Utility Billing KWH/ Measures in KVA but bills in kWh

snipped-for-privacy@ipal.net wrote:


Quite right. And the inductance in step-down transformers. Capacitor banks are one of a variety of schemes that falls under the general heading 'voltage support' services. Synchronous motors is another. And having the ISO control the amount of MVAR carried by various generation units as well.
But 'Dummy' apparently thinks all customers are required to correct their own pf. So why there is any MVAR load is a mystery (at least to him).
daestrom
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On Sun, 15 Jun 2008 12:08:06 -0400, "daestrom"

The word for the day is governor.
You know, the little device on the musical box which makes it play at the right speed, regardless of the spring tension... the similar device on a generator that keeps the shaft speed constant.
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ItsASecretDummy wrote:

Ah, so now we see you can't even tell the difference between frequency and voltage??
Or are you saying the governor is the reason there is any MVAR load?
Either way, you're clueless.
daestrom
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On 15 Jun 2008 14:59:26 GMT, snipped-for-privacy@ipal.net wrote:

Or perhaps the inability of some metering to "read" power where there are huge phase differentials between the current and the voltage.
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ItsASecretDummy wrote:

Don and I *know* why power companies use capacitor banks. And it often is *not* because the customer has a poor pf. If you knew much about power distribution networks and voltage-support schemes, you wouldn't even be trying to argue your lame points about customers being required to pf correct. But you've been claiming that *customers HAVE* to pf correct.
daestrom (hint: How do you keep the voltage at the load end of a step-up, transmission-line, step-down transmission line without having an overvoltage condition at the upstream end? When you know that, come back and chat)
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On Sun, 15 Jun 2008 12:02:19 -0400, "daestrom"

I worked for a power supply company, dipshit, and nearly ALL of our customers wanted PF correction for AC fed devices, and many if not most were required to specify such features when they asked us to quote a power supply design for them. Integrated supplies are usually fed DC so pf correction would come before those supplies.
In particular, military, medical, scientific, and government customers want pf correction. Also any commercial planner with any brains would choose it.
So yes, building facilities personnel make considerations these days for keeping their pf as low as can be feasibly managed, which included paying us extra to design pf correction into our supplies.
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ItsASecretDummy wrote:

Ah... the truth comes out. You worked for a company that makes electronic power supplies. That explains a lot of your ranting. Typical switching power supplies that use a rectifier to convert line AC to DC as one of the first stages have terrible harmonic content and thus a low power factor. And so, many designs are used to correct this to remove the high harmonic content (or at least prevent it from propagating back to the supply panel where it can affect other loads on the client's premises)
You know what 'Dummy'? The low pf from a couple dozen such power supplies is a drop in the bucket to the VAR loading from a couple of good sized motors. Same thing with CFL's. It would be very rare day indeed that the poor pf from such small loads ever was much concern to utilities.
Biggest issue with the harmonic content from those sort of power supplies isn't the impact on the utility but the impact it can have on another customer's equipment. Or affecting other equipment in the same building.
"Large" installations of such power supplies can be a bit of a problem for three-phase systems as the current in the neutral line can be higher than any one of the phases and overload the neutral. That's a customer problem, not a utility problem.
The revenue metering for even a 'large' installation of such power supplies is still rather trivial. The kWhr meter will measure energy usage without any special 'correction'.
And certainly is *not* the reason utilities put in capacitor banks.

Right, who in their right mind wants '...their pf as low as can be feasibly managed' ??
daestrom
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It is not to correct their power factor. It is to correct how their meters read their true usage.
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ItsASecretDummy wrote:

You *still* haven't a clue about how a kWhr meter can read actual energy flow regardless of the power factor. I think it was Westinghouse that invented the darn thing a hundred years ago. Long before pf-correction was even a twinkle in anyone's eye.
There is no need for 'correction' for a kwh meter to properly read just what it is intended to read, kiloWatt-hours.
daestrom
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| Industrial demand metering measures peak KVA demand -not power factor.
This would be a measure of the distribution equipment capacity you need. The power company may choose to overbuild your feed, and the overall distribution of the network your feed taps from, and charge you for having it at the rate applicable to the capacity you need.
| Energy metering inherently measure the kWh used without the need for a power | factor "correction".
This is, of course, the electrical energy you use.
| This is no different now, except for the metering equipment, than it was 70 | years ago. | | Customer loads do not "have" to be pf corrected. If low power factor at the | loads add to the peak demand KVA (and this may not be the case) then it | would be economic for the customer to add some correction such as | capacitors or even synchronous motors. If the low pf is at a light load | time, it may not be worth the effort. It is not a great task to decide what | is the optimal correction (which will not be to unity pf) for a given | situation.
Still, there is some slight energy loss due to low pf. With the low pf the current is higher relative to power actually being used, and the voltage drop losses are therefore higher. But is the percentage of this loss enough to worry about? Probably not. Still, modern digital meters can easily (if so designed) measure a lot of things, including average watts, average VARs, peak watts, peak VARs, peaks per phase, peaks of phase sums, etc. Things with the big costs (capacity maintenance and energy) would be what they want to measure.
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Especially the modern, digital versions.
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clydebeer wrote:

TEST
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Why make a sane post, and then follow it with this retarded horseshit?
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You will have either a kWh meter + a peak KVA demand meter, or the two will be combined in a single instrument which will read both the actual kWh used (as in a standard watthour meter) as well as the peak KVA during the billing period. The peak reading part will have a lag (typically 15-30 minutes) to reach the actual value) so that it doesn't respond to short term peaks such as motor starting which have little effect on equipment ratings. Older KVA meters simply had a pointer (with thermal lag) which pushed another pointer leaving it at the peak position to be reset by the meter reader). The meter does not need to read power factor.
Example: 2400kWh/day
a) constant load of 100kW at unity pf --- supply rated at 100kVA capacity b)same load, power factor 0.6 or net 166kVA supply needs to be 66% larger c)same load, unity pf but concentrated for 8 hour of the day. 300kW 00kVA supply required
The energy charge as read by the kWh part of the meter is the same in all cases but there is an additional charge based on the peak demand kVA reflecting the cost of the supply equipment.
Your bill "should" indicate both the energy charge and the demand charge as separate components as this is useful information. It may bias the energy charge by some demand factor which is less useful.
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Don Kelly snipped-for-privacy@shawcross.ca
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But the standard meter doesn't measure KVA. It measures kWhr directly.

Yes. The meter is pf sensitive so it only responds to 'real' power (kW) and because it uses a set of gearing to move the dials, it also integrates the power over time to give you kilowatt-hours.
daestrom P.S. Of course many newer meters are electronic now instead of electro-mechanical. But the measurements are the same.
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Wrong assumption. Residential meters measure kWh. PF is built into the measurement.
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