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Why is the European mains voltage so well regulated?

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treez

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Hi,
There is no formal regulation on the mains, so how does it manage to be so well regulated?
In Germany (Bavaria) over a long weekend, the mains was pretty much totally between 226-232VAC at a domestic outlet.
(VAC readings taken every minute)
All readings were within 220-235VAC.
You would think there would be serious ir drops where there is lots of kit simultaneously switched on , on the same phase, and the mains would drop...but this doesn't happen...why?
 

Hi,
There is no formal regulation on the mains, so how does it manage to be so well regulated?
In Germany (Bavaria) over a long weekend, the mains was pretty much totally between 226-232VAC at a domestic outlet.
(VAC readings taken every minute)
All readings were within 220-235VAC.
You would think there would be serious ir drops where there is lots of kit simultaneously switched on , on the same phase, and the mains would drop...but this doesn't happen...why?

Low resistance wire?
 
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Here in Canada my mains is always 121V. The transformer for mine and 7 other homes is next door on the boulevard, the wires are underground.
In countries on the other side of the world the voltage varies all over the place and is cutoff every day because people there climb the poles and steal electricity using their own wiring.
 

I would guess it has a lot to do with the interconnects between countries. Electricity supply doesn't stop at borders in Europe so the load is very well shared. The technology in Europe is also well developed and there is plenty of capacity for load increases. Even here is rural Wales, the nearest power station can go from standby to 1.2GW output in a few seconds. It is hydroelectric and I've stood beside the water flow valves - it is quite scary! Well worth a visit if you are in this area, it is open to the public.

Brian.
 

Hi,

There are many power distribution plants with voltage regulation in Germany.
And several frequency regulation plants in Europe.

Klaus
 

There is no formal regulation on the mains, so how does it manage to be so well regulated?
In Germany (Bavaria) over a long weekend, the mains was pretty much totally between 226-232VAC at a domestic outlet.

I do not think it is appropriate to rate the quality of electric energy in a community of countries by taking only one sample as reference to extend the conclusion to the whole continent. On a trip I made to Switzerland 14 years ago, I witnessed a brief blackout of energy in the region where I were hosted, an extremely rare event in that country as I was informed later, and I did not take it into account to qualify the electric energy distribution there. Fact to consider, is that the services destined to the public with individual facilities are subject to frequent deploy/uninstall and it is supposed to have a spot imbalance, but on the other hand a continuous monitoring from the operator company so that points momentarily outside the curve are predictable to happen and to be corrected; in short, a dynamic process.
 

I think of us consumers asking for more power to our appliances, as we reduce load resistance seen by the electric company. Normally this causes voltage to droop, except that they bring up another generator. In this way they reduce their own source resistance, and restore balance with customers' reduced load resistance.

The electric companies anticipate power demand hour-to-hour and they turn generators on or off. I have trouble thinking of an easy way to modify voltage at those massive power levels.
 

In countries on the other side of the world the voltage varies all over the place and is cutoff every day because people there climb the poles and steal electricity using their own wiring.

I am on the other side of the world; but most of the world's people live here!

The basic problem is not theft; it is the network. The networking of multiple generators need attention to details.

If a circuit has two voltage sources (AC), they must be matching well in phase, frequency and amplitude.

Even a small difference in frequency can cause a large shift in phase over a number of cycles.

Amplitude is less critical because of intervening power transformers that can absorb 5-10% loadside variations.

With the distribution transformers, we also have both overvoltage and unvervoltage cut-offs. But they are mostly disabled "on this side of the world" (I speak only about a small part of this side).

My power is regularly interrupted at least once a day (for about 1-2 hours). People who live in the country side (say about 100 km from my home) get power about 1-2 hours a day (not all but many).

Our power comes from local generators and not from any national grid.

- - - Updated - - -

the nearest power station can go from standby to 1.2GW output in a few seconds.

It is possible but unlikely that 1.2GW is coming from a single generator; perhaps 2-3 or even 4 generators are involved.

I am no expert but a few seconds is possibly a figure of speech; generator output needs to stabilize before the circuit breakers will connect the output to the load. It may take several minutes. They will not reach the operating speed in a few seconds.

But there are prediction algorithms that can trigger a standby generator in action. Generators have plenty of headrooms in Europe.
 
I am no expert but a few seconds is possibly a figure of speech; generator output needs to stabilize before the circuit breakers will connect the output to the load. It may take several minutes. They will not reach the operating speed in a few seconds.
It is actually surprisingly true, each set is a pump/generator and when in standby there is no water in the turbine, forced up the tailrace tunnel by air pressure and the motor is connected to the grid so it is running at synchronous speed with a slight lag. The intake valves have to be seen to be believed they are the biggest ball valves I have ever seen, they are operated by massive weights and a pair of big hydraulic rams, when the go command is received the valves fully open in a fraction of a second, the water enters the turbine and the motor/generator goes from lag to lead (generating) in somewhat less than 2 seconds. There are 6 sets each around 300Mw and I was lucky enough to be there when four of them were triggered to go online simultaneously, I can assure you the earth moved, or at least the concrete platform I was standing on, that's an awesome amount of water under very high pressure.
It used to be called the Dinorwic pump storage scheme but these days I think it's styled as electric mountain, in North Wales :)

Within the grid there are lots of automatic tap changers on transformers and automatic harmonic and power factor correction units all of whom help to regulate voltage. Most substations also have fixed tap changers that are altered from time to time to account for local changes such as attaching additional loads (housing developments etc). Most countries have fairly tight voltage requirements although in the vicinity of rapidly changing heavy industrial loads (strip mills, furnaces etc) there may be short term out of band excursions but this is becoming a rarity as such production moves offshore.
 
Hi,

Afaik: For voltage regulation one uses transformers with several taps. This is technically relative simple, but for sure it's some effort. Thus it's not in every small village. I don't have exact values but I think it's done for units greater than 1 million households.

Frequency regulation is more difficult. The frequency of mains is a measure of the imbalance between demand and production of energy. Most of Europe is connected with one big grid. Thus the frequency in whole Europe is the same. It's not possible that within one grid there are two places with different frequencies. In Europe there are just a couple of "fast power plants" to maintain frequency stability. They regulate in a couple of seconds. And can deliver as well as draw energy.
Read details: https://www.mainsfrequency.com

Klaus
 
Electric Mountain (Dinorwig) is the generator I was referring to. Its an amazing feat of engineering and virtually the whole power station is built inside a mountain. From the outside, apart from the visitor center there is almost no evidence it exists. It has one of the biggest man-made caverns in the World and uses pumped storage, rather like a giant battery to keep the grid stable. At times of low demand the turbines work in reverse to pump a low lake to a high one then at peaks it uses gravity to drain the high lake back down again to produce power.

Another eye-opener is to visit the grid control centers. At one central location they can monitor the load at thousands of points within a huge radius and adapt the power routing to level the supply to meet demand. They even take into account TV program schedules so they can prepare for demand peaks in commercial breaks and at the end of popular programs.

Most of Europe has a very advanced power grid which explains its reliability, I appreciate some countries have smaller and less cooperative schemes. I think the peaks in posts about mains inverters on Edaboard around times of hardship in some countries is testimony to that.

Brian.
 
It is actually surprisingly true, each set is a pump/generator and when in standby there is no water in the turbine, forced up the tailrace tunnel by air pressure and the motor is connected to the grid so it is running at synchronous speed with a slight lag...

Impressive indeed!

There is an wikipedia article on this and there are extensive references and details. Basically a super UPS!!
 

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