Metal particles near insulators are the main cause of insulation failure of gas-insulated switchgear (GIS), which seriously affects the stable operation of the power grid. In this article, the experimental platform of dust movement adsorption by ac GIS was built. The effects of applied voltage level, dust material, quantity, and size on their movement behavior were studied. The special luminescence phenomenon induced by the movement of metal dust was analyzed. The results show that small size and large amount of metal dust have a greater influence on the insulation performance of the basin insulator. In the process of its movement, it is easy to form a series channel of multiple particles, which seriously distorts the electric field near the GIS basin insulator. In addition, when the charge polarity of the jumping particles is different, charge transfer will occur between the particles, and a “luminescence phenomenon” will occur. The luminescence phenomenon may directly cause the insulator to flashover along the surface, which seriously affects its insulation performance. At the same time, the “luminescence phenomenon” increases the temperature in the laboratory, creating conditions for the reaction of metal dust with oxidizing gases. This work can provide data support and a theoretical basis for the study of metal dust discharge in GIS, and the special phenomenon of “dust luminescence” found can provide new ideas for improving the reliability of GIS.
{"title":"Movement and Discharge Characteristics of Metal Dust in GIS Under AC Voltage: Focus on a Special Luminescence Phenomenon","authors":"Zicheng Tian;Xiaolong Li;Xinbo Sun;Jin He;Yunqi Xing","doi":"10.1109/TDEI.2025.3573993","DOIUrl":"https://doi.org/10.1109/TDEI.2025.3573993","url":null,"abstract":"Metal particles near insulators are the main cause of insulation failure of gas-insulated switchgear (GIS), which seriously affects the stable operation of the power grid. In this article, the experimental platform of dust movement adsorption by ac GIS was built. The effects of applied voltage level, dust material, quantity, and size on their movement behavior were studied. The special luminescence phenomenon induced by the movement of metal dust was analyzed. The results show that small size and large amount of metal dust have a greater influence on the insulation performance of the basin insulator. In the process of its movement, it is easy to form a series channel of multiple particles, which seriously distorts the electric field near the GIS basin insulator. In addition, when the charge polarity of the jumping particles is different, charge transfer will occur between the particles, and a “luminescence phenomenon” will occur. The luminescence phenomenon may directly cause the insulator to flashover along the surface, which seriously affects its insulation performance. At the same time, the “luminescence phenomenon” increases the temperature in the laboratory, creating conditions for the reaction of metal dust with oxidizing gases. This work can provide data support and a theoretical basis for the study of metal dust discharge in GIS, and the special phenomenon of “dust luminescence” found can provide new ideas for improving the reliability of GIS.","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"33 1","pages":"723-731"},"PeriodicalIF":3.1,"publicationDate":"2025-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146102974","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-22DOI: 10.1109/TDEI.2025.3572891
Yuhuai Wang;Jin Li;Hui Ni;Hucheng Liang;Hang Yao;Boxue Du
Surface conductivity graded insulators (SCGIs) present promising application for compact dc-gas-insulated switchgear (GIS), where the lifting behavior of particles and the occurrence of abnormal surface discharge are highly dependent on the electric field distribution. In this part, an iterative method for optimizing the surface conductivity distribution of the SCGI is proposed. Surface electric field inhomogeneity coefficients were used to assess the optimization of electric field. After optimization, the inhomogeneity coefficient of tangential electric field on the insulator surface is decreased from 3.79 to 2.07. The electric field strength around the insulator’s grounded shell is significantly reduced. The optimized surface conductivity distribution presented obvious zoning characteristics. To simplify the manufacturing process of SCGI, the optimal surface conductivity distribution was discretized. Surface fluorination technology is utilized to manufacture SCGIs. A graded distribution of surface conductivity along the SCGI is achieved, by adjusting the fluorination time in various areas, enhancing the surface insulating properties of insulators and inhibiting the activity of metal particles around insulators in dc-GIS.
