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1
Jiang, Kaihua, Jinhua Zhu, Xianjun Shao, Shaohua Wang, Te Li, and Zhenguo Wang. "Research on lighting fault identification technology of transmission lines based on non-contact sensing." Journal of Physics: Conference Series 2479, no. 1 (April 1, 2023): 012043. http://dx.doi.org/10.1088/1742-6596/2479/1/012043.
Повний текст джерелаАнотація:
Abstract According to field operation records, lightning stroke accounts for 60% of transmission line failures. Therefore, it is of great significance to strengthen lightning protection of the power system. However, there are several lightning faults, and the corresponding protection methods differ. Consequently, identifying lightning stroke faults will be beneficial to take corresponding lightning protection measures. This paper investigates the mechanism of different lightning strike faults, and simulates them by a 110kV transmission line EMTP-ATP model. Analysis and simulation show that the direction of tower current represents lightning’s polarity; the insulator voltage’s direction differs when shielding failure or back striking occurs. If insulator flashovers, the voltage of the insulator drops down to zero, and as the transient process comes to an end, the voltage of the insulator on the nearby tower decreases to zero as well; after the occurrence of back striking flashover, the direction of insulator voltage on nearby tower alters. Based on those features, insulator voltage and tower current are introduced as a characteristic signal, and their direction and rms of them are formed as recognition parameters for lightning stroke identification. The EMTP-ATP simulations demonstrate that the proposed method is correct and effective, and the recognition rate of different lightning faults is 100% under the abovementioned method.
2
Zou, Yu, Zhenjun Xie, Yinguan Song, Deyin Wang, and Xiang Wang. "Analysis of shielding failure of transmission line based on pilot model." Journal of Physics: Conference Series 2369, no. 1 (November 1, 2022): 012046. http://dx.doi.org/10.1088/1742-6596/2369/1/012046.
Повний текст джерелаАнотація:
Since the main way of power transmission in China is overhead line transmission, some overhead lines are in a harsh outdoor environment. Among them, the bypass attack is more serious. Shielding Failure is a severe form of lightning damage. Based on the situation, this article studies the lightning shielding phenomenon of transmission lines. This article uses the pilot development model to simulate the lightning strike process, analyzes the different target objects of the lightning strike, and elaborates and calculates the lightning shielding trip rate. In addition, by changing the protection angle, the height of the tower, the ground inclination of the area where the line is located, and the number of lines, the impact of these four factors on the lightning shielding trip rate is discussed. According to the influencing factors, measures to strengthen the lightning protection performance of the line are proposed.
3
Chen, Jian, Zhengcai Fu, and Yang Zhao. "Resistance behaviour of carbon fibre-reinforced polymers subjected to lightning strikes: Experimental investigation and application." Advanced Composites Letters 28 (January 1, 2019): 2633366X1989227. http://dx.doi.org/10.1177/2633366x19892272.
Повний текст джерелаАнотація:
It is difficult to monitor lightning damage to carbon fibre-reinforced polymers (CFRPs) online. This work experimentally investigates the changes associated with the electrical resistance of CFRPs subjected to lightning strikes. Two kinds of simulated lightning currents with different amplitudes in the range of 10–80 kA were injected into the CFRP samples. By measuring and comparing the changes in the struck-side (front) surface resistance, the surface resistance of the side opposite to the struck-side (back) and the oblique resistance of each sample before and after the lightning strike, it was observed that inflection points exist in the curve of the resistance change rate. The resistance decreases with increasing peak currents before the inflection point and increases when the peak current goes beyond the inflection point. The change rate of the front surface resistance is more sensitive to the lightning damage than are those of the back surface resistance and the oblique resistance. Different simulated lightning currents have approximately the same action integrals at the inflection points of resistance change rate. The characteristics indicate that resistance change detection could be a possible method for the online monitoring of CFRP lightning damage.
4
Nurunnabi, Abu Sadat Mohammad, Md Mozaharul Islam, Mohammad Tipu Sultan, Kursiya Sanwar, and Ishrak Fatema Tofa. "Death by Lightning: Effective Public Health Strategies Needed." Community Based Medical Journal 11, no. 1 (June 16, 2022): 52–55. http://dx.doi.org/10.3329/cbmj.v11i1.60321.
Повний текст джерелаАнотація:
Lightning is one of the leading causes of weather-related fatalities. A man, approximately 30 years old, was brought to the morgue of Kishoreganj District Hospital, Bangladesh, in July 2021, known to be lightning strike victim. During postmortem examination, various types of skin burns were found in the body, at an entry site on and near the head, and at an inferiorly located exit site. The skin injuries consisted of superficial burns, charring, and singed hair; however, there was no deep burn. „Lichtenberg figures‟ were found. Internal findings at autopsy were nonspecific. Epidemiologically, the total number of global annual lightning fatalities range from 6,000 to 24,000 per year. In recent years, Bangladesh experiences a high rate of lightning deaths. We feel that the number of deaths by lightning should be seen as a call to action. Hence, deaths by lightning should be regarded as a public health problem in the country and necessary measures must be taken. Our case study aims to draw the attention of the physicians and public health department on injuries and deaths due to lightning strike. It is also important for forensic professionals to be familiar with the nature of injuries caused by lightning and lightning strike deaths.
CBMJ 2022 January: vol. 11 no. 01 P: 52-55
5
Sestasombut, Pornchai, and Atthapol Ngaopitakkul. "Evaluation of a Direct Lightning Strike to the 24 kV Distribution Lines in Thailand." Energies 12, no. 16 (August 20, 2019): 3193. http://dx.doi.org/10.3390/en12163193.
Повний текст джерелаАнотація:
This paper evaluates the effect of a lightning strike directly on the 24 kV distribution lines in Thailand, where such strikes are one of the main causes of power outages. The voltage across the insulator, and the arrester energy absorbed due to the lightning, need to be analyzed for different grounding distances of the overhead ground wire, ground resistance, lightning impact positions, and lightning current waveforms. Analysis and simulations are conducted using the Alternative Transients Program/Electromagnetic Transients Program (ATP/EMTP) to find the energy absorbed by the arrester and the voltages across the insulator. The results indicate that when surge arresters are not installed, the voltage across the insulator at the end of the line is approximately 1.4 times that in the middle of the line. In addition, the ground resistance and grounding distance of the overhead ground wire affect the voltage across the insulator if the overhead ground wire is struck. When surge arresters are installed, a shorter grounding distance of the overhead ground wire and a lower ground resistance are not always desirable; this is because they reduce the back-flashover rate and the voltage across the insulator if lightning strikes the overhead ground wire. However, lightning strikes to the phase conductor result in high arrester energy and the possibility that the arrester will fail. Furthermore, the tail time of the lightning waveform is a significant variable when considering the energy absorbed by the arrester, whereas the front time is important for the voltage across the insulator. In case lightning strikes directly on the connected point between the overhead lines and the underground cables, the distribution line system is protected only by the lightning arrester at the connection point. The overvoltage at the connection point is lower than the basic impulse level at 24 kV of 125 kV, but the overvoltage at the end of the cable is still more than 125 kV in case the cable is longer than 400 m. When the distribution line system is protected by the lightning arrester at both the connection point and the end of the cable, it results in overvoltage throughout the cable is lower than the critical flashover of insulation. This method is the best way to reduce the failure rate of underground cables and equipment that are connected to the distribution line system.
6
Wang, Yunlong, Lidong Yan, Yongning Wang, and Guochao Yang. "The Research of real-time identification system of types of lightning failures of UHV transmission lines based on UV detection technique." E3S Web of Conferences 185 (2020): 01048. http://dx.doi.org/10.1051/e3sconf/202018501048.
Повний текст джерелаАнотація:
Egineering running experience shows that with the increase of the operating voltage of the transmission line, the lightning trip rate is increasing. According to theoretical calculation ， UHV transmission lines should be provided with full lightning protection characteristics；however，running experience shows that the lightning withstand level of UHV transmission lines is high，not completely lightning protection; it puts forward higher requirements for lightning protection design of UHV transmission line in China. UHV transmission line is mainly against direct lightning stroke characteristics， one is caused by lightning counterattack trip，the other is the shielding failure of lightning around the line to strike the wound caused by the wire. The lightning fault type identification is based on the micro topography of UHV transmission tower，accumulation of historical data，the development of a more targeted and high voltage transmission line lightning protection scheme is of great significance. In this paper, a real-time identification system based on UV detection technology, which has high accuracy and fast response time, is proposed for lightning fault types of UHV transmission lines, the systems use ultraviolet light to realize online detection of high-voltage transmission line tower nearby lightning, can effective observation tower near lightning discharge, and it has the characteristics of continuous detection, longdistance, no power supply, no contact and no disassembly, it provides an advanced technology for the detection of lightning discharge in UHV transmission line.
7
Rakov, Vladimir A. "Mathematical Modeling of Energy Distribution in Entering a Beam into the Workpiece Material in the Course of Electron Beam Welding." Elektrichestvo 6, no. 6 (2021): 4–11. http://dx.doi.org/10.24160/0013-5380-2021-6-4-11.
