Electric Field Measurement in the Process of Partial Discharge Using Electric Field Induced Second Harmonic Generation

The electric field is critically important in the process of a partial discharge (PD), as it affects many physical parameters such as electron temperature and ion drift velocity. To explore the PD mechanism, the electric field induced second harmonic generation (E-FISH) method, which is an accurate measurement of the transient electric field intensity, is adopted, and one specific electrode configuration is designed to reduce the dispersion of the measurement results. In the sample, an aluminum oxide ceramic sheet is pasted on the metal plane electrode, and a copper foil is pasted on the sheet center, ensuring a uniform electric field distribution between the two copper foils during the PD process no matter where the PD occurs in the channel. The measurement results show that the electric field variation of a PD process among the three measurements is almost the same, with less dispersion in the discharge initiation time, the discharge capacity, and the breakdown electric field.