{"title":"Surface Conductivity Graded Insulator for DC-GIS—Part I: Design and Fabrication","authors":"Yuhuai Wang;Jin Li;Hui Ni;Hucheng Liang;Hang Yao;Boxue Du","doi":"10.1109/TDEI.2025.3572891","DOIUrl":"https://doi.org/10.1109/TDEI.2025.3572891","url":null,"abstract":"Surface conductivity graded insulators (SCGIs) present promising application for compact dc-gas-insulated switchgear (GIS), where the lifting behavior of particles and the occurrence of abnormal surface discharge are highly dependent on the electric field distribution. In this part, an iterative method for optimizing the surface conductivity distribution of the SCGI is proposed. Surface electric field inhomogeneity coefficients were used to assess the optimization of electric field. After optimization, the inhomogeneity coefficient of tangential electric field on the insulator surface is decreased from 3.79 to 2.07. The electric field strength around the insulator’s grounded shell is significantly reduced. The optimized surface conductivity distribution presented obvious zoning characteristics. To simplify the manufacturing process of SCGI, the optimal surface conductivity distribution was discretized. Surface fluorination technology is utilized to manufacture SCGIs. A graded distribution of surface conductivity along the SCGI is achieved, by adjusting the fluorination time in various areas, enhancing the surface insulating properties of insulators and inhibiting the activity of metal particles around insulators in dc-GIS.","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"33 1","pages":"707-714"},"PeriodicalIF":3.1,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146102979","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-22DOI: 10.1109/TDEI.2025.3572896
Yuhuai Wang;Jin Li;Jianan Dong;Hang Yao;Hucheng Liang;Boxue Du
To investigate the effect of surface conductivity gradient design on the electric field regulation of insulators, the surface charging characteristics and metal particle lifting activity of surface conductivity graded insulators (SCGIs) were measured under different operating conditions. The platform was designed to replicate the typical conditions of dc-gas insulated metal enclosed switchgear (GIS), including dc operating conditions, dc polarity reversal, and ac and dc superposition. The surface charge distribution of various types of insulators and the lifting voltage of metal particles near the insulators were tested. The results indicate that the SCGI can regulate the surface charge distribution, significantly reduce electric field distortion around the insulator’s grounding shell, and inhibit the lifting behavior of particles under dc conditions. In addition, the surface-conducting graded insulators demonstrate optimal charge modulation and suppression of metal particle activity under dc polarity reversal and ac-dc superposition conditions, effectively enhancing insulation performance under complex operating conditions. The study may serve as a valuable reference for the optimal design of dc GIS insulators.
{"title":"Surface Conductivity Graded Insulator for DC-GIS—Part II: Surface Charging and Metal Particle Lifting Behaviors","authors":"Yuhuai Wang;Jin Li;Jianan Dong;Hang Yao;Hucheng Liang;Boxue Du","doi":"10.1109/TDEI.2025.3572896","DOIUrl":"https://doi.org/10.1109/TDEI.2025.3572896","url":null,"abstract":"To investigate the effect of surface conductivity gradient design on the electric field regulation of insulators, the surface charging characteristics and metal particle lifting activity of surface conductivity graded insulators (SCGIs) were measured under different operating conditions. The platform was designed to replicate the typical conditions of dc-gas insulated metal enclosed switchgear (GIS), including dc operating conditions, dc polarity reversal, and ac and dc superposition. The surface charge distribution of various types of insulators and the lifting voltage of metal particles near the insulators were tested. The results indicate that the SCGI can regulate the surface charge distribution, significantly reduce electric field distortion around the insulator’s grounding shell, and inhibit the lifting behavior of particles under dc conditions. In addition, the surface-conducting graded insulators demonstrate optimal charge modulation and suppression of metal particle activity under dc polarity reversal and ac-dc superposition conditions, effectively enhancing insulation performance under complex operating conditions. The study may serve as a valuable reference for the optimal design of dc GIS insulators.","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"33 1","pages":"715-722"},"PeriodicalIF":3.1,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146102968","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
To reduce the potential threat of water in electrical equipment, it is crucial to study the mechanisms of water accumulation in insulating oil under electrical manipulation. This study established an oil-water mixture model using molecular dynamics (MDs) simulations to quantitatively explore the dynamic evolution of water clusters under different electric fields. Key findings indicate that under a direct current (dc) electric field, polar water molecules align with the field. At dc electric field strengths (${E} _{text {DC}}$ ) below 0.50 V/nm, interactions between water molecules strengthen, leading to tighter aggregation and increased nucleation and growth rates. As ${E} _{text {DC}}$ increases, polarization intensifies, enhancing oil-water interactions, restricting water mobility, and inhibiting new nucleation. Existing droplets stretch and grow rapidly, with reduced internal density, causing structural instability. Under an alternating current (ac) electric field, water molecule orientation adjusts periodically. At electric field amplitudes $text {(}{E}_{{0}}text {)}$ below 0.50 V/nm, weak polarization and depolarization effects reduce water molecule migration. However, stronger intermolecular attraction tightens molecular aggregation, leading to increased collision frequency, which subsequently enhances nucleation and growth rates. As a result, the formed water clusters tend to hover near the center of the electric field. As ${E}_{{0}}$ exceeds 0.50 V/nm, stronger periodic polarization enhances aggregation, resulting in more vigorous motion and the formation of larger, more stable droplets. Relatively speaking, the ac field shows stronger dynamic regulation, accelerating water molecule aggregation and nucleation, particularly at ${E}_{{0}}=2.00$ V/nm. This study provides key insights into the dynamic behavior of water in electrical equipment.