Повний текст джерелаАнотація:
Lightning can be defined as a transient, high-current (typically tens of kA) electric discharge in air whose length is measured in km. As for any discharge in air, lightning channel is composed of ionized gas, that is, of plasma, whose peak temperature is typically 30,000 K, about five times higher than the temperature of the surface of the Sun. The global lightning flash rate is some tens to a hundred km per second. Lightning initiates many forest fires, and over 30% of all electric power line failures are lightning related. Each commercial aircraft is struck by lightning on average once a year. A lightning strike to an unprotected object or system can be catastrophic. In the first part [1] of the article, an overview of thunderclouds and their charge structure was given, and different types of lightning were described. The existing hypotheses of lightning initiation in thunderclouds were reviewed. In the second part of the article, current and electromagnetic signatures of lightning are characterized and the techniques to measure lightning electric and magnetic fields are discussed
8
Millen, S. L. J., A. Murphy, G. Catalanotti, and G. Abdelal. "Coupled Thermal-Mechanical Progressive Damage Model with Strain and Heating Rate Effects for Lightning Strike Damage Assessment." Applied Composite Materials 26, no. 5-6 (November 11, 2019): 1437–59. http://dx.doi.org/10.1007/s10443-019-09789-z.
Повний текст джерелаАнотація:
AbstractThis paper proposes a progressive damage model incorporating strain and heating rate effects for the prediction of composite specimen damage resulting from simulated lightning strike test conditions. A mature and robust customised failure model has been developed. The method used a scaling factor approach and non-linear degradation models from published works to modify the material moduli, strength and stiffness properties to reflect the effects of combined strain and thermal loading. Hashin/Puck failure criteria was used prior to progressive damage modelling of the material. Each component of the method was benchmarked against appropriate literature. A three stage modelling framework was demonstrated where an initial plasma model predicts specimen surface loads (electrical, thermal, pressure); a coupled thermal-electric model predicts specimen temperature resulting from the electrical load; and a third, dynamic, coupled temperature-displacement, explicit model predicts the material state due to the thermal load, the resulting thermal-expansion and the lightning plasma applied pressure loading. Unprotected specimen damage results were presented for two SAE lightning test Waveforms (B & A); with the results illustrating how thermal and mechanical damage behaviour varied with waveform duration and peak current.
9
Sun, Jinru, Xuanjiannan Li, Xiangyu Tian, Jingliang Chen, and Xueling Yao. "Dynamic electrical characteristics of carbon fiber-reinforced polymer composite under low intensity lightning current impulse." Advanced Composites Letters 29 (January 1, 2020): 2633366X2094277. http://dx.doi.org/10.1177/2633366x20942775.
Повний текст джерелаАнотація:
The distribution and conduction path of lightning current inside carbon fiber-reinforced polymer (CFRP) composites subjected to lightning strikes are determined by their dynamic conductive characteristics. An experimental platform that generates lightning current impulses with variable parameters was established to obtain the equivalent conductivities of CFRPs with different laminated structures. The experimental results indicated that the through-thickness conductivity (10−3 S/mm) was much lower than the in-plane conductivity (100 S/mm). Then, the dynamic conduction model of CFRPs was analyzed based on the anisotropic nonlinear conductivities of CFRPs under lightning currents of 50–1000 A. The CFRP laminate could be regarded as a series circuit of resistance and inductance. The dynamic conductance of the CFRP laminate first increased and then decreased during the single lightning current strike process, which was closely related to the conductive properties of the interlaminar resin. The inductive properties of the CFRP material were manifested in the test results, which showed that the voltage reached the peak value prior to the current waveform and the equivalent conductivities of the CFRPs increased as the rate of increase decreased and the duration increased. In addition, the equivalent inductance of the carbon fiber network was found to be an important part of the inductive effect of CFRP laminates. This research is helpful for understanding the complicated relationships in the lightning current conducting process and can provide experimental and theoretical support for CFRP coupled electrical–thermal simulation studies of lightning direct effects.
10
Hu, Jianping, Ting Zhu, Jianlin Hu, Zhen Fang, and Ruihe Zhang. "Study on the Lightning Protection Performance for a 110 kV Non-Shield-Wired Overhead Line with Anti-Thunder and Anti-Icing Composite Insulators." Energies 16, no. 2 (January 10, 2023): 815. http://dx.doi.org/10.3390/en16020815.
Повний текст джерелаАнотація:
Due to micro landforms and climate, the 110 kV transmission lines crossing the mountain areas are exposed to severe icing conditions for both their high voltage (HV) conductors and shield wires during the winter. Ice accumulation on the shield wire causes excessive sag, which leads to a reduced clearance between earth and HV wires, and could eventually result in tripping of the line due to phase-to-ground flashover. Due to the lack of effective de-icing techniques for the shield wires, removing them completely from the existing overhead line (OHL) structure becomes a reasonable solution to prevent icing accidents. Nevertheless, the risk of exposure to lightning strikes increased significantly after the shield wires were removed. In order to cope with this, the anti-thunder and anti-icing composite insulator (AACI) is installed on the OHLs. In this article, the 110 kV transmission line without shield wire is considered. The shielding failure after installation of the AACIs is studied using the lightning strike simulation models established in the ATP software. The lightning stroke flashover tests are carried out to examine the shielding failures on various designs for the AACIs. Assuming the tower’s earth resistance is 30 Ω, the LWL of back flashover and direct flashover are 630.88 kA and 261.33 kA, respectively, after the installation of AACIs on an unearthed OHL. Due to the unique mechanism of the AACI, the operational voltage level and the height of the pylon have a neglectable influence on its lightning withstand level (LWL). When the length of the parallel protective gap increases from 450 mm to 550 mm, the lightning trip-out rate decreases from 0.104 times/100 km·a to 0.014 times/100 km·a, and the drop rate reaches 86.5%. Therefore, increasing the gap distance for the AACI to provide additional clearance is proven to be an effective method to reduce the shielding failure rates for non-shield-wired OHLs.
11
Liu, Zhuoran, Weidong Shi, and Bo Zhang. "Numerical Analysis of Transient Performance of Grounding Grid with Lightning Rod Installed on Multi-Grounded Frame." Energies 14, no. 12 (June 9, 2021): 3392. http://dx.doi.org/10.3390/en14123392.
Повний текст джерелаАнотація:
In large substations, many lightning rods are installed on multi-grounded frames. The lightning rods, the frame, the grounding grid and the soil form a whole body, and the lightning current will be discharged from many grounding points. In this paper, based on the partial element equivalent circuit method, a numerical model, in the time domain, is developed to simulate the lightning-caused electromagnetic transients on the frame and the grounding grid. The model is verified by field testing and by comparison with commercial software. The model has several features: (1) it has a simple time domain form; (2) it is stable due to a staggered arrangement of space and time variables and an implicit difference scheme used, and (3) the dimension of the equations is relatively small because the unknown variables are divided into several groups, which are calculated one by one. With this method, the transient characteristics of the grounding grid with lightning rods on the frame are calculated, and the factors affecting the results are analyzed. It can be seen that although the frame causes the ground potential rise in an evenly distributed manner, compared with the situation in which the lightning strikes an independent lightning rod, the ground potential decrease rate near the main grounding point is almost the same because most of the current still enters the soil from the grounding electrode closest to the lightning strike. Therefore, even if there is a frame, the nearby facilities should take the same protective measures as in the case of an independent lightning rod. The ground conductors near the grounding points of the frame should be dense enough to reduce the potential gradient. The equipment should be kept at least 10 m away from the grounding point for lightning.
12
Murdiya, Fri, and Rofi Hariadi. "Analysis of Lightning Performance on 345 kV Transmission Lines Using Python Programming." International Journal of Electrical, Energy and Power System Engineering 3, no. 3 (October 12, 2020): 65–76. http://dx.doi.org/10.31258/ijeepse.3.3.65-76.
Повний текст джерелаАнотація:
One of main causes of interruption of electrical power supply is the lightning strike on overhead power transmission lines. The lightning performance of transmission line can be determined by value of shielding failure flashover rate (SFFOR) and back flashover rate (BFOR). The object of this study is to create a computer application to compute lightning performance on the transmission lines using Python programming. Pythons package tkinter used for program interface window. Application programming is done by using the concept of object-oriented programming (OOP) using Pythons keyword class. Validation shows that the application has applied the method correctly with a percentage error 0 % for SFFOR and 3.14 % for BFOR. The application can do analysis on the factors that affecting SFFOR and BFOR such as the effect of thunder day, tower foot resistance, and number of isolator disk. The results obtained in this study is computer application that can perform lightning performance analysis and analysis of factors that can affect it, such as thunder day, tower foot resistance and the number of isolator disk.
13
Rakov, Vladimir A. "Lightning, the Science. Part 1: Modern View." Elektrichestvo 5, no. 5 (2021): 4–16. http://dx.doi.org/10.24160/0013-5380-2021-5-4-16.
