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Space charge characteristics and dielectric properties of PANI/PP-g-MAH/PP ternary composite

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High Voltage 2025年第1期10卷 178-185页

作者： Guochang Li Tianzhen Liu Zhenlu Gu Xiaolong Chen Beibei Sun Yuanwei Zhu Shengtao Li Yanhui Wei College of Materials science and Engineering Qingdao University of Science and TechnologyQingdaoChina State Key Laboratory of Electrical Insulation and Power Equipment Xi'an Jiaotong UniversityXi'anChina

Space charge accumulation in polypropylene materials for direct current capacitor will accelerate the ageing of the materials,resulting in the degradation of their insulation ***,it will also affect the dielectric properties of the capacitor in a long *** this paper,a ternary composite of polyaniline(PANI)/maleic anhydride functionalised PP(PP-g-MAH)/polypropylene(PP)based on the PANI@dopamine(PDA)coating structure is constructed from two perspectives of PP matrix grafting and PANI nano *** method takes advantage of the high permittivity and good compatibility of PANI to improve the relative dielectric constant of the composite while introducing deep traps inside the composite to inhibit space charge accumulation *** experimental results show that with the increase in PANI content,the maximum relative permittivity can be increased by 62%.The addition of the appropriate amount of PANI can effectively inhibit the space charge *** relative dielectric constant of the composite decreases significantly due to the heteropolar space *** relative dielectric constant of the modified polyaniline composites decreased *** reduction rate decreased from 38%before modification to 12%after *** work has certain guiding significance for solving space charge problem of direct current capacitor.

关键词： composite composites dielectric

Properties of diffuse and volume discharges that are important for their applications

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High Voltage 2025年第1期10卷 126-136页

作者： Victor Tarasenko Alexei Panchenko Dmitry Beloplotov Mikhail Lomaev Dmitry Sorokin Cheng Zhang Institute of High Current Electronics Siberian BranchRussian Academy of ScienceTomskRussia Beijing International S&T Cooperation Base for Plasma science and Energy Conversion Institute of Electrical EngineeringChinese Academy of SciencesBeijingChina

Diffuse and volume discharges are currently used widely in various *** work compares the properties of diffuse and volume discharges,as well as considers the conditions for their formation at high *** main attention is paid to a diffuse discharge(DD).It has been shown that the ignition of a diffuse discharges is preceded by the development of a wide *** the case of a volume discharge,the streamers usually have a small diameter and an ionisation waves emerging from it passes into the spark leader with subsequent discharge *** are images and emission spectra of diffuse discharges in air and nitrogen in the *** has been confirmed that a diffuse discharges initiated by a nanosecond voltage pulse in a point-to-plane gaps has a uniform effect on the surface of a flat *** was found that thin tracks of luminous particles are observed against the background of the DD plasma *** are asso-ciated with sputtering of the pointed electrode material due to the large field enhance-ment on the macro-and microinhomogeneities.

关键词： luminous subsequent initiated

Photodetector array for measuring the spatial-temporal distribution characteristics of electric field in oil-pressboard insulation based on the Kerr electro-optic effect

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High Voltage 2025年第1期10卷 95-105页

作者： Chunjia Gao Bo Qi Chengrong Li Yukung Zheng State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power UniversityBeijingChina

Accurate measurement and effective analysis of the space electric field and charge characteristics within the oil-pressboard insulation structure of converter transformer are essential for achieving precise insulation structure ***,most electric field measurement methods relying on the Kerr electro-optical effect are limited to single-point *** the complexity of converter transformer insulation struc-tures,including their large scale and the use of various materials,existing technologies and findings struggle to provide comprehensive electric field observations within the oil-pressboard *** leveraging the Kerr electro-optic effect,a high-precision 32-unit photodetector array has been developed to achieve regional measurements of spatial-temporal electric field in oil-pressboard *** array boasts a measure-ment spatial resolution of 1.4 mm^(2)and a sensitivity of 0.15 kV/mm,ensuring mea-surement accuracy exceeding 96.50%.Through practical measurements of the spatial electric field distribution within the oil-pressboard insulation under direct current voltage,the non-uniform distribution of the electric field is effectively captured in ***,the maximum deviation in field strength at different positions within the transformer oil can reach 18.5%.Moreover,as the applied voltage increases,the un-evenness coefficient of the field strength gradually rises,peaking at 1.19,which signifies a progressive expansion in the area affected by electric field *** conducting tests to assess the dispersion of volume resistivity in samples from various positions within large sheets of pressboard,the variation in volume resistivity of materials is posited as one of the contributing factors to the non-uniform distribution of electric field within the *** detailed accomplishments aim to provide essential technical and theoretical support for optimising insulation structure design of converter transformers.