{"title":"Electrically Manipulated Water Accumulation in Insulating Oil: Insights From Molecular Dynamics Simulations","authors":"Shaoqi Wang;Qiaogen Zhang;Jiahe Zhu;Tonglei Wang;Zhicheng Wu","doi":"10.1109/TDEI.2025.3571384","DOIUrl":"https://doi.org/10.1109/TDEI.2025.3571384","url":null,"abstract":"To reduce the potential threat of water in electrical equipment, it is crucial to study the mechanisms of water accumulation in insulating oil under electrical manipulation. This study established an oil-water mixture model using molecular dynamics (MDs) simulations to quantitatively explore the dynamic evolution of water clusters under different electric fields. Key findings indicate that under a direct current (dc) electric field, polar water molecules align with the field. At dc electric field strengths (<inline-formula> <tex-math>${E} _{text {DC}}$ </tex-math></inline-formula>) below 0.50 V/nm, interactions between water molecules strengthen, leading to tighter aggregation and increased nucleation and growth rates. As <inline-formula> <tex-math>${E} _{text {DC}}$ </tex-math></inline-formula> increases, polarization intensifies, enhancing oil-water interactions, restricting water mobility, and inhibiting new nucleation. Existing droplets stretch and grow rapidly, with reduced internal density, causing structural instability. Under an alternating current (ac) electric field, water molecule orientation adjusts periodically. At electric field amplitudes <inline-formula> <tex-math>$text {(}{E}_{{0}}text {)}$ </tex-math></inline-formula> below 0.50 V/nm, weak polarization and depolarization effects reduce water molecule migration. However, stronger intermolecular attraction tightens molecular aggregation, leading to increased collision frequency, which subsequently enhances nucleation and growth rates. As a result, the formed water clusters tend to hover near the center of the electric field. As <inline-formula> <tex-math>${E}_{{0}}$ </tex-math></inline-formula> exceeds 0.50 V/nm, stronger periodic polarization enhances aggregation, resulting in more vigorous motion and the formation of larger, more stable droplets. Relatively speaking, the ac field shows stronger dynamic regulation, accelerating water molecule aggregation and nucleation, particularly at <inline-formula> <tex-math>${E}_{{0}}=2.00$ </tex-math></inline-formula> V/nm. This study provides key insights into the dynamic behavior of water in electrical equipment.","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"32 5","pages":"2722-2729"},"PeriodicalIF":3.1,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145189973","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-20DOI: 10.1109/TDEI.2025.3571687
Aleksey A. Petrov;Sergey Yu. Savinov;Ravil Kh. Amirov;Igor S. Samoylov
Nanosecond discharge has been studied in non-boiling liquid nitrogen. The discharge is initiated in the gap in the central conductor of a coaxial waveguide with an impedance of $50~Omega $ . The gap varied within 10–$100~mu $ m. The dielectric of the waveguide and the discharge medium is non-boiling liquid nitrogen at atmospheric pressure and temperature 65 K. The amplitude of the voltage pulse is +/–12–25 kV, the duration is 7 ns, the voltage rise time is 150 ps. It is found that the leading edge of the discharge current is less than 80 ps. According to estimates, the electron ionization rate $nu _{i}$ is more than $7.5cdot 10^{{10}}$ ${mathrm {s}}^{-{1}}$ and the ionization rate constant ${k} _{i}$ is more than $4.2cdot 10^{-{12}}$ cm3${mathrm {s}}^{-{1}}$ in non-boiling liquid nitrogen at 65 K. A passing electromagnetic coupling wave with amplitude about 10 kV and duration 150 ps is detected behind the discharge gap in the waveguide. The formation of electromagnetic coupling wave is numerically demonstrated. The dependence of the discharge delay time on the electric field in the gap is measured. The formation of $20~mu $ m size erosion craters is found at the surface of the electrodes demonstrating the possible role of the micro-explosive processes in the discharge mechanism.