Повний текст джерелаАнотація:
Lightning can be defined as a transient, high-current (typically tens of kA) electric discharge in air whose length is measured in km. As for any discharge in air, lightning channel is composed of ionized gas, that is, of plasma, whose peak temperature is typically 30,000 K, about five times higher than the temperature of the surface of the Sun. Lightning was present on Earth long before human life evolved and it may even have played a crucial role in the evolution of life on our planet. The global lightning flash rate is some tens to a hundred km per second. Each year, some 25 million cloud-to-ground lightning discharges occur in the United States, and this number is expected to increase by about 50% due to global warming over the 21st century. Lightning initiates many forest fires, and over 30% of all electric power line failures are lightning related. Each commercial aircraft is struck by lightning on average once a year. A lightning strike to an unprotected object or system can be catastrophic. In the first part of the article, an overview of thunderclouds and their charge structure is given, basic lightning terminology is introduced, and different types of lightning (including the so-called rocket-triggered lightning) are described. For the most common negative cloud-to-ground lightning, main lightning processes are identified and the existing hypotheses of lightning initiation in thunderclouds are reviewed.
14
Farukh, MA, SU Ahmed, MA Islam, and MA Baten. "Spatial Vulnerability Assessment of Extreme Lightning Events in Bangladesh Using GIS." Journal of Environmental Science and Natural Resources 10, no. 2 (November 29, 2018): 11–18. http://dx.doi.org/10.3329/jesnr.v10i2.39008.
Повний текст джерелаАнотація:
This study explores human death, injury and overall casualties as a result of ongoing extreme lightning events in Bangladesh. Especially the month of May starting from 2010 to mid-2017 were taken under consideration for this study where, a total of 1811 lightning casualties composed of 339 fatalities and 273 injuries are identified. Spatial and geographic aspects of division wise lightning events are evaluated with the help of ArcGIS. The annual average number of fatality is 227 for the whole country whereas, 43 fatalities and 35 injuries over the entire study period was found in May only. The rate of lightning fatality is high in Pirganj of Thakurgaon, Nikli of Kishoreganj, Shibganj of Chapainawabganj, Nawabganj of Dinajpur, Ullapara of Sirajganj, Bagmara of Rajshahi, Bhuapur of Tangail, and Tarail of Kishoreganj. The majority of lightning-related fatalities occurred to males. Maximum people affected by lightning strike during working outside like in field, hoar, road side etc. Farming is the major activity during lightning fatalities. One seventh of death people are affected during stay in indoor like-house, mosque etc. The rural people affected by lightning fatalities accounted 93%. The analysis shows that the highest lightning vulnerable zone is Sunamganj, Sylhet.J. Environ. Sci. & Natural Resources, 10(2): 11-18 2017
15
Liu, Jie, Boyan Jia, Zhimeng Zhang, Zimo Wang, Ping Wang, and Jianghai Geng. "Lightning Failure Risk Assessment of Overhead Transmission Lines Based on Modified Dempster–Shafer Theory." Energies 15, no. 7 (March 30, 2022): 2538. http://dx.doi.org/10.3390/en15072538.
Повний текст джерелаАнотація:
Lightning has a certain degree of potential threat to the safe operation of overhead transmission lines. In order to make targeted lightning protection arrangements and reduce the impact of lightning on overhead transmission lines, it is necessary to conduct lightning risk assessments on overhead transmission lines. This paper proposes a lightning failure risk assessment method for overhead transmission lines based on a modified Dempster–Shafer theory. First, analyze the historical lightning failure data of the line, determine the lightning failure impact factors, and use confidence to express the relationship between the lightning failure and the impact factor; then, use entropy weight theory and gray relational theory to calculate the value of mass function, and modify it on this basis; finally, use Dempster–Shafer theory to determine the trust degree and fit this with the calculated lightning trip rate to produce the risk assessment. This paper analyzes the lightning failure data of overhead transmission lines in some areas of Hebei Province. The results show that, compared with the evaluation method of the Dempster–Shafer theory, the accuracy of the evaluation is improved to a certain extent after correcting the mass function value. It can be seen that this method can integrate and comprehensively consider different data and can provide a reference for preventing damage to transmission lines by lightning strike weather.
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Gorbatov, D. V., V. A. Konyshev, T. O. Lukinykh, O. E. Nanii, A. G. Novikov, V. N. Treshchikov, and R. R. Ubaydullaev. "Effect of anisotropy of a single-mode fibre on lightning-induced rotation of polarisation of a light signal in an optical ground wire." Quantum Electronics 52, no. 1 (January 1, 2022): 87–93. http://dx.doi.org/10.1070/qel17970.
Повний текст джерелаАнотація:
Abstract A numerical model is constructed for calculating lightning-induced rapid changes in the polarisation state of a light signal at the output of a fibre-optic communication line with an optical ground wire. It is shown that taking into account anisotropy of real optical fibres has a noticeable effect on the shape of the polarisation rotation speed time profile. It is found that the maximum rate of change in the polarisation state and its temporal profile depend on the location of the lightning strike in the fibre span, the magnitude of fibre anisotropy and the direction of propagation of a light wave.
17
Iwata, M., T. Nakano, M. Kotari, T. Ohtaka, and Y. Goda. "Calculation of OPGW Strands Melting due to DC Arc Discharge Simulating High-Energy Lightning Strike." PLASMA PHYSICS AND TECHNOLOGY 6, no. 2 (2019): 188–92. http://dx.doi.org/10.14311/ppt.2019.2.188.
Повний текст джерелаАнотація:
Metal strands of OPGWs (composite fiber-optic ground wires) installed in overhead power transmission lines are sometimes melted and broken when struck by high-energy lightning. This paper presents the calculation results regarding OPGW strands melting behavior when struck by DC arcs simulating high-energy lightning. The calculations revealed that the melted volume of the strand was 26% of the strand volume before the arc test, i.e. the rate of the non-melted volume of the strand was 74%. On the other hand, the residual tensile strength of the melted strand was 69% of the other non-melted strands after DC arc test. These results suggest there is a strong correlation between the calculated non-melted volume of the strand and the measured residual tensile strength of the melted strand.
18
Sestasombut, Pornchai, and Atthapol Ngaopitakkul. "Lightning Protection Improvement and Economic Evaluation of Thailand’s 24 kV Distribution Line Based on Difference in Grounding Distance of Overhead Ground Wire." Mathematical Problems in Engineering 2021 (October 4, 2021): 1–14. http://dx.doi.org/10.1155/2021/9969032.
Повний текст джерелаАнотація:
This study determines the voltage across insulators after a direct lightning strike to an overhead ground wire on a 24 kV pole structure for different grounding distances of overhead ground wire, to calculate the maximum ground resistance required to avoid disruption of the distribution line system using ATP-EMTP software. The results show that when a 40 kA lightning current, the average lightning current in Thailand, strikes a 24 kV pole structure, the maximum ground resistance should not exceed 4 Ω for a 40 m grounding distance of overhead ground wire, based on an existing critical insulator flashover of 205 kV. However, because the average ground resistance in Thailand is approximately 10 Ω, this study proposes increasing the insulation level from 205 kV to 300 kV to reduce the likelihood of power outage. The cost-effectiveness of such an investment is assessed in terms of net present value (NPV), internal rate of return (IRR), profitability index (PI), and discounted payback period (DPP) using existing economic tools. Results show that when the critical insulator flashover is increased from 205 kV to 300 kV for a 40 m grounding distance of overhead ground wire, the project is likely to have a DPP of 15.12 years, NPV of 143,321.87 USD, IRR of 12%, and PI of 1.15. On the other hand, grounding distances greater than 40 m for overhead ground wire result in negative NPV, although the back flashover rate can be reduced by 1.51–5.71% with grounding distances of 80–200 m compared to the situation in the absence of grounding.
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Adukauskienė, Dalia, Venta Vizgirdaitė, and Sandra Mažeikienė. "Electrical injuries." Medicina 43, no. 3 (March 6, 2007): 259. http://dx.doi.org/10.3390/medicina43030032.
Повний текст джерелаАнотація:
Electrical trauma can be caused by low-voltage current (from 60 to 1000 V, usually 220 or 360 V), high-voltage (more than 1000 V) current, lightning, and voltaic arc. Often victims are little children, teenagers, and working-age adults. Electrical injuries and clinical manifestations can vary a lot and range from mild complaints undemanding serious medical help to life-threatening conditions. Lightning causes serious injuries in 1000–1500 individuals every year worldwide. The case fatality rate is about 20–30%, with as many as 74% of survivors experiencing permanent injury and sequela. The primary cause of death in victims of lightning strike or other electrical trauma is cardiac or respiratory arrest. That is why appropriate urgent help is essential. Subsequently electrical burns, deep-tissue and organ damage caused by electricity, secondary systemic disorders often demand intensive care and prompt, usually later multistage surgical treatment; therefore, prevention of electrical trauma, which would help to reduce electrical injuries in children and working-age population, is very actual. The most important is to understand the possible danger of electricity and to avoid it.
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Kumar, Udaya, Rosy B. Raysaha, and K. P. Dileep Kumar. "Time Domain Modelling of First Return Stroke of Lightning." Open Atmospheric Science Journal 2, no. 1 (December 29, 2008): 261–70. http://dx.doi.org/10.2174/1874282300802010261.
