The Influence Of Nanoparticles On Insulation Properties Of Natural Ester

Natural ester is a new kind of environmentally friendly insulating material and has been applied in power industry. However, the low the tolerance of ester for lightning may limit its application in extra high voltage level. So it is of high siganificance to improve the insulation of ester, not only for the guarantee of safe operation of transformer but also to ruduce the size of ultra-high voltage transformer and cost in investment.In order to improve the insulation of natural ester, this paper has added TiO2nanoparticles into ester to obtain an ester-based nanofluid. AC, lightning impulse voltage and partial discharge tests were applied to the natural ester and the ester-based nanofluid to check their dielectric performances. On this base, the effect of nanoparticles on the progress of streamer was studied by the use of ICCD camera. Moreover, pulse electroacoustic technique (PEA) and thermally stimulated current method (TSC) were brought in to have a look at charge transportation and electric trap in ester.Research results indicate that TiO2nanoparticles can enhance insulating properties of ester. AC breakdown voltage of ester-based nanofluid is1.24times as that of natural ester, lightning breakdown of ester-based nanofluid can be enhanced to1.19times, while partial discharge initial voltage is as high as1.05of nautral ester. Further research indicates that nanoparticles can surpress fast streamer propagation and the streamer progress channel is wider and the propagation time is longer in ester-based nanofluid. Moreover, pulse electroacoustic technique (PEA) tests and thermally stimulated current method (TSC) tests show that TiO2nanoparticles can accelerate charge dissipation, decrease the strength of electric fields and increase shallow trap obviously.Based on the experiments, it is believed that the addition of TiO2nanoparticles increase the density of shallow trap in ester. For the shallow trap, the progress of capture and release can accelerate charge transportation, thus reducing space charge, weakenning the electric field on the top of treamer, surpressing its further developing. So the insulating properties are improved.