"electronic energy meters give readings up to 582% higher than actual energy co" - Page 1
Forum section: electronics / general

author: 741
author_rank: Frequent Contributor
timestamp: March 02, 2020, 05:35:12 pm
content: Here is the linkhttps://www.utwente.nl/en/news/2017/3/313543/electronic-energy-meters-false-readings-almost-six-times-higher-than-actual-energy-consumption#explanation

author: coppice
author_rank: Super Contributor
timestamp: March 02, 2020, 06:18:09 pm
content: That report came out in 2017, and was discussed at the time. They didn't really give enough information to fully understand their results, and there seemed to be no follow up clarifications. The IEC standards for energy meters do not adequately define the required behaviour of a meter with a rich harmonic mix in either the voltage or the current waveform. Likewise, the typical qualification tests for type approval of energy meters to not extensively test these behaviours.

author: bdunham7
author_rank: Super Contributor
timestamp: March 02, 2020, 06:29:12 pm
content: It seems that they are (perhaps inadvertently--or perhaps not) charging you extra if you have a non-PFC load. That might be appropriate.

author: coppice
author_rank: Super Contributor
timestamp: March 02, 2020, 06:43:26 pm
content: Quote from: bdunham7 on March 02, 2020, 06:29:12 pmThe study says nothing about power factor. It refers to loads with a high harmonic content, although the power factor might also not be great.

author: chickadee
author_rank: Contributor
timestamp: March 03, 2020, 06:15:25 pm
content: Sounds like a bunch of people should measure their actual vs. billed consumption!

author: David Hess
author_rank: Super Contributor
timestamp: March 04, 2020, 12:05:04 am
content: Quote from: coppice on March 02, 2020, 06:43:26 pmHarmonic content contributes to power factor. The common E * I * Cos(angle) only applies to linear loads.

author: coppice
author_rank: Super Contributor
timestamp: March 04, 2020, 01:01:11 am
content: Quote from: David Hess on March 04, 2020, 12:05:04 amIf you have a pure voltage waveform, no amount of harmonic distortion in the current waveform contributes anything to the active power. Its only when both waveforms are distorted that the correlation between the harmonics in the two waveforms contributes to the active power. This is one reason what many energy meters for industrial consumers now measure fundamental active power as well as total active power, since if the utility provided a nice clean voltage sine wave the two power readings would be equal.Note that there several metrics termed power factor. Everyone agrees on what power factor means for pure sine waves. Most people agree that the correct way to measure power factor is based on an aggregate of the power factors of the individual harmonics. However, many measurements of power factor are simply based on the aggregate apparent and active powers, and some simple trigonometry that's only really meaningful for pure sine waves.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: March 04, 2020, 01:18:57 am
content: The trig process is calleddisplacement power factor, and AFAIK is, either the fundamental PF, or the PF due to phase shift (phase in terms of the overall waveforms, or individual harmonics?). I... don't remember reading an exact definition for it, but it's a measurement on most meters so should be easy to find.Tim