Analysis on Attenuation Efficiency of Lightning Current by Lightning Interceptor

Lightning interception technology is one of the three core technical systems of regional lightning protection theory.Among them,the omni-directional multi-pulse lightning interceptor(hereinafter referred to as lightning interceptor,the same below)has the ability to attenuate lightning current≥40%and significantly reduce the intensity of the spatial electromagnetic field around the lightning point.In order to explore the attenuation mechanism and effect of lightning interceptor to lightning current,this paper analyzed a lightning stroke process at 16:00 on August 19,2022,and tried to explain the attenuation effect of lightning interceptor to lightning current with the physical parameters of lightning stroke.

Estimation of Lightning-Generated NO_(x) in the Mainland of China Based on Cloud-to-Ground Lightning Location Data

Lightning-generated nitrogen oxides(LNO_(x))have a major influence on the atmosphere and global climate change.Therefore,it is of great importance to obtain a more accurate estimation of LNO_(x).The aim of this study is to provide a reference for the accurate estimation of the total LNO_(x) in the mainland of China based on cloud-to-ground lightning(CG)location data from 2014 to 2018.The energy of each CG flash was based on the number of return strokes per CG flash,the peak current of each return stroke,and the assumed CG breakdown voltage.The energy of intracloud lightning(IC)was based on the estimated frequencies of IC and the assumed energy of each IC flash.Combining the energy of lightning and the number of nitric oxide(NO)molecules produced by unit energy(ρno),the total LNO_(x) production in the mainland of China was determined.The LNO_(x) in the mainland of China estimated in this study is in the range(0.157-0.321)×10^(9) kg per year[Tg(N)yr-1],which is on the high end of other scholars’works.Negative cloud-to-ground lightning(NCG)flashes produce the most moles of NO_(x),while positive cloud-to-ground lightning(PCG)flashes produce the least total moles of NO_(x).The breakdown voltage of PCG is greater than that of IC or NCG,while the latter has a greater output of LNO_(x).

Three Core Technical Systems and Engineering Application of Regional Lightning Protection

Regional lightning protection is a complete theoretical system,mainly including:lightning interception technology(LIPT),lightning strong electromagnetic pulse high-energy absorption technology(MSPD),and regional lightning activity law analysis technology(RLLA).Lightning interception technology uses dispersive waveguide resonant cavity technology to achieve the functions of 46.55 m longer than upward leader of ordinary lightning rod,significantly reducing lightning strike point current by 40%,optimizing space electromagnetic field environment,and effectively intercepting overhead and side lightning strikes,and overcome the limitations of traditional lightning rod.The lightning strong electromagnetic pulse high-energy absorption technology uses distributed parameter balance technology,special disconnector for short circuit current,and parity pairing technology to achieve stronger surge absorption capacity than traditional single pulse SPD and international advanced technical indicators such as timely breaking under power frequency short circuit current,and good energy and time coordination.The analysis technology of regional lightning activity laws accurately identifies lightning strike points through comprehensive analysis of regional lightning activity laws,physical parameters of ion clouds,and the impact on ground electric fields.The three core technology systems complement each other,achieving all-round protection against direct lightning strike and lightning electromagnetic pulse.Several projects achieved zero lightning damage,effectively ensuring the safety of buildings and electronic and electrical equipment in the protected area.

Experimental and analytical investigation on metal damage suffered from simulated lightning currents

The damage of two typical metal materials, Al alloy 3003 and steel alloy Q235 B, subjected to four representative lightning current components are investigated by laboratory and analytical studies to provide fundamental data for lightning protection. The four lightning components simulating the natural lightning consist of the first return stroke, the continuing current of interval stroke, the long continuing current, and the subsequent stroke, with amplitudes 200 k A, 8 k A,400 A, and 100 k A, respectively. The damage depth and area suffered from different lightning components are measured by the ultrasonic scanning system. And the temperature rise is measured by the thermal imaging camera. The results show that, for both Al 3003 and steel Q235 B, the first return stroke component results in the largest damage area with damage depth0.02 mm uttermost. The long continuing current component leads to the deepest damage depth of 3.3 mm for Al 3003 and much higher temperature rise than other components. The correlation analysis between damage results and lightning parameters indicates that the damage depth has a positive correlation with charge transfer. The damage area is mainly determined by the current amplitude and the temperature rise increases linearly with the charge transfer larger.

