elektromery

[gatilo]

 7.4.2017, 21:50:36

Protoze ony "nepresnosti", nejsou ve prospech zakaznika !

S pozdravem Pavel
  mailto:gatilo + zavinac + centrum.cz

--
Michal Gregor napsal:

> 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.
>>
>>
>>
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