Effects Of Lightning Research Articles

Simulation analysis of complex electromagnetic environment effect of helicopter engine

With the improvement of equipment informatization, the adaptability of complex electromagnetic environment of airborne engine equipment is becoming increasingly important. The mechanism and degree of influence of complex electromagnetic environment on engine are quite different, which has seriously threatened flight safety. In order to predict and analyze part of electromagnetic environment faced by airborne engine, FEKO electromagnetic simulation software is used for simulation research. According to the relevant test methods of SAE-ARP5416, SAE-ARP5412, GJB-1389A and other standards of American Society of engineers, the field strength and cable coupling of airborne engine under lightning effect and high field intensity irradiation are predicted by simulation. The conclusion has certain guiding significance for further research on complex electromagnetic field protection of engine.

Analysis of carbon fiber destruction by lighting current

The paper considers the unique properties of conducting carbon fiber composite: specific resistivity at different directionality of layers and critical energy of layering and destruction on the basis of experimental data. High mechanical strength and low specific gravity are noted, allowing its use in aircraft engineering to improve aircraft tactical and technical data of aerial vehicles. Strong anisotropy of electrically-conductive properties affects current spreading through carbon fiber and leads to significant destruction of the material. Theoretical analysis of lightning current spreading along anisotropic-conducting material in the form of extended plate was carried out on the basis of two proposed models of carbon fiber destruction by lightning currents. For the first continuum model an exact analytical solution to the Laplace equation with Neumann boundary conditions via the Greenberg method was found. The criteria for composite destruction was found, and the radius and depth of destruction of a conductive material by lightning current were calculated. Layer-by-layer destruction is considered on the basis of carbon fiber equivalent circuit. The strong anisotropy of the material resulting in the release of full energy in the first layer is taken into account. It is shown that the destruction of the top layer changes the distribution of currents over the remaining layers. The results of numerical modeling of layer-by-layer destruction of carbon fiber for different number of layers are given. The conclusion on the application of criteria to forecast the lightning effects and optimize lightning at the stage of aircraft design is made.

A mechanistic and empirically supported lightning risk model for forest trees

AbstractTree death due to lightning influences tropical forest carbon cycling and tree community dynamics. However, the distribution of lightning damage among trees in forests remains poorly understood.We developed models to predict direct and secondary lightning damage to trees based on tree size, crown exposure and local forest structure. We parameterized these models using data on the locations of lightning strikes and censuses of tree damage in strike zones, combined with drone‐based maps of tree crowns and censuses of all trees within a 50‐ha forest dynamics plot on Barro Colorado Island, Panama.The likelihood of a direct strike to a tree increased with larger exposed crown area and higher relative canopy position (emergent > canopy >>> subcanopy), whereas the likelihood of secondary lightning damage increased with tree diameter and proximity to neighbouring trees. The predicted frequency of lightning damage in this mature forest was greater for tree species with larger average diameters.These patterns suggest that lightning influences forest structure and the global carbon budget by non‐randomly damaging large trees. Moreover, these models provide a framework for investigating the ecological and evolutionary consequences of lightning disturbance in tropical forests.Synthesis. Our findings indicate that the distribution of lightning damage is stochastic at large spatial grain and relatively deterministic at smaller spatial grain (<15 m). Lightning is more likely to directly strike taller trees with large crowns and secondarily damage large neighbouring trees that are closest to the directly struck tree. The results provide a framework for understanding how lightning can affect forest structure, forest dynamics and carbon cycling. The resulting lightning risk model will facilitate informed investigations into the effects of lightning in tropical forests.

