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High Voltage 2024年第1期9卷 56-65页

作者： Hao Hu zhidong jia Xilin Wang Ruiyang Guan Weinan Fan Simin Luo Tsinghua Shenzhen International Graduate School Tsinghua UniversityShenzhenChina Guangzhou Power Supply China Southern Power Grid Company Ltd.GuangzhouChina

Silicone rubber(SR)is widely used for cable insulation and operates in multi-stress coupling conditions.Its dielectric properties and ageing performance are the essential factors affecting cable operation.In this study,the frequency domain spectroscopy of unaged SR and SR aged under various conditions is measured.The dielectric responses before and after ageing are analysed in depth by the conjoint analysis via multiple complex planes(permittivity,conductivity,and modulus).Typical conductivity and interfacial polarisation properties,as well as property changes resulting from thermal and tensile ageing,are examined.Experimental results show that tensile ageing promotes conductance and interfacial polarisation,while thermal ageing shows the opposite effects.Based on the multi-core model and charge carrier hopping transport model,thermal and tensile ageing mechanisms on the conductance and interfacial polarisation behaviours of SR are demonstrated.Both behaviours exhibit positively correlated changing characteristics,suggesting that the two behaviours may originate from a common process.The carrier transport process,promoted by the tensile effect and slightly suppressed by the thermal effect,is the primary factor and considered an important indicator to evaluate the dielectric properties of SR insulation.

关键词： interfacial rubber insulation

A fabrication method for adaptive dielectric gradient insulating components

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High Voltage 2023年第1期8卷 59-69页

作者： Zikui Shen zhidong jia Yanpeng Hao Zhenyu Xin Xilin Wang School of Electric Power Engineering South China University of TechnologyGuangzhouChina Shenzhen International Graduate School(SIGS) Tsinghua UniversityShenzhenChina

Dielectric gradient components have advantages in electric field mitigation and insulation improvement.In this paper,we propose a fabrication method for adaptive dielectric gradient components using in situ AC electric field,including the mechanism and the corresponding operational procedures for industrial applications.Based on the electric polarisation and self-assembly effect of the filler particles in the liquid matrix,the chainlike structure in the high field strength region is constructed to enhance the local permittivity and mitigate the maximum of the spatial electric field.The dielectric gradient basin insulator is prepared by this method,and its flashover voltage is increased by 12.8%compared with that of a homogeneous dielectric basin insulator,and the improvement is 20.8%when metal particles are present on the surface.The more non-uniform the initial electric field is,the greater the improvement in flashover voltage.This method is expected to promote the industrial application of dielectric gradient insulating components.

关键词： dielectric gradient method

A versatile defect engineering strategy for room-temperature flash sintering

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Journal of Advanced Ceramics 2022年第7期11卷 1172-1178页

作者： Angxuan WU Ziyang YAN Xilin WANG Zhiyang YU Rongxia HUANG Nianping YAN zhidong jia Engineering Laboratory of Power Equipment Reliability in Complicated Coastal Environments Tsinghua Shenzhen International Graduate SchoolTsinghua UniversityShenzhen 518055China State Key Laboratory of Photocatalysis on Energy and Environment College of ChemistryFuzhou UniversityFuzhou 350108China School of Electromechanical Engineering Guangdong University of TechnologyGuangzhou 510006China State Grid jiangxi Electric Power Research Institute Nanchang 330096China

In this study,we reported that flash sintering(FS)could be efficiently triggered at room temperature(25℃)by manipulating the oxygen concentration within ZnO powders via a versatile defect engineering strategy,fully demonstrating a promising method for the repaid prototyping of ceramics.With a low concentration of oxygen defects,FS was only activated at a high onset electric field of~2.7 kV/cm,while arcs appearing on the surfaces of samples.Strikingly,the onset electric field was decreased to<0.51 kV/cm for the activation of FS initiated,which was associated with increased oxygen concentrations coupled with increased electrical conductivity.Thereby,a general room-temperature FS strategy by introducing intrinsic structural defect is suggested for a broad range of ceramics that are prone to form high concentration of point defects.

