Utility Billing KWH/ Measures in KVA but bills in kWh

---------------------------- "ItsASecretDummy" wrote in message news: snipped-for-privacy@4ax.com...

----------------------- Industrial demand metering measures peak KVA demand -not power factor. Energy metering inherently measure the kWh used without the need for a power factor "correction". 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.

Please, when you have the knowledge that Daestrom has, then you can make sensible comments without the childish invective. Otherwise go and play with Roy.

By the way, top posting is far less offensive than your abusive approach.

Why do you think power companies hang capacitor banks on their delivery systems?

Don't be an idiot. You joined that bash session long before I did. Hell, you piloted the whole damned hayride for a while as I see it.

Bullshit.

| 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.

| Why do you think power companies hang capacitor banks on their delivery | systems?

To compensate for the inductance in long distribution lines?

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)

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

And that is why large industrial customer revenue metering includes RkVA meters as well. So the utility can be paid for the equipment they maintain that is needed to support the reactive load the customer is drawingl. But if the customer was *required* to correct their own pf, there wouldn't be any RkVA load now, would there 'Dummy'?? Must be the utility installs those RkVA meters just for fun.

The NY tariff I posted a link to earlier (which apparently you haven't bothered to read) also points out that the RkVA demand charge is determined when the kW demand of the customer is more than 500 kW. But I guess all that 'reactive demand' charges and stuff is just put there for fun since you claim all customers are *required* to correct their pf.

Read the tariffs and stop being such a stubborn, vulgar jerk.

daestrom

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It's not to correct the customer's power factor-which can only be done effectively at the customer's location. A capacitor on the line will not provide any pf correction benefits "downstream"

They are often used on longer feeders (even where the loads are mainly residential and average 0.8pf or better) to improve the voltage profile along the line under normal loading. Certainly a customer's low pf will worsen the profile .

I wrote this before seeing Phil's and Daestroms comments- guess what- they are right. --

Don Kelly snipped-for-privacy@shawcross.ca remove the X to answer

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

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.

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.

Idiot. Not all loads can be corrected. That's where you forgot reality.

It is not to correct their power factor. It is to correct how their meters read their true usage.

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

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

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

---------------------------- "ItsASecretDummy" wrote in message news: snipped-for-privacy@4ax.com...

----------- The governor on a generator has nothing at all to do with MVAR loading. It is a speed/frequency control device affecting the mechanical prime mover which doesn't even "see" MVAR loads. Please not that Daestrom has power utility experience and knowledge- so why try this nonsense on him?

Regarding other messages:

Your customers want control of harmonics (which, as a side issue do affect power factor) rather than power factor per se. because total harmonic distortion (THD) is what utilities want limited. Bringing the pf (defined on the basis of VA/W) to near unity implies appreciable reduction of these harmonics through filtering, etc. In other words, for a sinusoidal voltage applied, a sinusoidal current is wanted. You likely do not have appreciable phase differences (phase difference is meaningless when comparing signals of two different frequencies) but a low pf due to harmonic currents increasing the total rms current. As Daestrom indicated, this affects other customers. In general customers are not required to correct low power factor but as this can affect their KVA demand, there is a financial incentive to do so.

In the case of your power supplies, a high harmonic content increases the rms current for a given rms voltage but the voltage may not have any appreciable distortion- resulting in low "power factor" but low vars.

As for capacitors on the distribution lines- the reasons were given to you. They cannot correct the metering at the customers location.

There are non-harmonic producing loads which have a low power factor and these will not significantly affect the accuracy of the KWh meter. Measuring KVA or KVAR works in this case but, since a typical VAR meter is nothing more than a wattmeter with the voltage phase shifted by 90 degrees - how do you know if it is accurate? In view of some of the factors mentioned above, it may not be at all effective in dealing with harmonic loads.

So far, you have made some questionable statements which indicate that you are stepping beyond your knowledge base.

Don Kelly snipped-for-privacy@shawcross.ca remove the X to answer