To better improve the electrical safety of buildings and fulfill the role of lightning protection and grounding,this article combines cases and discusses seven aspects of lightning protection devices’construction tec...To better improve the electrical safety of buildings and fulfill the role of lightning protection and grounding,this article combines cases and discusses seven aspects of lightning protection devices’construction technology.These aspects include the lightning protection classification of buildings,air terminals,down conductors,grounding devices,division of lightning protection zones,and lightning electromagnetic pulse shielding.Through the introduction of this article,readers can gain a comprehensive understanding of the application and value of lightning protection grounding construction technology in building electrical installation projects.展开更多
The role played by equipotential connection in lightning protection was summarized in terms of lightning protection,static electricity,electromagnetic shielding,protection from electric shocks,and earth fault protecti...The role played by equipotential connection in lightning protection was summarized in terms of lightning protection,static electricity,electromagnetic shielding,protection from electric shocks,and earth fault protection.In addition,drawbacks of independent grounding and common grounding were concluded.According to standards and researches,such as Building Lightning Protection Design Standard (GB50057-2010),further demands and rules of equipotential connection in lightning protection engineering were proposed,providing references for lightning prevention design,construction and examination by related scientific workers and staffs.展开更多
In order to improve the lightning protection performance of transmission lines, lightning protection management has been divided into every tower that lightning protection performance has been evaluated respectively. ...In order to improve the lightning protection performance of transmission lines, lightning protection management has been divided into every tower that lightning protection performance has been evaluated respectively. According to factors such as landform, span, tower type, grounding resistance, isolator type, and so on, relative ratio of tripping operation of every tower in the line has been calculated to evaluate its lightning protection safety performance, it is beneficial to operation maintenance and lightning reconstruction of transmission lines.展开更多
DCS (distributed control system) plays a decisive role in the overall operation of a nuclear power plant. If DCS fails, it will seriously affect the normal production of nuclear power plant, causing great losses. So...DCS (distributed control system) plays a decisive role in the overall operation of a nuclear power plant. If DCS fails, it will seriously affect the normal production of nuclear power plant, causing great losses. So it is very important to take perfect lightning protection measures on DCS of the nuclear power plant. In this paper, according to the actual situation of DCS in a nuclear power plant, by controlling lightning point, securely booting lightning into the ground network, improving low-resistance ground network, eliminating ground loops, determining the safety space, surge protection of power and signal, a set of complete lightning protection design scheme was systematically put forward. Some specific lightning protection measures were highlighted, such as the DCS grounding, equipotential bonds and shields, and some specific considerations were put forward. All of these could offer reference in the practical application.展开更多
In recent years,along with the rapid expansion of power grids,the increasing complication of grid structures,and the development of smart grids and energy technologies,the lightning protection of power grids becomes i...In recent years,along with the rapid expansion of power grids,the increasing complication of grid structures,and the development of smart grids and energy technologies,the lightning protection of power grids becomes increasingly prominent.Power grids of China have acquired significant achievements on lightning protection technologies,which are reviewed in this paper.A technical route of lightning protection is introduced in detail; it allows us to find problems through detection and measurement of lightning,to analyze problems through evaluation and simulation of lightning,to solve problems through lightning protection measures,and to prevent problems through hazard risk warning of lightning.Following the route,the technical breakthroughs of these four aspects in China are presented,including the chinese lightning detection network(CLDN),natural lightning observations,lightning faults detection at transmission lines,lightning current measurements,progresses in lightning distribution maps,lightning fault replays,lightning hazard risk evaluations,and lightning simulated experiments,as well as novel lightning protection measures.The practical devices and systems corresponding to the technologies mentioned above are also introduced and discussed.Due to the progress of lightning protection technologies in recent years,despite the rapidly growing length of transmission lines in China,the lightning accident rate is controlled at a certain level.展开更多
