How to choose a cold shrink cable accessory
How to choose a cold shrink cable accessory——Requirements for cable plug sealing
The 10kV cable connector has strict sealing requirements. The intrusion of moisture can cause the insulation of the cable connector to drop, which eventually leads to breakdown of the cable accessory. The national standard GB12706.4 clearly stipulates that the cable accessories should be subjected to 30 constant voltage load cycle tests in water. The American and European cable joints are made of rubber and use rubber resilience to achieve a sealing effect. The operation of more than ten years has proved to be safe and reliable. Some domestic manufacturers use epoxy resin and seal ring to achieve a good sealing effect.
How to choose a cold shrink cable accessory——Requirements for cable connector plug shield
The 10kV cable connector should be shielded as much as possible. The shielding layer of the cable connector acts as a shield and a uniform electric field. The shielding layer has zero potential through the grounding surface. People can avoid the risk of electric shock when the device is charged, and it can operate safely under harsh environment (flood, humidity). In the manufacturing process, the shielding layer is vulcanized by a thicker shielding layer and an insulating layer, and the shielding layer is over-vulcanized, and even a semi-conductive paste is applied to the insulating layer. The first process has a thick shielding layer and is tightly combined with the insulating layer, and has a high partial discharge performance. The other two methods do not meet the requirements for safe operation.
How to choose a cold shrink cable accessory——Requirements for technical indicators
According to the requirements of national standard GB12706.4, the domestic 10kV cable system adopts 8.7/15kV grade cable accessories, the AC withstand voltage level is 40kV, 5 minutes, and the partial discharge level is 15kV, ≤10Pc. Type test should be carried out in air and water. 30 constant pressure load cycle tests. Dynamic thermal stability current should generally be greater than 20kA, 2 seconds, 200A elbow plug should be selected according to the actual situation of the system.
How to choose a cold shrink cable accessory——Requirements for rubber types
There are two types of rubber currently used in cable accessories: one is EPDM rubber and the other is silicone rubber. These two rubber materials each have their own characteristics. EPDM rubber has excellent insulation performance, strong aging resistance, but poor UV resistance. Silicone rubber has good weather resistance and good insulation performance. EPDM rubber is widely used in making cable connectors abroad, because the plug is generally not exposed to ultraviolet light from the sun, and is the best material for making cable connectors. The cable shrinkage/prefabricated outdoor terminal head should be made of silicone rubber, making full use of its UV resistance and good water repellency.