IAMMETER / APS INVERTER power measurement difference

Good morning,

I have a small production measurement problem....
I use a WEM3080T in "photovoltaic" mode.
as in the diagram below.

My concern is that I see a maximum power coming from the inverter of approximately 636W while at the same time the inverter indicates an output power of 730W!

see below :

and of the inverter 

The technical documentation of the inverter indicates 730VA maximum output.
Could you help me to solve this problem?

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"The technical documentation of the inverter indicates 730VA maximum output."

Active power =U*I*power factor.

And the power factor is less than 1

So the active power(w) must be less than the apparent power(U*I)

If the maximum output is 730VA, why it will output 760W ?

ok, i understood the difference between active power and apparent power.
However, this does not explain the big difference between the 2 values: 125W!
I think the inverter is given for 730W but it can develop slightly more ....


The accuracy of the energy meter is class 1,it means the maximum error will be within 1%.

Besides comparing the power reading, have you compared the hourly kWh?
What is the difference in the hourly kWh between the IAMMTER and your inverter`s monitoring system?


from inverter :

from meter : 

per hour :

for the day : 02/08/2023 :

meter : 2.79 Kwh

inverter : 3.20Kwh



This is my understanding

1 the document of the inverter shows its maximum power output is 730VA, but its output indicates 760W(the active power can not be larger than the apparent power).

So I think there must be one mistake, the parameter listed in a document or the measurement result.
In my opinion, I think the measurement result is wrong.

I was sure about the accuracy of our energy meter,if it is not damaged during shipment, the accuracy will be class 1(the maximum error is within 1%).

If you want to confirm whether the meter is damaged, you can judge it this way.


Or have you compared the grid consumption result with your electrical billing? if the grid consumption result is nearly the same as your electrical billing, you can also install phase A on the grid side(parallel with phase B) and check whether these two phases is nearly the same result.
This is to use the measurement result of one phase to demonstrate the accuracy of another phase.

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