Lightning Simulation Research Articles

Assessment of lightning damage of OGW by comparing natural effects and the common Joule heat & arc heat model application

Acquisition and analysis of the thermal damage and injected energy data of the natural lightning strikes are conducive to understand the lightning-induced damage mechanism of OGW (Overhead Ground Wire) as well as guide the improvement of the lightning simulation experimental methods in the laboratory. In this paper, a rupture accident of OGW in the power grid, which was taken as a natural lightning strike damage experiment, was used to compare the thermal damage and the injected energy with the existing common Joule heat & arc heat transfer model. The results indicated that the thermal damage of the common model is milder than that of natural lighting strike. In this accident, at least more than 45% of the injected natural lightning energy was not sourced when adopting the existing common model to simulate the thermal damage of OGW, even after considering the electrons enthalpy flux that is usually neglected in calculation.

The Effect of Rainfall and Illumination on Automotive Sensors Detection Performance

Vehicle safety promises to be one of the Advanced Driver Assistance System’s (ADAS) biggest benefits. Higher levels of automation remove the human driver from the chain of events that can lead to a crash. Sensors play an influential role in vehicle driving as well as in ADAS by helping the driver to watch the vehicle’s surroundings for safe driving. Thus, the driving load is drastically reduced from steering as well as accelerating and braking for long-term driving. The baseline for the development of future intelligent vehicles relies even more on the fusion of data from surrounding sensors such as Camera, LiDAR and Radar. These sensors not only need to perceive in clear weather but also need to detect accurately adverse weather and illumination conditions. Otherwise, a small error could have an incalculable impact on ADAS. Most of the current studies are based on indoor or static testing. In order to solve this problem, this paper designs a series of dynamic test cases with the help of outdoor rain and intelligent lightning simulation facilities to make the sensor application scenarios more realistic. As a result, the effect of rainfall and illumination on sensor perception performance is investigated. As speculated, the performance of all automotive sensors is degraded by adverse environmental factors, but their behaviour is not identical. Future work on sensor model development and sensor information fusion should therefore take this into account.

Validation of Lightning Simulation Compared With Measurements Using DCI Technique Post-Processed to be Applied to a Lightning Threat

The direct current injection (DCI) technique is a complicated method which involves both a testing campaign and electromagnetic simulations. Consequently, it takes a long time, entails high costs, and requires a lot of effort in a complex post-process. The present article shows that only with the lightning simulations, also involved in the DCI process, similar and useful information can be obtained. Currents induced on cables in a lightning simulation on an aircraft cockpit are compared with the postprocessed results coming from a low-level DCI test, demonstrating good agreement within the established margin, and analyzing the identified differences. This example illustrates the benefits of using simulations in reducing costs and delivery time. We also show their potential benefit in improving the aircraft safety by using them from the earlier stages of the design to the end of service of the aircraft. This is achieved thanks to their capability to predict the behavior of the object in configurations which could not be addressed by test, and by checking a larger number of probes, which could even be placed in non-accessible areas.

An Improved Parametric Method for Selecting Different Types of Tesla Transformer Primary Coil to Construct an Artificial Lightning Simulator

Due to the intermittent and hazardous nature of lightning impulse, researchers rely on artificial impulse generators to study it. The Tesla coil is a commonly used device to generate artificial lightning. This paper presents a parametric analysis of the primary side coil of the Tesla transformer. The analysis employs seven key electrical properties: skin depth, current density, voltage distribution, Ohmic loss, electric field strength, charge density, and energy content. These parameters are used to evaluate the response of various coil types to high voltage impulses. The Ansys high-frequency electromagnetic solver is used to perform a comparative analysis of essential parameters. The results can aid lightning researchers and Tesla coil designers in determining the optimal designs for Tesla primary coils in the future. The analyzed data is validated using Tesla coil hardware, which is used as an artificial lightning producer to test the feasibility of a lightning energy harvester.

Calculation of reservoir fracture network propagation based on lightning breakdown path simulation

