Why the measured output active power of generator is different using two different methods?

I am using synchronous generator in Simscape. when I measure the output active power using output voltage and current and Simpower active power block it is different with the active power shown by generator using its per unit vale port on the block (See figures). What is the reason for this difference?

Answer 1

[Sabin]

The problem here is that the power measurement is done through a three-phase phasor block that would expect phasor inputs. However, the value on the per unit port is instantaneous and the simulation is probably time simulation. Comparing the instantaneous power should give same (correct) results.