Negative DC corona discharge effects on the ultraviolet photon count in rod to plane air gaps

Abstract

In order to investigate the effects of negative DC corona discharge on ultraviolet (UV) photon count, a corona discharge measurement system based on rod to plane air gaps was established. The variations of positive ion, negative ion, and electron densities were calculated with a fluid model, and the generation process of photons during negative corona discharge was investigated. The differences of photon count and the variation of charged particles between negative and positive corona were also compared. The corona current, Trichel pulses, and corona-generated photons were measured with increasing applied voltage. An approximate parabolic relationship found to exist between the photon count and the corona current, and also an ideal quadratic function was found to exist between the photon count and the frequency of Trichel pulses. These results provide a solid foundation in the application of UV imaging detection of negative DC corona discharge in power equipment.

The role of photoionization in negative corona discharge

“…19 In experiment, semi-quantitative method was employed to study the numerical calculation of photon quantity. [20][21][22] A phenomenon was confirmed that the number of UV photons varies with the applied voltage by experiments. Furthermore, the experimental results about the absorption curve of the photoionization radiation and the characteristic of photoelectron energy distribution were presented from the corona discharge.…”

“…5(g)-(i) that the process of photoionization is more intense in the area of strong ionization process, generation rate of electrons produced by photoionization is much lower than that by electron-impact ionization by more than several orders of magnitude. The generation rate of the electron is around 2.9×10 27 1/(m 3 ·s) at the peak value of the current pulse in strong ionization region and 1×10 22 1/(m 3 ·s) in weak ionization region, and it is not plotted in this manuscript. Therefore, the effect of photoionization in strong ionization region is relatively small.…”

Numerical modeling of negative needle‐to‐plane corona in air under various environmental parameters

“…The function of the ionization coefficient α and the attachment coefficient η in humid air are shown in (7) and (8) [26,27]:…”

Ion-impact secondary emission in negative corona with photoionization

“…As it is, the number of ultraviolet photons varies with the applied voltage and the charged-particle density was investigated and found to be closely related to the photon count from the corona. [12][13][14][15] Furthermore, the absorption curve of the photoionization radiation and the experimental results about the characteristic of photoelectron energy distribution were presented from the corona discharge. 16,17 In order to investigate the role of photoionization in a corona discharge, the simplest simulation model was built by assuming that the photoionization term in the equations has similar properties with uniform background ionization.…”