I don't found any link in your post.....Also I had did some search on forum but could not found any thing useful in that for the point that I am looking for.....Can you please share the link that you are intended to be.....
I was referring to "Similar Threads" on the bottom of the page. E.g. the first thread "how to detect phase unbalance" is discussing different options for 3-phase supply monitoring. And there are surely more, because this is a serial topic at edaboard.
In my view, it's necessary to clarify the specification in a first step. If presence of a true three-phase voltage system is required, you need to measure the interphase voltage. Having all three interphase voltage magnitudes around the nominal value also verifies, that they have 120° phase shift. Voltage to neutral check may or may not be required, also phase sequence (rotation direction) test.