I would like to detect if a current flows in a 3-phase industrial environment where currents can go up to 120A. Anyway, for me is only important information current is flowing/current is not flowing. The threshold should be somewhere about 0.5A - 1A. I excluded shunt and current transformer solutions from consideration because I cant put shunt anuwhere (but I also think it is not quite applicable for such high current environments) and the later seems to be more expensive than solutions with Hall-effect sensor which I would like to consider here. In this question I would like to consult you about the principles in order to choose the one that fits the best my application.
Is there a Hall-effect sensor which is able to provide a digital output based on the absolute value of the magnetic field? I checked various types of Hall-effect sensors, bipolar, unipolar and omnipolar. The closest to what I want is unipolar but none of unipolar sensors can actually treat south and north poles in the same way. By this I mean, that threshold should be for +- x T. Using such an element I believe I would minimize my BOM.
Since all three phases are in vicinity of each other, how sensitive might be using Hall sensors in such environments in terms of flux cancelations?
Would it be possible to implement this without a ferrite ring for concentrating magnetic flux? My calculations give in the worst case, 3mm away from the conductor about 0.5G (2/3e-4 T).
Is there any other interesting way of doing this that I missed completely?