Watt Hour Meter Power Factor Testing

Your PF is .98? That's not abysmal...that's pretty damn fine per industry norms.

You aren't going to get a PF anything greater than 1.0 (not your 100.5%). That would be over-unity, and is not achievable in this universe.

Your watt-hour meter will display the actual load...not what the generator is capable of putting out. If you have a 4 kW gennie and it is running at "full load", then your meter would likely show a watt-hour usage in line with that figure. Good luck with that.

I guess my question wasn't clear. When I am testing the meter at unity it reads 100%. When I inject a signal in which the current is at a different phase angle than the voltage, the meter will only register 98.5% of what I gave it. Therefore the meter is being affected and then is somehow taking the reactive component into account. Obviously, I know this is not supposed to happen and on any other meter I could adjust for this by turning the "power factor" screws on the meter. But this meter doesn't have any such screws and therefore there is no way to adjust it out.

James,

My apologies and thanks for the clarification. So you have a meter that isn't behaving properly and may not be from one of your usual vendors. If it doesn't have the adjusting screw it may not be a billing or revenue meter, just one for monitoring the energy for informational purposes. Those don't need to be quite as accurate because money isn't at stake, kind of like the difference between the CT accuracy class for metering vs measuring. Maybe a call to the manufacturer will provide more details.

Alan

James,

Watt-hour meter only register active(watt) power consumed over a time i.e.energy. Most likely you are changing the power factor angle in your test set up by a phase shifter. While doing so please check up whether input voltage in the meter is changed due some faults/loose connections etc. in your test set up,Regards,

Manindra.

not using a phase shifter but I am familiar with those. I am using a test equipment that allows me to put out exact poly phase power at specific phase angles. Input voltage and current are solid and do not change.

Read the nameplate of KWH meter on which PF will be mentioned as between 0.8 to 1. if you use this meter for a load with low pf(0.6 without PFC capacitors) the reading shown won't be accurate. To make sure go through specifications of KWh meter.

Pnaban,

"...the reading shown won't be accurate..." What is the justification for this statement? A kW is a kW independent of the load power factor. As James noted he expected the reading to be unchanged as he injected more reactive current into his meter. A properly designed and calibrated KW or KWhr meter only measures the effect of real power, Watts, nothing else.

There was a mistake,it should read kVA(Max demand) not kWh meter.

At what phase angle are you getting the allegedly "abysmal 98.5%" reading? Why are you sure that is not what you should get?

98.5% of energy delivered is being seen by WHM instead of 100%. This occurs at 45 degree angle

Watt-hour meters don't measure reactive power. So don't worry about it.

you completely missed the point but thanks for your opinion