Title - How and Why the Indian Power Grid Collapsed

There is little doubt that it was faulty management by the Northern Grid operator that led to the successive failures and the Eastern Grid and the North Eastern Grid were pulled into the crisis due to no fault of theirs. However India’s oldest private sector operator the 113 year old CESC decoupled from the faltering Grids in time isolating itself from the chaotic breakdown. Supply from CESC plants operating at full steam was back within minutes providing power to both the Calcutta Metro and thousands of its consumers when most of the nation faced a blackout.

The power supply from CESC also proved critical in providing the starting power for quick restoration of the Eastern Grid. What CESC achieved was not rocket science. Load sensors at its synchronizing point at Howrah detected the demand supply imbalance in the connecting WBSEB grid. The Sanjiv Goenka led management was alert enough to isolate itself before being sucked into the demand surge from the northern grid that caused a total collapse. Why sensors and protective relays of the Power Grid at Agra, Lucknow or any other high demand synchronizing point in the Northern Grid did not isolate the demand centers from the grid on Monday night is anybody’s guess. Were the load sensors not operating? Were the protective relays bypassed? Were the Under Frequency Relays out of service? Was the operating staff not empowered to switch off the overdrawing units or whether the overload detection mechanism did not function is a matter that the enquiry would perhaps establish.

Consumers may never know the real reason of the Grid failure but to blame it on the overdrawing State Governments is like accusing gate crashers of spoiling your party when your own security personnel were missing. That comes to the critical point of who ensures Grid compliance, the Power Grid Corporation managing the grid or the State Electric Boards who are being asked to voluntarily play by the rules, but we shall come back to that later.

As per independent reports on Monday night 2.30 p.m. when the first blackout occurred Haryana was overdrawing from the Grid by 25.5% , Uttar Pradesh by 20.8% and Punjab by 5.5% . Over 385 million consumers were blanked out for nearly 12 hours and a smug power minister Sushil Shinde  took credit on its quick restoration next day but not the blame for the Grid failure that he characteristically passed on to the states. On Tuesday afternoon when the Grid failed for the second time all affected generating units of the Northern Grid had not returned and were not functioning at full steam. The power ministry in its anxiety to restore electricity to the consumers  advised drawing from the Eastern and North Eastern grid which was purely a political decision to save face of the Government.

Technology however does not bow to political masters and with the Northern Grid demand supply gap exceeding 30% it collapsed again and brought down with it the Eastern and the North Eastern Grid. It is reported that during the second blackout Haryana was drawing excess power by 22.4% but UP had reduced its overdraw to 6.4% and Punjab to 1.2%. So the excess withdrawal would have been nominal not big enough to really create a massive frequency dip. However since the generating units had not been fully restored the demand supply gap was bigger and the second collapse brought down all three grids resulting in a blackout for 600 million consumers.     

To say that the Grid failure was accidental and the Government was not aware of what was happening is a misnomer. The fat has been on fire since mid June though the reasons of malaise go back even a few months more and is indirectly linked to the excess agricultural load on the system.

As per Central Water Commission CWC data the live water storage capacity measured on 15th June (pre monsoon data) at the Bhakra Beas reservoirs was 16% at Bhakra, compared to 37% last year due to some irrationally heavy withdrawal during early this year. This caused the demand of power needed for sowing to rise during the paddy season. The Punjab State Power Corporation Ltd [PSPCL] revised its demand estimates by 20% within the first fortnight of the season. PSPCL initially attempted to buy more power from outside on a day ahead basis but the load dispatch centre NRLDC imposed constraints did not permit Punjab which is allowed to draw up to 5,100 MW only from outside. As per reports on June 21 PSPCL purchased 750 MW on day ahead basis at Rs.3.84 per unit, but NRLDC allowed transfer of only 450 MW due to transmission constraints.

Similarly UP had estimated that its power demand for the season would be 13,000MW against a local availability of 9500 MW and hence had started implementing unpopular measures to close malls, shops and Cinema halls by 7.00 p.m. by mid June. Doubtless that it would have resorted to buying additional power to satisfy the agriculture demand of the state in a month when monsoon was below expectations. States have the grouse that only Delhi the national capital gets a fair treatment from NRLDC in regularizing the excess buying needs, and they have to resort to overdrawing because they are not allowed to buy extra power.

Over drawing happened regularly during the month of June and July and both the regulator as well as the grid operator was fully aware of the dangers. However instead of taking action to limit excess withdrawal they kept on issuing missives to state Governments to stop excess withdrawal like a schoolmaster pleading with errant students. It is true that there is no Automatic Demand Management System in place still in the Northern Grid but the problem was apparent for months and could be dealt with the existing protection devices. 

The Northern Regional Load Dispatch Centre [NRLDC] a wholly owned subsidiary of Power Grid Corporation had already recorded in June that frequency on certain days remained below the accepted 49.5Hertz for 70% of the time. A petition on the need to self discipline appears on the NRLDC website that says that on several days the instantaneous frequency in the new grid went below 48.8 Hz which was the setting at which the under frequency relays should have kicked in.

The fact is that the Grid operators and the SEB’s believed that the system could be managed on the brink and would never fail. Everyone believed that fines and higher market driven prices could solve the problem and there was no reason to cut off offending units. However in true Indian tradition nobody would be ready to accept the blame and the enquiry is likely to be pretty opaque and produce no conclusive evidence of negligence. The finger pointing that started initially against SEB’s is likely to subside as negotiations begin to camouflage the truth behind the decision to draw from the Eastern and North Eastern grid that resulted in the bigger and second collapse.

Following ‘The nobody killed Jessica’ precedence it may be even possible  that the enquiry will declare that dangerous and repeated low frequency operation was not a cause of the grid failure and the real reason was other complex technical problems beyond the understanding of the public at large.