Search

In this study, we analyze a lightning event, which occurred on March 20, 2020 at 8:05 pm. Three other-triggered upward lightning developed simultaneously from the 150 m high Peissenberg Tower and from two small structures, a 35 m high mast and a 25 m high Church Tower. The velocity of the upward leaders ranged from 2.1 × 104 to 4.1 × 104 m/s. In addition, to these upward leaders, the total of 51 isolated leaders were observed. These leaders had no contact to the lightning channel or to other leaders or to objects at ground, i.e., most of them did not develop along a path of the decayed channel of a previous leader. Therefore, it is doubtful whether the isolated leaders may be recoil leaders. The lightning to the Peissenberg Tower was a bipolar flash with a current, which contained several (unusual) positive and negative components. The first component was a negative initial continuous current (ICC), followed by a strong negative current component, with a maximum of 4.1 kA and a duration of 40.2 ms. This current component was superimposed by a pulse train of 26 extremely strong current pulses with peak values up to 1.87 kA. The negative current component was followed by a positive current pulse with a peak value of 31 kA, a 10%–90% risetime of 1.80 ms, an action integral of 0.68 MJ/Ω, a full width on half maximum of 0.67 ms and a duration of 15.7 ms. The positive current pulse was superimposed by strong oscillations with the frequency of about 5 kHz and with amplitudes up to 10.2 kA. After its cessation, the positive current pulse turned into a negative continuing current with the duration of 217 ms, the maximum of 245 A, and the transferred charge of 18.0 C. The negative continuing current was followed by a negative return stroke which in turn was followed by a positive continuing current, which lasted 19.7 ms and had a maximum of 173 A. Finally, a second negative return stroke occurred, which was followed by a short negative continuing current with an M-component. [ABSTRACT FROM AUTHOR]

When a lightning strikes a high object, the current flows along the object and produces in this way a field component additional to the field radiated from the lightning channel. This additional field component enhances the field compared to lightning to flat ground. In this article, the field enhancement is analyzed for lightning striking the Peissenberg Tower, Germany. The analysis is based on investigations of the far field at distances from 10 to 1000 km. In the computer simulations, the return stroke process is taken into account with the transmission line (TL)-model and the tower is modelled with the computer program CONCEPT II based on the method of moments. In a first step, the pure effect of the tower is analyzed. In this case, the ground is taken into account as perfectly conducting plane. In the next step, the effect of the field propagation is added by introducing an attenuation function based on the solution of Sommerfeld and a far-field approximation of Norton. For fast rising return stroke currents and relatively near distances between 10 and 30 km, the field enhancement may exceed 100%. The field enhancement decreases strongly with decreasing soil conductivity (σ) and increasing distance (s), while the influence of the permittivity (ϵ) is rather small. At a distance of more than 100 km the field enhancement is typically in the range of some tens of percent. This result agrees well with the data of the European lightning location system EUCLID. From EUCLID an average field enhancement of about 20% is reported for lightning striking the Peissenberg Tower. [ABSTRACT FROM AUTHOR]

In this paper, we present current pulses from upward lightning, which have been measured since 2011 at the new top structure of the Peissenberg Tower, Germany. The study comprises 38 negative and two positive flashes, which contained 199 current pulses. About 49 of them were return stroke current pulses, 133 of them were current pulses, which superimposed the initial continuous current (ICC-pulses), and 17 of them were M-component current pulses, which superimposed the continuing current of a preceding return stroke. The current pulses are used to evaluate the performance of the European lightning location system EUCLID. Fifty one (25.6%) out of the 199 current pulses were detected by EUCLID, 40 (81.6%) return stroke current pulses, and 11 (8.5%) ICC-pulses or M-component current pulses. The peak currents ranged from 0.1 to 40.8 kA. Two groups of current pulses could be identified. The first group is related to branches of nearby downward lightning which got in contact with the tower. Therefore, EUCLID reported much higher peak currents (more than 100%) compared to the peak currents measured at the Peissenberg Tower. The first group comprises the total of nine current pulses (six ICC-pulses, three return stroke current pulses). The second group of current pulses is related to upward lightning initiated from the top of the tower. The peak current inferred from EUCLID deviates much less from peak current measured at the Peissenberg Tower. The peak current was overestimated by about 20% by EUCLID. The second group comprises the total of 42 current pulses (4 ICC-pulses, 1 M-component current pulses, and 37 return stroke current pulses). The peak currents ranged from 3.1 to 40.8 kA, the geometric mean (GM) was 9.4 kA. About 30% of these events were misclassified as intra-cloud pulses by EUCLID. The GM of the location error was 161 m for all events, and 132 m considering only the return stroke current pulses. [ABSTRACT FROM AUTHOR]

