What should be paid attention to when installing current transformers

1. The polarity of the current transformer cannot be reversed. The phase sequence and phase should meet the design and regulation requirements. For the transformer connection of differential protection, the current phasor diagram of the two arms must be measured before putting into operation to verify whether the wiring is correct.

2. According to the structure of the diagram, the wiring is correct, the number marks at both ends of the wire should be clear, and the label range meets the specified requirements;

3. Secondary circuit conductors or cables shall be copper wires. The cross-section of the current transformer circuit conductor should not be less than 2.5mm2, and the cross-section of the transformer circuit conductor should not be less than 1.5mm2;

4. The secondary circuit should be well insulated from the ground, and there should be no mixed line between the voltage loop and the current loop;

5. The layout of the secondary circuit wires should be neat. Wires and electrical components and connecting screws of terminal blocks must have no loose connections. The distance between the wire and the card point should meet the specified requirements;

6. The current and voltage circuits should be grounded on the secondary side of the transformer. Voltage circuits should be protected by fuses;

7. The first junction box of the current transformer socket should use a dedicated current terminal. The unused secondary winding of the current transformer should be short-circuited and grounded at the terminal;