smart meters resisted

And I struggle to see how an electronic meter could measure the total without measuring the 3 phases.
Indeed - but as I've just written, whether the integration of data from the three phases is done in hardware or software is a different question. If done in hardware, it would be unlikley that separate-phase data would be available (or stored in a register), wouldn't it?

However, no-one has yet addressed my implied question as to why there would ever be a need for separate-phase data.

Kind Regards, John
 
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They probably use current transformers on each phase and measure phase voltage directly.
Indeed, and there are a number of chips that will do all the work for you - some which make many measurements per cycle and work out instantaneous power, which they sum over a cycle. Thus they can provide accurate real and imaginary power measurments for complex (non-linear) loads.

Hope the meters are more accurate.
You'd hope so. There are very strict limits for accuracy - but that doesn't always mean the limits are met. In that case, the problem was with the use of Rogowksi coils which require an integration step to get power - and any offset errors get integrated into false readings.
 
I wonder about the recalibration interval. As software is bound to be available it can also be used for actual calibration but I'd hope they still use very high quality components even if they are not precise values. They must have a very stable voltage reference involved - ;) off hand i can't remember the long term stability of what they probably use. That may well be used to check internals indirectly. A lot of thought has probably been given to them to ensure we don't get cheaper electricity. ;) Who knows the other way. No idea what meter specs say.

And the answer to JohnW2 question is because they can and some one decided to do it. I suppose in areas where mixed single and 3 phase is used it could be of interest but that is usually accommodated by the wiring.
 
And the answer to JohnW2 question is because they can and some one decided to do it. I suppose in areas where mixed single and 3 phase is used it could be of interest but that is usually accommodated by the wiring.
Perhaps, but I still don't really understand the 'why?' (given that it presumably comes at a cost). Suppliers do not care what might be 'of interest' to their customers, their only interest in meters (at least, at present) being in relation to metering/billing - and, as I've said, I can't think of any situation in which they would want to charge differently for electricity used on different phases.
 
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The work and cost will be associated with the fact of having a display and button(s) in the first place and measuring. ;) Unfortunately or otherwise I used computers for modelling long before people generally new they existed. The company moved me on to different things several time the last one was electronics and software firmware in this case. :( They even sold me part way through that. So seriously if some one knew that they were going to do that it wouldn't be a significant addition. That would also apply if asic's were used.

:) I've been wondering if it's possible to hack them. No doubt eventually some will try.
 
The work and cost will be associated with the fact of having a display and button(s) in the first place and measuring. ... So seriously if some one knew that they were going to do that it wouldn't be a significant addition.
Yes, but as I keep saying, that depends upon whether or not individual phase data is available for the software to process. If the phases are normally combined in hardware (e.g. one of Simon's 'chips'), then it might not be quite so easy.

... but I still don't understand the circumstances under which a supplier would want to charge differently for consumption on different phases. That would mean, for example, that in a street of single phase installations (with 'cycling phases'), one would be paying a different price from either of one's neighbours!
 
I've been wondering if it's possible to hack them. No doubt eventually some will try.
People will try.
That's one of the reasons SMETS1 meters can't all be upgraded to work with current systems - they don't have the encryption capability to talk to the secure network. Apparently GCHQ were involved in the security design - after the original security was found to be "not robust". Some SMETS1 meters can be upgraded with a new comms module, many will need to be replaced - so much for early adopters of smart meters. And I believe SMETS1 meters were still being installed into last year.
Of course, we are expected to believe that this massive system, with something in the order of 60 million devices (almost all lacking physical security) connected to one end, and many suppliers all connected to the other end, and many meter operators involved, and god knows how much information - will be 100% secure for all time. Yeah right :rolleyes:
I suppose it will probably be "secure enough", but that's not really an excuse for storing something in excess of 50k records per customer (48 records/day * 2 meters * 365 days/yr * a couple of years ) - so over 2,000,000,000,000 records in one big database. What could possibly go wrong :whistle:
 
... but I still don't understand the circumstances under which a supplier would want to charge differently for consumption on different phases. That would mean, for example, that in a street of single phase installations (with 'cycling phases'), one would be paying a different price from either of one's neighbours!

I don't see why they would want to do that either. As far as I am aware street wiring usually is 3 phase. Houses are wired in to distribute the load over all 3. This can be seen some times when a single phase goes down. Some street lights go out as does the lighting in some houses.

Normally a 3phase meter is used for providing 440. 240v will also usually be needed. Traditionally 110v as well. I bought a static single phase 240 to 440v 3phase converter because of the length of cable that would be needed to get 3 phase to the garage when I had a 3 phase lathe in it. :( Now I sort of wish I had gone for 3 phase. At the time it would probably been cheaper than the converter and I would have had just a single meter not long after we moved in. My reason for wondering about 2 phases on a meter is down to maybe needing a true higher amperage supply in the future. 2 phases are still there, just the fuse has been removed. While they would probably fit a 100A fuse to the single phase we now have no way would it be a true 100A supply as the voltage drop would be too high.

Actually one of our phases went down. Daylight so wondered if the fuse had blow so took it out to check. Found it was ok so phoned them and they got a bit excited about me replacing it myself so sent 3 people out in a car. 2 suites and one not so well dressed that had the stuff to reseal the fuse in his pocket. The suites weren't keen on doing anything with it so the other bloke offered.
 
I don't see why they would want to do that either.
Quite.
As far as I am aware street wiring usually is 3 phase. Houses are wired in to distribute the load over all 3.
Indeed. That why I said that if they charged differently for the phases, both of one's neighbours would probably be pay a diffent price from what one was paying, and that would be ridiculous. ... and if it's ridiculous for three houses on different phases, it would also be ridiculous for three phases supplying a single building.
Normally a 3phase meter is used for providing 440. 240v will also usually be needed.\
In industrial, and some commercial, installations, yes. I have a 3-phase supply to my domestic property, and that is used to provide three single-phase '230V' supplies (roughly 'one per floor').
 
In industrial, and some commercial, installations, yes. I have a 3-phase supply to my domestic property, and that is used to provide three single-phase '230V' supplies (roughly 'one per floor').

;) I'm not so greedy. 2 phases spread over 3 floors would do me. That's assuming we ever wanted to use electric heating. 1 phase for that would probably be ok with the other for the usual things.
 
3 piece suites in one car? Must have been a big one

No medium sized car driven by the one that refitted the fuse - probably to allow him to get some car mileage allowance and probably the only one that had actually ever done any electrics.
 

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