Study on Conductivity Characteristics of LDPE/SiO2 Nanocomposite at High Temperature

The development of high-voltage DC cables is mainly limited by the properties of insulating materials. Adding an appropriate amount of nanoparticles can improve the dielectric properties of materials. To study the effect of high temperature and nano-filler concentration on the conductivity characteristics of the dielectric, LDPE/Sio
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nanocomposites with the particle size of 7 nm and mass fraction of 0.5wt%, lwt%, and 3wt% were prepared by filling LDPE with nano- Sio
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particles. The DC conductance at 90°C and 100°C was measured at the electric field strength of1-100 kV/mm, and the temperature sensitivity of the samples were analyzed. The results show that in the condition of high temperature and low electric field, the nanocomposite can effectively reduce the conductivity current density and improve the conductivity performance, and the first threshold electric field increases with the increase of nano-filling concentration. Under the high electric field at high temperatures, temperature becomes one of the main factors that affect the carrier transport process. Among all samples, the LDPE/Sio
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nanocomposite with a mass fraction of 3wt% has the best conductivity and the lowest temperature sensitivity.