Microvaristor based field grading elements for HV terminations

摘要

A novel nonlinear resistive field gradingrnelement for cable accessories is discussed. Thernmaterial consists of a silicone matrix filled withrnmicrovaristor particles based on doped and sinteredrnZnO, that show a highly nonlinear current-voltagerncharacteristic. Because their electrical properties canrnbe specifically designed by variation of the doping andrnthe sintering process, one is able to adjust the materialrnproperties according to the electrical requirements ofrnthe specific application. This advantage can be utilizedrnin the design and optimization process of cablernaccessories. For illustration, preliminary results on therndevelopment of a HV termination containing the newrnfield grading element are presented, with some focusrnon the interplay between numerical simulations andrndesign engineering.