Diagnosing the operational status of High-voltage circuit breakers(HVCBs)is crucial for ensuring the safe and stable operation of the grid.Mechanical characteristic parameters are effective indicators for evaluating t...Diagnosing the operational status of High-voltage circuit breakers(HVCBs)is crucial for ensuring the safe and stable operation of the grid.Mechanical characteristic parameters are effective indicators for evaluating the performance of HVCBs.Recent studies have shown that the actions of the springs and cams in HVCBs can be used to detect the operational status of the mechanical mechanisms,which occur extremely quickly,usually in the speed of m/ms.In this paper,dynamic vision sensing technology was employed to rapidly and dynamically capture the movements of the springs and cam of the HPL245B1 HVCB.The data volume of a single experiment is less than 100 MB,whereas the data collected by a high-speed camera at the same frame rate exceeds 1 GB.Action data streams of the springs and cam were obtained and images were reconstructed from the event streams.The Lucas-Kanade optical flow algorithm and the normalised cross-correlation algorithm are applied to calculate the parameters of spring deformation characteristics and cam rotation characteristics for mechanical feature detection of HVCBs.This is the first attempt to utilize brain-inspired hardware technology for the status monitoring of electrical equipment.The advantages of dynamic vision sensing technology,such as high dynamic range,low data transmission,and low energy con-sumption,also offer significant benefits for air discharge monitoring and status moni-toring of electrical equipment.展开更多
Room-temperature flash sintering(FS)for ceramics is a highly efficient and energy-saving new ceramic sintering technique.Addressing the current challenges in room-temperature flash sintering research,such as small pro...Room-temperature flash sintering(FS)for ceramics is a highly efficient and energy-saving new ceramic sintering technique.Addressing the current challenges in room-temperature flash sintering research,such as small product sizes,shape limitations,and high power requirements,limits their real application in the FS industry.In particular,for dog bone shape and small size,which are usually smaller than 10 mm,no records of sizes larger than 20 mm have been reported.In this study,a novel flash sintering device based on a composite layered carbon electrode structure was developed to conduct large-diameter sample flash sintering at room temperature(RT)in an air atmosphere under a direct current(DC)voltage below 10o V.Specifically,room-temperatureflash sintering was achievedfor Zn0 ceramic disks with diameters of 40.0 mm and thicknesses of 1.80 mm,achieving a maximum relative density of 96.02%.Furthermore,room-temperature flash sintering was achieved for ZnO varistor ceramic disks with a diameter of 40.0 mm and a thickness of 1.93 mm,reaching a maximum relative density of 99.27%,a maximum voltage gradient of 330.5 V·mm^(-1),and the highest nonlinearity coefficient(a)of 23.0.Room-temperature flash sintering was also achieved for 3 mol%yttrium-doped zirconia(3YSZ)ceramic disks,achieving a maximum relative density of 98.48%.The proposed flash sintering device and corresponding process demonstrate broad applicability for the ceramics industry.展开更多
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(...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.展开更多
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 compl...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.展开更多
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...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.展开更多
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 d...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.展开更多
For the first time,the flash sintering(FS)of high-purity alumina at room temperature,which was previously considered unachievable due to its low electrical conductivity,was conducted herein.The electrical arc originat...For the first time,the flash sintering(FS)of high-purity alumina at room temperature,which was previously considered unachievable due to its low electrical conductivity,was conducted herein.The electrical arc originating from surface flashover was harnessed to induce FS at room temperature and low air pressure.The successful FS of high-purity alumina was realized at 60 kPa under the arc constraint,resulting in a notable relative density of the alumina sample of 98.7%.The electric–thermal coupling between the arc and high-purity alumina sample during the arc-induced FS process was analyzed via the finite element simulation method.The results revealed the thermal and electrical effects of the arc on the sample,which ultimately enhance the electrical conductivity of the alumina sample.The formation of a conductive channel on the sample surface,a result of increased electrical conductivity,was the pivotal factor in achieving FS in high-purity alumina at room temperature.The arc constraint technique can be applied to numerous materials,such as ionic conductors,semiconductors,and even insulators,under room-temperature and low-air-pressure conditions.展开更多
基金National Natural Science Foundation of China,Grant/Award Numbers:52077118,62411560155Guangdong Basic and Applied Basic Research Foundation,Grant/Award Number:2024A1515012597。
文摘Diagnosing the operational status of High-voltage circuit breakers(HVCBs)is crucial for ensuring the safe and stable operation of the grid.Mechanical characteristic parameters are effective indicators for evaluating the performance of HVCBs.Recent studies have shown that the actions of the springs and cams in HVCBs can be used to detect the operational status of the mechanical mechanisms,which occur extremely quickly,usually in the speed of m/ms.In this paper,dynamic vision sensing technology was employed to rapidly and dynamically capture the movements of the springs and cam of the HPL245B1 HVCB.The data volume of a single experiment is less than 100 MB,whereas the data collected by a high-speed camera at the same frame rate exceeds 1 GB.Action data streams of the springs and cam were obtained and images were reconstructed from the event streams.The Lucas-Kanade optical flow algorithm and the normalised cross-correlation algorithm are applied to calculate the parameters of spring deformation characteristics and cam rotation characteristics for mechanical feature detection of HVCBs.This is the first attempt to utilize brain-inspired hardware technology for the status monitoring of electrical equipment.The advantages of dynamic vision sensing technology,such as high dynamic range,low data transmission,and low energy con-sumption,also offer significant benefits for air discharge monitoring and status moni-toring of electrical equipment.
