Single-phase 25 kV traction networks of electrified alternating current(AC)railways create electromagnetic fields(EMFs)with significant levels of intensity.The most intense magnetic fields occur when short circuits ex...Single-phase 25 kV traction networks of electrified alternating current(AC)railways create electromagnetic fields(EMFs)with significant levels of intensity.The most intense magnetic fields occur when short circuits exist between the contact wire and rails or ground.Despite the short duration of exposure,they can adversely affect electronic devices and induce significant voltages in adjacent power lines,which is dangerous for operating personnel.Although numerous investigations have focused on modeling the EMF of traction networks and power lines,the challenge of determining the three-dimensional electromagnetic fields near metal supports during the flow of a short-circuit current through them is yet to be resolved.In this case,the field has a complex spatial structure that significantly complicates the calculations of intensities.This study proposes a methodology,algorithms,software,and digital models for determining the EMF in the described emergency scenarios.During the modeling process,the objects being studied were represented by segments of thin wires to analyze the distribution of the electric charge and calculate the intensities of the electric and magnetic fields.This approach was implemented in the Fazonord software,and the modeling results show a substantial increase in EMF levels close to the support,with a noticeable decrease in the levels as the distance from it increases.The procedure implemented in the commercial software Fazonord is universal and can be used to determine electromagnetic fields at any electrical power facility that includes live parts of limited length.Based on the proposed procedure,the EMF near the supports of overhead power lines and traction networks of various designs could be determined,the EMF levels at substations can be calculated,and the influence of metal structures located near traction networks,such as pedestrian crossings at railway stations,can be considered.展开更多
电动助力转向(electric power steering,EPS)系统是车辆常用的转向执行器,其失效将严重影响驾乘人员的安全。为提高EPS系统的安全性与可靠性,基于功能安全标准建立EPS系统安全冗余机制:基于ISO26262对EPS系统进行研究,通过相关项定义、...电动助力转向(electric power steering,EPS)系统是车辆常用的转向执行器,其失效将严重影响驾乘人员的安全。为提高EPS系统的安全性与可靠性,基于功能安全标准建立EPS系统安全冗余机制:基于ISO26262对EPS系统进行研究,通过相关项定义、危害分析与风险评估(HARA),得到系统的功能安全目标与需求,并对其进行分配;设计EPS系统架构、容错机制,以提高系统的安全性;最后,对所设计的安全冗余机制进行台架试验。结果表明,在单侧桥驱芯片故障、单侧电机位置传感器故障、双侧电机位置传感器故障等故障注入的情况下,系统能够实现预期响应,满足功能安全目标,验证了所设计安全冗余机制的有效性。展开更多
本文指出现代高层建筑、超高层建筑兴起发展背景下,建筑内部普遍覆盖有多类电气产品,不同产品应用方向和参数存在差异,应急照明电源(Emergency Power Supply,EPS)能够有效提升建筑供配电设计中照明系统的智能性、稳定性。本文分析了建...本文指出现代高层建筑、超高层建筑兴起发展背景下,建筑内部普遍覆盖有多类电气产品,不同产品应用方向和参数存在差异,应急照明电源(Emergency Power Supply,EPS)能够有效提升建筑供配电设计中照明系统的智能性、稳定性。本文分析了建筑工程供配电设计中应急照明电源EPS的运用现状、优势特征,系统性总结阐述了建筑工程供配电系统设计中应急照明电源EPS的运用方法、容量计算方法,通过实际案例为EPS配置计算作了引用论述,并就EPS常见维护问题进行了综合论述,旨在进一步完善建筑工程供配电设计中EPS运用研究理论依据,为相关工作提供参考。展开更多
It has been revealed that prolonged shelter life caused by Fukushima Daiichi Nuclear Power Station accident in conjunction with the Great East Japan Earthquake influences sleep and mental health of the residents, and ...It has been revealed that prolonged shelter life caused by Fukushima Daiichi Nuclear Power Station accident in conjunction with the Great East Japan Earthquake influences sleep and mental health of the residents, and therefore its influence on their physical and emotional health has become a concern. Therefore, in this study, the authors aimed at clarifying actual situations of sleep and stress of middle age males living in shelters for a long period in each of emergency temporary houses and post-earthquake public houses. For 5 males who moved from emergency temporary houses to post-earthquake public houses, their objective and subjective sleep states were measured with Actigraph and PSQI, respectively. Furthermore, their objective and subjective stresses were measured with saliva stress biomarkers and GHQ28, respectively. Their data were analyzed by paired t-test. As result, in comparison between the life in the emergency temporary houses and post-earthquake public houses, significant variation was not recognized in their objective sleep states and saliva stress biomarkers though their subjective sleep and subjective stress were significantly worsened after moving to the post-earthquake public houses.展开更多
