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Modern lightning protection systems for wind turbine blades with conducting structural elements, e.g., carbon fiber reinforced polymer (CFRP) spar caps, contain equipotential bonding joints to prevent sparking during strikes. Significant current levels are experienced through the joints and the characterization of the electrical contact at the bonding regions is essential for reliable protection. Therefore, this article aims to characterize the contact resistivity of several equipotential bonding joints. The proposed methodology first measures the total resistance of the samples, and then the bulk resistance of the conductive elements is computed using the finite-element method. The latter is required to predict the spreading effects in CFRP components due to the strong anisotropic nature of such materials. After that, the contact resistance is calculated by subtracting the predicted bulk resistances from the measured total resistances. The developed procedure was applied to three typical equipotential bonding materials: expanded copper foil (ECF), biaxial (BIAX) CFRP, and unidirectional (UD) CFRP. Both ECF and BIAX CFRP showed superior contact quality than the UD CFRP, with one to two orders of magnitude smaller contact resistivity.

Different conductive bonding strategies for the hybrid integration of flexible, inkjet-printed electronics are investigated. The focus of the present work lies on providing a practical guide comprising standard techniques that are inexpensive, easily implementable and frequently used. A sample set consisting of identical conductive test structures on different paper and plastic substrates was prepared using silver (Ag) nanoparticle ink. The sintered specimens were electrically contacted using soldering, adhesive bonding and crimping. Electrical and mechanical characterization before and after exposing the samples to harsh environmental conditions was performed to evaluate the reliability of the bonding methods. Resistance measurements were done before and after connecting the specimens. Afterwards, 85 &deg, C/85% damp-heat tests and tensile tests were applied. Adhesive bonding appears to be the most suitable and versatile method, as it shows adequate stability on all specimen substrates, especially after exposure to a 85 &deg, C/85% damp-heat test. During exposure to mechanical tensile testing, adhesive bonding proved to be the most stable, and forces up to 12 N could be exerted until breakage of the connection. As a drawback, adhesive bonding showed the highest increase in electrical resistance among the different bonding strategies.

This article analyzes the lightning transients in a commercial building with a grid like structure. The simulation is performed by using the partial element equivalent circuit method. Both the skin effect of the conductors and the nonlinear protection devices are taken into consideration. The induced voltage and the current sharing in the wiring system of both rising main circuit and secondary circuit are discussed. The influence of soil resistivity, lightning current waveform, different surge protection devices (SPDs) installations, and equipotential bonding are analyzed in this article. According to the simulation results, the soil resistivity can largely influence the potential of the conductor; however, it has a limited influence on the voltage between electric wires (potential difference). The SPDs installation arrangement and the equipotential bonding position in the building can greatly influence the lightning transients. The overvoltage and current can largely reduce if they are installed at a proper position. The suggestions provided in this article are constructive while designing the lightning protection system in buildings.

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 facades. 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 facade, 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.

Equipotential bonding, whereby objects are connected to a common electrical potential (usually ground) to prevent electrostatic discharges during material handling, has been shown to increase the risk of field-induced reticle damage. It is explained how the presence of an electric field can cause electrostatic damage in a reticle without a discharge event taking place. A comparison is drawn between the damage mechanisms that can take place in reticles and in semiconductor devices. The use of equipotential bonding during the manufacture of electrically sensitive semiconductor and micro-electro-mechanical systems is discussed. It is concluded that while equipotential bonding eliminates the risk of ESD during material handling, it simultaneously creates other risks for the devices being manufactured, which has the potential to introduce latent defects. An alternative methodology for dealing with electrostatic risk in semiconductor manufacturing is proposed, which would eliminate the undesirable enhancement of field-induction effects that is a consequence of using equipotential bonding.

