Definite-time zero-sequence over-current protection is presently used in systems whose neutral point is grounded by a low resistance(low-resistance grounding systems).These systems frequently malfunction owing to thei...Definite-time zero-sequence over-current protection is presently used in systems whose neutral point is grounded by a low resistance(low-resistance grounding systems).These systems frequently malfunction owing to their high settings of the action value when a high-impedance grounding fault occurs.In this study,the relationship between the zero-sequence currents of each feeder and the neutral branch was analyzed.Then,a grounding protection method was proposed on the basis of the zero-sequence current ratio coefficient.It is defined as the ratio of the zero-sequence current of the feeder to that of the neutral branch.Nonetheless,both zero-sequence voltage and zero-sequence current are affected by the transition resistance,The influence of transition resistance can be eliminated by calculating this coefficient.Therefore,a method based on the zero-sequence current ratio coefficient was proposed considering the significant difference between the faulty feeder and healthy feeder.Furthermore,unbalanced current can be prevented by setting the starting current.PSCAD simulation results reveal that the proposed method shows high reliability and sensitivity when a high-resistance grounding fault occurs.展开更多
This paper discusses the characteristics of DC transmission common system ground electrode type and shared ground electrode, established the mathematical model of two circuit DC systems share ground electrode, analyze...This paper discusses the characteristics of DC transmission common system ground electrode type and shared ground electrode, established the mathematical model of two circuit DC systems share ground electrode, analyze effects of the shared loop ground DC transmission system electrode on the operation of HVDC system size under different operation modes, and compare with the independent ground electrode, ground electrode impact on environment under different operation mode, and the paper finally puts forward some solving measures for the influence of the shared ground electrode on the environment and public ground electrode effects on DC system operation problems.展开更多
Crane is currently more commonly used transportation equipment, playing an important role in many fields. However, the electrical equipment of the crane has a large capacity, so it is necessary to carry out protection...Crane is currently more commonly used transportation equipment, playing an important role in many fields. However, the electrical equipment of the crane has a large capacity, so it is necessary to carry out protection grounding test to reduce the probability of electric shock during the operation of the crane and ensure the safety of production. Therefore, it is necessary to carry out the inspection and testing of crane protection grounding circuit, crane protection external grounding connection and protective electrical device on the basis of understanding the structure of crane protection grounding system and the importance of crane protection grounding inspection and testing.展开更多
In recent years, with the development of economy, the development of Construction in China has also improved. With the rapid development of social economy and the reduction of urban construction land, it is inevitable...In recent years, with the development of economy, the development of Construction in China has also improved. With the rapid development of social economy and the reduction of urban construction land, it is inevitable that there will be a large number of skyscrapers, and a large number of electronic equipment will be installed during the construction. Because of the intelligent characteristics of the comprehensive building, its utilization rate is much higher than that of the traditional building. Therefore, the construction of electrical engineering and land protection requirements are higher. In order to minimize safety risks and create a good living and working environment for users, construction techniques must be strictly controlled during electronic installation and related installations must be properly managed. In addition, there is a need to protect the earth and improve the electrical safety of electromechanical equipment in high-rise buildings.展开更多
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
An electronic information system is composed of multiple groups of components. With the improvement of technology, its accuracy is getting higher and higher. The voltage during normal operation is only a few volts, an...An electronic information system is composed of multiple groups of components. With the improvement of technology, its accuracy is getting higher and higher. The voltage during normal operation is only a few volts, and the information current is only microamp, so the withstand voltage to lightning electromagnetic pulse is extremely low. In this paper, the negative impact of lightning and static electricity on the computer room of an electronic information system was analyzed firstly, and then the design for the lightning protection of the computer room was discussed.展开更多
In order to improve the quality of power supply and ensure the safe operation of the substation, the important role of lightning protection and grounding design of the substation is pointed out, and the causes of ligh...In order to improve the quality of power supply and ensure the safe operation of the substation, the important role of lightning protection and grounding design of the substation is pointed out, and the causes of lightning disaster of the substation are analyzed, i.e. lightning is introduced into the power line, lightning is introduced into the communication line and network line, the grounding is not standardized and the structure of the ground grid is problematic. The effective measures for lightning protection and grounding of substations are put forward, such as shielding lightning current accurately, installing lightning protection lightning receptor and lightning arrester of substations, and reasonably arranging lightning protection devices.展开更多
This is the new highest technology, 100% Venezuelan and unique in the world, technological innovation, world patent for maximum protection, security and zero risk （0） to all electrical and power generation systems：...This is the new highest technology, 100% Venezuelan and unique in the world, technological innovation, world patent for maximum protection, security and zero risk （0） to all electrical and power generation systems： hydroelectric and thermoelectric power plants, wind, nuclear and solar power plants, etc.; it is the only technology around the world that has the potential to disperse and propagate to land mass the enormous energies associated to the atmospheric discharges （lightning）, which are in the order： 200,000 to 500,000 Amperes; 1,000 million kilowatts and high-level transient voltage of 100 million volts. This new high technology is the solution to the paradigm of Benjamin Franklin and it is the mechanism to end ＂blackouts＂ that produces so many damages and losses of billions of dollars to both generators and users of electrical service, throughout the world.展开更多
Building intelligent weak current system contains a large number of electronic equipment, which generally has low insulation strength and poor voltage tolerance, and is easy to be damaged in case of lightning weather....Building intelligent weak current system contains a large number of electronic equipment, which generally has low insulation strength and poor voltage tolerance, and is easy to be damaged in case of lightning weather. In order to improve the safety and stability of building intelligent weak current system, this paper analyzes the lightning protection technology of intelligent weak current system.展开更多
基金supported in part by National Key Research and Development Program of China(2016YFB0900603)Technology Projects of State Grid Corporation of China(52094017000W).
