Firstly, a product with a specific shape is processed with conductive rubber, which is generally called conductive cone.

Secondly, the conductive cone is sheathed on the mandrel of the non repaired steel mold, injected with insulating rubber, heated and vulcanized to form the rubber electrical stress control cone.

③ electrical performance index of rubber stress control cone, taking the stress cone for 110kV cable terminal as an example: the basic electrical parameter requirements of the stress cone for 110kV cable terminal are: no discharge for 30 minutes under the power frequency voltage of 160KV, no partial discharge for 96kv beyond the background under the condition of background partial discharge of 5pc; only the rubber stress control cone passing the above two tests can control the electric field at the end of the cable The role of.

The difficulty of manufacturing rubber electrical stress control cone lies in the quality control of the interface between insulating rubber and conductive rubber. If there are air gap, bubble, dent and other defects between the interfaces (lines), the electrical stress control cone will not pass the electrical performance test. We have found in many years of practice that as long as there are defects between the stress cone insulating rubber and the conductive rubber, the partial discharge under 96kv power frequency voltage must be more than 5pc.

⑤ State Grid Electric Power Research Institute

The State Key Laboratory of power generation equipment safety control and Simulation of Tsinghua University has carried out the simulation test on the silicon rubber stress cone of high-voltage cable accessories, simulated two kinds of defects: bubble and air gap crack, measured the initial voltage of the electrical tree under the power frequency voltage, recorded the shape of the electrical tree through the digital microscopic observation system, and studied the influence of the defects on the initial characteristics of the electrical tree of silicon rubber The results show that the initial voltage of electrical tree decreases when there are bubble defect and air gap crack defect.

⑥ Tianjin power supply company analyzed several samples of defects in the operation of XLPE insulated cable system: it was pointed out that improper handling of the joint surface between accessories and cables and the formation of air gap was one of the main causes of cable system failure.