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Lightning is an electrical discharge phenomenon in the atmosphere caused by charge separation in clouds, which is divided into cloud-to-ground (CG) and cloud-to-cloud (CC) lightning. In recent years, research on the characteristics of multiple-stroke ground lightning and the amplitude of lightning currents has attracted significant attention. The amplitude of lightning currents serves as fundamental data for lightning protection in power systems. Its accurate measurement is crucial for designing and safeguarding power systems. This paper obtains data from a lightning location system and analyzes the probability density distribution of lightning current amplitudes. It is found that the median of lightning currents gradually decreases with an increasing number of multiple strokes, and there is a trend in the change of lightning current steepness. As the number of strokes increases, the median value of amplitude distribution gradually decreases, while the steepness coefficient shows an increasing trend. These research findings contribute to a deeper understanding of the characteristics of lightning and provide important references for lightning prevention and disaster reduction. [ABSTRACT FROM AUTHOR]

In this study, we used the three-dimensional (3D) printing method to design and fabricate a radar-absorbing structure (RAS) to protect against damage caused by lightning strikes. A carbon black-dispersed 3D filament was used as reinforcement in the composite, and metalized fibers served as the feedstock for 3D-printing. The return losses measured in the X-band and Ku-band (8.2–18 GHz) indicated a maximum return loss of −28.98 dB at 10.68 GHz, with a broad bandwidth of 6.56 GHz in the frequency range of 8.2-18 GHz. A coupled electrical–thermal analysis confirmed that the proposed carbon black-dispersed filament provided conductive paths, which contributed to direct current, energy dissipation, and lightning strike protection. The 3D-printing method ensured a sufficient level of electrical conductivity, limiting the area and depth of damage caused by lightning strikes. Therefore, 3D-printed-RASs, reinforced by electrically conductive materials, can effectively protect against lightning strikes. [ABSTRACT FROM AUTHOR]

High-voltage direct current (HVDC) transmission lines are increasing in number and overall length. This means their lightning protection must be of higher importance as well. Probability-modulated attractive space (PMAS) theory is a proven geometry-based method for lightning protection calculations. However, it cannot accurately assess the number and parameters of direct lightning strikes to the phase conductor of HVDC lines, because the effect of pole voltage on lightning attachment cannot be considered. This effect can be taken into account with leader progression models, which feature lightning physics models that can quantify the effect of the electric field around the phase conductor, which can be quite complex compared to geometric models in general. In this paper, a novel method, called the attractive space matrix, is presented to examine the effect of the DC electric field around the conductor on the attractive space. The algorithm is based on the physical background of the self-consistent leader inception and propagation model. The results could lead to improved lightning protection of HVDC lines and reduce the outages caused by direct lightning strikes. [ABSTRACT FROM AUTHOR]

Positive lightning leaders are a ubiquitous, yet poorly understood, component of lightning flashes. Upward lightning started by positive leaders may be formed when nearby storm activity induces electrical charges in a tall structure, such as communications towers or wind turbines. Alternatively, upward lightning can be triggered with the rocket‐and‐wire technique. In this paper, we introduce a new self‐consistent model for this important discharge mode, one which solves Maxwell's equations under the quasi‐electrostatic approximation. The model also includes a realistic treatment of the nonlinear plasma conductivity within the leader channel. This new computational tool explains the origin of the positive leader speed, of ∼ ${\sim} $10s of km/s, as well as why it displays a steady behavior over time. The model also explains the temporal evolution of current to ground measured during the early stages of rocket‐triggered lightning, where the current exhibits a series of small‐amplitude pulses, which disappear over time. The article also outlines straightforward criteria for leader inception, which may have practical applications for lightning protection. Plain Language Summary: Lightning which propagates upward from the ground to the cloud has been the subject of intense investigation in recent years. Upward lightning may be formed when nearby storm activity induces electrical charges in a tall structure, such as communications towers or wind turbines. Alternatively, upward lightning can be triggered with the rocket‐and‐wire technique, as routinely performed at New Mexico Tech's Langmuir Lab. The latter presents a great opportunity for studying the physics of lightning and its impacts. In this paper, we introduce a new self‐consistent model for the initial stages of upward lightning, one rooted in basic physics laws, which describes the leader propagation as a series of small steps. The calculations explain the behavior of leader speed and current transferred to ground. A better understanding of upward lightning and its initiation and propagation could be used to better protect structures such as communication towers, tall buildings, wind turbines, or other tall structures which are prone to damage from lightning strikes. Key Points: New self‐consistent leader model predicts experimentally measured leader speeds and propagation behaviorModel postulates leader propagation in small steps and explains behavior of current measured to ground, including presence of pulsesCriteria for upward leader ignition is strictly defined based on wire height and ambient electric field [ABSTRACT FROM AUTHOR]

In recent years, lightning protection cables with integrated optical module are used fairly extensively. These cables actually have the form of a cable made of several layers of steel wires with corrosion-resistant coating and a tubular case made either of aluminum or of stainless steel (central or in a whip) filled with a hydrophobic gel and optical fibers. Circular plastic compression in the process of production of lightning protection cable with integrated optical module enables us to improve the electric contacts of wires in and between the layers and increase both the resistance to the lightning discharge impulse and mechanical strength. For the incorrectly chosen geometric parameters of wires in the first and second layers, circular plastic compression may lead to a significant deformation of the optical module and, as a result, to the unacceptable elevation of the coefficient of attenuation of the transmitted signal. By the method of computer simulation, we determine the value of guaranteed gap between the inner layer of the lightning protection cable with integrated optical module and the central tube guaranteeing the decrease in the level of deformation of the outer shell of the optical module down to admissible values. The possibility of formation of lateral contacts between the wires of the first layer contributing to a decrease in the radial component of pressure transmitted to the surface of the module is demonstrated for the optimized design of the cable. The accumulated results of computer simulation can be used for the optimization of the design and geometric parameters and the level of strand compression required to minimize the deformation of the outer shell of central tube of the integrated optical module of the lightning protection cable. [ABSTRACT FROM AUTHOR]

