In case of direct lightning strike to a building dangerous sparking may occur between the external lightning protection system and conductive installations inside the building. To avoid such side flashes a minimum separation distance between conductive parts inside the building and the air termination or down conductor system is required. The standard IEC 62305-3 provides formulae to determine the necessary separation distance. Objective of the paper is to re-visit the determination of separation distances. The international standard IEC 62305-3 recommends using electrically conductive parts of a building or structure as so-called 'natural components' of the lightning protection system. The use of such extended metal parts can lead to significant reduction of the necessary separation distances. Objective of the paper is also to study the necessary separation distances for buildings using metal roofs, walls or attics as integral part of the lightning protection system. Such configurations are not yet covered by the IEC-standards.

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... these coefficients consider the simplified constant steeped lightning current such as 200 kA/μs [6]. However, the actual current in a subsequent stroke to the LPS can be expressed using the mathematical function [7]. ...

In the event of a direct lightning strike to a protected building which is integrated with an electrical or electronic system installed on the roof such as roof-top PV system, dangerous arcing may occur between the external lightning protection system (LPS) and the conductive components of the electrical system. To prevent such side flashes, a minimum separation distance between the metallic components and the air termination system is required. Even though, IEC62305-3 Standard provides a formula to specify the necessary separation distance, so far there is no extensive study that has been done to evaluate the suitability of the application of equation to calculate the separation distance, specifically to the safety of electrical systems integrated into the roof top of building. In this study, a new computational method has been developed for calculation of the separation distance between an LPS and metallic components on the roof. In the proposed method which is based on the theoretical background of the IEC62305-3 Standard formula, the break down behavior of the gap geometry between the LPS and the metallic components for the applied voltage across the gap is analyzed. PSCAD software was used to model the LPS and the lightning strokes.

... Lightning protection system materials and condition of use[3,5,44,45,49,50].This table shows a general guide to materials that are normally used in a LPS. Steel, aluminium and copper are the three main metals used in grounding system applications. ...

... Lightning protection system materials and condition of use[3,5,44,45,49,50].This table shows a general guide to materials that are normally used in a LPS. Steel, aluminium and copper are the three main metals used in grounding system applications. ...

Lightning protection system elements need to be selected from materials which are resistant to corrosion and should be protected from fast degradation. However, over the time corrosion will take place in the presence of galvanically dissimilar metals in the same electrolyte (moisture). Historically, copper, aluminium and copper alloys (including bronze and brass) have been used in lightning protection applications as these materials are highly conductive and abundantly available. Corrosive effects on system components are influenced by the environmental factors such as moisture, soil type and temperature that make the corrosion process highly complex in soil. As per many standards on the installation of lightning protection systems, combinations of materials that naturally form electrolytic couples shall not be used, for example copper and steel, especially in the presence of moisture, in which corrosion will be accelerated. Similarly, the conditions within soil will have adverse effects on the ground system elements. Down conductors entering corrosive soil must be protected against corrosion by a protective covering. The paper presents the causes of corrosion and recent developments in minimising the corrosion associated with lightning protection and grounding systems.

... In the worst case, strike to the corner, this voltage reached value U § 2,7 MV. In this case, for calculation of separation distance s the constant-area-criterion [4,5,8] is used and the following equation must be fulfilled: ...

  • Andrzej Sowa

Devices or installations on the roof and walls or inside the structure should be protected against direct influence of lightning currents. To achieve such protection devices or installations should lie within the protective spaces and minimum separation distances between these devices and elements of air-termination or down-conductor systems are required. The objective of this paper is to study the values of separation distances for different configurations of lightning protection systems.

  • Andrzej Sowa

Devices or installations on the roof and walls or inside the structure should be protected against direct influence of lightning currents. To achieve such protection devices or installations should lie within the protective spaces and minimum separation distances between these devices and elements of air-termination or down-conductor systems are required. The objective of this paper is to study the values of separation distances for different configurations of lightning protection systems.

Abstract—This paper presents a study on the overvoltages that appear across the separation distance between LPS and structure conductive parts when the former is struck by lightning. The overvoltage calculation is carried out in frequency-domain using the Method of Moments and the results are translated to time-domain by Fourier transform. The structure is represented by its steelwork and the voltages are computed for the standard waveforms corresponding to negative first strokes and subsequent strokes. The likelihood of insulation breakdown is assessed by the Equal Area Method, which takes into account the voltage waveform. It is shown that, for non-insulated LPS, sparks between LPS and structure steelwork are very likely to occur, both for first and subsequent strokes. The results support the proposal of bonding the LPS to the building steelwork, regardless of the condition of the latter. The paper also discusses how this issue is addressed in the international standard for lightning protection of structures.