The lightning protection and the surge protection of large ground-mounted photovoltaic power plants as well as of small roof-mounted photovoltaic systems is considered. Basics for external and internal lightning protection as well as special requirements, especially for surge protection, are presented. The measures result from experiences in the last years, are today recognized widely and are realized to a large extent. Lightning and surge protection of wind turbines has received increasing attention in recent decades due to considerable damage caused by direct lightning strikes. Today, onshore and offshore wind turbines are equipped with lightning protection systems according to the highest level of lightning protection and the declining damage shows the effectiveness of the measures. Special attention is paid to the protection of the rotor blades. But also surge protection for electrical energy and information technology systems including EMC measures is of great importance and is described. Many specialities have to be taken into account in the lightning and surge protection of wind turbines. For railway facilities and systems, national and international comprehensive concepts for lightning and surge protection have hardly been described. The considerations and measures presented here also do not claim to be complete, but are intended to address important aspects. These include above all measures for the protection of control and command technology systems as well as information on personal protection. In addition, lightning and surge protection of the power supply, measurement systems and EMC measures are addressed.

This paper presents a novel numerical approach to simulate lightning strike damage to equipotential bonding interfaces of wind turbine blades, and model validation based on high-current testing. Modern rotor blades are equipped with metal receptors to intercept the lightning leader and metal down conductors to conduct the lightning current, preventing the direct attachment to the CFRP spars. In such conditions, damage in the form of resin thermal degradation and sparks develop inside the blade at the equipotential bonding interfaces. Excellent correlation was found between the numerical predictions and test results in terms of current and temperature distributions. High temperatures were predicted at the sparking areas observed in the tests, which suggested that the damage is thermally activated. Thermogravimetric analysis data indicated that the epoxy pyrolysis process evolves in stages, and that sparking events are often initiated by release of gases and formation of small voids at temperatures lower than expected.

The electrical safety in workplace should always be fault-proof in all aspects. In power transmission network, some power companies follow a practice to permanently isolate the ground wire of transmission line from the substation ground grid. This paper discusses on how the practice is risking the worker, when carrying de-energized works on a transmission line (both single circuit and double circuit), and ways to minimize the transfer of substation ground potential that rises during fault to worksite, thereby ensures the safety during the work on transmission line.

Three-dimensional optical and electrical I/O structures for chip-scale Si photonic optical transceivers have been developed. The optical I/O structure, which is called an “optical pin,” has a vertical polymer waveguide structure. The waveguide structure has 125- $\mu$ m-pitch 8°-tilted cores. The tilted cores were formed by oblique-illuminated exposure. The electrical I/O structure comprises 250- $\mu$ m-pitch regularly-arranged through-glass-vias. As these I/O structures are configured on the same side of the Si photonic module, the configuration enables simultaneous optical and electrical bonding to a polymer-waveguide-embedded printed circuit board. The developed I/O structures minimize the packaging area and support 25-Gbps multimode transmission.

This paper presents a study on the overvoltages that appear between the conductive parts of a structure and its Lightning Protection System (LPS) when it 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 an interconnected steelwork and the voltages are computed for standard waveforms corresponding to negative first and subsequent strokes. The likelihood of insulation breakdown is assessed by the disruptive effect method, with conservative criteria that take into account oscillatory voltage waveforms. It is shown that sparks between LPS and structure steelwork are likely to occur, both for first and subsequent strokes, even if the separation distance as prescribed by the international standard is observed. The results also show that bonding the LPS to the steelwork at the top of the structure prevents such sparks for the considered conditions: structure height up to 60 m and Lightning Protection Level (LPL) III/IV. The paper also discusses how this subject is addressed in the international standard on protection against lightning.

The present paper has as main approach a performance study of a Lightning Protection System (LPS) as a function of the different conditions of the protection levels predicted on the IEC 62305, in effect today. Also based on a bibliographic research, a study of the implementation of an LPS in a real building was carried out. From the data of this installation, the modelling and simulations were performed in ATPDraw for the various risk classification conditions. The results of the simulations confirm that the higher the level of the protection, the lower are the currents in the down conductors systems and the lower are the voltages between the down conductors and the grounded points inside the installations.

This study aims to characterize the contact resistance of several equipotential bonding interfaces between the Carbon Fibre Reinforced Polymer (CFRP) spar and the Lightning Protection System (LPS). The total resistance of the coupons is measured, and the contact resistance is computed using the Finite Element Method (FEM). The latter is necessary to predict the resistance of CFRP components, which is not a trivial task because of the strong anisotropic nature of such materials. The developed methodology has been applied to a range of bonding materials: Expanded Copper Foil (ECF), Biaxial (Biax) CFRP and Unidirectional (UD) CFRP. It allows to propose the most reliable solutions for equipotential bonding applications.