Taking lightning-protection engineering of Wuhan Changshankou landfill and incineration plants for the example,in this article,we have discussed the integrated technology of direct lightning protection by early stream...Taking lightning-protection engineering of Wuhan Changshankou landfill and incineration plants for the example,in this article,we have discussed the integrated technology of direct lightning protection by early streamer emission lightning rod,lifting lightning rod and mobile lightning rod. Additionally,lightning protection methods and measures of landfill with large receiving area of lightning strike and landfill gas and incineration plant with irregular landfill cell are explored.展开更多
Due to its large and metallic structure, large recreation facility is easy to be struck by lightning. Meanwhile, the lightning strike conse- quences are serious, including threat to the life and property safety of tou...Due to its large and metallic structure, large recreation facility is easy to be struck by lightning. Meanwhile, the lightning strike conse- quences are serious, including threat to the life and property safety of tourists, great impact on society and bad effect on the development of tourism. As a result, lightning protection of recreation facility is particularly important. Taking the Ferris wheel of Zijin Park as an example, its light- ning risk and structural characteristics were analyzed to make reasonable solving scheme. Through the study about lightning risks of recreational fa- cilities with different structures and geographical positions, the lightning protection differences between recreational facilities and the general lightning protection scheme were summarized.展开更多
Via database technology, a perfect lightning protection integrated service work platform is established, thereby realizing paperless data management of routine business.
There are two major protective methods against lightning outages on overhead distribution lines.One is a surge arrester,and the other is an overhead ground wire.The surge arresters have rather constant effect regardle...There are two major protective methods against lightning outages on overhead distribution lines.One is a surge arrester,and the other is an overhead ground wire.The surge arresters have rather constant effect regardless of the cause of the lightning outage.On the other hand,the effect of an overhead ground wire is quite different in two major causes,the direct lightning hit and the induced overvoltage.It is sufficient to provide surge arresters with an interval of 300 m for protection against the induced overvoltage caused by the nearby lightning stroke.Use of an overhead ground wire together with surge arresters is effective for lightning protection against the direct lightning hit to a distribution line.Puncture of surge arresters is the popular outage when the outage caused by the insulation break decreases sufficiently.Also,the existence of nearby trees leads to the line break due to the side flash from a tree.Advanced lightning protection equipment with ZnO arrester components is popular in Japan.Modeling of a pole transformer and application of an electromagnetic analysis method,such as FDTD method,to surge phenomena is considerably advanced.展开更多
Electric and magnetic fields generated by lightning cause a serious hazard to various systems.Now wind turbine installations with higher power capacity are increasing.Higher power capacity requires higher height and s...Electric and magnetic fields generated by lightning cause a serious hazard to various systems.Now wind turbine installations with higher power capacity are increasing.Higher power capacity requires higher height and so there is more probability of lightning strike.Blades are the most probable components to be struck by lightning.The most common lightning protection system for the blades consists of several metallic receptors on the blade surface.Those are connected to the ground by metallic down-conductors placed inside the blade shell.This paper studies effects of the receptor configurations on protecting the blade against lightning strike.For this purpose,an analysis procedure based on finite element method(FEM)in COMSOL Multiphysics software environment is used.The voltage distribution around the blade is simulated for various configurations of receptors.The best configuration is presented.Simulations are performed on the blade model of a special wind turbine,which isVESTAS V47".展开更多
In addition to the conventional Franklin Rod,many non-conventional air terminals are being used as lightning protection devices.As cited in previous works,these non-conventional devices emit space charge in the vicini...In addition to the conventional Franklin Rod,many non-conventional air terminals are being used as lightning protection devices.As cited in previous works,these non-conventional devices emit space charge in the vicinity of the terminals during the process of lightning stroke.A number of factors affect the performance of these lightning protection devices,among them are geometry and dimension of the devices,location of the device above the ground,height of the cloud above the ground,and polarity of the lightning stroke.The performance of these lightning protection devices has been a topic of discussion by researchers for many years.Some studies focused on the magnitude of emission current from these devices as a criterion to evaluate their performances.The critical flashover voltage(CFO)between