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Digital Transformation Trend of the Pharmaceutical Distribution Industry in the Context of New Infrastructure in China
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作者 Gan Xingzhi 《Asian Journal of Social Pharmacy》 2024年第2期159-167,共9页
Objective To study the pharmaceutical distribution industry against the background of new infrastructure construction since it is vital to the health and life of the public,and to offer some suggestions to further imp... Objective To study the pharmaceutical distribution industry against the background of new infrastructure construction since it is vital to the health and life of the public,and to offer some suggestions to further improve the industry quality and achieve industry upgrading.Methods The national strategies for new infrastructure as well as the underlying logic for enterprise digital transformation were analyzed to provide the outlook on the digital transformation trend of the pharmaceutical distribution industry.Results and Conclusion In the future,the pharmaceutical distribution industry shall transform the pattern,channel,management and control,and experience in the entire business chain in a digital way by focusing on connection efficiency,data efficiency and decision-making efficiency. 展开更多
关键词 pharmaceutical distribution digital transformation new infrastructure TREND
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Brain Functional Network Generation Using Distribution-Regularized Adversarial Graph Autoencoder with Transformer for Dementia Diagnosis 被引量:1
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作者 Qiankun Zuo Junhua Hu +5 位作者 Yudong Zhang Junren Pan Changhong Jing Xuhang Chen Xiaobo Meng Jin Hong 《Computer Modeling in Engineering & Sciences》 SCIE EI 2023年第12期2129-2147,共19页
The topological connectivity information derived from the brain functional network can bring new insights for diagnosing and analyzing dementia disorders.The brain functional network is suitable to bridge the correlat... The topological connectivity information derived from the brain functional network can bring new insights for diagnosing and analyzing dementia disorders.The brain functional network is suitable to bridge the correlation between abnormal connectivities and dementia disorders.However,it is challenging to access considerable amounts of brain functional network data,which hinders the widespread application of data-driven models in dementia diagnosis.In this study,a novel distribution-regularized adversarial graph auto-Encoder(DAGAE)with transformer is proposed to generate new fake brain functional networks to augment the brain functional network dataset,improving the dementia diagnosis accuracy of data-driven models.Specifically,the label distribution is estimated to regularize the latent space learned by the graph encoder,which canmake the learning process stable and the learned representation robust.Also,the transformer generator is devised to map the node representations into node-to-node connections by exploring the long-term dependence of highly-correlated distant brain regions.The typical topological properties and discriminative features can be preserved entirely.Furthermore,the generated brain functional networks improve the prediction performance using different classifiers,which can be applied to analyze other cognitive diseases.Attempts on the Alzheimer’s Disease Neuroimaging Initiative(ADNI)dataset demonstrate that the proposed model can generate good brain functional networks.The classification results show adding generated data can achieve the best accuracy value of 85.33%,sensitivity value of 84.00%,specificity value of 86.67%.The proposed model also achieves superior performance compared with other related augmentedmodels.Overall,the proposedmodel effectively improves cognitive disease diagnosis by generating diverse brain functional networks. 展开更多
关键词 Adversarial graph encoder label distribution generative transformer functional brain connectivity graph convolutional network DEMENTIA
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基于改进Transformer的变电站复杂场景下电力设备分割 被引量:1
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作者 李洋 朱春山 +4 位作者 张建亮 高伟 薛泓林 马军伟 温志芳 《太原理工大学学报》 北大核心 2024年第1期57-65,共9页
【目的】变电站电力设备种类多设备之间连接关系复杂,普遍存在设备位置和图像对比较为单一,实际应用中只能获得有限数量的目标图像和标记以及传统方式分割带来的电力设备图像分割精度不够的问题,将卷积神经网络(Convolution Neural Netw... 【目的】变电站电力设备种类多设备之间连接关系复杂,普遍存在设备位置和图像对比较为单一,实际应用中只能获得有限数量的目标图像和标记以及传统方式分割带来的电力设备图像分割精度不够的问题,将卷积神经网络(Convolution Neural Network,CNN)与Transformmer结合组成新模型进行变电站电力设备的分割,提出了一种基于编解码器结构的新型SE-Transfomer(Substation Equipment Transformer)网络。【方法】为了获取局部上下文信息,编码器首先利用CNN提取空间特征图。同时,对特征图进行了精心改造,多尺度特征输入进行全局特征建模。该解码器利用Transformer提取全局深层特征,并进行逐步上采样来预测详细的分割图。SE-Transfomer在山西省梁家庄变电站数据集上进行广泛实验,其纵向结果的Dice系数(Dice)、召回率(Recall)、特异度(Specificity)和均方根误差(RMSE)分别为89.31%,90.52%,89.62%和11.32.【结果】结果表明,SE-Transfomer在变电站电力设备的扫描上获得了与以往最先进的分割方法相当或更高的结果。 展开更多
