5 ms·

You know your power will be cut, and you know it will be a certain amount of time, and you know roughly where you are in the schedule. Knowing when the power w

by Bender 1y ago

You know your power will be cut, and you know it will be a certain amount of time, and you know roughly where you are in the schedule. Knowing when the power will be cut will not help unless I am misunderstanding you. If the data-center loses power for even a minute the generators will all fire up and then every ATS will count-down and transfer in 30 seconds. Battery backup only lasts just long enough to do a quick return to service on a failed generator and even that is sketchy at best. A properly engineered data-center can run on reduced generator capacity. Some data-centers are indeed on circuits deemed to be critical but I could see regulations changing this so that they are "business critical" vs. "life support critical" and some changes could be made at substations so that data-centers could participate in shedding. I think you are right that they will be thinking about this and adding to this probably filing preemptive lawsuits to protect their business. Such changes can violate SLA contracts businesses have with power companies and Texas is very pro-business so I can not compare it to California.

toast0 1y ago
> Knowing when the power will be cut will not help unless I am misunderstanding you. If the data-center loses power for even a minute the generators will all fire up and then every ATS will count-down and transfer in 30 seconds. Battery backup only lasts just long enough to do a quick return to service on a failed generator and even that is sketchy at best. A properly engineered data-center can run on reduced generator capacity. If you know when the power will be cut, you can start the generators before the cut, and depending on your equipment, you may be able to synchronize the generator(s) with the grid and switch over without hitting the batteries. I assume big datacenters are on three phase, can you switch over each phase as it crosses zero, or do you need to do them all at once?
- Bender 1y ago
  At least in the data-centers I helped manage the inverters were in-line running 100% duty-cycle, meaning frequency sync is not required as there is no bypass. The servers never see the raw commercial power. Data-centers in the US are indeed 3-phase. FWIW the big Cats did have controllers that would maintain sync even when commercial power was gone but we did not need it. There wasn't even a way to physically merge commercial and generator power. ATS inputs and outputs were a binary choice. I know what you mean though, the generators I worked with in the military had a manual frequency sync that required slowly turning a dial and watching light bulbs that got brighter with frequency offset. Very old equipment for Mystic Star, post-WWII era equipment. 50's to 90's
  - jimmygrapes 1y ago
    Manually syncing several of the MEP012 generators was always far more stressful to me than any physical dangers!
    - Bender 1y ago
      I bet. I never messed with the trailer or skid mounted generators. It sounds like you were also USAF. At least modern day noise cancelling headphones are much better. Guessing you probably have tinnitus from working on them. At least I think that is partially where mine came from.
  - dylan604 1y ago
    In the facilities I have been in (not managed), they were all in-line as you describe as well. Mains power is dirty. Having a data center without line condition on mains would be insane.
    - Bender 1y ago
      Mains power is dirty. Having a data center without line condition on mains would be insane. Agreed. Even my home computer and networking equipment is 100% in-line with inverters and never see commercial power. PG&E in California got me into this habit with all the Planned Safety Power Shutoffs, wildfires, surges from really old transformers and unplanned outages. Now each of my tiny indoor rings of power have 200 to 800 amp-hour capacity each and over-sized inverters. I put the whole-house inverter plans on hold for now.
      - dylan604 1y ago