Повний текст джерелаАнотація:
The four most important factors that govern the return stroke evolution can be identified as: (i) electric field due to charge distributed along the channel, (ii) transient enhancement of conductance by several orders at the bridging regime (iii) the non-linear increase in channel conductance at the propagating current front and (iv) the associated dynamic electromagnetic field which support the evolution of current along the channel. For a more realistic modelling of the lightning return stroke, the present work attempts to consider these aspects in suitable manner. The charge simulation method is employed for evaluating the quasi-static field due to (i). For the dynamic field, the problem involves conduction along a thin structure with open boundary on one side. Further, in order to efficiently represent a vertically extended grounded strike object, as well as, channel of quite arbitrary geometry, boundary based approach is believed to be the ideal choice. Considering these, a time-dependent electric field integral equation (TD-EFIE) along with a sub-sectional collocation form of the method of moments (MoM) is chosen for the numerical field evaluation. The dynamic variation of conductance in the channel other than the bridging zone is modelled by a first order arc equation. For the bridging zone, arc equation which explicitly portray in some sense, accumulation of energy is considered. Accordingly, formulations given by Barannik, Popovic and Toepler were scrutinized for their suitability. After some preliminary simulation studies, a self contained model for the first return stoke of a lightning flash is presented. The stability of the model is verified by running the program for longer durations with different cloud base potentials and cloud base heights. Simulation results are in agreement with the field data on current and velocity decay rate for the first one kilometer height. Also, the relation between the charge density at channel tip and the return stroke current peak favorably compares with the literature.
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Wiens, Kyle C., Steven A. Rutledge, and Sarah A. Tessendorf. "The 29 June 2000 Supercell Observed during STEPS. Part II: Lightning and Charge Structure." Journal of the Atmospheric Sciences 62, no. 12 (December 1, 2005): 4151–77. http://dx.doi.org/10.1175/jas3615.1.
Повний текст джерелаАнотація:
Abstract This second part of a two-part study examines the lightning and charge structure evolution of the 29 June 2000 tornadic supercell observed during the Severe Thunderstorm Electrification and Precipitation Study (STEPS). Data from the National Lightning Detection Network and the New Mexico Tech Lightning Mapping Array (LMA) are used to quantify the total and cloud-to-ground (CG) flash rates. Additionally, the LMA data are used to infer gross charge structure and to determine the origin locations and charge regions involved in the CG flashes. The total flash rate reached nearly 300 min−1 and was well correlated with radar-inferred updraft and graupel echo volumes. Intracloud flashes accounted for 95%–100% of the total lightning activity during any given minute. Nearly 90% of the CG flashes delivered a positive charge to ground (+CGs). The charge structure during the first 20 min of this storm consisted of a midlevel negative charge overlying lower positive charge with no evidence of an upper positive charge. The charge structure in the later (severe) phase was more complex but maintained what could be roughly described as an inverted tripole, dominated by a deep midlevel (5–9 km MSL) region of positive charge. The storm produced only two CG flashes (both positive) in the first 2 h of lightning activity, both of which occurred during a brief surge in updraft and hail production. Frequent +CG flashes began nearly coincident with dramatic increases in storm updraft, hail production, total flash rate, and the formation of an F1 tornado. The +CG flashes tended to cluster in or just downwind of the heaviest precipitation, which usually contained hail. The +CG flashes all originated between 5 and 9 km MSL, centered at 6.8 km (−10°C), and tapped LMA-inferred positive charge both in the precipitation core and (more often) in weaker reflectivity extending downwind. All but one of the −CG flashes originated from >9 km MSL and tended to strike near the precipitation core.
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Millen, S. L. J., S. Ashworth, C. Farrell, and A. Murphy. "Understanding and representing heating and heating rate effects on composite material properties for lightning strike direct effect simulations." Composites Part B: Engineering 228 (January 2022): 109438. http://dx.doi.org/10.1016/j.compositesb.2021.109438.
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Yamaguchi, Nobuhiro, Kazuyuki Ishimoto, Ryota Mori, and Jyoji Kawano. "Influence of Medium Voltage Distribution Line Configuration on Phase to Phase Sparkover Rate due to Direct Lightning Strike." IEEJ Transactions on Power and Energy 142, no. 2 (February 1, 2022): 114–20. http://dx.doi.org/10.1541/ieejpes.142.114.
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Millen, S. L. J., A. Murphy, G. Catalanotti, and G. Abdelal. "Correction to: Coupled Thermal–Mechanical Progressive Damage Model with Strain and Heating Rate Effects for Lightning Strike Damage Assessment." Applied Composite Materials 27, no. 6 (November 9, 2020): 989. http://dx.doi.org/10.1007/s10443-020-09841-3.
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Yamaguchi, Nobuhiro, Joji Kawano, and Kazuyuki Ishimoto. "Influence of Salt Pollution of Insulators on Sparkover Rate of Medium Voltage Distribution Lines due to Direct Lightning Strike." IEEJ Transactions on Power and Energy 143, no. 3 (March 1, 2023): 207–13. http://dx.doi.org/10.1541/ieejpes.143.207.
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Ramachandran, V., J. N. Prakash, A. Deo, and S. Kumar. "Lightning stroke distance estimation from single station observation and validation with WWLLN data." Annales Geophysicae 25, no. 7 (July 30, 2007): 1509–17. http://dx.doi.org/10.5194/angeo-25-1509-2007.
Повний текст джерелаАнотація:
Abstract. A simple technique to estimate the distance of the lightning strikes d with a single VLF electromagnetic wave receiver at a single station is described. The technique is based on the recording of oscillatory waveforms of the electric fields of sferics. Even though the process of estimating d using the waveform is a rather classical one, a novel and simple procedure for finding d is proposed in this paper. The procedure adopted provides two independent estimates of the distance of the stroke. The accuracy of measurements has been improved by employing high speed (333 ns sampling rate) signal processing techniques. GPS time is used as the reference time, which enables us to compare the calculated distances of the lightning strikes, by both methods, with those calculated from the data obtained by the World-Wide Lightning Location Network (WWLLN), which uses a multi-station technique. The estimated distances of the lightning strikes (77), whose times correlated, ranged from ~3000–16 250 km. When d<3500 km, the average deviation in d compared with those calculated with the multi-station lightning location system is ~4.7%, while for all the strokes it was ~8.8%. One of the lightnings which was recorded by WWLLN, whose field pattern was recorded and the spectrogram of the sferic was also recorded at the site, is analyzed in detail. The deviations in d calculated from the field pattern and from the arrival time of the sferic were 3.2% and 1.5%, respectively, compared to d calculated from the WWLLN location. FFT analysis of the waveform showed that only a narrow band of frequencies is received at the site, which is confirmed by the intensity of the corresponding sferic in the spectrogram.
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Lehman, L. B. "Successful Management of an Adult Lightning Victim Using Intracranial Pressure Monitoring." Neurosurgery 28, no. 6 (June 1, 1991): 907–10. http://dx.doi.org/10.1227/00006123-199106000-00024.
Повний текст джерелаАнотація:
Abstract Serious central nervous system injuries after lightning strikes are fortunately rare. Optimal neurological and neurosurgical management has not been firmly established. We describe the successful neurological resuscitation and critical care management using intracranial pressure monitoring of an adult who sustained a lightning strike. The role of intracranial pressure monitoring in this setting is discussed.
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Shipman, Jeffrey, Brittany Carver, Kelly Painter, and Stacia Shipman. "The Dangerous Life of a Storm Chaser: A Lightning Strike Injury Causing Serious Injury." Journal of Investigative Medicine High Impact Case Reports 8 (January 2020): 232470962092556. http://dx.doi.org/10.1177/2324709620925566.
Повний текст джерелаАнотація:
Lightning strikes to people are rare events that cause significant injuries and mortality when they do occur. We describe an uncommon case of a storm chaser in Oklahoma who was struck by lightning who suffered cutaneous burns, bilateral tympanic membrane ruptures, as well as pulmonary edema, which is an atypical finding in survivors. This case report highlights several injury patterns seen in lightning strike cases and provides evidence that these patients should be managed at a center with multidisciplinary services available.
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Bhargava, Amita N., Gaurav M. Kasundra, Subhakaran Khichar, and Bharat S. K. Bhushan. "Lightning strike-induced brachial plexopathy." Journal of Neurosciences in Rural Practice 05, no. 04 (October 2014): 399–400. http://dx.doi.org/10.4103/0976-3147.140000.
Повний текст джерелаАнотація:
ABSTRACTWe describe a patient who presented with a history of lightning strike injury. Following the injury, he sustained acute right upper limb weakness with pain. Clinically, the lesion was located to the upper and middle trunk of the right brachial plexus, and the same confirmed with electrophysiological studies. Nerve damage due to lightning injuries is considered very rare, and a plexus damage has been described infrequently, if ever. Thus, the proposed hypothesis that lightning rarely causes neuropathy, as against high-voltage electric current, due to its shorter duration of exposure not causing severe burns which lead to nerve damage, needs to be reconsidered.
