Distributed generators now is widely used in electrical power networks, in some cases it works seasonally, and some types works at special weather conditions like photo voltaic systems and wind energy, and due to this...Distributed generators now is widely used in electrical power networks, in some cases it works seasonally, and some types works at special weather conditions like photo voltaic systems and wind energy, and due to this continuous changes in generation condition, the fault current level in network will be affected, this changes in fault current level will affect in the coordination between protection relays and to keep the coordination at right way, an adaptive protection system is required that can adaptive its setting according to generation changes, the fault current level in each case is evaluated using ETAP software, and the required relay setting in each case is also evaluated using Grey Wolf Optimizer (GWO) algorithm, and to select suitable setting which required in each condition, to select the active setting group of protection relay according to generation capacity, central protection unite can be used, and to improve protection stability and minimizing relays tripping time, a proposed method for selecting suitable backup relay is used, which leads to decrease relays tripping time and increase system stability, output settings for relays in all cases achieved our constrains.展开更多
During its rise as a world power, the United States(U.S.) adopted a traditional form of mercantilism, and most US politicians followed a protectionist approach. From the end of the Civil War to the eve of World War I,...During its rise as a world power, the United States(U.S.) adopted a traditional form of mercantilism, and most US politicians followed a protectionist approach. From the end of the Civil War to the eve of World War I, the United States blazed a new trail of industrial development and implemented protective policies such as high tariffs. This historical tradition has had a profound influence on some current US politicians. After the collapse of the Bretton Woods system, the United States developed a new form of mercantilism, as manifested in the emergence of nontariff barriers instead of tariff barriers to restrict imports and protect domestic industries and employment. Although export regulations have avoided affecting the technology industry, they have led to hefty trade deficits for the United States. National interests have prevailed in U.S. decision-making and have influenced its choices to accede to or walk away from international organizations or treaties. The dollar's hegemony has played a pivotal role in U.S. economic policymaking. These factors have led to the twin deficits in the U.S. economy, i.e. a trade deficit and a fiscal deficit. The real intention of the United States in waging a trade war against China is to maintain and even strengthen the dollar's hegemony and the U.S.' international predominance.展开更多
I. Introduction This paper discusses child protection in the United States. I will discuss four general topics. The first topic is United States laws on the protection of children from child abuse and neglect. The se...I. Introduction This paper discusses child protection in the United States. I will discuss four general topics. The first topic is United States laws on the protection of children from child abuse and neglect. The second topic is providing care for children who must be removed from their homes. The third is the role of courts in child protection in the United States.展开更多
Although the new technology of protection and automation system of substation based on IEC61850 standard has developed rapidly in China,reliability measures depending on this technology need to be further researched.B...Although the new technology of protection and automation system of substation based on IEC61850 standard has developed rapidly in China,reliability measures depending on this technology need to be further researched.By taking advantage of convenient information sharing,two kinds of new schemes,shared backup protection unit(SBPU)and signal backup(SB),have been proposed to solve the failure problem of protective devices and current/voltage transducers respectively,and the working principle of these two schemes are also described.Furthermore,the key technologies of on-line diagnosis of protective devices'failure and on-line status diagnosis of optical or electronic current/voltage transducers to realize the two schemes are proposed.展开更多
In order to rapidly clear a fault in all-parallel autotransformer(AT)railway system,the existing protection scheme trips both faulted line and healthy line.To solve this problem,a novel unit protection scheme is propo...In order to rapidly clear a fault in all-parallel autotransformer(AT)railway system,the existing protection scheme trips both faulted line and healthy line.To solve this problem,a novel unit protection scheme is proposed in this paper.From fault characteristics measured at substation(SS),AT station(ATS)and section post(SP),we can observe that SS protective relays can detect all the faults but could not be selective,and ATS or SP relays can discriminate the faulted line but not sensitively enough;therefore,we make full use of the fault characteristics and propose a novel unit protection scheme.We employ directional distance protections at SS,ATS and SP,and unify them with networked inter-tripping signals and interlocking signals.When a forward distance protection detects a fault and does not receive inter-locking signals from reverse distance protections of other relays in a short setting time,it will trip the relevant circuit breaker and send an inter-tripping signal to other relays in the same protection unit.Field test results show the proposed scheme trips only the faulted line rapidly and never interrupts the power supply of healthy lines;therefore,the proposed protection scheme obtains both selectivity and speed.展开更多
目前,我国正处于国家公园体制稳步推进,自然保护地体系转型重构的关键时期,明确国家公园的发展思路与理念是我们亟待解决的关键问题。National Parks:The American Experience一书较为全面地探讨了美国国家公园体系的发展历程及发展理...目前,我国正处于国家公园体制稳步推进,自然保护地体系转型重构的关键时期,明确国家公园的发展思路与理念是我们亟待解决的关键问题。National Parks:The American Experience一书较为全面地探讨了美国国家公园体系的发展历程及发展理念变迁,讲述了联邦政府、铁路公司和环保组织等利益团体围绕"国家公园该如何发展"这条主线展开的一系列博弈过程,涵盖了重要的历史事件、关键的推动性人物及相关开创性法案等内容。书中对推动美国国家公园发展的思潮和理念做了总结回顾,尤其是国家公园应该"保护什么"以及"如何保护"的思考,对完善我国国家公园体制、重构自然保护地体系具有一定的借鉴和启示意义。展开更多
