I know that hydro generators can provide inertia to grid. But what about pumped hydro when it’s charging?
Say on sunny afternoon when 100% of electricity is generated by solar but there is like GWs of pumped hydro is charging. And suddenly some solar farms disconnects from the grid. Would this cause a blackout?
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> But what about pumped hydro when it’s charging?
They can, but it’s hard to predict whether your scenario will cause a blackout.
Don’t forget there’s also electrical machines on the consumer side that provide inertia, and there’s still load shedding to prevent blackouts even when demand can’t be met.
There is more than one pump so you could take and receive energy at the same time if required.
Sure, three phase motors count for inertia, particularly if directly connected. Not a lot of difference between a synchronous motor and a generator from an electrical perspective.
> Does pump hydro provide grid inertia specially when it’s charging?
No
Yes, pumped storage does provide grid stability (technically reactive power) when pumping. This is usually after the evening peak, so the grid is more stable.
If you lose generators while pumping, the pumped storage units will automatically disconnect from the grid when the grid frequency drops too low.
Loads can lend grid inertia in that they can help to mitigate a frequency perturbation higher than the grid standard frequency.
But that’s not the major risk that the grid faces, and that’s not what grid inertia is for… it’s for mitigating frequency perturbations lower than the grid standard frequency, and only spinning-mass power-producing generators can currently do that.
Inverter-based generators can provide simulated grid inertia, but it’s not the same as actual grid inertia… specifically, if the inverter-based generator is heavily loaded, it can provide less simulated grid inertia. IOW, right when grid inertia is most-needed (high grid load) is when inverter-based generators can least provide it.
In order to ensure that inverter-based generators can always provide sufficient grid inertia would necessitate lightly loading them… which means building even more of them, which means even more cost, which means even higher retail electricity prices.
One way of getting around that for, for instance, wind and solar, is to have those power a motor-generator with similar spinning mass as a traditional power plant… if the sun goes behind a cloud bank or the wind stops blowing, the motor end of the motor-generator goes dead, and the generator end becomes a motor to draw just enough from the grid to keep the motor-generator set spinning until the power comes back to the motor end. Thus there are less-abrupt power (and thus frequency) perturbations which conventional spinning-mass generators can mitigate (unless there are simply too few grid-inertia-contributing power sources to keep the grid up, in which case you get the cascading trips as we saw in Spain, which exacerbates the frequency perturbation).
Any adjustable load can provide some form of inertia to the grid. If you have the proper algorithm to adjust the load as needed.
This is not actual inertia, more like load shedding, but the inertia itself is the algorithmic model with the load being the actuator. It’s the exact opposite of base load power generation, this would be base load power consumption. With the added advantage of the power being stored.