Arnaud Nanfak, Abdelmoumene Hechifa, Samuel Eke, Abdelaziz Lakehal, Charles Hubert Kom, Sherif S. M. Ghoneim
This contribution presents a two-step hybrid diagnostic approach, combining k-means clustering for subset formation, followed by subset analysis conducted by human experts. As the feature input vector has a significant influence on the performance of unsupervised machine learning algorithms, seven feature input vectors derived from traditional methods, including Duval pentagon method, Rogers ratio method, three ratios technique, Denkyoken method, ensemble gas characteristics method, Duval triangle method, and Gouda triangle method were explored for the subset formation stage. The seven proposed individual methods, corresponding to the seven feature input vectors, were implemented using a dataset of 595 DGA samples and tested on an additional 254 DGA samples. Furthermore, a combined technique based on a support vector machine was introduced, utilising the diagnostic results of the individual methods as input features. From training and testing, with diagnostic outcomes of 91.09% and 90.94%, the combined technique demonstrated the highest overall diagnostic accuracies. Using the IEC TC10 database, the diagnosis accuracies of the proposed diagnostic methods were compared to existing methods of literature. From the results obtained, the combined technique outperformed the proposed individual methods and existing methods used for comparison.
{"title":"A combined technique for power transformer fault diagnosis based on k-means clustering and support vector machine","authors":"Arnaud Nanfak, Abdelmoumene Hechifa, Samuel Eke, Abdelaziz Lakehal, Charles Hubert Kom, Sherif S. M. Ghoneim","doi":"10.1049/nde2.12088","DOIUrl":"10.1049/nde2.12088","url":null,"abstract":"<p>This contribution presents a two-step hybrid diagnostic approach, combining <i>k</i>-means clustering for subset formation, followed by subset analysis conducted by human experts. As the feature input vector has a significant influence on the performance of unsupervised machine learning algorithms, seven feature input vectors derived from traditional methods, including Duval pentagon method, Rogers ratio method, three ratios technique, Denkyoken method, ensemble gas characteristics method, Duval triangle method, and Gouda triangle method were explored for the subset formation stage. The seven proposed individual methods, corresponding to the seven feature input vectors, were implemented using a dataset of 595 DGA samples and tested on an additional 254 DGA samples. Furthermore, a combined technique based on a support vector machine was introduced, utilising the diagnostic results of the individual methods as input features. From training and testing, with diagnostic outcomes of 91.09% and 90.94%, the combined technique demonstrated the highest overall diagnostic accuracies. Using the IEC TC10 database, the diagnosis accuracies of the proposed diagnostic methods were compared to existing methods of literature. From the results obtained, the combined technique outperformed the proposed individual methods and existing methods used for comparison.</p>","PeriodicalId":36855,"journal":{"name":"IET Nanodielectrics","volume":null,"pages":null},"PeriodicalIF":3.8,"publicationDate":"2024-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1049/nde2.12088","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141684788","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jurimart Wongsricha, Viyada Harnchana, P. Srepusharawoot, Nutthakritta Phromviyo, P. Moontragoon, P. Thongbai
This research investigated the influence of temperature and humidity on the giant dielectric (GD) properties of 1% indium tin oxide and 1% Ta2O5 co‐doped TiO2 ceramics sintered at different temperatures. A single phase of rutile TiO2 was obtained in all sintered samples. The mean grain size increased with higher sintering temperatures, resulting in ceramics with a relative density exceeding 98%. A uniform dispersion of dopants and major elements was achieved. Remarkably, the dielectric constant increased significantly from 2 × 103 to 3.7 × 104 with a rising sintering temperature, primarily due to the enlarged grain size. Concurrently, the authors observed low loss tangents, ranging from tanδ≈0.016 to 0.024 at 1 kHz. Slight variations in the dielectric constant were observed with temperature from room temperature up to 210°C, while maintaining remarkably low tanδ. The GD properties were attributed to space charge polarisation at internal interfaces and defect dipoles. Further research explored the impact of environmental conditions on dielectric properties. Remarkably, the ceramics exhibited minimal capacitance variations of less than 10% within the relative humidity range of 30%–95% and temperatures from 15 to 85°C, indicating excellent dielectric stability.
