Anybody heard about this?
Long article, but if it's true it's not a good thing..........
http://www.jimstonefreelance.com/grid.html
Unfortunately, his basic premise - that there is no frequency variation & hasn't been for ever - is wrong. There will be a permitted tolerance of variation - IIRC here in the UK it's 50Hz +/- 0.3Hz; in the States it's 60Hz +/- some small figure. The reason why this must be is most obviously illustrated with two examples:
1) Consider your own (hopefully Lister[oid] powered) generator. Load it from zero to 3KW and you will see a drop in RPMS - even if it's a temporary drop & the engine recovers. Remove the load & the engine races, before dropping back. Each sag/surge cycle alter the frequency of the output.
2) Now consider the national grid, with all its megawatts of generator. At 7am, 10 million Americans in Califorina all switch on their coffee machines. The sudden 100-megawatt load causes the grid generators to sag - just slightly - before the steam turbines driving them ramp in the extra power required. An hour later, the machines are all switched off and the corresponding lightning of the load causes the generators to race - just a little bit - before the steam turbines are reigned in. Each sag/load will, just slightly, affect the grid frequency.
And that, ladies & gentlemen, is why powerstations have complex control rooms full of people 24x7; they are constantly trying to predict just a few seconds in advance how much power is going to be needed, & are pro-actively adjusting the output to compensate. Here in the UK, we have a "coronation street" effect; about 12 million people in, say 8m households watch Coronation St, 3 times/week. 15 minutes in, the ad break comes on; and in a very siginificant number of those 8m households, someone will jump up & switch a kettle on. The resulting massive surge of power requirement would, if ignored, cause the grid frequency to drop sharply, as well as the voltage, causing brown-outs & other undesirable effects. However, the power station people know it's due, so just as the ad break starts, they switch in extra capacity to take up the load. I'm sure America has similar predictable surge loads, which are handled in the same way.
Anyway, the upshot is, the author's claimed "60hz, rock steady, never changing" grid frequency is rubbish. Yes, your kitchen cooker & some older mains-powered clocks may have used the grid frequency to keep time; but any critical clock has been synchronised by atomic decay for years; and nearly all other clocks are regulated by quartz.
Must admit though, the article's great for a laugh. I'll forward it on to some of my pals in the electricity industry, I think they'll find it hilarious.