<p indent="0mm">Hydraulic fracturing produces fractures with high conductivity and forms a complex fracture network, which supports the economic development of unconventional reservoirs. Describing a fracture network is the basic premise for fracturing evaluation and production simulation. This study analyzes the lightning breakdown path simulation method and adopts the principle of similarity to comprehensively consider the reservoir geological parameters, <italic>in situ</italic> stress distribution, and fracturing construction parameters; the results are used to develop a new fracture simulation method. In the proposed method, circumferential stress and critical fracture stress are used to determine the extension range of secondary fractures, and random function and fractal probability index are introduced to characterize the random distribution of the fracture extension. Then, an actual production well fracture network with microseismic monitoring data is simulated. The results show that the proposed simulation method can accurately describe the fracture network with a high degree of matching in the range covered by the microseismic data. In addition, the influences of the <italic>in situ</italic> stress difference gradient, initial injection pressure, and fractal probability index on the fracture morphology are analyzed. This research shows that a smaller <italic>in situ</italic> stress difference gradient relates to greater fracturing fluid injection pressure and smaller fractal probability index and fracturing fluid viscosity, which facilitates the formation of more branch fracture network systems. Finally, the proposed method is applied to the simulation of a fracture network in two wells. The results show that the inverted fracture morphology is consistent with the distribution range of microseismic data. The simulation of 94 clusters of fractures in 32 sections of well X2 shows that the fracture branches of the well are obviously developed, which indicates a generally complex fracture network. The transverse communication of the single wing fracture network is about <sc>200 m,</sc> and the longitudinal communication is about <sc>20 m.</sc> Therefore, the calculation method of fracture network propagation based on lightning simulation can consider the uncertainty in the fracture propagation direction, particularly when the reservoir geological characteristics are unclear. Moreover, it provides a new method for simulating hydraulic fracture propagation.

Evaluation of Different Storm Parameters as the Proxies for Gridded Total Lightning Flash Rates: A Convection-Allowing Model Study

Lightning simulation is important for a variety of applications, including lightning forecast, atmospheric chemical simulation, and lightning data assimilation. In this study, the potential of five storm parameters (graupel volume, precipitation ice mass, radar echo volume, maximum updraft, and updraft volume) to be used as the proxy for the diagnosis of gridded total lightning flash rates has been investigated in a convection-allowing model. A mesoscale convective system occurred in the Guangdong province of China was selected as the test case. Radar data assimilation was used to improve the simulation accuracy of the convective clouds, hence providing strong instantaneous correlations between observed and simulated storm signatures. The areal coverage and magnitude of the simulated lightning flash rates were evaluated by comparing to those of the total lightning observations. Subjective and the Fractions Skill Score (FSS) evaluations suggest that all the five proxies tested in this study are useful to indicate general tendencies for the occurrence, region, and time of lightning at convection-allowing scale (FSS statistics for the threshold of 1 flash per 9 km2 per hour were around 0.7 for each scheme). The FSS values were decreasing as the lightning flash rate thresholds used for FSS computation increased for all the lightning diagnostic schemes with different proxies. For thresholds from 1 to 3 and 16 to 20 flashes per 9 km2 per hour, the graupel contents related schemes achieved higher FSS values compared to the other three schemes. For thresholds from 5 to 15 flashes per 9 km2 per hour, the updraft volume related scheme yielded the largest FSS. When the thresholds of lightning flash rates were greater than 13 flashes per 9 km2 per hour, the FSS values were below 0.5 for all the lightning diagnostic schemes with different proxies.

Everything That Shines Sees: Flash Light, Photography and the Acheiropoietic.

This exposition takes a close look at the concepts of self-origination and mediation for a better understanding of the photographic image engendered by a flash of light and its natural radiation. Starting from my own artistic experiments with fulguric and cosmic rays, performed in cooperation with a lightning simulation lab in Oxfordshire (UK) and with the nuclear research centre CERN in Geneva (Switzerland), it puts forward a speculative approach that looks beyond static and traditional assumptions about what it entails to 'be photographic'. Through the exploration of the creative role fulfilled by a sudden burst of light across different time periods and different manifestations (fulgurites, imprints, photograms, sound), focus is laid on the part the acheiropoieton can play in this revitalized apprehension of the photograph as a technical image and of the agencies involved in its mediation. The research projects discussed thus aim to foreground the involvement of nonhuman contributors in the formation of contemporary images and their epistemology as a possible way to re-think perception in a time increasingly shaped by a reliance on (artificially induced) visibility.