关键词： insulation distribution field

Stress analysis and structural optimisation of insulating rods under dynamic and static loads

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High Voltage 2025年第1期10卷 116-125页

作者： Haifeng Jin Lijun Jin Department of Control science and Engineering Tongji UniversityShanghaiChina

This study aims to provide a theoretical basis for the fatigue characteristics and structural optimisation of insulating rods to enhance their reliability and lifespan in practical *** paper uses COMSOL to complete the stress analysis of insulating rods under dynamic and static loads based on the finite element *** correctness of the model is verified based on the elastic-plastic *** simulation results show that under the same load,the stress concentration area is more affected by the dynamic load,and the stress concentration position is highly consistent with the fracture position of the rod in the *** verifies the impact on the insulating rods at different speeds and static load *** shows that,in cases where the allowable stress is exceeded,as the number of operations increases,the fatigue characteristics will greatly affect the service life of the insulation ***,the fatigue analysis and structural optimisation of the insulating rod were completed,providing important reference values for the long-term stable operation of ultra-high voltage circuit breakers.

关键词： fatigue structural dynamic

Electrohydraulic effect of microsecond pulsed discharge in transformer oils

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High Voltage 2025年第1期10卷 137-145页

作者： Hang Wang Cheng Zhang Zhuofei Wang Shuai Zhang Kaihang Guo Tao Shao Beijing International S&T Cooperation Base for Plasma science and Energy Conversion Institute of Electrical EngineeringChinese Academy of SciencesBeijingChina University of Chinese Academy of sciences BeijingChina

The physical process of microsecond pulsed discharge in transformer oil is the foun-dation for studying the initial mechanics of faults in ultra-high voltage ***,the microsecond-scale electrohydraulic effect in transformer oil has not been investigated *** this paper,the shock wave and bubble generated by microsecond pulsed discharge in transformer oil between needle-needle electrodes are studied using a Schlieren system with a high-speed *** results show that the discharge channel in the 0.1 mm oil gap forms in 9.50μs when the streamer and the first shock wave are *** bubble between electrodes expands in the subsequent 218.50μ***,the bubble collapses when the second shock wave is *** velocities of the first and the second shock wave are 1388.16 and 1465.46 m/s,*** the gap distance increase,all the breakdown voltage,the discharge energy,and the ratio of the mechanical energy to total energy increase,the breakdown current,the acceleration of the container wall,and the velocity of the shock wave *** can be concluded that the first shock wave is generated by the streamer of microsecond pulsed discharge and the second shock wave is induced by the rapid density change due to the bubble collapsing.

关键词： bubble effect acceleration

Effect of nanostructured SiO_(2)on charge capture performance and electrical ageing life of PP nanocomposites

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High Voltage 2025年第1期10卷 186-196页

作者： Junguo Gao Liwei Liu Guangwei Zhang Tingtai Lee Uwe Schachtely Hitoshi Kobayashi Key Laboratory of Engineering Dielectrics and Its Application Ministry of EducationHarbin University of Science and TechnologyHarbinChina State Key Laboratory of Electrical Insulation and Power Equipment Xi'an Jiaotong UniversityXi'anChina Evonik Specialty Chemicals Co. Ltd.ShanghaiChina Evonik Operations GmbH Hanau-WolfgangGermany Evonik(SEA)Pte Ltd SingaporeSingapore

To guarantee the reliability of high-performance and environmentally friendly novel polypropylene(PP)for use as the primary insulation in cables,an assessment of the electrical ageing life of SiO_(2)/PP composite materials was carried out using a stepstress accelerated ageing test based on the inverse power *** study involved an analysis of microstructural characteristics and performance testing to investigate the bonding between the SiO_(2)under different surface treatment methods and ***,the impact of SiO_(2)on charge capture performance in PP insulation was analysed through polarisation–depolarisation current *** results show that silica with long alkane chains and amino groups grafted on the surface has good compatibility with PP insulating layers,which can increase the trap energy level of captured electrons and thus reduce the damage of high-energy electrons to the ***_(2)increased the life index of the PP insulating layer by 19.95%,which contributed to the improvement of the electrical ageing life of the PP insulating layer.