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Veina, V. Harsha, S. P. Ramanathan, S. Kokilavani, S. G. Patil, S. D. Pawar, V. Gopalakrishnan, Somnath Mahapatra, and P. Balasubramaniam. "Spatial Vulnerability Assessment and Diurnal Climatology of Lightning Events in Tamil Nadu, India." International Journal of Environment and Climate Change 13, no. 9 (July 6, 2023): 490–501. http://dx.doi.org/10.9734/ijecc/2023/v13i92261.
Повний текст джерелаАнотація:
The research probes into the seven agro climatic zones in Tamil Nadu which are highly vulnerable to lightning strikes, as well as the human fatalities caused by Cloud to Ground lightning. The purpose of the study is to find out the vulnerable hotspots and diurnal climatology of the Cloud to Ground lightning strikes during the northeast monsoon, southwest monsoon, and summer seasons. Heat maps are used for the lightning strikes using ArcGIS software and the diurnal climatology was performed by interpolating the data from the lightning location network into a 3-hour resolution. In vulnerability analysis, Northeastern zone is more prone to lightning during Southwest and Northeast Monsoon. On the other hand, High rainfall zone and Hilly zone are vulnerable to lightning in summer season. The Northeast monsoon has the highest lightning frequency ratio, followed by the summer. The maximum rate of strikes occurred between 10-15 hrs IST and showed a peak range between 10:00 to 12:00 hrs IST. A labor-intensive agricultural economy is linked to higher rates of lightning-related deaths and injuries. The results of this research could be useful in developing lightning climatology for the future climatic condition for Tamil Nadu.
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Styger, Jenny, Jon Marsden-Smedley, and Jamie Kirkpatrick. "Changes in Lightning Fire Incidence in the Tasmanian Wilderness World Heritage Area, 1980–2016." Fire 1, no. 3 (October 19, 2018): 38. http://dx.doi.org/10.3390/fire1030038.
Повний текст джерелаАнотація:
The Tasmanian Wilderness World Heritage Area (TWWHA) has globally significant natural and cultural values, some of which are dependent on the absence of fire or the presence of particular fire regimes. Planned burning is currently used to reduce the risk of loss of world heritage values from unplanned fires, but large and damaging fires still occur, with lightning as the primary ignition source. Lightning-caused fire was rare in the TWWHA before 2000. There has since been an increase in both the number of fires following lightning storms and the area burnt by these fires. In the absence of a direct measurement of lightning strike incidence, we tested whether changes in rainfall, soil dryness and fuel load were responsible for these changes in fire incidence and extent. There were no relationships between these variables and the incidence of fires associated with lightning, but the variability in the Soil Dryness Index and the mean of 25% of driest values did predict both the number and area of fires. Thus, it appears that an increase in the proportion of lightning strikes that occur in dry conditions has increased ignition efficiency. These changes have important implications for the management of the TWWHA’s values, as higher projected fuel loads and drier climates could result in a further increase in the number of fires associated with lightning.
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Fan, Xiangpeng, Yijun Zhang, Guangshu Zhang, and Dong Zheng. "Lightning Characteristics and Electric Charge Structure of a Hail-Producing Thunderstorm on the Eastern Qinghai–Tibetan Plateau." Atmosphere 9, no. 8 (July 29, 2018): 295. http://dx.doi.org/10.3390/atmos9080295.
Повний текст джерелаАнотація:
An isolated hail-producing thunderstorm that occurred on 20 August 2012, from the Composite Observing Experiment for Lightning project carried out in the Da Tong Region of Qinghai Province, China, was studied. In most stages, the charge structure in the storm showed a positive tripole structure, which resulted in a low positive ground lightning rate for the whole event. In the thunderstorm process, 202 lightning flashes were detected. The peak lightning rate of lightning was 28 times/5 min. The average number of return strokes of negative ground flash was 2.4, and only one return stroke of positive ground lightning occurred. The duration of the in-cloud process prior to the first return stroke was relatively long. Dynamic transport had a considerable influence on the charge structure of the cloud. Before and after hail landing, the ground electric field of several stations showed a consistent trend of reversal.
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Wang, Guoming, Woo-Hyun Kim, Gyung-Suk Kil, Dae-Won Park, and Sung-Wook Kim. "An Intelligent Lightning Warning System Based on Electromagnetic Field and Neural Network." Energies 12, no. 7 (April 2, 2019): 1275. http://dx.doi.org/10.3390/en12071275.
Повний текст джерелаАнотація:
Prediction of lightning occurrence has significant relevance for reducing potential damage to electric installations, buildings, and humans. However, the existing lightning warning system (LWS) operates using the threshold method and has low prediction accuracy. In this paper, an intelligent LWS based on an electromagnetic field and the artificial neural network was developed for improving lightning prediction accuracy. An electric field mill sensor and a pair of loop antennas were designed to detect the real-time electric field and the magnetic field induced by lightning, respectively. The change rate of electric field, temperature, and humidity acquired 2 min before lightning strikes, were used for developing the neural network using the back propagation algorithm. After observing and predicting lightning strikes over six months, it was verified that the proposed LWS had a prediction accuracy of 93.9%.
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Turan, Mahfuz, Ferhat Kalkan, Nazım Bozan, İsa Özçalimli, Mehmet Zeki Erdem, Abdülaziz Yalınkılıç, and Mehmet Fatih Garca. "Isolated Sensorineural Hearing Loss as a Sequela after Lightning Strike." Case Reports in Otolaryngology 2015 (2015): 1–4. http://dx.doi.org/10.1155/2015/738416.
Повний текст джерелаАнотація:
In most of the surviving patients after a lightning strike, audiovestibular abnormalities have been reported. The most frequently reported type of abnormalities is a tympanic membrane perforation with hearing loss and external ear canal burn. However a sensor neural hearing loss and mixed type hearing loss can also occur, but these occur rarely. A nineteen-year-old female patient had, after a lightning strike, serious burns on the left ear, behind the ear, and on the chest and neck. She also had in her left ear 108 dB hearing loss with irregular central perforation and in her right ear 52 dB sensorineural hearing loss. There was no hearing loss before the strike. A hearing aid was recommended for the right ear and good care and follow-up were recommended for the left ear. A lightning strike can cause serious audiological damage. Therefore, it is necessary to make a careful audiovestibular evaluation of the patients. Although there exist rarely healed cases from sensorineural hearing loss after lightning strike in literature, in our case hearing loss occurred bilaterally and then it healed unilaterally. This condition is quite rare in literature.
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Masłowski, Grzegorz. "Corona current concept in lightning return-stroke models of engineering type." Archives of Electrical Engineering 59, no. 3-4 (December 1, 2010): 177–88. http://dx.doi.org/10.2478/s10171-010-0014-z.
Повний текст джерелаАнотація:
Corona current concept in lightning return-stroke models of engineering typeA role of radial corona current in a lightning discharge is discussed in the paper. It is shown that the corona current concept previously introduced by Cooray for lightning return stroke models of distributed-current-source (DCS) type, and later, by Maslowski and Rakov for lumped-current-source (LCS) type models enables to show duality between these two types of models. Further, it is demonstrated that the corona current is useful during consideration of dynamics of the lightning-channel corona sheath. As an example of application of presented approach a relaxation model of charge motion in the corona sheath is analysed together with plots which show the rate of expansion and shrinkage of the lightning corona sheath on both microsecond and millisecond time scales.
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Zalhaf, Amr S., Bahaa Elboshy, Kotb M. Kotb, Yang Han, Abdulrazak H. Almaliki, Reda M. H. Aly, and M. R. Elkadeem. "A High-Resolution Wind Farms Suitability Mapping Using GIS and Fuzzy AHP Approach: A National-Level Case Study in Sudan." Sustainability 14, no. 1 (December 29, 2021): 358. http://dx.doi.org/10.3390/su14010358.
Повний текст джерелаАнотація:
Wind energy is one of the most attractive sustainable energy resources since it has low operation, maintenance, and production costs and a relatively low impact on the environment. Identifying the optimal sites for installing wind power plants (WPPs) is considered an important challenge of wind energy development which requires careful and combined analyses of numerous criteria. This study introduces a high-resolution wind farms suitability mapping based on Fuzzy Analytical Hierarchy Process (FAHP) and Geographic Information System (GIS) approaches considering technical, environmental, social, and spatial aspects, representing eight different criteria. First, a multi-criteria decision-making analysis based on the FAHP method is employed to assign appropriate weights for the addressed criteria with respect to their relative importance. Since the traditional AHP method, which was found employed in the majority of the relative case-studies, is not efficient in dealing with uncertainty when experts use a basic scale (0 to 1) for their assessments, the FAHP provides more flexible scales through the utilized fuzzy membership functions and the natural linguistic variables. Consequently, this helps to facilitate the assessments made by experts and increases the precision of the obtained results (weights). Next, the high-resolution GIS is used to carry out a spatial analysis and integrate various factors/criteria throughout the proposed index to produce the final suitability map and identify the unsuitable areas. The presented study emphasizes investigating the lightning strike flash rate due to its significant influences on the wind turbine’s safety and operation, yet this crucial factor has been seldomly investigated in previous studies. The obtained findings revealed that the wind speed, the land slope, and the elevation had the highest weighted criteria with 33.1%, 24.8%, and 12.2%, respectively. Besides, the final-developed suitability map revealed that 23.22% and 8.31% of the Sudanese territory are of high and very high suitability, respectively, for wind farms installation which are considered sufficient to cover the electricity needs. The difficulty of acquiring real data and resources for the addressed location was the main challenge of the presented work. The work outlook addresses the suitability mapping of hybrid photovoltaic-wind turbine energy systems, which will require addressing new and significant criteria in the applied methodology.
