# 3phase neutral fail detection

#### Chayan Roy

Joined Jul 16, 2016
2
Hello Everyone,
This is my first post in this forum. So, pardon me if I make any mistake in writing this post.
So, now the question : Actually I am making a three phase protection unit.Where I need to detect missing neutral or neutral fail. But I don't understand how to do that. I am using a microcontroller to do that. I am measuring voltages of each phase using adc of microcontroller..taking neutral asa reference which is also tied to the digital ground of MCU. Now my question is what should I do to detect missing neutral. I can't use any external circuitry for that,I have to do it in MCU. I also can't use earth point. Kindly give me an idea about possible solution. Thanks.

Joined Jul 18, 2013
19,466
You are already measuring each phase with neutral as a reference, so if the neutral is open you would have no phase measurement, as the reference is lost?
Max.