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Tôi tò mò về hiệu suất nguồn điện lưới ở TP.HCM trong thời gian khóa máy, vì vậy tôi đã thu thập dữ liệu.

Posted on by hoangct
27
Oct

Tôi tò mò về hiệu suất nguồn điện lưới ở TP.HCM trong thời gian khóa máy, vì vậy tôi đã thu thập dữ liệu.

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3 thoughts on “Tôi tò mò về hiệu suất nguồn điện lưới ở TP.HCM trong thời gian khóa máy, vì vậy tôi đã thu thập dữ liệu.”

  1. Saigonauticon says:

    EVN came and installed a new mains power meter before Covid. I noticed on the LCD it has a display, that sometimes shows the AC frequency (nominally 50Hz). During lockdown, I am very, very thankful to have electricity 😀

    So, this renewed appreciation for electricity got me thinking — how accurate is the phase measurement on that meter, anyway? So I measured it at a resolution of 0.0000005Hz, ~20 times per second for a few hours. The result was sort of neat — if you know what you’re looking for, you can see them turning on and off turbines to keep the power supply between 49.7 and 50.2Hz, with various things kicking in at different levels to accommodate people consuming varying amounts of power.

    How does this work? More or less I just make the mains power turn an LED on and off. That triggers a photodetector that sends a signal to a chip that handles the accurate time measurement, and outputs it to my computer (there’s a bunch of stuff to clean up the signal along the way, but it’s boring). This is a fun approach because the only thing connected to mains power is an LED, a power diode (the LED might not appreciate ~311V reverse voltage) and some resistors. Then the rest of the circuit is completely isolated from mains power, receiving information via light rather than electricity (optoisolation). Fewer electric shocks this way!

    Why would I have a time measurement system like that just lying around? Well… in 2011 I had designed a device to study the timing of anomalous geomagnetic events as part of an elaborate practical joke. It turns out it was also good for other things, and has made it’s way into substantially more serious applications. So definitely never give up being silly, you never know what you can learn along the way.

    Incidentally, I compared the data to the EVN meter and found it accurate down to at least 0.01 Hz (maybe better) with no significant difference between the two. It’s in a different room and the comparison accuracy is mainly limited by the speed at which I can run up and down stairs. Should have thought of that earlier I guess…

  2. thebesteverredditor says:

    You have way too much free time during the lockdown man, lol. With that being said, it’s a cool experiment there. And I guess the irregular oscillation is the biggest drawback of renewables as the grid will have to keep adjusting.

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