Power-plants are sometimes built on massive bedrock with high soil resistivity thereby often resulting in less favorable grounding conditions. While grounding for applications with power system frequency can be achieved with large electrode areas, lightning strokes usually affect smaller areas with heavier impact. As a consequence a grounding system suitable for power system frequency is not necessarily capable of handling transient phenomena sufficiently well. A critical case is the ground potential rise when a large lightning surge propagates through the grounding system. The potential differences in different parts of grounding system may damage the connected wiring and equipment, depending on how grounding connections are made. New installations can be equipped with proper equipment but existing plants, especially those subject to detailed approval processes such as nuclear power-plants, often can't be modified easily. This paper evaluates the impact of lightning on a grounding system with different lightning surge propagation properties and finally presents a variety of solutions how to properly improve the transient protection for control equipment from a system point of view.

Touchable parts of electrical products and equipment can be thermally hot. Unintentional contact with hot surfaces during the normal operations of products may cause burns, and severity depends on the thermal resistivity of the material of the exposed part, the contact duration, the contact pressure, and skin conditions (i.e., dry, water wet, etc.). Currents flowing through equipment surfaces due to intentional choice or wiring errors can also elevate their temperatures, compounding the thermal effect; this causes an increased risk of triggering explosive atmospheres and fires in locations where combustible/flammable materials are processed or stored. In this paper, in light of applicable technical standards, the authors discuss and propose applicable burn thresholds, and permissible contact times with hot parts, based on different groups of users who may unintentionally touch the surfaces. The risk assessment of burning can be performed by comparing actual maximum temperatures of parts of electrical equipment against safe temperatures that a person may withstand for a given time without suffering a second degree burn.

This paper deals with those measures against overvoltage taken when protecting buildings occupied by people or animals. Such overvoltages can appear in the case of ground fault if the grounding system of the building is located within a potential funnel of a transmission tower's grounding system. This paper presents an entire concept regarding protection against any potential rise within the building. Computations of electrical potential on the grounding system having been performed using data obtained by measurements. This includes equipotential bonding, overvoltage protection of the building, and a transformer substation with metal–oxide varistors and gas-discharge arresters installed on the low-voltage line. A simulation model for the entire overvoltage protection based on known mathematical models has been merged within this paper. Adequate overvoltage protection elements were selected for protection against potential rises in the grounding systems of buildings on the basis of computation results.

Main objective of this paper is to evaluate the maximum partial lightning currents, which enter a building on electric installation lines. The conductors of the installation lines are equipotentially bonded to the air-termination or downconductor system at roof level. For live conductors, the lightning equipotential bonding is realized by the use of surge protective devices (SPD) which have towithstand the threat of the partial 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 facades. If the building is additionallyequipped with a metal roof, or, if the roof, the ceilings and the pillars/walls consist of concrete with steel reinforcement, the maximum expected charge is 0.1 C. For buildings without shielding elements (metal roof, metal facade, reinforced concrete), the charge is much higher, in the range of several coulombs. The values only apply to building up to heights of about 15 m using copper, aluminum or steel for the air-termination and down-conductor system. The transferred charge is significantly higher, if the air-termination and downconductor system consists of stainless steel.

In order to determine the safety distance required for live working of UHV DC transmission lines by helicopter hanging basket, the tests were carried out and analyzed in this paper. Firstly, based on the characteristics of the arrangement of poles and lines of UHV DC transmission lines, the helicopter basket method of entering and exiting equipotential bonding between the lines was analyzed. Then, the minimum safety distance test, when the basket is in a typical working position during live working, and different combinations test of gap distances are carried out. The minimum safety distance and the minimum combined gap distance required for live working of the helicopter basket method are determined. The minimum safety distance for the live working of the helicopter is given, which provides experimental evidence for the development and promotion of helicopter live working.

