Surface Discharge Behaviours, Dielectric and Mechanical Properties of EPDM based Nanocomposites containing Nano-BN

Surface discharge often occurs between a solid dielectric and high voltage conductor which is one of the major insulation failure modes. In this paper, surface discharge characteristics (phase resolved patterns, magnitude and repetition rate) of EPDM/BN nanocomposites are studied. Also investigated are the dielectric response, volume resistivity and mechanical properties. Surface modified boron nitride (BN: 50 nm) particles are procured for the fabrication of nanocomposites. Samples are exposed to surface discharges using the IEC (b) electrode configuration and partial discharge (PD) measurements are done according to IEC 60270 Standard. Experimental results proclaimed that PD behaviours depend on the nanoparticle loading in the EPDM. The PD inception voltage improves with increasing filler content up to 7 wt% and discharge integrated parameters are remarkably lower. Embedded nanoparticles strengthen the barrier resistance of the nanocomposites, which may help in reducing the net electric field in the air gap and thus mitigate the PD intensity. The permittivity value at power frequency follows a similar increasing trend up to 5 wt% then drops whilst the dielectric loss is the lowest for the 1 wt%. Consistent improvement in volume resistivity and mechanical tests results are observed with BN-contents.