Grid-integrated photovoltaic (PV) systems are currently undergoing explosive growth in Malaysia. However, as more PV systems are installed close to transmission lines, there are concerns about the impact of electromagnetic (EM) properties affecting the performance and operation of the PV systems if they are exposed to lightning strikes, particularly indirect ones. Therefore, this study aims to model the impact of indirect lightning strikes on PV systems installed in proximity to transmission lines. The model involves developing a 3D model of the PV system together with a sample transmission line and creating an artificial lightning event to study the EM activity within the area. The results are compared to the IEC 61000 standard to determine its level of r\hazard. From the simulation results, it was found that the current intensity, H, of the disturbance, can reach up to 63% more than the standard limit stipulated in the standards. The significance of the study ensures that PV systems installed within the vicinity of power lines or substations have adequate lightning protection systems (LPS) as well as proper earthing systems. [ABSTRACT FROM AUTHOR]

Climate change effects influence the sustainability of wind and photovoltaic energies as renewable sources. Similarly, infrastructure for renewable energy is structurally vulnerable to lightning strikes. Hence, a system for detecting and monitoring lightning activity is necessary to predict and adapt to climate change trends and to enhance the lightning protection system's capability. One such system for observing and locating lightning is very high frequency (VHF) interferometry. Various factors, such as the baseline distance between sensors, the frequencies used, and the quality of the analyzed signal, will influence the system's accuracy. This paper discusses these factors through an extensive literature review. This study aims to identify the factor that most significantly affects the system's accuracy and to determine the technical adjustments required to improve this accuracy. Enhanced precision in the interferometry system will provide a more detailed view of lightning activity, thereby aiding in the climate change prediction that could impact electricity generation from renewable sources. Accurate lightning location detection can also serve as a basis for designing effective lightning protection systems for renewable energy infrastructure. [ABSTRACT FROM AUTHOR]

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Abstract Conventional approaches for determining the optimal locations of surge arresters (SAs) can result in an unnecessary increase in the number of these devices in high‐voltage substations. This study presents an effective technique for determining the optimal locations of SAs. The lightning back flashover (BF) and switching over‐voltages are predicted with the accurate modeling of the transient behavior of all elements of high‐voltage substations and transmission lines, considering the effect of environmental conditions. Also, the proposed limiting parameter Monte Carlo (MC‐LP) method is utilized to correctly select the probability distribution of the possible strokes for predicting the insulation risk (IR) of a transformer based on transient over‐voltage on the transformer end. Therefore, the most appropriate location to install an SA can be determined with a minimum number of calculations using the structural data of the substation, lines connected to it, and the transformer. Simulations are based on experimental results, and the number of calculations significantly decreases using the proposed algorithm. Simulations of the sample network and implementation of the proposed algorithm with MATLAB and EMTP‐RV prove the efficiency of the proposed method for optimum SA placement.

This paper describes an efficient approach to the broadband analysis of lightning protection systems (LPSs) using the method of moments (MoM) implemented in the frequency domain. The adaptive frequency sampling (AFS) algorithm, based on a rational interpolation of the relevant observable (e.g., voltage, current, electric or magnetic field) which describes the properties of the LPS, is employed to reduce the number of samples computed by the full-wave MoM. This improvement is achieved by the quick comparison of two interpolants with the use of the Stöer–Bulirsch algorithm, which provides the frequency location of the next MoM samples for computations. This algorithm allows for the efficient localization of resonant frequencies while reducing the number of samples computed over the entire frequency range. In the instances when the induced noise is determined in low-voltage installations protected by various types of LPSs, reductions in computational overhead equal to 47.9× and 72.1× in broadband LPS simulations are obtained. Hence, the proposed approach allows for a significant reduction in computational overhead in comparison to standard, uniformly sampled simulations. [ABSTRACT FROM AUTHOR]

Lightning protection of large‐scale photovoltaic power stations and grid‐connected lines has gradually become a difficult problem with more and more large‐scale photovoltaic power stations connected to the State Grid. In order to enable large photovoltaic power station to continue and stably operate, this paper targeted the grid‐connected transmission line and designed the spiral multi‐pair blowing device. The device leads the plasma arc to take on a spiral path, and the energy of plasma arc is sprayed out at the convection fracture of the unit and continuously consumed. Experiment results show that the device can extinguish lightning current in 2.1 ms and restore the transmission voltage to the normal level. The lightning protection device has the effectiveness of arc extinguishing, and it is beneficial to reduce lightning trip rate of transmission line of large‐scale photovoltaic power stations. © 2024 Institute of Electrical Engineers of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

AbstractThe copper mesh provides effective lightning strike protection for composite structures, while its efficiency can be compromised in scarf-repaired composite structures. In this study, after verified by test results, a numerical analysis procedure was employed to predict the lightning ablation damage and residual bending performances of scarf-repaired composite laminates with copper mesh protection. Initially, the ablation damage and bending damage mechanisms of good repaired and poor repaired composite laminates were analyzed. Then, the impact of lightning strike attachment position and repair design parameters including overlap length and thickness of adhesive layer on the lighting protection performances was investigated. The results indicate that ablation damage of composite and adhesive materials near the repair area significantly compromises structural integrity and reduces the bending strength. The predominant bending failure mode of scarf-repaired woven composite laminates after lightning strike is fiber failure in warp direction, accompanied by small areas of matrix failure and delamination failure. The reestablishment level of the electrical path varies with overlap length and thickness of adhesive layer, subsequently affecting the ablation damage area and depth. This study can provide a reference for the design and process control of scarf-repair in copper mesh protected composite structures. [ABSTRACT FROM AUTHOR]

