{"title":"Experimental Study on Creeping Flashover Characteristics Along Dielectric Surfaces in Oil-Filled Transformer Using Electro-Optic Coupling Method","authors":"Lei Yao, Jianan Weng, Muzi Li, Maomao Zhang","doi":"10.1049/nde2.70004","DOIUrl":"https://doi.org/10.1049/nde2.70004","url":null,"abstract":"<p>Winding deformations and insulation dampness are the two main causes for the creeping flashover along the dielectric surfaces of oil-immersed power transformers, which could lead to main insulation failures and explosions. In this paper, these two types of insulation defects are modelled by evaluating creeping discharge tests due to moisture dripping and local electric field enhancement in a transformer protype. The completed creeping process along the dielectric interface, from partial discharge initiation to eventual flashover, was observed using an SLR camera and electro-optical coupled sensors. The results indicate that the evolution of the two types of discharges can be divided into four stages, that is, initial weak discharge at the tip of the high voltage side, appearance of carbonised traces at the tip, strong arc discharge in the gap between the high and low voltage sides and eventual flashover. Creeping discharges caused by insulation dampness grow faster than that caused by winding deformations, in terms of discharge intensity and carbonised pressboard areas. Therefore, the more serious surface discharge phenomenon under the condition of insulation and humidity in this paper is mainly caused by the more obvious space charge accumulation brought by low-density areas such as bubbles.</p>","PeriodicalId":36855,"journal":{"name":"IET Nanodielectrics","volume":"8 1","pages":""},"PeriodicalIF":3.8,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1049/nde2.70004","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143835774","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}
Rahmat Ullah, Israr Ullah, Rizwan Ahmed, Alistair Reid, Manu Haddad
{"title":"Revitalising DC-Aged Silicone Rubber Composites: Hybrid-Silica/Alumina Triumph Over Multi-Stress Ageing","authors":"Rahmat Ullah, Israr Ullah, Rizwan Ahmed, Alistair Reid, Manu Haddad","doi":"10.1049/nde2.70003","DOIUrl":"https://doi.org/10.1049/nde2.70003","url":null,"abstract":"<p>In this study, various concentrations of high-temperature vulcanised silicone rubber composites filled with nano/micro silica and alumina were manufactured. In this work, all test specimens were subjected to a variety of environmental stresses as well as DC voltage for 5000 h. Then, different diagnostic methods were used to look at the changes that happened on their surfaces and in their bulk properties. These included hydrophobicity classification, X-ray photoelectron spectroscopy (XPS) analysis, Fourier transform infrared spectroscopy (FTIR) analysis, thermogravimetric analysis (TGA) analysis, leakage current analysis and mechanical strength analysis. The composite with 2% nano silica and 10% micro alumina had the smoothest surface and the best hydrophobicity (HC-3). It also had the lowest leakage current (3.1 μA), the least amount of strength loss (31.3%), and good thermal stability compared to the other samples that were studied. Aged samples show a considerable increase in the concentration of the O element and a significant drop in the proportion of the Si component relative to the virgin specimen, which points to the oxidation of chemical bonds during HTV SR and their composites during ageing but with different concentrations. However, two samples (SP2 and SP3) showed comparatively lower concentrations of oxygen degradation in Si contents. This can be attributed to the strong molecular interaction between the fillers and the base matrix.</p>","PeriodicalId":36855,"journal":{"name":"IET Nanodielectrics","volume":"8 1","pages":""},"PeriodicalIF":3.8,"publicationDate":"2025-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1049/nde2.70003","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143475413","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}
Alireza Ghasemi, Mohsen Ashourian, Gholam Reza Amiri
{"title":"Synthesis and characterisation of \u0000 \u0000 \u0000 \u0000 Cu\u0000 0.5\u0000 \u0000 \u0000 Mg\u0000 0.5\u0000 \u0000 \u0000 Fe\u0000 2\u0000 \u0000 \u0000 O\u0000 4\u0000 \u0000 \u0000 ${text{Cu}}_{mathbf{0.5}}{text{Mg}}_{mathbf{0.5}}{text{Fe}}_{mathbf{2}}{mathbf{O}}_{mathbf{4}}$\u0000 nanoparticles doped with cadmium by co-precipitation method for acetonitrile, acetone, and ethanol gas detection with deep learning-based methods","authors":"Alireza Ghasemi, Mohsen Ashourian, Gholam Reza Amiri","doi":"10.1049/nde2.70001","DOIUrl":"https://doi.org/10.1049/nde2.70001","url":null,"abstract":"<p>In this study, a magnetic disk was prepared using nanoparticles with a diameter of less than 15 nm. The morphological and structural characteristics of these nanoparticles were systematically examined using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and alternating force gradient magnetometry (AGFM). XRD analysis confirmed that the average diameter of the copper–magnesium ferrite nanoparticles doped with cadmium was approximately 12 nm, consistent with TEM results, which also showed uniform particle distribution and a tendency to form clusters in powdered form. AGFM measurements revealed that the magnetic property of the powder sample was 15.83 emu/g, which increased to 22.70 emu/g after compression, highlighting the influence of particle density and morphology on magnetic behaviour. Gas sensing tests demonstrated that the fabricated sensors achieved exceptional sensitivity, particularly to acetonitrile, with a maximum sensitivity of 92.3%. A hybrid deep learning model, Bi-LSTM, was utilised to enhance the precision of gas classification. The proposed methodology was benchmarked against traditional machine learning models, including LSTM and RNN, and demonstrated superior performance. The accuracy of gas detection reached an impressive 99.89%, as validated by ROC analysis, underscoring the efficacy of the deep learning-based approach. These findings highlight the potential of cadmium-doped ferrite nanoparticles for high-performance gas sensing applications, suitable for both industrial and medical uses.</p>","PeriodicalId":36855,"journal":{"name":"IET Nanodielectrics","volume":"8 1","pages":""},"PeriodicalIF":3.8,"publicationDate":"2025-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1049/nde2.70001","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143404618","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}