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-   -   PM requests 9-min lights-off on 5th April, and to light candles / diyas (https://www.team-bhp.com/forum/shifting-gears/221074-pm-requests-9-min-lights-off-5th-april-light-candles-diyas.html)

Power consumption has gone down drastically, it is not just residential units that consume power, the industries consume a lot more power than all residential unit combined. Office spaces are not consuming power, metro's are not consuming power, industries are not consuming power, so there is no issue with power.
There is no need to introduce new meaning to every single message by PM. It is a move for solidarity. If you can do it, else don't.

Can any experts throw some light on this ? I hope they figure out a solution to this unique challenge ?!?! Sigh..

"On April 5, instead of demand, the danger is of supply surging and disrupting the frequency when Indian switch off lights all at once at 9 pm. This could trip the line, and lead to a blackout. But, assure senior engineers in the sector, it can be handled as they have the time to plan"

https://www.moneycontrol.com/news/co...y-5104731.html

I think that is just a hypothesis. Nothing is going to happen if every one switches of the bulbs for 9 minutes.

Just my gut feeling and layman opinion and I am no expert in this area. We have many other things to worry about currently. :)

There is a major challenge apparently with the call given by our PM for shutdown of 9 minutes at 9pm on 5th April. The power sector is working on warfooting to prevent any untoward incident. Details in the link.

Link

Yesterday I was thinking about the exact same scenario described in this article. To put it in car terms, an electric generator is like a car engine and the power we consume is the load. Unlike cars, the electricity grid does not have brakes. Which means, the generator should not produce more/less power than what is demanded by the load. If it produces less power, some load has to be removed (power cuts) and if it produces more, there are mechanisms to discharge this excess in the form of heat, store in batteries etc. But there is a limit to how much excess can be safely stored/discharged.
Another factor to be considered is that most of our power comes from thermal sources which use an intermediate stage of pressurized steam to drive the generators. The dynamics of steam production is much slower than the load. That is, load can change from 0-max-0 instantly (imagine flicking a switch) but the steam pressure takes hours to go from 0-max-0, because it takes hours to burn the coal and produce heat and then put off the coal in case you don't require the heat. This slow dynamics of steam is the reason why the electric grid can never be 100% thermal or nuclear based. There has to be a fast dynamic power system like a battery-inverter or a hydro power supply.
A hydro power station can instantly turn on or off the water flow based on load and therefore acts as a savior of the thermal power generators.

With this said, if everyone turns off their lights suddenly, this will significantly reduce the load and the thermal power generators will suddenly experience an acceleration (imagine your car going downhill with no brakes!) which in turn will increase the frequency (it is proportional to speed) and cause the grid to trip. This can soon turn catastrophic because the steam pressure in the thermal plant boilers can shoot up quickly and may lead to explosions or worse! If not planned before hand, a simple act of half of the population turning off their lights for 9 minutes can completely kill the grid!
But thankfully, the engineers have got a 48 hour notice which is more than enough to plan for this event. The engineers can now schedule the amount of coal burn (or nuclear fuel) in such a way that during those 9 minutes, they only produce the energy demanded by the expected load. They may also use more of hydroelectric power during those 9 minutes to cater for unexpected variations in their predicted load.

A similar event occurs during commercial breaks of British sport events where everyone suddenly turns on their kettles to boil tea which puts a huge stress on the grid! This is explained in this wiki: https://en.m.wikipedia.org/wiki/TV_pickup

Why make such farfetched assumptions? India did not get electric grid yesterday and power generation and transmission activities are far more sophisticated than some human turning generation of power plants up or down by seeing how many lights are on in neighborhood. There is a highly remote possibility that electricity demand may dip during those 9 minutes (extremely rare chance though) but generator turbine load will automatically be reduced and then increased again when demand comes back. This will all happen without any human intervention and most likely will only be noticed by those sitting in power plant control rooms.

Grid is far more robust than this. Period.

