How to measure electric power?

Thread Starter

ArFa

Joined Apr 24, 2011
9
Hi all,
I want to measure output voltage, output current and output power of a 3-phase power generator, and send those data to MCU, how can I do that ?
 

#12

Joined Nov 30, 2010
18,076
3 current transformers, 3 voltage transformers, 6 rectifiers, 6 resistors, and 6 capacitors. These will give you a DC voltage proportional to each current and each voltage.
 

t_n_k

Joined Mar 6, 2009
5,448
3 current transformers, 3 voltage transformers, 6 rectifiers, 6 resistors, and 6 capacitors. These will give you a DC voltage proportional to each current and each voltage.
That setup won't give you the means of finding the real power - only the apparent power.
 

crutschow

Joined Mar 14, 2008
23,348
If you need real power then Analog Devices and others have chips that generate an indication of real power from the isolated current and voltage sensors that you would need to add in each phase.
 

WBahn

Joined Mar 31, 2012
24,693
Does the generator have a fourth neutral wire that potentially carries current? If not, then you only need to sense phase current in two wires and the voltage between those two wires and the third. That will let you compute real power very easily and you can get apparent power and power factor without much trouble, either.

If you are willing to assume that the generator is adequately maintaining the phase voltages and phase relationships, then you can get by with a single voltage measurement to establish your phase reference and just infer the other one.

If you have a current-carrying neutral, then you need to measure the currents in all three phase lines and the voltages between each of them and the neutral.
 
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