In article snipped-for-privacy@4ax.com, The Other Mike snipped-for-privacy@somewhereorother.com scribeth thus
Isn't the 400 kV grid carrying around half a GW per circuit or is it more now Mike?..
It does seem that this DC to AC inverter software circuitry needs some further though it's not that stable seemingly?
Come to think of it how does the inverter right out in the North see or know what the grids running at, or does it just ramp up frequency and see what currents flowing back to blighty?..
They could have a standard way to answer. It depends on whether the phone is 'asleep' or not when it 'rings'. You touch something, or swipe something /to the right/??
No. And there is a fundamenal point you are missing
It CANNOT be solved just with software.
A temeporaty rid overlaod must be covered either by a loss of load - load shedding or load reduction - or by an incease of power.
In general load reductiuon and slowering freqeuncy go together in syncrhonrous motors, and lowering volatges will in general lower to load with resistive lods. Not so with switched mode power supplies.
So what happens with spinnging nennies is that the rotational inertia os in fact kinetic energu and that is what represents the increase in power that will be fed into te grid. As the rotors slow, energy is lost, and that becomes what keeps the grid up. Until somethinmg else can. Like openeing the throttle on a coal or nuclear plant
Because steam boilers also represent energy storage too.
The point is this: althoiugh software that reads mains frequency and if it slows advances the phase of the inverters to feed more power in, are possible, there IS NO MORE POWER to be had!
Unless you strap lithium bastteries to the DC output of every wind turbine. Or supercapaciors. Or use a big f*ck-off rotary inverter. (DC from wind turbines drives DC motor attached to AC generators attached to the mains)
More expense. Less profit.
Phase is the issue.
Before connection the mains frequency and phase is read and the inverter will connect at slightly leading phase to it. So it draws power. Then the power in is monitored and the phase adjusted so that full power is delivered.
So it ramps up phase, not frequency.
The whole grid is phaselocked. If you want to connect a generator to it you MUST lock phase and advance it a tad until you are feeding it. At zero phase you are not delivering or taking pwer.
The problem is domestic inverters are set to trip out if the frequency drops too far as well as having no storage.
They are not serious generators. They are bolt on additions
It could be solved by not putting 100% of everything the wind farm generated out onto the grid or some local battery storage colocated. The latter would make some sense since then the large scale DC to AC grid tie converters could be used for two purposes.
A grid overload can also be handled by allowing the voltage and frequency to drop. Enough load is resistive that it should balance. It don't see any reason why an AC to DC converter can't track the phase right down to the point where conventional spinning kit begins to drop off. Injecting some power is better than injecting none at all.
But enhanced resilience against grid fluctuations. It may be a necessary thing to add to the larger wind farms so that they can output 110% for a brief 5 minute period when called upon to do so. Even a minute of extra reserve might well have been enough to prevent cascade failure.
I have my suspicions something wasn't configured right at Hornsea though and it tripped because the settings were essentially paranoid. It was a very long way away from the lightning strike and East Anglia was much nearer and stayed up as did the toy prototype version of Hornsea.
It is a large scale phase locked loop.
But I doubt they were a really significant factor in the overall cascade failure. Most domestic solar PV is rigged to make hot water and pocket the export FIT for 50% they never export!
More kit less reliability.. more faults that need to be handled.
I used to design fault resilient systems that are still in telephone exchanges now so I can assure you that you get to a point where you make the system less reliable.
I ma all for putting batteries in wind farms as long as I don't have to pay to fix their problems. I would rather build nukes and not have the problem in the first place.
Well in that case then perhaps they ought to keep a small amount in reserve say they have around 100 MW available send as it were 90 MW so they do have a reserve?.
Ain't happening is it?..
How do they determine what the load side is in an inverter system?
How's it do that without altering the frequency??
Indeed thats the way its done with alternators but are inverters exactly the same?..
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