Lightning-induced Voltages Research Articles

Lightning damage assessment on solar panels using in-house portable infrared thermography camera with Convolutional Neural Network (CNN) algorithm

ABSTRACT As the demand for renewable energy sources increases, the vulnerability of solar panels to lightning strikes becomes a critical concern. This research explores the correlation between lightning-induced voltage fluctuations and the resultant damage intensity on solar panels. The study adopts a systematic approach, first investigating the correlation between lightning-induced voltage assessment using 30kV, 60kV and 90 kV impulse voltage with multi-stage Marx impulse generator and the damage intensity on monocrystalline and polycrystalline solar panels. A portable active infrared thermography equipment with tCam-Mini was employed to conduct this research with wireless streaming. Furthermore, the study integrates Convolutional Neural Network (CNN)-based image classification techniques to enhance the efficiency of damage assessment. The results highlight the potential of neural networks in improving the accuracy and speed of image classification for damaged and undamaged samples. The findings contribute valuable insights into enhancing the resilience of solar panel systems against lightning strikes, ultimately advancing the reliability and sustainability of solar energy infrastructure. A new CNN model was developed to classify the images obtained from thermography with 90.21% accuracy for greyscale and 85.31% accuracy on thermal images.

Accurate Surge Arrester Modeling for Optimal Risk-Aware Lightning Protection Utilizing a Hybrid Monte Carlo–Particle Swarm Optimization Algorithm

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.

Lightning-induced voltages on low-voltage distribution lines

Special attention has been drawn to transients in low-voltage systems in recent years. As the surge withstand capabilities of low-voltage networks are much lower than those of medium-voltage lines, they are more susceptible to lightning-caused disturbances. One of the primary sources of overvoltages is related to indirect lightning strokes. Such overvoltages are highly dependent on the soil characteristics and generally tend to increase with the soil resistivity. Considering realistic conditions, this paper discusses the effects of different parameters on the phase-to-ground and phase-to-neutral lightning-induced voltages on the low-voltage side of a typical distribution transformer. In the case of high-resistivity soils or high ground resistance values, phase-to-ground voltages induced by indirect strokes can reach several tens of kilovolts. Phase-to-neutral voltages higher than 5 kV may be common if surge protective devices are not applied.

Lightning Location and Peak Current Estimation From Lightning-Induced Voltages on Transmission Lines With a Machine Learning Approach

Lightning Location and Peak Current Estimation From Lightning-Induced Voltages on Transmission Lines With a Machine Learning Approach

Investigation on Lightning-Induced Voltage for Photovoltaic System Considering Electromagnetic Coupling of Rooftop Structure

Investigation on Lightning-Induced Voltage for Photovoltaic System Considering Electromagnetic Coupling of Rooftop Structure

Indirect lightning performance of 10-kV overhead distribution lines

The lightning-induced voltage in 10-kV overhead distribution lines was calculated and analyzed using the Agrawal coupling model and second-order finite difference-time domain (FDTD) method. The influence of lightning position on lightning-induced voltage was analyzed using the concept of indirect lightning withstanding levels. To achieve the limiting effect on lightning-induced voltage in 10-kV lines, the installation density of surge arresters should not be less than 1 group per 200–300 m.

Correction to: Survey on analytical and numerical methods for lightning-induced voltages calculations

Correction to: Survey on analytical and numerical methods for lightning-induced voltages calculations

Survey on analytical and numerical methods for lightning-induced voltages calculations

Survey on analytical and numerical methods for lightning-induced voltages calculations

Statistical analysis of lightning-induced voltages on a matched experimental overhead line

Statistical analysis of lightning-induced voltages on a matched experimental overhead line

The RBF-FD and RBF-FDTD Methods for Solving Time-Domain Electrical Transient Problems in Power Systems

In this paper, the development and application of the radial basis function-finite difference (RBF-FD) method and the RBF-finite difference time domain (RBF-FDTD) method for solving electrical transient problems in power systems that are defined by the time-dependent ordinary differential equations (ODEs) and the time-dependent partial differential equations (PDEs), respectively, are presented. RBFs such as Gaussian (GA), Multiquadric (MQ), Inverse Quadric (IQ), and Inverse Multiquadric (IMQ) are used in these numerical methods to formulate the central finite difference approximations of the first- and second-order derivatives of a function. The algorithm of selecting “optimal” shape parameters for our basis functions is also applied, specifically to increase the accuracy of the suggested methods with regard to high accuracy needs. Finally, the accuracy, effectiveness, and applicability of our new approaches are evaluated through simulations of the switching transient voltages on a typical electrical circuit and a 220 kV single-phase transmission line, lightning-induced voltages on a 110 kV single-phase overhead distribution line, and transient voltages along two horizontal grounding electrodes excited by lightning impulse sources. The obtained numerical results demonstrate that our proposed RBF-based numerical approaches compare favorably to the traditional numerical methods.

