The Electric Field Characteristics Analysis of Converter Transformer Considering Anisotropic

2012 ◽  
Vol 215-216 ◽  
pp. 1308-1311
Author(s):  
You Hua Gao ◽  
Xiao Mo Hou ◽  
Hong Gao ◽  
Xiao Ming Liu
Keyword(s):  
Electric Field ◽  
Polarity Reversal ◽  
Insulation Material ◽  
Before And After ◽  
Characteristics Analysis ◽  
Calculation Results ◽  
Paper Insulation ◽  
Variation Rule ◽  
Transient Electric Field ◽  
Numerical Calculation Result

Simulation and analysis of the converter transformer valve side’s transient electric field by finite element method is proposed. The electric field of converter transformer valve side’s is calculated under polarity reversal condition, the maximum value of the electric field intensity of insulating materials and the potential distribution of the before and after first polarity reversal are given, obtaining the electric field distribution characteristics of the oil-paper insulation material in the case of isotropic and anisotropic before and after the first polarity reversal, and made a comparison. The numerical calculation result of the converter transformer valve side’s electric field is also given, and the comparison of the calculation results in the case of isotropic and anisotropic, for before and after the first polarity reversal is analyzed, obtaining the variation rule of the converter transformer valve side’s electric field and the variable factors which affected the distribution of the electric field.

scholarly journals Effect of Temperature on Space Charge Distribution of Oil–Paper Insulation under DC and Polarity Reversal Voltage

Energies ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 2271 ◽  
Author(s):  
Qingguo Chen ◽  
Jinfeng Zhang ◽  
Minghe Chi ◽  
Peng Tan ◽  
Wenxin Sun
Keyword(s):  
Electric Field ◽  
Space Charge ◽  
Electric Field Distribution ◽  
Operating Conditions ◽  
Polarity Reversal ◽  
Effect Of Temperature ◽  
Slow Decay ◽  
Voltage Polarity ◽  
Field Distortion ◽  
Paper Insulation

The electric field distortion caused by space charge is an important factor affecting the operation reliability of oil–paper insulation in a converter transformer. To study the accumulation and decay characteristics of the space charge within oil-impregnated pressboard under DC and polarity reversal voltage, and consider the possible operating conditions of the converter transformer, the space charge behavior of oil-impregnated pressboard was measured by the pulsed electro-acoustic (PEA) method in the temperature range from −20 °C to 60 °C. The effect of temperature on the accumulation and decay characteristics of space charge is also analyzed. The space charge accumulated within the pressboard at low temperature is mainly homocharge injected by the electrode, while heterocharge formed by ion dissociation counteracts some of the homocharge at high temperature. Thus, the space charge of pressboard first increases, then decreases, with an increase in temperature. However, slow decay of the space charge causes severe distortion of the electric field distribution in the pressboard during voltage polarity reversal.

Analysis of Transient Electric Field and Charge Density of Converter Transformer Under Polarity Reversal Voltage

2012 ◽  
Vol 48 (2) ◽  
pp. 275-278 ◽  
Author(s):  
Gang Liu ◽  
Lin Li ◽  
Feng Ji ◽  
Wenping Li ◽  
Youliang Sun ◽  
...  
Keyword(s):  
Electric Field ◽  
Charge Density ◽  
Polarity Reversal ◽  
Transient Electric Field

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.

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