Key points analysis of installing cable joint in electric power construction

In the power engineering installation, the cable terminal head and the middle cable connector are important power equipment components in the power transmission cable line. Its function is to disperse the electric field at the cutoff of the cable terminal head shield and protect the cable from breakdown. With internal and external insulation and waterproof effect. In the cable line, more than 60% of the accidents are caused by accessories, so the quality of the fittings is very important for the safety and reliability of the entire power transmission.

1, the conductor connection The conductor connection requires low resistance and sufficient mechanical strength, the connection can not appear sharp corners. Low-voltage cable conductor is commonly used in crimping, crimping should pay attention to:

(1) Select the appropriate conductivity and mechanical strength of the conductor connecting pipe;

(2) The inner diameter of the crimping pipe and the outer diameter of the core to be connected with the take 0.8 to 1.4mm gap;

(3) The resistance value of the joint after crimping should not be more than 1.2 times of the conductor of the same section, the tensile strength of the copper conductor joint should not be lower than 60N / mm2;

(4) Before crimping, the outer surface of the conductor and the inner surface of the connecting pipe are coated with conductive glue, and the wire brush damages the oxide film;

(5) connecting pipe, core conductor sharp corners, burrs, etc., polished with a file or sandpaper smooth.

2, the semiconductor shielding process Where the cable body has an inner shield, the connector must be restored in the manufacture of connectors pressure conductor portion of the shield, the cable must be set aside part of the internal semiconductor shield in order to make the connector on the connector The inner shields are able to communicate with each other to ensure the continuity of the inner semiconductors so that the field strength at the joint connector is evenly distributed.

3. Outer Semiconductor Shielding Outer semiconductor shielding is a semi-conductive material that acts as an even electric field on the outside of the cable and cable connector insulation. As with the inner semiconductor shield, it plays a very important role in cables and connectors. The external semiconductor ports must be neat and uniform and also require a smooth transition to the insulation and the semiconductor tapes are wound around the cable gland and the semiconductor shield on the outside of the cable.

4, the cable reaction cone processing construction shape, make inch accurate reaction cone, in the entire cone surface potential distribution is equal, in the production of cross-linked cable reaction cone, the general use of special cutting tools, can also be used Micro heat slightly heating, cutting with a sharp knife, the basic shape, then 2mm thick glass repair scratch, and finally sandpaper from coarse to fine grinding until smooth.

5, metal shielding and grounding metal shield in the role of the cable and connector is mainly used to conduct short-circuit current cable fault, as well as the electromagnetic shielding electromagnetic field near the communications equipment, metal shield in good grounding in the operating state at zero Potential, when the cable fails, it has the ability to conduct short-circuit current in a very short period of time. Grounding wire should be reliable welding, metal shield and armored belt on both ends of the cable box body firmly welded, the grounding of the terminal should be reliable.

6, the joint seal and mechanical seal The seal and mechanical protection is to ensure safe and reliable operation of the joint protection. Should prevent infiltration of moisture and moisture within the cable connector, the other in the joint position should be built connector protection slot or install cement protection box.