Power grids require highly accurate, distributed clocks.
Well they don't strictly require them, but having that capability increases efficiency, robustness and safety.
They need to be accurate because electricity is fast - so a lot of protection schemes need to have a decision made across very long distances (which breaker, at which point on a 100 mile long transmission line should be fliped to isolate faults or stop "bad things" propagation) with minimal impact to the system as a whole.
They also need to be accurate because a good measure of frequency and phasor at geographically disparate points allows system tuning. A tiny change - e.g. speed up one of the 100s of generators could result in a much smoother, overall more-efficient transmission system. Similarly, adjustments to capacitor banks and transformers can provide slight phase adjustments for optimal power flow. But these resources are hundreds of miles apart - e.g the western half of the US and Canada (and parts of Mexico) (except for texas) is one big system.
Being a large, physical system, with feedback, and also being electricity, you get some very interesting effects to try and reason about. There can be very slow (relatively) oscillations in the system, but at the same time you have many, many high frequency noise signals mixed in to the elecrical signal. To find trends and patterns for the slow oscillations you need a very high sample rate to determine what noise to ignore. And these samples need to be time aligned, because even a perfect wave will have different phases at different points along it's propagation.
Anyway - that's an example I'm familiar with. I hope it made sense, seeing as I may not have had quite enough coffee yet.
Well they don't strictly require them, but having that capability increases efficiency, robustness and safety.
They need to be accurate because electricity is fast - so a lot of protection schemes need to have a decision made across very long distances (which breaker, at which point on a 100 mile long transmission line should be fliped to isolate faults or stop "bad things" propagation) with minimal impact to the system as a whole.
They also need to be accurate because a good measure of frequency and phasor at geographically disparate points allows system tuning. A tiny change - e.g. speed up one of the 100s of generators could result in a much smoother, overall more-efficient transmission system. Similarly, adjustments to capacitor banks and transformers can provide slight phase adjustments for optimal power flow. But these resources are hundreds of miles apart - e.g the western half of the US and Canada (and parts of Mexico) (except for texas) is one big system.
Being a large, physical system, with feedback, and also being electricity, you get some very interesting effects to try and reason about. There can be very slow (relatively) oscillations in the system, but at the same time you have many, many high frequency noise signals mixed in to the elecrical signal. To find trends and patterns for the slow oscillations you need a very high sample rate to determine what noise to ignore. And these samples need to be time aligned, because even a perfect wave will have different phases at different points along it's propagation.
Anyway - that's an example I'm familiar with. I hope it made sense, seeing as I may not have had quite enough coffee yet.