文摘Definite-time zero-sequence over-current protection is presently used in systems whose neutral point is grounded by a low resistance(low-resistance grounding systems).These systems frequently malfunction owing to their high settings of the action value when a high-impedance grounding fault occurs.In this study,the relationship between the zero-sequence currents of each feeder and the neutral branch was analyzed.Then,a grounding protection method was proposed on the basis of the zero-sequence current ratio coefficient.It is defined as the ratio of the zero-sequence current of the feeder to that of the neutral branch.Nonetheless,both zero-sequence voltage and zero-sequence current are affected by the transition resistance,The influence of transition resistance can be eliminated by calculating this coefficient.Therefore,a method based on the zero-sequence current ratio coefficient was proposed considering the significant difference between the faulty feeder and healthy feeder.Furthermore,unbalanced current can be prevented by setting the starting current.PSCAD simulation results reveal that the proposed method shows high reliability and sensitivity when a high-resistance grounding fault occurs.
文摘This paper discusses the characteristics of DC transmission common system ground electrode type and shared ground electrode, established the mathematical model of two circuit DC systems share ground electrode, analyze effects of the shared loop ground DC transmission system electrode on the operation of HVDC system size under different operation modes, and compare with the independent ground electrode, ground electrode impact on environment under different operation mode, and the paper finally puts forward some solving measures for the influence of the shared ground electrode on the environment and public ground electrode effects on DC system operation problems.
文摘Crane is currently more commonly used transportation equipment, playing an important role in many fields. However, the electrical equipment of the crane has a large capacity, so it is necessary to carry out protection grounding test to reduce the probability of electric shock during the operation of the crane and ensure the safety of production. Therefore, it is necessary to carry out the inspection and testing of crane protection grounding circuit, crane protection external grounding connection and protective electrical device on the basis of understanding the structure of crane protection grounding system and the importance of crane protection grounding inspection and testing.
文摘In recent years, with the development of economy, the development of Construction in China has also improved. With the rapid development of social economy and the reduction of urban construction land, it is inevitable that there will be a large number of skyscrapers, and a large number of electronic equipment will be installed during the construction. Because of the intelligent characteristics of the comprehensive building, its utilization rate is much higher than that of the traditional building. Therefore, the construction of electrical engineering and land protection requirements are higher. In order to minimize safety risks and create a good living and working environment for users, construction techniques must be strictly controlled during electronic installation and related installations must be properly managed. In addition, there is a need to protect the earth and improve the electrical safety of electromechanical equipment in high-rise buildings.
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An electronic information system is composed of multiple groups of components. With the improvement of technology, its accuracy is getting higher and higher. The voltage during normal operation is only a few volts, and the information current is only microamp, so the withstand voltage to lightning electromagnetic pulse is extremely low. In this paper, the negative impact of lightning and static electricity on the computer room of an electronic information system was analyzed firstly, and then the design for the lightning protection of the computer room was discussed.
文摘In order to improve the quality of power supply and ensure the safe operation of the substation, the important role of lightning protection and grounding design of the substation is pointed out, and the causes of lightning disaster of the substation are analyzed, i.e. lightning is introduced into the power line, lightning is introduced into the communication line and network line, the grounding is not standardized and the structure of the ground grid is problematic. The effective measures for lightning protection and grounding of substations are put forward, such as shielding lightning current accurately, installing lightning protection lightning receptor and lightning arrester of substations, and reasonably arranging lightning protection devices.
文摘This is the new highest technology, 100% Venezuelan and unique in the world, technological innovation, world patent for maximum protection, security and zero risk （0） to all electrical and power generation systems： hydroelectric and thermoelectric power plants, wind, nuclear and solar power plants, etc.; it is the only technology around the world that has the potential to disperse and propagate to land mass the enormous energies associated to the atmospheric discharges （lightning）, which are in the order： 200,000 to 500,000 Amperes; 1,000 million kilowatts and high-level transient voltage of 100 million volts. This new high technology is the solution to the paradigm of Benjamin Franklin and it is the mechanism to end ＂blackouts＂ that produces so many damages and losses of billions of dollars to both generators and users of electrical service, throughout the world.
文摘Building intelligent weak current system contains a large number of electronic equipment, which generally has low insulation strength and poor voltage tolerance, and is easy to be damaged in case of lightning weather. In order to improve the safety and stability of building intelligent weak current system, this paper analyzes the lightning protection technology of intelligent weak current system.