the devices and a metal screen simulating cloud can also be used as another criterion to evaluate the performance of the devices.Laboratory measurements were conducted in controlled conditions on different types of lightning protection devices to compare their performance.Four different types of devices were used in the present study:Franklin Rod,TerraStat models TS 100,TS 400,and Spline Ball Ionizer.The study focused on the CFO voltage of the air gap between devices and the metal screen.The CFO voltage was evaluated using standard switching and lightning impulses.The measurements were recorded for positive as well as negative polarity.The air gap between the devices and metal screen was selected at 2 m and 3 m.The results obtained provide a better understanding of the electrical performance of lightning protection devices.展开更多
In this paper,lightning protection technical service of oil depot is taken as research object. It is proposed using various meteorological data to carry out multiple lightning protection technical services( risk asses...In this paper,lightning protection technical service of oil depot is taken as research object. It is proposed using various meteorological data to carry out multiple lightning protection technical services( risk assessment,potential forecast,monitoring and early warning of lightning disasters) based on conventional detection of lightning protection system,to improve technical content of lightning protection service and benefits of disaster prevention and mitigation. It mainly analyzes the application of lightning monitoring data in pre-assessment of lightning disaster,to guide site selection of new oil depot; guidance of lightning disaster status assessment on regular inspection of lightning protection system,to determine lightning protection detection time and update and maintenance time of lightning protection system; potential prediction and early warning of lightning,to guide daily operation of oil depot.展开更多
With the improvement of rural living conditions,there are more and more new houses in the countryside,but these new houses have very serious lightning hazard. In this paper,statistics situation of lightning disaster i...With the improvement of rural living conditions,there are more and more new houses in the countryside,but these new houses have very serious lightning hazard. In this paper,statistics situation of lightning disaster in Hebei Province is introduced firstly,and results show that total amount of lightning accident has a rising trend year by year in Hebei Province,especially in the countryside. Finally,making method for simple grounding of rural house is introduced,which could provide the reference for lightning protection of rural house in Hebei Province.展开更多
In the thunderstorm process on August 3,2016,among the nine elevators in a housing estate in the middle of Neijiang City,six elevators were damaged by lightning. In this study,the impact of lightning stroke on elevato...In the thunderstorm process on August 3,2016,among the nine elevators in a housing estate in the middle of Neijiang City,six elevators were damaged by lightning. In this study,the impact of lightning stroke on elevators was analyzed firstly,and then measures to protect elevators against lightning were proposed,which provides a practical basis for the improvement of protection of elevators against lightning.展开更多
The rail weighbridge system of a railway freight station is introduced firstly, and then the earthing method for protection of the rail weighbridge system against lightning based on YLG-60 equipotential bonding surge ...The rail weighbridge system of a railway freight station is introduced firstly, and then the earthing method for protection of the rail weighbridge system against lightning based on YLG-60 equipotential bonding surge protection device is shown.展开更多
In order to obtain reasonable schemes of arrester in converter stations, the arrester scheme of "Xiluodu-Guangdong HVDC ± 500 kV double circuit transmission" project against lighting induced overvoltage...In order to obtain reasonable schemes of arrester in converter stations, the arrester scheme of "Xiluodu-Guangdong HVDC ± 500 kV double circuit transmission" project against lighting induced overvoltage, which was designed according to the main principle of lightning protection in converter station, is discussed. A calculation of the lighting induced overvoltage in Zhaotong converter station un- der various operation modes is performed with ATP-EMTP software, then the surge arrester configuration of the converter station is decided, and the arrester protection schemes of smoothing reactor and neutral line are studied. It is concluded that additional protection is necessary because of the relatively large gap between protected disconnecting switch and arrester of metallic return transfer bus. Plus, the smoothing reactor (SR) arrester near the valve hall could be removed to improve the scheme’s economic performance.展开更多
