Why Does the U.S. Have Three Electrical Grids?
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Why Does the U.S. Have Three Electrical Grids?
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Re: Why Does the U.S. Have Three Electrical Grids?
#2Australia is comparable in size, split by a giant middle desert (literally and figuratively) And has two grids.
Balancing the east coast grid is sometimes hard. Its weak, badly in need of capital investment and somewhat mired in inter-state/federal madness.
Personally, I think privatizing the utility function was insane.
There are some cool things which emerged after the 1970s grounded capital investment: High Voltage DC is very cool. Avoids some of the issues of phase and load mis-alignment between regions, generation models.
Arguments for a different kind of net exist. More local resiliency. More load shedding, more respect for home solar and batteries, as well as storage in the network.
Re: Why Does the U.S. Have Three Electrical Grids?
#3The most interesting national electricity grid has to be Japan's, with two completely different networks operating at different frequencies, and connected by HVDC.
Re: Why Does the U.S. Have Three Electrical Grids?
#4> Everything within those separate zones is synched up. So you’ve got your 60 hertz AC wave; 60 times a second the AC power flow is changing direction. And all of the generators, all of the power consumption within each zone is doing that synchronously. But the east is doing it on its own. The West is on a different phase. Same for Texas.
Folks may not realize that power is transmitted in three phases in the US. AC power is essentially a sin wave, and we use 3 different 'phases', which are just shifted sin waves so that we basically always have at least one phase providing power at any time.
Every generator hooked up to the grid must be synchronized to the same 60 hz phases. There are devices called 'phasors' that assist in ensuring generators are lined up with the grid. And now there are networked versions to help coordinate across large regions.
But if two grids are on different phases, then there will be serious problems in connecting them together -- mostly that generators will be fighting against each other and potentially causing damage to things on the grid expecting clean 60hz power. It gets complicated pretty quickly.
Re: Why Does the U.S. Have Three Electrical Grids?
#5> Everything within those separate zones is synched up. So you’ve got your 60 hertz AC wave; 60 times a second the AC power flow is changing direction. And all of the generators, all of the power consumption within each zone is doing that synchronously. But the east is doing it on its own. The West is on a different phase. Same for Texas. Folks may not realize that power is transmitted in three phases in the US. AC p…
The solution is to connect them with HVDC, right? That might not be a great solution for making a single national-grid, but it would allow the 3 grids to mutually borrow from each other, right?
Re: Why Does the U.S. Have Three Electrical Grids?
#6> Everything within those separate zones is synched up. So you’ve got your 60 hertz AC wave; 60 times a second the AC power flow is changing direction. And all of the generators, all of the power consumption within each zone is doing that synchronously. But the east is doing it on its own. The West is on a different phase. Same for Texas. Folks may not realize that power is transmitted in three phases in the US. AC p…
>"[W]e basically always have at least one phase providing power at any time."
This isn't really how three-phase power works.
In household settings, you're usually getting only one phase, so all your power comes from that phase. Different neighborhoods get different phases, so they're roughly balanced loads.
Industrial (and some consumer) users get two (208V) or three phases (480V), and they get power from the difference between the phases (for their higher-voltage loads).
Now, if you've ever looked at an oven or a dryer (in North America at least), you'll know that they are higher voltage, and look like they are two-phase... But it's really more like one phase that's been mirrored.
Here's a nice diagram: https://electronics.stackexchange.com/questions/146420/obtai...
Re: Why Does the U.S. Have Three Electrical Grids?
#7> Everything within those separate zones is synched up. So you’ve got your 60 hertz AC wave; 60 times a second the AC power flow is changing direction. And all of the generators, all of the power consumption within each zone is doing that synchronously. But the east is doing it on its own. The West is on a different phase. Same for Texas. Folks may not realize that power is transmitted in three phases in the US. AC p…
"Folks may not realize that power is transmitted in three phases in the US"
My office in the UK has three phase power (I own it.) The phase shift thing is to enable putting more power into a place and nothing to do with "so that we basically always have at least one phase providing power at any time." whatever that means.
My home only has one phase because I don't need to draw that much power here (yet.)
Re: Why Does the U.S. Have Three Electrical Grids?
#8> Everything within those separate zones is synched up. So you’ve got your 60 hertz AC wave; 60 times a second the AC power flow is changing direction. And all of the generators, all of the power consumption within each zone is doing that synchronously. But the east is doing it on its own. The West is on a different phase. Same for Texas. Folks may not realize that power is transmitted in three phases in the US. AC p…
The speed of light is an issue as well - it takes about 1/60 of a second to cross the US.
This means it's impossible to synchronize the entire grid. The synchronization depends on the length of the path across the US.
I'm not sure actually how they propose to deal with this.
Edit, found this: https://news.ycombinator.com/item?id=16536121
Re: Why Does the U.S. Have Three Electrical Grids?
#9> Everything within those separate zones is synched up. So you’ve got your 60 hertz AC wave; 60 times a second the AC power flow is changing direction. And all of the generators, all of the power consumption within each zone is doing that synchronously. But the east is doing it on its own. The West is on a different phase. Same for Texas. Folks may not realize that power is transmitted in three phases in the US. AC p…
The solution is to connect them with HVDC, right? That might not be a great solution for making a single national-grid, but it would allow the 3 grids to mutually borrow from each other, right?
It's a lot of current, so maybe you want superconducting HVDC:
Re: Why Does the U.S. Have Three Electrical Grids?
#10> If you look at lists of the 100 greatest inventions of all time, electricity figures prominently. Once you get past some key enablers that can’t really be called inventions—fire, money, the wheel, calendars, the alphabet
Well that's a doozy of a way to start. How is electricity an invention but those listed after are not?