The Hindu Business Line : Northern Grid to be synchronised in Sept

The stage is set for the synchronisation of the country's largest and most power-deficit grid — the Northern Grid — with the Eastern, North-Eastern and Western Grids from September.

The attempt to synchronise operations in four of the country's five regional grids was prompted by a need to ramp up the interconnection between the Northern and Eastern Grids for transferring up to 1,000 MW surplus power from the eastern region to the energy-deficit northern region, mainly with the Tala project, beginning to flow in from Bhutan to northern States through the Eastern Grid. Also the transfer of electricity from the first stage of NTPC Ltd's Kahalgaon-2 station, located in the eastern region, but whose power has been allocated to the northern region, would be possible with the synchronisation of operations.

Grid Security

However, with the prospect of the four regions operating together in synchronisation, apprehensions of any potential grid indiscipline endangering the grid security in all the four regions have prompted the grid managers to stipulate measures such as a blanket ban on bypassing of under frequency relays (UFRs) in the regions, Government officials involved in the exercise said.

Concerns regarding possible overdrawal of power by the electricity-deficit Northern and Western Grid constituents have also prompted preventive measures such as raising UFR settings in both the regions from the permissible lower limit of 49 hertz to 48.8 hertz to delay tripping. A differential setting between the eastern region and the northern region has also been mooted to avoid overloading of lines in case of generation loss in the northern region. Adequate spare margin is likely to be maintained on the eastern region-northern region AC link to take care of frequent large contingencies in the grid during real time, officials said.

Precautionary Measures

A meeting of the Member Secretaries of regional power committees of the northern, western and eastern regions and some constituent members of these regions is on the cards to discuss and finalise the precautionary measures, they said.

One unit (170 MW) of Bhutan's Tala hydroelectric project was commissioned on July 31 and the other five units of the 1,020-MW project would also be commissioned shortly, power from which flow to northern States of Uttar Pradesh, Delhi, Punjab, Haryana, Jammu and Kashmir and Rajasthan.