High VoltagePub Date : 2024-07-07DOI: 10.1049/hve2.12468
Wenjing Yin, Yunqing Wang, Hong Deng, Jiawei Wang, Xiaoke Gao, Ruoyu Huang, Kun He, Weijiang Chen, Tianyu Dong
{"title":"Mesh-free Monte Carlo method for electrostatic problems with floating potentials","authors":"Wenjing Yin, Yunqing Wang, Hong Deng, Jiawei Wang, Xiaoke Gao, Ruoyu Huang, Kun He, Weijiang Chen, Tianyu Dong","doi":"10.1049/hve2.12468","DOIUrl":"10.1049/hve2.12468","url":null,"abstract":"<p>Numerical simulation plays a crucial role in the analysis and design of power equipment, such as lightning protection devices, which may become inefficient using traditional grid-based methods when handling complex geometries of large problems. The authors propose a grid-free Monte Carlo method to handle electrostatic problems of complex geometry for both the interior and exterior domains, which is governed by the Poisson equation with a floating potential boundary condition that is neither a pure Dirichlet nor a Neumann condition. The potential and gradient at any given point can be expressed in terms of integral equations, which can be estimated recursively within the walk-on-sphere algorithm. Numerical examples have been demonstrated, including the evaluation of the mutual capacitance matrix of multi-conductor structures and lighting striking near real fractal trees. The proposed method shows advantages in terms of geometric flexibility and robustness, output sensitivity, and parallelism, which may become a candidate for game-changing numerical methods and exhibit great potential applications in high-voltage engineering.</p>","PeriodicalId":48649,"journal":{"name":"High Voltage","volume":"10 1","pages":"146-156"},"PeriodicalIF":4.4,"publicationDate":"2024-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1049/hve2.12468","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141671274","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}
High VoltagePub Date : 2024-07-04DOI: 10.1049/hve2.12467
Yongqi Wang, Kai Liu, Mu Lin, Hao Tang, Xining Li, Guangning Wu
{"title":"Analysis of electrical–thermal-stress characteristics for eccentric contact strip in the valve-side bushing of converter transformer","authors":"Yongqi Wang, Kai Liu, Mu Lin, Hao Tang, Xining Li, Guangning Wu","doi":"10.1049/hve2.12467","DOIUrl":"10.1049/hve2.12467","url":null,"abstract":"<p>Ultra-high voltage direct current (UHVDC) transmission project in China is expanding, and the technology is increasingly maturing. The converter transformer is a crucial component in the UHVDC transmission projects, and its valve-side bushing plays a key role in ensuring the stable operation of the power system. This paper investigates the electrical–thermal-stress distribution characteristics of the contact strip in an eccentric state. The research focuses on a section of the contact strip in the plug oil at the tail end of the bushing on the valve side of the converter. A three-dimensional finite element simulation model is established, and the contact strip contact resistance is used to define the contact strip eccentricity. The temperature rise platform of the contact strip was constructed to verify the precision of the simulation outcomes. The study investigated the variations in electric, thermal, and stress of contact strips in various eccentric states, as well as transient development, and the four stages of contact strip deformation were summarised using calculation results, providing quantitative analysis criteria for assessing the degree of deterioration of contact strips under eccentric conditions. Through the test and calculation, it can be seen that the contact resistance of the normal contact strip changes with the height in the form of a typical first-order exponential function. The contact resistance value is between 200 and 400 μΩ under the actual mounting height; for the brand-new contact strip, the maximum temperature difference is 2.984 K without other interference; and after 15 min, the maximum displacements of the upper and lower half-ring strips reached are 84.3 and 83.7 μm, respectively, due to the thermal expansion. The study results offer a theoretical foundation for understanding the failure of elastic electrical connection components in the bushing on the valve side of the converter.</p>","PeriodicalId":48649,"journal":{"name":"High Voltage","volume":"10 1","pages":"106-115"},"PeriodicalIF":4.4,"publicationDate":"2024-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1049/hve2.12467","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141679254","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}
High VoltagePub Date : 2024-07-04DOI: 10.1049/hve2.12471
Xu Dai, Yuan Yuan, Jie Xiao, Chenghao Jiang, Xujiang Hua, Huiying Xiang, Tao Zhu, Guoyong Liu, Jiang Zhou, Ruijin Liao