{"title":"Stability of giant dielectric properties in co‐doped rutile TiO2 ceramics under temperature and humidity","authors":"Jurimart Wongsricha, Viyada Harnchana, P. Srepusharawoot, Nutthakritta Phromviyo, P. Moontragoon, P. Thongbai","doi":"10.1049/nde2.12085","DOIUrl":"https://doi.org/10.1049/nde2.12085","url":null,"abstract":"This research investigated the influence of temperature and humidity on the giant dielectric (GD) properties of 1% indium tin oxide and 1% Ta2O5 co‐doped TiO2 ceramics sintered at different temperatures. A single phase of rutile TiO2 was obtained in all sintered samples. The mean grain size increased with higher sintering temperatures, resulting in ceramics with a relative density exceeding 98%. A uniform dispersion of dopants and major elements was achieved. Remarkably, the dielectric constant increased significantly from 2 × 103 to 3.7 × 104 with a rising sintering temperature, primarily due to the enlarged grain size. Concurrently, the authors observed low loss tangents, ranging from tanδ≈0.016 to 0.024 at 1 kHz. Slight variations in the dielectric constant were observed with temperature from room temperature up to 210°C, while maintaining remarkably low tanδ. The GD properties were attributed to space charge polarisation at internal interfaces and defect dipoles. Further research explored the impact of environmental conditions on dielectric properties. Remarkably, the ceramics exhibited minimal capacitance variations of less than 10% within the relative humidity range of 30%–95% and temperatures from 15 to 85°C, indicating excellent dielectric stability.","PeriodicalId":36855,"journal":{"name":"IET Nanodielectrics","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141341600","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. H. M. I. Ferdous, Md. Mynuddin, Khalid Sifulla Noor
The authors present an innovative photonic crystal fibre (PCF) detector that has the ability to detect sulphur dioxide (SO2) gas. This deadly gas having no tone at all with a strong aroma. Our suggested sensor is designed with heptagonal cladding along with octagonal core. It displays exclusive performance in detecting SO2 with an elevated relative sensitivity (RS). The max RS for this sensor is 87.39% with a tiny Confinement Loss of 6.8194 × 10−4 dB/m and having a total loss of 1.80609 × 10−2 dB/m at optimum frequency of 1.8 THz. Suggested PCF sensor also has effective material loss of 0.017379 cm−1 and effective area of 5.39710 × 10−8 m2. Among the principal air pollutants that can irritate and make respiration tough is SO2 and prolonged exposure could be a factor in permanent breathing problems. It also contributes to the development of acid rain, which damages aquatic environments. Therefore, it becomes necessary to detect this harmful gas and that can be effectively done with the proposed PCF sensor. The suggested PCF sensor can be crucial to minimise the air pollution rate. It will play a vital role for the improvement of human health safety from this deadly element.
{"title":"High‐performance sulphur dioxide sensor: Unveiling the potential of photonic crystal fibre technology","authors":"A. H. M. I. Ferdous, Md. Mynuddin, Khalid Sifulla Noor","doi":"10.1049/nde2.12084","DOIUrl":"https://doi.org/10.1049/nde2.12084","url":null,"abstract":"The authors present an innovative photonic crystal fibre (PCF) detector that has the ability to detect sulphur dioxide (SO2) gas. This deadly gas having no tone at all with a strong aroma. Our suggested sensor is designed with heptagonal cladding along with octagonal core. It displays exclusive performance in detecting SO2 with an elevated relative sensitivity (RS). The max RS for this sensor is 87.39% with a tiny Confinement Loss of 6.8194 × 10−4 dB/m and having a total loss of 1.80609 × 10−2 dB/m at optimum frequency of 1.8 THz. Suggested PCF sensor also has effective material loss of 0.017379 cm−1 and effective area of 5.39710 × 10−8 m2. Among the principal air pollutants that can irritate and make respiration tough is SO2 and prolonged exposure could be a factor in permanent breathing problems. It also contributes to the development of acid rain, which damages aquatic environments. Therefore, it becomes necessary to detect this harmful gas and that can be effectively done with the proposed PCF sensor. The suggested PCF sensor can be crucial to minimise the air pollution rate. It will play a vital role for the improvement of human health safety from this deadly element.","PeriodicalId":36855,"journal":{"name":"IET Nanodielectrics","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141368245","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Silicone rubber (SiR) is commonly used in reinforced insulation parts for high-voltage direct current (HVDC) cable accessories due to its excellent insulation, elasticity, and high-temperature resistance. HVDC cable accessories always suffer from the local electric field concentration due to the electrical conductivity mismatch between reinforced insulation and main insulation, which can ultimately lead to electric breakdown. The non-linear conductive composites based on SiR have the ability to adaptively adjust the distribution of the electric field in cable accessories. This is expected to solve the problem of localised electric field concentration. The zinc oxide (ZnO) and glycidyl methacrylate (GMA) are used as fillers and grafted modifier respectively to improve the non-linear electrical conductivity of ZnO/SiR-GMA composites. The results indicate that grafting GMA can increase electrical conductivity of SiR, while doping ZnO filler enables SiR to have non-linear conductivity characteristics. The combination of doping and grafting modification of the composites achieves excellent non-linear conductive properties at lower ZnO filler content. Additionally, the mechanical properties of the modified composites are enhanced. The simulation results indicate that ZnO/SiR-GMA is the most effective material for homogenising the electric field when used as reinforced insulation for cable intermediate joints.