Copyright of Przegląd Elektrotechniczny is the property of Przeglad Elektrotechniczny and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Conventional approaches for determining the optimal locations of surge arresters (SAs) can result in an unnecessary increase in the number of these devices in high‐voltage substations. This study presents an effective technique for determining the optimal locations of SAs. The lightning back flashover (BF) and switching over‐voltages are predicted with the accurate modeling of the transient behavior of all elements of high‐voltage substations and transmission lines, considering the effect of environmental conditions. Also, the proposed limiting parameter Monte Carlo (MC‐LP) method is utilized to correctly select the probability distribution of the possible strokes for predicting the insulation risk (IR) of a transformer based on transient over‐voltage on the transformer end. Therefore, the most appropriate location to install an SA can be determined with a minimum number of calculations using the structural data of the substation, lines connected to it, and the transformer. Simulations are based on experimental results, and the number of calculations significantly decreases using the proposed algorithm. Simulations of the sample network and implementation of the proposed algorithm with MATLAB and EMTP‐RV prove the efficiency of the proposed method for optimum SA placement. [ABSTRACT FROM AUTHOR]

The increasing deployment of wind turbines in technologically advanced nations underscores the need to enhance their reliability, extend their operational lifespan, and minimize failures. The current protection devices for wind turbine components do not sufficiently shield them from various external factors that degrade performance. This study addresses the environmental and technical challenges that disrupt wind turbine operations and reviews existing research and technical solutions for protecting individual components, supported by experimental findings. Using a decomposition method followed by the integration of protection components, we propose a combined protection system designed to improve the overall resilience of wind turbines. The proposed system aims to reduce incidents, extend service life, and increase reliability, addressing a critical gap in wind energy technology and contributing to its continued development and efficiency. [ABSTRACT FROM AUTHOR]

In the past, lightning strike risk assessment of buildings mainly referred to the Protection against Lightning--Part 2% Risk Management (IEC 62305-2-2010) based on protection angle method. Lightning strike risk assessment of wind farms was conducted according to the Lightning Protection for Wind Energy System (IEC 61400-24-2019), which proposed the method of lightning strike risk assessment for wind turbine. In fact, the basic idea of the two is the same, that is, the source of the lightning strike wind turbine is transformed from the former S1 - S4 to the latter ND - NDJ. According to the above method, wind farm was evaluated, and it has been proved that the practice can not achieve good results. After 2018, China has issued the Guide to Evaluation of Lightning Protection Technology in Buildings (T/GZLY 3 - 2022) and the Technical Specifications for Lightning Interception in Forest Areas (T/LYCY 4062 - 2024) based on semicircle protection, in which the source of risk defined by lightning point was closer to the reality, highly targeted and effective. Taking offshore wind farm as an example, this paper introduced a new method of establishing six evaluation indicators to determine the risk level according to the principle of compliance and the new protection technology of semi-circular method, which can be used as a reference for technical personnel. [ABSTRACT FROM AUTHOR]

Lightning strikes on aircraft are mainly due to self-triggered bidirectional leader discharges. Understanding the physical processes of lightning strikes is the basis for designing appropriate lightning protection measures. For this purpose, the development processes of bidirectional leaders triggered by a floating conductor were studied in a laboratory. In this paper, an experimental platform for the observation of bidirectional leader discharges is established through a reasonable gap arrangement. The discharge processes were recorded by a high-speed camera with up to 504 000 f/s. The effects of negative streamer discharges on the positive leader propagation speed as well as brightness during the bidirectional leader discharge at different electric field rise rates were mainly studied and quantitatively analyzed by introducing incremental coefficients. The experimental results show that the discharge development at the negative end of the floating conductor lags behind that at the positive end, and there is a coupling phenomenon between the positive and the negative discharge. At low electric field rise rates, when a negative streamer discharge occurs, it causes a positive corona burst, resulting in a sharp increase in brightness, while on the contrary the leader speed change is not as pronounced as the brightness change. As the rate of rise of the electric field increases, the effect of the discharge at the negative end on the positive end gradually decreases. This work could provide a theoretical basis for understanding the physical process of lightning strikes on aircraft. [ABSTRACT FROM AUTHOR]

Flow ultrasound generators are devices that emit high-frequency sound waves due to the hydrodynamic instability of the supersonic flow. In the electric power industry, such generators are used in arc quenching systems of high-voltage gas blast circuit breakers. The design of the flow ultrasound generator includes a nozzle and a hollow cylindrical resonator. Self-oscillations of the sealing waves occur when a supersonic gas jet collides with a resonator. This article is devoted to the analysis of the arrester operation, which has design features of flow ultrasound generators. The paper includes both experimental investigations of the proposed spark gap arrester design and mathematical modeling of the processes occurring in it. A description of the methods used is presented, and a comparison of the time dependences of currents and voltages obtained as a result of experimental studies and as a result of calculations is performed in the next section. The calculation results include oscillograms of the voltage and current, and the plasma temperature distribution in the arrester chamber at different moments of time. The investigations show that the presence of a nozzle and resonator leads to an intensification of the gas dynamic effect on the electric arc. [ABSTRACT FROM AUTHOR]

The protection system of an electrical equipment is very important because it ensures its proper and continuous functioning. The overvoltages protection is a part of the protection system, particularly very important. This study highlights a number of methods, which can be applied to protect the electrical circuits in case of the occurrence ofovervoltages. Overvoltages caused by lightning strikes can lead to major faults that can appear in electrical circuits or can completely damage them. The paper also presents the combined methods of protection from overvoltages due to the unwanted overvoltages due to lightning strikes, applicable for all types of the electrical equipments with details and arguments for each method used. It also presents the methods of testing surge arresters/varistors with metal oxides, the measurement schemes together with the devices used and the results obtained. It is highlighted by electrical measurements the response time of varistors to transient conditions, that has a significantly impact of the effectiveness surge protection. [ABSTRACT FROM AUTHOR]

The upward discharge is a significant factor threatening the operation of wind farms. This paper investigates the inception and development of upward leaders of wind turbines' tip, where blade rotation prevents charge accumulation, using charge density models from laboratory discharges and artificially triggered lightning. The results indicate that larger return stroke currents create higher spatial potentials, and slower downward leader speeds allow for longer development time, favoring the development of upward leaders. As wind turbine sizes increase, the rotation of the blade tips resembles artificially triggered lightning, and the long air gap discharge model may underestimate the development of upward leaders. Calculations from the artificially triggered lightning model reveal improved upward leader formation when further laterally away from the downward leader within a certain distance, elucidating why multiple upward leaders are frequently observed around turbines. The striking distance and attractive radius are largely determined by the development of upward leaders. The absence of corona charge shielding at blade tips means upward leader inception is independent of downward leader velocity, emphasizing downward leaders' significant influence on turbines. Thus, the formula for estimating a wind turbine's lightning incidence requires integrating the return stroke current and velocity of the downward leader. [ABSTRACT FROM AUTHOR]

