CHENNAI: In a major relief to South Indian states, the southern power grid was connected to the national grid on Tuesday evening.The Raichur-Sholapur 765KV single circuit transmission line has been interconnected with the national grid, thereby achieving the one nation-one grid-one frequency system. It cost the Power Grid Corporation Rs 815 crore to set up the system.With this interconnection, the Indian power system entered a new era and became one of the largest operating synchronous grids in the world with about 232GW of installed power generation capacity, said a press release by the Union power ministry.Synchronous integration of southern grid with the rest of the national power grid will not only augment the inter-regional power transfer capacity of the southern region but also relieve the congestion being experienced in a few transmission corridors. This will be a great boost for further economic growth of the country. It might take a few more months before power flow in this line was established, the release said.Power-starved states like Tamil Nadu , Andhra Pradesh and Karnataka were waiting for the line to be interconnected for them to transmit power purchased from surplus states in north and eastern regions. The line has been connected five months ahead of schedule by the Power Grid Corporation of India.Chief minister J Jayalalithaa had written letters to Prime Minister Manmohan Singh blaming the power crisis the state was facing for the lack of a facility to transmit power from private producers in the north as well as states with excess power to the state grid.The inter-connection of the southern grid with the central grid is the last among the regions to be connected to the all-India grid. The north, west, east and north-east regions were connected earlier.“The Sholapur-Raichur line is being connected months ahead of the scheduled date,” director Power Grid Corporation I S Jha told TOI. “In the first month, the line may not transmit power to the full capacity and it will take at least four months before the line becomes fully operational,” Jha said.On the charge that the southern grid is the last to be linked with the central grid, Jha said while the transmission lines were not in proper order in other regions, it was much better in the south. That is the reason for concentrating on the other regions, he said. “Moreover, we expected the thermal as well as the Kudankulam nuclear plant to start generating so that the excess power can be transmitted to other states. But Tamil Nadu became a deficit state due to the delay in commissioning of various power plants,” the director said.A separate corridor to evacuate renewable energy and another transmission line between Chhattisgarh and Pugalur in Karur district is also at the planning stage, according to him.“The interconnection of the southern grid with national grid will declog the transmission line and will enable us to transmit power easily from other states. We hope it is commissioned fully before summer so that we may not have long hours of power cuts ,” said as Tamil Nadu Generation and Distribution Corporation (Tangedco) official, who didn’t want to be identified.