Power Factor Correction and power saving for home use? Dirty power & smart meters 7

[1Slick]

This IEEE article explains that PFC helps smart meters read correctly... otherwise they can overcharge you for power by up to 582%:

https://www.utwente.nl/en/news/2017...77t7UI_aem_k9r09uVSnRF4RH-OOvfz5Q#582-percent

This is in response to an old post on the benefits of PFC for home use:
Nobody ever tested smart meters with dirty/noisy power.

Assuming that this is still of interest to some in this forum?
...possibly some of the original posters are still around?

 

[waross]

Thanks for the tutorial.
I have been doing power factor correction for about 50 years.
I was doing power factor correction successfully for years before power factor correction panels were available.
50 years ago, power factor correction was an art.
You obviously don't know the difference between Displacement Power Factor and Distortion power factor.
Metering errors due to fast rise transients are a third issue.
To correct displacement power factor from 80% to 100% the capacitor current needs to be 60% of the line current.
That is a lot of capacitors and a lot of money, but yes, the payback is very quick.
But fast rise transients?
There may be very little actual energy in a fast transient. It takes a very relatively small capacitor to trim the peak.
And a capacitor is not the only remedy. Some snubbers or surge suppressors will also kill the transients.

Many PFC users claim that the savings are ~1/3 of the power bill.
Given the potential metering error that claim sounds reasonable.

You really don't get it.
Yes, I have seen displacement power factor as low as 10% with a penalty of 80% of the bill.
that is DISPLACEMENT POWER FACTOR. DISPLACEMENT POWER FACTOR IS NOT METERING ERROR.

Transients shorter than the sample rate? These may causing metering errors.
When a transient is shorter than the sample rate it may be used as the value for the entire sample period.
So the meter records Too much voltage times the current times too much time.
That is not power factor.
Reading one paper that mentions power factor does not make you a power factor expert and you are not.

If you need multiple data points,

I have (more than once) used two years of historical data to plan power factor correction.
I have (more than once) obtained and used complete data, voltage per phase, current per phase, real power per phase, reactive power per phase. KWHr per phase KVARHr per phase. Recorded at 15 minute intervals over one or two or more months to solve customer metering concerns.
I was located in Western Canada when I got a phone call from Honduras.
A small utility paid my fair and expenses to fly to Honduras to solve some metering errors.
There was over %100,000 US dollars involved. The board of directors of the utility accepted my findings and refunded over $100,000 to a large customer.

Many PFC users claim that the savings are ~1/3 of the power bill.

If you want to throw anecdotes around, I have hours of metering anecdotes and power factor correction anecdotes, real first hand experience, not "users report".
Well schools over and I'm tired of teaching.
Time for the summer break.

--------------------
Ohm's law
Not just a good idea;
It's the LAW!

 

[bacon4life]

The methods of the article seem strange. Typically in my region of the USA we specify residential meters to be actuate to 0.2%, and yet the authors found a 3% difference between meters in their baseline resistive load test. Since the the authors could not reproduce baseline testing, the rest of the claims seem questionable.

Another questionable assumption is that the authors assume an induction disk meter is perfectly accurate as a reference meter. Induction disc meter tend to run slow in the presence of harmonic distortion.

Getting back to the original question-installing PFC can may harmonic distortion worse or better depending on the exact situation. Adding PFC is definitely not a first approach to address an inaccurate meter.

 

[1Slick]

Waross... we appear to be in agreement.

Displacement Power Factor v's Distortion Power Factor:

https://en.wikipedia.org/wiki/Power...wer factor is a,power transferred to the load

"Distortion power factor is a measure of how much the harmonic distortion of a load current decreases the average power transferred to the load."

"The distortion power factor is the distortion component associated with the harmonic voltages and currents present in the system."

"In linear circuits having only sinusoidal currents and voltages of one frequency, the power factor arises only from the difference in phase between the current and voltage. This is displacement power factor."

"Displacement Power Factor is not a metering error"

Yep... but PFC also cleans up the high frequency harmonics that cause the metering error.

Bacon4Life is also right.
PFC is probably not the best approach to the problem.
We conceded that in an earlier post and discussed a few alternative approaches.



Born under a wondering star

 

[LionelHutz]

This topic is familiar, based on work Gunner was doing maybe?

 

[waross]

Yes Lionel.
I was remembering some work Gunner was doing on this issue.
A true electrical Genius.
Gunnar's last login was on Friday, January 31, 2020. RIP
Did you know that in the motors forum Gunnar is still in 4th place in the all time MVP list?

Back to the current issue.
Displacement Power Factor Correction. This has probably been around for 100 years or so.
Distortion Power Factor mitigation. This is more recent. As more non-linear equipment came into use, mitigation of distortion power factor became more important.

Short transients and sample rate; This may be the present issue. This is a true error and not any type of power factor.
As I recall, Gunnar was working on this.

Is addressing this issue with PFC a good idea?
Maybe an illustration will help visualize my point.

I had a 300kg item that I regularly moved between locations.
The manufacturer of my vehicle listed the luggage capacity as 250 kg.

so I traded this:

for this

It may be a little overkill, but it gets the job done.

--------------------
Ohm's law
Not just a good idea;
It's the LAW!

 

[stevenal]

Skip the capacitors and get a better meter.[URL unfurl="true"]https://selinc.com/api/download/123140/?lang=en[/url]

 

[waross]

Thank you for posting that Steven. lps

--------------------
Ohm's law
Not just a good idea;
It's the LAW!