Lightning is the severest threaten to safe operation of wind turbines. In this letter, the authors present the first altitude‐triggered lightning experiment involving an elevated 12 m‐long wind turbine blade placed on the ground. A total of 50 precursors with amplitude over 62.9 A were observed through measurements of channel‐base current, fast electric field, and optical data. The air gap with around 3–5 m has been bridged between the wire's lower extremity and the metal blade tip during ascending of the rocket and it is observed to be luminous by slow framing rate camera. The precursors are classified into three groups, namely bipolar pulses, unipolar pulses, and group pulses. Excluding the precursors preceding the initial stage and M‐components at the late‐time of the initial stage, five stages are classified. In the first stage, the current remains limited at a relatively small value, while the electric field exhibited a slow rising behavior with positive polarity. In the second stage, the current starts to increase, and the electric field rapidly intensifies due to the accumulating charge, and the wire is assumed to experience an explosion. In the third stage, the reconnection process occurs. The current is characterized by a peak value of 1.45 kA with 10%–90% risetime of 10.4 μs. The electric fields suffer from notable decrease and are characterized by a microsecond‐scale V‐shape pulse. The current cutoff is quite short that almost not found. In the fourth step, the current is characterized by superimposed pulses. The final stage is the channel darkening. Plain Language Summary: Observation results are reported in detail about the altitude‐triggered lightning experiment involving an elevated 12 m‐long wind turbine blade placed on the ground. There are fruitful precursors prior to the beginning of the initial stage. The precursors demonstrate that the air gap with around 3–5 m has been bridged between the wire and the metal blade tip. The precursors are grouped into three groups, namely bipolar pulses, unipolar pulses, and group pulses. The initial stage is classified into five periods. The triggering wire is believed to be vapourized during the second stage. The so‐called initial current variation (ICV), also called reconnection process, occurs at the third stage. The superimposed pulses are found immediately after the reconnection process in the fourth stage. The late‐time of the initial stage is also characterized by superimposed pulses associated with M‐components. This work is potentially helpful to understand the physical process lightning strikes a wind turbine, and design lightning protection strategies for wind turbines. Key Points: First altitude‐triggered lightning experiment associated with an elevated 12 m‐long wind turbine blade has been conducted through simultaneous measurements of current, electric fields and optical dataThe 50 precursors over 62.9 A proceeding the initial stage are classified into three groups: (a) bipolar pulses with the notably initial positive peak and followed by the negative excursion; (b) unipolar pulses with the notably initial positive peak but with quite flat late‐time response; and (c) group pulsesFive stages associated with channel reestablishment are classified according to the measured current and electric field, in which the current cutoff is quite short that almost not found [ABSTRACT FROM AUTHOR]

Lightning protection near the fan is the key point of lightning protection in wind farm, which affects the safe and effective delivery of wind power resources. At present, the three-phase multi-gap arrester installed on a base tower behind the collector can cooperate with the zinc oxide arrester to reduce the system failure caused by the arrester failure. However, the chopped wave generated by the multi-gap arrester when it acts is transmitted to the fan box transformer along the line, which may threaten the insulation of the transformer winding. Based on the above problems, this paper builds a simulation model on ATP to analyze the impact of wave clipping of multi-gap arrester on the insulation of fan transformer windings, considers the conventional installation mode and the limit installation mode of multi-gap arrester, and calculates that the wave clipping overvoltage generated by multi-gap arrester after being struck by lightning in two cases is the impact on the insulation of fan transformer. Through the simulation analysis, it is found that the higher the amplitude of the lightning current, the larger the amplitude of the overvoltage generated by the truncated wave, the steeper the wave head, and the greater the threat to the insulation of the fan box. The damage degree of round lightning is less than that of counter lightning. When a multi-gap arrester is installed in a collector tower, the 100 kA lightning current may destroy the insulation of the fan box transformer winding and require additional protective measures. It is recommended that the multi-gap arrester be installed from the next pole tower of the collector tower in the wind farm. [ABSTRACT FROM AUTHOR]

This paper proposes an Artificial Neural Network (ANN) model using a Multi-Stage method to optimize the configuration of an External Lightning Protection System (ELPS) and grounding system. ELPS is a system designed to protect an area from damage caused by lightning strikes. Meanwhile, the grounding system functions to direct excess electric current from lightning strikes into the ground. This study identifies the optimal protection system configuration, reducing the need for excessive components. The ELPS configuration includes the number of protection pole units and the height of the protection poles. In contrast, the grounding system configuration consists of the number of electrode units and the length of the electrodes. This study focuses on the protection system configuration at a Photovoltaic Power Station, where the area is highly vulnerable to lightning strikes. Several aspects need to be considered in determining the appropriate configuration, such as average thunderstorm days per year, ELPS efficiency, total area of photovoltaic module, area to be protected, soil resistivity, electrode spacing factor, and the total required electrode resistance. The proposed multi-stage ANN model consists of three processing stages, each responsible for handling a portion of the overall system tasks. The first stage is responsible for determining the protection pole configuration. In the second stage, the Lightning Protection Level (LPL) classification is performed. Then, in the third stage, the process of determining the grounding configuration is handled. The analysis results show that the Multi-Stage ANN model can effectively determine the configuration with a low error rate: MAE of 0.265, RMSE of 0.314, and MPE of 9.533%. This model can also explain data variation well, as indicated by the high R 2 value of 0.961. The comparison results conducted with ATP/EMTP software show that the configuration produced by ANN results in fewer protection pole units but with greater height. Meanwhile, ANN produces a configuration with shorter electrode lengths but fewer units in the grounding system. [ABSTRACT FROM AUTHOR]

