After the power outage in North America a few years ago most utilities no longer run their generators on voltage control, they run on power factor control and one power plant controls the voltage. Why? If all the generators are set to voltage control and a plant goes down, the smaller plants try to maintain the line voltage which makes them over load and trip out. This is what caused the big outage here.
Now the line voltages vary a lot more than they used to. Add in solar and wind from the individual consumer putting power back on the grid and not all the these systems regulating well (think cheap gear) and the issue is compounded.
I like the resistor. Simple solution for a simple problem.
Mike
Now the line voltages vary a lot more than they used to. Add in solar and wind from the individual consumer putting power back on the grid and not all the these systems regulating well (think cheap gear) and the issue is compounded.
I like the resistor. Simple solution for a simple problem.
Mike
Actually solar inverters do not regulate voltage in that sense. They just follow the line voltage, keeping their output just above that so that they can deliver power to the grid. Basically they just keep pushing up the voltage until they can deliver all the power coming from the panels, or until the upper voltage limit is hit. In the Netherlands it is mandatory to have them configured in such a way that they shut down when the line voltage exceeds 253V.
So they don’t regulate or follow, no they meanwhile lead and “compete” with eachother. True nitwits have requested to up the limit to 264.5V so they can keep earning money, pardon, can keep feeding green energy to the grid.
Just think of the implications of 5 minutes 264V on your audio 😊
@ Mike Gergen: it is suprising to read the standard method over there was exactly the one that leads to failure. Turbines and gensets are usually set to keep power till the limits and not to shut down. A chain reaction is the last that is wanted certainly when power stations need electrical power to start up (this is reality today).
Just think of the implications of 5 minutes 264V on your audio 😊
@ Mike Gergen: it is suprising to read the standard method over there was exactly the one that leads to failure. Turbines and gensets are usually set to keep power till the limits and not to shut down. A chain reaction is the last that is wanted certainly when power stations need electrical power to start up (this is reality today).
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Thread jacking;
Some governments have contracts with the utilities as to how power is delivered. Before the black out in 2003 small utilities and peaker plants would operate in voltage out mode. Exactly like you mention with solar. So what happens if the main generator, the unit that controls the frequency and voltage goes off line when they are all in voltage mode; The small units try to keep the voltage at the set level, they can't. the excitation on the generators goes up and up to increase voltage until they overload and quit.
This is what I mean by the cheap solar units not having good regulation. You can't have everyone trying to up the voltage, you see the result.
What is supposed to happen today is one generator in a section is the control generator, also called the black start unit, all others follow it. If the black start unit stops the others will just continue and let the voltage fall but the power grid stays up. This is called droop mode. This is what most governments contract to do today to prevent another 2003 incident.
Back to your scheduled broadcast.
Sorry.
Some governments have contracts with the utilities as to how power is delivered. Before the black out in 2003 small utilities and peaker plants would operate in voltage out mode. Exactly like you mention with solar. So what happens if the main generator, the unit that controls the frequency and voltage goes off line when they are all in voltage mode; The small units try to keep the voltage at the set level, they can't. the excitation on the generators goes up and up to increase voltage until they overload and quit.
This is what I mean by the cheap solar units not having good regulation. You can't have everyone trying to up the voltage, you see the result.
What is supposed to happen today is one generator in a section is the control generator, also called the black start unit, all others follow it. If the black start unit stops the others will just continue and let the voltage fall but the power grid stays up. This is called droop mode. This is what most governments contract to do today to prevent another 2003 incident.
Back to your scheduled broadcast.
Sorry.
Yes I know droop mode as default mode. I guess I did not read 2003. That is a long time ago. What I do know is that Diesel generators that support the grid operate like that here but solar doesn’t. This surprised me together with the apparent laissez faire attitude towards solar. The last course I did was last year and then suddenly regulations were carved in stone. Some large solar fields were even rejected and shut down.
What do you mean with “your scheduled broadcast”?!
What do you mean with “your scheduled broadcast”?!
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Just quickly drop in here - many recent solar inverters support Q(U) - so effectively they can lower the AC voltage while operating. If you happen to have an inverter from "F......" just drop me PM if you need assistance setting that up.
We had supplied 50W LED flood lights to an aluminum extrusion plant...sudden series of driver failures.
We put 100 or 10 ohms 10W ceramic fusible resistors in series with mains wire, problem solved.
The drivers were 90 to 270V, so we chose a resistor that would give 160 or so at normal times, so no issues there.
