Direct Lightning Strikes Research Articles

Lightning Strike Danger Zone Detector System Integrated with Smartphone

The potential for direct hits and bounces from buildings during thunderstorms can endanger pedestrians in the open area of the Faculty of Engineering Untirta campus. So far, there has been no danger warning in the open area so that pedestrians in the area are not prepared if unwanted things happen, especially when there is rain and lightning. Direct lightning strikes are one of the hydrometeorological events that need to be watched out for. Because of its impact that can cause damage to objects and casualties if exposed to humans. The campus area has a fairly large open area, making the threat of lightning strikes can occur at any time, especially during the rainy season. The purpose of this research is to design and implement a direct lightning strike hazard zone detection device in the campus area of the Faculty of Engineering UNTIRTA located in the city of Cilegon. The stages of research carried out include analyzing the open area of the FT campus using the Rolling sphere method. After that, plotting the area of the analysis results. Then an area detection tool was created which is categorized as a direct lightning strike danger zone that is integrated with Smartphone notifications.

Lightning Injury: Case of a 7-Year-Old Child Struck by Lightning in Region 8 Guyana

Background: It is estimated that lightning occurrence frequency worldwide is 50 occurrences per second with 20% of those resulting in ground strikes. It is estimated that approximately 24,000 fatalities occur worldwide due to lightning strikes and in the US 25-50 patients die each year. The mechanisms of injury due to lightning strike are numerous which includes the effects of the electrical current passing through body tissue, burns and mechanical trauma. Cardiac and respiratory arrest are more common with direct lightning strikes and may lead to sudden death. Case Presentation: Here we present a case of child who was struck by lightning in a hinterland region. The child was found in an unconscious state by a passerby. He was then taken to a local health post where he regained consciousness. Initial vitals were stable, and child appeared to have suffered burns about the body. Arrangements were made and he was air dashed to GPHC. He was alert with stable vitals when he arrived, appeared to have suffered minor burns about the body. His ECG, X rays and CT head were all normal. He had an elevated CPK level which caused concern for Rhabdomyolysis. He was admitted to the paediatric ward. Outcome: The child spent 3 days on the ward, where he was monitored closely for any delayed complications related to lightning injuries. His CPK had normalized, he received dressings for his burns and was subsequently discharged home. Keywords: Lightning Strike, Lightening Injuries

Comparative Study and Investigation of Homogeneous Soil with Connected Circular and Cylindrical Electrodes Based on Fields Distribution of Direct Lightning Strike on Wind Turbine

Comparative Study and Investigation of Homogeneous Soil with Connected Circular and Cylindrical Electrodes Based on Fields Distribution of Direct Lightning Strike on Wind Turbine

Time domain modeling of lightning transients in grounding systems considering frequency dependence and soil ionization

This paper presents a new model for analyzing transient grounding system behavior during a direct lightning strike. The modeling that we propose allows us to consider a simple grounding conductor buried horizontally or vertically, a grounding grid, wind turbine grounding system and grounding circuits for wind farms while including the aerial parts (towers and blades). This modeling is developed directly in the time domain taking into account the frequency dependence of the impedance and admittance of the wired conductors and of the electrical parameters of the soil (ρ, ε) and also considering the ionization of the soil. This formalism is based on transmission line equations, rational approximation by vector fitting and the Finite Difference Time Domain numerical method. The proposed formalism is verified considering both simulations and experimental results from available published researches. The Ground Potential Rise GPR in the grounding circuits of wind farms are discussed during the first stroke and also during the subsequent stroke whose frequency range generates more propagation of electrical waves along conductors. This formalism makes it possible to contribute to all knowledge/research of grounding systems.