Distribution lines are an important component of a power system. Lightning disasters have serious adverse effects on the reliability of the power supply in distribution networks. In response to the current lack of research on lightning protection in distribution networks under continuous lightning strikes, we built a transient simulation model and calculated the lightning withstanding level and lightning outage rate of distribution lines under continuous lightning strikes. In addition, the impact of different factors on the lightning withstanding level and lightning outage rate of distribution lines under continuous lightning strikes was calculated for different lightning protection strategies. Finally, differentiated lightning protection strategies based on the lightning outage rate calculation were proposed. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Polytechnic is the property of Journal of Polytechnic and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The impact of the topological formation of wind farms upon the lightning induced overvoltages injected into the grid was not covered earlier in literature. However, this topic is highly important to be investigated to allow the usage of the most reliable topology against lightning strikes. For such reason, the paper investigates this point with consideration of most damaging cases as lightning strikes to multi-blades. The testing used ATP software for four main topologies, radial, single-sided ring SSR, double sided ring and star topology. The features defining the similarities in response and the variance range between these topologies were recorded and analyzed. The multi-blade strikes gave an expected increase of 15% to 100% in the injected overvoltage to the grid for all topologies. The star topology showed the most reliable performance by allowing the least injected overvoltage to the grid. The percentage of reduction in the magnitude of the injected overvoltages reached 50.78%, 66.07% and 89.04% for SSR, DSR and star topology respectively with respect to radial topology. Recommendation was provided for design engineers to consider star topology during design phase in terms of more reliable lightning protection. [ABSTRACT FROM AUTHOR]

Copyright of Przegląd Elektrotechniczny is the property of Przeglad Elektrotechniczny and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The reliability and safety of large-scale solar photovoltaic systems (LSSPV) is paramount in harnessing renewable energy sources effectively. Given the increasing adoption of solar energy in Malaysian regions prone to lightning strikes, understanding and enhancing protection mechanisms is imperative. This study investigated an induced current protection system for LSSPV using an early streamer emission (ESE) air terminal in Malaysia. Two systems (ESE and Franklin lightning rod types) were employed in a 50 MWp PV power plant spanning 260 acres and were installed on the lightning arrester to ensure adequate protection. The Franklin rod type comprised 763 pieces and was constructed following the Council of Engineer standards (Thailand) standard. Meanwhile, the ESE lightning rod contained 68 pieces and was built following the NFC17102 standard (France). A 150 kA direct lightning impact was then simulated on the PV power plant using MATLAB/Simulink. Consequently, the ESE lightning protection system (LPS) effectively protected and prevented the lightning strike. The Franklin rod type's shading effects and installation costs (USD 10,026,800 vs. USD 8,026,800) were also more significant than the ESE rod type. These outcomes demonstrated that the ESE LPS was suitable for the PV power plant implementation. The findings of this study could also assist in optimizing the lightning protection technology for large-scale PV power plants. ABSTRAK: Kebolehpercayaan dan keselamatan sistem fotovoltan suria berskala besar (LSSPV) adalah penting dalam memanfaatkan sumber tenaga boleh diperbaharui dengan berkesan. Memandangkan penggunaan tenaga suria yang semakin meningkat di kawasan Malaysia yang terdedah kepada panahan kilat, pemahaman dan meningkatkan mekanisme perlindungan adalah penting. Kajian ini menyiasat sistem perlindungan arus teraruh untuk LSSPV menggunakan terminal udara pelepasan aliran awal (ESE) di Malaysia. Dua sistem (jenis rod kilat ESE dan rod Franklin) telah digunakan dalam loji kuasa PV 50 MWp seluas 260 ekar dan dipasang pada penangkap kilat untuk memastikan perlindungan yang mencukupi. Jenis rod Franklin terdiri daripada 763 keping dan dibina mengikut piawaian Majlis Jurutera (Thailand). Sementara itu, rod kilat ESE mengandungi 68 keping dan dibina mengikut piawaian NFC17102 (Perancis). Kesan kilat langsung 150 kA kemudiannya disimulasikan pada jana kuasa PV menggunakan MATLAB/Simulink. Akibatnya, sistem perlindungan kilat (LPS) ESE melindungi dan menghalang serangan kilat dengan berkesan. Kesan teduhan dan kos pemasangan (USD 10,026,800 lwn. USD 8,026,800) jenis rod Franklin juga lebih ketara daripada jenis rod ESE. Hasil ini menunjukkan bahawa LPS ESE sesuai untuk pelaksanaan jana kuasa PV. Penemuan kajian ini juga boleh membantu dalam mengoptimumkan teknologi perlindungan kilat untuk jana kuasa PV berskala besar.

Under continuous lightning strikes, the impulse dispersion characteristics of grounding devices more effectively indicate the effectiveness of tower grounding for lightning protection. These characteristics exhibit distinct behaviors under different lightning current pulse intervals. To investigate these characteristics, the present study employed ATP-EMTP simulation software to develop a dual-pulse model that accounted for the time-varying properties of soil and spark effects. The combined simulation and experimental approach was used to examine, the continuous impulse characteristics of grounding devices. The results reveal that the impulse characteristics under continuous strikes are significantly different from those under single strikes, primarily due to variations in the soil environment surrounding the grounding devices. The spark and recovery effects exert different impacts on soil impulse dispersion performance. Shorter pulse intervals lead to a superposition of first and second impulse currents, which increases current amplitude and spark effect, temporarily reducing soil resistivity and making the recovery effect of soil less pronounced. This results in lower impulse grounding resistance compared to longer intervals. Furthermore, with the increase in soil resistivity, the ratio of the second to the first impulse grounding resistance decreases, indicating that soil resistivity also influences the intensity of the spark effect on soil.