Analysis of Metal Oxide Varistor Arresters for Protection of Multiconductor Transmission Lines Using Unconditionally-Stable Crank–Nicolson FDTD

Surge arresters may represent an efficient choice for limiting lightning surge effects, significantly reducing the outage rate of power lines. The present work firstly presents an efficient numerical approach suitable for insulation coordination studies based on an implicit Crank–Nicolson finite difference time domain method; then, the IEEE recommended surge arrester model is reviewed and implemented by means of a local implicit scheme, based on a set of non-linear equations, that are recast in a suitable form for efficient solution. The model is proven to ensure robustness and second-order accuracy. The implementation of the arrester model in the implicit Crank–Nicolson scheme represents the added value brought by the present study. Indeed, its preserved stability for larger time steps allows reducing running time by more than 60 % compared to the well-known finite difference time domain method based on the explicit leap-frog scheme. The reduced computation time allows faster repeated solutions, which need to be looked for on assessing the lightning performance (randomly changing, parameters such as peak current, rise time, tail time, location of the vertical leader channel, phase conductor voltages, footing resistance, insulator strength, etc. would need to be changed thousands of times).

Analysis of lightning surge influence on ukrainian electric network power lines

The article discusses the impact of lightning surges on overhead lines. The possible effects of lightning in different elements of the overhead lines. Proposed solutions to the problems that arise as a result of a lightning strike to the overhead line. Provided that the source of the lightning overvoltage is the natural electricity of the thunderstorm clouds, which in the form of lightning to hit targets on the ground. It is shown that the wave surge occurring in the current-carrying parts when lightning strikes, distributed, penetrating into the windings of transformers, machines, affecting the insulation lines and equipment. The time of exposure to atmospheric overvoltage is very small (from a few to hundreds millionths of a second), but the magnitude of these overvoltages in the absence of special measures of protection may reach millions of volts. It is proved that the main danger for the line is a direct lightning strike to the phase conductor, with subsequent overlap of insulation from over-voltages that occur at the same time. After the end of the lightning current pulse in the overlap remains the leading channel with the gas, which had not deansoffice, which under the action of operating voltage may continue to leak current of industrial frequency. In the process of elimination of the fault line caused by lightning, consumed the life of the switches; transformers and other network equipment are subjected elektrodynamik and thermal action of short circuit currents. A significant part of the circuit is followed by the development of the accident that requires a trip line for a long time with the disruption of the normal supply. The probability of a storm off of a line depends on many factors: the intensity of storm activity in the areas along the highway line, the nominal voltage of the network, its design, material of supports etc. Shown that the effectiveness of lightning protection is determined separately for the estimated cases of damage of the line. The proposed actions, determining the effectiveness of lightning protection is calculated separately for cases of damage and which is capable of preventing direct lightning strikes to the protected objects and to organize the flow of lightning currents at a safe way. Define a single space lines, which require additional protection measures.

Examination of Shielding Effectiveness on Al6061 Composite Material Reinforced with Fly Ash for Oblique Incidence

Over last two decades a high extent of concentration is on reducing the weight of the commercial aircraft with enough mechanical properties like strength, stress etc. Composite materials are preferable for construction aircrafts with less weight and good mechanical properties. But these composite materials have very less conductivity, suppose if the lightning strikes the aircraft flow of current through exit terminals of it was not possible, so there is a possibility for physical damage of the aircraft. To overcome the lightning effect on aircraft lightning strike protection (LSP) should be involved, for that in the present work AL6061 composite was considered for the construction of aircraft. To improve the shielding and mechanical properties of the material, fly ash particles are reinforced at different percentages. Electromagnetic shielding and mechanical properties are measured for the above material at X band. MATLAB Simulation results are compared with the conventional AL6061 composites for arbitrary case.

Scientific Goals and In-orbit Performance of the High-energy Particle Detector on Board the CSES

Abstract The China Seismo-Electromagnetic Satellite (CSES) aims to monitor electromagnetic, particle, and plasma perturbations in the iono-magnetosphere and inner Van Allen radiation belts originated by electromagnetic sources external and internal to the geomagnetic cavity, cosmic rays, and solar events. In particular, the objective of the space mission is to investigate lithosphere–atmosphere–ionosphere coupling mechanisms (including the effects of lightning, earthquakes, volcanoes, and artificial electromagnetic emissions) that induce perturbations of the top side of the ionosphere and lower boundary of the radiation belts. To this purpose, the mission has been conceived to take advantage of a multi-instrument payload comprising nine detectors for the measurement of electromagnetic field components, plasma parameters, and energetic particles, as well as X-ray flux. The Italian team participating in the CSES mission has built one of these devices, the High-Energy Particle Detector (HEPD), for high-precision observations of electrons, protons, and light nuclei. During its trip along the orbit, and thanks to the large set of detectors operated on board, CSES completely monitors the Earth, acting as an excellent instrument for space weather. The satellite was launched on 2018 February 2, with an expected life span of 5 yr. This article describes the CSES mission with a particular focus on the HEPD apparatus and its in-flight performance.