硅橡胶(SiR)具有优异的绝缘性、弹性和耐高温性,因此常用于高压直流(HVDC)电缆附件的增强绝缘部件。由于增强绝缘和主绝缘之间的导电性能不匹配,高压直流电缆附件总是存在局部电场集中的问题,最终可能导致电气击穿。基于 SiR 的非线性导电复合材料能够自适应地调整电缆附件中的电场分布。这有望解决局部电场集中的问题。氧化锌(ZnO)和甲基丙烯酸缩水甘油酯(GMA)分别用作填料和接枝改性剂,以提高 ZnO/SiR-GMA 复合材料的非线性导电性。结果表明,接枝 GMA 可提高 SiR 的导电性,而掺杂 ZnO 填料可使 SiR 具有非线性导电特性。复合材料的掺杂和接枝改性相结合,可在较低的氧化锌填料含量下实现优异的非线性导电特性。此外,改性复合材料的机械性能也得到了提高。模拟结果表明,在用作电缆中间接头的增强绝缘材料时,ZnO/SiR-GMA 是均匀电场的最有效材料。
{"title":"Improvement in non-linear electrical conductivity of silicone rubber by incorporating zinc oxide fillers and grafting small polar molecules","authors":"Qingguo Chi, Huiyang Zhang, Zhaotong Meng, Changhai Zhang, Yongquan Zhang, Yue Zhang, Chao Yin, Tiandong Zhang","doi":"10.1049/nde2.12080","DOIUrl":"10.1049/nde2.12080","url":null,"abstract":"<p>Silicone rubber (SiR) is commonly used in reinforced insulation parts for high-voltage direct current (HVDC) cable accessories due to its excellent insulation, elasticity, and high-temperature resistance. HVDC cable accessories always suffer from the local electric field concentration due to the electrical conductivity mismatch between reinforced insulation and main insulation, which can ultimately lead to electric breakdown. The non-linear conductive composites based on SiR have the ability to adaptively adjust the distribution of the electric field in cable accessories. This is expected to solve the problem of localised electric field concentration. The zinc oxide (ZnO) and glycidyl methacrylate (GMA) are used as fillers and grafted modifier respectively to improve the non-linear electrical conductivity of ZnO/SiR-GMA composites. The results indicate that grafting GMA can increase electrical conductivity of SiR, while doping ZnO filler enables SiR to have non-linear conductivity characteristics. The combination of doping and grafting modification of the composites achieves excellent non-linear conductive properties at lower ZnO filler content. Additionally, the mechanical properties of the modified composites are enhanced. The simulation results indicate that ZnO/SiR-GMA is the most effective material for homogenising the electric field when used as reinforced insulation for cable intermediate joints.</p>","PeriodicalId":36855,"journal":{"name":"IET Nanodielectrics","volume":null,"pages":null},"PeriodicalIF":3.8,"publicationDate":"2024-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1049/nde2.12080","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141120301","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Arnaud Nanfak, Eke Samuel, Issouf Fofana, Fethi Meghnefi, Martial Gildas Ngaleu, Charles Hubert Kom
A key factor in ensuring the efficient and safe operation of power transformers is the early and accurate diagnosis of incipient faults. Among the tools available to achieve this goal, dissolved gas analysis (DGA) is widely used by power transformers' maintenance professionals. It is a preventive maintenance tool, used for condition monitoring, fault diagnosis and unplanned outage prevention. With the development of artificial intelligence (AI), many intelligent-based methods using AI tools have been proposed in the literature for DGA data interpretation. Although these methods achieve high diagnostic accuracies and improve DGA efficiency, they are generally complicated and the research documented in these publications is difficult to replicate. Traditional DGA-based methods are simple, easy to understand and implement, and widely used by power transformers' maintenance professionals. Many methods proposed in recent years overcome the limitations of the pioneer methods and are increasingly effective. The authors present a detailed and comprehensive literature review of the traditional DGA-based methods for mineral oil-immersed power transformer faults diagnosis. This review also addresses ways to improve the efficiency of the available traditional methods. Some pitfalls that need to be taken into account to improve the efficiency of the DGA-based diagnostic methods are also presented.