关键词： flash sintering(FS) oxygen vacancies defect engineering ZnO powders electric discharge

Gas-discharge induced flash sintering of YSZ ceramics at room temperature

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Journal of Advanced Ceramics 2022年第4期11卷 603-614页

作者： Yuchen ZHU Hongyang ZHOU Rongxia HUANG Nianping YAN Xilin WANG Guanghua LIU zhidong jia Engineering Laboratory of Power Equipment Reliability in Complicated Coastal Environments Tsinghua Shenzhen International Graduate SchoolTsinghua UniversityShenzhen 518055China School of Electromechanical Engineering Guangdong University of TechnologyGuangzhou 510006China State Grade jiangxi Electric Power Research Institute Nanchang 330000China State Key Laboratory of New Ceramics and Fine Processing Tsinghua University School of Materials Science and TechnologyTsinghua UniversityBeijing 100084China

This is the first study to conduct the flash sintering of 3 mol%yttria-stabilized zirconia(3YSZ)ceramics at room temperature(25℃)under a strong electric field,larger than 1 kV/cm.At the standard atmospheric pressure(101 kPa),the probability of successful sintering is approximately half of that at low atmospheric pressure,lower than 80 kPa.The success of the proposed flash sintering process was determined based on the high electric arc performance at different atmospheric pressures ranging from 20 to 100 kPa.The 3YSZ samples achieved a maximum relative density of 99.5%with a grain size of~200 nm.The results showed that as the atmospheric pressure decreases,the onset electric field of flash sintering decreases,corresponding to the empirical formula of the flashover voltage.Moreover,flash sintering was found to be triggered by the surface flashover of ceramic samples,and the electric arc on the sample surfaces floated upward before complete flash sintering at overly high pressures,resulting in the failure of flash sintering.This study reveals a new method for the facile preparation of flash-sintered ceramics at room temperature,which will promote the application of flash sintering in the ceramic industry.

关键词： flash sintering yttria-stabilized zirconia(YSZ) room temperature flashover AC field low atmospheric pressure

High‐performance ZnO varistor ceramics prepared by arc‐induced flash sintering with low energy consumption at room temperature

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High Voltage 2022年第2期7卷 222-232页

作者： Angxuan Wu Zhixiang Zhu Xilin Wang Nianping Yan Hongyang Zhou Rongxia Huang Guoming Ma zhidong jia Liming Wang Engineering Laboratory of Power Equipment Reliability in Complicated Coastal Environments Tsinghua Shenzhen International Graduate SchoolTsinghua UniversityShenzhenGuangdongChina State Key Laboratory of Advanced Power Transmission Technology Global Energy Interconnection Research Institute Co.LtdBeijingChina State Grade jiangxi Electric Power Research Institute NanchangChina School of Electromechanical Engineering Guangdong University of TechnologyGuangzhouGuangdongChina State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power UniversityBeijingChina

The development of ultra‐high voltage transmission lines requires a ZnO arrester with excellent electrical response and high voltage gradient.Compared with conventional preparation methods,flash sintering allows fast production of novel high‐performance ZnO varistor ceramics with low energy consumption and controlled grain growth.Herein,ZnO varistor ceramics were prepared using the flash sintering method at an air pressure of 21 kPa for 60 s at 25℃.The results showed that the flash‐sintered samples had fine grains and reduced loss of volatile elements.Moreover,the voltage gradient,leakage current density,and non‐linear coefficient of the flash‐sintered varistor ceramics were significantly improved compared with those of conventionally sintered samples.Owing to the short preparation time and absence of a heating process,the energy consumption of the proposed flash sintering method was significantly reduced to 10%of that by conventional sintering.The proposed method is a promising approach for the preparation of ZnO arresters with excellent electrical properties and serves as an effective method that realises energy saving and emission reduction.

