Annual Report

absorption ageing Appl applied voltage band breakdown voltage cable capacitance capacitor cathode characteristics charge injection circuit conductivity contaminated curve dB/km decrease density dependence diameter dielectric constant dipole effect electric breakdown electric field Electrical Insulation electrode electron avalanches energy epoxy equation eV band experiment experimental Figure film flashover flashover voltage fluid frequency function heating high voltage IEEE Trans induced loss initial insulation ions irradiation layer LDPE liquid loss increase material measured mechanism method mixture NBOHC needle negative observed obtained occur optical fibers oxidation parameters partial discharges peak permittivity Phys polarization poling polyethylene polymer positive pressure pulse PVDF radiation resistance reignition resin room temperature sample shown in Fig shows silica silica core silicone space charge specimens spectra streamer stress surface potential thermal thickness tion transducer vacuum values varistor wavelength XLPE