{"title":"Influence of different anodised nanoporous structures on the anti-icing and electrical properties of transmission Al lines","authors":"Xu Dai, Yuan Yuan, Jie Xiao, Chenghao Jiang, Xujiang Hua, Huiying Xiang, Tao Zhu, Guoyong Liu, Jiang Zhou, Ruijin Liao","doi":"10.1049/hve2.12471","DOIUrl":"10.1049/hve2.12471","url":null,"abstract":"<p>Ice accumulation of overhead transmission lines can lead to serious damage to power systems. Superhydrophobic nanostructured Al conductors are proposed to replace the de-icing or ice-melting equipment for economic advantages, good anti-icing properties and robust electrical performance. Anodisation under different direct current densities is adopted to fabricate two nanostructures on Al conductors, including the reticular and honeycomb-like nanoporous structures. Compared to pure Al conductors, the anodised surface of honeycomb-like nanoporous structures exhibits lower ice adhesion (3.82 kPa) and ice accumulation. Aluminium conductor steel reinforced treated in the proposed method has also been validated to exhibit a significant anti-glaze icing property. Additionally, corona performance and line loss are experimentally measured and calculated to prove good electrical performance. The 0.27 A Al strand shows the highest corona inception voltage (27.86 kV) and the lowest AC resistance (4.65 Ω/km), which is attributed to the good dielectric property and heat dissipation. Therefore, the proposed anti-icing transmission conductors show profound application potential for power systems.</p>","PeriodicalId":48649,"journal":{"name":"High Voltage","volume":"10 1","pages":"167-177"},"PeriodicalIF":4.4,"publicationDate":"2024-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1049/hve2.12471","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141678087","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}
High VoltagePub Date : 2024-07-03DOI: 10.1049/hve2.12462
Guangjin Zhang, Tianyu Han, Tao Wen, Yi Zhao, Weijiang Chen, Qiaogen Zhang, Jinzhong Li, Ke Wang
{"title":"The relationship between power of arc discharge in transformer oil and peak value of the shock wave","authors":"Guangjin Zhang, Tianyu Han, Tao Wen, Yi Zhao, Weijiang Chen, Qiaogen Zhang, Jinzhong Li, Ke Wang","doi":"10.1049/hve2.12462","DOIUrl":"10.1049/hve2.12462","url":null,"abstract":"<p>Since 2018, there have been seven incidents of explosions and fires in ultra-high voltage transformers in China, which are caused by internal arc discharge in transformer oil. Various pressure measurement experiments have been conducted to explore the laws of discharge pressure. However, differences in experimental conditions, discharge energy, and current peak values have led to discrepancies in the discharge power and pressure laws in these experiments. Thus, it is crucial to investigate the relationship between arc discharge power and pressure peak in transformer oil. An arc discharge test platform was established to measure pressure waveforms based on the <i>RLC</i> circuit. Additionally, a shadow optical path observation system was implemented to record the development process of discharge arc, bubble pulsation, and shock waves. The study reveals the positive relationship between the average power and the peak value of the shock wave; the former refers to the breakdown and expansion stage of the arc channel, and the latter is generated by the discharge, respectively. Overall, the pressure generation mechanism of arc discharge in transformer oil and the relationship between arc discharge power and peak value of discharge pressure are revealed.</p>","PeriodicalId":48649,"journal":{"name":"High Voltage","volume":"10 1","pages":"157-166"},"PeriodicalIF":4.4,"publicationDate":"2024-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1049/hve2.12462","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141680869","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}
{"title":"10 kV nanosecond pulse generator with high voltage gain and reduced switches","authors":"Jiuxin Ma, Liang Yu, Chenguo Yao, Shoulong Dong, Chengxiang Li, Lvheng Ren, Shixin Wang","doi":"10.1049/hve2.12470","DOIUrl":"10.1049/hve2.12470","url":null,"abstract":"<p>In the article, a new type boost high-voltage nanosecond pulse generator is proposed. The distributed inductance of the transmission line is utilised as the energy storage unit and cooperated with the variable impedance transmission line transformer to generate nanosecond pulses with extremely high-voltage gain. What’s more, the isolation effect caused by the transmission line time delay is applied to achieve modular stacking. The demand for charging power supply can be greatly reduced, and few switches are used. Finally, the topological principle is verified by experiments, and a prototype of the five-stage stacking prototype is built. With the charging voltage of 28 V, the generator can output pulse with a voltage amplitude of 10 kV and pulse width of 12 ns whose voltage gain is up to 357 times.</p>","PeriodicalId":48649,"journal":{"name":"High Voltage","volume":"9 5","pages":"1059-1067"},"PeriodicalIF":4.4,"publicationDate":"2024-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1049/hve2.12470","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141683435","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}
High VoltagePub Date : 2024-06-21DOI: 10.1049/hve2.12469
Dong Liang, Bingyin Xu, Pengwei Wang, Wei Wang
