Zero Sequence Current Transformer protects against failure

Zero Sequence Current Transformer is a current transformer specially used to transform zero sequence current. When the zero-sequence grounding current is generated in the power system, it is used in conjunction with the relay protection device or signal to make the device components move and realize protection or monitoring. Due to the rapid development of power system, various operation modes, various types of protection devices emerge in an endless stream, and a large number of protection devices are imported, so there are many types of Zero Sequence Current Transformer required.

The basic principle of Zero Sequence Current Transformer protection 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, that is, ∑I=0, which uses the zero-sequence CT as the sampling element. When the electrical equipment is normal, the vector sum of the currents of each phase is equal to zero (the unbalanced current is assumed not to be considered for the zero-sequence current protection). Balance current) The actuator does not act. When the ground fault occurs, the vector sum of the currents of each phase is not zero, the fault current generates magnetic flux in the ring core of the zero-sequence CT, and the induced voltage on the secondary side of the zero-sequence CT makes the The components act, drive the tripping device, switch the power supply network, and achieve the purpose of ground fault protection.