Different Reactive Power

[Veronika.Salinas]

Hi everyone! 

We have a customer who has a Sentron PAC 4200 meter (Siemens) and wants to replace it with a ION7400. The customer monitors the energy system on a SCADA using modbus registers and I'm having difficulty finding some parameters on the ION7400. In order to replace the siemens meter, it is necessary to find the same parameters in the ION7400

These are the definitions I found of a Siemens file:

Q1 = Displacement reactive power over the fundamental U1
Qtot = Total reactive power

Qn = Shift reactive power over fundamental U1 + harmonics Un. 

What I found on the ION7400 modbus map is:

Q1= Fundamental Reactive Power Total

Qtot = Reactive Power Total

I couldn't find any parameter to replace Qn. Do you know if this parameter exists in ION7400?

Thank you!

[Charles_Murison · Accepted solution]

Hello @Veronika.Salinas ,

Looking at the PSC4200 documents I did see 

If my Math is correct
Qn = (S^2+Q1^2 -P^2 -Qt^2)^0.5
I do not know if this is something that is in the default Modbus map however since this is ION, it could be possible to use a framework to calculate this value and then expose to modbus via the modbus slave module.

Regards,

Charles