Houses Energy Meters Accuracy
Houses Energy Meters Accuracy
(OP)
I want to know if the changes in the net voltage affects the amount of energy the house meter reads.
When was the last time you drove down the highway without seeing a commercial truck hauling goods?
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Houses Energy Meters Accuracy
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RE: Houses Energy Meters Accuracy
For a resistance load such as incandescent lights, the energy used will be proportional to the square of the voltage. A 10% increase in the voltage will cause a 21% increase in energy. (1.1²-1)·100
For thermostatically controlled heating loads, the energy will not change because with higher voltage. Even though the energy will increase with the square of the voltage while the heating element is on, the heating element will not be on as long because it will get hotter.
Motor loads generally will use about the same energy independent of voltage.
RE: Houses Energy Meters Accuracy
RE: Houses Energy Meters Accuracy
RE: Houses Energy Meters Accuracy
RE: Houses Energy Meters Accuracy
Industrial meters use PT and CT, and this values are passed to the meter and then the energy is determined.
Power(W)= V x I x cos &
Energy(Wh) = V x I x cos & x h
The meter has to register V and I to determined the exact energy drew. And using only the current, like the old residential meter, it will create a wrong reading. I know that the voltage has to stay close to the nominal value (240/120 V), but if it change to 100 V some load will work with this value and will draw more current. The meter using only the current like parameter will register more energy.
RE: Houses Energy Meters Accuracy
RE: Houses Energy Meters Accuracy
RE: Houses Energy Meters Accuracy
Meter doesn't care what the voltage is within its operating
range. The power will still be metered correctly.
rodar
RE: Houses Energy Meters Accuracy
http://www.analog.com/UploadedFiles/Application_Notes/2...
(a larger pdf file)
for an application note:
A Tamper-Resistant Watt-Hour Energy Meter Based on the AD7751 and Two Current Sensors by Anthony Collins and William Koon
It states accuracy of kWhr meter.
RE: Houses Energy Meters Accuracy
Thank you for your answers.
RE: Houses Energy Meters Accuracy
http://www.geindustrial.com/products/brochures/GEA-1148...
kwH meters **always** use voltage and current, and have for about 100 years, so not sure where you're headed with this.
Even electro-mechanical meters are extremely accurate devices.
Any Electrical Engineers Handbook will have a useful section on watt-hour meters.