An accurate determination of lightning protection zone is an important issue in the analysis and design of an appropri-ate lightning protection system. This paper presents a fast and accurate protection zone determina...An accurate determination of lightning protection zone is an important issue in the analysis and design of an appropri-ate lightning protection system. This paper presents a fast and accurate protection zone determination methodology for metallic lightning rod. The methodology is based on Quasi Monte Carlo Integration technique applied to Method of Moments (MoM) solution of Integral Equations. As an example, solution of the integral equation for unknown charge distribution on lightning rod is obtained. The electric field in the region surrounding the rod is then computed and the protection zone plotted accordingly. The effect of the thickness of the rod on the protection zone is also studied.展开更多
To resolve the impact of transient high frequency signals induced by lightning stroke on the travelling wave protection of transmission line, a novel identification algorithm is proposed. Using the characteristics of ...To resolve the impact of transient high frequency signals induced by lightning stroke on the travelling wave protection of transmission line, a novel identification algorithm is proposed. Using the characteristics of symmetric current wave-form induced by lightning stroke without causing fault and that of asymmetric current waveform generated by fault within a very short time interval, the waveform of transient current above and below time-axes are integrated respec-tively. First, through comparing the relative ratio of them with threshold value, the primary criterion identifying fault and lightning stroke is constructed;Secondly, to improve the reliability of discrimination between lightning stroke with and without causing fault, according to the difference of them, the secondary criterion is also defined. The simulation results and analysis demonstrate that the proposed integral criterions are valid and correct.展开更多
In order to inspect the good and reliability of automated charging station’s lightning protection design in airport, we set the comprehensive evaluation mathematical model of automated charging station in the airport...In order to inspect the good and reliability of automated charging station’s lightning protection design in airport, we set the comprehensive evaluation mathematical model of automated charging station in the airport, through the method of second order fuzzy comprehensive evaluation and evaluate the automated charging station’s lightning protection design comprehensively by using the assessment data of expert database.展开更多
This paper is devoted to the study of the most suitable protocols needed to verify the lightning protection and ground resistance quality in a large-scale scientific facility located on a site with high risk of lightn...This paper is devoted to the study of the most suitable protocols needed to verify the lightning protection and ground resistance quality in a large-scale scientific facility located on a site with high risk of lightning strikes. We illustrate this work by reviewing a case study: the largest telescopes of the Northern Hemisphere Cherenkov Telescope Array, CTA-N. This array hosts sensitive and high-speed optoelectronics instrumentation and sits on a clear, free from obstacle terrain at around 2400 m above sea level. The site offers a top-quality sky but also features challenging conditions for a lightning protection system: the terrain is volcanic and has electrical resistivities well above 1 kOhm·m. In addition, the environment often exhibits humidities well below 5%, and strong winds pose challenging conditions. On the other hand, the </span><span style="font-family:Verdana;">high complexity of a Cherenkov telescope structure does not allow a straightforward</span><span style="font-family:Verdana;"> application of lightning protection standards. We describe here how the risk assessment of direct strike impacts was made and how contact voltages and ground system were both tested. Finite Element Simulation (COMSOL Multiphysics) has been used to estimate the current flowing through the parts of the earthing system designed for the telescopes in the case of a direct strike impact. This work is intended to provide assistance to scientists and managers involved in the construction of scientific installations, particularly those in charge of defining verifiable reliability and safety requirements for lightning protection.展开更多
文摘To better improve the electrical safety of buildings and fulfill the role of lightning protection and grounding,this article combines cases and discusses seven aspects of lightning protection devices’construction technology.These aspects include the lightning protection classification of buildings,air terminals,down conductors,grounding devices,division of lightning protection zones,and lightning electromagnetic pulse shielding.Through the introduction of this article,readers can gain a comprehensive understanding of the application and value of lightning protection grounding construction technology in building electrical installation projects.
文摘The role played by equipotential connection in lightning protection was summarized in terms of lightning protection,static electricity,electromagnetic shielding,protection from electric shocks,and earth fault protection.In addition,drawbacks of independent grounding and common grounding were concluded.According to standards and researches,such as Building Lightning Protection Design Standard (GB50057-2010),further demands and rules of equipotential connection in lightning protection engineering were proposed,providing references for lightning prevention design,construction and examination by related scientific workers and staffs.
