[SOLVED] voltage and current measurement using atmega controller

i want to measure voltage and current of three phase supply need help . i dont know from where should i start ??

C dividers are safer at high voltage and lossless.
then decide if delta or Y
I sensors may be expensive CT or cheap but custom Hall sensors

then scale to your ADC range , add filters and decide if you want Vavg or V pk or true rms and convert accordingly

Decide on range, accuracy, and metrics 1st
eg. mean, std dev, peak , transient pk, V-sec of surge impulse. brown-out durations, interruption interval, imbalance etc , p.f.

For protection use series R and gas tube, TVS , spark plug etc. and choose R to limit below holding current of arc.

then filter and use twisted pair shielded or 50 Ohm coax with suitable drivers.

For bonus points , include a Partial Discharge V-s and pico Coulomb, peak detector, a common fault in power equipment used for Condition Monitoring and maintenance.

i didn't you completely ?
capacitor divider we can use for voltage measurement and what about current ?
plz post it in detail
thank for help

Pass the current through a known value of resistor with one end connected to the ground and measure the voltage across resistor by using the ohms law find out the current

its three phase supply so first i have to step down the voltage to give micro controller so how i can ? after that i can calculate current

Ohms Law on current shunt using <100mV drop for typical Low voltage app. Then Hall sensor for Proximity current. With load R
Or CT with rated burden R to match requirements.

CT means Current transformer with 1 turn primary to N secondary