{"title":"Traditional fault diagnosis methods for mineral oil-immersed power transformer based on dissolved gas analysis: Past, present and future","authors":"Arnaud Nanfak, Eke Samuel, Issouf Fofana, Fethi Meghnefi, Martial Gildas Ngaleu, Charles Hubert Kom","doi":"10.1049/nde2.12082","DOIUrl":"10.1049/nde2.12082","url":null,"abstract":"<p>A key factor in ensuring the efficient and safe operation of power transformers is the early and accurate diagnosis of incipient faults. Among the tools available to achieve this goal, dissolved gas analysis (DGA) is widely used by power transformers' maintenance professionals. It is a preventive maintenance tool, used for condition monitoring, fault diagnosis and unplanned outage prevention. With the development of artificial intelligence (AI), many intelligent-based methods using AI tools have been proposed in the literature for DGA data interpretation. Although these methods achieve high diagnostic accuracies and improve DGA efficiency, they are generally complicated and the research documented in these publications is difficult to replicate. Traditional DGA-based methods are simple, easy to understand and implement, and widely used by power transformers' maintenance professionals. Many methods proposed in recent years overcome the limitations of the pioneer methods and are increasingly effective. The authors present a detailed and comprehensive literature review of the traditional DGA-based methods for mineral oil-immersed power transformer faults diagnosis. This review also addresses ways to improve the efficiency of the available traditional methods. Some pitfalls that need to be taken into account to improve the efficiency of the DGA-based diagnostic methods are also presented.</p>","PeriodicalId":36855,"journal":{"name":"IET Nanodielectrics","volume":null,"pages":null},"PeriodicalIF":3.8,"publicationDate":"2024-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1049/nde2.12082","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140675766","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Transmission lines and outdoor substations are replete with various forms of micro energy such as wind energy, solar energy, and electromagnetic energy. There exists micro energy in the forms of mechanical vibrations, temperature differences, and humidity in power distribution equipment. Innovative sensor or monitoring methods are needed to maintain the stability and digitisation of the grid. Unfortunately, there is limited study on the power supply of these sensor systems. Triboelectric nanogenerators, which are environmentally friendly and use simple materials, show excellent performance in environmental nano‐energy collection and self‐powered online monitoring. Therefore, environmental energy collection systems based on triboelectric nanogenerators are one of the selected methods to convert magnetic energy in the magnetic field into electrical energy. A model structure was designed using the contact separation mode, which is one of the four working modes of triboelectric nanogenerators, based on the strength of the magnetic field in the environment. This structure mainly consists of the friction layer, electrodes for current conduction, and connected loads. The research includes a comparison of four inherent electrical outputs of the triboelectric nanogenerator: open‐circuit voltage, short‐circuit current, capacitance, and power. COMSOL Multiphysics software was used for all modelling and simulation of the TENG. This software was used for the design, material selection, and static study of the TENG. When the relative dielectric constant was fixed, the output voltage reached and the energy reached . Overall, ideal reference can be provided for researchers studying power supply issues for sensors in complex magnetic field situations and help them design high‐performance TENGs.
