Space Plasma Distribution Effect of Short-Circuit Arc on Generation of Secondary Arc

Abstract

Secondary arc is more severe in the ultra-high voltage (UHV) power grid. However, the mechanism for the generation process of secondary arc at the extinction moment of a short-circuit arc is not yet clear. It is of great theoretical significance and technological application value to study the generation mechanism and dynamic physical characteristics of secondary arc, and further to develop effective suppression technology. In this article, an arc numerical simulation model based on the coefficient partial differential equations combining with classical drift-diffusion model was established, and the implementation method based on the finite element software COMSOL (COMSOL Multiphysics 5.2a, COMSOL Inc., Stockholm, Sweden) was given. Then, the transient analysis method was applied to simulate the generation, diffusion and dissipation phenomena of the short-circuit arc strike, and further to explore the electric field, microscopic particle spatial distribution and reaction process during the arc discharge process. The simulation results show that the development of short-circuit arc mainly includes two processes: corona discharge and arc discharge, of which the former has a very short duration and the latter is caused by short-circuit. During the discharge process, the electron density first increases and then decreases, which is different from the general characteristics of streamer discharge. Although the concentration distribution curve of the positive ions and negative ions has the same trend, there are subtle differences. The diffusion effect of space ions in the initial discharge stage is almost zero, while radial diffusion direction in the peak discharge stage and axial direction in the late discharge stage. The electric field intensity in space has an S-shaped upward trend during discharge. The time relationship of the ion source generated by the neutralization reaction and by the short-circuit arc discharge are basically the same, and the rate of neutralization reaction is lowest near the electrode. When the ionic reaction is approaching the end of the simulation, the ionic concentration is higher than the initial level, which proves that the space ionic concentration is increased due to the short-circuit discharge, and providing the necessary environmental conditions for the subsequent generation of the secondary arc.

Parametric characterization of arcs in semi-sealed splitter plate DC circuit breakers

“…The flow characteristics of the plasma during the opening process are computed using the Navier-Stokes equations and energy equation. The temperature and velocity distribution of the plasma in the semi-sealed splitter plate DC circuit breaker are depicted in figure 2 The ion mobility of the arc is set to 2 × 10 −4 m 2 (V•s) −1 based on [23][24][25][26]. The diameter of the probe is 0.6 mm.…”

Numerical Modeling of Space–Time Characteristics of Plasma Initialization in a Secondary Arc

“…For the purposes of this study, an ignition line was added to the simulation model, and the emission particle source (electron g e2 , positive ion g p2 , negative ion g n2 ) was set on the ignition line to simulate the high-charge-density arc channel generated by the short-circuit combustion. The particle sources were established with the following Gaussian pulse functions ( Figure 3) [22]:…”