In the case of high-voltage transmission line construction, many people working on projects often come across high-voltage power cable joints. Today, I would like to discuss the types of high voltage power cable joints and their applications with you. First, let’s talk about what high voltage power cable joints are.
High Power Cable Joint
High-voltage power cable joints are used to connect power cables, including joints and insulated intermediate joints. For oil-filled power cables and seamless steel power cables, there are also plug joints and other joints.
1. General joint
It is used to connect two adjacent power cables.
In the high-voltage power cable route, in addition to connecting the electrical conductor of the cable core to ensure the connection of electrical equipment, the joint of the self-capacitating oil-filled power cable must maintain the oil row in the core smoothly. But because the joint is handmade in the field, its processing standards are poor. Therefore, the core connection on the line is selected under the riveting standard, and the electrostatic field concentration problem at the single pick core connection is solved by enhancing the insulation thickness and reducing the magnetic field strength in the joint work to ensure the safe operation of the joint. Generally, the insulation of high-voltage power cables is wrapped around the top side of the winding insulation, and the two sides of the winding insulation produce a cone-shaped surface ground stress cone. The insulation shield is wrapped around the outside of the insulation to connect the two sides of the power cable insulation shield. And its outer edge has an outer bright seamless steel pipe to insulation and air barrier so that it can bear the vapor pressure of the oil-filled power cable.
2. Insulation joint
Insulation joints have the same structure and specifications as general joints. 110 ~ 225kV oil-filled power cable insulation joints are used in large and short power cable routes. So that the joints on both sides of the power cable metal material sheath or metal material shield off layer and semi-conductivity layer in the electrical equipment break off, to facilitate cross-type interconnection, reduce the outer sheath (or shield off layer) wear and tear.
3. Plug stop type joint
The plug stop type joint is the most lacking stage of the electrical performance of oil-filled power cable fittings and is also the most complicated construction of the joint. It is the key to be used to undulate more than the standard value of crafty prep reg paper-insulated power cable route, disconnect the oil channel, to avoid the insulation of high-grade power cables becoming dry, low-end power cable insulation vapor pressure exceeds the standard value.
115kV one-chamber plug stop positive intermediate joint, generally with an epoxy resin rubber waterproof sleeve to separate the oil row of the two power cables.
225kV double chamber type plug stop positive intermediate joint, with two epoxy resin rubber waterproof casing to separate the oil row of two power cables, in several sections of the power cable plug stop tube on the upper side of an outer cavity, two with the inner wall of the power cable and an outer cavity oil row interoperability, is two sealed structure.
4. Seamless steel pipe oil-filled power cable joints
There are two kinds of air-conditioning copper tube oil-filled power cable joints: general connection joints and half stop joints.
General connection joint, used for power cable production and manufacturing of short and long connections, its internal insulation structure is generally the same as the self capacitative oil-filled power cable joints of two colors, its housing is a diameter slightly more than the power cable pipeline of air-conditioning copper pipe. Half plug stops joint for longer seamless steel pipe oil-filled power cable routes. It is a joint designed to prevent the outflow of many power cable sleeves once an oil seepage safety accident has occurred and designed to separate the oil sections provided so that the oil in both sections flows through the power cable insulation or bypass tube commodity. In the seamless steel pipe of the joint and the seamless steel pipe of the power cable connection, the sealing structure is selected to separate the power cable oil channel.
