Space Charge Behavior of Oil-Impregnated Paper Insulation Aging at AC-DC Combined Voltages

The space charge behaviors of oil-paper insulation affect the stability and security of oil- filled converter transformers of traditional and new energies. This paper presents the results of the electrical aging of oil-impregnated paper under AC-DC combined voltages by the pulsed electro- acoustic technique. Data mining and feature extractions were performed on the influence of electrical aging on charge dynamics based on the experiment results in the first stage. Characteristic parameters such as total charge injection and apparent charge mobility were calculated. The influences of electrical aging on the trap energy distribution of an oil-paper insulation system were analyzed and discussed. Longer electrical aging time would increase the depth and energy density of charge trap, which decelerates the apparent charge mobility and increases the probability of hot electron formation. This mechanism would accelerate damage to the cellulose and the formation of discharge channels, enhance the acceleration of the electric field distortion, and shorten insulation lifetime under AC-DC combined voltages.

[1]  P. Subburaj,et al.  Partial Discharge Signal Denoising using Adaptive Translation Invariant Wavelet Transform-Online Measurement , 2014 .

[2]  G. Chen,et al.  Effect of polyethylene interface on space charge formation , 2004, IEEE Transactions on Dielectrics and Electrical Insulation.

[3]  S. Swingler,et al.  Electric field in polymeric cable due to space charge accumulation under DC and temperature gradient , 2011, IEEE Transactions on Dielectrics and Electrical Insulation.

[4]  S. Grzybowski,et al.  Electrical breakdown properties of oil-paper insulation under AC-DC combined voltages , 2010, 2010 IEEE International Power Modulator and High Voltage Conference.

[5]  R. Ciobanu,et al.  PEA measurements upon cellulose materials submitted to gamma radiation , 2004, Proceedings of the 2004 IEEE International Conference on Solid Dielectrics, 2004. ICSD 2004..

[6]  Lijun Yang,et al.  Research on the feature extraction of DC space charge behavior of oil-paper insulation , 2011 .

[7]  Ming Dong,et al.  Investigation on dielectric response characteristics of thermally aged insulating pressboard in vacuum and oil-impregnated ambient , 2010, IEEE Transactions on Dielectrics and Electrical Insulation.

[8]  A. Bulinski,et al.  Space charge development and breakdown in XLPE under DC field , 2004 .

[9]  B. T. Ooi,et al.  Optimal Acquisition and Aggregation of Offshore Wind Power by Multiterminal Voltage-Source HVdc , 2002, IEEE Power Engineering Review.

[10]  Hai-Bao Mu,et al.  Effects of paper-aged state on space charge characteristics in oil-impregnated paper insulation , 2012, IEEE Transactions on Dielectrics and Electrical Insulation.

[11]  Deming Liu.  THEORY OF ISOTHERMAL CHARGE AND DIRECT DETERMINATION OF TRAP DISTRIBUTIONS IN SOLID DIELECTRICS , 1992 .

[12]  K. C. Kao,et al.  New theory of electrical discharge and breakdown in low‐mobility condensed insulators , 1984 .

[13]  Ey Goo Kang,et al.  A Study on Characteristic Improvement of IGBT with P-floating Layer , 2014 .

[14]  Zhiqiang Xu,et al.  Space charge measurement and analysis in low density polyethylene films , 2009 .

[15]  Gian Carlo Montanari,et al.  Quantities extracted from space-charge measurements as markers for insulation aging , 2003 .

[16]  R. Liao,et al.  Space charge behavior in multi-layer oil-paper insulation under different DC voltages and temperatures , 2010, IEEE Transactions on Dielectrics and Electrical Insulation.

[17]  M. Fu,et al.  ac aging and space-charge characteristics in low-density polyethylene polymeric insulation , 2005 .

[18]  M. Bergkvist,et al.  Moisture and space charge in oil-impregnated pressboard under HVDC , 1998, ICSD'98. Proceedings of the 1998 IEEE 6th International Conference on Conduction and Breakdown in Solid Dielectrics (Cat. No.98CH36132).

[19]  G. Montanari,et al.  Dielectric material properties investigated through space charge measurements , 2004, IEEE Transactions on Dielectrics and Electrical Insulation.

[20]  Tu De-min,et al.  Measuring Energy Distribution of Surface Trap in Polymer Insulation by PEA Method , 2009 .

[21]  Lijun Yang,et al.  Influence of moisture on space charge dynamics in multilayer oil-paper insulation , 2012, IEEE Transactions on Dielectrics and Electrical Insulation.

[22]  Tu De,et al.  STUDY ON THE ACTION MECHANISM OF THE FREE RADICAL SCAVENGER WITH ISOTHERMAL-CURRENT DECAY METHOD—AN EXPERIMENTAL VERIFICATION OF TRAP THEORY FOR ELECTRICAL AGING IN POLYMER , 2000 .

[23]  Gian Montanari,et al.  Bringing an insulation to failure: The role of space charge , 2010, 2010 Annual Report Conference on Electrical Insulation and Dielectic Phenomena.

[24]  G. Montanari,et al.  A space-charge based method for the estimation of apparent mobility and trap depth as markers for insulation degradation-theoretical basis and experimental validation , 2003 .