文摘In order to improve the lightning protection performance of transmission lines, lightning protection management has been divided into every tower that lightning protection performance has been evaluated respectively. According to factors such as landform, span, tower type, grounding resistance, isolator type, and so on, relative ratio of tripping operation of every tower in the line has been calculated to evaluate its lightning protection safety performance, it is beneficial to operation maintenance and lightning reconstruction of transmission lines.
基金Research Fund for Youth in Jiangsu Provincial Meteorological Bureau,China(Q201007)
文摘DCS (distributed control system) plays a decisive role in the overall operation of a nuclear power plant. If DCS fails, it will seriously affect the normal production of nuclear power plant, causing great losses. So it is very important to take perfect lightning protection measures on DCS of the nuclear power plant. In this paper, according to the actual situation of DCS in a nuclear power plant, by controlling lightning point, securely booting lightning into the ground network, improving low-resistance ground network, eliminating ground loops, determining the safety space, surge protection of power and signal, a set of complete lightning protection design scheme was systematically put forward. Some specific lightning protection measures were highlighted, such as the DCS grounding, equipotential bonds and shields, and some specific considerations were put forward. All of these could offer reference in the practical application.
基金Project supported by National Basic Research Program of China (973 Program) (2011CB209400), National Fligh-tech Research and Developmerit Program of China (863 Program (2011AA040405), National Natural Science Foundation of China (Ul134106), 3551 Optics Valley Personal Plan of Wuhan East Lake High-tech Development Zone, Science and Technology Program of SGCC(SG[2009], SG[2013]).
文摘In recent years,along with the rapid expansion of power grids,the increasing complication of grid structures,and the development of smart grids and energy technologies,the lightning protection of power grids becomes increasingly prominent.Power grids of China have acquired significant achievements on lightning protection technologies,which are reviewed in this paper.A technical route of lightning protection is introduced in detail; it allows us to find problems through detection and measurement of lightning,to analyze problems through evaluation and simulation of lightning,to solve problems through lightning protection measures,and to prevent problems through hazard risk warning of lightning.Following the route,the technical breakthroughs of these four aspects in China are presented,including the chinese lightning detection network(CLDN),natural lightning observations,lightning faults detection at transmission lines,lightning current measurements,progresses in lightning distribution maps,lightning fault replays,lightning hazard risk evaluations,and lightning simulated experiments,as well as novel lightning protection measures.The practical devices and systems corresponding to the technologies mentioned above are also introduced and discussed.Due to the progress of lightning protection technologies in recent years,despite the rapidly growing length of transmission lines in China,the lightning accident rate is controlled at a certain level.
文摘Taking lightning-protection engineering of Wuhan Changshankou landfill and incineration plants for the example,in this article,we have discussed the integrated technology of direct lightning protection by early streamer emission lightning rod,lifting lightning rod and mobile lightning rod. Additionally,lightning protection methods and measures of landfill with large receiving area of lightning strike and landfill gas and incineration plant with irregular landfill cell are explored.
基金Supported by Science Research Item of Changzhou Meteorological Bureau,China(1305)
文摘Due to its large and metallic structure, large recreation facility is easy to be struck by lightning. Meanwhile, the lightning strike conse- quences are serious, including threat to the life and property safety of tourists, great impact on society and bad effect on the development of tourism. As a result, lightning protection of recreation facility is particularly important. Taking the Ferris wheel of Zijin Park as an example, its light- ning risk and structural characteristics were analyzed to make reasonable solving scheme. Through the study about lightning risks of recreational fa- cilities with different structures and geographical positions, the lightning protection differences between recreational facilities and the general lightning protection scheme were summarized.
文摘Via database technology, a perfect lightning protection integrated service work platform is established, thereby realizing paperless data management of routine business.