The main objective of this paper is to evaluate the maximum share of the lightning current, which flows on electric installations inside of buildings. The electrical conductors are equipotentially bonded to the external lightning protection system (LPS) at the roof level. A variety of wiring in typical buildings is analyzed using the computer code CONCEPT II. The transferred charge is the most important parameter for the selection of the surge protective devices (SPD). For a single conductor of an electrical line, the transferred charge is up to 0.6 C for buildings with metal facades. If the building is additionally equipped with a metal roof, the charge is reduced to less than 0.1 C. For (large) industrial buildings with steel reinforcement in the roof and in the ceilings, the charge is also very low, typically less than 0.1 C. In contrast, for houses without shielding elements such as metal facade, metal roof or reinforced concrete ceiling, the charge is relatively high, in the range of several coulombs. These results were obtained using copper or aluminum as materials for the external LPS. The use of normal steel increases the charge slightly. On the other hand, the use of stainless steel increases the charge to a higher extent due to the poor conductivity of stainless steel.

Wind turbines are more and more often erected in remote areas of the world, in order to exploit better wind conditions. In these areas the cost of failures and repairs can be substantial. For this reason ensuring the lightning performance of the turbines and especially of the blades has become very important.Modern blades are to a large extent manufactured using Carbon Fiber Composite (CFC) structural parts, due to the CFC’s excellent mechanical tensile strength and stiffness, combined with a light weight. However, Carbon Fiber Composites also exhibit highly anisotropic electric conductivities, which require special attention in terms of lightning protection, primarily in what concerns electrical bonding. The present paper presents the latest findings on how to include CFC materials in wind turbine blades into the lightning protection coordination, both in terms of engineering analysis using modern numerical tools, as well as with experimental validation in the lightning test facility. The paper is part of the EU funded project SPARCARB which started January 1st 2015 and which aims at exploring the details of lightning interactions with CFC materials, damage mechanisms, optimization of electrical/thermal properties by adjusting the chemical composition of resin, fiber sizing, weaving techniques, manufacturing processes, etc.

This paper discusses fundamental electrical safety issues, and the protection against electric shock of persons interacting with electric vehicles. The safety of users may be challenged by the vehicle's increased operating voltages, at different frequencies, possibly making more complex the protection against direct and indirect contacts. The electric safety of the vehicle is herein examined in both normal operating conditions, and in the case of electrical and/or mechanical failures; safety during charging is also examined. Solutions to improve safety are proposed, also in light of the evolution of the technology, and of applicable technical standards.

International (IEC) European (CENELEC) and American (NEC) Standards require, in each building, the connection of extraneous conductive parts (i.e. metal water or gas pipes) to the main grounding terminal. There are two good reasons for this: the voltage between extraneous conductive parts and exposed conductive parts is zeroed and extraneous conductive parts can contribute to the leakage of fault current into the ground. There is however a third advantage in the bonding connection: the entire structure (floors and walls of the building), together with the exposed and the extraneous metallic parts, forms a quasi-equipotential system, with the consequent strong reduction of touch voltages. Metallic pipes and reinforcement of reinforced concrete have a particular relevance thanks to their large widespread through buildings. However, in some practical cases, it is not possible to connect all extraneous conductive parts to the protective equipotential bonding because they are not accessible. In the paper, the reduction of touch voltages in buildings, when these extraneous conductive parts are present but not connected to the protective equipotential bonding is quantified. Different building models are created and solved by the finite element method in order to calculate touch voltages in different scenarios. The results show that the mere presence of widespread metallic parts in buildings helps to reduce touch voltages, but not enough to ensure safety against indirect contacts. The electrical installation safety performance is greatly improved in reinforced concrete buildings if at least some easily accessible parts, like water or central heating pipes, are connected to the main grounding terminal. Also in brick buildings, they provide a certain reduction of GPR, maximum and mean touch voltages.

In this paper, designing of an earthing system in accordance with international standards with regard to 22.9kV-y multi-grounded neutral system is discussed and confirmed that the consumer`s earthing system can be a part of a global earthing system by interconnecting its earthing system with the neutral conductor of 22.9kV-y multi-grounded system. Further, it is proposed that some modification of the earthing system design flowchart given in the international standards are necessary when considering the equipotential bonding, lightning protection, and telecommunications facilities as well as the basic safety requirements.

