At present, lightning is one of the 10 natural disasters, and it is also the top environmental factor of power interruption. It often causes huge losses to the electric system. The Wuhan High Voltage Institute of the ...At present, lightning is one of the 10 natural disasters, and it is also the top environmental factor of power interruption. It often causes huge losses to the electric system. The Wuhan High Voltage Institute of the State Grid Corporation of China and Huazhong University of Science and Technology have been researching and developing lightning location systems （LLSs） since the late 1980s. In the mid-1990s, a lightning detection network was created in 29 provinces and cities in China. It is primarily applied to rapidly find lightning accidents, which greatly reduces power interruption. Also, it ensures high efficiency and safe operation of the electricity system. Remarkable benefit is achieved. China＇s LLS went through an ＂orientation positioning - time difference positioning - integrated positioning＂ development process. The positioning precision, detection efficiency, degree of automation, practicability and applied range are improved. Also, a lightning information system plan of the national network has been implemented, which services the whole society.展开更多
This article focuses on the aggression of lightning overload on the equipment of the electrical network of sites where storm activity is very dense;and the electrocution of people located in the direct environment of ...This article focuses on the aggression of lightning overload on the equipment of the electrical network of sites where storm activity is very dense;and the electrocution of people located in the direct environment of the high-voltage substation during the flow of lightning current to the ground through the ground socket. The modeling of the flow circuit of the shock wave consisting of guard wire, lightning arrester and ground socket couple to the transformer of the high voltage substations, thanks to the approach of a servo block, led to the synthesis of a PID regulator (corrector) whose action is to reject the effects of the overvoltage on the network equipment and to significantly reduce or even cancel the effects of the step or touch voltage due to the distribution of the potential around the ground socket;and thus improve the quality of service of the high-voltage transmission and distribution electricity network, especially in stormy times.展开更多
Based on lightning location data of lightning monitoring network in Guizhou Province in recent eight years,the effective detection radius of a station and the effective detection range of lightning monitoring network ...Based on lightning location data of lightning monitoring network in Guizhou Province in recent eight years,the effective detection radius of a station and the effective detection range of lightning monitoring network in Guizhou Province were analyzed. The results show that the effective detection radius of a lightning monitoring sub-station in Guizhou Province is 160 km; some counties in the southwest,northwest and northeast of Guizhou were not detected. To improve the detector efficiency of lightning monitoring network in Guizhou Province,it is suggested that nine sub-stations should be built in Weining,Shuicheng,Qinglong,Pingtang,Rongjiang,Yuping,Songtao,Tongren and Renhuai,so that the effective detection efficiency will reach more than 95%.展开更多
双有源桥变换器因其优异的功率密度和双向功率传输能力,在众多工业应用中得到广泛关注。随着电力电子设备对能效和可靠性要求的不断提高,双有源桥变换器的电流应力已成为衡量其性能的关键指标之一。过大的电流应力不仅会导致功率器件损...双有源桥变换器因其优异的功率密度和双向功率传输能力,在众多工业应用中得到广泛关注。随着电力电子设备对能效和可靠性要求的不断提高,双有源桥变换器的电流应力已成为衡量其性能的关键指标之一。过大的电流应力不仅会导致功率器件损耗增加,系统效率下降,还会影响变换器的可靠性和使用寿命。针对上述问题,提出了一种基于TabNet-LN-LSTM协同预测与粒子群优化的电流应力优化方法。该方法通过利用TabNet和层归一化长短期记忆神经网络(Long-short term memory neural network with layer normalization,LN-LSTM)协同构建电感电流时序预测模型,并结合粒子群优化算法对双有源桥变换器在不同运行工况下的电流应力进行优化。通过算法试验和硬件试验证明,所提方法不仅能够精确预测电感电流波形,其预测波形与硬件实测波形相比,其平均绝对误差仅为0.3525,决定系数高达97.17%;同时,能够有效降低双有源桥变换器的电流应力,进一步提升系统的整体效能和可靠性。展开更多
