Abstract
The series of physical processes contained in the corona layer is the source of space ions formed by the corona discharge of the high-voltage AC line. However, since these physical processes are difficult to calculate accurately and the corona layer thickness is usually small, the corona layer is ignored in the published literature on the corona discharge of the AC line, and the ions are considered to be emitted directly from the conductor surface. In this paper, the distribution area of the charged particles is divided into the corona plasma region and the unipolar drift region. A mathematical physical model of the photoionization and photoemission, which sustain self-sustaining discharge in the positive and negative half-cycle of corona plasma region of the AC conductor in dry air, are established. The influence of the ions generated in the previous cycle is also considered in the numerical simulation process. Finally, a complete microscopic physical model describing the corona discharge of the AC conductor under dry air is established. The validity of the physical model proposed in this paper is demonstrated by comparison with experimental results reported in the literature. Through the numerical simulation of the ion flow field of positive and negative half-cycle and the corona current, the physical process of the corona discharge around the AC line is better understood and analysed. Further positive and negative half-cycle charged particle motion and corona plasma regions were compared and analyzed. This work provides a brand new mathematical physics method for understanding and applying AC corona discharge.
Highlights
High-voltage AC transmission lines have been widely used to meet the growing electricity demand of society
A series of physical processes such as impact ionization, electron attachment, and secondary electron emission included in the corona plasma layer is the source of the formation of space ions in the corona discharge of the high-voltage AC line [9]
The microscopic physics processes of the corona discharge near the AC conductor in dry air, where the distribution region of charged particles is divided into corona plasma layer and unipolar region, is analyzed numerically through a two-dimensional numerical model
Summary
High-voltage AC transmission lines have been widely used to meet the growing electricity demand of society. A series of physical processes such as impact ionization, electron attachment, and secondary electron emission included in the corona plasma layer is the source of the formation of space ions in the corona discharge of the high-voltage AC line [9]. The microscopic physics processes of the corona discharge near the AC conductor in dry air, where the distribution region of charged particles is divided into corona plasma layer and unipolar region, is analyzed numerically through a two-dimensional numerical model. The conductor potential increases quickly to point K, at which point a positive discharge corona is started even through the applied voltage is below the onset level because the presence of a large number of negative ions around the conductor enhances the conductor field. Here ρ is the ions density; θ is the angle between electric field direction generated by ions on the conductor surface and the normal vector, and ε0 is the permittivity of free space; r is the distance between conductor surface and ions; is a bounded convex polygonal domain in R2
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