关键词 transformer CNN 图像分割 电力设备 变电站
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Mitigation of Transients in Capacitor Coupled Substations Using Traditional RLC Filter Techniques
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作者 Sinqobile Wiseman Nene Bolanle Tolulope Abe Agha Francis Nnachi 《Journal of Power and Energy Engineering》 2024年第5期60-75,共16页
This article presents an extensive examination and modeling of Capacitor Coupled Substations (CCS), noting some of their inherent constraints. The underlying implementation of a CCS is to supply electricity directly f... This article presents an extensive examination and modeling of Capacitor Coupled Substations (CCS), noting some of their inherent constraints. The underlying implementation of a CCS is to supply electricity directly from high-voltage (HV) transmission lines to low-voltage (LV) consumers through coupling capacitors and is said to be cost-effective as compared to conventional distribution networks. However, the functionality of such substations is susceptible to various transient phenomena, including ferroresonance and overvoltage occurrences. To address these challenges, the study uses simulations to evaluate the effectiveness of conventional resistor-inductor-capacitor (RLC) filter in mitigating hazardous overvoltage resulting from transients. The proposed methodology entails using standard RLC filter to suppress transients and its associated overvoltage risks. Through a series of MATLAB/Simulink simulations, the research emphasizes the practical effectiveness of this technique. The study examines the impact of transients under varied operational scenarios, including no-load switching conditions, temporary short-circuits, and load on/off events. The primary aim of the article is to assess the viability of using an established technology to manage system instabilities upon the energization of a CCS under no-load circumstances or in case of a short-circuit fault occurring on the primary side of the CCS distribution transformer. The findings underscore the effectiveness of conventional RLC filters in suppressing transients induced by the CCS no-load switching. 展开更多
关键词 Capacitor Coupled substation System Modeling FERRORESONANCE RLC filters Power Electronics Transients Capacitor Voltage transformers Transmission Lines
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基于CNN-Swin Transformer的分布式超宽带雷达人体动作识别
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作者 张丽丽 贾德振 +1 位作者 潘天鹏 刘彦娟 《电讯技术》 北大核心 2024年第6期830-839,共10页
针对传统雷达人体动作识别方法中特征提取能力不足和上下文建模困难的问题,提出了一种结合卷积神经网络(Convolutional Neural Network, CNN)和Swin Transformer的网络模型,用于有效识别分布式脉冲超宽带雷达数据中的人体动作。通过多... 针对传统雷达人体动作识别方法中特征提取能力不足和上下文建模困难的问题,提出了一种结合卷积神经网络(Convolutional Neural Network, CNN)和Swin Transformer的网络模型,用于有效识别分布式脉冲超宽带雷达数据中的人体动作。通过多分支的CNN对多个雷达的多个谱图、雷达数据的幅度和相位等特征进行提取和融合,利用Swin Transformer模块的多层自注意力机制对生成的特征映射进行上下文建模,提取具有高级语义信息的特征。采用代尔夫特理工大学(Technische Universiteit Delft)公开的数据集进行5折交叉验证,结果表明所提方法能够有效识别9类连续人体动作,识别准确率达到98.2%。 展开更多
关键词 分布式脉冲超宽带雷达 人体动作识别 卷积神经网络(CNN) Swin transformer 特征融合
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基于Transformer的电力故障分类系统探究
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作者 安业腾 史嘉琪 谢青 《仪表技术》 2024年第5期77-80,共4页
配电系统易受外部环境影响,在时空尺度上对潜在故障风险进行分类,对于制订配电系统维护与检修计划,以提高整个配电系统的可靠性至关重要。针对配电系统数据的时空分布不平衡问题,提出了一种基于Transformer模型和注意力机制的配电系统... 配电系统易受外部环境影响,在时空尺度上对潜在故障风险进行分类,对于制订配电系统维护与检修计划,以提高整个配电系统的可靠性至关重要。针对配电系统数据的时空分布不平衡问题,提出了一种基于Transformer模型和注意力机制的配电系统故障风险动态分类模型,旨在对故障结果、故障原因和故障位置进行预测,并结合多种特征属性进行综合分析。实验结果表明,该模型在不同故障的分类任务中表现优异,特别是在捕捉自然因素引起的故障方面展现出显著优势。这项研究不仅进一步证实了自注意力机制和位置编码在提高模型性能方面的核心作用,还充分体现了它们在配电系统数据分析领域中的实用价值。 展开更多
关键词 配电系统 故障风险 分类模型 transformer模型
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Exploring a New Lifetime Distribution for Modelling the Waiting Time of Bank Customers
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作者 Simon A. Ogumeyo Jacob C. Ehiwario Festus C. Opone 《Journal of Applied Mathematics and Physics》 2024年第1期194-209,共16页