近年来区块链发展迅速,交易频率低成为限制区块链进一步发展的障碍。闪电网络作为解决区块链交易频率问题的最优解决方案之一,具有确认时间短、费用低的优点;但也存在着通道容量低、路由代价大、通道易发生拥堵的问题。现有优化方案多...近年来区块链发展迅速,交易频率低成为限制区块链进一步发展的障碍。闪电网络作为解决区块链交易频率问题的最优解决方案之一,具有确认时间短、费用低的优点;但也存在着通道容量低、路由代价大、通道易发生拥堵的问题。现有优化方案多是采用第三方托管,延长交易等待时间,但不能从根源解决通道拥堵问题。针对上述问题,文中提出了一种新的闪电网络优化方案。首先在闪电网络内设置超级节点,并赋予超级节点代币用于相互构建通道,用户通过Ethereum Request for Comment标准将比特币转化为代币进入闪电网络;其次提出逃逸值概念,用户节点通过逃逸值计算选择加入一个超级节点;最后改进landmark算法对网络通道进行修剪,提升网络可扩展性,解决通道拥堵问题。仿真结果表明,此方案对闪电网络内交易量较大时的网络拥堵、路径寻优时间长等问题有良好效果。展开更多
Electrical characteristics of an isolated supercell storm observed on 13 June 2014 over Beijing were investigated using lightning data obtained from the Beijing Lightning Network,radar reflectivity,and hydrometeor ret...Electrical characteristics of an isolated supercell storm observed on 13 June 2014 over Beijing were investigated using lightning data obtained from the Beijing Lightning Network,radar reflectivity,and hydrometeor retrievals during the 6-h lifetime.Positive cloud-to-ground(+CG)lightning took a high percentage of CG lightning.Before and during a hail event,+CG lightning was more frequent than negative cloud-to-ground(-CG)lightning,except that+CG lightning took a high percentage at the beginning and in the dissipating stage.After the hail event ended,-CG lightning dominated and reached its maximum value.An analysis of hydrometeors retrieved by X-band polarimetric radar revealed that the discharge concentrated in the convective region with graupel particles and hailstones,whereas graupel,snow and ice crystals in the stratiform region.Lightning radiation sources were located mainly in the convective region,some of which were distributed along a gradient of radar reflectivity from the convective region to the stratiform region.The indication is that the supercell demonstrated an inverted tripole charge structure before the hail event,which converted to a normal tripole structure after the hail event.展开更多
A back-propagation neural network （BPNN） was used to establish relationships between the shortrange （0-3-h） rainfall and the predictors ranging from extrapolative forecasts of radar reflectivity, satelliteestimate...A back-propagation neural network （BPNN） was used to establish relationships between the shortrange （0-3-h） rainfall and the predictors ranging from extrapolative forecasts of radar reflectivity, satelliteestimated cloud-top temperature, lightning strike rates, and Nested Grid Model （NGM） outputs. Quan- titative precipitation forecasts （QPF） and the probabilities of categorical precipitation were obtained. Results of the BPNN algorithm were compared to the results obtained from the multiple linear regression algorithm for an independent dataset from the 1999 warm season over the continental United States. A sample forecast was made over the southeastern United States. Results showed that the BPNN categorical rainfall forecasts agreed well with Stage Ⅲ observations in terms of the size and shape of the area of rainfall. The BPNN tended to over-forecast the spatial extent of heavier rainfall amounts, but the positioning of the areas with rainfall ≥25.4 mm was still generally accurate. It appeared that the BPNN and linear regression approaches produce forecasts of very similar quality, although in some respects BPNN slightly outperformed the regression.展开更多
In recent years,along with the rapid expansion of power grids,the increasing complication of grid structures,and the development of smart grids and energy technologies,the lightning protection of power grids becomes i...In recent years,along with the rapid expansion of power grids,the increasing complication of grid structures,and the development of smart grids and energy technologies,the lightning protection of power grids becomes increasingly prominent.Power grids of China have acquired significant achievements on lightning protection technologies,which are reviewed in this paper.A technical route of lightning protection is introduced in detail; it allows us to find problems through detection and measurement of lightning,to analyze problems through evaluation and simulation of lightning,to solve problems through lightning protection measures,and to prevent problems through hazard risk warning of lightning.Following the route,the technical breakthroughs of these four aspects in China are presented,including the chinese lightning detection network(CLDN),natural lightning observations,lightning faults detection at transmission lines,lightning current measurements,progresses in lightning distribution maps,lightning fault replays,lightning hazard risk evaluations,and lightning simulated experiments,as well as novel lightning protection measures.The practical devices and systems corresponding to the technologies mentioned above are also introduced and discussed.Due to the progress of lightning protection technologies in recent years,despite the rapidly growing length of transmission lines in China,the lightning accident rate is controlled at a certain level.展开更多
