Experimental study on the electrical and thermal properties of epoxy-crepe paper composites for use in UHV DC bushing condensers

Entire performance of UHVDC resin impregnated paper (RIP) bushings in operation condition has an intimate connection with electrical and thermal properties of epoxy/crepe paper composites used in bushing condenser. Firstly, some samples of pure epoxy and epoxy/crepe composites which are identical to those used in actual RIP bushings were fabricated. Then micro morphology of these samples has been observed by scanning electron microscopy (SEM) and polarized light microscopy (PLM). Some electrical performance measurements were carried out including AC breakdown characteristics, bulk resistivity versus temperature characteristics and dielectric spectroscopy with broadband dielectric spectra. Meanwhile, thermal property containing thermal conductivity versus temperature characteristic has also been obtained experimentally. Finally, with these parameters of composites, electric field and temperature distribution inside bushing condenser has also been simulated by finite element method (FEM).