elektromery

[David Obdrzalek]

Zajimave cteni o testovani elektromeru:
Static Energy Meter Errors Caused by Conducted Electromagnetic Interference
http://ieeexplore.ieee.org/document/7866234 (Abstrakt viz nize)
Holandani zjistili, ze moderni elektromer muze hodne prehanet, z testovanych jeden 
dal dokonce +582%, to bych teda nechtel platit ucet podle nej...

Verejne pristupny je bohuzel jen abstrakt, takze pro ty, kdo nemaji pristup k celemu 
clanku: vevnitr pisou, ze pokud je prubeh napeti pekna sinusovka, je to OK, ale kdyz 
je zubata, muze kvuli zpusobu mereni proudu elektromer namerit mnohem vic, nez je 
skutecnost. Pritom zubatou sinusovku presne okopirovali z realne moderni budovy. 
Merili, co zaznamenaji elektromery zatizene 30xCFL + 20xLED lampama. 
To o zubate sinusovce je z dizertace volne pristupne na http://doc.utwente.nl/88378/ 
zacatek na str. 55.

Report o vyzkumu zde:
https://www.bleepingcomputer.com/news/hardware/millions-of-smart-meters-may-over-infl
ate-readings-by-up-to-600-percent/

Lab tests carried out by Dutch scientists have shown that some of today's "smart" 
electrical meters may give out false readings that in some cases can be 582% higher 
than actual energy consumption.

Kmentar je i na Hackaday:
How to Trick Your Electrical Meter By Saving Power: 
http://hackaday.com/2017/04/04/how-to-trick-your-electrical-meter-by-saving-power/

Takze zlatej Krizik nebo ten Sodeco Geneve, co tu nedavno sel :-)

D.O.


Abstrakt clanku:

Static, or electronic, energy meters are replacing the conventional 
electromechanical meters. Consumers are sometimes complaining about higher energy 
readings and billing after the change to a static meter, but there is not a clear 
common or root cause at present. Electromagnetic interference has been observed 
between active infeed converters as used in photo-voltaic systems and static meters. 
Reducing the interference levels eliminated inaccurate reading in static meters. 
Several field investigations failed to identify a clear root cause of inaccurate 
readings of static energy meters. Experiments were performed in a controlled lab 
environment. Three-phase meters showed large deviations, even when supplied with an 
ideal sinusoidal voltage from a fourquadrant power amplifier. Large variations could 
be observed when non-linear, fast switching, loads were connected. A deviation of 
+276 % was measured with one static energy meter, +265% with a second and -46% with 
a third static energy meter. After dismantling it was revealed that the meters with 
the positive deviation used a Rogowski coil current sensor. The meter with a Hall 
effect-based current sensor gave the -46% deviation. The fourth meter, with a 
current transformer, resulted in -10% in one experiment and +8% in another 
experiment, where the deviations are with respect to a conventional 
electromechanical meter. Measurements were repeated with more meters and supplied 
from standard, low internal impedance, mains supply in the laboratory. Deviations of 
+475%, +566%, +569%, +581%, +582% and -31% and -32% were registered, with again the 
positive deviation for Rogowski coil current sensors and negative deviations for the 
Hall sensors.