Numerical simulation of transient space charge distribution of DC positive corona discharge under atmospheric pressure air

Abstract

Corona discharges are usually generated at sharp points, edges or on thin wires where the electric field is strongly concentrated. With the rapid development of extra and ultra high-voltage transmission lines, the air corona discharge becomes one of the critical problems associated with high-voltage lines, which can lead to the deterioration of insulation systems, power loss, radio noise. Corona discharge studies have been undertaken for many years, not only because of the scientific interest in the corona mechanism but also because of its practical engineering importance. Transient space charge distribution effect that is one of the important canses in the process of corona discharge, is closely related to the corona discharge mechanism and onset, self-sustaining. In this paper, we present an improved self-consistent, multi-component and two-dimensional plasma hybrid model for simulating the DC positive corona discharge under atmospheric environment. The model is based on the plasma hydrodynamics and the chemical dynamics, and it includes 12 species and 27 reactions. Besides, the photoionization effect is also considered in the proposed model. The simulation and the experiment on bar-plate electrode configuration with an inter-electrode gap of 5.0 mm at 2-5.5 kV are carried out. The discharge voltage-current characteristics and single pulse waveform are in good agreement with the experimental measurements. Based on this model, the electric field distribution, the electron temperature distribution, and the evolution of charged species distribution are investigated in detail. The results show that distributions of electron temperature and electric field have the same patterns, In the process of discharge, electron density is kept at 1019 m-3 or so. O4+ is dominant compared with the other charged heavy species, and O2+ and N2+ play the key role in secondary electron emission: the unmbers of O2- and O are the largest in negative ions and neutral particle respectively, they play a negligible role in discharge process.

Deconstructing plasma fog collection technology: an experimental study on factors impacting collection efficiency

“…This provides direct evidence for the analysis of the reasons for the difference in collection efficiency caused by the power supply polarity as mentioned above. According to previous studies [27,28,29], the most abundant ion produced by positive corona discharge is O 4 + , and the most abundant ion produced by negative corona discharge is O 2 − . The relative atomic mass of O 2 − is less than that of O 4 + .…”

A novel simulation method for positive corona current pulses

“…[18] Considering all of the specific particles and the relevant reactions in the corona discharge will be a great challenge. [19][20][21][22][23] In order to simplify the present investigation, the widely-used hydrodynamic model [4][5][6][7][8][9][10][11]17,[19][20][21][22][23][24][25] which takes the aforementioned basic processes into account is adopted. The governing equations of the hydrodynamic model are…”

Charging and absorption characteristics of small particulates under alternative and electrostatic voltages in an electrostatic precipitator

“…[14] In the corona discharge caused by a high voltage, [15] ionic groups with a high concentration are generated around the electrode. [16] These ionic groups charge the particulates through a physical process. [17] There are two theories explaining particulate charging, i.e., ion collision and ion diffusion.…”