Power Grid Failure : Blacking out Truth about Two Blackouts – Prabir Purkayastha



THE Power Ministry and Power Grid — squarely responsible for the failure of the grid on two successive days July 30 and 31 — have been very successful in hoodwinking the media about the cause of such a massive failure. Whether it is the TV channels or the print media, all are parroting what the “experts” in the government are telling them — that an overstrained system, starving of power and indisciplined states overdrawing their share led to the grid collapse. The truth — as we stated in our last week’s article — is quite different. The cause of the grid collapse had nothing to do with over-withdrawals. The grid failed squarely because of grid mismanagement. It is a weak grid to start with, had one major transmission link under outage, and was being used to transfer large amounts of power to meet the requirements of open access for which it had not been designed.

 

Interestingly enough, the grid collapse in the US-Canada system in 2003 was also traced to similar causes. Experts had warned that of grid instability and possibility of blackouts with deregulation (Eric J Lerner “What’s wrong with the electric grid?”, American Institute of Physics).  The grid failure was caused as much by local faults and problems with the transmission network as with creation of power markets that saw large amounts of power being wheeled through the network not designed for carrying it. In the US, it was calculated that savings in lower prices through power markets would amount to about three to five billion dollars, while the cost of upgrading the grid would be of the order of 50-100 billion dollars. Of course, even one blackout costs billions of dollars and nullifies all the “gains” from open access and creating power markets.

PROBLEM WITH THE

SO-CALLED REFORMS

Originally, the grid was intended for transferring power from surplus areas to deficit areas. With “open access” and power markets, any distribution utility can buy power from any supplier, located anywhere on the grid. The result is a much larger flow from one region to the other than if the grid is used only for transferring surplus power from one area to another. We have to convert the existing grids to act as a market place for power transfers also, if there are much larger costs involved. The problem with the so-called power sector reforms is that in encouraging markets and market driven policies, the true costs of reforms are never taken into account. Instead, the policy looks at only the incentives that private capital needs to come in and set up plants; all other costs are of course borne by the people.

Overdrawing by a state — a state drawing more than its share — by itself does not cause a grid failure. If demand is more than supply, the frequency of the grid will fall; if supply is higher than demand, the frequency will rise. We have a regime that allows states to draw more than their share by paying some penalties. Thus, if the frequency is going down, the penalties for withdrawal are heavy, while drawing less under these conditions gives the distribution utilities some bonus. The suppliers have similar penalties and bonuses, but the other way they get a higher bonus for pushing power into the grid when the frequency is falling while getting less when the grid frequency is rising. This is called the Unscheduled Interchange (UI) regime and it has helped to stabilise the grid over the last few years. The states therefore are allowed to draw more than their share if the frequency is within a particular band.

The problem with taking more than the allotted share occurs only if it leads to the frequency of the grid going down below what is safe. If indeed overdrawing is what caused the grid to collapse, we should have seen lower frequencies in the grid before the two collapses. The National Load Despatch Centre has put out “flash” report on the two grid failures. Both of them show that the frequencies before the failures on both days were quite healthy — it was 49.68 Hertz at 2.32 a m on July 30, minutes before the collapse, and 49.84 Hertz at 12.57, again minutes before the collapse. These are indeed very healthy frequency figures. Further, if we examine frequency figures of the grid for a longer period before the collapse, we will again see that the frequency of the grid in this entire period was very good — it was by and large within the 50.0 + 0.2 band, which is the band for the best run grids in the world. Ergo, a huge shortfall of demand over supply did not exist — the talk of the states overdrawing their share of power and causing the grid collapse is pure hog-wash.

WHAT CAUSED

THE GRID TO FAIL

From what The Hindu has reported (Grid collapse: Poor load management, not overdrawing, to blame?, R Ramachandran, August 3, 2012) about the collapse on July 30, the power plants were reducing their supplies to the grid at that time, as there was not enough demand. This is what we would expect to happen. With rains and the fact that early morning loads are obviously much lower than the daily peaks, we would expect to see much lower demand on the grid at that time. The meteorological department also talks of wide-spread showers in North India for that night. So what we wrote earlier is confirmed from various sources — the load on the system was low and the problem of the grid was not caused by the general shortages that exist in the system. Such shortages occur during peak hours — around 10-12 in the morning and around 6-10 p m in the evening, when some over drawing by states takes place. But not at 2.35 a m in the morning!

