High Voltage最新文献_第10页

Quantitative grading of insulation damage to distribution transformers caused by high-altitude electromagnetic pulse based on partial discharge detection 基于局部放电检测的高空电磁脉冲对配电变压器绝缘损伤定量分级

IF 4.9 2区工程技术

High Voltage Pub Date : 2024-12-30 DOI: 10.1049/hve2.12511

Feng Qin, Simeng Li, Wei Chen, Yuxiang Yang, Xin Nie, Wei Wu

{"title":"Quantitative grading of insulation damage to distribution transformers caused by high-altitude electromagnetic pulse based on partial discharge detection","authors":"Feng Qin, Simeng Li, Wei Chen, Yuxiang Yang, Xin Nie, Wei Wu","doi":"10.1049/hve2.12511","DOIUrl":"10.1049/hve2.12511","url":null,"abstract":"Distribution transformers may experience insulation breakdown or degradation when exposed to the influences of high-altitude electromagnetic pulse (HEMP), thus posing significant threats and uncertainties to the safety and stable operations of power systems. Therefore, this study constructs a HEMP impact-test platform for distribution transformers, evaluates and analyses the development patterns of partial discharge (PD) under the action of different amplitude conduction environments, decomposes and identifies the types of damage defects, proposes a quantitative classification method for the degree of HEMP damage to distribution transformers based on PD detection. And reveals the damage mechanism of distribution transformers exposed to HEMP at different damage levels. The results show that distribution transformers undergo insulation breakdown when subjected to the influences of HEMP and that performance degradation often occurs before breakdown. As the amplitude of the HEMP environment increases, the degree of transformer damage continues to deteriorate, and both the amount of PD and the repetition rate of discharges exhibit a step-wise increase, with the increase in the repetition rate lagging behind that of the discharge amount. Based on the patterns of discharge quantity and repetition rate, transformer damage is categorised into three stages: undamaged, latent defect discharge, and severe defect discharge.","PeriodicalId":48649,"journal":{"name":"High Voltage","volume":"10 4","pages":"1032-1042"},"PeriodicalIF":4.9,"publicationDate":"2024-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ietresearch.onlinelibrary.wiley.com/doi/epdf/10.1049/hve2.12511","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144915282","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Stress analysis and structural optimisation of insulating rods under dynamic and static loads 动态和静态载荷下绝缘棒的应力分析和结构优化

IF 4.9 2区工程技术

High Voltage Pub Date : 2024-12-30 DOI: 10.1049/hve2.12512

Haifeng Jin, Lijun Jin

{"title":"Stress analysis and structural optimisation of insulating rods under dynamic and static loads","authors":"Haifeng Jin, Lijun Jin","doi":"10.1049/hve2.12512","DOIUrl":"10.1049/hve2.12512","url":null,"abstract":"This study aims to provide a theoretical basis for the fatigue characteristics and structural optimisation of insulating rods to enhance their reliability and lifespan in practical applications. This paper uses COMSOL to complete the stress analysis of insulating rods under dynamic and static loads based on the finite element method. The correctness of the model is verified based on the elastic-plastic theory. The simulation results show that under the same load, the stress concentration area is more affected by the dynamic load, and the stress concentration position is highly consistent with the fracture position of the rod in the experiment. It verifies the impact on the insulating rods at different speeds and static load stress. Simulation shows that, in cases where the allowable stress is exceeded, as the number of operations increases, the fatigue characteristics will greatly affect the service life of the insulation rod. Finally, the fatigue analysis and structural optimisation of the insulating rod were completed, providing important reference values for the long-term stable operation of ultra-high voltage circuit breakers.","PeriodicalId":48649,"journal":{"name":"High Voltage","volume":"10 1","pages":"116-125"},"PeriodicalIF":4.9,"publicationDate":"2024-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1049/hve2.12512","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143536085","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Calculation and experimental verification of equivalent distributed circuit model based on refined iron core modelling 基于精铁芯建模的等效分布式电路模型计算与实验验证

