Current transformer installation precautions

The polarity of the current transformer cannot be reversed. The phase sequence and phase should meet the requirements of the design and regulation. For the transformer connection for differential protection, the current phasor diagram of the two arms must be measured before putting into operation to verify the correctness of the wiring;
2, according to the construction of the figure, the wiring is correct, the number marking on both ends of the wire should be clear, the label range meets the requirements of the regulations;
3. The secondary circuit conductor or cable shall be copper wire. The cross section of the current transformer circuit conductor shall not be less than 2.5mm2, and the cross section of the voltage transformer circuit conductor shall 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 line between the voltage loop and the current loop;
5. The arrangement of the secondary circuit conductors should be neat and tidy. The connecting screws of the wires and the electrical components and the terminal blocks must be free from loose connection. The distance between the wires and the card points should meet the requirements of the regulations;
6. The current and voltage circuits should be grounded at the point of the secondary side of the transformer. The voltage circuit should be protected by a fuse;
7. The first terminal block of the current transformer outlet should use a dedicated current terminal. The secondary winding not used by the current transformer should be short-circuited and grounded at the terminal block;
8. There should be no joints in the secondary circuit wires in the disk and cabinet. There should be no joints between the control cables or wires. If there is a joint, the terminal box of the long terminal should be used for the transition connection.