Investigation of partial discharge pulse shapes occurring at interfaces in model joints

The understanding of degradation processes in transmission-class cable joints is very important to the reliability of the operating system. Degradation caused by partial discharges (PD) and their associated characteristics were investigated in model "pre-fabricated" cable joints. Time to breakdown and PD pulse parameters such as rise time, width, fall time, amplitude and frequency were studied. The paper further describes PD pulse parameters occurring within different part of cable joints, such as within the epoxy casting near the high voltage electrode and along the EPR-epoxy interfaces.