Identification of Lightning Strike Damage Severity Using Pulse Thermography Through Integration of Thermal Data

AbstractCarbon fibre reinforced polymers (CFRP) structures, e.g., wind turbine blades, are suspectable to direct lightning strikes due to their semiconductive nature and ability to conduct current. It is critical to identify and evaluate lightning damage as it can cause premature failure of the primary load carrying components. Direct strike lightning damage has been traditionally identified and assessed by ultrasonic (UT) inspection, which is time consuming, usually requires contact, and does not directly provide a measure of damage severity. An appealing alternative to UT is pulsed thermography (PT), which takes minutes to conduct rather than hours and does not require a couplant. The aim of this work is to explore the application of pulse thermography to identify and evaluate the damage state of CFRP panels damaged by simulated lightning strike. A new analysis technique is presented that provides a damage severity metric which allows damage to be categorized, separated, and quantified.

Improving lightning protection with corona minimising air terminals

A comprehensive approach to lightning protection is comprised of four key steps, namely protection against direct lightning strikes, dealing with surges and transients, dissipation of lightning currents via earthing and bonding, and protecting people. This paper deals with new research findings associated with direct-strike protection with lightning rods or “air terminals”, namely the effect of accumulated corona space charge around the tips of these components. There is now a great deal of consensus amongst lightning researchers and practitioners that space charge accumulation reduces the efficiency of an air terminal by inhibiting the initiation and development of an upward leader, a critical stage in the lightning attachment process. The paper describes measurements carried out in a high-voltage laboratory to quantify the amount of corona discharge that would be emitted under thunderstorm conditions from a variety of air terminals of different geometries. A unique, previously unreported aspect of these experiments was the corona testing of air terminals under dry and wet conditions. The results of these experiments showed that corona discharge (and hence space charge accumulation) from a standard Franklin rod is substantially higher than from the range of significantly blunter “corona minimising” air terminals that were tested. The previously reported polarity difference in corona characteristics was also observed, i.e., the magnitude of negative corona was larger than positive corona for the same ambient electric field. Differences in corona discharge were also observed under wet and dry conditions, where wet air terminals were found to produce modestly more corona. The paper then addresses the optimisation of air terminals, i.e., minimising corona discharge, for practical lightning protection applications, where the air terminal radius of curvature is tailored to its height and position of installation. Various researchers have made these calculations, the outcomes of which are summarised in this paper. In general, radii of curvature in the range 1–100 mm are required, depending on the installation height and location of the air terminal.

An experimental study on fire ignition in collector cable in wind power generation system caused by direct lightning strike

AbstractA separable connector is used for the power cables and apparatuses in renewable energy systems. The shield of the collector cable is sometimes an open circuit at one end to reduce power loss due to the shield current. However, this has a disadvantage from the viewpoint of lightning protection. The semiconductive part of the separable connector is grounded for safety. The ground potential rise due to a direct lightning strike to a wind tower sometimes damages the collector cables and power apparatuses in the wind tower. Combustion in a cable is one of the most serious types of lightning‐caused damage. This paper describes an experimental study on fire ignition in a collector cable caused by a ground potential rise due to a direct lightning strike to a receptor. The mechanism leading to fire ignition is discussed based on the experimental results. This paper also proposes a countermeasure against such fire ignition.

Rain may improve survival from direct lightning strikes to the human head

There is evidence that humans can survive a direct lightning strike to the head. Our question is: could water (rain) on the skin contribute to an increase in the survival rate? We measure the influence of rain during high-energy direct lightning strikes on a realistic three-compartment human head phantom. We find a lower number of perforations and eroded areas near the lightning strike impact points on the head phantom when rain was applied compared to no rain. Current amplitudes in the brain were lower with rain compared to no rain before a fully formed flashover. We conclude that rain on the scalp potentially contributes to the survival rate of 70–90% due to: (1) lower current exposition in the brain before a fully formed flashover, and (2) reduced mechanical and thermal damage.