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Huntrieser, H., U. Schumann, H. Schlager, H. Höller, A. Giez, H. D. Betz, D. Brunner, C. Forster, and R. Calheiros. "Lightning activity in Brazilian thunderstorms during TROCCINOX: implications for NO<sub>x</sub> production." Atmospheric Chemistry and Physics Discussions 7, no. 5 (October 16, 2007): 14813–94. http://dx.doi.org/10.5194/acpd-7-14813-2007.
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Abstract. During the TROCCINOX field experiment in January and February 2005, the contribution of lightning-induced nitrogen oxides (LNOx) from tropical and subtropical thunderstorms in Southern Brazil was investigated. Airborne trace gas measurements (NO, NOy, CO and O3) were performed up to 12.5 km with the German research aircraft Falcon. During anvil penetrations in selected tropical and subtropical thunderstorms of 4 and 18 February, NOx mixing ratios were on average enhanced by 0.7–1.2 and 0.2–0.8 nmol mol−1 totally, respectively. The relative contributions of boundary layer NOx (BL-NOx) and LNOx to anvil-NOx were derived from the NOx-CO correlations. On average ~80–90% of the anvil-NOx was attributed to LNOx. A Lightning Location Network (LINET) was set up to monitor the local distribution of cloud-to-ground (CG) and intra-cloud (IC) radiation sources (here called "strokes") and compared with lightning data from the operational Brazilian network RINDAT (Rede Integrada Nacional de Detecção de Descargas Atmosféricas). The horizontal LNOx mass flux out of the anvil was determined from the mean LNOx mixing ratio, the horizontal outflow velocity and the size of the vertical cross-section of the anvil, and related to the number of strokes contributing to LNOx. The values of these parameters were derived from the airborne measurements, from lightning and radar observations, and from a trajectory analysis. The amount of LNOx produced per LINET stroke depending on measured peak current was determined. The results were scaled up with the Lightning Imaging Sensor (LIS) flash rate (44 flashes s−1) to obtain an estimate of the global LNOx production rate. The final results gave ~1 and ~2–3 kg(N) per LIS flash based on measurements in three tropical and one subtropical Brazilian thunderstorms, respectively, suggesting that tropical flashes may be less productive than subtropical ones. The equivalent mean annual global LNOx nitrogen mass production rate was estimated to be 1.6 and 3.1 Tg a−1, respectively. By use of LINET observations in Germany in July 2005, a comparison with the lightning activity in mid-latitude thunderstorms was also performed. In general, the same frequency distribution of stroke peak currents as for tropical thunderstorms over Brazil was found. The different LNOx production rates per stroke in tropical thunderstorms compared with subtropical and mid-latitude thunderstorms seem to be related to the different stroke lengths (inferred from comparison with laboratory data and observed lengths). In comparison, the impact of other lightning parameters as stroke peak current and stroke release height was assessed to be minor. The results from TROCCINOX suggest that the different vertical wind shear may be responsible for the different stroke lengths.
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Huntrieser, H., U. Schumann, H. Schlager, H. Höller, A. Giez, H. D. Betz, D. Brunner, C. Forster, O. Pinto, and R. Calheiros. "Lightning activity in Brazilian thunderstorms during TROCCINOX: implications for NO<sub>x</sub> production." Atmospheric Chemistry and Physics 8, no. 4 (February 25, 2008): 921–53. http://dx.doi.org/10.5194/acp-8-921-2008.
Повний текст джерелаАнотація:
Abstract. During the TROCCINOX field experiment in January and February 2005, the contribution of lightning-induced nitrogen oxides (LNOx) from tropical and subtropical thunderstorms in Southern Brazil was investigated. Airborne trace gas measurements (NO, NOy, CO and O3) were performed up to 12.5 km with the German research aircraft Falcon. During anvil penetrations in selected tropical and subtropical thunderstorms of 4 and 18 February, NOx mixing ratios were on average enhanced by 0.7–1.2 and 0.2–0.8 nmol mol−1 totally, respectively. The relative contributions of boundary layer NOx (BL-NOx) and LNOx to anvil-NOx were derived from the NOx-CO correlations. On average ~80–90% of the anvil-NOx was attributed to LNOx. A Lightning Location Network (LINET) was set up to monitor the local distribution of cloud-to-ground (CG) and intra-cloud (IC) radiation sources (here called "strokes") and compared with lightning data from the operational Brazilian network RINDAT (Rede Integrada Nacional de Detecção de Descargas Atmosféricas). The horizontal LNOx mass flux out of the anvil was determined from the mean LNOx mixing ratio, the horizontal outflow velocity and the size of the vertical cross-section of the anvil, and related to the number of strokes contributing to LNOx. The values of these parameters were derived from the airborne measurements, from lightning and radar observations, and from a trajectory analysis. The amount of LNOx produced per LINET stroke depending on measured peak current was determined. The results were scaled up with the Lightning Imaging Sensor (LIS) flash rate (44 flashes s−1) to obtain an estimate of the global LNOx production rate. The final results gave ~1 and ~2–3 kg(N) per LIS flash based on measurements in three tropical and one subtropical Brazilian thunderstorms, respectively, suggesting that tropical flashes may be less productive than subtropical ones. The equivalent mean annual global LNOx nitrogen mass production rate was estimated to be 1.6 and 3.1 Tg a−1, respectively. By use of LINET observations in Germany in July 2005, a comparison with the lightning activity in mid-latitude thunderstorms was also performed. In general, the same frequency distribution of stroke peak currents as for tropical thunderstorms over Brazil was found. The different LNOx production rates per stroke in tropical thunderstorms compared with subtropical and mid-latitude thunderstorms seem to be related to the different stroke lengths (inferred from comparison with laboratory data and observed lengths). In comparison, the impact of other lightning parameters as stroke peak current and stroke release height was assessed to be minor. The results from TROCCINOX suggest that the different vertical wind shear may be responsible for the different stroke lengths.
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Sharma, Shriram, Prabidhi Shrestha, and Pitambar Shrestha. "Telecom towers under the threat of lightning hazards." Scientific World 15, no. 15 (June 14, 2022): 158–66. http://dx.doi.org/10.3126/sw.v15i15.45666.
Повний текст джерелаАнотація:
Lightning is an extremely complex electrical discharge that occurs within the earth’s atmosphere. It is the biggest threat to communication and transmission towers and damages electronic and electrical equipment beyond repair directly or indirectly. Although the protection against the lightning hazards can be achieved with the available technology and knowledge, such measures are largely overlooked in the developing countries in particular. Protecting communication & transmission towers, communication & transmission systems from the direct lightning strikes and saving human lives, livestock and other property damages from indirect lightning is a big challenge to the service providers. Nepal is a lightning prone country where the communication towers and system are often the victims of lightning strikes. In this study, we have made field assessment at the various sites of Nepal Telecom’s Base Transceiver Station (BTS) and Repeater towers for investigating their status pertinent to lightning threat and protective measures adopted in those sites. The main objectives of the field assessment were to investigate the effectiveness of the protective measures adopted, identify their inadequacies and hence to provide appropriate solutions as per the international standards (IEC 62305-4), in order to improve the quality of telecom services. The lightning strikes to the towers inside the Kathmandu valley were recorded to be rare, however it was common in the outskirts. Although, severe damage to the towers were not observed neither were recorded, the status of the towers in the perspective of lightning hazards were not found to be in the sound state. Contact resistance of the earthing system, installation of SPDs and equipotential bonding of the system need to be improved. Further, the protective measures against the hazards due to indirect effects of lightning strikes were found to be extremely poor. We recommend the improvements in protective measures against lightning in the neighborhood of the towers for the human as well as equipment safety.
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Kountouris, Alex, John W. Orchard, Rajesh Puranik, Christopher Semsarian, Jessica J. Orchard, David Samra, Johan Duflou, Patrick Groenestein, Mark Young, and Peter Brukner. "Prevention of Sudden Cardiac Death in Cricketers." Journal of Postgraduate Medicine, Education and Research 50, no. 2 (2016): 49–58. http://dx.doi.org/10.5005/jp-journals-10028-1193.
