The study of epoxy nano micro composites clearly indicates that the material has better dielectric properties with a good discharge resistance and less surface charge accumulation on its surface. The impact of high-frequency AC voltage and the percentage of ripple content in DC voltage on corona inception caused by water droplets was analyzed. Under a high frequency, the variation in the shape of the water droplet is the same as that under 50 Hz AC voltage. The UHF signal radiated due to water droplet initiated discharges have signal bandwidth in the range of 300 MHz-3 GHz. The influence of corona discharge on surface properties of the material, its variation to contact angle and water droplet initiated corona activity under AC voltage was analyzed. The surface potential characteristics were altered with corona-aged specimen. The impact of an ion-trapping particle on nanocomposites clearly exhibits its characteristics through surface potential studies. Water diffusion into the insulating materials varies with the type of filler material. The temperatures measured during arcing, analyzed through laser-induced breakdown spectroscopy (LIBS), were correlated with the hardness of the material. In addition, the mechanical properties, especially storage modulus and tan δ, were analyzed through dynamic mechanical analysis (DMA) studies. © 1994-2012 IEEE.