IF 4.9 2区工程技术

High Voltage Pub Date : 2024-12-30 DOI: 10.1049/hve2.12501

Yunpeng Liu, Guanyu Chen, Fuseng Xu, Tao Zhao, Hongliang Liu, Lu Sun, Jiayi Guo

{"title":"Calculation and experimental verification of equivalent distributed circuit model based on refined iron core modelling","authors":"Yunpeng Liu, Guanyu Chen, Fuseng Xu, Tao Zhao, Hongliang Liu, Lu Sun, Jiayi Guo","doi":"10.1049/hve2.12501","DOIUrl":"10.1049/hve2.12501","url":null,"abstract":"This research introduces an equivalent circuit model and a computational method to address complex mechanical motion issues through electromechanical analogies. The study initially refines core vibration characteristics using single- and multi-degree-of-freedom models, subsequently establishing equivalent circuit models for these various degrees of freedom. However, employing high degree-of-freedom models for detailed modelling of the core proves overly cumbersome. The research advocates for a distributed equivalent circuit model to more accurately represent the core's layered structure, thus facilitating enhanced core modelling. Moreover, the study formulates a mechanical wave transmission equation pertinent to the vibration of the iron core, which constitutes the foundation of the distributed mechanical vibration model. This model comprehensively assesses the impact of three critical factors on core vibration: the non-linearity of winding resistance, the electromechanical coupling coefficient, and the dynamic stiffness of the core. A case study elucidates the distinct influences of each factor on vibration characteristics. Furthermore, this study derives vibration calculations from a 60-day overload ageing test conducted on a 10 kV transformer under 135°C overload conditions. The methodology involves integrating measured compression force values and the calculated dynamic stiffness of the core into an equivalent circuit model. Subsequent analysis compares the results from the equivalent circuit model with experimental measurements. These comparisons indicate an agreement between the calculated and measured values in the time–frequency domain, thereby confirming the accuracy of the equivalent circuit model calculations.","PeriodicalId":48649,"journal":{"name":"High Voltage","volume":"10 4","pages":"1020-1031"},"PeriodicalIF":4.9,"publicationDate":"2024-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ietresearch.onlinelibrary.wiley.com/doi/epdf/10.1049/hve2.12501","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144915281","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Significantly enhanced DC breakdown strength and high-temperature resistivity of cross-linked polyethylene through alloying polystyrene strategy 通过合金化聚苯乙烯策略，显著提高交联聚乙烯的直流击穿强度和高温电阻率

IF 4.9 2区工程技术

High Voltage Pub Date : 2024-12-30 DOI: 10.1049/hve2.12494

Muneeb Ahmed, Lisheng Zhong, Jinghui Gao, Fei Li, Nuo Xu, Wenpeng Li, Liang Cao

{"title":"Significantly enhanced DC breakdown strength and high-temperature resistivity of cross-linked polyethylene through alloying polystyrene strategy","authors":"Muneeb Ahmed, Lisheng Zhong, Jinghui Gao, Fei Li, Nuo Xu, Wenpeng Li, Liang Cao","doi":"10.1049/hve2.12494","DOIUrl":"10.1049/hve2.12494","url":null,"abstract":"Developing a stable insulation material stands as a crucial challenge for high-voltage direct current (HVDC) cable insulation. This work proposes an alloying strategy to significantly enhance the breakdown strength and high-temperature resistivity of cross-linked polyethylene (XLPE). The strategy involves blending low-density polyethylene (LDPE) with polystyrene (PS), resulting in a polymeric alloy. Confirmation of PS alloying within XLPE is supported by observed shifts in polyethylene miller indices (110) and (200) planes. The dicumyl peroxide used as a crosslinking agent demonstrates an ideal 1.41% enhancement in LDPE-PS crosslinking. The integration of aromatic ethers in the cross-linked network enhances temperature stability. Alloying PS at 220°C in XLPE leads to improved inter-molecular interactions and increased interfacial area, creating a sea–island morphology that resolves voids and limits defect or crack propagation by forming additional trapping sites. The enhanced breakdown strength and reduced conductivity of XLPE-PS are attributed to increased deep trapping sites and reduced carrier mobility resulting from alloying. The reduced conductivity at 70°C and 90°C demonstrates stability under electric fields. Remarkable breakdown strength improvements of 27.5% and 23.6% are observed at 30°C and 50°C. The proposed alloying strategy suggests replacing XLPE with advanced XLPE-PS, offering promising prospects for HVDC insulation.","PeriodicalId":48649,"journal":{"name":"High Voltage","volume":"10 4","pages":"953-963"},"PeriodicalIF":4.9,"publicationDate":"2024-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ietresearch.onlinelibrary.wiley.com/doi/epdf/10.1049/hve2.12494","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144915280","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Positive corona discharge of rod-plate electrodes in high-speed airflow 高速气流中棒板电极的正电晕放电

