MV Cable, also known as Medium Voltage Cable, refers to power cables with a rated voltage between 6kV and 35kV, typically used for transmitting medium voltage electricity. Typically, the most common specifications for medium voltage cables include 11kV copper cable, 15kV medium voltage cable, and 35kV mv cable
In the installation of power engineering, medium voltage wire terminal joints and intermediate joints are important components of power equipment in transmission and transformation cable lines. Their function is to disperse the electric field at the external shielding and cutting point of the cable terminal head, protect the MV cable from breakdown, as well as provide internal and external insulation and water resistance.
1. MV power cable conductor connection: The conductor connection requires low resistance and sufficient mechanical strength, and there should be no sharp corners at the connection.
2. Internal semiconductor shielding treatment: As you know, medium voltage cable specifications include unshielded medium voltage cables and unshielded medium voltage cables. For any type of medium voltage cable with an internal shielding layer, the internal shielding layer of the crimping tube conductor must be restored when making the joint. A portion of the internal semiconductor shielding of medium voltage cables must be left to ensure that the internal shielding of the connection tube can be connected to each other, ensuring the continuity of the internal semiconductor and evenly distributing the field strength at the joint.
3. The treatment of external semiconductor shielding: External semiconductor shielding is a semiconductor material that acts as a uniform electric field outside the cable medium voltage and joint insulation. Like internal semiconductor shielding, it plays a very important role in MV cables and joints. The outer semiconductor port must be neat and uniform, and it is required to have a smooth transition with insulation. A semiconductor strip should be added to the joint to connect with the outer semiconductor shielding of the MV cable body.
4. Treatment of medium voltage cables reaction cone: During construction, the shape and size of the reaction cone should be as accurate as possible, and the potential distribution on the entire cone surface should be equal. When making cross-linked cable reaction cones, special cutting tools are generally used, or slightly heated with low heat and cut with a fast knife. After the basic shape is formed, it should be scraped with 2mm thick glass, and finally polished with sandpaper from coarse to fine until smooth.
5. Metal shielding and grounding treatment: The main function of metal shielding in medium voltage power cables and connectors is to conduct short-circuit currents in MV cables and shield electromagnetic interference from nearby communication equipment. In operation, the metal shielding is at zero potential in a well grounded state. When the MV cable fails, it has the ability to conduct short-circuit currents in a very short period of time. The grounding wire should be reliably welded, and the metal shielding and armor tape on the MV cable body at both ends should be firmly welded. The grounding of the terminal should be reliable.
6. The sealing and mechanical protection of joints are the guarantee for ensuring the safe operation of medium voltage cables. Moisture and moisture should be prevented from seeping into the MV underground cable joint. In addition, joint protection grooves or cement protection boxes should be built at the joint position