On the Simulation of Lightning and Flash Flood Producing Thunderstorms in the Northeastern Bangladesh

This study is an attempt to simulate the tropospheric conditions associated with lightning and thunderstorms, which occurred during 28-30 March 2017 over northeastern Bangladesh using WRF model. At Sylhet, rainfall amounts of 119 mm and 134 mm are found to occur on 29 March and 31 March 2017 respectively. The continuous very heavy rainfall has been responsible for the devastating flash flood in Sunamganj and adjoining areas in 2017. The study shows that forecasting of lightning and flash flood producing thunderstorms is possible by analyzing different meteorological parameters simulated by WRF Model. The simulated parameters are rainfall, sea level pressure, geopotential height (m), Convective Available Potential Energy (CAPE), winds at various tropospheric levels, cloud water mixing ratio and ice water mixing ratio, vorticity and x, y, z wind components. A low pressure area and strong circulations are found to develop over West Bengal and adjoining Bangladesh with extended troughs towards northeast, having strong flows of southwesterly to southsoutheasterly winds distinctly visible at low level over the Bay of Bengal and Bangladesh. Interaction of northwesterly flows of winds at 500 hPa level and southerly flow coming from the Bay of Bengal is found to produce sufficient instability in the troposphere to develop severe thunderstorms which when moved over northeast Bangladesh/Meghalaya have become stronger due to orographic influence, thereby become lightning and flash flood producing thunderstorms. The thunderstorms become more marked due to the presence of westerly jet stream of 40 ms-1 over Bangladesh and India. The persisting characteristics of the circulation over West Bengal and Bangladesh, the micro-circulation, the intense geopotential low at 850 hPa and their eastward extension have been responsible for continuous heavy to very heavy rainfall over Sylhet and Meghalayan region, causing wide-spread intense flash floods over there. On 29 March 2017, cloud water mixing ratio is found to range from 160 to 1100 mgm-3 and ice water mixing ratio from 27 to 100 mgm-3 at different locations. The maximum cloud water mixing ratio values are 1100 and 1000 mgm-3 at Cherrapunji and Sylhet respectively, where torrential rain has occurred. The high values of cloud water mixing ratio and ice water mixing ratio in the upper troposphere over northeastern Bangladesh and adjoining areas indicates significant convection in the troposphere and have been responsible for moderate to severe lightning. The distribution of CAPE has also shown increasing higher values, indicating moderate to severe lightning.&#x0D; Journal of Engineering Science 11(1), 2020, 133-146

Hygienic and Ecological Justification of Natural Light Transportation System in the City of Tyumen

This paper performs the assessment of the effectiveness of organization of natural light transportation in Tyumen Region, describes the primary natural light transportation systems: light lanterns, solar tents, glass roofs, Solarspot systems, light wells; determinates advantages and disadvantages of natural light transportation systems implementation, analyses the results of simulation of upper, lateral and combined lightning and measurements and assessment of the illumination and the coefficient of natural illumination, as well as studies on the light transmission ability of corrugated glass under the open sky; using hygienic and ecological arguments, justifies the usage of natural light transportation for the city of Tyumen; considers the possibility of the installation of mirrors for Tura River embankment.

Prototyping a RF signal-based lightning warning device using with Internet of Things (IOT) integration

Lightning had caused at least 25, 000 deaths worldwide each year. The study aims to investigate the induced voltage generated by lightning strikes using a lightning detector. Proteus software was employed to simulate the main board of the lightning detector before fabrication. The lightning detector was designed as a radio frequencies receiver and it was tuned to the level (300 kHz to 500 kHz) which enabled it to receive signals from lightning strikes. A lightning simulator was designed using various resistance (100 Ω to 200 Ω) to test the functionality of a lightning detector in order to validate the accuracy of the proposed model. This lightning detector could be activated whenever a small induced voltage (0.2 V and above) were generated by lightning events occurred within 10 km from the detector. This detector captures both the induced voltage and the time difference detected lightning discharge and its sound for further analysis. The time to thunder method was employed to find the estimated lightning discharges distances in parallel to this system in order to validate the current lightning detector. The accuracy of the lightning detector was found to be 88.03%.The analysed data were delivered to the user’s smartphone using cloud system

Simulation Study on Positive Corona Discharge of Receptors on Rotating Wind Turbine Blade Tips under Thundercloud Electric Fields

Recent lightning simulation experiments have not simulated the influence of blade rotation in the long term after corona inception. This study uses a finite element method and considers the adhesion and collision processes of positive ions, aerosol ions, and neutral particles to establish a two-dimensional positive corona discharge model based on a multicomponent diffusion transport equation. The microscopic distribution of these three types of particles and the influence mechanism of charged particles’ migration under electric fields and wind were studied. The results show that ion migration is affected by both electric field and wind speed. The higher the wind speed, the larger is the deviation amplitude of charged particles along the direction of wind. With an increase in wind speed, the corona current on the receptor surface gradually increases. When the wind speed is 30 m/s, the corona current peak value increases by almost six times when compared with that when no wind is present. From this, it can be inferred that blade rotation reduces the concentration of positive ion in the receptor area, thereby facilitating electron avalanche and streamer-leader conversion.