Evaluation method for lightning damage of carbon fiber reinforced polymers subjected to multiple lightning strikes with different combinations of current components

The aircraft lightning environment consists of four lightning current components with different parameters, which are known as lightning components A, B, C and D. The lightning damage of aeronautic carbon fiber reinforced polymer laminates subjected to multiple continuous sequential lightning current components with different timing combinations was experimentally evaluated. The experimental results indicated that the carbon fiber reinforced polymer laminates suffered serious lightning damage, including carbon fiber fracture, resin pyrolysis and delamination. Through an analysis of the lightning damage properties of carbon fiber reinforced polymers, the influential factors and evaluation methods of the lightning damage in carbon fiber reinforced polymer laminates were studied. Because the lightning damage evaluation method under a single lightning impulse was found to be inapplicable for the multiple continuous lightning strikes, a multi-factor evaluation method was proposed. In the multiple continuous lightning strike test, the damage depth was found to be closely related to lightning components A, B and D and could be estimated based on the amplitudes and rise rates of the applied lightning components. Increases in the damaged area after a lightning strike were driven by lightning component C due to its substantial thermal effects. The damaged area was evaluated on the basis of the parameters of the electrical action integral and the transfer charge. The research on the evaluation methods for carbon fiber reinforced polymer laminate lightning damage presented herein may provide experimental support and a theoretical basis for studying the lightning effect mechanism and optimizing material formulations, manufacturing processes and structural designs to achieve performance improvements for carbon fiber reinforced polymer laminates in the future.

A novel hybrid method based on teaching–learning algorithm and leader progression model for evaluating the lightning performance of launch sites and experimental tests

In this article, a numerical optimization method has been used to study the lightning effect on satellite launch sites. In the conventional direct method, the leader progression model along with charge simulation method is employed for all the lightning leader tip positions and all the possible lightning current values on the equipment. This time-consuming calculation set is reduced in the developed method by using an optimization algorithm. For this purpose, the specifications of a real air termination system have been used for simulation and a system in a laboratory scales has been used for both purposes of simulation and practical tests. Teaching–learning-based optimization (TLBO) algorithm has been employed as an intelligent method to find the number of lightning strikes to the equipment, to detect critical areas on the structure surface and to reduce the execution time. Also, some experimental tests conducted in a high-voltage laboratory are referred on the small-scale system to investigate the conditions of leaders inception and propagation. An appropriate adaptation between the simulation results of TLBO and conventional direct method verifies the application of this method to investigate the performance of other air termination systems.

Lightning Protection Systems Suitable for Stables: A Case Study

The evolution of climate and of electrical devices are raising users’ awareness about the protection of structures and plants against common overvoltage phenomena and those ones of atmospheric origin. Therefore, a continuous evolution of thunderstorm phenomena, increasingly concentrated and intense, is occurring. Conversely, electric devices are increasingly being equipped with electronics indispensable for their right functioning and are very sensitive to electromagnetic phenomena of an induced and conducted nature. In Italy, the law concerning work health and safety compels employers to assess the risk raised by lightning and to ensure that buildings, systems, structures, and equipment are protected from the effects of lightning in agreement with national and international technical standards. In the agricultural livestock sector, the new guidelines of agricultural policy in Italy requires farms to re-examine their structures, in particular the compatibility with animal protection requirements. In the event of a fault, the electric circuit must be interrupted in times not higher than expected and, in particular in the agricultural and zootechnical structures, it is necessary to maintain the contact voltages to negligible values by carrying out additional equipotential connections among the masses and with foreign masses that can be touched. Furthermore, particular attention is required in limiting the step voltage to which animals are particularly sensitive to, by connecting the electro-welded metal grids, which are commonly located under the concrete floor of animal shelters, to the earth collector. Taking in mind the aforesaid, the aim of this work was to analyze the technical standard concerning the protection from lightning with reference to the agricultural livestock sector and the study of the salient components to set up a suitable lightning protection system for a medium-sized stable.

