601–610 of 1001 posts
Earlier quoted context omitted.
Did he mention the UK's plan in case they have a full blackout?
https://www.nationalgrid.com/sites/default/files/documents/H... (2017, probably current)
That sounds like someone explaining why the solution is so bad, before describing what the solution is.
This sounds big enough to require a black start. Unfortunately, those are slow and difficult. If an entire nation trips offline then every generator station disconnects itself from the grid and the grid itself snaps apart into islands. To bring it back you have to disconnect consumer loads and then re-energize a small set of plants that have dedicated black start capability. Thermal plants require energy to start up…
- Cause of event not known yet.
- They noticed power oscillations from the Spanish grid that tripped safety mechanisms in the Portuguese grid. At the time, due to the cheaper prices, the Portuguese grid was in a state of importing electricity from Spain.
- They are bringing up multiple power systems and the Portuguese grid is able to supply 100% of needs if required. It was not configured in such a state at the moment of event.
- They had to restart the black start more than once, since while starting, noticed instabilities in some sectors that forced them to restart the process.
- Time for full recovery unknown at this time, but it will take at least 24 hours.
This sounds big enough to require a black start. Unfortunately, those are slow and difficult. If an entire nation trips offline then every generator station disconnects itself from the grid and the grid itself snaps apart into islands. To bring it back you have to disconnect consumer loads and then re-energize a small set of plants that have dedicated black start capability. Thermal plants require energy to start up…
Does solar power make this process easier or harder? I know that with thermal plants you have a spinning mass that you have to synchronize, and phase shift is used to assess how hard the plant is working (and whether to trip a disconnect as we see here) But with solar, how is the synchronization provided? In like a giant buck? Or in software somehow? Does the phase shift matter as much as in the electromechanical sys…
If you mean how does solar detect phase and synchronize to the grid: https://en.wikipedia.org/wiki/Phase-locked_loop
If you mean how does solar act to reinforce the grid: search for terms like "grid forming inverter vs. grid following inverter" though not all generators are the same in terms of how much resilience they add to the grid, esp. w.r.t. the inertia they do or do not add. See e.g. https://www.greentechmedia.com/squared/dispatches-from-the-g...
Earlier quoted context omitted.
Report on a smaller event in the UK: https://www.ofgem.gov.uk/publications/investigation-9-august... (see linked pdf) That started from a combination of a lightning strike and generator trip, but turned into a local cascade failure as lots of distributed generation noticed that the frequency was under 49Hz and disconnected itself. I suspect the Spanish situation will be similar - inability to properly contain a frequ…
Is 50Hz really that important these days – i.e. more important than maintaining power? (Honest naive question.)
Its like a three legged race. You and your partner have to run in synchronism. If either of you slows down or speeds up, the other can trip and fall over taking both of you out.
Earlier quoted context omitted.
> I'm not sure pushing this down to the individual house is sensible. why not? Having distributed buffers ought to make the system more resilient in most cases wont it? Not to mention that these home level batteries can be used to smooth out power usage and lower peak loads. In fact, having an EV car act as this same battery would be an even more efficient use of resources.
The peak load of a house is substantially higher than the per-house peak load of a city. People don't all turn on their ovens/dryers/hairdriers at the same time. You could distribute this capacity at each house and feed it back to the grid during peak times. But is TCO of 1000 * 100kWh same price as 100MWh worth of capacity? If you're going to have the battery anyway(a car) its hard to compete with, but once you need…
I’ve set this up on my “smart” thermostat to speed up just before rates go up and kick off for a while once they do (and it was a pain to setup, somehow this functionality was not baked in)
This sounds big enough to require a black start. Unfortunately, those are slow and difficult. If an entire nation trips offline then every generator station disconnects itself from the grid and the grid itself snaps apart into islands. To bring it back you have to disconnect consumer loads and then re-energize a small set of plants that have dedicated black start capability. Thermal plants require energy to start up…
Earlier quoted context omitted.
I can appreciate the ability to revert to hand cranking an air compressor, yet I can't help but feel that the 99.99% of events, you'd be better served with keeping a two stroke gas engine ready to go. Air compressors tend to have parts just as or more vulnerable to environmental factors, and you get a lot more power for less elbow grease out of a two stroke.
A power station can start a decently large generator with batteries. Maybe there are other concerns for an oil rig.
The hand-pumped air compressor is the tool of last resort. You can try an engine start if there's someone there who's able to pump it. You don't have to worry about how much charge is left in your batteries or whether or not the gasoline for the 2-stroke pump engine has gone stale. It's the tool that you use as an alternative to "well, the batteries are dead too, guess we're not going to start the engine tonight... let's call the helicopters and abandon ship"
Earlier quoted context omitted.
In another life I worked as an engineer commissioning oil rigs and I’ve seen how tricky even a small-scale black start can be. On a rig, we simulate total power loss and have to hand-crank a tiny air compressor just to start a small emergency generator, which then powers the compressors needed to fire up the big ~7MW main generators. It's a delicate chain reaction — and that's just for one isolated platform. A full g…
I can appreciate the ability to revert to hand cranking an air compressor, yet I can't help but feel that the 99.99% of events, you'd be better served with keeping a two stroke gas engine ready to go. Air compressors tend to have parts just as or more vulnerable to environmental factors, and you get a lot more power for less elbow grease out of a two stroke.
Earlier quoted context omitted.
Not being at all qualified to comment (though I work for a power company), I'd think the hand crank air compressor wouldn't suffer from no spark or bad gas.
Stale gas was my guess for the plan. Maintaining an emergency system is one of those things that is easy to neglect.
Having good, fresh fuel on an oil rig. They need an engine that can run on crude.
This sounds big enough to require a black start. Unfortunately, those are slow and difficult. If an entire nation trips offline then every generator station disconnects itself from the grid and the grid itself snaps apart into islands. To bring it back you have to disconnect consumer loads and then re-energize a small set of plants that have dedicated black start capability. Thermal plants require energy to start up…
In another life I worked as an engineer commissioning oil rigs and I’ve seen how tricky even a small-scale black start can be. On a rig, we simulate total power loss and have to hand-crank a tiny air compressor just to start a small emergency generator, which then powers the compressors needed to fire up the big ~7MW main generators. It's a delicate chain reaction — and that's just for one isolated platform. A full g…
The words "it's a miracle it works at all" routinely popped up in those conversations, which is... something you don't want to hear about any sort of power generation - especially not nuclear - but it's true. It's a system basically built to produce "common accidents". It's amazing that it doesn't on a regular basis.