Study on Influence of Viaduct on Electric Field Distribution around High Speed Railway under Lightning Environment

Lightning damage is one of the key factors that affect secure and stable operation of high-speed railway. Research on the variation law of electric field intensity around high-speed railway under the effect of lightning downward leader is of great value to explain lightning-striking mechanism of high-speed railway. In this paper, a three-dimensional lightning simulation model for high-speed railway is established based on leader progression model, and the influence of different viaduct heights and materials on the electric field distribution around high-speed railway is simulated and analyzed. It is found that the electric field intensity of viaduct catenary system with rebar mesh material is greater than that with concrete material, besides, the height increment of viaduct would strengthen the electric field intensity of the catenary system. Therefore, the requirement on lightning protection designation and construction of high-speed railway in viaduct section should be higher than that in roadbed section.

The impact of lightning on tropospheric ozone chemistry using a new global lightning parametrisation

Abstract. A lightning parametrisation based on upward cloud ice flux is implemented in a chemistry–climate model (CCM) for the first time. The UK Chemistry and Aerosols model is used to study the impact of these lightning nitric oxide (NO) emissions on ozone. Comparisons are then made between the new ice flux parametrisation and the commonly used, cloud-top height parametrisation. The ice flux approach improves the simulation of lightning and the temporal correlations with ozone sonde measurements in the middle and upper troposphere. Peak values of ozone in these regions are attributed to high lightning NO emissions. The ice flux approach reduces the overestimation of tropical lightning apparent in this CCM when using the cloud-top approach. This results in less NO emission in the tropical upper troposphere and more in the extratropics when using the ice flux scheme. In the tropical upper troposphere the reduction in ozone concentration is around 5–10 %. Surprisingly, there is only a small reduction in tropospheric ozone burden when using the ice flux approach. The greatest absolute change in ozone burden is found in the lower stratosphere, suggesting that much of the ozone produced in the upper troposphere is transported to higher altitudes. Major differences in the frequency distribution of flash rates for the two approaches are found. The cloud-top height scheme has lower maximum flash rates and more mid-range flash rates than the ice flux scheme. The initial Ox (odd oxygen species) production associated with the frequency distribution of continental lightning is analysed to show that higher flash rates are less efficient at producing Ox; low flash rates initially produce around 10 times more Ox per flash than high-end flash rates. We find that the newly implemented lightning scheme performs favourably compared to the cloud-top scheme with respect to simulation of lightning and tropospheric ozone. This alternative lightning scheme shows spatial and temporal differences in ozone chemistry which may have implications for comparison between models and observations, as well as for simulation of future changes in tropospheric ozone.

Pulse generator with intermediate inductive storage as a lightning simulator.

Compact transportable generators are required for simulating a lightning current pulse for electrical apparatus testing. A bi-exponential current pulse has to be formed by such a generator (with a current rise time of about two orders of magnitude faster than the damping time). The objective of this study was to develop and investigate a compact pulse generator with intermediate inductive storage and a fuse opening switch as a simulator of lightning discharge. A Marx generator (six stages) with a capacitance of 1 μF and an output voltage of 240 kV was employed as primary storage. In each of the stages, two IK-50/3 (50 kV, 3 μF) capacitors are connected in parallel. The generator inductance is 2 μH. A test bed for the investigations was assembled with this generator. The generator operates without SF6 and without oil in atmospheric air, which is very important in practice. Straight copper wires with adjustable lengths and diameters were used for the electro-explosive opening switch. Tests were made with active-inductive loads (up to 0.1 Ω and up to 6.3 μH). The current rise time is lower than 1200 ns, and the damping time can be varied from 35 to 125 μs, following the definition of standard lightning current pulse in the IEC standard. Moreover, 1D MHD calculations of the fuse explosion were carried out self-consistently with the electric circuit equations, in order to calculate more accurately the load pulse parameters. The calculations agree fairly well with the tests. On the basis of the obtained results, the design of a transportable generator was developed for a lightning simulator with current of 50 kA and a pulse shape corresponding to the IEEE standard.

Estimation of transient surge energy transferred with associated time delays for individual components of surge protector circuits

Modern semiconductor technology is vulnerable to transient surges such as lightning. Transient voltage suppressor systems (TVSSs), which are installed to protect modern electronics, use non-linear components such as varistors and transient voltage suppressor diodes in their design. In the case of low-voltage (1000 V and less) AC power circuits, there is no clear approach to estimate the energy absorption and associated time delays in individual components in relation to the propagated transient surge. Numerical simulation techniques can be used to analyse the phenomenon of surge propagation within a TVSS and estimate the energy transferred to each component with associated time delays. Suitable mathematical models must be used for the non-linear components. This study presents the development of reasonably accurate models for the non-linear circuit elements and formulation of state equations for the TVSS, together with simulation results; results are experimentally validated using a lightning surge simulator. The method of analysing surge propagation presented here could be extended to analyse the phenomenon of surge propagation within power conversion stages which buffer the complex electronic circuits and the power source. The results discussed here indicate that the theoretical energy calculations are within 10% of the experimental results for the individual circuit elements.

