Dielectric properties of LDPE/MgO nanocomposite material under AC high field

Low density polyethylene (LDPE) is widely used as a dielectric insulation of power cable. It has already reported that an incorporation of MgO nano particles in LDPE matrix could provide dielectrics with new and improved properties under dc high field. This paper describes high field dielectric properties of LDPE/MgO nano composite material under ac high voltage application. From the results of dissipation current waveform observations under ac high field, the volume resistivity and the relative permittivity for various contents of MgO nano particles in LDPE were estimated at the applied frequency 50 and 200 Hz. Though, the dependences of MgO content on both volume resistivity and relative permittivity under ac high field at 50 and 200 Hz are recognized, but it seems not to be drastically improved by adding a few percent of nano-size filler like those under dc high field.