Tips for installing cable termination

In the installation of power engineering, the cable termination kits and the joint kits are important power equipment components in the power transmission and transformation cable line. Its role is to disperse the electric field at the external shielding of the cable termination, maintain the cable from being broken down, and have internal and external insulation and waterproof effects. In the cable line, more than 60% of the incidents are caused by accessories, so the quality of the joint accessories is very important to the safety and reliability of the entire power transmission and transformation.

1. Connection of conductor

Conductor connection requires low resistance and meet the mechanical strength, the junction can not present sharp corners. Medium and low voltage cable conductor connection is commonly used crimping, crimping should be noted:

a. Select the appropriate electrical conductivity and mechanical strength of the conductor connection;

b. The cooperation gap between the inner diameter of the pressure receiver and the outer diameter of the wire core to be connected is 0.8 ~ 1.4mm;

c. The resistance value of the joint after crimping should not be greater than 1.2 times of the equal section conductor, and the tensile strength of the copper conductor joint is not less than 60N/mm2;

d. Before crimping, the outer surface of the conductor and the inner surface of the connection are coated with conductive adhesive, and the oxide film is damaged with a wire brush;

e. The sharp corners and rough edges on the wire core conductor should be polished and lubricated with file or sandpaper.

2. Internal semiconductor shielding processing

If the cable body has an inner shield layer, it is necessary to repeat the inner shield layer of the receiving conductor part in the manufacturing of the joint, and a part of the internal semiconductor shield of the cable should be set aside so that the inner shield of the connecting head at the junction can be connected to each other and ensure the continuity of the internal semiconductor, so that the field strength at the receiving end of the joint is evenly distributed.

3. Processing of external semiconductor shielding

The external semiconductor shield is a semi-conductive material that produces a uniform electric field effect outside the insulation of cables and connectors, which is the same as the internal semiconductor shield and plays a very important role in the cables and connectors. The external semiconductor port must be neat and uniform, and the smooth transition with the insulation is required, and the semiconductor tape is wound at the joint and the semiconductor shield outside the cable body is connected.

4. Metal shielding and grounding treatment

The effect of metal shielding in cables and termination is mainly used to conduct the cable fault short-circuit current, as well as the electromagnetic interference of shielding electromagnetic fields on adjacent communication equipment, the metal shielding in the running state is at zero potential in a good grounded state, when the cable fails, it has the ability to conduct short-circuit current in a very short time. The ground cable should be securely welded, the metal shielding and armor tape on the cable body at both ends of the box should be solidly welded, and the termination should be securely grounded.