The tufting technology has the advantages of high flexibility and high economy. Research has found that metal tufting structures can significantly improve the mechanical and electrical properties of carbon fiber composites, and have great prospects in engineering applications. In order to investigate the damage characteristics of carbon fiber CFRP laminates with metal tufted structures during lightning strikes and the influence of structural parameters on lightning protection effectiveness, an electric thermal coupling model of CFRP laminates with metal tufted structures was established. Comparing the simulation and experimental results under the same load condition, it was found that the two were consistent in terms of damage appearance, damage area, and damage propagation trend, proving the effectiveness of the model. The transverse heat transfer process and current conduction path of CFRP laminates with metal cluster structure were discussed. The research results indicate that the ablation surface area of CFRP laminates with metal tufted structures is reduced to 8.06% of the reference component. Wire spacing had an effect on the area and shape of the area of the high potential region, and the wire spacing had the greatest impact on the ablation area of lightning strikes.

Lightning protection is important for weather radars to prevent critical damage or outages, but this can have negative effects on data quality. The existing lightning protection of the German Meteorological Service (Deutscher Wetterdienst, DWD) polarimetric C-band weather radar network consists of four vertical poles with a maximum diameter of 10 cm. During radar operation, these rods cause local scattering in the near field of the antenna, resulting in negative impacts on radar products. One effect is the removal of significant transmission power from the main beam axis and its addition to other areas or the side lobes. This results in wrongly localised precipitation fields in a radial direction. The second effect is the loss of transmitted and received power, appearing as a decrease in system gain, and subsequently an underestimation of all power-based radar moments in the vicinity of the rods. The underestimation in radar reflectivity Z then leads to a negative bias of approximately 20 % in the actual rain rate if a Z – R relationship is applied. These detrimental effects on data quality led to the requirement of developing a new lightning protection concept. The new concept must minimise the effect on data quality but also provide sufficient protection from lightning strikes according to the existing regulations and requirements. Three possible lighting protection concepts are described in this paper: two using vertical rods of different diameters (16 and 40 mm) and one with horizontally placed rods outside the antenna aperture. Their possible influence on data quality is quantified through a dedicated measurement campaign by analysing resulting antenna patterns and precipitation sum products. Antenna patterns are analysed with respect to the side-lobe levels compared to antenna patterns without lightning protection and the original lightning protection. With the newly tested lightning rods, the apparent side-lobe levels are slightly increased compared to an antenna pattern taken without lightning protection but are within the accepted antenna specifications. Compared to the original lightning protection, a decrease of up to - 15 dB in apparent side-lobe levels is found for all tested lightning protection options. Beam blockage is substantially reduced compared to the existing lightning protection, as shown by the evaluation of quantitative precipitation estimation (QPE) sums. These results and some structural considerations are a solid basis to recommend the installation of four rods with a maximum 40 mm diameter for all 17 radar systems of the DWD weather radar network. [ABSTRACT FROM AUTHOR]

Independent lightning rods are often installed in substation grounding systems for lightning protection. The concentrated discharge channel formed when a lightning current flows to the ground through a grounding electrode will cause electromagnetic interference to the directly buried secondary cable. And the three-dimensional structure of the discharge channel will affect the transient electromagnetic field distribution, thereby affecting the electromagnetic transients on cable shields. In order to explore the influence of soil discharge phenomena on the electromagnetic interference of the directly buried secondary cable, in this paper, we carried out experiments on cables in two different grounding modes, single-ended and double-ended grounding, and captured image of soil discharge channels. The results show that the cable grounding mode will affect the coupling mode that causes the shielding layer current. The relative spatial position of the soil discharge channel and the cable has a significant impact on the magnitude of the shielding layer current under both grounding modes. The water content and salt content of the soil also have different degrees of influence on the coupling current of the shielding layer in different grounding modes. [ABSTRACT FROM AUTHOR]

This paper investigates the impact of transmission line parameter calculation formulations on surge arrester performance in response to lightning strikes. This evaluation consists of comparing power and energy dissipated in surge arresters, as well as critical currents and line backflashover rates. The lightning performance of surge arrester installed in a typical Brazilian 138 kV transmission line is assessed by simulations in ATP software, while transmission line parameters are calculated in 3 different ways, namely: (i) Carson formulation, (ii) Nakagawa formulation considering the electrical parameters of the ground constant with the frequency, and (iii) Nakagawa formulation considering the frequency-dependent characteristics of the soil. Taking as reference the results determined by Carson's formulation (since this formulation is the most used in programs for calculating transients, such as ATP), it is shown that Nakagawa's formulations considering both constant and frequency-dependent soil parameters can lead to differences for the cases of unprotected lines, partially protected (lightning arresters in one or two phases) and fully protected (lightning arresters in all phases), resulting in an inaccurate prevision of insulation failure, leading to an increase in the backflashover rate. [ABSTRACT FROM AUTHOR]

The widespread use of composite materials with low electrical conductivity in modern advanced aircraft has placed higher requirements on lightning protection for airborne equipment. To ensure the safe operation of aircraft under a lightning environment, the internal cables and cable tracks of composite aircraft are modeled. The lightning protection performance of cables is calculated for different types and shielding parameters, and the effect of the cable layout inside a composite aircraft on the protection performance is analyzed. The role of the cable track in lightning protection is also verified. The calculation results show that the cable shield and track structure can provide good lightning protection for the cable in the electromagnetic exposure area, and the layout of the cable inside the aircraft has a greater impact on the protection performance. The analysis of cable shielding measures and their influencing factors can provide a reference for the performance improvement of cable screening measures for the lightning protection of composite aircraft. [ABSTRACT FROM AUTHOR]

