Space Charge Modulated Electrical Breakdown of Oil Impregnated Paper Insulation Subjected to AC-DC Combined Voltages
1
State Key Laboratory of Electrical Insulation and Power Equipment, Xi’an Jiaotong University, Xi’an 710049, China
2
School of Electronics and Computer Science University of Southampton, Southampton SO17 1BJ, UK
*
Author to whom correspondence should be addressed.
Energies 2018, 11(6), 1547; https://doi.org/10.3390/en11061547
Received: 14 May 2018 / Revised: 29 May 2018 / Accepted: 31 May 2018 / Published: 13 June 2018
(This article belongs to the Section Electrical Power and Energy System)
Based on the existing acknowledgment that space charge modulates AC and DC breakdown of insulating materials, this investigation promotes the related investigation into the situations of more complex electrical stress, i.e., AC-DC combined voltages. Experimentally, the AC-DC breakdown characteristics of oil impregnated paper insulation were systematically investigated. The effects of pre-applied voltage waveform, AC component ratio, and sample thickness on AC-DC breakdown characteristics were analyzed. After that, based on an improved bipolar charge transport model, the space charge profiles and the space charge induced electric field distortion during AC-DC breakdown were numerically simulated to explain the differences in breakdown characteristics between the pre-applied AC and pre-applied DC methods under AC-DC combined voltages. It is concluded that large amounts of homo-charges are accumulated during AC-DC breakdown, which results in significantly distorted inner electric field, leading to variations of breakdown characteristics of oil impregnated paper insulation. Therefore, space charges under AC-DC combined voltages must be considered in the design of converter transformers. In addition, this investigation could provide supporting breakdown data for insulation design of converter transformers and could promote better understanding on the breakdown mechanism of insulating materials subjected to AC-DC combined voltages.
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MDPI and ACS Style
Zhu, Y.; Li, S.; Min, D.; Li, S.; Cui, H.; Chen, G. Space Charge Modulated Electrical Breakdown of Oil Impregnated Paper Insulation Subjected to AC-DC Combined Voltages. Energies 2018, 11, 1547. https://doi.org/10.3390/en11061547
AMA Style
Zhu Y, Li S, Min D, Li S, Cui H, Chen G. Space Charge Modulated Electrical Breakdown of Oil Impregnated Paper Insulation Subjected to AC-DC Combined Voltages. Energies. 2018; 11(6):1547. https://doi.org/10.3390/en11061547
Chicago/Turabian StyleZhu, Yuanwei; Li, Shengtao; Min, Daomin; Li, Shijun; Cui, Huize; Chen, George. 2018. "Space Charge Modulated Electrical Breakdown of Oil Impregnated Paper Insulation Subjected to AC-DC Combined Voltages" Energies 11, no. 6: 1547. https://doi.org/10.3390/en11061547
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