The main objective of this paper is to evaluate the maximum share of the lightning current, which enters a building on electric installation lines. The conductors of the power circuit are equipotentially bonded to the air-termination or down-conductor system at roof level. For live conductors, the lightning equipotential bonding is realized by the use of surge protective devices (SPD), which have to withstand the threat of the share of the lightning current. The most important parameter is the maximum transferred charge, which was calculated by the use of the computer code CONCEPT II. The maximum expected charge is about 0.6 C for buildings with metal façades. If the building is additionally equipped with a metal roof, or, if the roof, the ceilings and the pillars/walls consist of reinforced concrete, the maximum expected charge is 0.1 C. For buildings without shielding elements (metal roof, metal façade, reinforced concrete), the charge is much higher, in the range of several coulombs. The values only apply to spark-type SPD and to building up to heights of about 15 m using copper or aluminum for the air-termination and down-conductor system. The transferred charge is significantly higher, if the air-termination and down-conductor system consists of stainless steel. [ABSTRACT FROM AUTHOR]

In this paper, we present the currents, which have been measured since 2008 at the new top structure of the Peissenberg Tower, Germany, and the associated electric fields in a distance of about 180 m from the tower. The study comprises 17 negative lightning, which contained 44 subsequent return strokes, 108 initial continuous current (ICC)-pulses, and 26 M-components. The analysis, based on the current waveform, revealed three different types for both the M-component current and the ICC-pulse. The impulsive current of type 1 has a more or less symmetrical wave shape. For this type, the electric field occurred on average 15.7 μs prior to the current pulse. The impulsive current of type 2 has a bipolar wave shape with current reversal. The impulsive current of type 3 has a wave shape, which exhibits a fast rise to peak and a much longer decay to low current values. For all types of impulsive currents (return strokes, ICC-pulses, and M-components), the electric field exhibits a first field change (ΔE1) followed by a second field change (ΔE2) of opposite polarity. For the ICC-pulses and M-component currents of types 1 and 3, the first field change (ΔE1) has typically an initial slow-rising section, which is followed by a fast-rising section. The transition point was time-correlated with the onset of the current. The transition point was at about ΔE1/3 for type 1 and at about ΔE1/2 for type 3. For type 2, the onset of the current pulse occurred during the second field change (ΔE2) of opposite polarity. Similar to type 1 and 3 pulses, the slow-rising electric field changed into a fast-rising electric field. The transition point for type 2 pulse was at about ΔE2/3. From the 44 subsequent return strokes, 8 of them contained one negative M-component of type 1. In that case, the M-component current was extremely strong. The arithmetic mean (AM) was 8.5 kA (GM: 5.4 kA) for the peak current and 747.8 mC (GM: 614.0 mC) for the transferred charge. The return stroke was also very strong, with an AM of 16.7 kA for the peak current (GM: 15.0 kA). In comparison, the AM was 10.4 kA (GM: 8.3 kA) considering all subsequent return strokes. [ABSTRACT FROM AUTHOR]

This paper gives the overview and review of the traveling current source (TCS) model, which describes the electrical processes during the lightning return stroke. It is shown that the main characteristics of the measured electric and magnetic fields can be reproduced with the TCS model. These are the ''initial peak” of the electric and magnetic field for near, intermediate and far distances, the ''ramp” (up to the maximum) of the near electric field, the ''hump” of the near magnetic field after the initial peak, and the ''zero crossing” of the far distant electric and magnetic field. The TCS model is based on the assumption that the lightning current is injected at the top of the increasing return stroke channel represented by a transmission line. The original model is presented and then extended to take into account the current reflections occurring at ground and at the upper end of the return stroke channel. To this end, the ground reflection factor ρ and the top reflection factor R are introduced. Due to the increasing return stroke channel, the top reflection factor is a function of the return stroke velocity. The total current is composed of the source current according to the original TCS model and the reflected currents. An example shows that the ground reflection causes significant variation in the peak values of the channel-base current and of the maximum current derivative. A major effect was also found for the initial peak of the electric and magnetic fields calculated at 3 km distance. [ABSTRACT FROM AUTHOR]