Shinde, the then power minister, has talked of grid discipline and the Delhi power minister has stated that UP and Punjab were overdrawing while Delhi was underdrawing from the grid on July 31. The Delhi power minister has also raised the issue of the Northern Regional Load Despatch Centre not enforcing grid discipline. If grid discipline is the issue, then underdrawing or overdrawing are both violations. Given that loads on the system had come down due to lower air-conditioning loads in Delhi on July 31, Delhi really had no option but to draw lower amounts of power. If indeed UP and Punjab were drawing more than their share while Delhi was drawing less, UP and Punjab were bailing out Delhi. Otherwise, the system frequency, which was indeed very good on July 31— hovering around 50 Hertz throughout the day — would have gone through the roof!

So what caused the grid to fail, if excess demand over supply was not the cause? A grid can fail if one of its main transmission links/corridors fails and there is a temporary imbalance in the system. We had talked about the Bina-Gwalior line tripping and that causing the cascading trip of July 30. The National Load Despatch Centre (NLDC) has put out an innocuous sounding report titled “Revision in Transfer Capability between Regional Grids.” It details why the grid tripped on two successive days and substantiates what we had said in our earlier report — it was the Bina-Gwalior-Agra line that tripped on two successive days, leading to the two grid collapses. The report says, “In both the disturbances, in the antecedent grid conditions there was heavy power flow on the 400 KV Bina-Gwalior-Agra single circuit section crossing 1000 MW on the single circuit available. (The second circuit was under outage since 28th July 2012 for up-gradation to 765 KV level). A similar incident at 1510 hours on 29th July 2012 had also led to a near miss situation.”

IMMEDIATE

ISSUES

There was a prior warning — a near miss on July 29, in spite of which no action was taken. Second, it was due to one of the circuits being taken out that led to much higher amounts of power flowing through the single circuit then available, overloading it. The implication of this is quite clear — the grid collapse was the inability to plan for the conditions that would arise from taking out one of the Bina-Gwalior-Agra circuits and not taking remedial action even by July 31, when one near miss and one grid collapse had already taken place.

Incidentally, the upgradation of the Bina-Gwalior-Agra circuit from 400 KV to 765 KV level was to have been finished by March 31, 2012. It was a known bottleneck, which has earlier also caused cascading trips in the grid, though not a full-blown grid collapse

Belatedly, the NLDC has now put in a set of measures to safeguard the system from similar collapses. All of them deal with curtailing inter-regional transfers and transfers through critical links. In other words, the NLDC now recognises that open access polices being pursued under the 2003 Electricity Act without taking into account the capabilities of the transmission network, poses risks to the grid.

While the NLDC has talked about restricting the inter-regional flows and the need to restrict it, there is also another institutional issue here. Before the reforms ushered in under the Electricity Act of 2003, the Regional Load Despatch Centres (RLDCs) and the National Load Despatch Centre were under the Central Electricity Authority and worked with the Regional Electricity Boards.

Though the Regional Electricity Boards were not envisaged under the Electricity Act of 1948, nevertheless being a body consisting of State Electricity Boards (SEBs), which themselves were statutory bodies, their decisions were generally accepted by the SEBs. In any case, CEA had the necessary powers so that the RLDCs could exercise regulatory authority over the SEBs in terms of grid discipline.

With the 2003 Act coming into being, the RLDCs and the NLDC have been transferred to the Power Grid Corporation. With this change, the RLDCs and NLDC are now part of a public sector undertaking. Power Grid’s task is to put up and operate the grid — it does not have the legal authority to discipline the utilities. The task of disciplining the utilities — either generation or distribution — is a regulatory task and cannot be done by a commercial organisation which also enters into transactions with the utilities. In fact, it earns more money if it wheels larger amounts of power; its commercial interests are directly opposed to restricting flows through the grid.

Unfortunately, those who believe that markets solve all problems, do not understand that grid stability depends on supply and demand being in balance every second of the time. This real-time management of the grid is not what any market can do; it demands physical control of the grid and, if need be, cutting out certain loads and supplies. This needs separation of the RLDCs and NLDC from the Power Grid Corporation and put back under the CEA to perform their regulatory role.

We have been critical of the reforms of the power sector, which has been driven by the markets-know-best vision of the power sector. We have pointed out time and again that market driven reforms would not work in the power sector for a variety of reasons, one of them being that electricity has to obey the laws of physics, which are not necessarily in conformity with the market. In spite of repeated failures, no attempt is being made to take stock of the direction of the reforms itself. If we want the power sector to survive, that is what we need to do, there must not be any more of the same failed policies.

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