Let’s say in an isolated area there are fifty homes and a power station capable of producing 1500kW per day. Each home consumes 30kW per day on average.
Now explain the following two situations to me like I’m 22.
1. A new home has joined the party. Will the power station be able to supply power to the new house or does it need to be extended its capability? Or an existing home decided to purchase a refrigerator, graphic card or whatever and increased their demand. How will the increased demand be fulfilled?
2. Twenty homes went on a vacation. So, 900kW per day is enough to full fill thirty homes’ needs. But the power station will continue to produce 15000kw as usual. Where will the remaining 600kw go?
I’ve given an analogy of fifty homes with 1500kW but compare the situation with a country. Not every house consumes the same amount of electricity every day. How do the government produce and distribute electricity in an efficient manner? Does electricity get wasted? Where does the extra electricity go? It is obvious that there is no big battery to store em! 🤷🏻♂️
In: 2
AC grids have a frequency (normally 50 or 60 Hz), which is the speed at which all the rotational generators are spinning on the grid (solar, wind, etc use digital inverters for this). Each generator works to maintain that frequency, when it’s spinning at that frequency it’ll produce it’s rated output voltage (which will be transformed up/down as needed).
So, you push down your toaster. A new path is opened up for current to flow, so say 10A @ 240v flows through it. At the generator, say it’s generating at 2.4kV that’s 1A of additional load.
That 1A will create a magnetic field in the generator that will directly oppose the movement of the spinning bit. The spinning bit will slow down slightly as a result.
In response to the slower spinning, the generators regulator system will increase the power to the generator – e.g. it will release more water from the dam, steam from the boiler, etc.
If you can’t do this fast enough (e.g. the boiler can’t heat up quickly enough, all the dams are maxed out) then you have a problem. The grid might ask big industrial users to reduce their load (e.g. if you have a giant fridge, you can turn it off for a bit without it loosing temperature).
If the frequency drops below the target it’s essentially a grid emergency. At this point an emergency load management system will do something drastic like cutting off power to a suburb (automatic load shedding).
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