TGFs, Gamma‐Ray Glows, and Direct Lightning Strike Radiation Observed During a Single Flight of a Balloon‐Borne Gamma‐Ray Spectrometer

AbstractTerrestrial gamma‐ray flashes (TGFs) and other high‐energy radiation phenomena related to thunderstorms remain incompletely understood since their discovery nearly 30 years ago. Space and ground‐based platforms have provided insights, but limitations exist in temporal resolution, signal‐to‐noise ratios, and proximity to events. This study presents findings from a balloon‐borne gamma‐ray spectrometer flown into a thunderstorm over northern Mississippi on 19 June 2023. The instrument detected three distinct millisecond‐duration TGF events correlated with lightning strikes. Sustained gamma‐ray glows lasting up to 2 minutes were measured and tied to thunderstorm electrostatic fields. Notably, radiation was observed during a direct lightning strike to the payload. This complex 800‐millisecond event reveals insights into radiation from leader propagation and return strokes. These findings from a single balloon flight demonstrate the prevalence of energetic processes within thunderstorms. Finally, the balloon platform offered an exceptional combination of temporal resolution and validation capabilities to advance the understanding of thunderstorm radiation motivating future follow‐up studies.

Flashover pattern analysis for 275 kV double circuit transmission lines during direct lightning strikes

Lightning overvoltage causes outages of transmission lines (TLs) in tropical countries. Identifying and analyzing the key factors responsible for tripping the lines can improve the performance of the lines. In this work, the flashover patterns due to direct lightning strikes on 275 kV double circuit TLs and towers in Malaysia was evaluated with Electromagnetic Transient Program (EMTP-RV). Three parameters that include lightning current magnitude, power frequency angle and tower footing resistance were analyzed on the line performance during direct lightning strikes. The simulated results found that two key parameters, lightning current at 270 kA and footing resistance at 50 Ω, reveal the highest impact on the insulator flashover. This finding was also verified from multivariate analysis results which is rarely found in the previous works in this field. As a key contribution in this work and in validation to the model, the simulated fault waveform patterns and voltage magnitudes were compared with the actual site data obtained from six different locations in Peninsular Malaysia. The analyzed results show a similar waveform pattern with an overall average voltage magnitude difference of 6.0 % before and after fault. The model is useful to electric utilities for analyzing transient performance of TLs.

Model and experimental verification of SOP transient in OPGW based on direct strike lightning.

We introduce inductive lightning and direct lightning that affect the state of polarization (SOP) of signal light in optical ground wire (OPGW) of power transmission line, deduce the helical component of direct lightning on OPGW, and establish the transient model of signal SOP in OPGW based on direct lightning. We also monitored actual optical transport network (OTN) systems deployed on OPGW in thunderstorm-prone areas for three months, recorded error codes and SOP transients of more than 1.5 Mrad/s using a bit error rate tester and a polarimeter accordingly. The highest SOP transient rate was up to 43 Mrad/s. Finally, we verify the accuracy of the model through simulation and experiment comparison.

Analyzing the Effect of Lightning Channel Impedance on the Lightning Overvoltages in Wind Turbines

Lightning is a natural phenomenon that can cause serious damage to power systems including wind farms. Wind Turbines (WTs) are tall structures and are often installed in areas with high lightning activity levels which makes them exposed to direct strikes. One of the parameters affecting the performance of the lightning protection system is the impedance of the lightning channel. In this paper, the effects of this impedance on the lightning overvoltages in wind turbines, and the energy absorbed by Surge Arresters (SAs), as the main lightning protection device, are investigated. The case study is carried out on a WT with 2 MVA of rated power where a direct lightning strike with a maximum current magnitude of 50 kA is struck to one of the WT's blades. Accurate models, designed for transient studies, are used for modeling different parts of the WT. The results of different scenarios are compared, and it is shown that as the value of lightning channel impedance gets higher, the overvoltage caused by the corresponding lightning strike, with the same current magnitude, increases too. In addition, it is shown that the higher the lightning channel impedance, the higher the absorbed energy by the arrester. This shows the importance of the lightning channel impedance's effect on high-voltage studies of WTs, as it can help in selecting proper lightning protection devices.