基金supported by the National Natural Science Foundation of China(No.52077118)the Open Fund of the State Key Laboratory of High-Efficiency and High-Quality Conversion for Electric Power(No.2024KF006)+2 种基金the Guangdong Basic and Applied Basic Research Foundation(No.2024A1515012597)the State Grid Jiangxi Electric Power Company Science and Technology Project(No.52182025000H)the Jiangxi Key Research and Development Program(No.20243BBG71028).
文摘Room-temperature flash sintering(FS)for ceramics is a highly efficient and energy-saving new ceramic sintering technique.Addressing the current challenges in room-temperature flash sintering research,such as small product sizes,shape limitations,and high power requirements,limits their real application in the FS industry.In particular,for dog bone shape and small size,which are usually smaller than 10 mm,no records of sizes larger than 20 mm have been reported.In this study,a novel flash sintering device based on a composite layered carbon electrode structure was developed to conduct large-diameter sample flash sintering at room temperature(RT)in an air atmosphere under a direct current(DC)voltage below 10o V.Specifically,room-temperatureflash sintering was achievedfor Zn0 ceramic disks with diameters of 40.0 mm and thicknesses of 1.80 mm,achieving a maximum relative density of 96.02%.Furthermore,room-temperature flash sintering was achieved for ZnO varistor ceramic disks with a diameter of 40.0 mm and a thickness of 1.93 mm,reaching a maximum relative density of 99.27%,a maximum voltage gradient of 330.5 V·mm^(-1),and the highest nonlinearity coefficient(a)of 23.0.Room-temperature flash sintering was also achieved for 3 mol%yttrium-doped zirconia(3YSZ)ceramic disks,achieving a maximum relative density of 98.48%.The proposed flash sintering device and corresponding process demonstrate broad applicability for the ceramics industry.
基金This work was supported by the National Natural Science Foundation of China(No.52077118)the Guangdong Basic and Applied Basic Research Foundation(No.2021A1515011778)the State Key Laboratory of New Ceramics and Fine Processing Tsinghua University(No.KFZD201903).
文摘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.
基金supported by the National Natural Science Foundation of China(No.52077118)the Guangdong Basic and Applied Basic Research Foundation(No.2021A1515011778)State Key Laboratory of Power System Operation and Control,Tsinghua University(No.SKLD22KM01).
文摘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.
基金supported by the National Natural Science Foundation of China(52077118)the Guangdong Basic and Applied Basic Research Foundation(2021A1515011778)+1 种基金the State Key Laboratory of New Ceramic and Fine Processing Tsinghua University(KFZD201903)the State Grid Cor-poration of China Headquarters Technology Project(5200‐201,940,081A‐0‐0‐00).
文摘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.
基金This work was supported by the National Natural Science Foundation of China(No.52077118)the Guangdong Basic and Applied Basic Research Foundation(No.2021A1515011778)the State Key Laboratory of New Ceramics and Fine Processing Tsinghua University(No.KFZD201903).
文摘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.
基金This work was supported by the National Natural Science Foundation of China(52077118)Guangdong Basic and Applied Basic Research Foundation(2021A1515011778)Key Laboratory of Engineering Dielectrics and Its Application(Harbin University of Science and Technology),Ministry of Education(KFM202204).
文摘For the first time,the flash sintering(FS)of high-purity alumina at room temperature,which was previously considered unachievable due to its low electrical conductivity,was conducted herein.The electrical arc originating from surface flashover was harnessed to induce FS at room temperature and low air pressure.The successful FS of high-purity alumina was realized at 60 kPa under the arc constraint,resulting in a notable relative density of the alumina sample of 98.7%.The electric–thermal coupling between the arc and high-purity alumina sample during the arc-induced FS process was analyzed via the finite element simulation method.The results revealed the thermal and electrical effects of the arc on the sample,which ultimately enhance the electrical conductivity of the alumina sample.The formation of a conductive channel on the sample surface,a result of increased electrical conductivity,was the pivotal factor in achieving FS in high-purity alumina at room temperature.The arc constraint technique can be applied to numerous materials,such as ionic conductors,semiconductors,and even insulators,under room-temperature and low-air-pressure conditions.
