Measurement of spatial total electric field under DC corona discharge in wire-plate electrode based on electric-field-induced second harmonic effect

As a valid non-intrusive electric field (E-field) measurement technique, the E-field measurement method based on the electric-field-induced second harmonic (E-FISH) effect has demonstrated its advantages of high spatial and temporal resolution in various scenarios in recent years. In this paper, an E-field measurement platform based on the E-FISH effect is established, and the spatial total E-field of DC corona discharge of the wire-plate electrode is measured by using the E-field calibration method, which has accounted for the edge effects of the parallel plate electrodes. The accuracy of the calibration coefficient was verified by comparing the calibrated E-field without corona discharge with the electrostatic field simulated using the finite element method. In the presence of corona discharge, the wire surface E-field strength exhibits a linear decrease with the increasing corona current. Besides, the influence of different parameters on the surface E-field strength is also systematically investigated. At identical corona current levels, the surface E-field strength during positive corona discharge is measurably lower than that under negative polarity conditions. Notably, for a given increase in corona current density, the resultant reduction in surface E-field strength is independent of the wire diameter. Moreover, as the absolute humidity increases, the rate of decrease in the surface E-field strength accelerates, while the total E-field above the plate electrode intensifies.