ВИЗНАЧЕННЯ ОПОРУ ЗАЗЕМЛЮВАЛЬНИХ ПРИСТРОЇВ ПІДСТАНЦІЙ 330(220) кВ

In the electric power industry of Ukraine, the main system-forming objects are power transmission lines and substations with 330(220) kV switchgear. The most powerful sources of danger at substations are short circuits on the busbars, a direct lightning strike or the operation of overvoltage limiters and arresters.The purpose of the article is to develop a method for determining the resistance of the grounding system of substations with open switchgear 330(220) kV, aimed at increasing accuracy, taking into account the most influential independent factors. The provisions of the theory of experiment planning, the theory of electric circuits, mathematical modeling in the package Grounding 1.0, LiGro and Microsoft Excel were used to conduct the research. In the paper, a comparative analysis of the known formulas for determining the resistance of the grounding system is carried out: the formula of the GOST 12.1.30-81 standard, Ohlendorf-Laurant, Laurent and Neumann, Schwartz, Sverak formulas, as well as the formula of the international standard IEEE Std 80-2013. The results of multifactorial experiments to determine the dependence of the resistance of the grounding system on its area, the size of the grid cell, the perimeter of the cross-section of the grounding, the equivalent specific resistance of the soil, the short-circuit current and the depth of the grid location are given. A graphical comparison of the results of determining the resistance according to the considered formulas was carried out. In the paper, the method of determining the parameters of grounding system of 330(220) kV substations was further developed, aimed at ensuring standardized values of the resistance of the grounding system and the ground potential rise using formulas obtained from the results of multifactorial experiments. The results obtained in the work will make it possible to reduce the probability of damage to the insulation of 6-10 kV cables, as well as cables of secondary circuits from low-frequency and high-frequency (pulse) voltages when large currents flow into the grounding system in the mode of a single-phase short-circuit to the ground in electrical grid with a grounded neutral. References 9, tables 2, figures 6.

A protocol for selecting viable transmission line arrester for optimal lightning protection

Direct lightning strikes on overhead lines and towers causes power system outages. Optimal surge arrester placement is a practical and economical protection technique. From research trends, three types of transmission line arresters are in practice: Non-Gapped Line Arrester (NGLA), Externally Gapped Line Arrester (EGLA) and Multi Chamber Insulator Arrester (MCIA). This study proposed a simplified guide for selecting the most suitable line arrester considering the placement configurations, double circuit outage prevention and energy capabilities. Electromagnetic Transient Program was implemented to analyze back flashover performance of a typical 275 kV double circuit transmission line in Malaysia. Critical flashover parameters considered are lightning current magnitude, tower footing resistance, and power frequency angle. Analyzed results from the three arresters found that installing four arresters, two per circuit, at the lower and upper phases respectively, is the most optimal and universal double outage mitigation technique. Energy comparison reveals that MCIA discharges 54% and 44% less energy than NGLA and EGLA respectively. Also, from 132 kV system results, MCIA discharges 74% and 22% lesser energy respectively. From further validation of the simulation model, NGLA discharged 23.8% more energy than EGLA from experimental results. The proposed guide is applicable to double circuit lines below 275 kV.

Analysis of Transient in Secondary Cable Due to a Direct Lightning Strike on Grounding Grid

When a substation suffers from a lightning strike, beside the interference from the space, there are two main ways in which the transient disturbance affects the secondary cable through the grounding system: the uneven potential distribution and the mutual inductance between the secondary cable and the ground conductor. In this article, a circuit model of grounding grid is developed taking into consideration the mutual inductance between the secondary cable and the ground conductor. While a circuit model of the secondary cable is established with the consideration of uneven ground potential distribution and the mutual inductance between the secondary cable and the ground conductor. Then, the two models are unified to calculate the transient disturbance in the secondary cable due to a lightning strike on the grounding grid. The feasibility of the method is verified through experiments. Then, the effect of the ground potential difference of the grounding grid and its mutual induction with the cable is analyzed. The results show that both the mutual inductance between the cable and the grid and the uneven ground potential distribution greatly affect the transient disturbance in secondary cable.

Evaluation of lightning-originated stress on distribution class surge arresters

The paper focuses on evaluating the stress on distribution class surge arresters (SAs) caused by lightning strikes. It proposes a procedure for estimating the statistical distribution of energy absorbed by SAs due to both indirect and direct lightning strikes, which is a crucial step for assessing the probability of SAs failure. Two different SA representations are considered, namely, a static nonlinear resistance and a dynamic, frequency dependent model. After analyzing the overvoltage and current waveforms caused by lightning strikes and considering the effect of flashover occurrence, the paper assesses the effect of several factors on the current and energy absorption, namely the presence of a periodically grounded shield wire, of the grounding resistance value, and of the distance between subsequent SAs. The analysis shows that the static model can be considered accurate enough for evaluating the stress originated by direct and indirect lightning on distribution class SAs.