Channel base currents from natural lightning have been measured on the new top structure of the Peissenberg Tower, Germany, since 2008. Here, an analysis is given of the impulsive currents, called initial continuous current (ICC)-pulses, that occurred during the ICC, and of the impulsive currents, called M-component currents, that occurred during the continuing current following return strokes. It was found that the M-component currents and the ICC-pulses closely resemble each other. The 45 flashes analyzed were exclusively negative upward lightning containing 60 return strokes and 264 impulsive currents (79 M-components and 185 ICC-pulses). A total of 246 (93.2%) impulsive currents were negative ones, and 18 (6.8%) impulsive currents were positive ones. The majority of 83.7% were pure impulsive currents and the minority of 16.3% were combined impulsive currents composed by two or more pure impulsive currents. For the pure impulsive currents, the analysis revealed three different types of waveforms for both the M-component currents and the ICC-pulses. The currents of the first type have a more or less symmetrical wave shape. For the 27 M-component currents and the 103 ICC-pulses (values in parentheses) of the first type, the geometric mean values are 0.7 (0.5) kA for the peak value, 23.9 (24.7) μs for the 10%-to-90% risetime, 101.0 (96.5) μs for the full width at half-maximum (FWHM), and 94.3 (57.1) mC for the transferred charge. The impulsive currents of the second type have a bipolar wave shape with current reversal. For the 31 M-component currents and the 37 ICC-pulses of the second type, the geometric mean values are 0.9 (0.6) kA for the peak value, 11.8 (16.9) μs for the 10%-to-90% risetime, 60.6 (74.7) μs for the FWHM, and −42.4/58.5 (−34.1/26.5) mC for the negative/positive charge of the bipolar pulses. The impulsive currents of the third type have a wave shape, which exhibits a fast rise to peak and a much longer decay to low current values. For the 5 M-component currents and the 18 ICC-pulses of the third type, the geometric mean values are 1.0 (1.2) kA for the current peak, 1.2 (2.9) μs for the 10%-to-90% risetime, 56.8 (29.0) μs for the FWHM, and 44.8 (24.03) mC for the transferred charge. [ABSTRACT FROM AUTHOR]

Subject matter of this paper is the analysis of the total of six upward positive lightning initiated from the Peissenberg Tower, Germany. All of them occurred during the cold season from February to April in the years 1997 to 1999. Three of them were initiated without nearby preceding lightning activity (called “self-initiated” upward lightning) and the other three occurred during nearby lightning activity (called “other-triggered” up-ward lightning). The analysis suggests that the other-triggered upward lightning is a downward lightning involving a relatively long upward connecting leader. The first current component, however, was different from the current of a first return stroke of a positive cloud-to-ground flash. On average, the duration was 15.7 ms, the maximum was 4.37 kA, and the charge was 13.3 C. Due to the long duration and the relatively low current, the first current component is more consistent with the initial continuous current (ICC) of an upward lightning. The initial period of the ICC exhibits a slowly rising portion lasting about 1 ms. During that period, the ICC was superimposed by weak current pulses. The arithmetic means of the pulse peak and the pulse duration were 0.49 kA and 9.6 μs, respectively. The average leader velocity was \bf \bf 2.3 \, \bm \times \,\bf 10^\bf 5 m/s and the average leader charge density was \bf 1.02 \, \bf \times\, \bf 10^\bf -3 C/m. Much stronger current pulses were observed after that initial period. Then, the arithmetic means were 5.3 kA for the pulse peak and 46.6 μs for the pulse duration. The ICC of the self-initiated upward lightning did not exhibit such an initial slowly rising portion with weak superimposed current pulses. The ICC immediately increased to several kilo-amperes involving strong current pulsation. For the ICC, the arithmetic means were 58 ms for the duration, 6.4 kA for the maximum, and 105 C for the charge. For the current pulses, the arithmetic means were 5.7 kA for the pulse peak and 19 μs for the pulse duration. The leader charge density was estimated to be up to several 10 mC/m. [ABSTRACT FROM PUBLISHER]

This paper analyzes the slow-varying electric fields and the associated currents of a total of 35 negative upward lightning initiated by the Peissenberg tower, Germany. Thirty-four of which were from winter upward lightning and only one from summer upward lightning. It appears that all of the winter upward lightning were initiated without nearby preceding lightning activity (called “self-initiated” lightning) and only the summer lightning was triggered by nearby lightning activity (called “other-triggered” lightning). The slow-varying electric fields of the winter upward lightning showed a fast rise characterized by the 10–90% risetime, with an arithmetic mean of 13.8 ms. After attaining the maximum, the electric field turned into a slow decay being characterized by the time on half value which was evaluated to having the arithmetic mean of 441 ms. Transported charges to ground were on average 44.8 C and on maximum 165 C. The maximum value of the electric field was 39.9 kV/m on average, with the highest value being 64.5 kV/m. For the electric fields, higher values were prevented by recovery effects such as the corona from objects at ground and the redistribution of the charge in the thundercloud. Due to these effects, no or only weak correlations were found between the 10–90% risetime, the time on half value, the charge, and the maximum of the electric field. From additional measurements with a field mill, it was found that the electric field recovers to the starting level within some seconds. [ABSTRACT FROM PUBLISHER]

