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Spain is about to face the challenge of a "black start"

arstechnica.com

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Re: Spain is about to face the challenge of a "black start"

#111

Post by tenthirtyam »

Bjartr wrote: post #106
tenthirtyam wrote: post #84

Earlier quoted context omitted.

I've always wondered why we can't just have a "master" power station transmit a 50Hz signal modulated at, say, 50MHz. Then all the other station simply sync to that, including small scale such as domestic PV etc. Then depending on how out-of-sync a given station is with the signal, they ramp production up or down accordingly. Is the problem here that there is inadequate or slow feedback to the supply side regarding l…

That's more or less how it works. Knowing what 50hz is and how out of sync a generator is is easy. AFAIK, the problem is one of inertia, both electrical and mechanical. A generator is a spinning mass, the more load on the generator, then the slower it turns. How fast it turns decides the frequency of power it generates. Say you get your generators running at 50hz at night, and then during the day it gets hot and thou…

Thanks for the reply. In the 50Mhz-modulated-50Hz scenario, however, the modulated 50Hz signal doesn't change under load; it has zero inertia (or infinite inertia maybe) because it's electronically generated.

Any individual station that gets out of sync either works hard to catch up, or gets disconnected.

The problem, as I see it, is that the load signal is equal and equivalent to the sync signal and maybe they could be separated. (e.g. the FM modulated signal wouldn't have to be a sine wave, nor would it even have to be 50Hz)

> what if two or more power stations see a low frequency grid and decide to ramp up more generators?

Seems to me it would solve this problem - they both have a single invariant sync signal.

> Connect a stopped, or sufficiently out of phase generator to a full scale power grid and the puny thousands of pounds of metal that make up a generator are going to get ripped apart

Seems to me this problem is solvable with electronics, but I don't know enough to say how much out-of-phase is problematic. What if, as you say, some heavy load is switched on, the local nuclear turbines slow by a fraction for a few 10s of seconds, and so a home PV array starts leading by 0.01Hz (e.g. home PV at 50.00Hz, local power station at 49.99Hz, so after 10s the PV is fully 36º or 0.6rad ahead). Does this result in the inverter (or the small local windfarm) exploding? Is that a realistic scenario?

> there needs to be more communication across the grid than just responding to the locally observed frequency

Precisely - a grid-wide sync signal, modulated at high frequency.

Re: Spain is about to face the challenge of a "black start"

#112

Post by tenthirtyam »

everyone wrote: post #81

What caused it? Nowadays when anything like this happens in the EU, I immediately wonder if it was Russian saboteurs. They have certainly been destroying infrastructure here, eg. undersea internet and power cables.

I was wondering if a solar flare could cause something like this. But if it had been that on this occasion, the astronomers would've been warning about it for at least 8 minutes. :-)

Re: Spain is about to face the challenge of a "black start"

#113

Post by [deleted] »

m4rtink wrote: post #103
ffsm8 wrote: post #65

Earlier quoted context omitted.

It's even worse in satisfactory imo, because the game is build around your fabs consuming wildly varying amounts of power throughout their production cycle... And after a power loss, they'll not only need the initial burst (can be handled via batteries) but will also now all be synchronized to have their power spikes at exactly the same moment. Dyson sphere program is the by far most forgiving in that regard. You can…

Also in Satisfactory pumps need power to run, so coal power plants quite realistically won't start without extra power (unless you have a water tower on the input).

[deleted]

Re: Spain is about to face the challenge of a "black start"

#114

Post by rdtsc »

pjc50 wrote: post #78
rdtsc wrote: post #67

Earlier quoted context omitted.

Just like there is vibe coding, this is vibe downvoting: “they are probably right, but kinda feels like they are dissing renewables, and I like renewables, better downvote just in case”

You're right, but: the renewables "debate" is a massive tar-pit of bad faith arguments. People are tired of rehashing that. The best solution is not to slow the rollout of renewables but to accelerate the rollout of battery storage. (also we're a bit early for a proper postmortem, but that's an inevitable reality of social media, got to get the talking points in before the facts)

> The best solution is not to slow the rollout of renewables but to accelerate the rollout of battery storage.

I agree as well. And I think the gp (or the ggp?) post noticed that there is a lack of "spinning mass" to do frequency damping would have agreed as well. They could be merely suggesting to add just spinning mass synchronizers. These could be independent units, doing just that or maybe even convert some old power plants: "just" decouple the turbine from the generator.

Re: Spain is about to face the challenge of a "black start"

#115

Post by Tade0 »

justlikereddit wrote: post #94
Tade0 wrote: post #86

Earlier quoted context omitted.

Again, this appears to be a problem of coordination. An inverter doesn't have to: -react immediately -use its full capacity all the time

You have a fundamental misunderstanding of both how a grid in blackout mode appears to a lonely inverter and what means of coordinating inverters that are available to said inverter. Imagine you're trying to coordinate a choir of ten million singers that are scattered across a radius of a thousand kilometer, that all sing into their individual Ham radio. And you need it to come out in a perfect unison that sounds goo…

Thing is, it's not ten million - it's several orders of magnitude fewer, particularly if we're starting with just a selected list of generators.

Also we know the locations of the generators, so we can calculate the phase shift and control them accordingly. At thousand kilometres it's around 60 degrees anyway, so not catastrophically huge.