IF 4.9 2区工程技术

High Voltage Pub Date : 2024-12-28 DOI: 10.1049/hve2.12514

Qiang Wu, Yu Wang, Zhengxian Du, Zeliang Wu, Yeqiang Deng, Xishan Wen

{"title":"Positive corona discharge of rod-plate electrodes in high-speed airflow","authors":"Qiang Wu, Yu Wang, Zhengxian Du, Zeliang Wu, Yeqiang Deng, Xishan Wen","doi":"10.1049/hve2.12514","DOIUrl":"10.1049/hve2.12514","url":null,"abstract":"The characteristics of positive corona discharge of rod electrode in high-speed airflow are studied in this paper. The experiments were carried out in a wind tunnel with a maximum flow speed of 100 m/s in a dark room. The discharge voltage and current were recorded and the corona patterns were captured by a digital single lens reflex (DSLR) camera during the experiment. A discharge transition in rod electrode from streamer corona to mixed streamer-glow corona, and finally to stable glow discharge was observed with the voltage increased. The increase of airflow speed resulted in a decrease of each corona inception voltages. The streamers will be suppressed and shifted towards the upwind side, while the glow layer will be promoted and shifted towards the downwind side in low and upwind side in high voltages. The glow corona current and the voltage show a quadratic function and the higher the airflow speeds, the bigger the coefficient of square of voltage. The distributions of peaks, pulse widths and interval times of streamer pulses were analysed, showing good correspondence with the streamer images. The measurements were explained by combining particle transport and local air pressure distribution.","PeriodicalId":48649,"journal":{"name":"High Voltage","volume":"10 2","pages":"337-350"},"PeriodicalIF":4.9,"publicationDate":"2024-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1049/hve2.12514","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143893002","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Time–frequency characteristics and influencing factors of the pressure wave caused by power–frequency arc inside a closed oil tank 闭式油罐工频电弧压力波时频特性及影响因素

