Principle of residual current transformer

Residual current transformer is often used in conjunction with residual current electrical fire monitoring detectors for the detection of leakage current (ie residual current). It is a special transformer that is composed of a coil and an iron core. The principle is based on Kirchhoff's current law: the algebraic sum of the complex current flowing into any node in the circuit is equal to zero. When the line and electrical equipment are normal, the vector sum of each phase current is equal to zero, and the secondary winding of the residual current transformer has no signal output; when a ground fault occurs, the vector sum of each phase current is not zero, and the fault current causes When the magnetic flux is generated in the toroidal core of the residual current current transformer, the secondary winding will send out a signal. When the electrical fire monitoring detector receives the signal, it will send out an alarm.