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xattt

Related, but this is a video about first sync of a refurbished unit at Bruce Nuclear Generating Facility.

https://m.youtube.com/watch?v=Zw39gxIqfVU

It’s still interesting that despite all that tech, there needs to be a person watching the sync clock.

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The synchroscope is a very important gauge for any power plant:

https://en.wikipedia.org/wiki/Synchroscope

In short, every generator is also an electric motor. When you connect a generator/motor to the grid, it begins rotating in sync with every other generator/motor on the grid. The grid will supply any amount of power required to speed up or slow down as needed, to keep everything locked together.

The initial synchronization process may be quite violent, depending on the size of the initial discrepancy.

The synchroscope is the gauge that shows the phase and frequency difference between the generator and the grid. Before closing the switch, operators align everything as closely as possible to ensure a smooth transition.

We have some older AC-AC converters to convert 60Hz wall power to 400Hz aircraft power 3 phase. They use a motor coupled to a generator, about 100kW output. If we shut one off and then restart it before it's fully spun down the phase difference between the motor and the grid is enough to make this thing kick and jump a fair bit. I'd love to see what happens at 200+MW! From a distance of course. I imagine the structural damage would be rather spectacular.

Strongly suspect some engineer included a 'weak' conductor somewhere as a sacrificial fuse. Wires tend to be way easier to replace than entire buildings. Just look at how violent aircraft jet engines are when they pop.

At those power levels, a 'fuse' can still pass a hell of a lot of energy before it burns itself out.

Obligatory link to the "Guide to fuse replacement" listing a wrench as a "2000 amp slow blow" fuse.

https://studyelectrical.com/wp-content/uploads/2020/06/Guide...

Someone tested such a thing on a pretty big generator: https://www.youtube.com/watch?v=LM8kLaJ2NDU

https://www.wired.com/story/how-30-lines-of-code-blew-up-27-...

> Black chunks began to fly out of an access panel on the generator, which the researchers had left open to watch its internals. Inside, the black rubber grommet that linked the two halves of the generator’s shaft was tearing itself apart.

This was a proof-of-concept for a cyber attack on power infrastructure.

They sent it malware that inverted the grid sync behavior from "Sync up, then connect, and if you de-sync, disconnect" to "If you are synced, disconnect, if you are desynced, reconnect"

The Wired article is an advert for a book filled with pretty fluffy prose - At times reading like a romance novel...

I’ve heard stories from my navy days, such as when they accidentally synchronized to the grid 180 out of sync (the automatic sync failed, this one wasn’t manual) and the two diesel generators ripped themselves from the hull and threw themselves across the space and destroyed several other things on the way. That was on an older ship and they decided not to repair it, so it was decommissioned.

here's a demo of it at a human understandable scale

https://www.youtube.com/watch?v=sFohkp2aaU4

In modern plants synchscopes are not common or nessessary. Auto synchronizers can routinely close machines into the grid with better accuracy and repeatability than human operators.

Watching this, a couple of questions came up in my mjnd:

1. Siemens rep physically touching things despite vibration sensors being in place - do they not trust the sensors? If they do not, how are they doing routine monitoring? Have someone sit atop the machine and feel for things 24/7? Or is that just the rep grandstanding for the cameras?

2. Time of grid sync only having hh:mm precision. Nitpick, but at 60hz, that is about 50s of imprecision.

3. The mentioned previous unsuccessful attempts - so went wrong? Dunno, I tend to learn more about systems from failure :)

It costs nothing to check. Gauges are one thing, but physical senses are good for intuition. It's no different from a racecar driver knowing their engine is underperforming because it sounds different.

> Siemens rep physically touching things despite vibration sensors being in place - do they not trust the sensors?

Trust but verify?

The building I currently work in used to have clocks that were synchronized by the power grid. The power company would guarantee a number of cycles per day. While the precision isn't always there your clocks would never be permanently drifted and that was good enough.

I haven't looked into it but the guy who sold me our current gps time receiver told me that power companies no longer offer a cycle guarantee.

A friend of mine lived in a deliberate-built uranium mining town about 30 km away from the Trans-Canada Highway. One day, it disconnected from the main grid for one reason or another, but still had power from a local hydroelectric dam.

The dam ran too slow, and everyone who relied on wired clocks ended up being 15 minutes behind in their day.

Thirty years ago I had a graduate assistantship in the physical plant of my university. One of the cool things I saw was a 55-gallon drum sized motor spin up to synchronize all the clocks on campus at noon.

In the European grid, grid time is tracked and adjusted as needed by nudging target frequency.

https://www.swissgrid.ch/en/home/operation/grid-data/current...

If it's the first time the equipment has spun up after the sensors were installed, maybe he's just validating the installation. Maybe they wouldn't be doing that 24/7, just every month or year, the same way I don't validate unit tests constantly, only when I write them and then occasionally after.

> Siemens rep physically touching things despite vibration sensors being in place

If the rep’s touch is calibrated, then it would perturb the sensors by a known amount and should validate the sensors are not resulting a metric that is permanently wrong.

> Siemens rep physically touching things despite vibration sensors being in place - do they not trust the sensors? If they do not, how are they doing routine monitoring? Have someone sit atop the machine and feel for things 24/7? Or is that just the rep grandstanding for the cameras?

You ever give a pair of kitchen tongs a few good clacks before using them? You know, just to make sure they're still clacking?

Similar, but a really small hydro plant: https://www.youtube.com/watch?v=xGQxSJmadm0

I was inside Bruce A when it was completely mothballed. Crazy that’s it’s back online

I was inside a Niagara hydro electric station in the 80s, they still had analog clocks on the wall for grid and station

Eventually with enough renewables on the grid, sync gets a little tougher, so far so good :)

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