voltage – How can I get a clear waveform of current and volatge of a micro grid to feed into a Arduino

With Arduino controller …

You need take “equally” time spaced (uses Interrupt Timer Task), and apply Fourier formulas.
(@50 Hz, timer every 2 or 1ms, 11 or 21 points, max 8 channels, voltages and currents)

Note that as “acquisition” takes some time (some 100 us) on Arduino, you need “software correcting” time delay (and so “phase”) between samples.

Zero crossing point is “not” needed, you need only two “software” references channels.

Note also that this method should not be “real time” task because of “calculus time” and should used only in “steady” measurements.