What is the difference between residual current transformer and zero sequence current transformer?

Update:12-08-2021

Residual current transformer: The residual current transformer is dedicated to the collection of residual current, and can be used in conjunction with electrical fire monitoring devices, motor protection devices and residual current relays. The product can output 0~5(2)mA or 0~1V for the second time. There are round hole type and square hole type for users to choose according to their needs. It can continuously monitor the leakage current of the power distribution system, and realize the monitoring and control of electrical equipment at the same time, providing solutions for leakage monitoring and preventing electrical fires.
Zero-sequence current transformer: Mini Current Transformer It is suitable for indoor, rated frequency 50Hz or 60Hz, rated voltage 35kV and below small ground current system for three-phase cable grounding protection, and can also be used with relays. When the power system generates zero-sequence grounding current, it is used in conjunction with the relay protection device or signal to make the device components operate to achieve protection or monitoring.

Residual current current transformer: building power system, AC medium and low voltage power distribution system, hospital power distribution system, commercial, industrial power system, highway tunnel power distribution system, intelligent building power distribution system, electrical equipment.
Zero-sequence current transformer: used for power protection equipment such as: small current grounding line selection device, microcomputer harmonic elimination device, etc.