1. Silicone rubber in the field of insulators in composite applications
At present, the external insulation materials of power transmission and transformation equipment mainly include ceramics, EPDM rubber, epoxy resin and silicone rubber. Because silicone rubber has outstanding advantages in cracking resistance, hydrophobicity, antifouling, leakage resistance and electrical corrosion resistance, it has gradually replaced other materials and become the insulation material prepared by composite insulators. The latest research found that adding a small amount of siloxane oligomers can give silicone rubber for composite insulators stable and durable hydrophobic migration. When combined with siloxane oligomers with different polymerization degrees, silicone rubber in addition to having better hydrophobic migration, hydrophobic durability and aging resistance are also greatly improved. There was no significant change in the hydrophobicity of the samples after aging for 2500h and 5000h.
2. Application of silicone rubber in the field of cable accessories
Various terminal heads and intermediate connection heads in the cable line are collectively referred to as cable accessories. Cable accessories are necessary devices to connect cables and devices to achieve power transmission. The application development of silicone rubber in cable accessories has experienced three stages: heat shrink type, prefabricated type and cold shrink type. At present, the silicone rubber cable accessories on the market are basically cold shrink type. 10~35 kV wire network can be separated shielded cable accessories with silicone rubber, not only has a high insulation resistance, and continuous use at -50 ~180℃ for more than 20 years without loss of elasticity, but also has good thermal conductivity, hydrophobicity and excellent mechanical properties. Thermal aging is an important factor affecting the operational reliability of silicone rubber used in ultrahigh voltage cable accessories.
3. Application of silicone rubber in the field of antifouling flashover coating
The aggravation of environmental pollution makes the insulation of transmission and transformation lines decline, which is easy to cause pollution flashover accidents and bring serious losses. One of the current measures to prevent pollution flashover is to apply RTV silicone rubber paint. However, RTV silicone rubber coatings suffer from wind, sun, rain, discharge ablation and other erosion for a long time in the process of use, and will appear cracking, peeling, electrical erosion, and hydrophobic performance decline, and will cause pollution flash due to failure to a certain extent. In order to further improve the performance of RTV silicone rubber coating, a lot of research has been done on the properties and influencing factors of silicone rubber used in antifouling flashover coating. It was found that the higher the silica content, the higher the thermal conductivity, the stronger the resistance to electric marks and arc ablation. The hydrophobicity, oil resistance, flame retardancy and self-cleaning property of the coatings can be significantly improved by adding the composite flame retardants of nano-scale vapor phase white carbon black, inorganic matter and organic matter into the formulation. The addition of fluorine atoms makes the coating have a low surface energy, and the ice has a small adhesion on its surface, which can fall off under the action of natural forces and play a role in preventing ice.
With the deepening of research and the continuous improvement of product performance, silicone rubber will be more and more widely used in the power industry, especially in the fields of composite insulators, cold-shrink cable accessories, transformers, transformers, anti-pollution flash coatings and so on.