Over the past 10 years,lightning disaster has caused a large number of casualties and considerable economic loss worldwide.Lightning poses a huge threat to various industries.In an attempt to reduce the risk of lightn...Over the past 10 years,lightning disaster has caused a large number of casualties and considerable economic loss worldwide.Lightning poses a huge threat to various industries.In an attempt to reduce the risk of lightning-caused disaster,many scholars have carried out in-depth research on lightning.However,these studies focus primarily on the lightning itself and other meteorological elements are ignored.In addition,the methods for assessing the risk of lightning disaster fail to give detailed attention to regional features(lightning disaster risk).This paper proposes a grid-based risk assessment method based on data from multiple sources.First,this paper considers the impact of lightning,the population density,the economy,and geographical environment data on the occurrence of lightning disasters;Second,this paper solves the problem of imbalanced lightning disaster data in geographic grid samples based on the K-means clustering algorithm;Third,the method calculates the feature of lightning disaster in each small field with the help of neural network structure,and the calculation results are then visually reflected in a zoning map by the Jenks natural breaks algorithm.The experimental results show that our method can solve the problem of imbalanced lightning disaster data,and offer 81%accuracy in lightning disaster risk assessment.展开更多
Visualizing lightning location data is necessary in analyzing and researching lightning activity patterns.This article uses C#and the cross-platform.NET framework to develop a lightning location data analysis class li...Visualizing lightning location data is necessary in analyzing and researching lightning activity patterns.This article uses C#and the cross-platform.NET framework to develop a lightning location data analysis class library and the data-driven client to help lightning researchers improve work efficiency by avoiding repeated wheel invention.Lightning Location System Data Analyzer(LLSDA)is a suite of software tools that includes a.NET class library for software developers and a desktop application for end users.It supports a wide range of lightning location data formats,such as the University of Washington Global Lightning Location System(WWLLN)and Beijing Huayun Dongfang ADTD Lightning Location System data format,and maintains scalability.The class library can easily read,parse,and analyze lightning location data,and combined with third-party frameworks can realize grid analysis.The desktop application can be combined with MeteoInfo(a GIS open-source project)for secondary development.展开更多
张衡一号卫星在轨6年积累了海量观测数据,检测其中的闪电哨声波事件(Lightning Whistler,LW)对于分析空间物理环境规律具有重要意义.但现有基于时频图像的方法推理速度过慢,完成任务需约40年.为此,研究首次从音频事件检测的角度提出高...张衡一号卫星在轨6年积累了海量观测数据,检测其中的闪电哨声波事件(Lightning Whistler,LW)对于分析空间物理环境规律具有重要意义.但现有基于时频图像的方法推理速度过慢,完成任务需约40年.为此,研究首次从音频事件检测的角度提出高速的闪电哨声波检测模型WhisNet,将检测的时间成本从40年压缩至54天.方法为以4 s滑动窗截取波形,提取梅尔频谱特征,利用轻量级卷积循环神经网络(CRNN)提取音频事件特征,输出层预测LW事件起始时间和持续时长.基于2020年4月1-10日的感应磁力仪(SCM)数据实验显示,WhisNet检测性能与传统方法相当,但计算量和参数量减少99%,速度提升98%.进一步在2020年5月SCM数据上的应用结果与WGLC(全球闪电气候学和时间序列,WWLLN Global Lightning Climatology and time series)全球闪电密度趋势高度一致,验证了WhisNet在大规模卫星数据处理中的准确性与适用性.研究结果为挖掘其他海量地球空间事件提供了重要参考.展开更多
针对电网中部分变电站面临的老旧接地网改造升级及周边管网系统安全防护问题,在工频接地网分析的基础上,以实际500 kV变电站新建接地网改造工程及220 kV变电站接地网管道杂散电流干扰防护工程为例进行分析。在应用ETAP Power Station及C...针对电网中部分变电站面临的老旧接地网改造升级及周边管网系统安全防护问题,在工频接地网分析的基础上,以实际500 kV变电站新建接地网改造工程及220 kV变电站接地网管道杂散电流干扰防护工程为例进行分析。在应用ETAP Power Station及CDEGS实际测算的4层土壤模型基础上,结合CDEGS接地网仿真软件搭建了新旧地网以及周边金属管道的实际模型。对比分析工频及高频电流下对接地网及其周边构筑的阻性耦合影响,集中考虑雷电流相较于工频短路电流作用于变电站接地网及周边管网系统时的异同点,发现变电站接地网在高频雷电流排泄散流过程中的薄弱环节。结果表明,高频雷电流作用时,会导致电流入地点处地电位急剧升高,并且入地电流幅值逐级衰减很快,对接地网边缘处地电位升影响不大。变电站周边存在金属管道时,由于瞬时电压的升高,极易造成管道绝缘层的局部放电,导致燃气管道绝缘层电位骤降,造成击穿。展开更多