IF 4.9 2区工程技术

High Voltage Pub Date : 2024-12-28 DOI: 10.1049/hve2.12500

Yunfei Jia, Shengchang Ji, Xun Luo, Shuangrui Jia, Simeng Li

{"title":"Time–frequency characteristics and influencing factors of the pressure wave caused by power–frequency arc inside a closed oil tank","authors":"Yunfei Jia, Shengchang Ji, Xun Luo, Shuangrui Jia, Simeng Li","doi":"10.1049/hve2.12500","DOIUrl":"10.1049/hve2.12500","url":null,"abstract":"The arc faults inside oil-immersed power equipment can produce high-amplitude pressure waves inside tanks, which might cause ignition and explosion accidents. This kind of failure is one of the most severe faults for power equipment and has attracted considerable attention in recent years. However, due to the high risk of the experiments and the complex development of arc in oil, the characteristics of the pressure wave formed by the arc are still confusing. In this paper, the time–frequency characteristics of pressure waves are analysed using several experiments of 1–8 kA power–frequency arc inside a closed oil tank. The experimental results show that the pressure wave produced by the arc in oil contains three frequency bands, 0–500 Hz, 500 Hz–40 kHz, and above 40 kHz, which are related to the arc energy, the average current around arc ignition and the metal wire explosion respectively. This helps further understand the formation mechanism of the pressure wave caused by the arc in oil. This paper discusses the influences of ignition wire on arc-formed pressure waves. A wire diameter selection method for arc experiments is established to reduce the pressure differences between wire-ignited arcs and actual arc faults.","PeriodicalId":48649,"journal":{"name":"High Voltage","volume":"10 3","pages":"699-709"},"PeriodicalIF":4.9,"publicationDate":"2024-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1049/hve2.12500","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144519653","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Mechanism and suppression of breaking overvoltage of DC circuit breakers 直流断路器分断过电压的机理及抑制

IF 4.9 2区工程技术

High Voltage Pub Date : 2024-12-28 DOI: 10.1049/hve2.12491

Lu Qu, Zhangqing Yu, Zhizheng Gan, Xin Yan, Cheng Jiang, Yulong Huang, Mingshen Li, Jian Feng

引用次数: 0

Insulator defect detection under extreme weather based on synthetic weather algorithm and improved YOLOv7 基于合成天气算法和改进YOLOv7的极端天气下绝缘子缺陷检测

IF 4.9 2区工程技术

High Voltage Pub Date : 2024-12-25 DOI: 10.1049/hve2.12513

Yong Yang, Shuai Yang, Chuan Li, Yunxuan Wang, Xiaoqian Pi, Yuxin Lu, Ruohan Wu

{"title":"Insulator defect detection under extreme weather based on synthetic weather algorithm and improved YOLOv7","authors":"Yong Yang, Shuai Yang, Chuan Li, Yunxuan Wang, Xiaoqian Pi, Yuxin Lu, Ruohan Wu","doi":"10.1049/hve2.12513","DOIUrl":"10.1049/hve2.12513","url":null,"abstract":"Efficient and accurate insulator defect detection is essential for maintaining the safe and stable operation of transmission lines. However, the detection effectiveness is adversely impacted by complex and changeable environmental backgrounds, particularly under extreme weather that elevates accident risks. Therefore, this research proposes a high-precision intelligent strategy based on the synthetic weather algorithm and improved YOLOv7 for detecting insulator defects under extreme weather. The proposed methodology involves augmenting the dataset with synthetic rain, snow, and fog algorithm processing. Additionally, the original dataset undergoes augmentation through affine and colour transformations to improve model's generalisation performance under complex power inspection backgrounds. To achieve higher recognition accuracy in severe weather, an improved YOLOv7 algorithm for insulator defect detection is proposed, integrating focal loss with SIoU loss function and incorporating an optimised decoupled head structure. Experimental results indicate that the synthetic weather algorithm processing significantly improves the insulator defect detection accuracy under extreme weather, increasing the mean average precision by 2.4%. Furthermore, the authors’ improved YOLOv7 model achieves 91.8% for the mean average precision, outperforming the benchmark model by 2.3%. With a detection speed of 46.5 frames per second, the model meets the requirement of real-time detection of insulators and their defects during power inspection.","PeriodicalId":48649,"journal":{"name":"High Voltage","volume":"10 1","pages":"69-77"},"PeriodicalIF":4.9,"publicationDate":"2024-12-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1049/hve2.12513","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143536095","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

DC allowable electric field strength for naphthenic-based and paraffin-based transformer oils 环烷基和石蜡基变压器油的直流允许电场强度