关键词： ceramics varistor preparation

Dielectric barrier discharge-based defect engineering method to assist flash sintering

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Journal of Advanced Ceramics 2023年第5期12卷 1046-1057页

作者： Xinhao Zhao Nianping Yan Yueji Li Zikui Shen Rongxia Huang Chen Xu Xuetong Zhao Xilin Wang Ruobing Zhang zhidong jia Guangdong Engineering Technology Research Center of Power Equipment Reliability in Complicated Coastal Environments Tsinghua Shenzhen International Graduate SchoolTsinghua UniversityShenzhen 518055China State Grid jiangxi Electric Power Research Institute Nanchang 330096China School of Electric Power Engineering South China University of TechnologyGuangzhou 510641China School of Electromechanical Engineering Guangdong University of TechnologyGuangzhou 510006China Institute of Materials China Academy of Engineering PhysicsMianyang 621907China fSchool of Electrical Engineering Chongqing UniversityChongqing 400044China

Oxygen vacancy OV plays an important role in a flash sintering (FS) process. In defect engineering, the methods of creating oxygen vacancy defects include doping, heating, and etching, and all of them often have complex processes or equipment. In this study, we used dielectric barrier discharge (DBD) as a new defect engineering technology to increase oxygen vacancy concentrations of green billets with different ceramics (ZnO, TiO_(2), and 3 mol% yttria-stabilized zirconia (3YSZ)). With an alternating current (AC) power supply of 10 kHz, low-temperature plasma was generated, and a specimen could be treated in different atmospheres. The effect of the DBD treatment was influenced by atmosphere, treatment time, and voltage amplitude of the power supply. After the DBD treatment, the oxygen vacancy defect concentration in ZnO samples increased significantly, and a resistance test showed that conductivity of the samples increased by 2–3 orders of magnitude. Moreover, the onset electric field (E) of ZnO FS decreased from 5.17 to 0.86 kV/cm at room temperature (RT);while in the whole FS, the max power dissipation decreased from 563.17 to 27.94 W. The defect concentration and conductivity of the green billets for TiO_(2) and 3YSZ were also changed by the DBD, and then the FS process was modified. It is a new technology to treat the green billet of ceramics in very short time, applicable to other ceramics, and beneficial to regulate the FS process.

关键词： flash sintering(FS) ZnO dielectric barrier discharge(DBD) oxygen vacancy OV defect engineering

Review of flash sintering with strong electric field

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High Voltage 2022年第1期7卷 1-11页

作者： Hongyang Zhou Xiang Li Yuchen Zhu Jieming Liu Angxuan Wu Guoming Ma Xilin Wang zhidong jia Liming Wang Guangdong Engineering Technology Research Centre of Power Equipment Reliability in Complicated Coastal Environments Tsinghua Shenzhen International Graduate SchoolTsinghua UniversityShenzhenGuangdongChina School of Electrical and Electronic Engineering North China Electric Power UniversityBeijingChina

Flash sintering is a novel field‐assisted sintering technology for ceramics that allows a dramatic reduction in processing time and temperature.Since 2010,when flash sintering was first reported,it has been a focus of research interest in the field of materials science.Recent study results have confirmed that the sintering temperature decreases with the strength of the applied electric field;for some ceramics,the sintering temperature can be lowered even to room temperature.This represents an innovative breakthrough for ceramic sintering at ultra‐low temperatures.However,once the electric field strength in flash sintering is increased,new questions and challenges arise,such as whether or not partial discharge occurs in the green body if under electro‐thermal coupling stress,how to quantitatively analyse the impact of discharge on sintering,and,moreover,whether the sintering mechanism under a strong electric field is consistent with that under a weak electric field.These research questions require knowledge of partial discharge detection,dielectric theory,and other topics that are beyond the scope of materials science.To address this need,this review summarises the work carried out in flash sintering with a strong electric field from the perspective of high voltage and insulation technology.First,the flash sintering process and mechanism are briefly introduced.Then,the published literature on flash sintering with a strong electric field for various ceramic materials is summarised in depth.In addition,experimental phenomena that are observed in flash sintering with a strong electric field,such as flash and blackening,are discussed.Finally,some suggestions for future work are presented.It is anticipated that the knowledge gap between different areas of study can be filled by this review.