为研究当无线基站通信塔上避雷针遭受雷击时位于闪电通道附近天线的耦合效应,基于CST Studio Suite电磁仿真软件建立闪电通道-通信塔和工作在中国移动通信GSM1800/1900频段下的微带阵列天线的仿真模型。基于闪电回击电磁模型的继后回击...为研究当无线基站通信塔上避雷针遭受雷击时位于闪电通道附近天线的耦合效应,基于CST Studio Suite电磁仿真软件建立闪电通道-通信塔和工作在中国移动通信GSM1800/1900频段下的微带阵列天线的仿真模型。基于闪电回击电磁模型的继后回击过程,研究从天线极化方向讨论天线的雷击耦合特性以及天线单元连接由不同功分器构成的馈电网络进行组阵时阵列天线的雷击耦合特性。发现天线的耦合电压峰值与极化旋转角呈现线性关系,天线在垂直极化下的耦合电压比在水平极化下的耦合电压大得多;同时,对于通信塔上GSM频段的微带阵列天线,阵列天线的耦合电压受到馈电网络的影响,采用由威尔金森功分器构成的馈电网络进行组阵比采用由T型功分器构成的馈电网络进行组阵阵列天线的耦合电压更小。展开更多
Bitcoin has gained widespread acceptance within the cryptocurrency community, and the Lightning network, an innovative and scalable extension of Bitcoin, is demonstrating remarkable advancements in electronic payments...Bitcoin has gained widespread acceptance within the cryptocurrency community, and the Lightning network, an innovative and scalable extension of Bitcoin, is demonstrating remarkable advancements in electronic payments. The Lightning network addresses the historical criticisms of Bitcoin by facilitating rapid transfers at reduced costs, addressing scalability concerns. However, despite its potential, integrating the Lightning network into diverse systems has proven challenging due to inherent system heterogeneity. This study seeks to overcome these challenges by contributing to the effective implementation of a micropayment system, specifically targeting microtransactions involving individuals outside developing countries, with a focus on the diaspora regularly transferring money to their loved ones. Our objective is to establish a decentralized microtransaction system in Burkina Faso, within the broader context of pursuing monetary independence. We have developed and implemented a prototype microtransaction system, leveraging a transfer application that combines the Lightning network blockchain and mobile money. This unique solution not only integrates local African currencies but also enables direct payments for services and goods at local establishments, fostering economic inclusivity and financial autonomy.展开更多
文摘At present, lightning is one of the 10 natural disasters, and it is also the top environmental factor of power interruption. It often causes huge losses to the electric system. The Wuhan High Voltage Institute of the State Grid Corporation of China and Huazhong University of Science and Technology have been researching and developing lightning location systems （LLSs） since the late 1980s. In the mid-1990s, a lightning detection network was created in 29 provinces and cities in China. It is primarily applied to rapidly find lightning accidents, which greatly reduces power interruption. Also, it ensures high efficiency and safe operation of the electricity system. Remarkable benefit is achieved. China＇s LLS went through an ＂orientation positioning - time difference positioning - integrated positioning＂ development process. The positioning precision, detection efficiency, degree of automation, practicability and applied range are improved. Also, a lightning information system plan of the national network has been implemented, which services the whole society.
文摘This article focuses on the aggression of lightning overload on the equipment of the electrical network of sites where storm activity is very dense;and the electrocution of people located in the direct environment of the high-voltage substation during the flow of lightning current to the ground through the ground socket. The modeling of the flow circuit of the shock wave consisting of guard wire, lightning arrester and ground socket couple to the transformer of the high voltage substations, thanks to the approach of a servo block, led to the synthesis of a PID regulator (corrector) whose action is to reject the effects of the overvoltage on the network equipment and to significantly reduce or even cancel the effects of the step or touch voltage due to the distribution of the potential around the ground socket;and thus improve the quality of service of the high-voltage transmission and distribution electricity network, especially in stormy times.