Current Lightning Risk Assessment in Yantai

The development situation and business processes of lightning risk assessment in Yantai were summarized and analyzed to provide references for the operation of lighting risk assessment. This study aimed to further improve lightning risk assessment and promote the development of lightning risk assessment through practice and discussion.

Testing of Lightning Protective System of a Residential Structure： Comparison of Data Obtained in Rocket-triggered Lightning and Current Surge Generator Experiments

We present a comparison of data obtained during testing of lightning protective system of a residential structure in rocket-triggered lightning experiment at the International Center for Lightning Research and Testing(ICLRT)at Camp Blanding,Florida,and current surge generator experiment at Rzeszow University of Technology in Poland.Three different configurations of LPS were tested in Poland with the dc grounding resistances of the entire system 4.09 Ω(LPS 1a),1.65 Ω(LPS 1b),and 2.88 Ω(LPS 2).For LPS 1a with three ground rods the value of the peak current entering the electrical circuit neutral was about 56% of the injected current peak,and for LPS 1b with two additional ground rods and two 5 m long buried horizontal conductors it was about 16%.For LPS 2 with five ground rods interconnected by a buried loop conductor this ratio was 21%.The current waveshapes in the ground rods differed from the injected current waveshapes and the current waveshapes in other parts of the test system,especially,for poorer-grounding LPS 1a.The surge-generator results are consistent with those of triggered-lightning experiments at Camp Blanding,Florida(DeCarlo et al.,2008 [2]).

Climatology of Lightning Activity in South China and Its Relationships to Precipitation and Convective Available Potential Energy

This study examined lightning activity and its relationship to precipitation and convective available potential energy （CAPE） in South China during 2001-12, based on data from the Guangdong Lightning Location System, the Tropical Rainfall Measuring Mission satellite, and the ERA-Interim dataset. Two areas of high lightning density are identified： one over the Pearl River Delta, and the other to the north of Leizhou Peninsula. Large peak-current cloud-to-ground （LPCCG） lightning （〉75 kA） shows weaker land-offshore contrasts than total CG lightning, in which negative cloud-to-ground （NCG） lightning occurs more prominently than positive cloud-to-ground （PCG） lightning on land, While the frequency of total CG lightning shows a main peak in June and a second peak in August, the LPCCG lightning over land shows only a single peak in June. The ratio of positive LPCCG to total lightning is significantly greater during February-April than during other times of the year. Diurnally, CG lightning over land shows only one peak in the afternoon, whereas CG lightning offshore shows morning and afternoon peaks. The rain yield per flash is on the order of 107-108 kg per flash across the analysis region, and its spatial distribution is opposite to that of lightning density. Our data show that lightning activity over land is more sensitive than that over offshore waters to CAPE. The relationships between lightning activity and both precipitation and CAPE are associated with convection activity in the analysis region.

Analysis of the Spectral Characteristics of Triggered Lightning

The spectra with wavelength range of 390 nm to 660 nm of triggered lightning were observed in Guangdong Area using a slitless spectrograph. The characteristics of the lightning spectra during the initial continuous current and return strokes were analyzed, and the differences between the metal section and air section of the lightning channel were compared. The results showed that the metal spectra were contained in the metal section during the initial continuous current. As for the lightning channel of the return strokes, the line spectra for both the metal section and the air section were identical;neither of the two sections contained the metal spectra, but the relative intensity of its emission spectrum was different. Owing to different radiation mechanisms, the spectral structures and luminance of the two sections were not the same. Combined with the current data, it was found that there was a good positive correlation between the total spectral strength and the transferred charge. The total intensity of the lightning channel spectrum increased with the height of the channel, indicating that the radiation sequence of the lightning channel was different. High temporal resolution observations showed that the spectral line duration could be divided into three categories, in which the lines with higher excitation energy appear first and decay rapidly, while those with lower excitation energy appear later but last longer.