        way back when, I worked for a VHS dubbing facility where we had a voltage meter with an alarm set to warn when voltage would drop below a certain rate, but I don't remember the exact value. At that point, the VCRs would glitch and the recordings would be bad but the dip would be momentary and not enough to force the machines to stop like a full outage. When the alarm sounded, we stop all of the decks and re-rack the room and restart all of them. Without the alarm, it was impossible to catch these without 100% QC of a tape. That is when I groked how much worse a dip can be than a spike. Some equipment will start to pull harder when the voltage drops which kills more power supplies than spikes. Surge protectors are great for the spikes, but line conditioners or battery backups are the only protection from the dips. Management decided that the fully time battery conditioned expense was not worth it, so we were constantly running with some set of equipment down because of a dead power supply
- bluGill 1y ago
  Again, that doesn't matter because everyone knows the grid isn't 99% reliable. They just pull the big power switch to the whole building and watch all the backup systems work. If anything fails it was broke already and they fix/replace it. Because this happens often they have confidence that most systems will work - even where it doesn't computers fail unexpectedly anyway and so they have redundancy of computers anyway (and if it is really important redundancy of a data center in a different state/country) Synchronizing generators is a thing, but it isn't useful for this situation since they need to be able to handle the sudden without warning power loss where generators cannot be synchronized anyway.
  - stevetron 1y ago
    How often does that inverter burn-out a transistor? Is there a backup inverter? Do you keep replacement transistors on-site?
    - Bender 1y ago
      Commercial inverters are massive and highly redundant. They do fail but it is very rare and there are contractors that can be on site to fix things very quickly. A properly engineered system can run in a degraded state for a prolonged period of time.
    - hdgvhicv 1y ago
      My data centres have two separate supplies through two separte ups with two seperate generators, kit is striped across each one. Of course that doesn’t help for fire/flood etc which is why we have critical workloads in two dcs.
      - bluGill 1y ago
        I once worked in a building that had two separate connections to the grid which went to different substations. Their servers have more than one power supply as well so that either grid could go down. While somewhat of an outlier, it is an option if you care about this.
imglorp 1y ago
Texas has shown no interest in life support critical. They prioritized operator profits over uptime. Hundreds died as a result. https://en.wikipedia.org/wiki/2021_Texas_power_crisis https://en.wikipedia.org/wiki/2021_Texas_power_crisis
- doodlebugging 1y ago
  >Texas has shown no interest in life support critical. I'm not sure that this is correct. I was initially worried about how Mom would fare since she lives alone and is over 80. During the entire one week period of power problems in Feb. 2021 my Mom never lost power, not even a quick brown-out. Her home is within a half mile of a local hospital which also never lost power. The area around the hospital did not lose power so businesses and homes close by had no issues with heating, cooking, bathing, etc during the cold blast. That fact allowed me to stay here at my place a couple hours away and manage my own situation which was fairly easy compared to many others in the state. Your other statements are quite true and to date no one who played a part in mismanagement of utility power in Texas has been held accountable nor will they ever be in a libertarian state where regulations exist only to guarantee a profitable situation for a commercial entity. In fact, most electricity customers in Texas ended up paying for the huge cost increases that occurred as those in charge tweaked the system in real time to maximize their own profits. Texas needs regulations worse than most other states. Grifters, fraudsters, and thieves have filled too many critical positions for too long.
  - grepfru_it 1y ago
    Heating your house/cooking/bathing etc during this time put extraordinary strain on the grid. A big reason why others did not have power is because those that did did not reduce their consumption by much. So many of my neighbors/friends/collegues made comments like "we didn't lose power, so we kept the heat cranking at 75". So it would make sense that load shedding primarily affected neighborhoods, but my recollection of the events from people who lived near emergency centers was use it up before it goes away.
    - doodlebugging 1y ago