基金Supported by the Foundation for Young Scholars of Guizhou Meteorological Bureau,China(QN[2012]13)
文摘Based on lightning location data of lightning monitoring network in Guizhou Province in recent eight years,the effective detection radius of a station and the effective detection range of lightning monitoring network in Guizhou Province were analyzed. The results show that the effective detection radius of a lightning monitoring sub-station in Guizhou Province is 160 km; some counties in the southwest,northwest and northeast of Guizhou were not detected. To improve the detector efficiency of lightning monitoring network in Guizhou Province,it is suggested that nine sub-stations should be built in Weining,Shuicheng,Qinglong,Pingtang,Rongjiang,Yuping,Songtao,Tongren and Renhuai,so that the effective detection efficiency will reach more than 95%.
文摘双有源桥变换器因其优异的功率密度和双向功率传输能力,在众多工业应用中得到广泛关注。随着电力电子设备对能效和可靠性要求的不断提高,双有源桥变换器的电流应力已成为衡量其性能的关键指标之一。过大的电流应力不仅会导致功率器件损耗增加,系统效率下降,还会影响变换器的可靠性和使用寿命。针对上述问题,提出了一种基于TabNet-LN-LSTM协同预测与粒子群优化的电流应力优化方法。该方法通过利用TabNet和层归一化长短期记忆神经网络(Long-short term memory neural network with layer normalization,LN-LSTM)协同构建电感电流时序预测模型,并结合粒子群优化算法对双有源桥变换器在不同运行工况下的电流应力进行优化。通过算法试验和硬件试验证明,所提方法不仅能够精确预测电感电流波形,其预测波形与硬件实测波形相比,其平均绝对误差仅为0.3525,决定系数高达97.17%;同时,能够有效降低双有源桥变换器的电流应力,进一步提升系统的整体效能和可靠性。
文摘近年来区块链发展迅速,交易频率低成为限制区块链进一步发展的障碍。闪电网络作为解决区块链交易频率问题的最优解决方案之一,具有确认时间短、费用低的优点;但也存在着通道容量低、路由代价大、通道易发生拥堵的问题。现有优化方案多是采用第三方托管,延长交易等待时间,但不能从根源解决通道拥堵问题。针对上述问题,文中提出了一种新的闪电网络优化方案。首先在闪电网络内设置超级节点,并赋予超级节点代币用于相互构建通道,用户通过Ethereum Request for Comment标准将比特币转化为代币进入闪电网络;其次提出逃逸值概念,用户节点通过逃逸值计算选择加入一个超级节点;最后改进landmark算法对网络通道进行修剪,提升网络可扩展性,解决通道拥堵问题。仿真结果表明,此方案对闪电网络内交易量较大时的网络拥堵、路径寻优时间长等问题有良好效果。
基金supported by the National Natural Science Foundation of China(Grant Nos.41875007 and 41630425)the Special Fund for Meteorology-Scientific Research in the Public Interest(Grant No.GYHY201506004)the 2018 Open Research Program of the State Key Laboratory of Severe Weather(Grant No.2018LASWB06)。
文摘Electrical characteristics of an isolated supercell storm observed on 13 June 2014 over Beijing were investigated using lightning data obtained from the Beijing Lightning Network,radar reflectivity,and hydrometeor retrievals during the 6-h lifetime.Positive cloud-to-ground(+CG)lightning took a high percentage of CG lightning.Before and during a hail event,+CG lightning was more frequent than negative cloud-to-ground(-CG)lightning,except that+CG lightning took a high percentage at the beginning and in the dissipating stage.After the hail event ended,-CG lightning dominated and reached its maximum value.An analysis of hydrometeors retrieved by X-band polarimetric radar revealed that the discharge concentrated in the convective region with graupel particles and hailstones,whereas graupel,snow and ice crystals in the stratiform region.Lightning radiation sources were located mainly in the convective region,some of which were distributed along a gradient of radar reflectivity from the convective region to the stratiform region.The indication is that the supercell demonstrated an inverted tripole charge structure before the hail event,which converted to a normal tripole structure after the hail event.