Application of Comprehensive Lightning Interceptor in Highway Toll Station

Expressway toll station is listed by lightning protection experts as one of the five difficult problems in the field of international lightning protection.So far,the direct lightning protection of the expressway toll station is mainly based on the electrical geometry model-rolling ball method.Lightning rod or lightning belt is installed on the high pole lamp of the toll square and the ceiling of the toll island as a flash catching device to intercept lightning.The lightning rod is a section of metal conductor with the tip.From the process of the connection between up leader generated by the lightning rod and down leader of lightning,the lightning rod has the ability to attract the lightning rod,and can prevent lightning strike of the protected objects within a certain range.From the perspective of lightning protection methods and means,lightning protection plays an interception role against lightning discharge,also called interceptor.A large number of practice has proved that the lightning rod plays an important role in protecting the building structure from lightning damage.With the development of electronic information society,the limitations of lightning rod are more and more prominent,resulting in more and more lightning strike accidents.In 2019,China invented a new flash connection device-lightning interceptor that can overcome the limitations of lightning rod and has applied it on expressways,which has achieved remarkable results.In this paper,the physical parameters of lightning receiving process by the lightning interceptor and the lightning rod are compared,and the solution to prevent direct lightning strike at expressway toll station is proposed.

Effectiveness of Lightning Protection Devices

In addition to the conventional Franklin Rod,many non-conventional air terminals are being used as lightning protection devices.As cited in previous works,these non-conventional devices emit space charge in the vicinity of the terminals during the process of lightning stroke.A number of factors affect the performance of these lightning protection devices,among them are geometry and dimension of the devices,location of the device above the ground,height of the cloud above the ground,and polarity of the lightning stroke.The performance of these lightning protection devices has been a topic of discussion by researchers for many years.Some studies focused on the magnitude of emission current from these devices as a criterion to evaluate their performances.The critical flashover voltage(CFO)between the devices and a metal screen simulating cloud can also be used as another criterion to evaluate the performance of the devices.Laboratory measurements were conducted in controlled conditions on different types of lightning protection devices to compare their performance.Four different types of devices were used in the present study:Franklin Rod,TerraStat models TS 100,TS 400,and Spline Ball Ionizer.The study focused on the CFO voltage of the air gap between devices and the metal screen.The CFO voltage was evaluated using standard switching and lightning impulses.The measurements were recorded for positive as well as negative polarity.The air gap between the devices and metal screen was selected at 2 m and 3 m.The results obtained provide a better understanding of the electrical performance of lightning protection devices.

Preliminary Study on the Influence of Communication Station on Lightning Strike Risk in Its Neighboring Region

The communication stations are more easily struck by lightning because of its special geographical position. We proved theoretically that communication station increased the frequency and intensity of lightning strike in its neighboring region, thereby causing the increasing of lightning disaster loss. As long as the emphasis is put on the correct understanding and reasonably taking measures including： draining, grounding, equipo- tential bonding and shielding, it can be completely ensured that building and equipment of communication base station and its neighboring region are safe.