Lightning is a common natural occurrence, particularly in tropical nations like Indonesia. This is because Indonesia is located closer to the equator than other sub-tropical nations, which increases the frequency of lightning strikes. Furthermore, Indonesia experiences a higher incidence of lightning strikes. If lightning strikes are not carefully predicted, they can be extremely dangerous, damaging infrastructure such as buildings and disrupting communication systems. Measuring the current of lightning strikes is crucial for this reason. There are numerous technologies available today to measure the current of a lightning strike. However, most of these technologies are not powerful enough to measure the high currents involved in lightning strikes. In this study, we discuss the construction of the Rogowski coil as a device for detecting the current of a lightning strike with a detection range of up to 100 kA. The Rogowski coil, which uses the electromagnetic principle to measure current, is a toroidal coil of wire with an air core. The Rogowski coil was chosen because it has several benefits, including the fact that it does not experience saturation, ensuring that the measurement results of the lightning current remain linear. Additionally, it is affordable and adaptable. An amplifier circuit, an integrator (low-frequency filter), and a phase shifter make up the conditioning circuit at the Rogowski coil's output. The results of the measurement are then made visible by connecting the circuit's output to an oscilloscope. The results of the lightning current measurements can be used to evaluate the tool's accuracy and subsequently serve as a guide for the implementation of a more effective lightning protection system in Indonesia. We hope that in the future, there will be no more damage to infrastructure due to lightning strikes caused by the failure of the protection system. [ABSTRACT FROM AUTHOR]

Introduction. Insulation coordination requires accurate prediction of overvoltages at various points within a substation. Computer simulations of electromagnetic transients in real structures of substations become more precise due to the improvements of used models. Goal. This paper discusses in a first step the use of the modified ZnO arrester dynamic model alongside other substation equipment models, considering electrical phenomena like the corona model for reproducing the stresses that lightning can cause in an air-insulated substation and (method) then conducting a statistical approach based on the Monte Carlo method. The implemented MATLAB/ATP procedure estimates not only the substation Mean Time between Failures (MTBF), but also is used to select surge arresters or substation basic insulation levels (BILs). In this procedure ATP transients program is used to calculate lightning overvoltages and multicore environment for the calculations. Results. The obtained MTBF curves offer guidance for selecting appropriate insulation levels based on specific system requirements and conditions. The obtained results comply well with existing international insulation standards. This valuable approach significantly contributes to the field of lightning protection. References 31, tables 3, figures 10. [ABSTRACT FROM AUTHOR]

Under continuous lightning strikes, the impulse dispersion characteristics of grounding devices more effectively indicate the effectiveness of tower grounding for lightning protection. These characteristics exhibit distinct behaviors under different lightning current pulse intervals. To investigate these characteristics, the present study employed ATP-EMTP simulation software to develop a dual-pulse model that accounted for the time-varying properties of soil and spark effects. The combined simulation and experimental approach was used to examine, the continuous impulse characteristics of grounding devices. The results reveal that the impulse characteristics under continuous strikes are significantly different from those under single strikes, primarily due to variations in the soil environment surrounding the grounding devices. The spark and recovery effects exert different impacts on soil impulse dispersion performance. Shorter pulse intervals lead to a superposition of first and second impulse currents, which increases current amplitude and spark effect, temporarily reducing soil resistivity and making the recovery effect of soil less pronounced. This results in lower impulse grounding resistance compared to longer intervals. Furthermore, with the increase in soil resistivity, the ratio of the second to the first impulse grounding resistance decreases, indicating that soil resistivity also influences the intensity of the spark effect on soil. [ABSTRACT FROM AUTHOR]

The effects of generating pulsed radiation by a long spark discharge are important for the development of lightning models and applications related to lightning protection. In experiments with a Marx generator simulating a lightning discharge, we detected the radiation in the form of a single ultrawideband electromagnetic pulse (UWB EMP) about 200 ps in duration, and rising time about 100 ps. UWB EMP generation occurs during the breakdown of a "rod–rod" 4 m long gap. Pulses of almost unipolar shape are observed in more than half of all positive discharges. EMP emission occurs before the main stage, and corresponds to the start of the upward leader from a grounded electrode. In negative discharges, pulses are also observed, but less frequently and with a smaller amplitude. The UWB EMPs, given their large amplitude (more than 100 V/m at a distance of 90 m from the discharge), can be considered as possible new lightning damage factors. Plain Language Summary: A Marx generator with an operating voltage of several megavolts is used to simulate a lightning stroke of a grounded object. The generation of a short electromagnetic pulse (several hundreds of picoseconds long) has been detected during a breakdown of a long air gap using special electromagnetic probes. Such a pulse is observed in the majority of positive discharges in the "rod–rod" gap. Subnanosecond pulse can be regarded as possible new damage factor of lightning strokes. Key Points: Marx generator allows studying generation of ultra‐wideband electromagnetic pulses (EMPs) by long spark discharges that model lightningSingle EMP about 200 ps duration is generated by 4‐m long spark discharge in a rod‐rod geometryPulses of almost unipolar shape with up to 200 V/m amplitude are observed at 90 m distance from more than half of all positive discharges [ABSTRACT FROM AUTHOR]

Compressive performances of composite structures can be significantly decreased due to the lightning strike damage, so the structures with lightning frighten must be considered lightning protection design. In this study, compressive experiments after lightning strikes were conducted on non‐protected, 12‐layer interlaminar carbon nanotube film (CNF) protected, and traditional surface silver coating (TSSC)‐protected composite laminates. A numerical analysis procedure was established, incorporating a lightning strike ablation damage simulation (LSADS) module and compressive residual strength calculation (CRSC) module. The procedure's effectiveness was verified by the experiment results. Based on this procedure, the compressive performances and the possible failure mechanism of laminates after lightning strikes were analyzed. The results show that the laminates with TSSC protection and 12‐layer interlaminar CNF protection can increase compressive residual strength compared with non‐protected laminates. The predominant compressive damages of the laminates after lightning strikes are fiber‐matrix shear damage and fiber fracture damage. Optimized one‐layer interlaminar CNF protection with a thickness of 0.36 mm can increase the laminate compressive strength but decrease the structural weight. This study offers a reference and basis for the lightning strike protection design of composite structures. Highlights: CNF in lightning strike protection of composite structures.Compressive failure mechanism of composite laminates after lightning strikes.A numerical procedure to evaluate lightning damage and compressive performances.Design of interlaminar CNF protection. [ABSTRACT FROM AUTHOR]

