Insulating polysiloxane coating forXLPE‐Si‐rubber interfaces with high long‐term stability

Abstract

Cable joints play an important role in the power supply systems, but at the same time, they greatly contribute to the majority of direct failures. Weak parts of the cable lines, especially for the solid‐solid interfaces in joints, attract much attention and are investigated by researchers worldwide. High‐voltage power transmission in electrical grids requires reliable and durable dielectric coatings for the interface insulation. The breakdown caused by local electric field enhancement is a gradual damaging process that leads to structural degradation and an increase of electrical conduction of dielectric materials, and ultimately, it results in catastrophic failure of the cable joints. Here, we demonstrate that the coating of silicone gel instead of silicone grease enables the improvements of tangential AC (alternating current) BDS (breakdown strength) and long‐term stability in the interfaces of joints. Under the pressure of Si‐rubber (silicone rubber) cold‐shrinkable cable accessories, the silicone gel almost did not lose, which improved the insulating stability of the interfaces. Our method allows us to fill the XLPE‐Si‐rubber (cross‐linked polyethylene and silicone rubber interfaces with silicone gel instead of silicone grease), which could reduce the risks of the power outage caused by cable joint faults.

Voltage stabilizer and nanofiller in enhancement of insulation properties of cross‐linked polyethylene

“…Different nanofillers and concentrations have different effects on the electrical properties of the insulating materials. [12][13][14] However, the uniform dispersion of the nanofillers and their compatibility with polymeric materials are major issues. 15 Moreover, the long-term stability of nanofillers and voltage stabilizers and their possible reaction with antioxidants and crosslinking agents need rigorous research.…”

“…Anh et al 11 reported that adding different concentrations of nano TiO 2 reduced the breakdown voltage of LDPE. Different nanofillers and concentrations have different effects on the electrical properties of the insulating materials 12–14 …”

“…However, the uniform dispersion of the nanofillers and their compatibility with polymeric materials are major issues 15 . Moreover, the long‐term stability of nanofillers and voltage stabilizers and their possible reaction with antioxidants and crosslinking agents need rigorous research 13,16 . Besides, no study has reported the effect of the simultaneous addition of voltage stabilizer and nanofiller to the XLPE.…”

“…15 Moreover, the long-term stability of nanofillers and voltage stabilizers and their possible reaction with antioxidants and crosslinking agents need rigorous research. 13,16 Besides, no study has reported the effect of the simultaneous addition of voltage stabilizer and nanofiller to the XLPE. We believe that such an innovative attempt can help the researchers and industry to further investigate the possible synergistic effect of these two additives on improving the electrical properties of the XLPE.…”

Morphology evolution and breakdown mechanism of cross‐linked polyethylene (XLPE)–silicone rubber (SiR) interface induced by silicone grease diffusion

“…During the installation of cable accessories, the XLPE surface is coated with silicone grease (SG) for lubrication and sealing [17]. This SG coating has been shown to effectively increase the breakdown voltage of the XLPE–SiR interface; however, the SG can migrate into the SiR and cause swelling [18, 19]. Zhu et al showed that in addition to swelling of the SiR, the SG coating can lead to decreased hardness, tensile strength at break, and elongation at break of the SiR [20].…”