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The Mysterious Electric Grid

  1. Sep 14, 2016 #1
    Hello Physics Forums, this is my first post!

    I wanted to know how the current electrical grid system works. I mean, not in terms of creation, transmission, and distribution, but rather, how you would draw it on a circuit diagram. I understand that an AC current is generated at the power factory (or power factories) but how does that make it to my power socket? Also how does it not, when my switch is turned off?

    It would be awesome if you could also answer how the electricity company measures my consumption of electricity.

    Thank you for answering, I will appreciate any input on it :smile:. You see, I was not able to find very good information on the internet, even after many hours spent researching related things.
  2. jcsd
  3. Sep 14, 2016 #2


    Staff: Mentor


    This Insights article will answer some, but not all of your questions.

    On Physics Forums it is usually best to ask only one question per thread.
  4. Sep 14, 2016 #3
    Thank you very much for that link, I am halfway through it, and it is very informative. I will ask one question in my threads from now on.
  5. Sep 15, 2016 #4
    Since you asked about drawing circuits, the industry standard is to use one-line diagrams for drawing distribution level circuits. These diagrams simplify the drawing of 3-phase systems. As the name implies, in one-line diagrams you can group multiple wires into a single power bus. Three-phase transformers become single units. It would be a real mess if you actually drew the entire circuit with all the transformer taps, fuses, disconnects, and panels. It wouldn't make much sense at all. You can find plenty of one-line (single-line) examples from a Google search.
  6. Sep 15, 2016 #5

    jim mcnamara

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    Staff: Mentor

    WECC maps (maps of the Western US grid) show simple lines for large transmission lines, for example. Even though I worked in power for years, it has now become harder to get access to accurate data or maps. FERC and NERC (agencies that oversee the grid) have tried to lock down this kind of data since 9/11.

    I have not seen an electric grid map since 2009 when I moved to gas only. However there were points on the map that even people like me could see where an attack would have massive consequences. There has been work since then to improve things.

    Read this to see how a software bug at one electric company brought down Major parts of the US Northeast grid, and the part of the grid in Canada.

  7. Sep 16, 2016 #6

    jim hardy

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    Science Advisor
    Gold Member

    You might enjoy watching the grid shift power between regions

    select "us frequency gradient map" which shows frequency changes
    though something is wrong with it, it shows 'way out west' always running slow
    but it's still interesting to watch frequency hunt around 60hz, demonstrating the grid is a dynamic almost living thing as per Anorlunda's insights article....

    or select "angle contour map" where red-ish regions are shipping power into blue-ish regions

    displays of captured grid upsets are fun to watch.

    old jim
  8. Sep 16, 2016 #7


    Staff: Mentor

    Once again, @jim hardy found an excellent web resource. But my favorite on that site is the "captured grid upsets" that Jim mentioned. In particular, the event below is very instructive. It shows how a local event (a tornado) causes the grid over a wide area to respond.

    Turning off a light bulb, is like the tornado event in miniature. And yes it is true that turning off a light in Kentucky slightly alters the power flow on every power line from Kansas to Maine. In Europe, I could say a light bulb in Kiev effects every power line between Siberia to Spain. And those power flow changes influence frequency.

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