A New Approach to the Evaluation of the Lightning Horizontal Electric Field Over a Lossy Ground Based on the Time-Domain Cooray–Rubinstein Formula Fitted by Orthogonal Polynomials

The calculation of lightning return stroke electromagnetic field is the basis for evaluating transmission line lightning-induced voltages. The Cooray–Rubinstein formula in the time domain is widely used to evaluate the horizontal electric field of lightning return stroke on a lossy ground, but the evaluation of the formula requires high computation cost. Therefore, this study presents a new approach to evaluate the Cooray–Rubinstein formula based on orthogonal polynomial fitting. This method converts the complex convolution in the Cooray–Rubinstein formula into the sum of multiple simple convolutions by using an effective truncation scheme of Legendre orthogonal polynomial and the second Chebyshev orthogonal polynomial. The objective is to realize an efficient evaluation method to the horizontal electric field of the lightning return stroke. On the premise of ensuring the calculation accuracy, the effectiveness and correctness of the proposed method are verified through numerical experiments. Moreover, the application of the time-domain Cooray–Rubinstein formula based on two orthogonal polynomial fitting methods is discussed. Compared with the existing numerical methods for solving the Cooray–Rubinstein formula, the proposed method is easy to implement and efficient, which provides a new idea for evaluating the horizontal electric field of lightning return stroke above the lossy ground in the time domain.

Effect of Eddy Current for Photovoltaic Module on Lightning-Induced Overvoltage Caused by Electromagnetic Coupling

Lightning electromagnetic field will induce a high voltage on the photovoltaic (PV) farm and also generate the eddy current. To study the effect of eddy current inside a PV module, the mechanism of the eddy current is elucidated. The density of eddy current is derived and it is solved by the method of moments. The eddy current produces a magnetic field to weaken the original field, which can reduce the lightning-induced voltage. The eddy current is mainly distributed on the outside surface of both aluminum-back surface field solar cells and aluminum foil. Moreover, the lightning transient of a PV array is computed. It is concluded that the PV backsheet cored with aluminum foil can greatly reduce the differential-mode-induced voltage of PV module. Several crucial factors, including foil material, foil thickness, and the distance to solar cells, are discussed. In order to minimize the induced voltages of PV modules, the PV module with aluminum foil on backsheet is proposed and the suitable range of the foil thickness is determined.

Lightning Electromagnetic Fields Computation: A Review of the Available Approaches

Lightning represents one of the most critical issues for electrical infrastructure. In dealing with overhead distribution line systems, indirect lightning strikes can lead to induced voltages overcoming the critical flashover value of the line, thus damaging the insulators. The computation of lightning-induced voltages requires the modeling of the lightning current, the evaluation of the lightning electromagnetic fields and the solution of the field-to-line coupling equations. The numerical calculation of the lightning electromagnetic fields is time-consuming and is strongly dependent on the lightning channel modeling and soil properties. This article presents a review of the most widely adopted methods to calculate the lightning electromagnetic fields, starting from the classical formulation, which requires numerical integration, and highlighting the most effective approaches that have been developed to reduce computational effort. This is done first for the case of a perfectly conducting ground, then the available formulations to account for the ground finite conductivity are presented together with their possible implementations in both the frequency and time domains.

A Thévenin-Type Version of the Extended Modal-Domain Model for Lightning-Induced Voltage Calculations

In this paper, a new procedure is proposed for determining the external current sources required for evaluating lightning-induced voltages on overhead lines with the extended-modal domain (EMD) model. Unlike the original model, in which the calculation of the inducing current sources depends on the fitting of the characteristic admittance of the line, in the proposed procedure this calculation is performed using the characteristic impedance of the line. This significantly simplifies the use of the EMD model because now all parameters can be readily obtained from the built-in fitting tool that is usually available in electromagnetic transient programs to derive the parameters of Marti’s transmission line model. The validity of the proposed procedure is demonstrated through examples that indicate its accuracy in the calculation of lightning-induced voltages on overhead distribution lines terminated with different types of loads, including transformers and surge arresters, and multiple grounding points.

Mitigation of Insulator Lightning-Induced Voltages by Installing Parallel Low-Voltage Surge Arresters

In this paper, we propose a mitigation method for reducing lightning-induced insulator voltages based on the installation of low-voltage surge arresters aligned parallelly to the insulator. The three-dimensional finite-difference time-domain (FDTD) method is applied to numerically model a real surge arrester residual voltage evaluation system. The application of a transient current pulse, typical of lightning discharges, is considered in our numerical model. We considered cases with one or two surge arresters installed per phase, in three different geometric and parametric configurations for installing distribution surge arresters. In addition to the Kirchhoff current division, which reduces both the absorbed energy and the thermal stress, the results associated with the installation of two surge arresters parallelly aligned to the insulator show that the interaction of magnetic fields generated by the surge arresters’ currents can produce an additional strong reduction in lightning-induced voltage over the insulator, as presented in this paper. Conditions for maximum voltage reduction are also identified. A brief cost-effectiveness analysis is also provided.