The fitting of lifetime distribution in real-life data has been studied in various fields of research. With the theory of evolution still applicable, more complex data from real-world scenarios will continue to emerge... The fitting of lifetime distribution in real-life data has been studied in various fields of research. With the theory of evolution still applicable, more complex data from real-world scenarios will continue to emerge. Despite this, many researchers have made commendable efforts to develop new lifetime distributions that can fit this complex data. In this paper, we utilized the KM-transformation technique to increase the flexibility of the power Lindley distribution, resulting in the Kavya-Manoharan Power Lindley (KMPL) distribution. We study the mathematical treatments of the KMPL distribution in detail and adapt the widely used method of maximum likelihood to estimate the unknown parameters of the KMPL distribution. We carry out a Monte Carlo simulation study to investigate the performance of the Maximum Likelihood Estimates (MLEs) of the parameters of the KMPL distribution. To demonstrate the effectiveness of the KMPL distribution for data fitting, we use a real dataset comprising the waiting time of 100 bank customers. We compare the KMPL distribution with other models that are extensions of the power Lindley distribution. Based on some statistical model selection criteria, the summary results of the analysis were in favor of the KMPL distribution. We further investigate the density fit and probability-probability (p-p) plots to validate the superiority of the KMPL distribution over the competing distributions for fitting the waiting time dataset. 展开更多
关键词 KM-transformation Power Lindley distribution Data Fitting MOMENTS QUANTILES
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Maximum Inner Product Method for Extracting the Path-Loss Parameters in Primary Transformer Substations 被引量:2
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作者 Qiang Li Hongxin Zhang +2 位作者 Tianyi Zheng Xueli Wang Yinghua Lv 《China Communications》 SCIE CSCD 2019年第4期120-129,共10页
In order to deploy short-range wireless communication devices in the primary transformer substation, a Maximum Inner Product(MIP) Method is proposed to extract the path-loss parameters in 110 kV and 220 kV primary tra... In order to deploy short-range wireless communication devices in the primary transformer substation, a Maximum Inner Product(MIP) Method is proposed to extract the path-loss parameters in 110 kV and 220 kV primary transformer substations. The maximum inner product of the testing data is calculated to find out the loss index n and the standard deviation σ, and then the pathloss models can be set up. By comparing the MIP with Minimum Mean Square estimation(MMSE) and Cumulative Sum(CUSUM), MIP can match the measured values best. In order to apply the MIP path-loss model, under the initial signal to noise ratio(SNR) at 5 dB and 10 dB, a ZigBee simulation system is constructed to validate the situation that bit error rate(BER) varies with distance. And the ZigBee devices with 5 units are tested in a 220 kV primary transformer substation. The result of the test proves that the path-loss model is accurate. 展开更多
关键词 PRIMARY transformer substation path-loss ZigBee
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Reduction of Vibration Noise for Amorphous Metal Alloy Core Distribution Transformer 被引量:3
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作者 刘道生 杜伯学 +3 位作者 张建功 徐秋元 祁治海 郭英 《Transactions of Tianjin University》 EI CAS 2015年第4期289-298,共10页
To understand the vibration noise behaviors of amorphous metal alloy core distribution transformer(AMACDT), a 10 k VA prototype was tested under no-load and short-circuit conditions, respectively. The vibration charac... To understand the vibration noise behaviors of amorphous metal alloy core distribution transformer(AMACDT), a 10 k VA prototype was tested under no-load and short-circuit conditions, respectively. The vibration characteristics were described when rated voltage was applied to the secondary side, and the primary side was connected with different load resistances. The largest amplitude positions on the upper bracket and tank surfaces were recorded by vibration sensors arranged on the surface. A data-acquisition platform was set up for signal measurement. The vibration amplitude related to frequency was discussed, and experimental results indicated that the position with the largest amplitude accrued in the middle of the upper bracket and tank surface, at phases a and c, respectively. The experimental results suggest that magnetostrictive and electrodynamic forces play a major role in exciting the vibration noise. At the same time, some rib-reinforcements were welded on the upper bracket and tank surfaces to lessen the vibration energy, which reduced the noise. 展开更多
关键词 distribution transformer MAGNETOSTRICTION electrodynamic FORCE AMORPHOUS metal CORE VIBRATION noise transmission
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A modified lumped parameter model of distribution transformer winding 被引量:5
