Abstract
This research is carried out to analyze the treeing degradation phenomena with a needle shape void by a discharge magnitude and a discharge luminous quantity at each phase angle of an applied voltage. Discharge pulses and discharge luminous images are measured by original measurement system for measuring the discharge magnitude and the discharge luminous image according to several phase angle area of the applied voltage. Each phase angle area is named Φ1-Φ20 in order from the negative peak point to the next negative peak point of the applied voltage. The luminous image is digitized to the luminous quantity with a computer after experiment. In this study, we focused on the product of instantaneous value and dv/dt at the applied voltage. The resuks obtalned are as follows. The discharge magnitude and the luminous quantity are the maximum at phase angle areas of Φ7 and Φ17. We deflne an effective instantaneous value that includes a voltage of residual electrical charge. The discharge magnitude closely correlates the effective instantaneous value × dv/dt. It is important to measure the discharge quantities at each phase angle area for analyzing the treeing degradation phenomena.