I think you didn't read my post fully. Let me quote my own post for you:
Being an electrical engineer, I thought of explaining the functioning of the grid in simple terms and that's all I did. I did not make any assumptions nor was I saying that the grid is not robust. Sudden power demand fluctuations are a serious safety concern for any grid and if not planned and managed effectively, no grid in the world is robust enough.
If you read the wiki link that I had shared, you will notice that this effect has been well researched and documented.
Also, power engineers like to manage these load fluctuations proactively rather than reactively. Had the PM announced us to switch off all lights for the next 5 minutes out of the blue and if everyone followed, it will definitely be catastrophic! Even a 1.5Hz change in frequency (3% fluctuations in load) can cause the safety systems to kick in and start isolating the grid for safety.
Please read about the 2012 power blackouts in India and you will see that the cause of the blackout was a abnormal demand in electricity.
Again, please don't panic because the engineers got sufficient time to plan for this and take preventive measures.

This is unlike the TV Pickup issue where the engineers have to literally watch a TV serial or a Tennis match (which has no fixed time of end) in real time to predict consumer behavior and schedule the power stations accordingly!
I am not making this up. Please read the wiki.

And please read my posts from a technical point of view. If you have anything to refute, please provide references and we can have a healthy discussion. Thanks

Message from the Assistant Executive Engineer, Bescom to our apartment association. I'm sure this goes out to all BESCOM divisions in Bangalore.

IMHO, this was completely unnecessary and avoidable. Our PM should've stuck to clanging pots and pans.

The grid, power generating stations, sub stations are all connected with advanced monitoring relays and are networked.

Also, just powering off the lights should not cause any harm. There will still be enough load on the grid. Not sure how many will follow this. I certainly will not :)

I am not keen on getting drawn into futile discussions. Thank you.

Since you are an electrical engineer, you would know that generators are not allowed to go more than 0.5 Hz out of synchronization. 1.5 Hz out of sync is way past tolerance. Also, grid isolation compounds the problem when it is effected due to demand exceeding generation. If demand drop suddenly, steam to turbines can be easily bypassed to match the load. If in worst case generator falls out of sync and isolates due to falling frequency, reduction in power going into grid will bring frequency up.

Agreed. But the demand is going to less than generation in this case.

What will happen to the energy that was being produced by the steam turbines if they are suddenly isolated? Where will this energy go? Steam power plants sometimes need days to get up to speed after isolation. Please read about Base Load power plants if you are not familiar with the concept.

Again, the point of my original post was not to scare everyone about a power blackout. I was merely trying to point out the technical challenges and the numerous research which has been conducted regarding such events. Thanks to these studies, our engineers behind the scenes at SLDCs know what to do and have planned accordingly as this is a scheduled event. Any unplanned power fluctuation beyond the measures taken by the engineers can surely cause a blackout, even if it was temporarily. That is why you can see pleas from heads of electricity departments asking us not to switch off all appliances and only switch off lights.

Neither am I seeing any backing to your claims. Let's agree to disagree and move on.

I have no technical idea about the effect of switching lights off on the power grid. I'm assuming that the load will probably be similar to the day during these lockdown days with no industrial consumption to speak of in any case but we did get to see a circular that's been sent across to the concerned department and they're preparing for the light out already.

Attaching the same though i don't know about the authenticity of the same.

I am wondering in such dire times for this country, even if there is a 0.1% chance of the electrical grid of this country facing any damage, why do it for such nonsense theatrics and circus?

I don’t have much to add to the Electricity discussion as i am not a SME but thought of sharing this SMS which I just received from TorrentPower

Hello, I am concerned about home electronics due to drop in power demand during this time and resulting in frequency of power variation. I did some quick research. India's households are estimated at about 250M. If 100M of those turn off some lights, assume average 50W in reduction per household, this will result in a drop in demand of about 5GW. India's install capacity of power generation is about 370GW.
Any thoughts on this?
P. S. Couldn't find a thread on this topic, so request mods to merge if I am wrong.