{"title":"Nanosecond Discharge in Non-Boiling Liquid Nitrogen","authors":"Aleksey A. Petrov;Sergey Yu. Savinov;Ravil Kh. Amirov;Igor S. Samoylov","doi":"10.1109/TDEI.2025.3571687","DOIUrl":"https://doi.org/10.1109/TDEI.2025.3571687","url":null,"abstract":"Nanosecond discharge has been studied in non-boiling liquid nitrogen. The discharge is initiated in the gap in the central conductor of a coaxial waveguide with an impedance of <inline-formula> <tex-math>$50~Omega $ </tex-math></inline-formula>. The gap varied within 10–<inline-formula> <tex-math>$100~mu $ </tex-math></inline-formula>m. The dielectric of the waveguide and the discharge medium is non-boiling liquid nitrogen at atmospheric pressure and temperature 65 K. The amplitude of the voltage pulse is +/–12–25 kV, the duration is 7 ns, the voltage rise time is 150 ps. It is found that the leading edge of the discharge current is less than 80 ps. According to estimates, the electron ionization rate <inline-formula> <tex-math>$nu _{i}$ </tex-math></inline-formula> is more than <inline-formula> <tex-math>$7.5cdot 10^{{10}}$ </tex-math></inline-formula> <inline-formula> <tex-math>${mathrm {s}}^{-{1}}$ </tex-math></inline-formula> and the ionization rate constant <inline-formula> <tex-math>${k} _{i}$ </tex-math></inline-formula> is more than <inline-formula> <tex-math>$4.2cdot 10^{-{12}}$ </tex-math></inline-formula> cm3<inline-formula> <tex-math>${mathrm {s}}^{-{1}}$ </tex-math></inline-formula> in non-boiling liquid nitrogen at 65 K. A passing electromagnetic coupling wave with amplitude about 10 kV and duration 150 ps is detected behind the discharge gap in the waveguide. The formation of electromagnetic coupling wave is numerically demonstrated. The dependence of the discharge delay time on the electric field in the gap is measured. The formation of <inline-formula> <tex-math>$20~mu $ </tex-math></inline-formula>m size erosion craters is found at the surface of the electrodes demonstrating the possible role of the micro-explosive processes in the discharge mechanism.","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"32 5","pages":"2783-2787"},"PeriodicalIF":3.1,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145189966","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-14DOI: 10.1109/TDEI.2025.3551678
T. Jayasree;Issouf Fofana;Esperanza Mariela Rodriguez-Celis;Patrick Picher;S. Brettschneider
The tremendous demand for electricity requires higher operating voltages, which in turn impose great stress on the transformer insulation system. Condition-based maintenance and liquid decontamination are activities for assessing the risks and extending the service life of such systems. It is therefore important to explore the reclamation of the new biodegradable liquids. It is known that adsorbent-based reclamation is a prominent approach to treating insulating liquids. The present article provides the results of an experimental study on the reclamation of two low-pour-point synthetic ester fluids and a typical synthetic ester liquid using magnesium silicate-based adsorbents. The experimental results also include mineral insulating oil for a baseline reference. All four of these liquids were subjected to accelerated aging under open beaker conditions in the presence of cellulose. The aged liquids were then regenerated by pressure and gravity percolations with two magnesium silicate-based adsorbents. Physicochemical and electrical characterizations were conducted on both the feed and the filtrate. It is inferred that magnesium silicate-based adsorbents have some potential for the reclamation of synthetic esters by removing the polar compounds that evolved with the liquid’s service life.