Emergency control is an essential means to help system maintain synchronism after fault clearance.Traditional“offline calculation,online matching”scheme faces significant challenges on adaptiveness and robustness pr...Emergency control is an essential means to help system maintain synchronism after fault clearance.Traditional“offline calculation,online matching”scheme faces significant challenges on adaptiveness and robustness problems.To address these challenges,this paper proposes a novel closed-loop framework of transient stability prediction(TSP)and emergency control based on Deep Belief Network(DBN).First,a hierarchical real-time anti-jitter TSP method using sliding time windows is adopted,which takes into account accuracy and rapidity at the same time.Next,a sensitivity regression model is established to mine the implicit relationship between power angles and sensitivity.When impending instability of the system is foreseen,optimal emergency control strategy can be determined in time.Lastly,responses after emergency control are fed back to the TSP model.If prediction result is still unstable,an additional control strategy will be implemented.Comprehensive numerical case studies are conducted on New England IEEE 39-bus system and Northeast Power Coordinated Council(NPCC)140-bus system.Results show the proposed method can detect instability of system as soon as possible and assist in maintaining reliable system synchronism.展开更多
The purpose of this study is to establish an intelligent expert system for nuclear power plant emergency response.A new framework of environmental risk management methodology by the concept of pattern recognition was ...The purpose of this study is to establish an intelligent expert system for nuclear power plant emergency response.A new framework of environmental risk management methodology by the concept of pattern recognition was introduced in this paper.A knowledge-based decision support system for emergency response and risk management of nuclear power plant was also discussed.The mathematical pattern relationship of accidental release effects on neighboring area and the corresponding response measures were presented in this paper.With this decision system,the decision maker can specify the procedure and minimize their human error in the decision process.The improvement of risk response and the quality of management system could be upgraded by this system.Besides,the methodology can also be served as a basis for the future development of environmental risk response system design.展开更多
Inter-regional transmission line fault often results in power flow transferring, tie-line overloading and system islanding. Traditional control methods such asgenerator tripping and load shedding are costly, and also ...Inter-regional transmission line fault often results in power flow transferring, tie-line overloading and system islanding. Traditional control methods such asgenerator tripping and load shedding are costly, and also have undesirable impacts on theloadside. In this paper, a new emergency power control strategy is proposed for multi-channel interconnected system by using the overload capacity of non-fault DC lines. First of all, the capacity of emergency power control can be acquired by critical transmission power of a certain tie-line for stability. Secondly, the shortest electric distance can be calculated by Dijkstra algorithm, and then the priority of emergency control of the DC lines can be obtained by the entropy weight method. When the inter-regional transmission power decreases and the effect of single DC line emergency control is poor, the multi-channel cooperative emergency control strategy is proposed to ensure the system stability. Simulation results verify the effectiveness of the method proposed.展开更多
HVDC auxiliary power control can significantly improve the transient stability of AC/DC power grid.An HVDC adaptive emergency power support method based on unbalanced power on line estimation is proposed in this paper...HVDC auxiliary power control can significantly improve the transient stability of AC/DC power grid.An HVDC adaptive emergency power support method based on unbalanced power on line estimation is proposed in this paper.By establishing the extended state equation of the system,the on line dynamic estimation of unbalanced power of the system was realized.On this basis,power support was realized based on the principle of the ladder increment.The optimal DC was selected by the power support factor,and the emergency power support controller was installed on the DC.This emergency power support method can realize dynamic optimal power support with minimized control cost.The three infeed HVDC system was built on PSCAD.The simulation results show the effectiveness of the proposed method.展开更多
Police emergency commitment powers for detention of persons in the community perceived to be seriously mentally ill for further specialist examination in a designated facility have always raised interest in medical an...Police emergency commitment powers for detention of persons in the community perceived to be seriously mentally ill for further specialist examination in a designated facility have always raised interest in medical and legal circles on both sides of the Atlantic. The objective of this article is to detail the police commitment procedure in England and Wales, as dictated by the mental health act of 1983 (MHA 1983) amended in 2007 (MHA 2007);and compare this with similar legal provisions as prevails under current state mental health statutes in the United States of America (USA). The comparative review of the commitment processes in England and Wales to that of the USA reveals that the process in England and Wales seeks to primarily ensure that persons with mental disorder (PWMD) in crisis are directed to a specialist hospital for evaluation and appropriate specialist care. In the USA such persons in a good number of cases may end up in the criminal justice system due to application of the “dangerousness” standard. Additionally whereas in England and Wales the commitment law is uniform in law and application, the federal system in the USA is such that the commitment law may have minor variations depending on the individual states. The minor variation in state commitment laws may engender a situation where the commitment law in England and Wales may seem relatively equitable and just towards PWMD in crisis, compared to the state commitment laws in the USA.展开更多
