Space charge measurement of vegetable oil filled with BN nanoparticles by thermal step method

Abstract

Vegetable oil is considered as the substitute of traditional mineral oil serving as the insulation medium due to the considerable dielectric property and the excellent biodegradation. The vegetable oil filled with boron nitride (BN) nanoparticles showed significant improvement in both thermal and dielectric properties in previous study. Thereby, in this paper, the experiment for space charge measurement of the nano-modified vegetable oil was conducted by thermal step method (TSM) to investigate the influence of BN nanoparticles on the charge distribution in the oil. BN nanoparticles with different mass fractions were dispersed in the origin oil and the space charge distribution was obtained after the sample was short circuited. DC voltages with various magnitudes and times was applied in charging process and showed obvious influence on the charge accumulation. Results showed that the charge density was reduced with the addition of BN nanoparticles as the consequence of the alternation in trap depth and the transportation and dissipation of the corresponding charge.