Current Transformer Installation Precautions

1. The polarity of the current transformer cannot be reversed. The phase sequence and phase should meet the requirements of the design and regulations. For the connection of the transformer used for differential protection, the current phasor diagram of the two arms must be measured before it is put into operation to check the correct wiring. sex;

2. The construction shall be carried out according to the drawings, the wiring shall be correct, the numbering marks at both ends of the wires shall be clear, and the range of the numbers shall meet the requirements of the regulations;

3. Copper wires should be used for secondary circuit conductors or cables. The cross-section of current transformer circuit conductors should not be less than 2.5mm2, and the voltage transformer circuit conductor cross-section should not be less than 1.5mm2;

4. The insulation of the secondary circuit to the ground should be good, and there should be no mixed lines between the voltage circuit and the current circuit;

5. The arrangement of the secondary circuit wires should be neat and beautiful, the connection screws between the wires and the electrical components and the terminal block must be free of virtual looseness, and the distance between the wire binding and the clamping point should meet the requirements of the regulations;

6. The current and voltage loops should be grounded at one point at the outlet of the secondary side of the transformer. The voltage loop should be protected by fuses;

7. The first terminal block at the outlet of the current transformer should use a dedicated current terminal, and the secondary winding not used by the current transformer should be short-circuited and grounded at the terminal board;

8. There should be no joints for the secondary circuit wires in the panel and cabinet, and there should be no joints in the middle of the control cables or wires.