APF-EPS系统在APF(Active Power Filter)有源滤波器的主框架上构建EPS(Emergency Power Supply),实现应急供电系统的自动化管理。系统在保证供电电能质量的同时,按需要提供紧急备用供电电源。APF-EPS系统,合理考虑了APF和EPS在使用时间...APF-EPS系统在APF(Active Power Filter)有源滤波器的主框架上构建EPS(Emergency Power Supply),实现应急供电系统的自动化管理。系统在保证供电电能质量的同时,按需要提供紧急备用供电电源。APF-EPS系统,合理考虑了APF和EPS在使用时间上和性能结构上的互补性,不仅节约硬件成本,更能合理有效地协调APF和EPS,增强了系统的实用性。给出了APF-EPS系统的构建框架,并进行了仿真分析。展开更多
文摘Single-phase 25 kV traction networks of electrified alternating current(AC)railways create electromagnetic fields(EMFs)with significant levels of intensity.The most intense magnetic fields occur when short circuits exist between the contact wire and rails or ground.Despite the short duration of exposure,they can adversely affect electronic devices and induce significant voltages in adjacent power lines,which is dangerous for operating personnel.Although numerous investigations have focused on modeling the EMF of traction networks and power lines,the challenge of determining the three-dimensional electromagnetic fields near metal supports during the flow of a short-circuit current through them is yet to be resolved.In this case,the field has a complex spatial structure that significantly complicates the calculations of intensities.This study proposes a methodology,algorithms,software,and digital models for determining the EMF in the described emergency scenarios.During the modeling process,the objects being studied were represented by segments of thin wires to analyze the distribution of the electric charge and calculate the intensities of the electric and magnetic fields.This approach was implemented in the Fazonord software,and the modeling results show a substantial increase in EMF levels close to the support,with a noticeable decrease in the levels as the distance from it increases.The procedure implemented in the commercial software Fazonord is universal and can be used to determine electromagnetic fields at any electrical power facility that includes live parts of limited length.Based on the proposed procedure,the EMF near the supports of overhead power lines and traction networks of various designs could be determined,the EMF levels at substations can be calculated,and the influence of metal structures located near traction networks,such as pedestrian crossings at railway stations,can be considered.
文摘电动助力转向(electric power steering,EPS)系统是车辆常用的转向执行器,其失效将严重影响驾乘人员的安全。为提高EPS系统的安全性与可靠性,基于功能安全标准建立EPS系统安全冗余机制:基于ISO26262对EPS系统进行研究,通过相关项定义、危害分析与风险评估(HARA),得到系统的功能安全目标与需求,并对其进行分配;设计EPS系统架构、容错机制,以提高系统的安全性;最后,对所设计的安全冗余机制进行台架试验。结果表明,在单侧桥驱芯片故障、单侧电机位置传感器故障、双侧电机位置传感器故障等故障注入的情况下,系统能够实现预期响应,满足功能安全目标,验证了所设计安全冗余机制的有效性。
文摘本文指出现代高层建筑、超高层建筑兴起发展背景下,建筑内部普遍覆盖有多类电气产品,不同产品应用方向和参数存在差异,应急照明电源(Emergency Power Supply,EPS)能够有效提升建筑供配电设计中照明系统的智能性、稳定性。本文分析了建筑工程供配电设计中应急照明电源EPS的运用现状、优势特征,系统性总结阐述了建筑工程供配电系统设计中应急照明电源EPS的运用方法、容量计算方法,通过实际案例为EPS配置计算作了引用论述,并就EPS常见维护问题进行了综合论述,旨在进一步完善建筑工程供配电设计中EPS运用研究理论依据,为相关工作提供参考。
文摘It has been revealed that prolonged shelter life caused by Fukushima Daiichi Nuclear Power Station accident in conjunction with the Great East Japan Earthquake influences sleep and mental health of the residents, and therefore its influence on their physical and emotional health has become a concern. Therefore, in this study, the authors aimed at clarifying actual situations of sleep and stress of middle age males living in shelters for a long period in each of emergency temporary houses and post-earthquake public houses. For 5 males who moved from emergency temporary houses to post-earthquake public houses, their objective and subjective sleep states were measured with Actigraph and PSQI, respectively. Furthermore, their objective and subjective stresses were measured with saliva stress biomarkers and GHQ28, respectively. Their data were analyzed by paired t-test. As result, in comparison between the life in the emergency temporary houses and post-earthquake public houses, significant variation was not recognized in their objective sleep states and saliva stress biomarkers though their subjective sleep and subjective stress were significantly worsened after moving to the post-earthquake public houses.
基金supported in part by the Fundamental Research Funds for the Central Universities(No.2020YJS162)the National Key R&D Program of China(No.2018YFB0904500)Science and Technology Projects of State Grid Corporation of China(No.SGLNDK00KJJS1800236).