{"title":"Reclamation of Synthetic Ester Dielectric Liquids by Pressure and Gravity Percolation Methods","authors":"T. Jayasree;Issouf Fofana;Esperanza Mariela Rodriguez-Celis;Patrick Picher;S. Brettschneider","doi":"10.1109/TDEI.2025.3551678","DOIUrl":"https://doi.org/10.1109/TDEI.2025.3551678","url":null,"abstract":"The tremendous demand for electricity requires higher operating voltages, which in turn impose great stress on the transformer insulation system. Condition-based maintenance and liquid decontamination are activities for assessing the risks and extending the service life of such systems. It is therefore important to explore the reclamation of the new biodegradable liquids. It is known that adsorbent-based reclamation is a prominent approach to treating insulating liquids. The present article provides the results of an experimental study on the reclamation of two low-pour-point synthetic ester fluids and a typical synthetic ester liquid using magnesium silicate-based adsorbents. The experimental results also include mineral insulating oil for a baseline reference. All four of these liquids were subjected to accelerated aging under open beaker conditions in the presence of cellulose. The aged liquids were then regenerated by pressure and gravity percolations with two magnesium silicate-based adsorbents. Physicochemical and electrical characterizations were conducted on both the feed and the filtrate. It is inferred that magnesium silicate-based adsorbents have some potential for the reclamation of synthetic esters by removing the polar compounds that evolved with the liquid’s service life.","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"32 5","pages":"3012-3018"},"PeriodicalIF":3.1,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145189968","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-13DOI: 10.1109/TDEI.2025.3550912
Zijian Wang;Yiming Lei;Fei Yan;Lin Yang;Zichen Wang;Yanfeng Ma
Surface flashover significantly affects the insulation performance of metallized film capacitors (MFCs), and the clear edge is the main area where the surface flashover occurs. An experimental platform is built to study ac surface flashover at the clear edge of metallized polypropylene film capacitors. The effects of interlayer pressure, experiment temperature, clear edge width, square resistance, absolute humidity, and voltage frequency on the ac surface flashover of metallized films are investigated. The results indicate that the surface flashover voltage and field strength increase with the increase of interlayer pressure in the range of 100–800 kPa and decrease with the increase of experiment temperature in the range of $30~^{circ }$ C–$90~^{circ }$ C; the flashover field strength decreases by 44% and gradually tends to be stable as the clear edge width varies from 0.5 to 2.5 mm; the surface flashover voltage and field strength increase by 78% as the square resistance increases from 7.5 to $50~Omega $ /$Box $ ; the surface flashover voltage increases with the increase of absolute humidity in the range of 4–16 g/m3; the surface flashover voltage and field strength decrease by 4% with the increase of voltage frequency in the range of 50–400 Hz. In the design and manufacture of MFCs, the interlayer pressure of outer films should be appropriately increased; the design of the clear edge width of MFCs with different square resistance, operating temperatures, and voltage frequencies can be selected according to the experimental results of this article. Since the moisture will be removed by heating and vacuumizing in the capacitor manufacturing process, the design of the clear edge width could refer to the experimental results under low humidity.
{"title":"AC Surface Flashover Characteristics at the Clear Edge of Metallized Polypropylene Film Capacitors","authors":"Zijian Wang;Yiming Lei;Fei Yan;Lin Yang;Zichen Wang;Yanfeng Ma","doi":"10.1109/TDEI.2025.3550912","DOIUrl":"https://doi.org/10.1109/TDEI.2025.3550912","url":null,"abstract":"Surface flashover significantly affects the insulation performance of metallized film capacitors (MFCs), and the clear edge is the main area where the surface flashover occurs. An experimental platform is built to study ac surface flashover at the clear edge of metallized polypropylene film capacitors. The effects of interlayer pressure, experiment temperature, clear edge width, square resistance, absolute humidity, and voltage frequency on the ac surface flashover of metallized films are investigated. The results indicate that the surface flashover voltage and field strength increase with the increase of interlayer pressure in the range of 100–800 kPa and decrease with the increase of experiment temperature in the range of <inline-formula> <tex-math>$30~^{circ }$ </tex-math></inline-formula>C–<inline-formula> <tex-math>$90~^{circ }$ </tex-math></inline-formula>C; the flashover field strength decreases by 44% and gradually tends to be stable as the clear edge width varies from 0.5 to 2.5 mm; the surface flashover voltage and field strength increase by 78% as the square resistance increases from 7.5 to <inline-formula> <tex-math>$50~Omega $ </tex-math></inline-formula>/<inline-formula> <tex-math>$Box $ </tex-math></inline-formula>; the surface flashover voltage increases with the increase of absolute humidity in the range of 4–16 g/m3; the surface flashover voltage and field strength decrease by 4% with the increase of voltage