文摘There are two major protective methods against lightning outages on overhead distribution lines.One is a surge arrester,and the other is an overhead ground wire.The surge arresters have rather constant effect regardless of the cause of the lightning outage.On the other hand,the effect of an overhead ground wire is quite different in two major causes,the direct lightning hit and the induced overvoltage.It is sufficient to provide surge arresters with an interval of 300 m for protection against the induced overvoltage caused by the nearby lightning stroke.Use of an overhead ground wire together with surge arresters is effective for lightning protection against the direct lightning hit to a distribution line.Puncture of surge arresters is the popular outage when the outage caused by the insulation break decreases sufficiently.Also,the existence of nearby trees leads to the line break due to the side flash from a tree.Advanced lightning protection equipment with ZnO arrester components is popular in Japan.Modeling of a pole transformer and application of an electromagnetic analysis method,such as FDTD method,to surge phenomena is considerably advanced.
文摘Electric and magnetic fields generated by lightning cause a serious hazard to various systems.Now wind turbine installations with higher power capacity are increasing.Higher power capacity requires higher height and so there is more probability of lightning strike.Blades are the most probable components to be struck by lightning.The most common lightning protection system for the blades consists of several metallic receptors on the blade surface.Those are connected to the ground by metallic down-conductors placed inside the blade shell.This paper studies effects of the receptor configurations on protecting the blade against lightning strike.For this purpose,an analysis procedure based on finite element method(FEM)in COMSOL Multiphysics software environment is used.The voltage distribution around the blade is simulated for various configurations of receptors.The best configuration is presented.Simulations are performed on the blade model of a special wind turbine,which isVESTAS V47".
文摘In addition to the conventional Franklin Rod,many non-conventional air terminals are being used as lightning protection devices.As cited in previous works,these non-conventional devices emit space charge in the vicinity of the terminals during the process of lightning stroke.A number of factors affect the performance of these lightning protection devices,among them are geometry and dimension of the devices,location of the device above the ground,height of the cloud above the ground,and polarity of the lightning stroke.The performance of these lightning protection devices has been a topic of discussion by researchers for many years.Some studies focused on the magnitude of emission current from these devices as a criterion to evaluate their performances.The critical flashover voltage(CFO)between the devices and a metal screen simulating cloud can also be used as another criterion to evaluate the performance of the devices.Laboratory measurements were conducted in controlled conditions on different types of lightning protection devices to compare their performance.Four different types of devices were used in the present study:Franklin Rod,TerraStat models TS 100,TS 400,and Spline Ball Ionizer.The study focused on the CFO voltage of the air gap between devices and the metal screen.The CFO voltage was evaluated using standard switching and lightning impulses.The measurements were recorded for positive as well as negative polarity.The air gap between the devices and metal screen was selected at 2 m and 3 m.The results obtained provide a better understanding of the electrical performance of lightning protection devices.
文摘In this paper,lightning protection technical service of oil depot is taken as research object. It is proposed using various meteorological data to carry out multiple lightning protection technical services( risk assessment,potential forecast,monitoring and early warning of lightning disasters) based on conventional detection of lightning protection system,to improve technical content of lightning protection service and benefits of disaster prevention and mitigation. It mainly analyzes the application of lightning monitoring data in pre-assessment of lightning disaster,to guide site selection of new oil depot; guidance of lightning disaster status assessment on regular inspection of lightning protection system,to determine lightning protection detection time and update and maintenance time of lightning protection system; potential prediction and early warning of lightning,to guide daily operation of oil depot.
文摘With the improvement of rural living conditions,there are more and more new houses in the countryside,but these new houses have very serious lightning hazard. In this paper,statistics situation of lightning disaster in Hebei Province is introduced firstly,and results show that total amount of lightning accident has a rising trend year by year in Hebei Province,especially in the countryside. Finally,making method for simple grounding of rural house is introduced,which could provide the reference for lightning protection of rural house in Hebei Province.