EFFECT OF DISCHARGE CURRENT MAGNITUDE ON EFFECTIVENESS OF OVERHEAD POWER LINE PROTECTION AGAINST DIRECT LIGHTNING STROKES

In this paper the efficiency of lightning shielding provided by single overhead ground wire mounted atop of a double circuit self-supported 220 kV lattice power transmission line tower with a total height of 37.115 m was examined. According to the electro-geometric concept, each phase conductor of a power transmission line has an area where the overhead ground wire does not provide full protection against a direct lightning strike. The width of this unprotected area depends on the design and dimensions of overhead power line tower, the expected magnitude of the lightning current and decreases with increasing magnitude of the discharge current. The lightning protection effectiveness of upper and middle phase conductors was studied. The values of the minimum lightning current, capable of causing an insulation flashover in case of the lightning shielding failure were calculated. The minimum values ​​of the lightning current at which complete shielding is achieved have also been determined. It was found that for upper phase conductor the minimum current at which a complete lightning shielding is achieved is 7.597 kA, and it is smaller than minimum current of 8.604 kA capable to cause an electrical flashover of the transmission line insulation. For middle phase conductor the lowest current at which a complete lightning shielding is achieved is 5.976 kA, that is much smaller than minimum current of 9.206 kA leading to an insulation flashover. The results show that the specified overhead power line is protected from dangerous lightning currents. However, computations show that downward lightning flashes having a smaller current magnitude are able to bypass the shield wire and hit the phase conductors. In this regard, due to unpredictable nature of lightning, to improve the lightning protection of power lines, other measures can be applied, including the use transmission line arresters mounted on or near towers at individual points of the power line. When thunderstorm activity increases due to global warming, strengthening of lightning protection measures is justified.

Transient modeling of photovoltaic system (PV) to investigating the peak of transient voltage generated by direct and indirect lightning strikes

Transient modeling of photovoltaic system (PV) to investigating the peak of transient voltage generated by direct and indirect lightning strikes

がいしの塩汚損が配電線直撃雷によるスパークオーバ発生率に与える影響

To improve the lightning-outage-rate calculation method of medium-voltage distribution lines, it is important to accurately assess sparkover rates of insulators. In salt polluted areas, lightning outage rates may increase due to the deterioration of insulation performance of insulators. Although the sparkover characteristics of salt-polluted insulators against the standard lightning impulse voltage have been reported in previous works, the sparkover characteristics against short-wave-tail lightning impulse voltages, which occur across insulators on distribution lines by direct lightning strikes, still remain not clarified.

Rogowski Coil Sensors for Measuring Lightning Strike Currents on Mechanical Aircraft Joints

The study of currents flowing through the fuselage of an airplane is of vital importance from the standpoint of electromagnetic compatibility due to their potential for causing severe failures on embedded systems. Direct lightning strikes can produce extremely high currents propagating through the fuselage panels. Such high currents are critical when flowing through mechanical joints, a point of complex analysis due to the existing electrical discontinuities. Consequently, understanding the propagation of these currents is vital for protecting avionics through improved joints not only from a structural standpoint, but also from an electromagnetic perspective. In this article, we propose designing and validating a Rogowski coil sensor to measure the current flux through the mechanical joints that attach different fuselage panels. This sensor is theoretically analyzed, and a circuit model is provided. Then, a printed circuit board (PCB) Rogowski coil is designed and manufactured for measuring high-intensity pulsed currents with a bandwidth of 10 MHz. Subsequently, the probe is characterized through its S-parameters. Next, its equivalent lumped-element circuit is extracted and simulated for validating the sensor’s transient response. Finally, the Rogowski coil sensor is experimentally evaluated in the measurement of a surge current pulse that emulates a real scenario.