frequency in the range of 50–400 Hz. In the design and manufacture of MFCs, the interlayer pressure of outer films should be appropriately increased; the design of the clear edge width of MFCs with different square resistance, operating temperatures, and voltage frequencies can be selected according to the experimental results of this article. Since the moisture will be removed by heating and vacuumizing in the capacitor manufacturing process, the design of the clear edge width could refer to the experimental results under low humidity.","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"32 3","pages":"1305-1313"},"PeriodicalIF":2.9,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144213676","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The dissolved gas analysis (DGA) technology is a key method for monitoring large oil-immersed transformers. However, the large size, complex structure, and extended gas diffusion paths of high-capacity transformers make the diffusion characteristics of fault-generated gases within the transformer unclear, which limits the detection accuracy of DGA technology. This article investigates the diffusion characteristics of dissolved gases in a ±400 kV converter transformer under various fault types and analyzes the temporal changes in gas concentration at different monitoring points during the diffusion process. The results show that oil flow velocity is the primary factor influencing the diffusion of dissolved gases in the transformer. Although the concentration of fault gases does not affect the diffusion path of dissolved gases in the transformer, it does influence the diffusion rate. Moreover, the oil flow circulation at the turret on the ac side of the converter transformer is slow and directional, which impedes the diffusion of dissolved gases in the transformer oil, thereby hindering timely fault detection. The results of this study offer significant insights for the installation of dissolved gas monitoring devices in field converter transformers and the determination of the optimal monitoring cycle interval.
{"title":"Investigation on the Diffusion Characteristics of Dissolved Gas in an Actual 400 kV Converter Transformer—Effects of Fault Types","authors":"Jia Tao;Xiongying Duan;Peng Yu;Minfu Liao;Zhengqin Zhou;Hao Zhan","doi":"10.1109/TDEI.2025.3549714","DOIUrl":"https://doi.org/10.1109/TDEI.2025.3549714","url":null,"abstract":"The dissolved gas analysis (DGA) technology is a key method for monitoring large oil-immersed transformers. However, the large size, complex structure, and extended gas diffusion paths of high-capacity transformers make the diffusion characteristics of fault-generated gases within the transformer unclear, which limits the detection accuracy of DGA technology. This article investigates the diffusion characteristics of dissolved gases in a ±400 kV converter transformer under various fault types and analyzes the temporal changes in gas concentration at different monitoring points during the diffusion process. The results show that oil flow velocity is the primary factor influencing the diffusion of dissolved gases in the transformer. Although the concentration of fault gases does not affect the diffusion path of dissolved gases in the transformer, it does influence the diffusion rate. Moreover, the oil flow circulation at the turret on the ac side of the converter transformer is slow and directional, which impedes the diffusion of dissolved gases in the transformer oil, thereby hindering timely fault detection. The results of this study offer significant insights for the installation of dissolved gas monitoring devices in field converter transformers and the determination of the optimal monitoring cycle interval.","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"32 5","pages":"3019-3027"},"PeriodicalIF":3.1,"publicationDate":"2025-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145210052","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Partial discharge (PD) detection is an effective method to evaluate the insulation status of cables for high-speed trains. Various factors in the detection process due to external interference make it difficult to get the ideal PD signal. Periodic narrow-band interference and random white noise are the main interference factors in the PD signal. A PD denoising method based on singular spectrum analysis (SSA) and improved adaptive noise-complete ensemble empirical modal decomposition (ICEEMDAN) is proposed in this article. With the method, by selecting the maximum value of singularity slope as the dividing point between narrowband interference and valid signal after grouping, the SSA algorithm selects the valid signal part for signal reconstruction, the noisy PD signal with white noise interference is decomposed into multiple eigenmodes by ICEEMDAN decomposition, which effectively avoids the modal blending in the empirical modal decomposition, sorts the intrinsic mode function (IMF) components further by the kurtosis criterion, and reconstructs the filtered IMF components, which extracts the pure ideal PD signal. Through denoising analysis of simulated PD signals and measured signals, the noise rejection ratio (NRR) of this method is 19.1836 in the laboratory and 16.389 in the depot, both higher than other methods. Therefore, this method has better denoising effect on noisy PD signals and can retain the original PD information to a higher degree.
