Characteristics of Lightning Activity in Southeast China and its Relation to the Atmospheric Background

Based on the lightning observation data from the Fengyun-4A(FY-4A)Lightning Mapping Imager(FY-4A/LMI)and the Lightning Imaging Sensor(LIS)on the International Space Station(ISS),we extract the“event”type data as the lightning detection results.These observations are then compared with the cloud-to-ground(CG)lightning observation data from the China Meteorological Administration.This study focuses on the characteristics of lightning activity in Southeast China,primarily in Jiangxi Province and its adjacent areas,from April to September,2017–2022.In addition,with the fifth-generation European Centre for Medium-Range Weather Forecasts reanalysis data,we further delved into the potential factors influencing the distribution and variations in lightning activity and their primary related factors.Our findings indicate that the lightning frequency and density of the FY-4A/LMI,ISS-LIS and CG data are higher in southern and central Jiangxi,central Fujian Province,and western and central Guangdong Province,while they tend to be lower in eastern Hunan Province.In general,the high-value areas of lightning density for the FY-4A/LMI are located in inland mountainous areas.The lower the latitude is,the higher the CG lightning density is.High-value areas of the CG lightning density are more likely to be located in eastern Fujian and southeastern Zhejiang Province.However,the high-value areas of lightning density for the ISS-LIS are more dispersed,with a scattered distribution in inland mountainous areas and along the coast of eastern Fujian.Thus,the mountainous terrain is closely related to the high-value areas of the lightning density.The locations of the high-value areas of the lightning density for the FY-4A/LMI correspond well with those for the CG observations,and the seasonal variations are also consistent.In contrast,the distribution of the high-value areas of the lightning density for the ISS-LIS is more dispersed.The positions of the peak frequency of the FY-4A/LMI lightning and CG lightning contrast with local altitudes,primarily located at lower altitudes or near mountainsides.K-index and convective available potential energy(CAPE)can better reflect the local boundary layer conditions,where the lightning density is higher and lightning seasonal variations are apparent.There are strong correlations in the annual variations between the dew-point temperature(Td)and CG lightning frequency,and the monthly variations of the dew-point temperature and CAPE are also strongly correlated with monthly variations of CG lightning,while they are weakly correlated with the lightning frequency for the FY-4A/LMI and ISS-LIS.This result reflects that the CAPE shows a remarkable effect on the CG lightning frequency during seasonal transitions.

Detection Situation and Improvement of Lightning Monitoring Network in Guizhou Province

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%.

LLSDA: Design and Implementation of Lightning Location Data Analysis and Visualization

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.

Development and Application of Lightning Protection Technologies in Power Grids of China

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.

Revision of CG Flash Density Based on Lightning Location Data

Using the data of the Lightning Location System( LLS) over Hubei Province,through the analysis of the distribution characteristics of CG( Cloud-to-Ground) flash density in 2015,it was found that the layout of the detection station had influence on the spatial distribution of lightning.Grid CG flash density data were used to characterize the spatial distribution of the CG flash,and station distance factor was used to characterize the detection station layout. The result showed that there existed negative correlation between density and factor,significant correlation between the density component and the factor for the lightning current amplitude of 5 to 30 kA,and insignificant correlation between >30 kA of density component and factor. So it is necessary to revise the density to eliminate the influence of the station layout. On the basis of the linear regression method and its residual theory,the revision model of the grid CG flash density and the statistical model of relative detection efficiency were established. The result consistency of segment and non-segmented revision of the density was verified. Through the contrastive analysis of theoretical detection efficiency and relative detection efficiency,the feasibility for revision method of CG flash density and the statistical method of relative detection efficiency was also verified.

Instantaneous Real-Time Detection Technology of GLI on FY-4 Geostationary Meteorological Satellite

Lightning is a typical example of an instantaneous random point source target. It has close connection with severe convective phenomena such as a thunderstorm, whose distribution, variation, position and forecasting can be acquired through lightning observation. In this paper, we discuss the way to achieve instantaneous lightning signal intensification and detection from geostationary orbit by using the differences between the lightning signal and the slowly changing background noise such as that of cloud, land and ocean, combining three methods, spectral filtering, spatial filtering and background noise, enabling removal between frames. After six months of operation in orbit, lightning within the coverage of the Geostationary Lightning Imager was effectively detected, strongly supporting the case for shorttime and real-time early warning, forecasting and tracking of severe convective phenomena in China.

