Displacement Power Factor (DPF) measurement model

This simulink model provides the DPF measurement as well as phase difference.

Two values need to be defined initially: f and Ts where f is the frequency of sinusoidal signals and Ts is the sampling time period.
In this simulation, f is chosen to be 60 Hz and Ts = 1e-6 seconds.
If the current lags the voltage, the phase difference will be negative.
if the current leads the voltage, the phase difference will be positive.