Does an analogue kWh meter over charge for harmonic distortions?

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SUMMARY

The discussion centers on whether analogue kWh meters overcharge due to harmonic distortions in electrical circuits. A test involving a low power factor motor and various meters revealed discrepancies in readings, suggesting that harmonic currents may influence charges. The use of power savers, such as the "Power Saver 1200" and products from "Continental Power Corp," indicates potential savings by addressing harmonics and power factor correction. Ultimately, the conversation highlights the complexity of power factor billing and the role of reactive loads in electricity consumption.

PREREQUISITES
  • Understanding of harmonic distortion in electrical systems
  • Knowledge of power factor and its impact on electricity billing
  • Familiarity with analogue and digital kWh meters
  • Basic concepts of RLC circuits and power factor correction devices
NEXT STEPS
  • Research the effects of harmonic distortion on energy billing
  • Learn about the operation and effectiveness of power factor correction devices
  • Investigate the differences between analogue and digital kWh meters
  • Explore the principles of RLC circuits and their application in power systems
USEFUL FOR

Electrical engineers, energy efficiency consultants, and anyone interested in optimizing power consumption and understanding the implications of harmonic distortion on electricity billing.

kouty
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If a analogue kWh meter is made of coil windings and coil windings dissipate harmonics currents then is it possible that we are being charged more kWh if we create harmonics on our circuit? I did a test once with a low power factor motor and 200 meters of extension cable. The power was coming from the plug socket (240 volt 10 amp single phase) through a clipsal distal meter, then through a "Email Limited" brand kWh meter then through another digital meter then through a fuse box that had static power power factor correction device attached. The motor was the last on the circuit. When the motor was running without load so with a low power factor (about 0.46) the two digital meters we're giving two different readings. The one outside the circuit after the kWh meter was always showing a higher reading. When I turned on the power saver the kWh being charged and also displayed on the outside meter dropped by 16%.

We are all told that power savers don't work and that residential customers are not billed for power factor or the kVAr leaving upstream.

So what's causing the saving?

After a lot of research I am coming to the understanding that it may have been the harmonic distortions on the line that are being recycled as it we're by the power saver.

The problem with power savers like the one I used in this experiment and the "power saver 1200" and "KVAR" in the USA is that they don't seem to drop everyone's bill.

Company's like the "Continental Power Corp" that have been selling there "Powerworx" product for 15 years claim a minimum of a 10% saving. Does there power saver work because it removes harmonics as well as help to correct the power factor and therefore amp draw as well as surge protection to remove voltage peaks and spikes.

If anyone could shed some light as to why I got the different readings before and after the meter I would really appreciate it.

Does an analogue kWh meter over charge for harmonic distortions?
 
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Power factor is a tricky business; you can't just toss a static device into the equation and expect it to fix everything. In my understanding, industry is billed by power companies for having a low power factor, in addition to being charged for the total power they consume, which is actual power divide by power factor (I think). When they say you aren't billed for power factor, I think they're just saying that they don't charge extra for having a high reactive load on the circuit; you're probably still being charged for the total power rather than actual power.

I think those "static power factor correction devices" are just fancy names for a big capacitor. You can do some research into http://en.wikipedia.org/wiki/RLC_circuit" , but basically, power-factor nears one as capacitance and inductance come into balance. Electric motors have terrible power factors because they are designed to create magnetic fields, and thus have high inductance. A capacitor is needed to balance this. On the other hand it is possible to over correct. Too much capacitance and your power factor goes back up again. The minimum power factor, and thus minimum bill, occurs when the current and voltage are in phase; once this happens you're only being billed for the resistive load, and further improvement is not possible without decreasing the resistive load on the circuit.
 
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