Kinetic Characteristic of the Dust Particles around the Insulators

2012 ◽  
Vol 455-456 ◽  
pp. 271-277 ◽  
Author(s):  
Jing Wang ◽  
Xi Dong Liang ◽  
Yu Liu
Keyword(s):  
Steady State ◽  
Electric Field ◽  
Drag Force ◽  
Kinetic Characteristic ◽  
Operating Conditions ◽  
Dust Particles ◽  
Field Force ◽  
Polarization Force ◽  
Electric Field Force ◽  
Accumulation Characteristic

Contamination accumulation characteristic of the insulators depends on the kinetic characteristic of the particles moving around the insulators to a great degree. There are many forces acting on the particles due to the combined influence of the electric field, the air fluid field and the gravitational field. The main four forces, which are the polarization force, the electric field force, the steady-state drag force and the gravitational force, were analyzed. Their effects on the moving particles’ trajectories were studied by both experiments and numerical calculation. The results indicate that the polarization force acts where the strength of the electric field changes strongly. Once the particles are charged, the electric field force acts and can drive the particles moving along the electric field lines. When there is a strong wind, the steady-state drag force is dominant and the particles move with the wind. These results can better explain the contamination accumulation characteristic of different insulators under different operating conditions.

scholarly journals Numerical Analysis of Space Charge Behavior and Transient Electric Field under Polarity Reversal of HVDC Extruded Cable

Energies ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2845
Author(s):  
Sun-Jin Kim ◽  
Bang-Wook Lee
Keyword(s):  
Steady State ◽  
Electric Field ◽  
Space Charge ◽  
Field Intensity ◽  
Electric Potential ◽  
Electric Field Intensity ◽  
Dielectric Breakdown ◽  
Operating Conditions ◽  
Polarity Reversal ◽  
Transient Electric Field

The superimposed transient electric field generated by polarity reversal causes severe stress to the high-voltage direct current (HVDC) cable insulation. Especially for polymeric insulation materials, space charge accumulation is prominent, which strengthens local electric field intensity. In order to avoid the risk of dielectric breakdown resulting from an intensified electric field caused by space charge behavior, several numerical analyses have been conducted using the Bipolar Charge Transport (BCT) model. However, these studies have only considered a unidirectional electric field assuming only steady state operating conditions, and there are few works that have analyzed space charge behavior during transient states, especially for the polarity reversal period. In order to analyze the charge behavior under polarity reversal, it is necessary to establish the boundary condition considering the direction and intensity of the field. Therefore, in this paper, we proposed a modified model connecting the steady state to the polarity reversal state, and the transient electric field was investigated depending on the electric potential zero duration. Since space charge behavior is influenced by temperature, different load currents were considered. From the simulation results, it was observed that the capacitive field was dominant on the electric field distribution during the polarity reversal. In addition, the long electric potential zero duration and high load currents could contribute to form a homo-charge at the conductor within the time of polarity reversal, resulting in a noticeable decrease in the maximum electric field intensity.

Research on High Voltage Electromagnetic Electrostatic Spinning Machine Electric Field Analysis

2014 ◽  
Vol 684 ◽  
pp. 259-263
Author(s):  
Yang Tao Yu ◽  
Peng Cheng Zhao ◽  
Xin Wang ◽  
Ye Tian
Keyword(s):  
Electric Field ◽  
High Voltage ◽  
Collection Efficiency ◽  
Field Analysis ◽  
Collection Rate ◽  
Field Force ◽  
Electrostatic Spinning ◽  
Electric Field Analysis ◽  
Electric Field Force ◽  
Electrostatic Mechanism

The main approach to obtain nanomaterial is nanospinning technology at present. Due to the inherent characteristics of nanomaterial itself, which are easily affected by the electric field force effect of spinning. And for the spinning machine nozzle electric field is relatively complex, so nanospinning products at present, is easily affected by the electric field force and dissipated. So, the nanospinning collection efficiency is low. This paper adopts an oval enhanced electrostatic mechanism, method of using additional electric field to improve the balance obtained nanomaterial collection rate. And the construct high voltage electrostatic spinning machine virtual prototype,complete the analysis of the improved method of static electric field. The analysis results indicate that the electric field can effectively improve the collection rate of nanospinning. Through the study of the additional electric field strength further size on the electric field force and the ellipse, can more effectively improve the collection rate of nanospinning products.

scholarly journals The evolution of electron current sheet and formation of secondary islands in guide field reconnection

2011 ◽  
Vol 18 (5) ◽  
pp. 727-733 ◽  
Author(s):  
C. Huang ◽  
Q. Lu ◽  
Z. Yang ◽  
M. Wu ◽  
Q. Dong ◽  
...  
Keyword(s):  
Electric Field ◽  
Current Sheet ◽  
Diffusion Region ◽  
Two Dimensional ◽  
Electron Current ◽  
Particle In Cell ◽  
Field Force ◽  
Guide Field ◽  
Tearing Instability ◽  
Electric Field Force

Abstract. Two-dimensional (2-D) particle-in-cell (PIC) simulations are performed to investigate the evolution of the electron current sheet (ECS) in guide field reconnection. The ECS is formed by electrons accelerated by the inductive electric field in the vicinity of the X line, which is then extended along the x direction due to the imbalance between the electric field force and Ampere force. The tearing instability is unstable when the ECS becomes sufficiently long and thin, and several seed islands are formed in the ECS. These tiny islands may coalesce and form a larger secondary island in the center of the diffusion region.

Sign in / Sign up

Export Citation Format

Share Document