They had their own high voltage connection, meaning from secondary on it was their equipment.
Unloaded transformers on night shift can go high on secondary voltages, they were seeing 310V at no load.
We said repair charges will have to be paid, warranty void.
It turned out that the lighting supplies were off the 3 phase bus bars in the shed, and the single phase voltage regulator was for the office block next door.
Smart *****. No idea how much other equipment was damaged by their stupidity.
I agree and support your decision.
We put 100 or 10 ohms 10W ceramic fusible resistors in series with mains wire, problem solved.
The drivers were 90 to 270V, so we chose a resistor that would give 160 or so at normal times, so no issues there.
They had their own high voltage connection, meaning from secondary on it was their equipment.
Unloaded transformers on night shift can go high on secondary voltages, they were seeing 310V at no load.
We said repair charges will have to be paid, warranty void.
It turned out that the lighting supplies were off the 3 phase bus bars in the shed, and the single phase voltage regulator was for the office block next door.
Smart *****. No idea how much other equipment was damaged by their stupidity.
I agree and support your decision.
Strangely the 253V inverter limit forces the inverter to completely shut down, according to the EU standards and local country standards. The 2013 australian standard called out for a soft powering down when 253 volt was neared. This would allow the inverter to regulate its power when 253 was neared, instead of a sudden shut down. In a later australian standard, this feature was removed. I placed a 10V stepdown autotransformer to my house entry to protect the older 220V equipment. luckily i am close to the distribution transformer, so my neighbours are not effected by my PV injection. In rural areas the weak grid and long lines do create often the 253V problem with large voltage jumps when the inverters suddenly turn off.
Posts split off from what was an audio thread. Keep any discussion non political. This thread may be closed in future.
Weissi posted (post is gone it seems?!) the necessity of inverters in some German states to have Q(U) implemented which is too complex for me to explain in English. It is voltage dependent blind power compensation. Some of the energy companies are fed up with the rising mains voltages and force Q(U) above 4.6 kW feedback.
https://www.epe.ed.tum.de/fileadmin/w00bzo/ptd/Forschung/StudieQU.pdf
Of course this comes rather late as solar had laissez passer in too many areas regardless of practical/technical drawbacks. Of course everybody now is nodding that problems have occurred 🙂 One of the prime examples of first acting and then thinking.
https://www.epe.ed.tum.de/fileadmin/w00bzo/ptd/Forschung/StudieQU.pdf
Of course this comes rather late as solar had laissez passer in too many areas regardless of practical/technical drawbacks. Of course everybody now is nodding that problems have occurred 🙂 One of the prime examples of first acting and then thinking.
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The german standard requires the inverters to limit the cosphi to 0.95. I always called it the hidden 5% energy tax. You never can get more than 95% of your inverter power useable as billable real power.
That is maybe because there is not enough demand at the time the energy is created. The largest flaw of the solar circus. The turbines need to be throttled, it is all not in the benefit of those that maintain the grid and are supposed to cater for Dunkelflaute.
Some of this would be fixed if renewables were only paid for continuous generation. So each installation has to have enough storage to supply power when it's not being generated.
Domestically, feed in payments should be stopped and homes 'encouraged' to install batteries
Exactly. It would have been nice if that would have been thought out like that when it started.
Accumulators are too expensive and should be supported by large capacitors.
Wind and solar power go into blockage or decline when we have too much production on the power line
Wind and solar power go into blockage or decline when we have too much production on the power line
We have available 'bicycle turbines' here, less than 2 kW, feeding 48 and 24 V battery banks, 150 Ah.
Some off grid users in USA use old submarine batteries.
Telephone exchange batteries are also popular as storage devices.
Hybrid controllers, capable of wind + solar, and grid connection are also available.
Some off grid users in USA use old submarine batteries.
Telephone exchange batteries are also popular as storage devices.
Hybrid controllers, capable of wind + solar, and grid connection are also available.
I've been seeing that on the TX grid the past couple of days now. Pretty extreme. They are throttling around 12GW at the moment and will for most of the afternoon. Yesterday was worse at more like 15GW throttled. But it is spring, windy, sunny and low demand. There is battery, around 4GW I think can be added/pulled, but not for sustained 4-6 hours. I see it peak at the morning transition where the NatGas is being turned down in anticipation of the sun coming up. I think this year has been worse than before, and not surprising, as more wind/solar has been added.