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作者 Qingqing Ding Yao Yao +5 位作者 Bingqian Wang Jingwei Fu Wei Zhang Chao Zeng Xiaoping Li Stanimir Valtchev 《Global Energy Interconnection》 2020年第2期158-165,共8页
The modelling of the distribution transformer winding is the starting point and serves as important basis for the transformer characteristics analysis and the lightning pulse response prediction.A distributed paramete... The modelling of the distribution transformer winding is the starting point and serves as important basis for the transformer characteristics analysis and the lightning pulse response prediction.A distributed parameters model can depict the winding characteristics accurately,but it requires complex calculations.Lumped parameter model requires less calculations,but its applicable frequency range is not wide.This paper studies the amplitude-frequency characteristics of the lightning wave,compares the transformer modelling methods and finally proposes a modified lumped parameter model,based on the above comparison.The proposed model minimizes the errors provoked by the lumped parameter approximation,and the hyperbolic functions of the distributed parameter model.By this modification it becomes possible to accurately describe the winding characteristics and rapidly obtain the node voltage response.The proposed model can provide theoretical and experimental support to lightning protection of the distribution transformer. 展开更多
关键词 Wide band frequency response distributed parameter model Lumped parameter model distribution transformer Lightning protection
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Research on power electronic transformer applied in AC/DC hybrid distribution networks 被引量:15
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作者 Yiqun Miao Jieying Song +6 位作者 Haijun Liu Zhengang Lu Shufan Chen Chun Ding Tianzhi Cao Linhai Cai Yuzhong Gong 《Global Energy Interconnection》 2018年第3期396-403,共8页
The AC/DC hybrid distribution network is one of the trends in distribution network development, which poses great challenges to the traditional distribution transformer. In this paper, a new topology suitable for AC/D... The AC/DC hybrid distribution network is one of the trends in distribution network development, which poses great challenges to the traditional distribution transformer. In this paper, a new topology suitable for AC/DC hybrid distribution network is put forward according to the demands of power grid, with advantages of accepting DG and DC loads, while clearing DC fault by blocking the clamping double sub-module(CDSM) of input stage. Then, this paper shows the typical structure of AC/DC distribution network that is hand in hand. Based on the new topology, this paper designs the control and modulation strategies of each stage, where the outer loop controller of input stage is emphasized for its twocontrol mode. At last, the rationality of new topology and the validity of control strategies are verified by the steady and dynamic state simulation. At the same time, the simulation results highlight the role of PET in energy regulation. 展开更多
关键词 AC/DC hybrid distribution network Power electronic transformer(PET) Clamping double sub-module(CDSM) Energy router
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Design Of MV/LV Substation Transformer 被引量:1
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作者 Sabir MESSALTI Fares Zitouni Issam Griche 《Engineering(科研)》 2013年第1期20-25,共6页
A substation is a part of an electrical generation, transmission, and distribution system. Substations generally have switching, protection and control equipment, and transformers. The low voltage distribution network... A substation is a part of an electrical generation, transmission, and distribution system. Substations generally have switching, protection and control equipment, and transformers. The low voltage distribution networks are supplied from MV/LV substation transformer that represent the last step of bringing transformation to the? low voltage and ensuring the? protection and monitoring of the network. There are three types of MV/LV substation: pole-mounted transformer substation, the substation in an envelope and substation in masonry. This paper presents a general description for different MV/LV substation and a methodology to design the various elements making up the public distribution substation (choice of the emplacement, engineering, power transformer, choice of MV cells, circuit breakers, fuses, disconnect? switch, conductors,...etc). 展开更多
关键词 substation transformer MV cells substation in MASONRY pole-mounted transformer substation.