{"title":"Comprehensive study on tree-contact single-phase-to-ground faults: Modelling, risk analysis, and detection recommendations","authors":"Dong Liang, Bingyin Xu, Pengwei Wang, Wei Wang","doi":"10.1049/hve2.12469","DOIUrl":"https://doi.org/10.1049/hve2.12469","url":null,"abstract":"<p>Tree-contact single-phase-to-ground faults (TSFs) present a significant fire hazard in electrical distribution systems, and research on the development, modelling, and monitoring is insufficient. This article investigates the electro-thermal coupling mechanisms during the current rise of TSFs, constructing a simplified power–frequency model that leverages actual physical parameters like tree size for prolonged simulations of the first TSF stage zero-sequence current. Validated through full-scale testing, the model enables digital simulations across various tree sizes, concluding that the detection sensitivity for grounding faults should not exceed 0.5 A to mitigate fire risks effectively. This approach surpasses the limitations of traditional high-impedance fault models reliant on empirical parameters and the shortcomings of generalised conclusions from experimental inductions, offering a new paradigm for TSF research that enhances the predictive accuracy and applicability of fault analysis in electrical distribution networks.</p>","PeriodicalId":48649,"journal":{"name":"High Voltage","volume":"9 6","pages":"1280-1287"},"PeriodicalIF":4.4,"publicationDate":"2024-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1049/hve2.12469","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143253024","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}
High VoltagePub Date : 2024-06-21DOI: 10.1049/hve2.12451
Yin Zhang, Yan Li, Jin Yan, Chao Bian, Xuan Chen, Xiaoxing Zhang
{"title":"SO2 and SOF2 simultaneous detection by single mid-infrared laser based on tunable diode laser absorption spectroscopy","authors":"Yin Zhang, Yan Li, Jin Yan, Chao Bian, Xuan Chen, Xiaoxing Zhang","doi":"10.1049/hve2.12451","DOIUrl":"https://doi.org/10.1049/hve2.12451","url":null,"abstract":"<p>In the detection of multi-component gas based on tunable diode laser absorption spectroscopy (TDLAS), the problem of overlapping interference between the absorption lines of each gas is often encountered. For example, when detecting a gas mixture of sulphur dioxide (SO<sub>2</sub>) and thionyl fluoride (SOF<sub>2</sub>), the characteristic decomposition components of SF<sub>6</sub>, there is overlapping interference in the absorption lines of the two gases, which makes it difficult to detect the concentration of gases accurately. In view of this problem, a novel method based on support vector regression model used for TDLAS is proposed to detect two gases simultaneously. The detection results show that the correlation coefficients between the concentration of SO<sub>2</sub> and SOF<sub>2</sub> and the average value of the second harmonic peak reached 0.992 and 0.993. In addition, through model testing, different concentrations of SO<sub>2</sub> and SOF<sub>2</sub> gas mixture are simultaneously detected, and the resulting maximum errors for measuring SO<sub>2</sub> and SOF<sub>2</sub> concentrations are less than 7.13 × 10<sup>−5</sup> and 0.26 × 10<sup>−2</sup>. The maximum errors of the measurement results in the verification test are not more than 6.4 × 10<sup>−3</sup> and 4.6 × 10<sup>−2</sup>. Therefore, with assistance of the novel method, the detection of multiple gases by using a single laser is achieved.</p>","PeriodicalId":48649,"journal":{"name":"High Voltage","volume":"9 4","pages":"786-793"},"PeriodicalIF":4.4,"publicationDate":"2024-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1049/hve2.12451","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142007245","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}
High VoltagePub Date : 2024-06-19DOI: 10.1049/hve2.12461
Kai Yin, Qihong Fan, Jing Li, Taqi ur Rahman, Tianyin Zhang, Ashish Paramane, Xiangrong Chen
{"title":"Influence of imidazolium ionic liquids as organic filler dispersant on electrical properties of chitin/epoxy composites","authors":"Kai Yin, Qihong Fan, Jing Li, Taqi ur Rahman, Tianyin Zhang, Ashish Paramane, Xiangrong Chen","doi":"10.1049/hve2.12461","DOIUrl":"https://doi.org/10.1049/hve2.12461","url":null,"abstract":"<p>Ionic liquid (IL) as the dispersant can help disperse the organic nanofillers to improve the performance of epoxy resin remarkably. However, the effect of IL on the electrical properties of epoxy composites is not well documented. This comprehensive study consists of the preparation, material characterisation and systematical investigation of electrical properties of 1-Butyl-3-methylimidazole hexafluorophosphate-modified chitin fibre/epoxy composites. The findings show that introducing IL into a chitin/epoxy composite can minimise porosity defects and improve the compatibility between filler and matrix. However, a high concentration of IL induces severe charge injection into chitin/epoxy composites and internal electric field distortion. The addition of 0.75%–1.5% mass fraction IL results in maximum enhancement in the AC breakdown strength of the chitin/epoxy composite (by ∼71%) compared with the non-IL composites. The non-linear conductivity and non-uniform charge injection phenomena of IL-modified composites can be attributed to the movement of radicals and anions due to the decomposition of IL. Through this study, it is highly expected that the organic filler dispersion in the epoxy matrix can be optimised by tuning IL to improve the insulation properties.</p>","PeriodicalId":48649,"journal":{"name":"High Voltage","volume":"9 4","pages":"930-938"},"PeriodicalIF":4.4,"publicationDate":"2024-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1049/hve2.12461","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142007249","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}