考虑雷击与浪涌的气象观测数据质量控制方法

针对气象观测中的异常数据检测和校正效率较低的问题,文中基于BP神经网络提出了一套具有误差修正功能的数据质量控制方法。该方法研究了气象观测传感器的理论及布局,分析了异常数据的来源、分类、检测方法。并在此基础上,通过引入BP神经网络的模型及滑动窗口实现了多种气象异常数据的插值与拟合,从而建立了计及雷击、浪涌现象的气象观测数据修正模型。仿真结果表明,与经典的气象数据质控方法相比,基于BP神经网络的数据质控方法具有更高的数据准确度,且修正效率可达80%以上。

云南省两套闪电定位系统地闪回击参数对比及探测性能分析

根据2017—2020年云南省ADTD二维和VLF/LF三维闪电定位系统观测资料,对比两套系统地闪回击参数分布差异。在实际回击位置和雷电流强度信息难以获得的情况下,研究利用两套系统反演资料对相同回击事件的识别匹配和时空阈值选取方法,分析相对定位偏差。结果表明:两套系统的回击密度、雷电流幅值在滇东、滇西南和滇西北等地的空间分布差异明显,由三维系统得到的回击密度较大,但二维系统雷电流幅值均值更高。两套系统均以单回击地闪占比更高,正地闪中的单回击地闪比重较负地闪更大,三维系统对于0~5 kA负回击小幅值电流的探测效率有所提高。通过采用10km、1 ms的时空阈值匹配窗口,得到两套系统对于同一次回击的相对定位时间差主要集中在0.05 ms内,距离偏差集中在1 km内。系统匹配回击在滇中、滇西南的时空偏差较小,滇西北的偏差较大。从回击极性、相关系数、相对误差、幅值比及幅值累积概率等方面,分析得到两套系统对于相同回击事件的电流强度反演结果一致性较好,验证了应用系统反演资料对于同一回击事件的识别匹配方法是客观可靠的。

供电系统避雷器故障检测与自动切换系统设计

针对供电系统中避雷器容易损坏且人工运维困难的问题,提出一种新型供电系统避雷器故障检测与自动切换方法。该方法利用快速傅里叶变换实时检测电流,利用微控制器进行数据分析并发出控制信号,实现在线检测避雷器故障。通过设计的自动切换避雷器机械结构,可实现备用避雷器逐一自动切换。研发系统样机并开展试验分析,试验结果表明本系统功能可行有效,可实现避雷器故障检测和自动切换。

基于ADTD的FY-4A卫星闪电探测性能分析

为评估风云四号A星(Fengyun-4A,FY-4A)的闪电探测性能,提出了基于星地闪电数据统计特征的匹配方法:选取较大时空窗口,进行星地数据匹配;对匹配数据的时间差和距离差进行概率统计,确定最合适的时空窗口。通过对我国2020年夏季(6—8月)FY-4A和地基闪电定位系统(advanced direction and time-of-arrival detecting system, ADTD)的闪电数据进行统计,确定时间间隔3.4 s,空间经纬度间隔0.6°作为星地数据一致性分析的时空窗口。基于此时空窗口开展了星地闪电数据的对比分析,结果表明,星地数据时间偏差平均值为1.3 s,空间偏差平均值为23.73 km;FY-4A闪电探测效率为19%,FY-4A探测效率具有明显的日变化特征,白天平均探测效率为7%,明显低于夜晚的31.1%,且白天12:00—14:00时探测效率最低,仅为2.3%;FY-4A闪电数据的光辐射强度日变化特征与太阳高度角的变化呈正相关,白天12:00—14:00时光辐射强度最大达到1 391μJ/m2/sr,比夜晚光辐射强度(124μJ/m2/sr)高一个量级,白天只有光辐射较强的闪电才能被FY-4A闪电成像仪(lightning mapping imager, LMI)捕获,进一步解释了白天闪电探测效率低的原因。

物联网技术在海上风电防雷检测平台开发与实现研究

海上风电作为可再生能源的重要组成部分,具有巨大的发展潜力和环境效益。然而,雷电对海上风电系统的影响成为制约海上风电系统可靠性和安全性的重要因素之一。为了有效预防和应对雷电引发的潜在问题,利用物联网技术开发和实现海上风电防雷检测平台具有重要的研究意义和实际价值。文章探索了物联网技术在海上风电防雷检测平台中的应用,通过对雷电数据的采集、分析和预警,为海上风电系统的安全运行提供了科学依据和技术支持。

改进YOLOv5的闪电哨声波轻量化自动检测模型

提出一种改进YOLOv5(You-Only-Look-Once version 5)检测模型YOLOv5-Upgraded.为了更快定位真实边框,该模型将损失函数CIoU (Complete IoU)替换为SIoU(Scylla IoU);同时为了避免网络训练过程中梯度消失、梯度爆炸以及神经元坏死等现象,将激活函数SiLU(Sigmoid-weighted Linear Unit)替换为具有更好梯度流的Mish;在主干网络中插入注意力(Coordinate Attention, CA)机制,帮助模型更精准地识别闪电哨声波,大大降低了漏检率.基于张衡一号感应磁力仪(Search Coil Magnetometer, SCM)数据,以2.4 s时间窗口截取数据,经带通滤波、短时傅里叶变换得到1126张时频图数据集,再经图像增强操作扩充至7882张,其中7091张作为训练集, 791张作为测试集.实验结果表明,基于改进YOLOv5的模型平均精度均值为99.09%,召回率为96.20%,与YOLOv5s相比,分别提升了2.75%和5.07%,与基于时频图的YOLOv3模型相比,平均精度均值和召回率则分别提高了5.89%和9.62%.基于智能语音的LSTM (Long Short Term Memory Networks)闪电哨声波识别模型大小为82.89 MB, YOLOv5-Upgraded仅为13.78 MB,约节省83.38%的内存资源.研究表明改进后的轻量化模型大大降低了闪电哨声波的漏检现象,在测试集中取得了较好结果,并且其轻量化特征易于部署到卫星设备,极大地提高了星载识别的可能性.

