[SOLVED] voltage and current measurement using atmega controller

[tinkujangid]

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

 

[D.A.(Tony)Stewart]

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.

 

[tinkujangid]

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

 

[hobbyckts]

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

 

[tinkujangid]

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

 

[D.A.(Tony)Stewart]

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