Characteristics of PD pulse sequence and single-pulse light emission in artificially-simulated tree channel

Abstract

In order to clarify the mechanisms of partial discharge (PD) and tree degradation in an electrical tree, PD's in an artificially-simulated tree channel connected to a pin-electrode in LDPE were investigated. This paper discusses the characteristics of PD's which take place when a tree propagates from the tip of artificial channel by utilizing PD pulse sequence and single-pulse light emission. The PD pulse sequence showed that large and small PD's took place in a half cycle. The magnitude of positive PD pulses changed regularly in a half cycle. Each positive PD pulse took place when the applied voltage increased by a constant value. There was no correlation between the voltage increment and the PD magnitude. The conventional simple PD model can not explain these results. The light emission from a single PD pulse was observed near the tip of pin-electrode in the artificial channel in spite of the tree propagation.