文摘In the thunderstorm process on August 3,2016,among the nine elevators in a housing estate in the middle of Neijiang City,six elevators were damaged by lightning. In this study,the impact of lightning stroke on elevators was analyzed firstly,and then measures to protect elevators against lightning were proposed,which provides a practical basis for the improvement of protection of elevators against lightning.
文摘The rail weighbridge system of a railway freight station is introduced firstly, and then the earthing method for protection of the rail weighbridge system against lightning based on YLG-60 equipotential bonding surge protection device is shown.
基金Project supported by Key Project of National Natural Science Foundation of China (50737003).
文摘In order to obtain reasonable schemes of arrester in converter stations, the arrester scheme of "Xiluodu-Guangdong HVDC ± 500 kV double circuit transmission" project against lighting induced overvoltage, which was designed according to the main principle of lightning protection in converter station, is discussed. A calculation of the lighting induced overvoltage in Zhaotong converter station un- der various operation modes is performed with ATP-EMTP software, then the surge arrester configuration of the converter station is decided, and the arrester protection schemes of smoothing reactor and neutral line are studied. It is concluded that additional protection is necessary because of the relatively large gap between protected disconnecting switch and arrester of metallic return transfer bus. Plus, the smoothing reactor (SR) arrester near the valve hall could be removed to improve the scheme’s economic performance.
文摘An accurate determination of lightning protection zone is an important issue in the analysis and design of an appropri-ate lightning protection system. This paper presents a fast and accurate protection zone determination methodology for metallic lightning rod. The methodology is based on Quasi Monte Carlo Integration technique applied to Method of Moments (MoM) solution of Integral Equations. As an example, solution of the integral equation for unknown charge distribution on lightning rod is obtained. The electric field in the region surrounding the rod is then computed and the protection zone plotted accordingly. The effect of the thickness of the rod on the protection zone is also studied.
文摘To resolve the impact of transient high frequency signals induced by lightning stroke on the travelling wave protection of transmission line, a novel identification algorithm is proposed. Using the characteristics of symmetric current wave-form induced by lightning stroke without causing fault and that of asymmetric current waveform generated by fault within a very short time interval, the waveform of transient current above and below time-axes are integrated respec-tively. First, through comparing the relative ratio of them with threshold value, the primary criterion identifying fault and lightning stroke is constructed;Secondly, to improve the reliability of discrimination between lightning stroke with and without causing fault, according to the difference of them, the secondary criterion is also defined. The simulation results and analysis demonstrate that the proposed integral criterions are valid and correct.
文摘In order to inspect the good and reliability of automated charging station’s lightning protection design in airport, we set the comprehensive evaluation mathematical model of automated charging station in the airport, through the method of second order fuzzy comprehensive evaluation and evaluate the automated charging station’s lightning protection design comprehensively by using the assessment data of expert database.
文摘This paper is devoted to the study of the most suitable protocols needed to verify the lightning protection and ground resistance quality in a large-scale scientific facility located on a site with high risk of lightning strikes. We illustrate this work by reviewing a case study: the largest telescopes of the Northern Hemisphere Cherenkov Telescope Array, CTA-N. This array hosts sensitive and high-speed optoelectronics instrumentation and sits on a clear, free from obstacle terrain at around 2400 m above sea level. The site offers a top-quality sky but also features challenging conditions for a lightning protection system: the terrain is volcanic and has electrical resistivities well above 1 kOhm·m. In addition, the environment often exhibits humidities well below 5%, and strong winds pose challenging conditions. On the other hand, the </span><span style="font-family:Verdana;">high complexity of a Cherenkov telescope structure does not allow a straightforward</span><span style="font-family:Verdana;"> application of lightning protection standards. We describe here how the risk assessment of direct strike impacts was made and how contact voltages and ground system were both tested. Finite Element Simulation (COMSOL Multiphysics) has been used to estimate the current flowing through the parts of the earthing system designed for the telescopes in the case of a direct strike impact. This work is intended to provide assistance to scientists and managers involved in the construction of scientific installations, particularly those in charge of defining verifiable reliability and safety requirements for lightning protection.