Re: Spain is about to face the challenge of a "black start"

#116

Post by justlikereddit »

mystified5016 wrote: post #108
justlikereddit wrote: post #94

Earlier quoted context omitted.

You have a fundamental misunderstanding of both how a grid in blackout mode appears to a lonely inverter and what means of coordinating inverters that are available to said inverter. Imagine you're trying to coordinate a choir of ten million singers that are scattered across a radius of a thousand kilometer, that all sing into their individual Ham radio. And you need it to come out in a perfect unison that sounds goo…

Man, if only we had some means of instantaneous communication at a distance. What a crazy world that would be, huh?

Superluminal information transfer would be more useful for other areas than grid synchronization, but yeah we don't have crazy tech like that. And if we attempt to synch to a 50hz frequency over the internet means a 10ms latency difference results in 180 degree out of phase input.

And even if we did have the superluminal grid sync signal the propagation of electricity itself is slower than C and you'll need to consider perceived phase synchronization over distance.

Re: Spain is about to face the challenge of a "black start"

#117

Post by moralestapia »

moralestapia wrote: post #60
lifty wrote: post #57

Earlier quoted context omitted.

Not sure why you are downvoted but this rings true to me.

For about 2-3 years the default for people here has been to downvote everything rather than driving discussion; much more reddit-esque than what it used to be. There are no other sites like this one to jump to, unfortunately. On-topic: Wind power brings in about 20% of Spain's electricity, and that one fluctuates a lot indeed. I hope they put out a detailed post-mortem, I'd be an enjoyable read.

Exhibit A: this comment.

Some even borrowed the essence of it, posted it elsewhere and still downvoted, ¯\_(ツ)_/¯.

Re: Spain is about to face the challenge of a "black start"

#118

Post by abe_m »

khafra wrote: post #80
abe_m wrote: post #75

Earlier quoted context omitted.

At the time I'm writing this, there appears to be about equal (hydro + gas) = (solar + wind). It appears they are running a significant portion of the grid with high inertia generators. In a control system when you have an actuator that is much more responsive than the load, you can get into instable operating regimes where. On a small scale, when you are setting up servo motors, there is an inertia matching ratio fo…

Seems like a simple cybernetics problem, especially if it's point-to-point. If there's many different inverters on the same circuit, you might need something like a directed graph, but there should be simpler, more local solutions.

I'm sure the inverter manufacturers are working on something.

At the start of solar and wind integration, it didn't matter. Large rotating generators were the main source on the grid, and provided stability. We're in a different world with an all-inverter grid control perspective-wise.

I think there is also still an information issue. The grid is definitely not point-to-point. It also isn't all generators. You also have loads switching on and off at indeterminate times. There is an overall predictability to it, but not at the phase governing resolution. If you have a local inverter and the phase slows down, you don't know if it is a remote inverter that has over-slowed, to which you shouldn't respond as it will fix itself, or a near-by load that suddenly switched on, to which you should respond as demand is now greater, and needs more supply. With big rotating generators, it doesn't really matter, as they are time averaging with the large inertia to stabilize the load/generator balance.

Re: Spain is about to face the challenge of a "black start"

#119

Post by abe_m »

Tade0 wrote: post #115
justlikereddit wrote: post #94

Earlier quoted context omitted.

You have a fundamental misunderstanding of both how a grid in blackout mode appears to a lonely inverter and what means of coordinating inverters that are available to said inverter. Imagine you're trying to coordinate a choir of ten million singers that are scattered across a radius of a thousand kilometer, that all sing into their individual Ham radio. And you need it to come out in a perfect unison that sounds goo…

Thing is, it's not ten million - it's several orders of magnitude fewer, particularly if we're starting with just a selected list of generators. Also we know the locations of the generators, so we can calculate the phase shift and control them accordingly. At thousand kilometres it's around 60 degrees anyway, so not catastrophically huge.

But also, it isn't just generators, it is also the indeterminate loads. If you have nearby loads switching on and off that are similar sized to your local inverters, that is a complicated controls modelling problem.

I'm pretty sure in grid terms, 60 degrees out of sync is catastrophic. I'm pretty sure you'll be disconnected by protection circuits before it gets that far out.

Re: Spain is about to face the challenge of a "black start"

#120

Post by justlikereddit »

tenthirtyam wrote: post #111
Bjartr wrote: post #106

Earlier quoted context omitted.

That's more or less how it works. Knowing what 50hz is and how out of sync a generator is is easy. AFAIK, the problem is one of inertia, both electrical and mechanical. A generator is a spinning mass, the more load on the generator, then the slower it turns. How fast it turns decides the frequency of power it generates. Say you get your generators running at 50hz at night, and then during the day it gets hot and thou…

Thanks for the reply. In the 50Mhz-modulated-50Hz scenario, however, the modulated 50Hz signal doesn't change under load; it has zero inertia (or infinite inertia maybe) because it's electronically generated. Any individual station that gets out of sync either works hard to catch up, or gets disconnected. The problem, as I see it, is that the load signal is equal and equivalent to the sync signal and maybe they could…

You need to consider that a master clock signal transmitted through air will arrive at a different time than an AC power wave transmitted through a wire.

A millisecond latency will cause a significant out of phase shift to the AC signal too.

The AC data you want is already codified in the power signal

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