Back in 2015 Turkey has been synchronized to the European grid.
Now my question is, how do you synchronize a whole country to another country? Adjusting the voltage is pretty simple by using transformers, but what about the frequency and phase angle? While synchronizing a generator to the grid is just a matter of changing the rpm of the generator, but obviously you can’t do that, in order to change the frequency of the grid, because if your generator is to slow it will be powered by the grid. So how do you synchronize a whole country?
In: Engineering
When you connect two generators together, they become locked together. They both turn at the same speed and they remain phase locked together.
If one is slower than the other, it will act like a motor, pulling power from the other one to speed up. The other one will slow down under load. In practice, you want this to be a controlled process. If you just randomly connect a generator to the grid (which is much bigger and much stronger than one generator), it will yank the newly connected generator so hard that something will probably break.
So, if you want to connect a generator to the grid you have to synchronise it. You measure the grid voltage and generator voltage. You then adjust the generator voltage, by adjusting the generator exciter, until it matches. You then measure the grid frequency and phase, and the generator frequency and phase. You adjust the generator speed up or down by adjusting the throttle, until the frequency and phase match very closely. Then once they are matched, you close the circuit breaker to make the connection. Once connected, they become locked together.
Once synchronised, the generator throttle control controls the amount of power exported to the grid, and doesn’t do much to frequency. The generator exciter control controls the amount of reactive power imported or exported to the grid.
It’s very similar when you synchronise 2 grids. You have a circuit breaker connecting them together. You keep it open.
You adjust the grid voltages until they match by adjusting “reactive power” – which can be done by having individual generators on each grid adjust their excitation controls, or by using separate “compensation” equipment on each grid.
The you adjust the frequency and phase of each grid. This is done exactly the same way as adjusting frequency and phase of a generator. You adjust the throttle controls on the individual generators, and this will very gradually shift the grid frequency and phase. The once the frequency and phase are matched, the circuit breaker is closed joining the two grids and the two grids will now stay synced by transferring power across the link.
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