High VoltagePub Date : 2024-06-19DOI: 10.1049/hve2.12457
Yanyang Yin, Wenqing Zhou, Zhiheng Wu, Jiasheng Huang, Xiaodong Liu, Jian Wang, Gang Liu
{"title":"Revitalising high voltage cable: Exploring effective repair methods and influential factors for buffer layer defects using conductive silicone rubber","authors":"Yanyang Yin, Wenqing Zhou, Zhiheng Wu, Jiasheng Huang, Xiaodong Liu, Jian Wang, Gang Liu","doi":"10.1049/hve2.12457","DOIUrl":"https://doi.org/10.1049/hve2.12457","url":null,"abstract":"<p>In recent years, the ablative discharge of the buffer layer in high-voltage (HV) cross-linked polyethylene (XLPE) cables has become a significant challenge for the operation and maintenance of power lines. However, there is a lack of effective methods to address buffer layer discharge defects. A practical approach is proposed to repair buffer layer defects and mitigate the associated discharge issues. To achieve this goal, the principles of repairing buffer layer defects are analysed by establishing an electrical network model that considers different contact states between the buffer layer and aluminium sheath. Based on this analysis, a method involving the injection of solidifiable rejuvenation fluid between the buffer layer and aluminium sheath is proposed to effectively suppress buffer layer discharge defects. Through simulation calculations, the minimum electrical conductivity and injection volume required to establish a reliable electrical connection between the buffer layer and aluminium sheath is determined. Additionally, a curable rejuvenation fluid containing conductive carbon black silicone rubber is prepared and analysed for its conductivity and flow properties at both the mesoscopic and macroscopic levels. Finally, a real cable office discharge test is conducted to compare the discharge behaviour of defective cables before and after repair. The results demonstrate that when the conductivity of the rejuvenation fluid exceeds 10<sup>−6</sup> S/m, it effectively establishes a conductive channel between the insulation shield and aluminium sheath, thereby reducing the risk of discharge ablation. Furthermore, after injecting the rejuvenation fluid and completely covering the white mark defect, the discharge phenomenon in the buffer layer is significantly suppressed, leading to the restoration of its electrical performance.</p>","PeriodicalId":48649,"journal":{"name":"High Voltage","volume":"9 6","pages":"1357-1369"},"PeriodicalIF":4.4,"publicationDate":"2024-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1049/hve2.12457","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143252922","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}
High VoltagePub Date : 2024-06-19DOI: 10.1049/hve2.12460
Gijs Lagerweij, Mohamad Ghaffarian Niasar
{"title":"Design of a high-frequency transformer based on amorphous cut cores for insulation breakdown testing","authors":"Gijs Lagerweij, Mohamad Ghaffarian Niasar","doi":"10.1049/hve2.12460","DOIUrl":"https://doi.org/10.1049/hve2.12460","url":null,"abstract":"<p>Innovative test methods are required to keep up with the increased demand for insulation materials which can withstand the high-frequency square-wave voltages generated by power-electronic equipment. Test systems using high-voltage, high-frequency transformers have proven versatile and easy to realise. The authors investigate the application of amorphous cut cores in such transformers. Analytical and numerical models for the transformer and its frequency response are developed, aiding the design process. An amorphous core-based transformer is designed for 8 kV<sub>pk</sub> output at 100 kHz and compared to two previous designs based on ferrite cores. The frequency and pulse response, as well as the high-voltage and thermal performance, are evaluated. The comparison shows that while the low parasitics of the amorphous-based transformer allow for superior frequency response, they are unsuitable for long-duration tests with high pulse repetition frequencies (25–100 kHz) due to increased core losses. The partial discharge inception and flashover voltage are comparable to the ferrite-based transformers.</p>","PeriodicalId":48649,"journal":{"name":"High Voltage","volume":"9 5","pages":"1183-1194"},"PeriodicalIF":4.4,"publicationDate":"2024-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1049/hve2.12460","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142540842","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}