输电线路和户外变电站充满了各种形式的微能量,如风能、太阳能和电磁能。配电设备中也存在机械振动、温差和湿度等形式的微能量。需要创新的传感器或监测方法来保持电网的稳定性和数字化。遗憾的是,有关这些传感器系统供电的研究十分有限。三电纳米发电机环保且材料简单,在环境纳米能量收集和自供电在线监测方面表现出色。因此,基于三电纳米发电机的环境能量收集系统是将磁场中的磁能转化为电能的首选方法之一。接触分离模式是三电纳米发电机的四种工作模式之一,根据环境中的磁场强度设计了一种模型结构。该结构主要由摩擦层、用于传导电流的电极和连接负载组成。研究包括比较三电纳米发电机的四种固有电气输出:开路电压、短路电流、电容和功率。TENG 的所有建模和仿真都使用了 COMSOL Multiphysics 软件。该软件用于 TENG 的设计、材料选择和静态研究。当相对介电常数固定时,输出电压达到.,能量达到.。总之,研究人员在研究复杂磁场情况下传感器的电源问题时,可以提供理想的参考,帮助他们设计高性能的 TENG。
{"title":"A simulation study on the contact‐separation triboelectric nano‐generator for magnetic energy harvester","authors":"Yibing Zhang, Fenghui Li, Yagang Wang, Shanlin Tong, Yuhao Li, Xuhui Li, Wu Lu, Yongsheng Liu","doi":"10.1049/nde2.12079","DOIUrl":"https://doi.org/10.1049/nde2.12079","url":null,"abstract":"Transmission lines and outdoor substations are replete with various forms of micro energy such as wind energy, solar energy, and electromagnetic energy. There exists micro energy in the forms of mechanical vibrations, temperature differences, and humidity in power distribution equipment. Innovative sensor or monitoring methods are needed to maintain the stability and digitisation of the grid. Unfortunately, there is limited study on the power supply of these sensor systems. Triboelectric nanogenerators, which are environmentally friendly and use simple materials, show excellent performance in environmental nano‐energy collection and self‐powered online monitoring. Therefore, environmental energy collection systems based on triboelectric nanogenerators are one of the selected methods to convert magnetic energy in the magnetic field into electrical energy. A model structure was designed using the contact separation mode, which is one of the four working modes of triboelectric nanogenerators, based on the strength of the magnetic field in the environment. This structure mainly consists of the friction layer, electrodes for current conduction, and connected loads. The research includes a comparison of four inherent electrical outputs of the triboelectric nanogenerator: open‐circuit voltage, short‐circuit current, capacitance, and power. COMSOL Multiphysics software was used for all modelling and simulation of the TENG. This software was used for the design, material selection, and static study of the TENG. When the relative dielectric constant was fixed, the output voltage reached and the energy reached . Overall, ideal reference can be provided for researchers studying power supply issues for sensors in complex magnetic field situations and help them design high‐performance TENGs.","PeriodicalId":36855,"journal":{"name":"IET Nanodielectrics","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140715642","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Meng Huang, Yuanxin Yao, Lu Wang, Sai Li, Yanxiao Su, Jie Ma
The fibrids in aramid insulation paper exhibit good adhesion ability. However, the effects of fibrids morphology on the mechanical and electrical properties of aramid insulation paper remains poorly understood. Aramid fibrids with different morphological structures were prepared by modifying the preparation process, and then they were used to fabricate aramid composite insulation paper under the same condition. The results showed that increasing the shear rate and aramid solution concentration affected the magnitude of the shear force and double diffusion process, thus affecting the average length, specific surface area, and crystallinity of the fibrids. When the rotor frequency is 25–30 Hz and the solution concentration is 15%, the fibrid has a large specific surface area while ensuring high crystallinity, which is beneficial to the improvement of breakdown strength. When the average length of fibrids is 0.8–1.4 mm, the fine content is 1.3%–2.3%, specific surface area is 57.5–62 m2 g−1, and crystallinity is 18.5%–27%, the aramid composite insulation paper has the optimal mechanical and electrical properties. Combined with the micromorphology test results, the influence mechanism of fibrids properties on the mechanical properties, dielectric properties, and AC and DC breakdown strength of aramid composite insulation paper was obtained. The result is of great theoretical significance and practical value for the preparation and application of high‐performance aramid composite insulation paper.