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A Maintenance Optimzation Policy for an Electric Power Distribution System: Case of the HV/MV Substations 被引量:1
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作者 Morad Mahmoudi Abdellah El Barkany Ahmed El Khalfi 《Engineering(科研)》 2014年第5期236-253,共18页
Today, in the modern era, and under the pressure of rapid development around the kingdom regions, electric utilities are confronted with a myriad of challenges that include aging infrastructure, enhanced expectation o... Today, in the modern era, and under the pressure of rapid development around the kingdom regions, electric utilities are confronted with a myriad of challenges that include aging infrastructure, enhanced expectation of reliability, reduced cost, and coping effectively with uncertainties and changing regulation requirements. Indeed, for distribution systems, HV/MV substations represent a complex and critical physical asset that requires a careful evaluation of their maintenance practices aiming at more cost-effective tasks. The first concern of the electric power distribution company in Morocco is the optimization of the distribution network maintenance scheduling, to minimize system operating costs and ensure that the system is running most economically. There is significant pressure on power providers for greater system reliability and improvement of customer satisfaction, while similar emphasis is placed on cost reduction. These cost reductions focus on reducing operating and maintenance expenses, and minimizing investments in new plants and equipment. However, the present of the electricity distribution, influenced by a number of technical restrictions and strict regulatory requirements to meet, leads distribution utilities to search new ways of optimizing the maintenance management, make an effort to maximize profit by reducing their electricity supply and operation costs while maintaining their reliability, developing more effective activities, with lower costs. Furthermore, maximal HV/MV substation asset value and minimal maintenance cost are typical economic objectives of the electric utilities. The optimization of maintenance is one possible technique to reduce maintenance costs while improving reliability and utilities need to implement new strategies for more effective maintenance techniques and Asset Management (AM) methods programs to manage inspections and maintenance activities in order to control HV/MV substation equipment conditions. However, development of strategies to make sound decisions in order to effectively improve equipment and system reliability while meeting constraints such as a maintenance budget is a challenge. Finally, this paper describes the application of a new approach based Reliability Centered Maintenance (RCM) methodology to optimize maintenance resources and to the development of maintenance plan for HV/MV distribution substations. For this purpose, a case study was performed on the equipment of power distribution systems for the benefit of a holding company (ONEE Electricity Distribution) in Morocco. The present study was conducted in Oujda Exploitation Maintenance Service (OEXMS), in charge of operation and maintenance of distribution networks. 展开更多
关键词 HV/MV distribution substationS Maintenance Strategy RCM Optimization ASSET Management
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Adjustment of Model Parameters to Estimate Distribution Transformers Remaining Lifespan 被引量:1
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作者 Victor A. Jimenez Adrian Will +1 位作者 Jorge Gotay Sebastián Rodríguez 《Smart Grid and Renewable Energy》 2018年第9期151-170,共20页
Currently, the electrical system in Argentina is working at its maximum capacity, decreasing the margin between the installed power and demanded consumption, and drastically reducing the service life of transformer su... Currently, the electrical system in Argentina is working at its maximum capacity, decreasing the margin between the installed power and demanded consumption, and drastically reducing the service life of transformer substations due to overload (since the margin for summer peaks is small). The advent of the Smart Grids allows electricity distribution companies to apply data analysis techniques to manage resources more efficiently at different levels (avoiding damages, better contingency management, maintenance planning, etc.). The Smart Grids in Argentina progresses slowly due to the high costs involved. In this context, the estimation of the lifespan reduction of distribution transformers is a key tool to efficiently manage human and material resources, maximizing the lifetime of this equipment. Despite the current state of the smart grids, the electricity distribution companies can implement it using the available data. Thermal models provide guidelines for lifespan estimation, but the adjustment to particular conditions, brands, or material quality is done by adjusting parameters. In this work we propose a method to adjust the parameters of a thermal model using Genetic Algorithms, comparing the estimation values of top-oil temperature with measurements from 315 kVA distribution transformers, located in the province of Tucumán, Argentina. The results show that, despite limited data availability, the adjusted model is suitable to implement a transformer monitoring system. 展开更多
关键词 distribution transformer Thermal Model transformer LIFESPAN Parameters Adjustment GENETIC ALGORITHMS
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Research on the Seismic-Geological Conditions for a Large Transformer Substation-A Case Study in the Shimian Region,Sichuan Province 被引量:1
