What are the types of high-voltage power cable connectors
The high-voltage power cable connector is used for the connection of the power cable itself. There are connection joints, insulating intermediate joints, and plug joints for oil-filled power cables and steel pipe power cables.
1. Ordinary connector
It is used to connect two adjacent power cables.
In the high-voltage power cable line, in addition to connecting the cable core conductor to ensure electrical communication, the straight-through joint must maintain the oil flow in the core of the self-contained oil-filled power cable connector. However, because the connector is manually operated on site, its process conditions are poor. Therefore, under the condition of crimping the core connection, the problem of electric field concentration at the core connection is handled, and the insulation thickness is increased to reduce the working field strength of the joint to ensure the safe operation of the connector. Usually, the insulation of the power cable is wrapped to increase the insulation, and the two ends of the increased insulation form a tapered stress cone. The insulation shield is wrapped around the increased insulation to connect the insulation shields of the power cables at both ends, and there is an outer bright steel pipe outside to isolate the insulation from the atmosphere, so that it can withstand the oil pressure of the oil-filled power cable.
2. Insulated joint
The insulation structure and size of the insulation joint are the same as the ordinary joints. 110 ~ 220kV oil-filled power cable insulated joints are mainly used in long-length power cable lines to electrically disconnect the metal sheath or metal shielding layer and semi-conductive layer of the power cable at both ends of the joint to facilitate cross-interconnection and reduce Protective layer (or shielding layer) loss.
3. Plug-in connector
The plug connector is the weakest link in the electrical performance of oil-filled power cable accessories, and it is also the connector with the most complicated structure. It is mainly used to cut off the oil circuit in the power cable line of the impregnated paper insulated power cable where the drop is greater than the specified value to prevent the high-end power cable insulation from drying out and the low-end power cable insulation oil pressure to exceed the specified value.
The 110kV single-chamber plug-and-stop middle joint usually uses an epoxy resin sleeve to separate the oil flow of the two power cables.
The 220kV double-chamber plug-stop middle joint uses two epoxy resin sleeves to separate the oil flow of the two power cables. There is an outer cavity above the plug pipes of the two power cables, two inner cavities containing power cables and One outer cavity is connected with oil flow and has two sealing structures.
4. Steel pipe oil-filled power cable joint
There are two types of copper pipe oil-filled power cable joints: ordinary connection joints and half plug joints.
Ordinary connection joint is used for the length connection of power cable manufacturing. Its internal insulation structure is generally interphased with the self-contained oil-filled power cable joint. Its shell is a copper tube with a diameter slightly larger than the power cable duct. Half plug connector, used for long steel pipe oil-filled power cable lines. It is a joint designed to avoid the loss of a large number of power cable sleeves in the event of an oil leakage accident. It is used to separate the oil supply section and allow the oil in the two sections to circulate through the power cable insulation layer or bypass pipe. At the junction of the joint steel pipe and the power cable steel pipe, a sealing structure is used to separate the power cable oil circuit.