by Bender 1y ago

toast0 1y ago

> Knowing when the power will be cut will not help unless I am misunderstanding you. If the data-center loses power for even a minute the generators will all fire up and then every ATS will count-down and transfer in 30 seconds. Battery backup only lasts just long enough to do a quick return to service on a failed generator and even that is sketchy at best. A properly engineered data-center can run on reduced generator capacity. If you know when the power will be cut, you can start the generators before the cut, and depending on your equipment, you may be able to synchronize the generator(s) with the grid and switch over without hitting the batteries. I assume big datacenters are on three phase, can you switch over each phase as it crosses zero, or do you need to do them all at once?

Bender 1y ago
At least in the data-centers I helped manage the inverters were in-line running 100% duty-cycle, meaning frequency sync is not required as there is no bypass. The servers never see the raw commercial power. Data-centers in the US are indeed 3-phase. FWIW the big Cats did have controllers that would maintain sync even when commercial power was gone but we did not need it. There wasn't even a way to physically merge commercial and generator power. ATS inputs and outputs were a binary choice. I know what you mean though, the generators I worked with in the military had a manual frequency sync that required slowly turning a dial and watching light bulbs that got brighter with frequency offset. Very old equipment for Mystic Star, post-WWII era equipment. 50's to 90's
- jimmygrapes 1y ago
  Manually syncing several of the MEP012 generators was always far more stressful to me than any physical dangers!
  - Bender 1y ago
    I bet. I never messed with the trailer or skid mounted generators. It sounds like you were also USAF. At least modern day noise cancelling headphones are much better. Guessing you probably have tinnitus from working on them. At least I think that is partially where mine came from.
- dylan604 1y ago
  In the facilities I have been in (not managed), they were all in-line as you describe as well. Mains power is dirty. Having a data center without line condition on mains would be insane.
  - Bender 1y ago
    Mains power is dirty. Having a data center without line condition on mains would be insane. Agreed. Even my home computer and networking equipment is 100% in-line with inverters and never see commercial power. PG&E in California got me into this habit with all the Planned Safety Power Shutoffs, wildfires, surges from really old transformers and unplanned outages. Now each of my tiny indoor rings of power have 200 to 800 amp-hour capacity each and over-sized inverters. I put the whole-house inverter plans on hold for now.
    - dylan604 1y ago
      way back when, I worked for a VHS dubbing facility where we had a voltage meter with an alarm set to warn when voltage would drop below a certain rate, but I don't remember the exact value. At that point, the VCRs would glitch and the recordings would be bad but the dip would be momentary and not enough to force the machines to stop like a full outage. When the alarm sounded, we stop all of the decks and re-rack the room and restart all of them. Without the alarm, it was impossible to catch these without 100% QC of a tape. That is when I groked how much worse a dip can be than a spike. Some equipment will start to pull harder when the voltage drops which kills more power supplies than spikes. Surge protectors are great for the spikes, but line conditioners or battery backups are the only protection from the dips. Management decided that the fully time battery conditioned expense was not worth it, so we were constantly running with some set of equipment down because of a dead power supply
bluGill 1y ago
Again, that doesn't matter because everyone knows the grid isn't 99% reliable. They just pull the big power switch to the whole building and watch all the backup systems work. If anything fails it was broke already and they fix/replace it. Because this happens often they have confidence that most systems will work - even where it doesn't computers fail unexpectedly anyway and so they have redundancy of computers anyway (and if it is really important redundancy of a data center in a different state/country) Synchronizing generators is a thing, but it isn't useful for this situation since they need to be able to handle the sudden without warning power loss where generators cannot be synchronized anyway.
- stevetron 1y ago
  How often does that inverter burn-out a transistor? Is there a backup inverter? Do you keep replacement transistors on-site?
  - Bender 1y ago
    Commercial inverters are massive and highly redundant. They do fail but it is very rare and there are contractors that can be on site to fix things very quickly. A properly engineered system can run in a degraded state for a prolonged period of time.
  - hdgvhicv 1y ago
    My data centres have two separate supplies through two separte ups with two seperate generators, kit is striped across each one. Of course that doesn’t help for fire/flood etc which is why we have critical workloads in two dcs.
    - bluGill 1y ago
      I once worked in a building that had two separate connections to the grid which went to different substations. Their servers have more than one power supply as well so that either grid could go down. While somewhat of an outlier, it is an option if you care about this.

imglorp 1y ago

Texas has shown no interest in life support critical. They prioritized operator profits over uptime. Hundreds died as a result. https://en.wikipedia.org/wiki/2021_Texas_power_crisis https://en.wikipedia.org/wiki/2021_Texas_power_crisis

doodlebugging 1y ago
>Texas has shown no interest in life support critical. I'm not sure that this is correct. I was initially worried about how Mom would fare since she lives alone and is over 80. During the entire one week period of power problems in Feb. 2021 my Mom never lost power, not even a quick brown-out. Her home is within a half mile of a local hospital which also never lost power. The area around the hospital did not lose power so businesses and homes close by had no issues with heating, cooking, bathing, etc during the cold blast. That fact allowed me to stay here at my place a couple hours away and manage my own situation which was fairly easy compared to many others in the state. Your other statements are quite true and to date no one who played a part in mismanagement of utility power in Texas has been held accountable nor will they ever be in a libertarian state where regulations exist only to guarantee a profitable situation for a commercial entity. In fact, most electricity customers in Texas ended up paying for the huge cost increases that occurred as those in charge tweaked the system in real time to maximize their own profits. Texas needs regulations worse than most other states. Grifters, fraudsters, and thieves have filled too many critical positions for too long.
- grepfru_it 1y ago
  Heating your house/cooking/bathing etc during this time put extraordinary strain on the grid. A big reason why others did not have power is because those that did did not reduce their consumption by much. So many of my neighbors/friends/collegues made comments like "we didn't lose power, so we kept the heat cranking at 75". So it would make sense that load shedding primarily affected neighborhoods, but my recollection of the events from people who lived near emergency centers was use it up before it goes away.
  - doodlebugging 1y ago