Construction of large and medium-sized program-controlled switches be placed strictly in accordance with national standards Professional program-controlled switchboard in the room, general will not be affected by lightning overvoltage and harm of operating over voltage. And small PABX are commonly used for smaller enterprises and institutions, such enterprises are unlikely to build professional for program-controlled switchboard room. Mostly I placed it on the corner of the Office or the Office area, convenient pin-outs. As a result of this device is undersized and lower prices, lightning protection concepts and enterprises and institutions to understand enough, it will not attach too much importance to. During the thunderstorm-prone season often makes their lightning overvoltage damage, direct economic loss was not too large, but the indirect economic losses are direct losses many times. This article in view of the characteristics of this equipment, according to the wiring form of power supply system using proper surge protection devices, equipotential bonding, shielding and grounding, and other combinations of several methods, and do not put too much financial and material resources to avoid accidents from happening, the various types of losses to a minimum.

By analyzing the two lightning accidents happening to a 500kV substation situated in the lightning-prone northeastern Guangdong Province, I conclude as follows, there should be some problem in the equipotential earthing of the secondary system of this substation. Specifically, the existing potential difference in the secondary equipment gave rise to the meltdown of it which finally caused the accident. In the context,I build the one-point earthing parallel system simulation model according to ATP graphic pretreatment program, then by using slope-ramp simulation I study the lightning current which leaked into the grounding grids of the substation.In conclusion, the application of high frequency signal mixed low frequency signal earth system in the secondary system and the equipotential bonding is key to preventing accidents.

Carbon fibre reinforced polymers (CFRP) are increasingly used for structures on aircraft due to their superior mechanical properties compared to traditional materials, such as aluminium. Additionally, in order to improve aircraft performance, there is a continued trend for electrically driven loads on aircraft, increasing the on-board electrical power generation capacity and complexity of the electrical power system, including a desire to increase voltage levels and move towards DC distribution systems. Central to the reliable operation of an electrical power system is the development of an appropriate protection and fault management strategy. If an electrical earth fault occurs on a composite more-electric aircraft then the CFRP may form part of the route to ground. In order to develop an appropriate protection system and thus to understand the effects on engine generators it is necessary to investigate the fault response of this network. Hence a suitable electrical model of the CFRP material is required, which will enable CFRP to be included in a computationally-intensive systems-level simulation study of a more-electric aircraft (MEA) with fully switching power electronic converter models. This paper presents an experimentally validated impedance model of CFRP at an appropriate level of fidelity for use in systems level simulation platforms, enabling appropriate protection methods to be developed. The validated model considers the impact of the electrical bonding to ground, including the impedance added by a metallic frame that a CFRP panel may be mounted in. The simplicity of the model results in a less complex process to determine the expected impedance of the CFRP material, enabling a focus on the fault response of the system and subsequent development of appropriate protection solutions.

Stray current corrosion phenomena of ductile iron pipe (DIP) located in the vicinity of cathodically protected steel pipe was assessed using the boundary element method. When all joints in DIP were electrically connected, the maximum corrosion rate was 0.005 mm/y. However, when the joints were isolated, the corrosion rate increased due to the jumping effect of stray current at isolated joints, which resulted in the increase of maximum corrosion rate to 0.87 mm/y at the isolated point. Moreover, the electrical bonding between the DIP and steel pipe could not act effectively but showed an adverse effect of collecting more cathodic protection (CP) currents into the DIP, which eventually jumped out into the soil and resulted in larger amount of stray current corrosion. Therefore it is desirable to apply control methods from the design and construction stage, which include the increase of anodebed and the pipe distance, electrical connection of DIP joints, installation of sacrificial anode at isolated joints, or the application of CP on DIP, etc.

An ordinary life area has numerous structures, systems, buildings, objects and components that are susceptible to lightning strikes. The effects of strikes can include actuation of safety systems, and loss of living areas. Protection of critical structures and applying necessary protection measures should be determined in terms of risk, completely risk management. The paper deals with results of investigation on efficiency of internal protection. The attention has been paid to the efficiency of the shields and to their kinds, arrangement, equipotential bonding and grounding according to the concept of lightning protection zones (LPZ).

This paper presents a study of lightning induced surges in railway signaling systems with the FDTD method. During an indirect lightning strike, induced surges are observed in the outdoor circuits due to electric and magnetic coupling. The induced surge currents propagate along the signal cables towards the receiving equipment in railway stations. It is found that geometry of the outdoor lines, earthing and bonding practices affect induced surge currents and voltages in the circuits. Equipotential bonding can substantially reduce the induced surge voltage impinging on the equipment in railway stations.