文摘A back-propagation neural network （BPNN） was used to establish relationships between the shortrange （0-3-h） rainfall and the predictors ranging from extrapolative forecasts of radar reflectivity, satelliteestimated cloud-top temperature, lightning strike rates, and Nested Grid Model （NGM） outputs. Quan- titative precipitation forecasts （QPF） and the probabilities of categorical precipitation were obtained. Results of the BPNN algorithm were compared to the results obtained from the multiple linear regression algorithm for an independent dataset from the 1999 warm season over the continental United States. A sample forecast was made over the southeastern United States. Results showed that the BPNN categorical rainfall forecasts agreed well with Stage Ⅲ observations in terms of the size and shape of the area of rainfall. The BPNN tended to over-forecast the spatial extent of heavier rainfall amounts, but the positioning of the areas with rainfall ≥25.4 mm was still generally accurate. It appeared that the BPNN and linear regression approaches produce forecasts of very similar quality, although in some respects BPNN slightly outperformed the regression.
基金Project supported by National Basic Research Program of China （973 Program） （2011CB209400）, National Fligh-tech Research and Developmerit Program of China （863 Program （2011AA040405）, National Natural Science Foundation of China （Ul134106）, 3551 Optics Valley Personal Plan of Wuhan East Lake High-tech Development Zone, Science and Technology Program of SGCC（SG[2009], SG[2013]）.
文摘In recent years,along with the rapid expansion of power grids,the increasing complication of grid structures,and the development of smart grids and energy technologies,the lightning protection of power grids becomes increasingly prominent.Power grids of China have acquired significant achievements on lightning protection technologies,which are reviewed in this paper.A technical route of lightning protection is introduced in detail; it allows us to find problems through detection and measurement of lightning,to analyze problems through evaluation and simulation of lightning,to solve problems through lightning protection measures,and to prevent problems through hazard risk warning of lightning.Following the route,the technical breakthroughs of these four aspects in China are presented,including the chinese lightning detection network(CLDN),natural lightning observations,lightning faults detection at transmission lines,lightning current measurements,progresses in lightning distribution maps,lightning fault replays,lightning hazard risk evaluations,and lightning simulated experiments,as well as novel lightning protection measures.The practical devices and systems corresponding to the technologies mentioned above are also introduced and discussed.Due to the progress of lightning protection technologies in recent years,despite the rapidly growing length of transmission lines in China,the lightning accident rate is controlled at a certain level.
基金the National Key R&D Program of China under grant number 2018YFB1003205by the National Natural Science Foundation of China under grant number U1836208,U1536206,U1836110,61602253 and 61672294+3 种基金by the Startup Foundation for Introducing Talent of NUIST(1441102001002)by the Jiangsu Basic Research Programs-Natural Science Foundation under grant number BK20181407by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)fundby the Postgraduate Research and Innovation Plan Project in Jiangsu Province under grant number KYCX20_0934 and by the Collaborative Innovation Center of Atmospheric Environment and Equipment Technology(CICAEET)fund,China.
文摘Over the past 10 years,lightning disaster has caused a large number of casualties and considerable economic loss worldwide.Lightning poses a huge threat to various industries.In an attempt to reduce the risk of lightning-caused disaster,many scholars have carried out in-depth research on lightning.However,these studies focus primarily on the lightning itself and other meteorological elements are ignored.In addition,the methods for assessing the risk of lightning disaster fail to give detailed attention to regional features(lightning disaster risk).This paper proposes a grid-based risk assessment method based on data from multiple sources.First,this paper considers the impact of lightning,the population density,the economy,and geographical environment data on the occurrence of lightning disasters;Second,this paper solves the problem of imbalanced lightning disaster data in geographic grid samples based on the K-means clustering algorithm;Third,the method calculates the feature of lightning disaster in each small field with the help of neural network structure,and the calculation results are then visually reflected in a zoning map by the Jenks natural breaks algorithm.The experimental results show that our method can solve the problem of imbalanced lightning disaster data,and offer 81%accuracy in lightning disaster risk assessment.
文摘Visualizing lightning location data is necessary in analyzing and researching lightning activity patterns.This article uses C#and the cross-platform.NET framework to develop a lightning location data analysis class library and the data-driven client to help lightning researchers improve work efficiency by avoiding repeated wheel invention.Lightning Location System Data Analyzer(LLSDA)is a suite of software tools that includes a.NET class library for software developers and a desktop application for end users.It supports a wide range of lightning location data formats,such as the University of Washington Global Lightning Location System(WWLLN)and Beijing Huayun Dongfang ADTD Lightning Location System data format,and maintains scalability.The class library can easily read,parse,and analyze lightning location data,and combined with third-party frameworks can realize grid analysis.The desktop application can be combined with MeteoInfo(a GIS open-source project)for secondary development.