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作者 He Yulin He Honglin Li Yong 《Earthquake Research in China》 2007年第3期304-317,共14页
A seismic-geological disaster can obviously affect an engineering site in three aspects:the first is ground faulting caused by the earthquake;the second is strong ground motion;the third is geological disasters such a... A seismic-geological disaster can obviously affect an engineering site in three aspects:the first is ground faulting caused by the earthquake;the second is strong ground motion;the third is geological disasters such as landslides,mud-rock flows and liquefaction.Through the case study of selection of the huge transformer substation in the Shimian region of Sichuan Province,this paper proposes that the activity pattern and spatial distribution of faults near the site are crucial factors for evaluating the seismic-geological conditions for the location of huge transformer substations. 展开更多
关键词 Seismic disaster Huge transformer substation Active fault Safe distance Shimian region
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Influence of Series Choke on Damping of Switching Transients in Distribution Transformers 被引量:3
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作者 Marek Florkowski Marek Fulczyk +3 位作者 Wojcicch Piasecki Magdalena Ostrogorksa Pawet Klyrs Jakub Furgat 《高电压技术》 EI CAS CSCD 北大核心 2013年第10期2492-2499,共8页
Distribution transformers operating in modern system grids or in industrial networks are subjected to many switching transients,which may occur due to routine operations,network reconfigurations or as reaction on prot... Distribution transformers operating in modern system grids or in industrial networks are subjected to many switching transients,which may occur due to routine operations,network reconfigurations or as reaction on protection signals.Depending on the network configuration and parameters,such events may lead to external overvoltages and result in additional stresses on the insulation system.This paper presents the influence of a series choke on damping of switching transients in distribution transformers.The impact of the choke is assessed by both amplitude and rise time reduction.The suppression of the transient rise time is shown for a test configuration involving distribution transformers connected to low loss cable lines and a medium voltage breaker.Such phenomena are especially typical for industrial networks where switching operations are very frequent.Both simulation and experiment results are given.Simulation results as well as measurement results confirmed that switching events can lead to high dU/dt and in consequence,can have adverse impacts on insulation system.Voltage escalation during switching event is strongly related with system conditions.The results obtained for presented mitigation method are promising and indicate significant dU/dt reduction as well as number of ignitions and voltage peak value.The protection of distribution transformers with a series choke is a new approach dedicated to environments prone to the occurrence of transients with high steepness.Experimental results show that the application of serial choke with suitable parameters realizes the reduction of dU/dt at the machines terminal from 24 kV/μs to 5 kV/μs,as well as the reduction of voltage peak value from 10 kV to 5 kV.The number of ignitions is also reduced. 展开更多
关键词 配电变压器 扼流圈 瞬变 开关 阻尼 切换操作 网络经营 绝缘系统
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Method for Caution Values Calculation of Dissolved Gases in Transformers Based on Statistical Distribution and Correlation Analysis 被引量:3
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作者 WANG Xuelei LI Qingmin +2 位作者 LI Chengrong YANG Rui GAO Shuguo 《高电压技术》 EI CAS CSCD 北大核心 2013年第8期1960-1965,共6页
Before diagnosed by DGA (dissolved gas analysis) methods, gas caution values, which index the level of gas formation, must be used to evaluate the possibility of incipient faults to reduce the misdiagnosis in the norm... Before diagnosed by DGA (dissolved gas analysis) methods, gas caution values, which index the level of gas formation, must be used to evaluate the possibility of incipient faults to reduce the misdiagnosis in the normal state. However, the calculation of these values is now only based on cumulative percentile method without taking into account operating conditions. To overcome this disadvantage, a new approach to calculate the transformer caution values is presented. This approach is based on statistical distribution and correlation analysis, and it takes the individual variation and fluctuation caused by internal and external factors into consideration. Then 6550 transformer DGA data collected from North China Power Grid are analyzed in this paper. The results show that the volume fraction of TH (total hydrocarbon) approximately obeys normal distribution when the 3-sigma rule is used to calculate its caution value. The volume fraction of CO has a strong positive correlation with oil temperature. For H2, the negative correlation with oil temperature is significant when the volume fraction is not very low. The caution value curves for CO and H2 are obtained by regression analyses. Thus, the gas caution values/curves obtained using the new method are not always constant, but vary with oil temperature, which is an advantage of the proposed method compared with cumulative percentile method. The variation of gas caution values/curves also reflects the influence of the external factors, for instance, va- rying with monitoring time ensures that the gas caution values are always consistent with operating status. 展开更多
