India: smart steps it can take
American grid expert weighs in
Yesterday I plunged into the speculation around the blackout of mind-boggling scale in India. For the columnist, the formula runs: courage + recklessness = just enough knowledge to be dangerous. I suggested that the upshot was the need to make a greater effort to decentralize and add distributed resources and automation.
If you enjoy gloating, you can read my inexpert speculation in "Lights Out for 700 Million?"
Erich Gunther, an IEEE smart grid expert and co-founder, chairman and CTO for EnerNex, made himself available for a brief chat yesterday.
For Gunther, the Indian outage was "not surprising," given what he knew about the grid in India. And, while awaiting analysis and raw data on grid behavior to determine the sequence of failures that must have taken place, he identified immediate and longer-term steps that India might take to prevent a recurrence.
No doubt that would be good news for the government official who on Monday famously declared the blackout affecting 300 million people to be a "one off," only to see Tuesday's blackout affect more than double that number.
News reports suggested several possible causes of the blackout. Because finger-pointing immediately focused on India's northern states overdrawing their allotment of power, I was skeptical. And because the leader of an enquiry into the last historic blackout identified the lack of manual circuit breaking actions (possibly due to political backscratching) my inner cynic thought that reason passed the sniff test.
Gunther declared that a supply-demand imbalance was at the heart of the event. Why?
"It's all related," he told me. "I like to start with the raw data."
Let's just say a bird flew in the window and told Gunther that frequency variations on the order of one-half to three-quarters of a hertz were recorded across the Indian grid. In the United States, he said, frequency variations of one-tenth of a hertz are considered dicey.
"The frequency data clearly showed the frequency going down on both days for both events," Gunther said. "And the frequency went down substantially before showing any `bounce back' produced by the blackout. That's reminiscent of the pattern we've seen in other large blackouts.
"That data reveals that the frequency was allowed to decay quite a bit, indicating a load-generation imbalance before a variety of things tripped off-line. We don't have enough information to know what really started to trip off-line and cause the cascade. That takes a while to figure out. But we've known for some time that India is challenged in providing the load-generation balance.
"In this case, you've got the hottest summer on record. I don't know if any contingencies were in play or not. But a problem they've had for a long time came to the ultimate breakaway."
Aspects of the Indian grid that might have contributed, according to Gunther: a limited number of interconnections for the high-voltage transmission system and load growth from population growth and industrialization. The high degree of unmetered power, i.e., stolen power, contributes to a lack of situational awareness as well.
Gunther then ticked off a list of actions that could help ameliorate India's grid vulnerabilities in the short term. He explicitly acknowledged that, without a detailed knowledge of aspects of India's grid and its management, that some actions he suggested might be long term in nature or mired in political inertia. (I thought it interesting that Gunther did not mention the mindless solution of building more coal-fired power plants.)
First, because India's grid is unreliable, many customers use their own generators for backup power. That's common in the U.S. among large commercial and industrial concerns, but in India the use of backup generation is widespread among all customer classes. An inventory of distributed energy resources (DER) would provide the first line of defense in an overloaded grid, if owners would agree to switch to backup power upon request by grid operators, according to Gunther. Add to that inventory any and all parties that would agree to respond to a demand response event, possibly for incentives.
Non-essential public loads should be identified and prioritized for taking off-line in case of an event. So street lighting would be turned off long before, say, traffic lights lost power.
"System separation" is a strategy that could limit the scale of a blackout, Gunther suggested.
"Call it macro-gridding, if you will," he said.
These steps all might be automated for speed and reliability of response, he added.
Longer term, increasing distributed energy resources would help, but that raises other issues such as cost and complexity, Gunther said. That's true in the U.S. and more so in India.
"The fundamental problem in India is not enough generation," Gunther concluded. "Disconnected generation is widespread. The technology they need—the controls and interconnections—is more expensive than the DER itself."
It all makes for a fascinating case with a global audience. I'm sure we haven't heard the last of it, as analyses take place within India and by outside experts. Stay tuned!
Intelligent Utility Daily