关键词： flash knowledge field

Effects of algae contamination on the hydrophobicity of high-voltage composite insulators

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High Voltage 2019年第3期4卷 234-240页

作者： Shifang Yang zhidong jia Xiaogang Ouyang Engineering Laboratory of Power Equipment Reliability in Complicated Coastal Environment Graduate School at ShenzhenTsinghua UniversityTaoyuan Street Nanshan DistrictShenzhen 518055People's Republic of China Department of Electrical Engineering Tsinghua UniversityHaidian DistrictBeijing 100084People's Republic of China

Algae colonisation has been observed on silicone rubber insulators around the world especially in a subtropical climate because the moderate temperature and moisture could aggravate the growth of algae upon silicone rubber material.The surface of these insulators easily forms a water film,and the originally excellent hydrophobicity is decreased or even destroyed.This study explores the regularity of the hydrophobicity changes and the underlying mechanism.Based on the solid layer method,silicone rubber samples were found with algae and inorganics quantitatively,and their contact angles were measured after reservation under different humidity levels.The results showed that although inorganic ash could accelerate the hydrophobic recovery process,algae colonisation decisively decreased the hydrophobicity,especially in moist climates.After an extensive investigation of biological contaminants,it was found that the appearance of algae was independent of inorganics,but algae could accelerate the accumulation of inorganics through water absorptivity and the viscosity of secretions.The water absorption ability of algae was compared with that of inorganic ash and sugar,and their difference was deduced to be due to the environmental adaptability of the algae organisms,which was reflected mainly in a dry climate.The microscopy analysis of bio-contaminants was conducted through SEM.

关键词： algae inorganic rubber

Analytical model for the transient permittivity of uncured TiO_(2) whisker/liquid silicone rubber composites under an AC electric field

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High Voltage 2021年第3期6卷 470-479页

作者： Zikui Shen Zhenyu Xin Xilin Wang Xinyu Wei zhidong jia Engineering Laboratory of Power Equipment Reliability in Complicated Coastal Environment Shenzhen International Graduate SchoolTsinghua UniversityShenzhenChina

The electric field grading of dielectric permittivity gradient devices is an effective way of enhancing their insulation properties.The in situ electric field‐driven as-sembly is an advanced method for the fabrication of insulation devices with adaptive permittivity gradients;however,there is no theoretical guidance for design.In this study,an analytical model with a time constant is developed to determine the transient permittivity of uncured composites under an applied AC electric field.This model is based on optical image and dielectric permittivity monitoring,which avoids the direct processing of complex electrodynamics.For a composite with given components,the increased filler content and electric field strength can accelerate the transient process.Compared with the finite element method based on differential equations,this statistical model is simple but efficient,and can be applied to any low‐viscosity uncured composites,which may contain multiple fillers.More importantly,when a voltage is applied to an uncured composite insulating device,the proposed model can be used to analyse the spatiotemporal permittivity characteristics of this device and optimise its permittivity gradient for electric field grading.

关键词： composites permittivity transient

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基于激光诱导击穿光谱的硅橡胶胶含量检测

高电压技术 2024年第4期50卷 1684-1693页

作者：何永琪邓禹田亮王希林贾志东清华大学深圳国际研究生院深圳复杂滨海环境电力装备可靠性工程实验室深圳518055 中国电力科学研究院有限公司北京100192 西藏羊八井高海拔电气安全与电磁环境国家野外科学观测研究站西藏851517

硅橡胶胶含量不仅能够反映复合绝缘子的老化状态,而且可以反映其产品质量。测定胶含量对于复合绝缘子运维以及入网前的质量监测具有重要意义,但目前缺乏一种高效、准确的硅橡胶复合绝缘子胶含量现场原位检测手段。为此基于激光诱导击穿... 详细信息

硅橡胶胶含量不仅能够反映复合绝缘子的老化状态,而且可以反映其产品质量。测定胶含量对于复合绝缘子运维以及入网前的质量监测具有重要意义,但目前缺乏一种高效、准确的硅橡胶复合绝缘子胶含量现场原位检测手段。为此基于激光诱导击穿光谱技术,探究了硅橡胶胶含量的光谱表征手段。以11种不同配方的高温硫化硅橡胶样品为研究对象,分别建立了Al、Si原子谱线强度,等离子体温度以及Si离子原子谱线强度比与硅橡胶胶含量之间的线性定标模型,其中等离子体温度的拟合优度最高为0.9114,SiⅠ390.55 nm谱线强度的拟合优度最低为0.4857。最终,选取了AlⅠ394.40 nm、AlⅠ396.15 nm、SiⅠ390.55 nm谱线强度作为自变量,建立了胶含量的多元线性定标模型,预测结果拟合优度可达0.9884。

关键词：硅橡胶胶含量激光诱导击穿光谱多元线性回归定量分析