Is there any way to make zero crossing detection in 3 phase without using reference of neutral

 

Yes, sort of. There are three possible pairs of measurement points between the three phases. Sense the phase difference between these three pairs of measurement points to obtain the relative phases.

The illustration below shows the three measurement pairs.

 

Yes, but it is not easy. If you are asking about detecting the zero crossings of the three AC sinewaves in a delta-connected power system, you can do this by taking the long-term average of each sinewave (which is zero for an undistorted sine) and holding that potential as the reference for a comparator looking at the instantaneous value of the sine.

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