FDTD simulation of direct lightning strike to a phase conductor: Influence of corona on transient voltages at the tower

In this paper, a simplified model of corona discharge for the finite-difference time-domain (FDTD) computations has been applied to analysis of transient voltages at the tower of a transmission line caused by direct lightning strikes to an upper phase conductor. In the simulations, three 40-m towers, separated by 300m, with one overhead ground wire and three phase conductors are employed. Corona is assumed to occur only on the upper phase conductor struck by lightning. The progression of corona streamers from the conductor is represented as the radial expansion of cylindrical conducting region around the conductor. The reduction of transient-voltage peak due to corona is not very significant, so that the voltage at the nearest tower exceeds the insulation level of 66/77kV power line considered in this paper. For a 10-kA peak current, the upper-phase-conductor voltage peaks are reduced by 26% and 21% for a positive stroke with 1-μs- and 3-μs-risetime currents, respectively, and those for negative-stroke case are reduced by 18% and 13%, respectively. For a 20-kA peak current, the corresponding upper-phase-voltage peaks are reduced by 32% and 25% for the positive-stroke case, and those for the negative-stroke case are reduced by 22% and 15%.

Lightning Protection Research and Simulation of High-Speed Railway Catenary

The existing high-speed railway in China is erected on the viaduct. The traction power supply system of high-speed railway consists of catenary with auto-transformer (AT). The catenary above the rails is supported by towers besides the rails. As the increase of the height from top of towers to ground, the probability of the pilot discharging of lightning to catenary will increase. And the pilot striking distance to ground always remains constant. So the horizons shielding effects for catenary will decrese, and the whole catenary naked in the atmosphere extremely easily struck by thunderbolt. In the important places, e.g., substation and areas of frequent lightning, the lightning arrester is installed to limit lightning overvoltage. But the lightning arrester can limit local overvoltage only. In fact, high-speed railway struck by lightning has affected the safety of power supply system in China. So more reasonable lightning protection measures for Chinas high-speed railway will be studied in this paper.

土壤电阻率对特高压输电线路塔顶电位的影响

本文建立了考虑电感效应和火花效应的等效接地体时变模型，搭建了特高压输电线路雷击仿真计算模型，来分析土壤电阻率对雷击特高压杆塔顶端时塔顶电位的影响规律。结果表明：当土壤电阻率较小时，塔顶电位随土壤电阻率增加而增加的速度较大，而当电阻率较大时，塔顶电位升高的比较平缓。应根据土壤电阻率情况做防雷设计。This paper established the equivalent model of the inductance effect and the spark effect of the grounding connector when attacked by lightning current. Meanwhile, the article explored the lightning simulation calculation model of the ultra-high voltage transmission lines, and analyzed the influence between the resistance rate and the tower potential when hit by lightning. The result indicates that: when the resistance rate of the soil is less, the tower potential increases greatly with the increase of the resistance rate; and when the resistance rate of the soil is bigger, it increases gently. So it is necessary to design the lightning protection based on the resistance rate of the soil.

Research of Lightning Over-Voltage and Simulation Program of Substation Based on EMTP

High voltage substation is the junction station of electrical power system. In order to conduct lightning over-voltage simulation and analysation of couple of substations rapidly and intuitively, a serialization supposed simulation program of substation is developed based on the research of EMTP kernel and data format. Model of impulse grounding resistance and improved leader progression is included in the program, which enhance the accuracy as much as possible and satisfying the demand for emulation of different type and voltage level. Through the simulation of some 500kV high voltage substation, the influence to lightning over-voltage of different system operating plan and lightning strike spots is analyzed, which verifies the validity and convenience of the program.

스마트기기 게임에 적합한 실시간 번개 시뮬레이션 연구

In this paper, we show a real-time lightning simulation for smart device game. Our proposed method uses physically based Dielectric Breakdown Model to similar real world lightning path and we simplify the algorithm for real-time simulation in smart device. In addition, the rendering process can render multiple lightning and can real-time render in smart device. Finally, our lightning can support interactive with user. The simulation method will be effectively useful for a game that needs a real-time simulation as its game element in smart device environment.