中文 
English
Insulation breakdown is one of the main quality accidents of cold-shrinkable cable accessories, which is what we often call "explosion". In addition to material quality and production process reasons, the production and installation factors are greater. According to the data of relevant field personnel and researchers, the reasons are as follows:
Due to the poor operating environment of cold-shrinkable cable accessories, the junction between the semiconductor and the main insulation surface will inevitably invade the dust layer/gas and other magazines. Impurities, air gaps, and sharp burrs are the main reasons for the surface discharge of the solid insulation medium. Moreover, for the cut-off of the cable shielding layer, the electric field distortion will cause electric stress concentration. The electric field strength is the weak link of the entire joint. It is particularly easy to assemble the cold shrinkable cable terminal and the cold shrinkable cable intermediate joint insulation breakdown, or just a kind of Overheating burst phenomenon. Specifically, in addition to environmental factors, the installation factors are as follows:
1. When the inner sheath is peeled off, the shielding layer will be scratched, and the electric field strength at the fracture will increase, which is easy to discharge.2. When peeling and cutting the copper shield, improper force will scratch the semiconductor layer and there will easily be an air gap.
3. Improper force when stripping the semiconducting layer of the cable will cause scratches on the surface of the main insulation layer and easily produce air gaps.4. There are sharp corner burrs at the shielding disconnection and the semiconductor layer disconnection and untreated and smoothed.
5. After the cable semiconductor shielding layer is stripped, it is not cleaned, the semiconductor remains on the main insulation, or there is no early installation requirement when cleaning, or the main insulation and shielding fractures are not filled with silicone grease, leaving hidden dangers. Generate flashover discharge.6. When installing cold shrinkable accessories, the stress cone part is not installed properly, or even damaged, resulting in an air gap, resulting in failure of the stress control component.
When there are the above installation problems, it will cause electric field concentration, especially during operation, heating and cooling effects, bending effects, etc. will add air gaps. Even if breakdown cannot occur immediately, electrical branches will be formed inside the main insulation layer and As it develops in depth, the insulation layer accelerates aging. Or if the cleaning is not in place, the main insulation is injured, which will reduce the breakdown strength of the main insulation. Under the repeated action of so many factors, the breakdown of cold-shrinkable cable accessories occurred.
Therefore, during installation, you must follow the process specifications and operate carefully. If this happens, you should first find the reason for the installation, and then check the material and design and manufacturing process of the cold cable accessory itself.
