Effect of Silicone Grease Coating on Space Charge Characteristics of XLPE / SIR Interface

Silicone rubber (SIR) for cable accessories insulation is easy to absorb the silicone grease coated on the interface between accessories and cable insulation to swell, thus affecting the interface charge characteristics. In order to study the effect of silicone grease coating on the spatial charge distribution of the cross-linked polyethylene (XLPE) / SIR interface under different aging methods, two silicone greases with large polarity difference were selected, one was ordinary silicone grease, and the other was silicon fluoride grease with large polarity. The silicone rubber coated with silicone grease was subjected to normal temperature aging, corona aging and wet aging, respectively. The spatial charge distribution of the XLPE / SIR sample coated with silicone grease was measured by electroacoustic pulse method (PEA). The results show that under different aging conditions, the charge polarity accumulated at the interface of the samples coated with two kinds of silicone greases is mainly positive polarity, that is, the polarity is the same as the polarity of the electrode on the side of the silicone rubber, and the silicone grease with larger polarity makes the interface of the samples easier to accumulate charge. Under different aging modes, both silicone resins have swelling effects on silicone rubber, resulting in the migration of positive charges at the XLPE / SIR interlayer interface to silicone rubber. The interface charge accumulation caused by wet aging is the largest, followed by room temperature aging, and finally corona aging.