{"title":"Synergetic optimisation of mechanical and electrical properties of aramid composite insulation paper by modulation of fibrid morphology","authors":"Meng Huang, Yuanxin Yao, Lu Wang, Sai Li, Yanxiao Su, Jie Ma","doi":"10.1049/nde2.12081","DOIUrl":"https://doi.org/10.1049/nde2.12081","url":null,"abstract":"The fibrids in aramid insulation paper exhibit good adhesion ability. However, the effects of fibrids morphology on the mechanical and electrical properties of aramid insulation paper remains poorly understood. Aramid fibrids with different morphological structures were prepared by modifying the preparation process, and then they were used to fabricate aramid composite insulation paper under the same condition. The results showed that increasing the shear rate and aramid solution concentration affected the magnitude of the shear force and double diffusion process, thus affecting the average length, specific surface area, and crystallinity of the fibrids. When the rotor frequency is 25–30 Hz and the solution concentration is 15%, the fibrid has a large specific surface area while ensuring high crystallinity, which is beneficial to the improvement of breakdown strength. When the average length of fibrids is 0.8–1.4 mm, the fine content is 1.3%–2.3%, specific surface area is 57.5–62 m2 g−1, and crystallinity is 18.5%–27%, the aramid composite insulation paper has the optimal mechanical and electrical properties. Combined with the micromorphology test results, the influence mechanism of fibrids properties on the mechanical properties, dielectric properties, and AC and DC breakdown strength of aramid composite insulation paper was obtained. The result is of great theoretical significance and practical value for the preparation and application of high‐performance aramid composite insulation paper.","PeriodicalId":36855,"journal":{"name":"IET Nanodielectrics","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140792510","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Self-healing polyurethane diacrylate (PUDA) composites with outstanding thermal conductivity were prepared with variable boron nitride (BN) and a small number of graphene nanoplatelets (GNPs) (1 wt%). The thermal conductivity of PUDA composites containing 1 wt% GNPs and 29 wt% BN reached 1.73 W/(m·K), showing 27.2% increment compared to PUDA composites only with 30 wt% BN. BN and GNPs mutually promoted the dispersion in the PUDA matrix, and the small number of GNPs was enough to bridge the gaps between BN, so that GNPs and BN exerted a synergistic enhancement effect on the thermal conductivity of PUDA composites with a synergistic efficiency of 1.343. The PUDA composites maintained the tensile strength of 8.21 MPa with good electrical insulation (4.55 × 109 Ω cm). The high degrees of recovery of mechanical strength (>90%) and thermal conductivities (>84%) were also realised by the healing effect of the reversible DA reaction. The PUDA composites with excellent comprehensive properties show broad application potential in the thermal management of electronic devices.
{"title":"Enhanced thermal conductivity and self-healing property of PUDA/boron nitride micro-sheets composites with a small number of graphene nano-platelets","authors":"Shiyu Zhang, Zhihui Shang, Dongliang Ding, Xu Wang, Ya Wu, Shifeng Nian, Zhenguo Liu, Qiuyu Zhang, Yanhui Chen","doi":"10.1049/nde2.12073","DOIUrl":"10.1049/nde2.12073","url":null,"abstract":"<p>Self-healing polyurethane diacrylate (PUDA) composites with outstanding thermal conductivity were prepared with variable boron nitride (BN) and a small number of graphene nanoplatelets (GNPs) (1 wt%). The thermal conductivity of PUDA composites containing 1 wt% GNPs and 29 wt% BN reached 1.73 W/(m·K), showing 27.2% increment compared to PUDA composites only with 30 wt% BN. BN and GNPs mutually promoted the dispersion in the PUDA matrix, and the small number of GNPs was enough to bridge the gaps between BN, so that GNPs and BN exerted a synergistic enhancement effect on the thermal conductivity of PUDA composites with a synergistic efficiency of 1.343. The PUDA composites maintained the tensile strength of 8.21 MPa with good electrical insulation (4.55 × 10<sup>9</sup> Ω cm). The high degrees of recovery of mechanical strength (>90%) and thermal conductivities (>84%) were also realised by the healing effect of the reversible DA reaction. The PUDA composites with excellent comprehensive properties show broad application potential in the thermal management of electronic devices.</p>","PeriodicalId":36855,"journal":{"name":"IET Nanodielectrics","volume":null,"pages":null},"PeriodicalIF":3.8,"publicationDate":"2024-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1049/nde2.12073","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140221894","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
High conductivity loss and low breakdown strength of traditional polypropylene (PP) film in the high-temperature environment are the key factors limiting the application of metallised film capacitors (MFCs). The effect of cyclic olefin copolymers (COCs) with different glass transition temperatures (Tgs) on the dielectric performance of PP/COC composites at high temperature are studied. The results showed that the addition of COC enhanced the intermolecular interaction force, which led to the reduction of defects in the films. In addition, COC with high Tg inhibits the movement of molecular chains and enhances the thermal stability of the film, which limits the transport of carriers at high temperatures. The conductivity and breakdown strength of the modified films (with a Tg of 134°C for COC) at 125°C are 91.6% lower and 45.7% higher, respectively, than that of pure PP. This method shows great potential in improving the dielectric properties of PP at high temperatures.
