Space charge and insulation properties of nano-Al2O3-modified oil-impregnated paper used for HVDC convertor transformer

Zhang, Jinfeng; Chen, Qingguo; Chi, Minghe; Yang, Hongda; Liu, Heqian

doi:10.1007/s10854-020-05117-5

Cited by 3 publications

(2 citation statements)

References 30 publications

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“…As it is a core component of the HVDC transmission system, the safe operation of the converter transformer is crucial to the overall performance of the system (Chen et al, 2018;Cheng et al, 2019). While the converter transformer mainly uses oil-paper insulation as internal insulation (Zhang et al, 2021), this insulation may develop defects during its operation such that the local field strength becomes…”

Section: Introductionmentioning

confidence: 99%

Investigating the growth of carbon traces in cardboard in oil-paper insulation

Zhang

Pan²,

Dong³

et al. 2023

Front. Energy Res.

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A large amount of contaminants are collected on the cardboard surface of the valve-side bushing outlet of a converter transformer that has been operating for a long period, and can cause the performance of the oil–paper insulation to degrade. The analysis of their energy spectrum has shown that these contaminants contain free carbon. To investigate causes of the formation of these carbon traces, the authors of this study analyze their law of growth on the surface of the insulating paper in the presence of pure insulating oil and insulating oil containing carbon particles. We examined the influence of carbon tracks of different lengths on the breakdown voltage along the surface of the oil–paper insulation. The results showed that carbonization on the surface of the insulating paper generated carbon traces in pure insulating oil and eventually led to the formation of conductive channels. Moreover, carbon traces were generated by carbon particles deposited on the surface of the insulating paper in insulating oil containing carbon particles. The carbon traces grew from the high-voltage electrode to the ground electrode along the direction of the electric field in both types of oils. The formation of the conductive channel through the poles of the paper in insulating oil containing carbon particles required a lower voltage and a shorter discharge time than that in pure insulating oil. As the concentration of the carbon particles increased, the rate of growth of carbon traces on the surface of the insulating paper increased such that the oil–paper insulation failed earlier than otherwise. Long carbon traces were formed on the surface of the insulating paper in case of a high concentration of carbon particles under the DC pre-pressure mode, and this led to a reduction in the breakdown voltage along the surface of the oil–paper insulation.

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Section: Introductionmentioning

confidence: 99%

Investigating the growth of carbon traces in cardboard in oil-paper insulation

Zhang

Pan²,

Dong³

et al. 2023

Front. Energy Res.

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“…These interface charges play a dominate role in the performance of the insulation system. [16,21] For example, interface charges at the oil/paper, [22][23][24][25][26][27] and cross-linked polyethylene (XLPE)/ethylene propylene diene monomer (EPDM) structure, [6,8,28] cause the electric field enhancement, indicating the degradation of the power transformers and cables in high voltage direct current (HVDC) power applications. [16,29,30] Electrode/polymer interfaces exhibit charge injection, extraction [31,32] and electroluminescence, [33,34] leading to undesired electric field changes and discharge.…”

mentioning

confidence: 99%

Interface Charge Characteristics in Polymer Dielectric Contacts: Analysis of Acoustic Approach and Probe Microscopy

Wang

et al. 2023

Adv Materials Inter

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Interfaces are essential components in polymer contact systems, which widely exist in electronic devices and power equipment. Interface charge originating from the mismatch of the electronic structure in interfaces is one of the key issues to modify the device performance due to its multifunctional migration and accumulation behaviors. Hence, the detection and analysis of the interface charge characteristics are of great importance to deeply understand the polymer contact system in various devices. This paper presents an overview of recent research progress in the interface charge properties at dielectric interfaces. Based on the theoretical analysis of the MWS polarization and electronic localized states, two typical approaches of discussing the interface charges from micrometer to millimeter are mainly studied. Acoustic method is prevalent in detecting the space charge in various dielectrics. However, owing to its limited resolution (several µm), it is difficult to clarify the charge distributions at the interface with a micro‐scale. Probe microscopy presents a promising technique due to its flexible surface potential detection at a submicron scale. The challenges and prospects of acoustic and probe microscopy methods are discussed in this paper. The advanced techniques of interface charges can promote the development of new energy electronic devices.

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Enhanced Aramid/Al2O3 interfacial properties by PDDA modification for the preparation of composite insulating paper

Lü

Song

et al. 2022

Res Chem Intermed

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For further improve the electrical insulation properties of meta-aramid paper(PMIA), polydimethyldiallyl ammonium chloride (PDDA) was used for the modi cation of nano-Al 2 O 3 in this work. The modi ed products were characterized by means of transmission electron microscopy (TEM), Fourier transform infrared spectrometer (FTIR) and liquid Zeta potential. The original and PDDA modi ed nano-Al 2 O 3 was doped into the aramid ber composite, and the effects of PDDA and ller mass fraction on several properties such as electrical conductivity, breakdown strength and surface charge dissipation rate of insulating paper were studied. Finally, the interfacial properties of the composites were investigated using molecular dynamics (MD). The results showed that PDDA was successfully coated on the surface of nano-Al 2 O 3 , and its surface potential was changed from negative to positive, which could improve the interface characteristics between ller and matrix and enhance the dielectric strength of aramid paper. Besides, saturation effect of PDDA modi cation was observed, and when the amount of PDDA was 10% and the content of modi ed nano-Al 2 O 3 was 3%, the breakdown strength of aramid paper was increased by 20%, and the volume conductivity was decreased by 68%. The simulation result revealed that PDDA could improve the insulation performance of aramid paper by reducing the interfacial binding energy between aramid and ller.

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Space charge and insulation properties of nano-Al2O3-modified oil-impregnated paper used for HVDC convertor transformer

Cited by 3 publications

References 30 publications

Investigating the growth of carbon traces in cardboard in oil-paper insulation

Investigating the growth of carbon traces in cardboard in oil-paper insulation

Interface Charge Characteristics in Polymer Dielectric Contacts: Analysis of Acoustic Approach and Probe Microscopy

Enhanced Aramid/Al2O3 interfacial properties by PDDA modification for the preparation of composite insulating paper

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