Asymmetric building structures force to build the earthing arrangements, the armouring of the building and the equipotential bonding system to be asymmetric as well. Another reason of asymmetries in earthing and equipotential bonding arrangements in symmetric building structures is the unawareness of planners and construction workers. As a consequence the building's electromagnetic compatibility (EMC) characteristic is influenced negatively and problems (such as interferences, failures or errors) when using sensitive electronic devices can occur. Both the ohmic and the inductive interference can be recognized as stray-currents in the PEN and PE conductors as well as in the earthing arrangement and the equipotential bonding system. As these currents are concentrated in the asymmetric zones, borderlines of buildings (armouring) and the PE/PEN/EB system they cause there relevant electromagnetic fields. The coupling of currents into the building installation can be caused by the external fields of high-voltage or railway facilities, by the fields of current-carrying low-voltage cables inside the building, by the asymmetric load of facilities (back current over PEN and EB conductors and building armouring). If the building structure is symmetric, both the currents and the fields extinguish in the ideal case or at least can be held low. In the contrary, the case of having an asymmetric building structure the external electromagnetic fields or the stray-currents can be amplified. The task of the EMC is to protect facilities against electromagnetic fields according to the limits which are specified in the actual standards. Since the fields in buildings are generally low, in this article low-frequency interfering fields are dealt with, which can interfere with sensitive equipment (i.e. in a hospital). Electromagnetic fields in the low-frequency range are the aim of the article (16.7 Hz or 50 Hz).

The paper introduces lightning protection for electric vehicle charging infrastructure. It analyzes causes of lightning damage and introduces overall protection solution for electric vehicle charging infrastructure, including protection against direct lightning, earthing system, equipotential bonding, shielding, routing and installation of SPDs.

Buried pipelines carrying hazardous products are mandated to be protected against corrosion, generally via layer(s) of coating materials integrated with active cathodic protection systems. Impressed-current systems, normally adopted for larger or longer structures, force the pipeline to behave as a cathode, therefore providing protection against corrosion of its exposed parts when the coating fails. Cathodically protected pipelines may, however, be buried in proximity of grounding electrodes, such as ground grids of substations; thus, they may need to be bonded to the grid to prevent, or lower, the risk of metal-to-metal touch voltages, as indicated in applicable technical standards. This bonding connection, required for the safety of the electrical operators, may, however, compromise the effectiveness of the cathodic protection, as well safety. In this paper, the authors explore the issues introduced by the coexistence of grounding systems and cathodic protection systems, and propose possible solutions to insure safety and, at the same time, protect assets and the environment from corrosion.

This paper describes the verification test on Electromagnetic Environmental Effects(E3), which conducted on ground as a final step to confirm the normal operation of ELINT pod and Safety-of-Flight of KF-16C/D mounted with ELINT pod prior to the initial flight. Based on MIL-STD-464A, indispensable 7 requirements among 14 detailed requirements total were carried out in the test. Considering the Safety-of-Flight(SOF), we invest a great deal of time and effort on Hazards of Electromagnetic Radiation to Ordnance(HERO) and Intra-system EMC test. E3 test and evaluation were performed on 62 equipments of KF-16C/D, respectively. As a result, we verify that KF-16C/D mounted with ELINT pod(hereafter "system") are electromagnetically compatible among all subsystems and equipment within the system and with environments caused by electromagnetic effects external to the system.

This paper provides comprehensive analysis on the lightning protection scenarios in 48 communication and broadcasting towers situated in similar isokeraunic contours in Sri Lanka at 79°–81° East and 5°–10° North. The investigation has been conducted to study the hazardous environment created on the tower and in the neighbourhood in the event of a lightning strike to the tower. The results show that a direct strike to an antenna structure in a metallic tower is rare irrespective of the presence of an air-termination or a down conductor. However, side flashing or arcing to antenna structures is highly possible once the air-termination and/or down conductor is installed and attempts are made to insulate the system from the tower. The outcome also shows that equipotential bonding of the grounding system, a distributed grounding network including a ring conductor and a suitable system of surge protective devices play a much vital role in lightning protection of equipment and safety of people compared to the effects of simply achieving a low grounding resistance. However, in the absence of such integrated, distributed and equipotentialized grounding system, a high value of ground resistance will sharply increase the possibility of accidents and damage. Considering the observations of the investigations into account we have designed a concrete embedded grounding system for tower sites at problematic locations. Finally, the scenarios for safety management at telecommunication tower sites have been discussed.

