What is the difference between a current transformer and a zero sequence current transformer? 
1. Current transformer is different from zero sequence current transformer. 
The zero sequence current transformer is used to detect the zero sequence current. 
In general, all three fire wires pass through the inner hole of the transformer to measure the vector sum of the three-phase current, that is, zero sequence current. 
2. The characteristics of zero-sequence current determine that under normal conditions, the primary current of zero-sequence current transformer is very small, but in abnormal cases, the zero-sequence current is also very large. 
3. Because the zero-sequence current transformer usually passes through three fire lines, the inner hole of the zero-sequence current transformer is larger at the same current. 
The inner hole aperture is an important index of zero sequence transformer. 
4. The level of Huai is lower. 
In daily life, we do not often see the current transformer, but it covers many places, its existence is indispensable. 
As a special transformer, the working principle of current transformer is similar to that of transformer. 
The difference is that in the core of the transformer, the alternating main flux is caused by the AC voltage and current increased at both ends of the winding. 
In the secondary winding of the current transformer, the alternating main flux inductance in the iron core should produce the corresponding secondary electromotive force and secondary current. 
Because the primary winding and the secondary winding system of the current transformer are in the same iron core, they are connected by the same alternating main magnetic flux, so the current and turn product of the primary winding and the secondary winding should be equal.