文摘Emergency control is an essential means to help system maintain synchronism after fault clearance.Traditional“offline calculation,online matching”scheme faces significant challenges on adaptiveness and robustness problems.To address these challenges,this paper proposes a novel closed-loop framework of transient stability prediction(TSP)and emergency control based on Deep Belief Network(DBN).First,a hierarchical real-time anti-jitter TSP method using sliding time windows is adopted,which takes into account accuracy and rapidity at the same time.Next,a sensitivity regression model is established to mine the implicit relationship between power angles and sensitivity.When impending instability of the system is foreseen,optimal emergency control strategy can be determined in time.Lastly,responses after emergency control are fed back to the TSP model.If prediction result is still unstable,an additional control strategy will be implemented.Comprehensive numerical case studies are conducted on New England IEEE 39-bus system and Northeast Power Coordinated Council(NPCC)140-bus system.Results show the proposed method can detect instability of system as soon as possible and assist in maintaining reliable system synchronism.
基金Supported by Jinwen University of Science and Technology
文摘The purpose of this study is to establish an intelligent expert system for nuclear power plant emergency response.A new framework of environmental risk management methodology by the concept of pattern recognition was introduced in this paper.A knowledge-based decision support system for emergency response and risk management of nuclear power plant was also discussed.The mathematical pattern relationship of accidental release effects on neighboring area and the corresponding response measures were presented in this paper.With this decision system,the decision maker can specify the procedure and minimize their human error in the decision process.The improvement of risk response and the quality of management system could be upgraded by this system.Besides,the methodology can also be served as a basis for the future development of environmental risk response system design.
文摘Inter-regional transmission line fault often results in power flow transferring, tie-line overloading and system islanding. Traditional control methods such asgenerator tripping and load shedding are costly, and also have undesirable impacts on theloadside. In this paper, a new emergency power control strategy is proposed for multi-channel interconnected system by using the overload capacity of non-fault DC lines. First of all, the capacity of emergency power control can be acquired by critical transmission power of a certain tie-line for stability. Secondly, the shortest electric distance can be calculated by Dijkstra algorithm, and then the priority of emergency control of the DC lines can be obtained by the entropy weight method. When the inter-regional transmission power decreases and the effect of single DC line emergency control is poor, the multi-channel cooperative emergency control strategy is proposed to ensure the system stability. Simulation results verify the effectiveness of the method proposed.
基金the National Natural Science Foundation of China(Grant No.51607158)the Key Scientific Technological Project in Henan Province(Grant No.192102210075)。
文摘HVDC auxiliary power control can significantly improve the transient stability of AC/DC power grid.An HVDC adaptive emergency power support method based on unbalanced power on line estimation is proposed in this paper.By establishing the extended state equation of the system,the on line dynamic estimation of unbalanced power of the system was realized.On this basis,power support was realized based on the principle of the ladder increment.The optimal DC was selected by the power support factor,and the emergency power support controller was installed on the DC.This emergency power support method can realize dynamic optimal power support with minimized control cost.The three infeed HVDC system was built on PSCAD.The simulation results show the effectiveness of the proposed method.
文摘Police emergency commitment powers for detention of persons in the community perceived to be seriously mentally ill for further specialist examination in a designated facility have always raised interest in medical and legal circles on both sides of the Atlantic. The objective of this article is to detail the police commitment procedure in England and Wales, as dictated by the mental health act of 1983 (MHA 1983) amended in 2007 (MHA 2007);and compare this with similar legal provisions as prevails under current state mental health statutes in the United States of America (USA). The comparative review of the commitment processes in England and Wales to that of the USA reveals that the process in England and Wales seeks to primarily ensure that persons with mental disorder (PWMD) in crisis are directed to a specialist hospital for evaluation and appropriate specialist care. In the USA such persons in a good number of cases may end up in the criminal justice system due to application of the “dangerousness” standard. Additionally whereas in England and Wales the commitment law is uniform in law and application, the federal system in the USA is such that the commitment law may have minor variations depending on the individual states. The minor variation in state commitment laws may engender a situation where the commitment law in England and Wales may seem relatively equitable and just towards PWMD in crisis, compared to the state commitment laws in the USA.
文摘APF-EPS系统在APF(Active Power Filter)有源滤波器的主框架上构建EPS(Emergency Power Supply),实现应急供电系统的自动化管理。系统在保证供电电能质量的同时,按需要提供紧急备用供电电源。APF-EPS系统,合理考虑了APF和EPS在使用时间上和性能结构上的互补性,不仅节约硬件成本,更能合理有效地协调APF和EPS,增强了系统的实用性。给出了APF-EPS系统的构建框架,并进行了仿真分析。
