Study on the Partial Discharge Characteristics of Internal Void Defects under Special-shaped Wave Voltage

During the production, manufacture and transportation of cross-linked polyethylene (XLPE) cable, internal void defects may generate inside the insulation, which will cause partial discharge (PD) affecting the safe and stable operation of XLPE cable. Special-shaped wave voltage has some superiorities in PD detection. The PD characteristics of XLPE insulation samples with internal void defects are investigated under the special-shaped wave voltage in this paper. Firstly, XLPE insulation samples with internal void defects were prepared. Secondly, special-shaped wave voltage was designed and output stably. Thirdly, PD test platform was built, and the tests were performed under both power frequency AC voltage and the special-shaped wave voltage. Finally, the PD characteristics of internal void defects under the above two types of voltages were analyzed. From the comparative analysis of the characteristic parameters of PD under the two voltages, it can be seen that the special-shaped wave voltage has more advantages in PD detection. At the same time, experiments shyow that the special distribution law of the discharge characteristic parameter under the decreasing special-shaped wave voltage is closely related to the accumulation of free electrons and the formation of electron collapses.

I. Introduction

With the continuous optimization and development of the power grid, XLPE cables are widely used for their superior electrical properties [1–2]. However, the defects in the cable insulation will cause PD [3–4]. The degree of deterioration of cable insulation is closely related to the characteristic parameter of PD, so the insulation state of XLPE cables can be detected by PD experiment [5–6].