Comment by gblargg

7 hours ago

The ELI5 version is you're arm-wrestling someone and they suddenly let their arm go limp, so your arm slams down on the table since you can't react that fast.

3 comments

gblargg

Reply
flopbob  6 hours ago

To build on this analogy, tug of war fits a bit better. Nothing dramatic happens if one person let go, but if half of one team just let loose at the same time without communication, bad things happen.

  • cogman10  33 minutes ago

    I think an even better example is what happened to the Tacoma Bridge. You have an oscillating frequency and phase that needs to be precisely tuned in order for everything to work well. If something is out of sync wrong, you can end up with higher peaks, lower valleys, or flatter locations which can ultimately cause catastrophic failure.

    In the Tacoma example, the input frequency continued to add onto the bridges motion which ultimately caused it to destroy itself. In an electric grid, a misaligned phase can cause excessive spikes (imagine 480V when you expect 240V) or the generators to ultimately burn themselves out because 2 generators are fighting with each other, one trying to raise the voltage while another is trying to decrease the voltage. The really tricky thing is that load (particularly inductive or capacitive loads) look almost exactly like an unaligned generator.

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