Antennas, if present on roofs, are, usually, the most prominent part of edifices. Grounding their metal supports is, generally, considered an effective means of protection of the structure against the effects of lightning strokes, eventually “attracted” by the antennas themselves. The antenna's mast and the down conductor are incorrectly assumed capable of safely draining to ground the lightning current flowing at the point of strike. This, supposedly, would prevent both hazard for people and damage to the building and electrical equipment situated inside of it. This paper will substantiate how the sole grounding of the antenna's mast can instead result in lowering the safety of the edifice, and, thereby, expose users to the hazard of dangerous electrical sparking (flashover) and possible fires.

This paper explains how an electric field and a reticle interact and describes the different kinds of damage that can be caused to a reticle through its exposure to electric field. It is shown why electrostatic reticle damage has changed from ESD damage (which causes yield to suddenly drop precipitously) into a gradual and cumulative form of degradation that is very difficult to diagnose. It is explained why some of the approaches that have been taken to reduce ESD damage in the semiconductor factory, such as equipotential bonding and the use of static dissipative plastics for making reticle pods, actually increase the risk of this cumulative type of electrostatic degradation in reticles. When assessing the risk to reticles and designing an effective protective strategy for reticle handling, it is shown why one must take into account the temporal characteristics of a reticle’s interaction with electric field—including the effect that the reticle’s immediate surroundings will have on that interaction—as well as considering the strength of any electric field in the reticle handling environment. Solutions are presented that would allow the electrostatic risk to reticles to be reduced significantly, without requiring major changes to operating procedures in semiconductor manufacturing facilities.

This paper deals with investigation on the spot for grounding systems of buildings based on international standards at construction sites. The investigation was carried out for grounding method, grounding type, shape of grounding electrode, grounding for a lightning protection system, continuity of steelwork in reinforced concrete structures, etc. The investigation on the spot was performed by a researcher and engineer with over fifteen years of industry experience all over the country. As a result of the investigation on the spot in 13 buildings, common grounding and structure grounding methods were dominant. The safety improvement methods include installation of equipotential bonding conductors for the connection to the main earthing terminal, equipotential bonding conductors for supplementary bonding, use of Surge Protective Devices (SPD), and safe connections between earthing conductors and the rebar.

This paper presents experimental results on the safety of persons and protection of low-voltage equipments of the sub-station due to a single-phase ground fault in 22.9 kV-Y distribution system. In order to evaluate the hazard voltages and the stress voltage of the low-voltage(LV) equipment due to faults between high-voltage systems and earth based on the newly prescribed KS C IEC 60364 standard series, the verification tests in a 22.9[kV] neutral multiple grounding system were carried out. From the experimental results, we introduce serious problems causing some discomfort when applying KS C IEC 60364 standard series to the existing domestic distribution system and the effective protective measures against temporary overvoltages due to a ground fault in the common grounding which is combined the 22.9 kV-Y grounding and the customer`s installation grounding are proposed. As a consequence, it was found that the equipotential bonding is an important prerequisite for the effectiveness of the protective measures for the safety of persons and LV equipment in the combined 22.9 kV-Y and low-voltage grounding system.

This paper presents the electric shock hazards and solutions of loss of the combined protective and neutral (PEN) conductor in TN-C-S system. In order to mitigate the touch voltage on exposed-conductive-parts in a break in the PEN conductor, the touch voltages on exposed-conductive-parts in a break in the PEN conductor were experimentally investigated as a function of the ground resistances of the source grounding electrode and customer`s additional grounding electrode. As a result, the equipotential bonding is one of important requirements for installations supplied by TN-C-S system. A solution of mitigating the touch voltages on exposed-conductor-parts caused by a loss of the PEN conductor would be the installation of the additional grounding electrode at the customer`s service entrance. The ground resistance of additional grounding electrode necessary to limit the touch voltage to a safety voltage of less than 50[V] depends on the load and circuit parameters. In addition, the undervoltage sensing devices oner affordable solutions to detect a loss of the PEN conductor in TN-C-S system.

