Measurements and modeling of electromagnetic disturbances in the lightning protection system of the residential building (original) (raw)
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The distribution of lightning current in the lightning protection system (LPS) and the electrical circuit of two test structures simulating residential buildings was experimentally studied at two research facilities in Florida and in Poland. In Florida, the experiments were conducted using rocket-triggered lightning, and in Poland a mobile current surge generator was employed. The soil in Florida was sandy, while in Poland it was mostly clay. Simulations of lightning current in the LPS and the electrical circuit of each of the test structures were also performed. In this paper, we present results of experiments and numerical modeling of lightning current distribution in different configurations of LPS installed on the test structures at the two sites.
IEEE Transactions on Power Delivery, 2000
We present the results of structural lightning protective system (LPS) tests conducted in 2004 and 2005 at the International Center for Lightning Research and Testing (ICLRT) at Camp Blanding, FL. Lightning was triggered using the rocket-andwire technique, and its current was directly injected into the LPS. The test configurations in 2004 and 2005 differed in the lightning current injection point, number of down conductors, grounding system at the test house, and the use of surge protective devices.
Journal of Electrostatics, 2009
An in-depth knowledge about the characteristics of lightning generated currents will facilitate evaluation of the interception efficacy of lightning protection systems. In addition, it would aid in extraction of valuable statistics (from measured current data) on local lightning parameters. Incidentally, present day knowledge on characteristics of lightning induced current in typical lightning protection systems is rather limited. This is particularly true with closely interconnected protection systems, like the one employed in Indian Satellite Launch Pad-II. This system is taken as a specific example in the present study. Various aspects suggest that theoretical modelling would be the best possible approach for the intended work. From the survey of pertinent literature, it is concluded that electromagnetic modelling of lightning return-stroke with current source at the channel base is best suited for this study. Numerical electromagnetic code was used for the required electromagnetic field solution and Fourier transform techniques were employed for computing time-domain results. A validation for the numerical modelling is provided by laboratory experiments on a reduced scale model of the system. Apart from ascertaining the influence of various parameters, salient characteristics of tower base currents for different kinds of events are deduced. This knowledge can be used in identifying the type of event, as well as its approximate location. A method for estimation of injected stroke current has also been proposed.
American Journal of Applied Sciences, 2007
In this study we present and analysis of the return-stroke lightning current and described their models which existing in the literature by several authors for the evaluation of radiated electromagnetic fields and modelling the coupling with electrical systems based on the calculation of induced voltages. the objective of this work is to take part in the improvement of the coordination of electric insulations and to put device also for calculation of the over-voltages induced in the electrical networks by the indirect lightning strokes which represent the most dangerous constraint and most frequent. A comparative study between the existing models and the analysis of the parameters which affect the space and temporal behaviour of the current lightning strokes as well as the importance of the lightning current at the channel base form the essential consequence of this study.
A simulation model for electromagnetic transients in lightning protection systems
IEEE Transactions on Electromagnetic Compatibility, 2002
_ This paper deals with the evaluation of electromagnetic transients in a lightning protection system (LPS). A field-approach is used, based on the numerical solution of a modified version of the thin-wire electric field integral equation in frequency domain. Time profiles of electromagnetic interesting quantities are computed by using a discrete fast Fourier transform algorithm. The model takes into account coupling effects among aerial parts and ground electrodes in order to correctly estimate the quantities which can determine electromagnetic hazard inside the LPS; transient touch and step voltages can be easily evaluated also taking into account the human body presence on the soil surface. To this purpose, a crucial point is the accurate evaluation of the currents distribution among the earthed branches of the LPS and this needs to correctly consider mutual electromagnetic interference among the aerial parts and the earth-termination system of a same LPS. A suitable approach to consider the lossy soil is employed. Validation of the proposed model is performed by comparing the results with those measured and computed available in technical literature. Simulation examples related to realistic LPS structures are presented and discussed to show the flexibility and the accuracy of the model in the range of practical applications inside the volume to be protected.
This paper presents results of the electromagnetic field generated by different configurations of protection structures, when lightning strikes such structures. The transitory of current in the structure, and the return current is taken into account in the calculation of the field. This paper also presents an elegant expression for calculating the resultant electromagnetic field produced by a transient on cable currents or transmission lines. By taking into consideration a line disposed arbitrarily in the Cartesian coordinate system, using the Maxwell equations and applying the magnetic potential vector, we come to the generalized expressions for the electric and magnetic fields as a function of current and position in the time domain. This expression is a generalization of the expression proposed by Christopoulos in [l]. The method has been shown to be very useful in applications where lines are disposed in arbitrary manners and especially in systems in which various lines are interconnected, such as lightning protection systems (LPS) or a grounding system. The results obtained with such expressions are compared to other numerical methods. The results are obtained applying TLM (Transmission Line Modeling) method to obtain the current transient.
Transient electromagnetic hazard inside a lightning protection system
This paper deals with the evaluation of electromagnetic (EM) hazard in a lightning protection system (LPS), by taking into account coupling effects among aerial parts and earthed electrodes in order to improve the computation of the quantities which can determine hazard inside the LPS. Field-approach is used; the computer code, entirely developed by the authors, is based on the numerical solution of the well-known thin-wire electric field integral equation in frequency domain. Time profiles of electromagnetic quantities are evaluated via fast Fourier transform. A suitable model to consider the lossy soil in a simplified way is proposed.
Przeglad Elektrotechniczny
In order to have a fast determination of electromagnetic fields peaks associated with inclined lightning channel, the analytical electromagnetic field expressions were proposed, assuming a pulse shaped return stroke current at channel base and by considering the channel angle and the observation point angle effects on the electromagnetic fields. Also, the return stroke velocity effects on the peaks of electromagnetic fields were processed. The results were compared with the perpendicular lightning channel case. The proposed fields' expressions are very useful in determining the peak values of electromagnetic fields, since they are considered as critical parameters in estimation of lightning induced voltage peak on the power line.
Journal of Electrostatics, 2004
In IEC 61312-2 equations for the assessment of the magnetic fields inside structures due to a direct lightning strike are given. These equations are based on computer simulations for shields consisting of a single-layer steel grid of a given mesh width. Real constructions, however, contain at least two layers of reinforcement steel grids. The objective of this study was to experimentally determine the additional shielding effectiveness of a second reinforcement layer compared to a single-layer grid. To this end, simulated structures were set up in the high current laboratory. The structures consisted of cubic cages of 2 m side length with one or with two reinforcement grids, respectively. The structures were exposed to direct lightning currents representing the variety of anticipated lightning current waveforms. The magnetic fields and their derivatives at several positions inside the structure as well as the voltage between "floor" and "roof" in the center were determined for different current injection points. From these data the improvement of the shielding caused by a second reinforcement layer is derived.
Journal of Electrostatics, 2004
In the present paper, transient-induced voltages on a distribution line over finitely conducting ground, which are associated with lightning to a 200-m high stack, have been analyzed by Numerical Electromagnetics Code (NEC-2). An electromagnetic model (EM) of a lightning channel, which contains additional distributed inductance to simulate the reduced propagation velocity of lightning current, has been employed. Validity of the employed model which incorporates a tall structure and a lightning channel has been discussed by comparing calculation with measurements. r