Electromagnetic interference shielding in unmanned aerial vehicle against lightning strike

Electromagnetic interference (EMI) due to lightning strike in Unmanned Aerial Vehicle (UAV) became a critical issue, since it could cause a severe damaged to electronic equipment which was installed in UAV. This paper proposed a method to reduce EMI by creating shield over the body of UAV with aluminum foil with thickness 0.15mm. A standard lightning impulse-voltage generated by impulse generator was delivered to the high voltage (HV) electrode at a particular distance from UAV. Indirect effect of lightning strike was investigated by measuring induced voltage inside the compartment of UAV fuselage during flashover between the HV electrode and UAV. Flashover between the HV electrode and UAV simulated the lightning strike. The result showed that the highest voltage only 1V at UAV compartment when 150kV impulse voltage supplied to the electrode with striking area on the wing. The measured voltage was far below 100V as the insulation level of low voltage equipment inside UAV. Although the direct effect of lightning has created a burning hole on the surface aluminum foil with thickness 0.15mm, the effect was overcome by increasing the thickness to 0.3mm. The application of aluminum foil over the surface of UAV repelled the electromagnetic interference which acted as a Faraday cage. The shielding method was successfully reduced the effect of EMI.

An Improved Antenna Theory Model of Lightning Return Stroke Using a Distributed Current Source–Part II: Applications

A full-wave method of Maxwell's equations is adopted for the analysis of lightning electromagnetic fields. The method is based on a numerical solution of the electric field integral equation by the method of moments (MoM). A new electromagnetic model of the lightning channel based on a thin-wire antenna with distributed current sources allows the use of Sommerfeld integrals for the evaluation of electromagnetic fields due to lightning, in stratified media. In order to extend the study to more complex systems including the lightning channel and its nearby structures, an array of conducting wires and metallic surfaces is used to represent the entire system. An efficient and cost-effective MoM method capable to compute the variation of spatial one-dimensional linear currents and two-dimensional surface currents is implemented. It permits the evaluation of the electromagnetic interference effects of lightning in a complex environment, without the use of approximate formulas. The proposed method is capable of analyzing the electromagnetic interference effects of lightning for a wide range of applications. Several case studies, including the analysis of lightning-induced disturbances on overhead lines, underground cables, and shielding enclosures, are also presented.

Effects of Lightning on the Magnetic Properties of Volcanic Ash

High-current impulse experiments were performed on volcanic ash samples to determine the magnetic effects that may result from the occurrence of volcanic lightning during explosive eruptions. Pseudo-ash was manufactured through milling and sieving of eruptive deposits with different bulk compositions and mineral contents. By comparing pre- and post-experimental samples, it was found that the saturation (i.e., maximum possible) magnetization increased, and coercivity (i.e., ability to withstand demagnetization) decreased. The increase in saturation magnetization was greater for compositionally evolved samples compared to more primitive samples subjected to equivalent currents. Changes in remanent (i.e., residual) magnetization do not correlate with composition, and show wide variability. Variations in magnetic properties were generally more significant when samples were subjected to higher peak currents as higher currents affect a greater proportion of the subjected sample. The electrons introduced by the current impulse cause reduction and devolatilization of the ash grains, changing their structural, mineralogical, and magnetic properties.

