What are the connection modes of current transformer?

1. Single phase wiring

In this connection mode, the current flowing through the current coil reflects the current in the corresponding phase of the secondary circuit. Three-phase circuit usually used for load balancing, such as low-voltage power line, is used to measure current, electric energy or connect load protection devices.

2. Two-phase V connection

This connection is also called two-phase incomplete star connection. It is called two-phase double relay wiring in relay protection device. In three-phase three-wire circuit with ungrounded neutral point, it is widely used for measuring three-phase current and electric energy and for overcurrent relay protection. The current on two V-connected public lines reflects the phase current of the phase not connected with the current transformer.

3. Two-phase current difference wiring

In relay protection devices, this kind of wiring is also called two-phase relay wiring. This connection mode is suitable for overcurrent relay protection in three-phase three-wire circuit with ungrounded neutral point. In this connection mode, the current on the secondary side of the current transformer is 1.73 times the phase current (root number three, note: it may not be shown in front). ?

4. Three-phase star connection?

The three current coils of this connection just reflect the current of each phase. Widely used in I-phase four-wire system with unbalanced load, it can also be used in three-phase three-wire system with unbalanced load, and is used for measuring three-phase current and electric energy and overcurrent relay protection.