Smart Meters and power factor correction

[tttonyyy]

Someone here might know this - do Smart Meters correct for power factor?

For example, I have a microwave that (at standby) draws 163mA @ 240V which sounds like 39W (ouch - expensive way to run a front panel clock).  But the power factor is 0.02.

Will my snazzy EDMI ES-10B smart meter be billing me for 39W or 1W?

[jonpaul]

Utility billed energy is measured in kWh, the meters are quite précis.

The stand-by power of all connected devices will add up, and PF be ~ 0.5..07.

By national regulations electronic devices over a certain wattage must be PFC.

Check applicable regulations in your area, eg IEC in EU.

bon chance

j

[tttonyyy]

According to the datasheet here: https://www.edmi-meters.com/wordpress/wp-content/uploads/2018/05/ES-10B-Factsheet-English.pdf

Measured Values
• Active energy import (Wh)
• Reactive energy import (varh)

It sounds as though "old" induction-disc meters that only measure real power (that in phase with voltage) would not charge for reactive loading, but that may not be true of Smart Meters.

[jonpaul]

check out the smart meter spec sheet and metering regulations applicable in your area

All meters that affect the rates and electrical bill of utilities are tightly regulated

https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/381535/SMIP_E2E_SMETS2.pdf



Large industrial distribution ovrr 50...250 kva, have utiliy surcharge for excessive VARs, hence PFC capacitor  banks

j

[wraper]

Residential meters don't.

[tom66]

Residential meters don't.

They do or otherwise they'd bill you for kVAh.  UK domestic customers are only billed for kWh but to accurately measure kWh you need to know the power factor (or at least measure enough to calculate it)

My meter even shows you kVAh and kWh separately if you dig through the menus (UK SMETS2 domestic energy meter), though I'm only billed for kWh and you can get the in-home display to show kVAh.  It doesn't show the calculated power factor but I know the accuracy must be within +/-3% across the full dynamic range - I wouldn't be surprised if this is over e.g. 0.1PF to 1.0PF - and in the negative for solar/battery systems.  I would imagine to achieve this accuracy and linearity it must be sampling the current waveform at a reasonably high sample rate with a modest ADC - probably at least 10ksps at 16-bit or above.

[wraper]

Residential meters don't.

They do or otherwise they'd bill you for kVAh.  UK domestic customers are only billed for kWh but to accurately measure kWh you need to know the power factor (or at least measure enough to calculate it)

My meter even shows you kVAh and kWh separately if you dig through the menus (UK SMETS2 domestic energy meter), though I'm only billed for kWh and you can get the in-home display to show kVAh.  It doesn't show the calculated power factor but I know the accuracy must be within +/-3% across the full dynamic range - I wouldn't be surprised if this is over e.g. 0.1PF to 1.0PF - and in the negative for solar/battery systems.  I would imagine to achieve this accuracy and linearity it must be sampling the current waveform at a reasonably high sample rate with a modest ADC - probably at least 10ksps at 16-bit or above.

I meant they don't charge you for power factor. Industrial power meters do. I probably misunderstood the question.

[Benta]

As a domestic/residential consumer you'll only be billed for real power (kWh). I've never heard of exceptions anywhere in the world to this.
That being said, copper losses in your local installation (=after the meter) due to bad power factor will of course increase real power consumption a bit (perhaps 1...3%).

Large-scale consumers (office buildings, industry, super markets, shopping malls, server farms) is a different story. They pay for reactive power.

[nali]

To OP: That meter can report both real & reactive, import & export. Mind you what your energy supplier actually charges you for is up to them...

If you want to look at devices typically used, take a look here https://www.digikey.co.uk/short/0bjhfn8h

[Zero999]

Residential meters don't.

They do or otherwise they'd bill you for kVAh.  UK domestic customers are only billed for kWh but to accurately measure kWh you need to know the power factor (or at least measure enough to calculate it)

No you don't need to know the power factor to calculate kWh.

[tom66]

No you don't need to know the power factor to calculate kWh.

My point is that you need to measure both V and I continuously, rather than independently, and this is all the information you need to calculate W, VA and PF and numerous other terms.   Yes, you do not need to calculate PF to work out W, but you have gathered all of the information required and it's a pretty simple calculation from there on.

If you only want to measure VA you can do this by having independent TRMS volt/ammeters on each channel (but I don't think anyone is billed on only reactive power)

[Miyuki]

It is simple
Just look at your bill
If it is in kWh/MWh or in kVA/MVA.
They are different units for different things.

[thm_w]

It is simple
Just look at your bill
If it is in kWh/MWh or in kVA/MVA.
They are different units for different things.

Its not really that simple, I mean yes for OP we've established they only pay for real power.

But for industrial, at least here, you pay real power at the regular rate, then a fee on top of that for average power factor (NOT instantaneous), eg:
>90% power factor is 0% fee
<50% power factor is 80% fee

So you never get charged in VA.