关键词： life performance electrical

The relationship between power of arc discharge in transformer oil and peak value of the shock wave

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High Voltage 2025年第1期10卷 157-166页

作者： Guangjin Zhang Tianyu Han Tao Wen Yi Zhao Weijiang Chen Qiaogen Zhang Jinzhong Li Ke Wang State Key Laboratory of Electrical Insulation and Power Equipment Xi'an Jiaotong UniversityXi'anChina School of Electrical Engineering and Automation Hefei University of TechnologyHefeiChina State Grid Corporation of china BeijingChina china Electrical Power Research Institute BeijingChina

Since 2018,there have been seven incidents of explosions and fires in ultra-high voltage transformers in china,which are caused by internal arc discharge in transformer *** pressure measurement experiments have been conducted to explore the laws of discharge ***,differences in experimental conditions,discharge energy,and current peak values have led to discrepancies in the discharge power and pressure laws in these ***,it is crucial to investigate the relationship between arc discharge power and pressure peak in transformer *** arc discharge test platform was established to measure pressure waveforms based on the RLC ***,a shadow optical path observation system was implemented to record the development process of discharge arc,bubble pulsation,and shock *** study reveals the positive relationship between the average power and the peak value of the shock wave;the former refers to the breakdown and expansion stage of the arc channel,and the latter is generated by the discharge,***,the pressure generation mechanism of arc discharge in transformer oil and the relationship between arc discharge power and peak value of discharge pressure are revealed.

关键词： power value wave

Check dams on china's Loess Plateau:An overview

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River

River 2025年第1期4卷 1-20页

作者： Zuyu Chen Shujing Chen Penghai Yin Shu Yu Naichang Zhang State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin China Institute of Water Resources and Hydropower ResearchBeijingChina College of Civil and Transportation Engineering Weifang UniverstiyWeifangChina Powerchina Northwest Engineering Corporation Limited Xi'anChina

Check dams are widely constructed on china's Loess Plateau,which had a total number of 58,776 by the end of *** achievements in check dam construction have been gained regarding the economic and environmental *** study reviews the remarkable benefits of check dams on the land reclamation and environmental improvement on the Loess Plateau,and sediment reduction entering the Yellow ***,the flood incidents on check dams have been frequently reported for the past decades,which has attracted more attention in the context of climate change and extreme rainfall events *** in the flood migration techniques achieved by the research group led by the first author have been highlighted to migrate the breach risk of check dams due to ***“family tree method”has been proposed to determine the survival status and critical rainfall threshold of each check dam in the complicated dam *** updated dam breach flood evaluation framework and the corresponding numerical algorithm(i.e.,DB-IWHR)have been ***,innovative types of water-release facilities for check dams,including geobag stepped spillway and prestressed concrete cylinder pipe in the underlying conduit,have been proposed and ***,the perspectives concerning the check dam construction on the Loess Plateau have been put forward.

关键词： check dams china's Loess Plateau DB-IWHR “family tree method” geobag stepped spillway

Research on influence of double energy absorptions on dynamic volt-ampere characteristics of metal oxide varistors

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High Voltage 2025年第1期10卷 78-87页

作者： Chen Long Yifei Wu Yi Wu Mingzhe Rong Yu Xiao Yunfan Bai State Key Laboratory of Electrical Insulation and Power Equipment Xi'an Jiaotong UniversityXi'anShaanxiChina

Metal oxide varistors(MOVs)are extensively employed in DC circuit breakers(DCCBs)to suppress overvoltage,dissipate energy and build up voltage after *** their widespread use,the performance of MOVs under short-time,double energy ab-sorption conditions is not well understood,posing a challenge to their application in open-close-open(OCO)operations of *** this paper,a MOV double energy absorption test platform is established to investigate the deviation in volt-ampere *** Fréchet distance is proposed as the criterion for assessing the similarity of MOV dynamic volt-ampere characteristics,and the influencing factors are *** is observed that a 15%increase in the absorption of rated energy may result in roughly 20-unit rise in the Fréchet ***,the deviation in volt-ampere characteristics during the second pulse is found to be independent of the time interval,affirming that the OCO operation within 300 ms constitutes an adiabatic *** excursion of the volt-ampere characteristics is dominated by the energy and remains unaffected by the peak current of the initial *** findings lay the foundation for the subsequent MOV dynamic characteristic balance test and model modification.

关键词： double dynamic energy