基于多维数据对江西省气象部门内防雷检测企业发展对策研究

为研究防雷行政审批与防雷减灾管理改革过程中防雷检测企业的发展情况,通过收集并对比2017-2022年防雷产业相关数据,以江西省体制内外两个防雷检测企业的数据为例,对江西省防雷检测企业的发展情况进行分析,提出集约化发展、发挥行业协会作用、利用互联网思维提高江西省气象部门内防雷检测企业营收的对策建议。

高层建筑防雷检测技术研究

分析、探讨高层建筑雷电危害主要特点、防雷措施及检测技术特点,给出高层建筑尤其是超高层建筑检测中检测基准点的选取方法,从内部防雷、外部防雷、侧击雷防护等方面阐述防雷检测技术的各环节要素及注意细节,提出加强高层建筑防雷设施的日常维护和定期检测。

基于自动化监测的气象站观测场防雷技术研究

针对当前气象站观测场防雷技术采用统一的防雷方案,忽视了气象站观测场内各设备的差异性,导致设备雷击率较高的问题,设计一种基于自动化监测的气象站观测场防雷技术。首先构建气象站观测场雷电幅值自动化监测系统,获取气象站观测场雷电幅值以及过场电压。选择规程法计算设备的反击跳闸率,以此确定现有避雷设备耐雷性能。计算避雷设备保护范围,结合观测场雷电幅值,设定差异化综合防雷技术。实验结果表明:此技术可有效缩减观测场雷电幅值与波动,降低设备雷击率,进一步提升气象观测的安全性。

基于傅里叶变换算法的变电站母线避雷器泄露电流异常检测方法

为降低变电站安全风险为目的,提出基于傅里叶变换算法的变电站母线避雷器泄露电流异常检测方法。利用无线传感器采集变电站母线避雷器运行电流数据后,对变电站母线电流进行平滑处理;去除其内部所含的干扰噪声后,利用基于递推傅里叶变换方法分解得到变电站母线避雷器运行电流内存在的谐波,该谐波即为变电站母线避雷器泄露电流异常检测结果。试验结果表明:对变电站母线避雷器运行电流去噪预处理能力较强,且其检测变电站母线避雷器泄露电流异常能力较强,具备较佳的应用效果。

宜春市防雷检测服务系统的分析与设计

为动态实时掌握企业防雷安装信息,提高宜春市气象部门防雷检测的服务效率和服务质量,设计了宜春市防雷检测服务系统。该系统基于微软公司推出的新一代脚本语言Active Server Page.NET(ASP.NET),整体架构采用B/S形式的两层架构。系统能够显示企业的防雷工程信息,分析出防雷工程不合格的设计,及时给出指导意见;按照检测情况,系统能够跟踪防雷检测报告的进展情况,方便查阅和及时获取报告。

220 kV氧化锌避雷器泄漏电流异常分析

氧化锌避雷器作为保护电网免受过电压侵害的重要设备,在发、输、变、配电系统中应用较为普遍,其安全性能对维护网络可靠运行意义重大,在运氧化锌避雷器缺陷将对系统安全构成严重威胁。针对徐家站220 kV抚徐线氧化锌避雷器泄漏电流异常的危急缺陷,结合工程实践通过试验诊断和解体检查进行原因分析。采用阻性电流测试、红外检测与停电试验相结合的方法,停电进行更换,返厂解体检查发现密封板与防爆板之间密封胶圈密封不严造成内部绝缘受潮,并分别从运行维护和试验角度提出合理化建议,为同类型设备故障诊断和运行维护提供参考。

基于IGWO-SVM的氧化锌避雷器故障检测

为了提高氧化锌避雷器的故障检测精度,文章利用收敛因子非线性变化和莱维飞行策略对灰狼(Grey Wolf Optimization, GWO)算法进行改进,得到收敛性能更好的改进灰狼(Improved Grey Wolf Optimization, IGWO)算法,再采用IGWO算法对支持向量机(Support Vector Machine, SVM)的惩罚系数和核带宽进行优化,建立基于IGWO-SVM的避雷器故障检测模型。利用氧化锌避雷器监测数据进行故障检测实例分析,将IGWO-SVM模型的故障检测结果与现有避雷器故障检测模型的检测结果对比,结果表明,IGWO-SVM模型的检测精度更高,验证了该模型在氧化锌避雷器故障检测方面的优越性。