They will be set up at Korattur, Manali, Sholinganallur and Guindy with funding from JICA

Chennai will receive more electricity in a few years with four high-capacity sub-stations being planned in the city.
Now, the city and its neighbouring areas account for 3,000 megawatt (MW), equivalent to one-fourth of the State’s average demand of 12,000 MW. The figure is likely to go up in the coming years.
These substations, to be set up at Korattur, Manali, Sholinganallur and Guindy, will form part of the Japanese International Cooperation Agency (JICA)-aided project. Of the project cost of Rs.5,000 crore, the JICA gives Rs. 3,500 crore in assistance, with the rest coming from the Tamil Nadu Transmission Corporation, an official says. “Associated transmission lines will also be laid.”
Better power flow
Each station, with a capacity of 400 KV (kilovolt), will ensure better power flow to load centres, besides helping to achieve stability in grid operation. All the substations will be commissioned by 2017.
At present, there are four such stations, but all of them are located on the outskirts of the city: Sriperumpudur, Sunguvar Chatram, Almathi and Kalivandapattu.
One more in Pulianthope
Going by the rule of thumb that one 400-KV station handle the load of 750 MW, the new stations will take care of 3,000 MW. If this were to be added to the existing stations, the total will go up to 6,000 MW. Furthermore, one 400-KV station has been planned at Pulianthope, and this will be outside the JICA programme. Another in the city is also being proposed, the official says, hoping that these stations, once commissioned, will meet the requirements for 10 years.
As part of the JICA programme, there will be one more 400-KV substation, which will come up at Karamadai, on the outskirts of Coimbatore.
Also, fourteen 230-KV substations will be established across the State, one-half of which will be in southern districts.
Transmission projects
On the status of the three major transmission projects, the official says one linking Kayathar in Tuticorin district with Sholinganallur, and another linking Tiruvalam in Vellore district to Mettur in Salem are expected to be commissioned in the next few months.
The project to link Thappagundu in Theni district to Salem is likely to go on steam by June 2015. While the Kayathar-Sholinganallur line is likely to be ready in a few weeks, work on the Tiruvalam-Mettur line will be completed by June. These projects are estimated to cost Rs. 4,450 crore.
The Kayathar-Sholinganallur and Thappagundu-Salem projects are essentially meant for renewable energy. Each line is capable of evacuating at least 2,000 MW, the official adds.