Analysis on Characteristics of Lightning Activity in Heilongjiang Province during 2015-2017

Based on lightning monitoring data obtained by Heilongjiang lightning location network during 2015-2017, total characteristics, current intensity, annual change trend and density distribution characteristics of lightning in Heilongjiang Province in the three years were analyzed by using statistical analysis method. The results showed that total lightning showed an increasing trend in Heilongjiang in recent years, and average intensity of negative lightning was obviously larger than that of positive lightning, and intensity of ground lightning mainly concentrated in 10-50 kA. Thunder and lightning activity of Heilongjiang was mainly in summer and concentrated during June-September. Daily variation of lightning frequency in Heilongjiang showed obvious single-peak-single-valley type, and change trends of positive lightning, negative lightning and total lightning were basically consistent. Frequent occurrence period of lightning mainly concentrated in 13:00-19:00, accounting for 50.6% of total frequency of lightning, and it was key period of lightning defense in Heilongjiang Province. Regional distribution of lightning density had obvious difference, and lightning mainly concentrated in the Greater Khingan Mountains of north Heilongjiang and Harbin, Yichun and Suihua of central Heilongjiang.

The Field Shielding Effect of Mountain on the Lightning Electromagnetic Field

In this paper we have studied the effect of strike to a cone-shaped mountain surrounded by two chains of hills on the lightning vertical electric field and azimuthal magnetic field at different distances, by using two-dimensional finite-difference time-domain (2-D FDTD) method in cylindrical coordinate systems. In order to analyze the electrostatic shielding effect of strike to a cone-shaped mountain surrounded by two chains of hills on the lightning, we chose three mountains, and the left one is stroke by lightning, and the right one is near the obervation site, and the middle one with the top heights increasing from 0 to 2 km is between them. For the observed point, the electrostatic shielding effect of the right one on the lightning vertical electric field is the most serious, and the electric field is much less than that for strike to flat ground level;compared with the electric field, the shielding effect of the right one on the lightning azimuthal magnetic field becomes less, for most cases, the lightning magnetic field at the observed site is larger than that for flat ground cases mainly due to that of the increment caused by strike to the right mountain. With the increase of distance (e.g., 20 km from the lightning strike point), the shielding effect of the right mountain on the lightning field becomes less, because the reflected wave from the right mountain bottom plays a more important role over intermediate ranges, and the far radiation electromagnetic field peak value becomes larger due to such a reflecting wave. Therefore, in the lightning detecting technique, we should pay more attention to the effect caused by chains of hills on the lightning location and the estimation of lightning current peak.

Statistical Analysis on Lightning Characteristics in Hebei Province

By using monitoring data of lightning locating system in Hebei during 1999- 2010 and lightning disaster data in Hebei during 2002- 2010,temporal-spatial distribution characteristics of ground flash and lightning disaster in Hebei Province were analyzed. Annual,monthly and daily changes of ground flash,lightning current intensity and ground flash density in Hebei were analyzed,and we compared ground flash with lightning disaster distribution.

Contribution to the Study and Analysis of the Lightning Aggression on the Wind Turbine

Generally, lightning damage has mainly been to home appliances and telephones, towers and power transmission and generation equipment mal functions and damage due to strikes on power lines. With the adoption of wind power generation equipment, however, lightning damage is also increasing in this area. Through his dimensional characteristics, the wind power system is more exposed in the nature compared to all others systems. Lightning damage is the single largest cause of unplanned downtime in wind turbines, and that downtime is responsible for the loss of countless megawatts of power generation. The wind turbines are important structures, since they can easily attract the wrath of storms hits heights close, they can also capture the most distant. The rotation of the blades may also trigger lightning and result in considerable increase in the number of strikes to a wind turbine unit. Since wind turbines are tall structures, the lightning currents that are injected by return strokes into the turbines will be affected by reflections at the top, at the bottom, and at the junction of the blades with the static base of the turbine. We present our contribution in this paper to study lightning strokes and their effects on the wind turbines with the aim to enrich the work and to suggest more effective means of protection against lightning.

