elektromery

[Pavel Hudecek]

Nepřekvapilo by mě, kdyby měly se zubatou sinusovkou taky problém, jen 
opačný:-)

Jinak ty elektronické mají jasné výhody ohledně vyúčtování:
- odečet bez ručního psaní: rychlé-levné a bez chyb
- elektroměr si pamatuje kolik náleží do kterého roku, takže když k odečtu 
dojde třeba 73 dní po změně ceny 1.1., lze to vyúčtovat korektně (alespoň 
tak nějak si to představuju při čtení mého vyúčtování)
- více sazeb neznamená dražší elektroměr

PH

-----Původní zpráva----- 
From: Michal Gregor
Tak proc se vlastne nepouzivaji klasicke elektromery?

Dne 6.4.2017 v 23:04 David Obdrzalek napsal(a):
> 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.