Electromagnetic effect of lightning return stroke to buried energy pipelines

Direct lightning strike in the vicinity of buried high-pressure energy pipeline can cause damages to pipe coatings or to the metal pipe. This damage sometimes leads to explosions which may cause loss of consignments. This is also a risk to pipeline integrity and safety of the people working on the pipeline. Hence, lightning induced electromagnetic interference (EMI) on buried energy pipeline is a matter of serious concern. To protect buried metallic energy pipeline from the effects of direct lightning strikes near the pipeline to the ground, it is necessary to have comprehensive information about the lightning currents and the radiated electromagnetic fields. To obtain thorough information of lightning-induced effect on the buried pipeline, a computational model considering electrical parameters of soil, pipe and lighting strikes to carry out a simulation of buried pipeline under soil has been developed which can be used to identify parameters influencing the coupling phenomenon between pipeline and lightning strike. The E and H field was estimated at various distance and depth from the point of strike. The model is based on the finite difference time domain (FDTD) solution of Maxwell’s equations. Lightning current and other fields are calculated within soil with and without the presence pipe and the same has been done for pipe with and without corrosion coating. The results are then used to analyze the influence of various parameters of the studied system on the development of high breakdown potential around the pipeline. This paper then presents the impacts of the direct lightning strike to the ground on buried metallic energy pipeline with corrosion coating. The results showed that although ground conductivity, current rise time, burial depth of pipeline and the pipeline metallic property has an influence on the severity of impact, in case of coated pipe, the coating on pipeline plays a great role on the scale of impact lightning can cause on the pipeline. While coating prevents pipelines from corrosion, the very low conductive coating is also responsible for very high electric field above the pipe surface. This work will be very useful pipeline industry in selecting a coating with suitable impedance value so that buried pipeline can be protected from both corrosion and lightning strike.

Lightning Effects Technique Comparison in Unity 3D

Game developer team especially indie game developer mostly has small number of members and sometimes unbalanced team composition. Sometimes it has more artist than programmer, sometimes it is the opposite. At the same time, consumer will choose game that has a beautiful graphics. This demands of good graphic game can cause problem to unbalanced developer team. Therefore it is needed to know techniques that can utilize many artist or many programmer to create good graphic games. In this articles, we introduce some techniques to create special lightning effects of characters skills in Unity3D. Some of them can be created with good artistic skill. It means that this technique make use of your artist. The other technique created procedurally using Line Renderer from Unity 3D. This technique is friendly for artist since it utilze programmer. At the end of this article, all of those technique will be tested in their performance of its lightness and speed.

Reducing the Effect of Lightning on Step and Touch Voltages in a Grounding Grid Using a Nature-Inspired Genetic Algorithm With ATP-EMTP

This paper discusses the step and touch voltages, based on body resistance, in a grounding grid after a lightning strike at a 434-/21-kV substation. To ensure grounding grid safety, the maximum step and touch voltage should not exceed the safety criteria defined by the IEEE Std. 80. In this paper, ATP-EMTP and a genetic algorithm are used to analyze and optimize the step and touch voltages in a power grid. The voltages are calculated under normal conditions of a lightning strike at a power system. Thevenin’s theorem is applied to calculate the step and touch voltages. The genetic algorithm is applied in ATP-EMTP to obtain the minimum level of step and touch voltages in the grounding grid after lightning strikes the power system. The step and touch voltages at different positions of the grounding grid are explained in this paper using the ATP-EMTP and the genetic algorithm. The computer simulation shows that the proposed scheme is highly feasible and technically attractive.

Damage Characteristics of CFRP Laminates Subjected to Multiple Lightning Current Strike

The lightning damage depths and areas of carbon fiber reinforced polymer (CFRP) laminates subjected to multiple continuous sequential lightning current components with different timing combinations were experimentally evaluated. The experimental results indicated that the CFRP laminates suffered serious lightning damage, including fracture of the carbon fibers and layer delamination. After a multiple lightning strike composed of lightning components A, B and C, the surface temperature of the CFRP laminates, which was projected from the measured temperature with lower magnitude, can exceed 1600 °C. The damage area and depth were approximately 2790 mm2 and 1.28 mm in the “ABCD” test mode. The damage depth was found to be closely related to lightning components A, B and D, which are accompanied by the shockwave and the overpressure effect, the dielectric breakdown effect and the local thermal effect. The increases in the surface temperature and damage area after lightning strike were mainly affected by the lightning component C with substantial thermal effect. The application sequence and material properties are important factors for evaluating the damage effect of the newly added lightning component on samples that have suffered from multiple continuous lightning components. The influencing factors and analysis method for CFRP laminate lightning damage subjected to multiple continuous sequential lightning components may provide both experimental support and a theoretical basis for studying the mechanism of the lightning effect and the refinement and improvement of a lightning direct effect test method for CFRP laminates in the future.

