How to Install a current transformer?

How to Install a current transformer?

 The secondary circuit conductors or cables should all be make of copper wires. The cross-section of the current transformer circuit conductor should not be less than 2.5mm2, and the cross-section of the voltage transformer circuit conductor should not be less than 1.5mm2.

The first terminal block at the current transformer outlet should use a dedicate current terminal, and the unused secondary winding of the current transformer should be short-circuit and ground at the terminal board.

There should be no joints in the secondary circuit wires in the panels and cabinets, and there should be no joints in the middle of the control cables or wires. If joints are necessary, a transition connection with a longer terminal box should be use.

The polarity of the current transformer cannot be reverse, and the phase sequence and phase difference should comply with the design and regulations. For the transformer wiring for differential protection, the current phasor diagram of both arms must be measured before it is put into operation to verify the correctness of the wiring.

The secondary circuit wires should be arrange neatly and aesthetically. Additionally, the connecting screws between the wires and electrical components, as well as terminal blocks, must not be loose. Moreover, the distance between the wire binding points should comply with the requirements specified in the regulations.

The insulation of the secondary circuit to the ground should be good, and there should be no mixing of wires between the voltage circuit and the current circuit.

Both the current and voltage circuits should ground at one point at the secondary side outlet of the transformer.