Power blackout: Can National grid prevent a 2012 repeat?

Government and sector officials rule out any grid crisis as robust system in place

The sweltering July in 2012 with a weak monsoon was like just another but the 30th and 31st of the month went down in history as literally the darkest days for the country. Power blackout gripped 70 per cent of India and was a wake-up call for power system operators, regulators and policymakers.

Power Grid Corporation of India (PGCIL) and Power System Operations Company (Posoco) were the key entities asked to overhaul the power transmission and management systems, with deadlines ranging from a month to a year. PGCIL claims to have met 98 per cent of the recommendations; the others being long-term plans and to be concluded soon.

In 2012, overloading due to high demand and subsequent overdrawal by Uttar Pradesh snagged the northern grid for multiple states and Union Territories (UTs) — Punjab, Rajasthan, Haryana, Himachal Pradesh, Uttarakhand, Delhi and Chandigarh. A ripple effect gripped the western and eastern grids as well. Close to 600 million people were left guessing in the dark.

Rail services were the first to be hit, with passengers stranded across stations in the north. Water supply was next. It was a welcome break for school students, but mayhem for commercial centres, businesses and housewives. Global papers had their front pages painted with the sad state of the electricity sector in India. Media platforms continued their coverage of what was titled a shameful period for the Indian power sector for another week.

Power supply tripped again the next day on 31st, after an initial restoration. Farmers battling a weak monsoon loaded the grid with irrigation pumps and power guzzling urban centres took the demand to as high as 38,000 Mw. The country’s total demand was 110,000 Mw. About 48,000 Mw of consumer load across 21 states and one UT was affected by the grid disturbance on the two days. Then power minister Sushilkumar Shinde moved to the home ministry, with M Veerappa Moily taking charge on August 1. Both denied charges against the Centre, rapping particular states for causing the grid collapse. UP, the state which overdrew, was then ruled by the Samajwadi Party.

While departments across the sector worked in tandem to restore power, the uphill task was to avoid a repetition. A committee set up to investigate the matter had recommendations for a system overhaul. Review of safety, monitoring and power transfer capacity of transmission systems, strengthening of grid and power networks, expanding inter-state transfer capability and scheduling of demand and supply were key suggestions.

Posoco, in its new avatar, says it has eyes on every unit of electricity passing through the grid. Executives involved in the overhaul say the system of scheduling is stringent and those who bypass are not spared. “All the Regional Load Despatch Centres are fully equipped to handle any load and react in real time. The planning is robust and streamlined between all regions,” said a senior Posoco executive. The entity was asked to evolve a contingency load shedding protocol, as well as to better manage outages. Executives say they have achieved this.

Former PGCIL chairman R N Nayak (2011-2015) rules out repetition of such an outage. “Unless sabotage is planned, it is impossible that an outage over such a large area would happen again.” Development of the transmission network, surplus lines through an area, instead of a single one, grid discipline and inter-state connections took pace in PGCIL during the period.

“Transmission growth started in India properly only after 2006. Transmission was never the focus, as it is now. There is a modern system, more awareness and alertness in system operators at the central and state levels. Most importantly, power is cheaper now,” said Nayak.

As of March 2017, the country had inter-regional transmission capacity of 75,050 Mw, expected to be enhanced to 118,050 Mw by 2022. PGCIL operates close to 140,000 circuit km of transmission lines, along with 220 sub-stations with transformation capacity of 292,000 MVA. 

At end-December 2013, the southern region was connected to the central grid by commissioning of the 765-Kv Raichur-Solapur line, achieving a “one nation, one grid, one frequency” aim.

Power demand has not grown at the same pace as generation, which has touched 290,000 Mw, There is a mismatch with transmission planning. Also, most states change their plans on power sourcing or don’t buy at all. This leads to surplus on one network and deficit in another, leading to congestion and differential pricing. The price in the south has touched Rs 11-20 a unit during summers. But, lately, there have been instances of reducing congestion. The government claims the transmission network has grown substantially, to support any growth or demand. Power prices in the spot market have dropped to Rs 2 a unit.

Piyush Goyal, Union minister for power, says there’s no possibility of another blackout. An official in his ministry said: “There is at present no stranded capacity and congestion in the system is also coming down, as transmission availability is improving. At the same time, we want to keep optimum transmission availability.”

Power transfer capacity of the southern region was increased by 625 Mw in December 2016. The aim is to increase it to 18,400 Mw by 2019-20. Its current capacity is 5,900 Mw. For the west to the north, the transfer capacity would be increased to 20,000 Mw by 2019-20. This would correspond to the wind power projects that would be auctioned in this region and upcoming mega solar energy parks.

PGCIL is also working on its largest project, for monitoring and controlling of electricity supply. Called Unified Real Time Dynamic State Measurement, the central transmission utility would install Phasor Measurement Units at all substations and power generating stations. The network will facilitate monitoring of grid events in real time, such as power flow, voltage, backing down, demand and supply sync, etc. This would improve grid reliability, reduce the probability of blackouts and minimise the impact of grid curtailment.