Preparation and performance of a low relative permittivity insulation paper

SiO₂ hollow spheres and K-SiO₂ insulation paper handsheets composed of these SiO₂ hollow spheres with different weight percentages were synthesized. SiO₂ hollow spheres with a low content were uniformly dispersed. However, the SiO₂ hollow spheres locally aggregated with increased concentration. The relative permittivities of the immersed oil K-SiO₂ handsheets initially decreased and then increased with increased SiO₂ hollow sphere content. K-5% SiO₂ had the lowest relative permittivity. Simulation analysis indicated that the electric field distribution between the two test electrodes was uniform. The breakdown voltage of the paper-oil-paper composite insulation system increased with decreased relative permittivity of the paper. The breakdown voltage of the composite insulation system increased from 26.4 kV to 30.5 kV when the relative permittivity of the paper decreased from 2.55 to 1.68. The experimental results were also consistent with the theoretically calculated data. And in the paper-oil-paper composite insulation system, the electric field strength of the oil gap decreased with decreased relative permittivity of the paper.