Simulation analysis on return conductor configuration for lightning indirect effect test of metal cylinder

Objectives In order to study the lightning indirect effect of metal cylindrical ordnance, a method for constructing the tester for lightning indirect effect of the metal cylindrical flying object is studied, and a cage type frame similar to coaxial line is designed as the coupling device. Methods Firstly, the current resonance of system is analyzed by observing the current waveform of different terminators. Then, through the electromagnetic simulation software CST, the surface current distribution of the metal cylinder is simulated, and the influences of different load impedance and different return conductor arrangement on the uniformity of surface current distribution are analyzed. Finally, according to the simulation results, the surface current intensity of cylinder and the instantaneous electromagnetic field distribution inside and outside the cylinder are analyzed. Results The simulation results show that the cage type injection device similar to coaxial line can be used for indirect lightning effect test of metal cylinders. Conclusions The simulation results provide a basis for the further test.

De Falla's Hungarian Success: A háromszögletű kalap (1928)

Abstract In this study, I examine a hitherto completely unknown subject: the Hungarian reception of Manuel de Falla's ballet pantomime, El sombrero de tres picos (The three-cornered hat). As I point out, the story of the piece began well before Falla composed his music: Alarcón's novel was published in a Hungarian translation just two decades after the Spanish original. In the first decades of the twentieth century, the Budapest Opera House (Magyar Állami Operaház) and Municipal Theatre (Városi Színház) developed intensive opera, theatre, and ballet seasons, in association with the main European capitals during the first decades of the twentieth century. De Falla's ballet was premiered in Budapest in 1927 by Diaghilev's Russian Ballet, in the Municipal Theatre under the Hungarian title A háromszögletű kalap. The piece had such success that it had to be repeated three times. What is more, a Hungarian production was premiered in the Budapest Opera House one year later and this production continued until 1963, delivering a total of 75 performances. The sources (among others the handwritten performing scores) of this latter production preserved in the National Széchényi Library and in the Archives of the Hungarian State Opera House reveal an intense work of choreographic adaptation, along with careful design of staging, costumes, lightning, and scenery effects, all accomplished by great international personalities to make this very Spanish ballet understandable to the Magyar audience. Falla's work also found a significant support in the press, highlighting both the plot's universality and the expressiveness of his music, which had made it a Hungarian success.

Experimental Simulation of Lightning Current Discharge on Rocks

Lightning is a transient, high-current discharge occurring within a thundercloud, between clouds, or between a cloud and the ground. Cloud-to-ground (CG) lightning is the most studied because of its impact on human life. The aim of this study is to elucidate the effects of lightning in Earth materials by simulating the lightning current discharges in a laboratory setting. Technical applications of this work include the study or development of customized materials used to prevent accidents, limit damage, or reduce interruptions in electrical power system owing to lightning strikes, such as lightning arresters or high-voltage fuses. High-voltage electrical arcs were discharged through rock specimens, and power, energy, and duration of discharge were estimated to provide a better understanding of the origin of naturally occurring fulgurites (shock-impact glasses) and the lightning/rock interaction. X-ray powder diffraction showed that the samples used for the experiment represent basalt (samples A0, A1–A4) and granite (samples B1, B2). Optical microscopy provides direct evidence that materials can be physically altered due to the heat generated by an arcing event. Optical microscopy observations showed that arcs passed through the target rocks and mimicked the effect of lightning strikes hitting the surface of the rock, melting the target rock, and passing to ground. Fulgurite glass observed on basalt samples shows the impact origin lining the surface of millimeter-size craters and a slash-like coating, whereas in the granite sample, the fulgurite was not observed because the arc passed directly to the laboratory ground. Significant differences in the duration of the experimental electrical arcs that passed through dry and wet samples (A1 and A3; A2 and A4, respectively) were observed. This discrepancy can be ascribed to the variation of the electrical properties related to the distribution of the water layer on the rock sample and to the occurrence of magnetite grains, which may increase the local conductivity of the sample owing to its electromagnetic properties.