai Distribution and control center (DCC) TANTRANSCO has one State Load Dispatch Centre at Chennai and 3 Sub LDCs at Chennai, Madurai and Erode.

The transmission network expansion is aimed at evolving a national power grid to facilitate free flow of power across regional boundaries, raising the transmission voltage from 230 kV to 400 kV level. In order to evacuate bulk power from one region to another region, there is scope for enhancing the transmission capability to 765 KV level. Tamil Nadu Electricity Board has taken up the indigenous erection of 400 KV substations and lines. Establishment of 765 KV transmission lines is also under investigation.

The Government of India has approved nondiscriminatory open access to the transmission system to all generators for injecting power and to any consumer to carry the power from the point of injection to his load. To augment the power supply, the Government of Tamil Nadu has also permitted third party sale of power produced by IPPs, CPPs & otherprivate power producers through short term Intra-State open access to HT consumers within Tamil Nadu as it will provide an incentive to the generators within the State to produce to their full capacity.

Substations 33kV & above and EHT lines in the existing network as on 31.03.2018