EM24 ethernet, grid power vs grid current discrepancy

[Radunre]

On a 3 phase system with EM24 ethernet installed as Grid meter I get attached graphs for power and current.

The power graph is showing the right flow and compensation but the current one is strange and only showing positive values.

Is there an explanation or is a bug ?

[WZkevin (Vennens Kevin)]

This seems normal to me.

The power indicates the direction of the flow, either positive or negative. The current measurement only shows the amperage and does not indicate the direction of the current.

[Radunre]

Considering that other system components like battery or inverter are declaring the current and power with direction depending polarity, solely the grid meter doing only positive current seems really odd.

[jeroen]

@Radunre

Is there an explanation or is a bug ?

There is an explanation. What is being shown (in the graph) is the root mean square value (RMS) of the current. See https://www.electronics-tutorials.ws/accircuits/rms-voltage.html for more details e.g. Since it is the root of the average of squares it can’t be negative in the real world. If you would instead average it over time e.g., you would end up with a zero current, since it is AC.

The UX showing negative values for the RMS AC current, while technically incorrect, is far more intuitive for most users. It just steals the sign from the power.

[Radunre]

Thank you for your time and explanation.