{"title":"Partial Discharge Denoising of High-Voltage Cables for High-Speed Trains Based on Singular Spectrum Analysis and ICEEMDAN Decomposition","authors":"Guoqiang Gao;Shiyu Zhan;Siwei Yang;Shuyuan Zhou;Kai Liu;Kui Chen;Dongli Xin;Yujing Tang;Guangning Wu","doi":"10.1109/TDEI.2025.3564933","DOIUrl":"https://doi.org/10.1109/TDEI.2025.3564933","url":null,"abstract":"Partial discharge (PD) detection is an effective method to evaluate the insulation status of cables for high-speed trains. Various factors in the detection process due to external interference make it difficult to get the ideal PD signal. Periodic narrow-band interference and random white noise are the main interference factors in the PD signal. A PD denoising method based on singular spectrum analysis (SSA) and improved adaptive noise-complete ensemble empirical modal decomposition (ICEEMDAN) is proposed in this article. With the method, by selecting the maximum value of singularity slope as the dividing point between narrowband interference and valid signal after grouping, the SSA algorithm selects the valid signal part for signal reconstruction, the noisy PD signal with white noise interference is decomposed into multiple eigenmodes by ICEEMDAN decomposition, which effectively avoids the modal blending in the empirical modal decomposition, sorts the intrinsic mode function (IMF) components further by the kurtosis criterion, and reconstructs the filtered IMF components, which extracts the pure ideal PD signal. Through denoising analysis of simulated PD signals and measured signals, the noise rejection ratio (NRR) of this method is 19.1836 in the laboratory and 16.389 in the depot, both higher than other methods. Therefore, this method has better denoising effect on noisy PD signals and can retain the original PD information to a higher degree.","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"32 4","pages":"2294-2303"},"PeriodicalIF":3.1,"publicationDate":"2025-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144739801","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-07DOI: 10.1109/TDEI.2025.3567949
Xiangdong Liu;Yunqi Xing;Jingyu Mu;Wen Su;Tengfei Li;Giovanni Mazzanti;Weiqi Qin;Chuanyang Li
Under the direct current (dc) electric field, the metal particles inside gas-insulated switchgear (GIS)/gas-insulated transmission line (GIL) exhibit reciprocating bouncing and firefly movements, which pose a relatively large hazard to the insulation system. This article explores the roles slope electrode and ground electrode coating play on restraining the of metal particle motion. The results show that in the case of the slope electrode, the movement of metal particles is affected by the reflection angle and the electric field gradient force. Among them, the electrode reflection angle drive is dominant when the spherical metal particles move through the insulating gas gap, while the electric field gradient force drive is dominant when the linear metal particles fly; the coating has a significant effect on increasing the take-off voltage of spherical metal particles, but the effect of increasing the take-off voltage of linear metal particles depends on the contact mode between the particles and the coated electrode when they are stationary. Approximately 30% of the linear metal particles can be suppressed. The research results can provide a reference for the comprehensive suppression of metal particles in dc GIS/GIL.
{"title":"Electrodes Coordination in Suppressing Metal Particle in DC Gas-Insulated Asset: Fundamental Research","authors":"Xiangdong Liu;Yunqi Xing;Jingyu Mu;Wen Su;Tengfei Li;Giovanni Mazzanti;Weiqi Qin;Chuanyang Li","doi":"10.1109/TDEI.2025.3567949","DOIUrl":"https://doi.org/10.1109/TDEI.2025.3567949","url":null,"abstract":"Under the direct current (dc) electric field, the metal particles inside gas-insulated switchgear (GIS)/gas-insulated transmission line (GIL) exhibit reciprocating bouncing and firefly movements, which pose a relatively large hazard to the insulation system. This article explores the roles slope electrode and ground electrode coating play on restraining the of metal particle motion. The results show that in the case of the slope electrode, the movement of metal particles is affected by the reflection angle and the electric field gradient force. Among them, the electrode reflection angle drive is dominant when the spherical metal particles move through the insulating gas gap, while the electric field gradient force drive is dominant when the linear metal particles fly; the coating has a significant effect on increasing the take-off voltage of spherical metal particles, but the effect of increasing the take-off voltage of linear metal particles depends on the contact mode between the particles and the coated electrode when they are stationary. Approximately 30% of the linear metal particles can be suppressed. The research results can provide a reference for the comprehensive suppression of metal particles in dc GIS/GIL.","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"33 1","pages":"698-706"},"PeriodicalIF":3.1,"publicationDate":"2025-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146102983","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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