{"title":"Improving the dielectric properties of polypropylene for metallised film capacitors based on cyclic olefin copolymer blending","authors":"Meng Xiao, Mengdie Zhang, Boxue Du, Kailun Fan","doi":"10.1049/nde2.12072","DOIUrl":"10.1049/nde2.12072","url":null,"abstract":"<p>High conductivity loss and low breakdown strength of traditional polypropylene (PP) film in the high-temperature environment are the key factors limiting the application of metallised film capacitors (MFCs). The effect of cyclic olefin copolymers (COCs) with different glass transition temperatures (Tgs) on the dielectric performance of PP/COC composites at high temperature are studied. The results showed that the addition of COC enhanced the intermolecular interaction force, which led to the reduction of defects in the films. In addition, COC with high Tg inhibits the movement of molecular chains and enhances the thermal stability of the film, which limits the transport of carriers at high temperatures. The conductivity and breakdown strength of the modified films (with a Tg of 134°C for COC) at 125°C are 91.6% lower and 45.7% higher, respectively, than that of pure PP. This method shows great potential in improving the dielectric properties of PP at high temperatures.</p>","PeriodicalId":36855,"journal":{"name":"IET Nanodielectrics","volume":null,"pages":null},"PeriodicalIF":3.8,"publicationDate":"2024-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1049/nde2.12072","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140252647","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Film capacitors are playing an increasingly important role in power-related fields, driven by the continuous development of dielectric materials and practical needs. Long-term accumulation has also led to an increasing wealth of data related to film capacitors. Sonification opens up a new way for people to make good use of data from film capacitors. A framework for sonifying film capacitors data based on TwoTone is presented. Based on the analysis and discussion, it is clear that the sonification results can easily represent the monotonic variation pattern of film capacitors data. What's more, the sonification results increase the possibility that people pay attention to the changing trend of film capacitors data when there is no significant difference in the visual perception of the data. In addition to providing a new way of music generation of electrical equipment, the method proposed is expected to contribute to theory reference in typical scenarios, such as factory calibration of film capacitors, monitoring of film capacitor operation status, and presentation of statistical data of film capacitors' dielectric materials, which will help us to better understand the distribution characteristics of polymer films.
{"title":"Data sonification of film capacitors","authors":"Yong-Xin Zhang, Di-Fan Liu, Xin-Yi Wei, Xin-Jie Wang, Fang-Yi Chen, Qi-Kun Feng, Wen-Yuan Cao, Wen-Zhuo Dong, Faisal Mehmood Shah, Yu-Xiao Liu, Zhi-Yuan Wu, Jian-Tao Wang, Shao-Long Zhong, Zhi-Min Dang","doi":"10.1049/nde2.12078","DOIUrl":"10.1049/nde2.12078","url":null,"abstract":"<p>Film capacitors are playing an increasingly important role in power-related fields, driven by the continuous development of dielectric materials and practical needs. Long-term accumulation has also led to an increasing wealth of data related to film capacitors. Sonification opens up a new way for people to make good use of data from film capacitors. A framework for sonifying film capacitors data based on TwoTone is presented. Based on the analysis and discussion, it is clear that the sonification results can easily represent the monotonic variation pattern of film capacitors data. What's more, the sonification results increase the possibility that people pay attention to the changing trend of film capacitors data when there is no significant difference in the visual perception of the data. In addition to providing a new way of music generation of electrical equipment, the method proposed is expected to contribute to theory reference in typical scenarios, such as factory calibration of film capacitors, monitoring of film capacitor operation status, and presentation of statistical data of film capacitors' dielectric materials, which will help us to better understand the distribution characteristics of polymer films.</p>","PeriodicalId":36855,"journal":{"name":"IET Nanodielectrics","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1049/nde2.12078","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140077412","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}