How did grid survive? PDF Print E-mail
Tuesday, 31 July 2012 00:53
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Ironically, overdrawal least when grid collapsed

Getting the northern grid up and running within 8-10 hours of its collapsing completely at 2 am on Monday was a bit of a miracle, but the bigger miracle was the grid surviving for so long. Indeed, most expected a collapse in the June peak when grid indiscipline was at its worst. Years of rampant indiscipline, ironically, made the grid collapse when overdrawals weren’t as high and when the grid frequency (below 49.5Hz suggests too much power is being overdrawn) was between 49.8 and 50.2Hz. Even more ironic is the fact that it was just 20 days ago that, in response to the northern regional load despatch centre’s—NRLDC is the grid’s policeman, telling states when to withdraw power and when not to—petition asking states to observe grid discipline, the Central Electricity Regulatory Commission (CERC) ordered states to do so, and to report progress by August 14.


What makes Monday’s grid failure so shocking, albeit after a gap of a decade, is that few lessons have been learnt, that powerful states continue to flout the law, that policemen like NRLDC continue to be bypassed and even the CERC’s orders count for squat. In the last quarter of FY12, for instance, Haryana overdrew 1,116 million units of power, or about 51% more than it was allotted by NRLDC; it was 18% in the case of Rajasthan, 5% for UP and Punjab under-drew power by 1%. But what matters more is when the overdrawal takes place. In Q4, there were 63 times when the grid’s frequency was below the critical 49.5Hz—Haryana overdrew power on 52 of these occasions, Rajasthan did it on 46 occasions and even Punjab did it on 45. NRLDC issued a total of 319 warnings to these four states in this period, but they continued to overdraw—NRLDC pointed this out to CERC which was hearing its case, and CERC issued instructions on May 17 saying this would not be allowed. It asked each of the states to explain why they weren’t obeying NRLDC’s instructions—UP said the time given to it to come up with a reply was too short (!), and Haryana said it couldn’t help this since generators within the state had failed to produce power (due to coal shortages no doubt!). Between May 20-30, NRLDC issued another 285 warnings, to no avail. What’s worse, even if states overdraw from the grid despite NRLDC telling them not to, under-frequency relays (the frequency falls when states overdraw) are supposed to cut them off from the grid (‘islanding’ in jargon)—yet, states routinely remove these relays, which is why CERC told states to “ensure that the Under Frequency Relays are kept in service at all times”. Apart from the obvious problems caused by power and coal shortages, there’s a lot of political economy here as powerful states flout regulations at will. When the next grid collapse happens, don’t wonder why it took place, wonder why it took so long.


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