It is interesting - though I must say have not seen a mains derived electronic clock for years - quartz crystals are pence in bulk.

Mechanical generators slow down and generate a  lower frequency as the load current rises, and we can use that to sychronise a generator into phase -lock with an existing supply - you get it nearly synchronised so the difference frequency is sub Hz, and close the breaker, and the current that flows either adds or subtracts some torque, and in turn speeds up or slows the rotor until things settle to exactly the same frequency, and a voltage and phase offset that represents the fraction of the load handled by that one generator relative to the average of the rest.

There is an assumption in the way that the rules of the grid are written that all generators do this, but of course inverter derived things like solar farms, and most wind turbines (certainly those at the end of DC links...) have no such characteristic, the voltage droops as more current is taken, but the zero crossings occur where ever the electronics tells them it is time to invert the DC to do the other half cycle - Imagine if you will a big battery and a reversing switch operated at 100 times a second (as a full cycle is 2 reversals.)

It is possible in software to alter the timing of the zero crossings, either in a phase shift way, i.e. a one time shift and then a constant period again, or in a frequency shift way (all cycles have the new period.) and right now we go to some effort to make these inverter sources mimic the behaviour of a traditional generator, but it is not clear if as we may soon approach a situation with more kit on the grid emulating rotating generators than actually are, we wish to continue.

It may end up like the phone system with electronics at one end pretending to be a mechanical exchange, and stepping up to a really awkward 50V and 80V ringing   voltage, while at the other end we have phones containing electronics emulating a carbon microphone and a moving iron earpiece stepping down from this really awkward voltage to handle audio at lower levels internally. If we were starting again, this is not the system we would design.

Traditionally with comms systems inefficiency like this is a secondary consideration after compatibility and usability,   it is not clear that it should be for power system like a national grid.

It is interesting - though I must say have not seen a mains derived electronic clock for years - quartz crystals are pence in bulk.

Mechanical generators slow down and generate a  lower frequency as the load current rises, and we can use that to sychronise a generator into phase -lock with an existing supply - you get it nearly synchronised so the difference frequency is sub Hz, and close the breaker, and the current that flows either adds or subtracts some torque, and in turn speeds up or slows the rotor until things settle to exactly the same frequency, and a voltage and phase offset that represents the fraction of the load handled by that one generator relative to the average of the rest.

There is an assumption in the way that the rules of the grid are written that all generators do this, but of course inverter derived things like solar farms, and most wind turbines (certainly those at the end of DC links...) have no such characteristic, the voltage droops as more current is taken, but the zero crossings occur where ever the electronics tells them it is time to invert the DC to do the other half cycle - Imagine if you will a big battery and a reversing switch operated at 100 times a second (as a full cycle is 2 reversals.)

It is possible in software to alter the timing of the zero crossings, either in a phase shift way, i.e. a one time shift and then a constant period again, or in a frequency shift way (all cycles have the new period.) and right now we go to some effort to make these inverter sources mimic the behaviour of a traditional generator, but it is not clear if as we may soon approach a situation with more kit on the grid emulating rotating generators than actually are, we wish to continue.

It may end up like the phone system with electronics at one end pretending to be a mechanical exchange, and stepping up to a really awkward 50V and 80V ringing   voltage, while at the other end we have phones containing electronics emulating a carbon microphone and a moving iron earpiece stepping down from this really awkward voltage to handle audio at lower levels internally. If we were starting again, this is not the system we would design.

Traditionally with comms systems inefficiency like this is a secondary consideration after compatibility and usability,   it is not clear that it should be for power system like a national grid.