The transient behavior of a cable, such as a communication line, entering a building subjected to a lightning stroke is investigated using the electromagnetic field theory approach. The field theory method used is essentially an extension of antenna theory to low frequencies. The computation of transient voltages is carried out using the MultiFields software package. The article focuses on the transient induced voltages at the boundary of two different lightning protection zones as required by the IEC 62305-3 standard. The main objective is to provide a computational analysis for the Surge Protection Device (SPD) implementation regarding the lightning equipotential bonding. Induced voltages are computed as well as the electric field in the air gap between the cable and the reinforcement rebar. SPDs and air break down voltages cause-effects are discussed briefly. Influences of several parameters are studied. Different waveforms with various peak values of current surges are examined. In this paper, authors demonstrate the importance of some parameters on the analysis of the transient ground potential rises to the lightning stroke for sparking risks prevention. Time domain results are shown as static 2D plots.

On top of major improvements in propulsion technology and in aerodynamics, step changes of the airframe structure efficiency are seen as key contributions in order to achieve the ambitious goals of next generation air transport vehicles. Efforts concentrate on manufacturing cost reduction as well as on performance improvement by function integration. State-of-the art composite airframe structures offer a poor electrical conductivity compared to metal and the mass to structural performance ratio is negatively impacted by additional elements needed to fulfill all required electrical functions for system integration (lightning strike, shielding of electric cables and systems, electrical bonding and grounding). Integrating the electrical function into the load-carrying function of the composite structures can reduce masses. A multifunctional composite material is investigated, consisting of carbon and high-strength metal fibers embedded in an epoxy matrix, with a focus on the evaluation of electrical properties as well as the mechanical properties and damage tolerance, as the metal fibers offer large strain for plastic deformation during impact events.

Recently an increase of sensor and power trandusers in control equipment system has caused many kinds of noise the mis-operation equipment and demage program memories of control circuits. In this paper, the noise character of the various control equipment system has been measured and analyzed. Additionally, the countermeasure to reduce noise like as Noise Cut Transformer, Equipotential Bonding, Power Noise Rejector, Noise Filter has been applied and confirmed the effective results to solve the trouble of noise.

Lightning current distribution in a directly hit building is studied by using a simple equivalent circuit and an electromagnetic model. The Numerical Electromagnetics Code (NEC-4) is employed for numerical electromagnetic analysis. The error in the shunt ratio of lightning current entering wiring, which is calculated using the electromagnetic model, is estimated to be less than 4%. The shunt ratios for lightning current entering the wiring on the top floor and the first floor are largest. Although they are larger for a higher building, they are almost constant if the building struck has more than five floors. They are smaller when there are more vertical conductors, or the length of the wiring is longer. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 159(1): 9–16, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20449

The lightning protection performance of the carbon fiber composite (CFC) main rotor blade of a helicopter is studied by using high-voltage large-current generators. According to the lightning zoning of this helicopter, the blade tip of the main rotor blade was considered belonging to lightning Zone 1A, the blade airfoil part and the blade root of main rotor blade were considered belonging to lightning Zone 2A. In order to achieve the lightning protection for the CFC blade, the blade tip part is protected by covering and bonding copper mesh, the blade leading edge is protected by fully wrapping and bonding metallic sheet wrap till the tip and grounding through a electrical bonding braid at the blade root. To assess the performance of the lightning protection design, simulated lightning strike testing (direct injecting of simulated lightning arc) were conducted for the blade tip part in Zone 1A and the blade airfoil part in Zone 2A, respectively. Coaxial return conductor arrangement which can minimize the magnetic field and magnetic force effect of the return current, and standardized lightning waveforms were employed in the lightning strike testing. Although multiple damages were found in the blade tip part, welded joints of the leading edge metallic wrap and other blade surfaces after the lighting arc injecting and current conducting testing, the mechanical structure integrity and it aerodynamics shape of the main rotor blade were not seriously affected, indicating that the lightning protection design of the main rotor blade is rational and advisable.

Cadmium plated circular connectors and chromate conversion coated aluminum chassis are widely used on electronic equipment for both civilian and military aerospace applications. This article discusses electrical bonding resistance problems associated with cadmium plated circular connectors and chromate conversion coated aluminum chassis and proposes an innovative way to solve that problem.Copyright © 2013 by ASME