Повний текст джерелаАнотація:
ABSTRACT Aims Sudden death in cricketers is rare, with the most common causes being cardiac, neurological (head/neck trauma, mainly from ball impact) and environmental (e.g., lightning strike and heat stroke, the former which usually involves cardiac arrest). The aim of this study was to review possible prevention of sudden cardiac death and make recommendations. Materials and methods A literature review of possible causes of sudden cardiac death (SCD) among cricketers was performed, along with evaluation of evidence for existing preventative measures. The method for evaluation was expert panel (cardiology and sports medicine) consensus recommendations based on the published evidence base. Results Potential cardiac causes of sudden death while playing cricket can be divided into the following categories: (1) atraumatic-origin preexisting arrhythmias, cardiomyopathies and valve disorders (2) traumatic-origin arrhythmia (commotio cordis) (3) acquired coronary or valvular disease (4) viral myocarditis (5) Lightning strike. Preventive measures can be divided into pre-season (e.g., cardiovascular screening), prematch (e.g., assessment of viral illness), protective equipment (e.g., chest guards) and post-event (presence of first aid response including defibrillators). Our panel agreed that there was strong evidence that (1) trained and planned emergency response particularly with a defibrillator is effective at preventing SCD and (2) ceasing play in the presence of lightning strikes prevents lightning-related death (3) players with symptoms, risk factors or history suggestive of possible cardiac disease should undertake specific individual workup. There are other potential methods to prevent SCD, with expert level recommendations made in the absence of strong evidence. Discussion and conclusion The most controversial aspect of prevention of SCD is electrocardiogram (ECG) screening of asymptomatic players and this paper outlines the arguments both in favor and against without fully resolving the debate. The possible increase in early diagnosis of potentially life-threatening cases needs to be balanced against the risk of false positive results which may lead to discussion of exclusion from cricket. Cardiac workup is clearly of net benefit to symptomatic individuals (e.g. history of syncope, chest pain) or any player at higher than usual baseline risk (e.g., positive family history). Basic life support including access to defibrillators should be available with trained personnel wherever they can be afforded, which has strong evidence in favor of improving survival at the time of cardiac arrest. How to cite this article Orchard JW, Puranik R, Semsarian C, Orchard JJ, Samra D, Duflou J, Groenestein P, Young M, Brukner P, Kountouris A. Prevention of Sudden Cardiac Death in Cricketers. J Postgrad Med Edu Res 2016;50(2):49-58.
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Hall, Beth L. "Precipitation associated with lightning-ignited wildfires in Arizona and New Mexico." International Journal of Wildland Fire 16, no. 2 (2007): 242. http://dx.doi.org/10.1071/wf06075.
Повний текст джерелаАнотація:
From 1990 to 1998, over 17000 naturally ignited wildfires were observed in Arizona and New Mexico on US federal land during the fire season of April through October. Lightning strikes associated with these fires accounted for less than 0.35% of all recorded cloud-to-ground lightning strikes that occurred during the fire season during that time. Given the high aridity of this region, why do some lightning strikes ignite fires and others not? Natural wildfire ignitions in this region are often attributed to what is referred to as ‘dry’ lightning, or lightning with little or no precipitation. This study used daily and hourly gridded precipitation derived from historical gauge data to compare the amount of precipitation associated with natural wildfires and the amount of precipitation associated with lightning strikes that were not associated with natural wildfire events. Climatology of natural ignitions tend to peak before the time of the seasonal maximum lightning flashes and precipitation, suggesting ‘dry’ ignitions in the early part (e.g. late June, early July) of the wildfire season. Observed natural wildfires were more often associated with conditions of <2 mm of precipitation on the day of the event than were cases without an associated ignition. The majority of lightning flashes that did not cause a discovered wildfire were associated with a higher precipitation rate after the timing of the event, which suggests the possibility of the precipitation extinguishing the wildfires before discovery. Most lightning flashes that were not associated with a discovered ignition had twice as many hours with some measurable precipitation than where there were discovered ignitions, which eludes to the longer-term impact of preceding precipitation on the fuels than the lightning storm-associated precipitation. These results can be applied to gridded forecasts of amount of precipitation to indicate areas where there is an increased probability of natural wildfire ignition, assuming the other factors of ignition source and fuel availability are present.
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de Abreu, Lizandro Pereira, Weber Andrade Gonçalves, Enrique Vieira Mattos, Pedro Rodrigues Mutti, Daniele Torres Rodrigues, and Marcos Paulo Araújo da Silva. "Clouds’ Microphysical Properties and Their Relationship with Lightning Activity in Northeast Brazil." Remote Sensing 13, no. 21 (November 8, 2021): 4491. http://dx.doi.org/10.3390/rs13214491.
Повний текст джерелаАнотація:
The Northeast region of Brazil (NEB) has a high rate of deaths from lightning strikes (18% of the country’s total). The region has states, such as Piauí, with high mortality rates (1.8 deaths per million), much higher than the national rate (0.8) and the NEB rate (0.5). In this sense, the present work analyzes the microphysical characteristics of clouds with and without the occurrence of total lightning. For this purpose, data from the Lightning Imaging Sensor (LIS), TRMM Microwave Imager (TMI) and Precipitation Radar (PR), aboard the Tropical Rainfall Measuring Mission (TRMM) satellite from 1998 to 2013 were used. The TRMM data were analyzed to establish a relationship between the occurrence of lightning and the clouds’ microphysical characteristics, comparing them as a function of lightning occurrence classes, spatial location and atmospheric profiles. A higher lightning occurrence is associated with higher values of ice water path (>38.9 kg m−2), rain water path (>2 kg m−2), convective precipitation (>5 mm h−1) and surface precipitation (>7 mm h−1), in addition to slightly higher freezing level height values. Reflectivity observations (>36 dBZ) demonstrated typical convective profile curves, with higher values associated with classes with higher lightning densities (class with more than 6.8 flash km−2 year−1).
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Gatta, Fabio Massimo, Alberto Geri, Stefano Lauria, Marco Maccioni, and Francesco Palone. "Lightning Performance Evaluation of Italian 150 kV Sub-Transmission Lines." Energies 13, no. 9 (April 30, 2020): 2142. http://dx.doi.org/10.3390/en13092142.
Повний текст джерелаАнотація:
A significant majority of overhead transmission lines’ (OHLs) outages is due to backflashovers caused by direct lightning strikes: the realistic assessment of the lightning performance is thus an important task. The paper presents the analysis of the lightning performance of an existing 150 kV Italian OHL, namely, its backflashover rate (BFOR), carried out by means of an ATP-EMTP-based Monte Carlo procedure. Among other features, the procedure makes use of a simplified pi-circuit for line towers’ grounding system, allowing a very accurate reproduction of transient behaviours at a very low computational cost. Tower grounding design modifications, aimed at improving the OHL lightning performance, are also proposed and discussed.
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Hoole, P. R. P., S. Thirukumaran, Harikrishnan Ramiah, Jeevan Kanesan, and S. R. H. Hoole. "Ground to Cloud Lightning Flash Currents and Electric Fields: Interaction with Aircraft and Production of Ionosphere Sprites." Journal of Computational Engineering 2014 (August 3, 2014): 1–5. http://dx.doi.org/10.1155/2014/869452.
Повний текст джерелаАнотація:
This paper presents for the first time a case for the importance of ground to cloud (upward leader) lightning flash parameters for safety testing of direct aircraft-lightning interaction and protection of wind turbines, as well as the importance of radiated electric fields for indirect lightning-aircraft interaction and generation of electric discharges called sprites and halos in the ionosphere. By using an electric circuit model of the transverse magnetic waves along the return stroke channel, electric currents at ground level as well as cloud level are determined for both the cloud to ground lightning flash and the ground to cloud lightning flash. We show that when an aircraft triggers lightning, the electric currents will be much more severe in current magnitude, rate of rise of currents, and frequency spectrum than otherwise and are more severe than the parameters observed for the usual and well monitored (and measured) cloud to ground (downward leader) flashes. The rate of rise of currents and the frequency spectrum of the ground to cloud lightning flash are also given here. The electric fields radiated by the lightning flashes that would appear in the ionosphere are presented for both the earth flash and the ground to cloud flash.
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Gomba, Rodolphe, and Alphonse Omboua. "Calculation of lightning surges on the high voltage lines. Case of 220 kV line: Ngo -Brazzaville in Congo." International Journal of Engineering & Technology 6, no. 1 (January 23, 2017): 13. http://dx.doi.org/10.14419/ijet.v6i1.6657.
Повний текст джерелаАнотація:
The importance of line Ngo-Brazzaville (220 kV, 207 km) requires operators to avoid cuts that can increase the risk of instability. We see it is quite rare that a storm that occurs in areas crossed by this line will not cause triggering. Note that due to lightning discharges are the main causes of unscheduled outages of Congo's power lines; we ignore this during the peak values of voltage wave forms that result. In regions with high level keraunic like Congo, reducing insulation failures due to lightning is a concern in the management of overheads lines. This article clarifies the peak values of the voltages that can be achieved on the network in order to build the operators as to the precautions on the insulation coordination of protective equipment related to lightning. For these calculations surge of atmospheric origin (case of lightning), we considered the bi-exponential function and Heidler function for modeling the wave of the lightning current. This methodology led us to specially treat the effects of direct lightning strikes that constitute the worst case because they generate most destructive shock wave that indirect lightning strikes.
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Rodger, C. J., S. Werner, J. B. Brundell, E. H. Lay, N. R. Thomson, R. H. Holzworth, and R. L. Dowden. "Detection efficiency of the VLF World-Wide Lightning Location Network (WWLLN): initial case study." Annales Geophysicae 24, no. 12 (December 21, 2006): 3197–214. http://dx.doi.org/10.5194/angeo-24-3197-2006.