The growing use of thermoplastic composites (TPCs) like low-melting polyaryletherketone (LM-PAEK) matrices reinforced with unidirectional carbon fiber (CF) in aircraft structures presents a significant challenge in terms of lightning strikes and electromagnetic interference shielding during aircraft operations. This is due to the weak electrical conductivity of TPC structures, which results in widespread damage when struck by lightning. The repair and maintenance of these extended damaged sites can increase operational costs and loss of flights. Several lightning strike protection (LSP) systems have been developed and implemented to address these concerns. This study evaluated a highly conductive coating with a low filler rate for its effectiveness as an LSP solution for TPCs on exterior aircraft surfaces. The TPC panel without any coatings was first studied. Subsequently, the level of conductivity was increased by incorporating the nanoscale conductive fillers, silver-coated copper (Ag/Cu) nanoflakes, with a silver content of 20 wt.% (Ag20/Cu) and 30 wt.% (Ag30/Cu), correspondingly, into the coating at two loadings of 55 wt.% and 70 wt.% in an epoxy carrier for the surface coatings. The behavior of electrical and surface conductivity was thoroughly examined to understand the impact of Ag/Cu with a high aspect ratio and the effectiveness of the LSP solution. In addition, the spray-coated TPC panels underwent rigorous Zone 2A lightning strike testing using simulated lightning current, in agreement with the industry standard of Society of Automotive Engineers (SAE) Aerospace Recommended Practice (ARP) 5412B. Despite the higher resistance due to the lower conductive coating weight, the TPC panels with Ag30/Cu at loading of 70 wt.% achieved better results than those with Ag30/Cu at loading of 55 wt.%. This is evidenced by the minor structural delamination and CF breakage on the front surface, which proposes a new economic route for a sustainable post-processed LSP system in the aviation industry. [ABSTRACT FROM AUTHOR]

It is of great importance to choose low-cost, high-performance/efficient and operating and protection equipment in accordance with the applicable legislation in electrical facilities. It is necessary to make calculations for the selection of the most suitable cable/line, measuring and protection system equipment. In this study, panel-inverter compatibility calculation, voltage drop, current control, short circuit, lightning risk and protection calculations, grounding resistance and grounding conductor calculations and tilt angle calculation were made for a grid connected photovoltaic system with a power of 0.4 MWe. It has been calculated that the allowable voltage range and maximum powerpoint voltage values of the selected inverter are compatible with the panel system. With voltage drop and current control calculations, copper cable cross section for each inverter output and solar board output were found to be 3x70+35 mm2 and 2(3x185+95) mm2, respectively, and transformer low voltage busbar 60x10 mm2. In order not to deform the low voltage busbars in peak short-circuit current, they should be placed at 10 cm intervals for 80 cm length. According to the transformer low voltage side phase-earth short circuit current, the cross-section of the grounding conductor should be at least 53.97 mm2 copper conductor. In the lightning protection facility of the panels, according to the rolling sphere method, it has been calculated that the air termination rods should be at least 0.84 m above the upper point of the solar panel. The optimum fixed panel tilt angle was found to be 32.08°. The calculations used in the study will benefit the practitioners in the design of grid-connected photovoltaic systems, in the selection of the most suitable electrical equipment with minimum size. [ABSTRACT FROM AUTHOR]

The application of arresters is critical for the safe operation of electric grids against lightning. Arresters limit the consequences of lightning-induced over-voltages. However, surge arrester protection in electric grids is challenging due to the intrinsic complexities of distribution grids, including overhead lines and power components such as transformers. In this paper, an optimal arrester placement technique is developed by proposing a multi-objective function that includes technical, safety and risk, and economic indices. However, an effective placement model demands a comprehensive and accurate modeling of an electric grid's components. In this light, appropriate models of a grid's components including an arrester, the earth, an oil-immersed transformer, overhead lines, and lightning-induced voltage are developed. To achieve accurate models, high-frequency transient mathematical models are developed for the grid's components. Notably, to have an accurate model of the arrester, which critically impacts the performance of the arrester placement technique, a new arrester model is developed and evaluated based on real technical data from manufacturers such as Pars, Tridelta, and Siemens. Then, the proposed model is compared with the IEEE, Fernandez, and Pinceti models. The arrester model is incorporated in an optimization problem considering the performance of the over-voltage protection and the risk, technical, and economic indices, and it is solved using the particle swarm optimization (PSO) and Monte Carlo (MC) techniques. To validate the proposed arrester model and the placement technique, real data from the Chopoghloo feeder in Bahar, Hamedan, Iran, are simulated. The feeder is expanded over three different geographical areas, including rural, agricultural plain, and mountainous areas. [ABSTRACT FROM AUTHOR]

This paper elaborates on the hazard mechanisms of diff erent types of lightning, such as direct lightning, electrostatic induction lightning, and electromagnetic induction lightning. Based on on-site investigation and laboratory testing, this paper analyzes the pathways of lightning intrusion into ZPW-2000A track circuits, comprehensively analyzes the hazard mechanisms and intrusion pathways, formulates corresponding horizontal and vertical lightning protection measures, and explains the lightning protection characteristics such as "leakage", "resistance", and "suspension". [ABSTRACT FROM AUTHOR]

From the two decades, the utilisation of electronic equipment in aerospace applications drastically increased. High-intensity radiated fields highly influence the operation of electronic equipment. As per the survey, an economy flight is affected by a lightning strike for every 1000 hours of its journey. For the fabrication of the airplane structure, fibre-reinforced materials (FRP) were used, but there is a flaw in FRP's. FRP's having low conductance, which cannot flow the currents produced by the lightning strike, which causes delamination and embrittlement of the airplane structure. A different composite material was introduced as a lightning strike protection (LSP) layer to overcome the said problem. The electromagnetic protection is obtained in terms of reflection and absorption of the EM waves. Al6061 material is reinforced with SiC and flyash at different combinations and obtained good mechanical, absorption loss, and reflection loss properties. The maximum reflection loss of 32.61 dB and absorption loss of 32.60 dB was obtained. [ABSTRACT FROM AUTHOR]

This paper discusses main characteristics and features of the use of metal perforated foils and metal knitted and knitted–soldered wire meshes in the creation of effective lightning-protection systems for carbon composite structures. [ABSTRACT FROM AUTHOR]