基于网侧资源协调的自储能柔性互联配电系统日前-日内优化

为优化储能型智能软开关(E-SOP)、传统网侧调控设备的运行策略,提升高渗透率光伏配电网运行水平,提出了基于网侧资源协调的自储能柔性互联配电系统日前-日内优化模型。首先,提出了“源网荷储”下多种网侧资源协调利用的多时间尺度优化控制架构;其次,在日前阶段构建计及有载调压变压器、无功补偿装置、联络开关、E-SOP和柔性负荷的长时间有功-无功联合优化模型,在日内阶段建立多目标滚动优化模型,并采用线性化方法将模型转换为混合整数线性规划模型;然后,基于KL散度构建源荷不确定性模糊集,给出日前两阶段分布鲁棒优化模型转化过程和基于列与约束生成算法的求解方法;最后,算例仿真验证所提方法的有效性。

火箭引雷至架空线路与地面电流对比分析

2018—2019年夏季在广州从化开展了火箭引雷试验,雷击对象分为两种,分别是架空线路和地面。对比了两种引雷情况下各阶段雷电流的电流波形参数的差异,发现引雷至地面情况下初始阶段的最大电流、平均电流、转移电荷、作用积分分别是引雷至架空线路情况下的2.8、2.4、2.0、5.3倍。引雷至地面情况下回击的上升时间几何均值为0.25μs,小于引雷至线路情况下的0.60μs,而对于电流峰值等其他回击波形参数而言,差异不明显。M分量与初始连续电流脉冲类似,引雷至线路情况下的电流峰值、转移电荷、连续电流水平均小于引雷至地面情况下的。基于诺顿电流源等效电路模型分析两种引雷情况下雷电流不同阶段存在差异的原因,可能是雷电在不同电流阶段时其通道等效阻抗不一样所导致的。

火箭触发闪电的回击电流及电场特征分析

2019年夏季在广州开展了火箭引雷试验,成功地触发了14次闪电,总回击(RS)数达74次,平均回击数为5.3次,单次闪电的最大回击数为14次。该文对火箭引雷的回击电流及不同距离电场波形特征进行了分析。回击的间隔时间、峰值电流、10%~90%上升时间、半峰值宽度、1 ms转移电荷和1 ms作用积分的几何平均值分别为38.45 ms、12.38 kA、0.25μs、8.31μs、0.68C和2.12×10^(3)A^(2)·s,回击电流的转移电荷量和作用积分量均与回击峰值电流呈幂函数相关性。回击的先导电场强度峰值和回击电场强度峰值会随距离的增大而减小,而电场的10%~90%上升时间和半峰值宽度会随距离的增大而增大。回击电场强度峰值会随距离的增大而呈现出幂函数减小,且峰值电流与不同距离的先导电场强度峰值和回击电场峰值均呈现一定线性相关,距离越大,其线性拟合关系越好。

基于归闪的湖北省两套闪电定位系统对比分析

为研究湖北省两套闪电定位系统,在归闪的基础上研究分析了2015—2020年湖北地区地闪数据,对闪电频次、时空分布、电流强度月分布、雷电流幅值累积概率等主要参数进行了比对分析,研究结果表明:ADTD-2系统在定位正地闪强度存在局部异常值外,比ADTD-1系统具有更高的探测效率,其中正地闪的探测效率比负地闪提升幅度更高,探测负地闪回击的时间分辨率也比ADTD-1系统高,ADTD-2闪电数据整体优于ADTD-1数据。

电力系统中的雷电暂态感知、监测和应用

雷电是造成电力系统故障的首要原因,实现对雷电暂态电压电流信号的感知、监测和数据应用对于维护系统安全稳定运行具有重要意义。面向日益复杂的新型电力系统结构形态,传感器件在满足雷电宽频测量的基础上,监测装置正朝着微型化、高精度、强互联和易取能方向发展。因此,该文基于雷电暂态感知方法、监测装置关键技术和雷击数据统计应用的研究现状,首先介绍了基于不同原理的电压/电场和电流/磁场传感技术,并分析了各自的优缺点;其次梳理了传感器微型化、时间同步、通信和供能等关键技术的最新进展;随后通过对雷击暂态波形的统计分析,探讨了监测数据在雷击故障识别与定位中的应用;最后对电力系统中雷电暂态感知、监测与应用进行总结并对其发展趋势作出展望。