A Novel Transient Model of Photovoltaic Module Considering Electromagnetic Coupling

Photovoltaic (PV) arrays are threatened by lightning strikes due to the wide-open installation area. Lightning surges can not only damage the insulating structures of PV modules but also reduce the efficiency of a cell. Considering the electromagnetic coupling between the PV-cell string and the metal frame, a novel transient model of PV module is developed in this article. The proposed model is compared with the method of moments and validated by the previous experimental results. The effect of PV-cell wiring on lightning-induced voltage is comprehensively analyzed. The result indicates that the induced voltage of PV module is determined by the impulse magnetic field. The wiring scheme has a great impact on the induced voltage since it changes the area of the loop. The lightning overvoltage between the PV module and the bracket can be reduced by the use of an additional down conductor. The proposed model is more comprehensive and efficient than previous studies. It can be used to evaluate the induced voltage of PV module and predict the failure mode of the bypass diode caused by a lightning strike.

Simulations and Experimental Validation of Lightning-induced Voltages on a PV System in Both Common Mode and Differential Mode

Simulations and Experimental Validation of Lightning-induced Voltages on a PV System in Both Common Mode and Differential Mode

Analysis of the Influence of the Earthing Resistance of Pylones on the Performance of the HVAC Line Facing Electromagnetic Transitories Lightning

The roles of electrical energy no longer need to be demonstrated since the industrial revolution of 1740 based on the use of new sources of energy, of which electrical energy is considered to be one of the greatest revolutions in the world. Despite this, we must note that electrical energy is changing the habits of human activity and, on the one hand, has consequences on its transport, the large quantities of which are transmitted by power lines, forcing them to operate more and more. more within their limits and unplanned outages increase the risk of instability. Storms, industrial pollution, and lightning strikes are the main causes of these unscheduled outages. In regions with a high keraunic level, the reduction of insulation breakdown due to lightning is, therefore, a major concern for designers and operators of HV lines. It is possible to reduce the number of tripping of power lines due to lightning by the proper installation of ground wires and by the appropriate grounding of pylons. In this article, we focus our research on the analysis of the impact of the earthing of the pylons on the performance of HV lines against lightning strikes. Considering these parameters and using the oldest and simplest analytical model as a time-varying current wave whose model is a difference of two decaying exponentials, we brought into contribution Maxwell's equations, the law of Ohm, telegrapher's equations, transmission line theory, and the FDTD method to model lightning-induced voltages as a function of HVAC tower grounding. This study was carried out on the Liminga-Funa 220 kilovolt alternating line in the DRCongo, located in a region where storm activity and industrial pollution are very high. Thus, the results obtained by simulation show that the peak voltage on the components of the HVAC line is a linear function of the impedance of the earthing of the pylon. The impedance value of the pylon earthing less than or equal to 10 Ohm dampens the atmospheric overvoltage and ensures good coordination of the insulation of the line elements in the event of a lightning strike at the top of the pylon for the first bow. But for the return arc taken in this case, the bypass of the insulator is unavoidable. The fractal dimensions of the results of our programs have been compared with those of the figures obtained experimentally.

An Efficient Method for the Computation of Electromagnetic Fields Associated With Tortuous Lightning Channels

Lightning electromagnetic (EM) fields are typically computed by assuming the current propagation within a straight vertical channel of negligible cross section. However, it is well known that the lightning path is tortuous and this can significantly affect the radiated fields and the lightning-induced voltages on power lines. Lupò <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">et al.</i> (2000) proposed an analytical method evaluating the EM fields radiated by a tortuous channel assuming a step current source; to consider an arbitrary (realistic) current source, a slow-converging convolution integral was applied. The aim of this article is to reduce the computation time of such procedure by extending to the tortuous channel case the approach proposed by Brignone <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">et al.</i> (2021) for the evaluation of the lightning EM fields with arbitrary current source, originally developed for a straight vertical channel. The performances of the present method are evaluated by means of comparison with the solution proposed by Lupò <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">et al.</i> (2000), showing an excellent agreement with a significant reduction of the CPU effort. This in principle will allow the computation of lightning-induced overvoltages at both individual and statistical level without a prohibitive computational effort.

Use of Rusck Formula and Multi-Nonlinear Regression to Discard Events Required to Calculate the Lightning Performance of Overhead Lines

In this work, two heuristic techniques used to reduce the number of simulations of lightning-induced voltages, which are required to assess the lightning performance of distribution lines according to the Monte Carlo methodology, are presented. The first uses the Rusck Formula to discard the events that do not cause damage to the line. The second is based on a multi-nonlinear regression of the previously simulated events. Both techniques were applied to estimate the flashover rate of straight and complex lines above flat ground with finite conductivities. As a result, between 80 % to 90 % of the total number of simulations were eliminated with a reduced error.