Повний текст джерелаАнотація:
Abstract. An experimental Very Low Frequency (VLF) World-Wide Lightning Location Network (WWLLN) has been developed through collaborations with research institutions across the world, providing global real-time locations of lightning discharges. As of April 2006, the network included 25 stations providing coverage for much of the Earth. In this paper we examine the detection efficiency of the WWLLN by comparing the locations from this network with lightning location data purchased from a commercial lightning location network operating in New Zealand. Our analysis confirms that WWLLN favours high peak current return stroke lightning discharges, and that discharges with larger currents are observed by more stations across the global network. We then construct a first principles detection efficiency model to describe the WWLLN, combining calibration information for each station with theoretical modelling to describe the expected amplitudes of the VLF sferics observed by the network. This detection efficiency model allows the prediction of the global variation in WWLLN lightning detection, and an estimate of the minimum CG return stroke peak current required to trigger the network. There are strong spatial variations across the globe, primarily due to station density and sensitivity. The WWLLN is currently best suited to study the occurrence and impacts of high peak-current lightning. For example, in 2005 about 12% of the global elve-producing lightning will have been located by the network. Since the lightning-EMP which produce elves has a high mean rate (210 per minute) it has the potential to significantly influence the ionosphere on regional scales.
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Yanoviak, Stephen P., Evan M. Gora, Jennifer Fredley, Phillip M. Bitzer, Rose-Marie Muzika, and Walter P. Carson. "Direct effects of lightning in temperate forests: a review and preliminary survey in a hemlock–hardwood forest of the northern United States." Canadian Journal of Forest Research 45, no. 10 (October 2015): 1258–68. http://dx.doi.org/10.1139/cjfr-2015-0081.
Повний текст джерелаАнотація:
Lightning strikes millions of trees worldwide each year, yet structured lightning damage surveys are relatively rare. Estimates drawn from the literature suggest that lightning directly or indirectly kills up to 4% of large canopy trees in a stand annually. Lightning is a major cause of death for pines in southeastern US forests and for large cacti in some deserts, but its landscape-level effects exclusive of fire at higher latitudes are poorly known. We quantified damage to trees from lightning and other sources in hemlock–hardwood forests of the Huron Mountain Region of Michigan, USA. This region receives ca. 100 cloud-to-ground lightning flashes per year, with most occurring in May to August. We recorded abiotic and biotic damage on 309 trees distributed among nine transects, each >2 km long. None of the transect trees had lightning scars, and we observed only 14 clear cases of lightning damage among thousands of trees examined during associated meander surveys (each ca. 0.5 ha). This damage was more commonly associated with emergent stature (50% of struck trees) and higher rates of biotic damage (50%) than we observed in the 309 transect trees (22% emergent status and 16% incidence of biotic damage). Nearly all (93%) of the lightning damaged trees were conifers, suggesting that either susceptibility to, or response to, lightning strikes has a phylogenetic basis. These preliminary results provide a foundation for comparative studies in other forests. Accurate quantification of lightning-induced tree mortality will improve forest turnover models and facilitate predictions of future forest structure under conditions of increased lightning frequency.
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Stevenson, Stephanie N., Kristen L. Corbosiero, and John Molinari. "The Convective Evolution and Rapid Intensification of Hurricane Earl (2010)." Monthly Weather Review 142, no. 11 (October 24, 2014): 4364–80. http://dx.doi.org/10.1175/mwr-d-14-00078.1.
Повний текст джерелаАнотація:
Abstract The relationship between an inner-core (r < 100 km) lightning outbreak and the subsequent rapid intensification (RI) of Hurricane Earl (2010) is examined using lightning strikes recorded by the World Wide Lightning Location Network (WWLLN) and in situ observations from various aircraft missions. Moderate (8.4 m s−1) northeasterly deep-layer (850–200 hPa) vertical wind shear, caused by outflow from Hurricane Danielle, existed over Earl at the beginning of a prolonged period of RI. Over 70% of the lightning strikes within a 500-km radius occurred downshear, with a preference toward downshear right in the outer rainbands, in agreement with previous studies. The location of inner-core strikes in Earl differed markedly from previous studies. The inner-core lightning activity precessed from left of shear to upshear, an extremely rare event, beginning just prior to the onset of RI. Diagnosis of the vortex tilt midway through the lightning precession showed this convection was occurring downtilt in the upshear-left quadrant; however, limited observations could not confirm if the vortex tilt was precessing with the lightning. Elevated values of low-level relative humidity and CAPE were also found upshear and supported the inner-core convection, which was found to occur within the radius of maximum wind (RMW). Previous studies have shown that convection located inside the RMW promotes intensification. It is hypothesized that intensification may have occurred in part because the vertical wind shear acted to reduce the upshear tilt, and the occurrence of convection inside the RMW helped to enhance the warm core.
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Jacobson, Abram R., Robert Holzworth, Jeremiah Harlin, Richard Dowden, and Erin Lay. "Performance Assessment of the World Wide Lightning Location Network (WWLLN), Using the Los Alamos Sferic Array (LASA) as Ground Truth." Journal of Atmospheric and Oceanic Technology 23, no. 8 (August 1, 2006): 1082–92. http://dx.doi.org/10.1175/jtech1902.1.
Повний текст джерелаАнотація:
Abstract The World Wide Lighting Location Network (WWLLN) locates lightning globally, using sparsely distributed very low frequency (VLF) detection stations. Due to WWLLN’s detection at VLF (in this case ∼10 kHz), the lightning signals from strong strokes can propagate up to ∼104 km to WWLLN sensors and still be suitable for triggering a station. A systematic evaluation of the performance of WWLLN is undertaken, using a higher-frequency (0–500 kHz) detection array [the Los Alamos Sferic Array (LASA)] as a ground truth during an entire thunderstorm season in a geographically confined case study in Florida. It is found that (a) WWLLN stroke-detection efficiency rises sharply to several percent as the estimated lightning current amplitude surpasses ∼30 kA; (b) WWLLN spatial accuracy is around 15 km, good enough to resolve convective-storm cells within a larger storm complex; (c) WWLLN is able to detect intracloud and cloud-to-ground discharges with comparable efficiency, as long as the current is comparable; (d) WWLLN detects lightning-producing storms with high efficiency in every 3-h epoch; thus, WWLLN can be useful for locating deep convection for weather forecasting on 3-h update cycles; and (e) WWLLN detects a stroke count in each storm that is weakly proportional to the stroke count detected by LASA. Thus, to the extent that lightning rate can serve as a statistical proxy for rainfall, WWLLN may eventually provide rainfall-proxy data to be assimilated in 3-h forecast update cycles.
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Meyer, V. K., H. Höller, and H. D. Betz. "The temporal evolution of three-dimensional lightning parameters and their suitability for thunderstorm tracking and nowcasting." Atmospheric Chemistry and Physics Discussions 13, no. 1 (January 22, 2013): 2217–42. http://dx.doi.org/10.5194/acpd-13-2217-2013.
Повний текст джерелаАнотація:
Abstract. Total lightning (TL) data has been found to provide valuable information about the internal dynamics of a thunderstorm allowing conclusions about its further development as well as indicating potential of thunderstorm-related severe weather at the ground. This paper investigates electrical discharge correlations of strokes and flashes with respect to the temporal evolution of thunderstorms in case studies as well as by statistical means. The recently developed algorithm li-TRAM (tracking and monitoring of lightning-cells, Meyer et al., 2012) has been employed to track and monitor thunderstorms based on three-dimensionally resolved TL lightning data provided as stroke events by the European lightning location network LINET. From statistical investigation of 863 suited thunderstorm life-cycles the cell area turned out to correlate well with (a) the total discharge rate, (b) the in-cloud (IC) discharge rate, and (c) the mean IC discharge height per lightning-cell as identified by li-TRAM. All three parameter correlations consistently show an abrupt change in discharge characteristics around a cell area of 170 km2. Statistical investigations supported by the comparison of three case studies – selected to represent a single storm, a multi-cell and a supercell – strongly suggest that the correlation functions include the temporal evolution as well as the storm type. With the help of volumetric radar data, it can also be suggested that the well defined break observed at 170 km2 marks the region, where the transition occurs from short-lived and rather simple structured single storm cells to better organized, more persistent, and more complex structured thunderstorm forms, e.g. multi-cells and super-cells. All three storm-types experience similar discharge characteristics during their growing and dissipating phases. However, while the poorly organized and short-lived cells preferentially remain small during a short mature phase, mainly the more persistent thunderstorm types develop to sizes above 170 km2 during a pronounced mature stage. At that stage they exhibit on average higher discharge rates at higher altitudes as compared with matured single-cells. With the maximum stroke distance set to 10 km and a flash duration set to 1 s the parameterisation functions found for the stroke rate as function of the cell area has been transformed to a flash rate. The presented study suggests that, with respect to the storm type, stroke and flash correlations can be parameterized. There is also strong evidence, that parameterization functions include the time parameter, so that altogether TL stroke information has good potential to pre-estimate the further evolution (nowcast) of a currently observed storm in an object-oriented thunderstorm nowcasting approach.