IF 4.9 2区工程技术

High Voltage Pub Date : 2024-12-24 DOI: 10.1049/hve2.12506

Chunjia Gao, Bo Qi, Binhao Chen, Juzhen Wu, Chengrong Li

{"title":"DC allowable electric field strength for naphthenic-based and paraffin-based transformer oils","authors":"Chunjia Gao, Bo Qi, Binhao Chen, Juzhen Wu, Chengrong Li","doi":"10.1049/hve2.12506","DOIUrl":"10.1049/hve2.12506","url":null,"abstract":"Currently, the design of transformers insulation predominantly depends on the allowable alternating current (AC) field values for insulating oil established by Weidmann in the 1980s, lacking the research under direct current (DC) voltage for converter transformers. This study selects naphthenic oils and paraffin-based oil transformer oil as research subjects, establishing a practical measurement platform to ascertain the oil breakdown characteristics under DC voltage. Furthermore, it statistically analyses the allowable DC field values of the oil. The findings elucidate that (1) the three-parameter Weibull distribution is more suitable to conduct a statistical analysis for oil breakdown probability, yielding a fitting degree up to 99.95%. (2) For a constant electrode spacing, a 14.81% voltage increment escalates the breakdown probability of the oil gap from 3.33% to 73.33%. Concurrently, an increase in electrode spacing leads to a substantial decrement in the breakdown field strength of transformer oil, with KI25X experiencing a 54.51% reduction as electrode spacing extends from 5 to 25 mm. (3) The constant terms of the allowable DC field strength for S4, KI50X, and KI25X are found to be 19.728, 17.221, and 19.281, respectively. (4) A thorough analysis for differences in physicochemical properties and electrical parameters elucidates the variations in insulation properties across different transformer oils. The findings presented in this study offer essential theoretical and technical foundations for the design, evaluation, and enhancement of insulation structures in converter transformers.","PeriodicalId":48649,"journal":{"name":"High Voltage","volume":"10 3","pages":"760-772"},"PeriodicalIF":4.9,"publicationDate":"2024-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1049/hve2.12506","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144520288","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Adhesion characteristics of carbon particles on the surface of epoxy resin in insulating oil under DC electric field and influencing factors 直流电场作用下绝缘油中环氧树脂表面碳颗粒的附着特性及影响因素

IF 4.9 2区工程技术

High Voltage Pub Date : 2024-12-23 DOI: 10.1049/hve2.12499

Zijian Dong, Zhanlong Zhang, Jiarong Zhong, Zhixuan Xue, Yu Yang, Zhicheng Pan, Jin Fang

{"title":"Adhesion characteristics of carbon particles on the surface of epoxy resin in insulating oil under DC electric field and influencing factors","authors":"Zijian Dong, Zhanlong Zhang, Jiarong Zhong, Zhixuan Xue, Yu Yang, Zhicheng Pan, Jin Fang","doi":"10.1049/hve2.12499","DOIUrl":"10.1049/hve2.12499","url":null,"abstract":"The adhesion of carbon particles on the surface of epoxy resin in insulating oil is a significant factor contributing to surface flashover. However, there is currently a lack of a dynamic model that can reasonably explain the adhesion process of impurity particles, and the characteristics of particle adhesion are not yet clear, making it difficult to assess the risks of insulation contamination and surface flashover of valve-side bushing capacitance core. In this study, based on the Johnson–Kendall–Roberts (JKR) theory and the normal distribution characteristics of particle charges, the adhesion probability model of conductive particles in insulating oil on the surface of epoxy resin under DC electric fields was established, and carbon particle adhesion experiments were conducted to verify the accuracy of the model. The impact of electric field intensity, particle size, particle charge, and surface energy of the insulation material on the adhesion characteristics of carbon particles was investigated using the proposed model. The results can be utilised for the assessment of insulation contamination risks of valve-side bushing capacitance core and serves as a vital theoretical foundation for guiding the optimisation of anti-contamination structures in internal insulation and the development of advanced pollution-resistant and flashover-resistant insulation materials.","PeriodicalId":48649,"journal":{"name":"High Voltage","volume":"10 2","pages":"505-516"},"PeriodicalIF":4.9,"publicationDate":"2024-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1049/hve2.12499","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143892846","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0