Working principle of zero sequence current transformer
Jan 01, 2024| The basic principle of zero sequence current protection is based on Kirchhoff's current law:
1. The algebraic sum of the complex currents flowing into any node in the circuit is equal to zero. When the lines and electrical equipment are normal, the vector sum of the currents in each phase is equal to zero. Therefore, the secondary winding of the Zero Sequence Current Transformer has no signal output and the actuator does not operate.
2. When a ground fault occurs, the vector sum of the currents in each phase is not zero. The fault current generates magnetic flux in the ring core of the zero sequence current transformer. The induced voltage on the secondary side of the Zero Sequence Current Transformer causes the actuator to operate. Drive the tripping device and switch the power supply network to achieve the purpose of ground fault protection.