There has been a lot of VFD discussion on the forum. I haven't used one in years as I no longer have any 3 phase machines. However, one of your posts the other day got me thinking about a topic I always took for granted but never researched: how do they phase-sync different power stations (i.e., big generators) on the electrical grid? The brown outs in Texas yesterday and the issues they are having with their grid due to snow (yes, snow and alligators in the same state) were a big topic of discussion on the snowblower forum I hang out on as well. While driving back from Metal SuperMarkets in Calgary today and watching the steam plumes along Stoney Trail from the Enmax generating station, I got thinking about this topic more and more.
Inverter type gas generators like my Honda EU2000 have sync modes on them now where you can connect a cable and the electronics do this automatically. (Mine is actually the older version that can't be sync'd, but you get the point.) But how do you do this, and how was it done in the old days before sophisticated electronics? Those of you old enough to remember the 1998 Quebec ice storms know that a big part of recovery was bringing the grid back online. The Quebec grid was more isolated from other grids at the time, so tapping into alternative grids was problematic. And for you real old timers like myself, you may recall the New York City Blackout that paralysed the Big Apple in 1977. Phase shift there severely complicated bringing the power back, and when they didn't get it right—it caused even more damage. Damage can be really expensive too; in New York they had subterranean transmission lines (which aren't preferred due to heat dissipation issues). So a screw-up here means somebody's getting called into a supervisor's office for a chat.
Until this problem was solved—and long after Tesla's AC based grids became the standard—there was no redundancy or ability to connect and leverage other grids. Whenever I look at those satellite maps of the abandoned Love Canal in New York State, I think how far we have come with our electrical grids.
Here's a great video that explains and illustrates the problem and how you solve it in a way that the average guy can understand. There are even cooler demos in the latter parts of the series.
Inverter type gas generators like my Honda EU2000 have sync modes on them now where you can connect a cable and the electronics do this automatically. (Mine is actually the older version that can't be sync'd, but you get the point.) But how do you do this, and how was it done in the old days before sophisticated electronics? Those of you old enough to remember the 1998 Quebec ice storms know that a big part of recovery was bringing the grid back online. The Quebec grid was more isolated from other grids at the time, so tapping into alternative grids was problematic. And for you real old timers like myself, you may recall the New York City Blackout that paralysed the Big Apple in 1977. Phase shift there severely complicated bringing the power back, and when they didn't get it right—it caused even more damage. Damage can be really expensive too; in New York they had subterranean transmission lines (which aren't preferred due to heat dissipation issues). So a screw-up here means somebody's getting called into a supervisor's office for a chat.
Until this problem was solved—and long after Tesla's AC based grids became the standard—there was no redundancy or ability to connect and leverage other grids. Whenever I look at those satellite maps of the abandoned Love Canal in New York State, I think how far we have come with our electrical grids.
Here's a great video that explains and illustrates the problem and how you solve it in a way that the average guy can understand. There are even cooler demos in the latter parts of the series.
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