One of the newest methods in sheet metal forming is laser forming process. In this forming process, sheet metal is formed under high thermal stresses caused by laser heat. Some parameters are effective sheet metal forming by a laser that analyzed, such as laser beam diameter, scanning acceleration, laser power and etc. In all of previous researches on sheet metal forming by laser, laser power was constant. In this research, effects of variations of heat flux in laser forming of sheet metals are investigated by finite element method. To perform better sheet deformation by laser it is necessary to use an optimal function of the laser power. However, it was observed that the non-constant power path leads to a non uniform deformation.

  • J.F. Shipley

The British Standards Institution has just issued a set of Recommendations on this subject, which is the first authoritative general guidance that has been made available to the public in this country since the Report of the Lightning Rod Conference in 1881 and its amendment by the Lightning Research Committee in 1905. These new Recommendations have been adopted and published by the Codes of Practice Committee for Civil Engineering Works and Building formed under the aegis of the Ministry of Works and Planning. The Code of Practice should be referred to because in addition to the Recommendations it contains appendices in which comment is made on some of the new features dealt with, and which this paper to some extent amplifies. This paper does not deal with the protection of ships, aircraft or electric supply and telephone wires, but it attempts to throw light upon the problems connected with the protection of modern steel-framed and ferro-concrete structures. The need for protection is discussed and a rough attempt is made to assess the risk attached to any structure in any part of the world. The zone of protection receives attention and the presence of metal in the buildings is debated. The needs of structures which are very vulnerable to lightning, and of others which present difficult problems, are discussed. The components of a protective system, their materials and dimensions, together with their cost are referred to, and finally inspection, testing and records are dealt with.

  • M. A. Uman
  • R. D. Brantley
  • Y. T. Lin
  • Kenneth Mclain Kenneth Mclain

The first broad band (1 kHz to 5 mHz) correlated measurements of electric and magnetic fields from close lightning return strokes are presented. Sample wave forms are shown for the distance range 2-200 km. The transmission line return stroke model is used to find a typical current wave shape and return stroke velocity from the experimental data, and theoretical curves are given of electric and magnetic field as a function of time for 1, 5, 10, and 100 km by using this typical current and velocity.

Isolated lightning protection systems for buildings with flammable content

  • W Zischank

W. Zischank, "Isolated lightning protection systems for buildings with flammable content", Proc. of the 19 th International Conference on Lightning Protection ICLP, paper 6.8, Graz, April 1988 (in German).

Induced over-voltages at lightning protection systems with meshed air termination conductors

  • O Beierl
  • H Steinbigler

O. Beierl, H. Steinbigler, "Induced over-voltages at lightning protection systems with meshed air termination conductors", Proc. of the 18 th International Conference on Lightning Protection ICLP, Munich, paper 4.1, Sep. 1985 (in German).

Pulse generated electromagnetic response in three-dimensional wire structures

  • H Bruens

H. Bruens, "Pulse generated electromagnetic response in three-dimensional wire structures", Ph. D. Thesis, University of the Federal Armed Forces Hamburg, Germany, 1985 (in German).

Calculation of transient processes at direct lightning stroke into thin wire structures

  • H Bruens
  • H Singer
  • F Demmel

H. Bruens, H. Singer, F. Demmel, "Calculation of transient processes at direct lightning stroke into thin wire structures", Proc. of the 7th Symposium on Electromagnetic Compatibility, Zurich, paper 17D5, pp. 85-90, March 1987.

Analysis of necessary separation distances for lightning protection systems including natural components

  • F Heidler
  • W Zischank
  • A Kern

F. Heidler, W. Zischank, A. Kern, "Analysis of necessary separation distances for lightning protection systems including natural components", Proc. of the 28th Intern. Conf. on Lightning Protection ICLP, Kanazawa, Japan, vol. II, report X-1, pp. 1418 -1423, Sep. 2006.

Field Calculations by Moment Methods

  • R F Harrington

R.F. Harrington, "Field Calculations by Moment Methods", New York, The MacMillan Company, 1968.

CONCEPT II -Manual of the program system

  • H Singer
  • H Brüns
  • T Mader
  • A Freiberg

H. Singer, H. Brüns, T. Mader, A. Freiberg, "CONCEPT II -Manual of the program system", University Hamburg-Harburg, Germany, 2003.

Calculation and measurements of transient electromagnetic fields in EMP simulators

  • H Bruens
  • D Koenigstein

H. Bruens, D. Koenigstein, "Calculation and measurements of transient electromagnetic fields in EMP simulators", Proc. of the 6th Symposium on Electromagnetic Compati-bility, Zurich, paper 66L2, pp. 365-370, March 1985.