Plasma Repair of Insulation Crack Defects for Cable Accessories

In order to study the application effect of plasma technology in repairing defects of cable accessories, a research of plasma repair on crack defects of cable accessory insulation was carried out. The experimental samples are silicone rubber (SIR) insulation taken from cable accessories, tetraethyl orthosilicate (TEOS) and butyl methacrylate (BMA) are selected as two different precursors in plasma processing, and the processing time for defect samples is 2 min, 4 min and 6 min, respectively. The Fourier transform infrared (FTIR) spectroscopy, flashover voltage, breakdown field strength and surface potential attenuation of the insulation samples before and after repair were tested respectively. Plasma repair can effectively improve the flashover voltage and breakdown field strength at the surface defects of SIR insulation. The rejuvenation effect with BMA is not as good as that with TEOS. After plasma repair with TEOS as the precursor, the electrical properties of SIR insulation are improved significantly, and the breakdown strength of the samples repaired by TEOS for 4 minutes is slightly higher than that of the intact samples. Due to the close chemical composition, plasma repair with TEOS does not introduce new groups, meanwhile the main and side chain structure of SIR remains relatively intact. Plasma repair with BMA introduces C=O and - CH2 on the insulating surface, and the damage of the Si-O-Si main chain increases with the increase of repair time.