Preparation of epoxy resin cavity defect sample and research on partial discharge characteristic of three different cavity size

Epoxy resin as an excellent material is widely used in various power equipment. Therefore, for the safe and stable operation of power equipment, it is necessary to study the internal defects of epoxy resin. Although many studies have clarified the preparation method of defect samples and the fundamental phenomenon of deterioration caused by partial discharge (PD) occurring due to defects in inner epoxy, little is known about whether the defect model conforms to the reality. The relation between cavity size and discharge is not clear as well. Hence, this paper provides a realistic and convenient way to generate cavity defect samples by using a pipette gun. Partial discharge measurements with three different sensors have been used to understand the role of cavity size in the process of discharge in the cavity sample. Fast Fourier Transform is also used to study the relation between the frequency of discharge signal and cavity size. The result suggests that the size of cavity does have an effect on the discharge amplitude and the discharge frequency.