关键词 溶解气体分析 统计分布 变压器 相关性分析 计算 体积分数 运行状态 操作条件
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Empirical Thermal Investigation of Oil-Immersed Distribution Transformer under Various Loading Conditions
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作者 Syed Ali Raza Ahsan Ullah +2 位作者 Shuang He Yifeng Wang Jiangtao Li 《Computer Modeling in Engineering & Sciences》 SCIE EI 2021年第11期829-847,共19页
The distribution transformer is the mainstay of the power system.Its internal temperature study is desirable for its safe operation in the power system.The purpose of the present study is to determine direct comprehen... The distribution transformer is the mainstay of the power system.Its internal temperature study is desirable for its safe operation in the power system.The purpose of the present study is to determine direct comprehensive thermal distribution in the distribution transformers for different loading conditions.To achieve this goal,the temperature distribution in the oil,core,and windings are studied at each loading.An experimental study is performed with a 10/0.38 kV,10 kVA oil–immersed transformer equipped with forty–two PT100 sensors(PTs)for temperature measurement installed inside during its manufacturing process.All possible locations for the hottest spot temperature(HST)are considered that made by finite element analysis(FEA)simulation and losses calculations.A resistive load is made to achieve 80%to 120%loading of the test transformer for this experiment.Working temperature is measured in each part of the transformer at all provided loading conditions.It is observed that temperature varies with loading throughout the transformer,and a detailed map of temperature is obtained in the whole test transformer.From these results,the HST stays in the critical section of the primary winding at all loading conditions.This work is helpful to understand the complete internal temperature layout and the location of the HST in distribution transformers. 展开更多
关键词 distribution transformer direct temperature measurement sensor location loading conditions hottest spot temperature thermal distribution
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Low-loss B18R065 and B20R070 grain oriented electrical steels for grade 1 energy efficiency distribution transformers
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作者 MA Changsong 《Baosteel Technical Research》 CAS 2017年第3期30-35,共6页
To reduce distribution transformer losses and carbon dioxide emissions, in recent years, the major countries in the world have issued mandatory standards for high-energy efficiency in distribution transformers. In 201... To reduce distribution transformer losses and carbon dioxide emissions, in recent years, the major countries in the world have issued mandatory standards for high-energy efficiency in distribution transformers. In 2013,China has carried out a new standard GB 20052-2013. To meet the update of the standard and energy efficiency,it is important to enhance the magnetic properties of core materials. The new products B18R065 and B20R070 which are developed by Baosteel, are successfully used for grade 1 energy efficiency distribution transformers. And Baosteel becomes one of the companies which can supply both the 0.20 mm and the 0.18 mm gauge grain oriented electrical steels (GOES) in the world. The development principle, material properties, and transformer performance of B18R065 and B20R070 were introduced,which were expected to be a useful reference for materials selection by transformer manufacturers. 展开更多
关键词 B18R065 B20R070 grain oriented electrical steel (GOES) distribution transformer
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The Investigation of Replacing Ceramic Bushings with Silicon Bushings in the Distribution Transformers
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作者 Maryam Amirbandeh Abdol Amir Yaghoti Gholam-Reza Sharifi-Tameh 《Journal of Surface Engineered Materials and Advanced Technology》 2014年第6期319-325,共7页
In recent years, the deficiencies of ceramic insulators along with their high maintenance costs have resulted in the replacement of ceramic insulators with silicon type in the pollution area. This idea has been employ... In recent years, the deficiencies of ceramic insulators along with their high maintenance costs have resulted in the replacement of ceramic insulators with silicon type in the pollution area. This idea has been employed for more than two decades in the polluted areas. Humidity of the weather in the south of Iran and the presence of pollutants in the air have made special conditions for construction and maintenance of some equipment including transformer bushings. Usual ceramic bushings, due to their ability in absorbing pollution and the rapid reduction of creepage distance (in a limited time period), have reduced transformer disconnection severely as a result of earth fault. Additionally, they are costly to be washed regularly. Therefore, using intelligent materials in designing bushing can increase the reliability of network and consequently reduction of costs. In this regard, this paper investigates the use of silicon bushings in the distribution systems and proposes operational ideas for the optimal operation of these devices in the polluted areas. The sample bushing was evaluated based on the IEC60137 standard test. 展开更多
关键词 Ceramic BUSHING SILICON BUSHING distribution transformer INSULATOR POLLUTION
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