BackCEA submits report on grid failure to govt
Report calls for new planning criteria, more transmission capacities, ‘dynamic compensation’ to boost voltage
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A committee headed by A.S. Bakshi, chairman of Central Electricity Authority (CEA), in its report submitted to the power ministry on the recent blackouts across India has recommended new planning criteria, setting up new transmission capacities and stressed the need for “dynamic compensation" to boost voltage.
On 31 July, the northern grid collapsed, and on 1 August, in a wider blackout, the northern and eastern ones too went down, leaving nearly 620 million people without electricity.
“Dynamic compensation boosts the voltage up when it drops, and when the voltage surges, it holds it. All of this happens in real time. This system is in place at only a few places in the country and there is a need for it given the recent grid failures," a person aware of the report’s finding said, requesting anonymity.
The report blamed the overdrawing of power by northern region states such as Uttar Pradesh, Punjab and Haryana and underdrawing of electricity by the western region states as a reason for the worst grid failure that India has seen.
The committee also stated that with one of the two paths of the Agra-Bina-Gwalior transmission link being under planned shutdown, the variation in electricity demand led to a dip in the voltage.
This dip in voltage, in turn, tripped the critical transmission link and led to a domino effect, tripping other links.
“The problem on the first day started from here. There was an overload with an electricity surge in this line," said another person aware of the report’s content who also didn’t want to be identified.
This affected electricity supplies to states such as Delhi, Uttar Pradesh, Punjab, Haryana, Rajasthan, Uttarakhand, Himachal Pradesh, Chandigarh and Jammu and Kashmir that draw power from the northern grid.
“On the second day, there was the same situation. In addition, two lines linking Madhya Pradesh and Rajasthan also tripped due to overload. In addition, the Rajasthan government’s Suratgarh generation plant also tripped. This resulted in cascade tripping and caused failures across the northern, eastern and north-eastern grids," said the second person cited above.
Load management functions are overseen by the state-owned Power Grid Corp. of India Ltd (PGCIL) and carried out by its subsidiary Power System Operation Corp. Ltd (Posoco). A grid collapse is the worst-case scenario for any transmission utility; if this happens, states that draw power from that particular network go without power. India has five regional grids—northern, southern, eastern, north-eastern and western. All except the southern one are connected.
“India’s transmission planning criteria is still based in 1992-94 when the grid was small. The grid has become large and its problems are also new. There has been a paradigm shift from small system to large system requiring a new planning criteria," said the first person cited above.
The committee is comprised of Balwinder Singh, former special director, Central Bureau of Investigation; S.C. Srivastava of the Indian Institute of Technology, Kanpur; A. Velayutham, member, Maharashtra Electricity Regulatory Commission, PGCIL chairman and managing director R.N. Nayak, Posoco chief executive officer S.K. Soonee, and K.K. Agrawal, member, CEA.
Regional load despatch centres (RLDCs) fall under the purview of PGCIL and are responsible for maintaining grid discipline and supervising optimum scheduling and delivery of electricity in their regions. The country has 33 state load despatch centres (SLDCs), five RLDCs, and a national load despatch centre.
“The protection audit has started and it’s being done by Central Power Research Institute. This is aimed at addressing the faults with under frequency relays (UFRs) that didn’t work and will help in rectifying them. Most of the UFRs of the northern region didn’t work. While warnings were issued to the SLDCs, no SLDC heeded the warning," said the second person cited above.
The independent third-party audit of the protection systems of the states would help in situations such as demand and supply surges and help in preventing grid failure. The eagerly awaited report to be presented in response to the calling attention motion called in the Lok Sabha has also said that UFRs didn’t work, rendering the power system defence plans useless.
UBS Investment Research in a 3 August report said, “It is clear that India needs to step up investment on transmission infrastructure to match the growing power generation capacity. This is virtually impossible if the financial health of SEBs (state electricity boards) remains precarious. This event is a wake-up call for policymakers to address the structural issues in the sector (a mismatch between the cost of power and end-user tariffs, under-investment in T&D)."
India plans to deploy smart grids that will help utilities detect, isolate and correct problems. Northern states such as Delhi, Uttar Pradesh, Punjab, Haryana, Rajasthan, Uttarakhand, Himachal Pradesh and Jammu and Kashmir aim to prevent grid failures such as those that took place by setting up defence mechanisms such as islanding. This would isolate the fallout of a grid disturbance on the national power grid, restricting it to a particular region, or also allow a particular region or essential service to isolate itself in the event of a grid failure. While the eastern grid supplies power to Bihar, Jharkhand, Orissa, West Bengal and Sikkim, the north-eastern grid supplies electricity to Assam, Manipur, Meghalaya, Nagaland, Tripura, Arunachal Pradesh and Mizoram.
PGCIL owns and operates around 95,009 circuit km of transmission lines and has lined up a ₹ 1 trillion capital expenditure for the 12th Plan period (2012-17).
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