This paper presents a numerical electromagnetic analysis of loop-termination voltages inside an outer lightning protection system (LPS) resulting from direct lightning strikes. The method of moments is combined with the transmission line model, and employed to model the whole structure in three dimensions and the lightning channel, respectively. Three distinct standard LPS classes and a nonstandard LPS are modeled, namely, LPS1, LPS2, and LPS4, and LPSO, respectively. All cases are simulated using the negative subsequent stroke current at lightning protection level II according to LEC 62305-1. Three distinct current waveforms are selected in order to simulate the variety of different current rises. Three single-phase parallel vertical loops are simulated inside the struck LPS. The results reveal that reducing the LPS mesh width improves its shielding performance, where this may be a basic method to damp the lightning-induced voltages with little dependency on the strike location, and without any appreciable effect of the LPS material. The variation of the lightning-current front shows that the loop-termination voltages are altered within a factor of about 2. Existence and interconnection of extra protective earthing, e.g., via information technology cables, and the value and type of the loop-termination impedance also have significant influence on such voltages. [ABSTRACT FROM AUTHOR]

This paper presents a numerical electromagnetic analysis of magnetic fields and loop voltages inside reduced- and full-scale lightning protection systems (LPSs) ‘structures’ resulting from direct lightning strikes. The method of moments is employed to model the whole structure in three dimensions except the lightning channel. The lightning channel is simulated by the well-known transmission-line model (TL model), where the influence of the lightning-channel generated electric and magnetic fields are taken into account. Three distinct LPSs were modeled, namely, reduced-scale model with return conductors (RSRC), reduced-scale model with lightning channel (RSLC), and full-scale model with lightning channel (FS). The computed results of magnetic fields and magnetic-field derivatives were verified versus some experimental results for the RSRC model. In addition, the scale factor for all the measured quantities were also checked as functions of the geometrical scale factor for the positive and the negative first stroke currents. The lightning Shielding performance with and without bonding was investigated for three distinct lightning stroke types, namely, the negative first, the negative subsequent, and the positive strokes. The voltages and currents generated in loops located inside the struck FS LPS were computed with and without bonding and grounding resistance and for different lightning current waveforms, locations and inclination of the lightning channel, and return stroke velocity. [ABSTRACT FROM AUTHOR]

This paper presents measurements of the voltages, the magnetic fields and the magnetic-field derivatives inside a structure simulating reinforced concrete buildings. The test structure comprises a cubic cage of 2-m side length with single- or double-layer reinforced grids. The injected lightning currents simulate the positive, the negative first and the negative subsequent return strokes with amplitudes of ∼ 77, 16, and 4.8 kA, respectively. Three distinct points of the lightning stroke impact to the structure roof are considered, namely, the center, the mid-edge and the corner. In the case of a single-layer cage, the results reveal that slow-rising magnetic-field components are generated inside the structure for various lightning currents. This effect becomes dominant for the case of the double-layer cage. For all the simulated currents, striking to the structure corner induces the lowest voltage across it, but gives the highest values for both the resultant magnetic fields and the magnetic-field derivatives. For all striking points, the magnetic fields have the highest values for positive strokes, while the negative subsequent strokes give the highest amplitude of the resultant magnetic-field derivatives and roof-to-floor voltages. Compared to the case of a single-layer cage for the negative subsequent strokes, the use of a double-layer cage shows a considerable mitigation of the voltage across the structure, and a moderate mitigation of both the resultant magnetic fields and the magnetic-field derivatives. [ABSTRACT FROM AUTHOR]

This paper addresses a numerical electromagnetic analysis of the influence of installing passive shield wires "extra ground wires" (EGW) underneath the bottom phase conductor on the lightning shielding performance of 765-kV, 3-phase, double-circuit transmission lines. The method of moment (MOM) is employed to model the whole structure in three dimensions except the lightning channel. The lightning channel is simulated by the well-known transmission-line model (TLM), where the influence of the lightning-channel-generated electric and magnetic fields (EMF) are taken into account. The lightning shielding performance with and without EGW is introduced and discussed, without ac energization and due to three distinct lightning strokes, namely, the negative first, the negative subsequent and the positive strokes. The produced voltages and currents in the phase conductors and ground wires as well as the voltage across the insulators are computed, with and without the EGW, due to different lightning current waveforms, locations and inclination of the lightning channel, and return-stroke velocities. The introduction of such EGW results in a significant improvement of the shielding effectiveness by reducing the lightning-produced voltages and currents in the phase conductors as well as the voltage across the insulators. Accordingly, a much lower transient overvoltages can be expected with less inadvertent outages of the lines, where the probabilities of flashover and back-flashover decrease, and the reliability enhances. [ABSTRACT FROM AUTHOR]