文摘张衡一号卫星在轨6年积累了海量观测数据,检测其中的闪电哨声波事件(Lightning Whistler,LW)对于分析空间物理环境规律具有重要意义.但现有基于时频图像的方法推理速度过慢,完成任务需约40年.为此,研究首次从音频事件检测的角度提出高速的闪电哨声波检测模型WhisNet,将检测的时间成本从40年压缩至54天.方法为以4 s滑动窗截取波形,提取梅尔频谱特征,利用轻量级卷积循环神经网络(CRNN)提取音频事件特征,输出层预测LW事件起始时间和持续时长.基于2020年4月1-10日的感应磁力仪(SCM)数据实验显示,WhisNet检测性能与传统方法相当,但计算量和参数量减少99%,速度提升98%.进一步在2020年5月SCM数据上的应用结果与WGLC(全球闪电气候学和时间序列,WWLLN Global Lightning Climatology and time series)全球闪电密度趋势高度一致,验证了WhisNet在大规模卫星数据处理中的准确性与适用性.研究结果为挖掘其他海量地球空间事件提供了重要参考.
文摘针对电网中部分变电站面临的老旧接地网改造升级及周边管网系统安全防护问题,在工频接地网分析的基础上,以实际500 kV变电站新建接地网改造工程及220 kV变电站接地网管道杂散电流干扰防护工程为例进行分析。在应用ETAP Power Station及CDEGS实际测算的4层土壤模型基础上,结合CDEGS接地网仿真软件搭建了新旧地网以及周边金属管道的实际模型。对比分析工频及高频电流下对接地网及其周边构筑的阻性耦合影响,集中考虑雷电流相较于工频短路电流作用于变电站接地网及周边管网系统时的异同点,发现变电站接地网在高频雷电流排泄散流过程中的薄弱环节。结果表明,高频雷电流作用时,会导致电流入地点处地电位急剧升高,并且入地电流幅值逐级衰减很快,对接地网边缘处地电位升影响不大。变电站周边存在金属管道时,由于瞬时电压的升高,极易造成管道绝缘层的局部放电,导致燃气管道绝缘层电位骤降,造成击穿。
文摘为研究当无线基站通信塔上避雷针遭受雷击时位于闪电通道附近天线的耦合效应,基于CST Studio Suite电磁仿真软件建立闪电通道-通信塔和工作在中国移动通信GSM1800/1900频段下的微带阵列天线的仿真模型。基于闪电回击电磁模型的继后回击过程,研究从天线极化方向讨论天线的雷击耦合特性以及天线单元连接由不同功分器构成的馈电网络进行组阵时阵列天线的雷击耦合特性。发现天线的耦合电压峰值与极化旋转角呈现线性关系,天线在垂直极化下的耦合电压比在水平极化下的耦合电压大得多;同时,对于通信塔上GSM频段的微带阵列天线,阵列天线的耦合电压受到馈电网络的影响,采用由威尔金森功分器构成的馈电网络进行组阵比采用由T型功分器构成的馈电网络进行组阵阵列天线的耦合电压更小。
文摘Bitcoin has gained widespread acceptance within the cryptocurrency community, and the Lightning network, an innovative and scalable extension of Bitcoin, is demonstrating remarkable advancements in electronic payments. The Lightning network addresses the historical criticisms of Bitcoin by facilitating rapid transfers at reduced costs, addressing scalability concerns. However, despite its potential, integrating the Lightning network into diverse systems has proven challenging due to inherent system heterogeneity. This study seeks to overcome these challenges by contributing to the effective implementation of a micropayment system, specifically targeting microtransactions involving individuals outside developing countries, with a focus on the diaspora regularly transferring money to their loved ones. Our objective is to establish a decentralized microtransaction system in Burkina Faso, within the broader context of pursuing monetary independence. We have developed and implemented a prototype microtransaction system, leveraging a transfer application that combines the Lightning network blockchain and mobile money. This unique solution not only integrates local African currencies but also enables direct payments for services and goods at local establishments, fostering economic inclusivity and financial autonomy.