Research on the evolution of cultural policy is the key in the field of public policy study,and it is also an important means to solve the problems that have emerged in cultural heritage management.The National Cultur...Research on the evolution of cultural policy is the key in the field of public policy study,and it is also an important means to solve the problems that have emerged in cultural heritage management.The National Cultural Park is an innovative cultural heritage protection system proposed by Chinese leaders within the context of national rejuvenation and building a culturally-strong country campaign.From the perspective of system evolution theory,this paper systematically sorts out the ideas behind international heritage management and the evolutionary process of the Cultural Relics Protection Unit system,in an effort to explore the origin,innovation and vision of the National Cultural Park System.A review of the international heritage documents revealed that the principle of heritage protection has developed from“authenticity”to“integrity”,and the focus of the protection object has also changed from“monism”to“diversity”,which provided a theoretical background for the burgeoning National Cultural Park.The Cultural Relics Protection Unit system has been promoted as the most crucial cultural heritage management system in China.Therefore,this study sheds light on the evolution and limitations of the system that lays a practical foundation for the National Cultural Park System.There have been three stages in the history of China’s National Cultural Relics Protection Unit,namely,the creation of the system(1956–1965),the survival crisis of the system(1966–1977),and the rebirth and development of the system(1978 to the present),in which the main driving concepts of China's cultural heritage management have been sequentially elucidated as simple protectionism,tolerant conservatism and comprehensive developmentalism,respectively.Since the establishment of China’s Cultural Relics Protection Unit system,tremendous progress has been made not only in the enlightenment of the public’s mindset and but also in the development of system and culture.However,the changes in the institutional environment gradually exposed its limitations regarding cultural relic management and value expression.The National Cultural Park System is the fruit created by the internal contradictions of the cultural heritage system itself and the evolution of heritage theory.Its biggest innovation lies in the two core connotations of“integrated protection”and“integrated development”.In the future,as the National Cultural Park management system matures,a Chinese cultural heritage management system will take shape in which the National Cultural Parks become dominant and various cultural resources are utilized.Finally,the National Cultural Park will become a symbol of Chinese culture and will be internalized into the common belief system of the Chinese nation.展开更多
文摘Distributed generators now is widely used in electrical power networks, in some cases it works seasonally, and some types works at special weather conditions like photo voltaic systems and wind energy, and due to this continuous changes in generation condition, the fault current level in network will be affected, this changes in fault current level will affect in the coordination between protection relays and to keep the coordination at right way, an adaptive protection system is required that can adaptive its setting according to generation changes, the fault current level in each case is evaluated using ETAP software, and the required relay setting in each case is also evaluated using Grey Wolf Optimizer (GWO) algorithm, and to select suitable setting which required in each condition, to select the active setting group of protection relay according to generation capacity, central protection unite can be used, and to improve protection stability and minimizing relays tripping time, a proposed method for selecting suitable backup relay is used, which leads to decrease relays tripping time and increase system stability, output settings for relays in all cases achieved our constrains.
基金funded by the National Social Sciences Fund (NSSF) project “Study on U.S. Mercantilist Tradition and New Forms of Mercantilism (Approval No. 17BJL021)”
文摘During its rise as a world power, the United States(U.S.) adopted a traditional form of mercantilism, and most US politicians followed a protectionist approach. From the end of the Civil War to the eve of World War I, the United States blazed a new trail of industrial development and implemented protective policies such as high tariffs. This historical tradition has had a profound influence on some current US politicians. After the collapse of the Bretton Woods system, the United States developed a new form of mercantilism, as manifested in the emergence of nontariff barriers instead of tariff barriers to restrict imports and protect domestic industries and employment. Although export regulations have avoided affecting the technology industry, they have led to hefty trade deficits for the United States. National interests have prevailed in U.S. decision-making and have influenced its choices to accede to or walk away from international organizations or treaties. The dollar's hegemony has played a pivotal role in U.S. economic policymaking. These factors have led to the twin deficits in the U.S. economy, i.e. a trade deficit and a fiscal deficit. The real intention of the United States in waging a trade war against China is to maintain and even strengthen the dollar's hegemony and the U.S.' international predominance.
文摘I. Introduction This paper discusses child protection in the United States. I will discuss four general topics. The first topic is United States laws on the protection of children from child abuse and neglect. The second topic is providing care for children who must be removed from their homes. The third is the role of courts in child protection in the United States.
基金National Natural Science Foundation of China(No.50777068).
文摘Although the new technology of protection and automation system of substation based on IEC61850 standard has developed rapidly in China,reliability measures depending on this technology need to be further researched.By taking advantage of convenient information sharing,two kinds of new schemes,shared backup protection unit(SBPU)and signal backup(SB),have been proposed to solve the failure problem of protective devices and current/voltage transducers respectively,and the working principle of these two schemes are also described.Furthermore,the key technologies of on-line diagnosis of protective devices'failure and on-line status diagnosis of optical or electronic current/voltage transducers to realize the two schemes are proposed.
基金supported in part by the National Natural Science Foundation of China under Grant No.52177116,51777174in part by the Sichuan Science and Technology Program under Grant No.2023JDRC0002.
文摘In order to rapidly clear a fault in all-parallel autotransformer(AT)railway system,the existing protection scheme trips both faulted line and healthy line.To solve this problem,a novel unit protection scheme is proposed in this paper.From fault characteristics measured at substation(SS),AT station(ATS)and section post(SP),we can observe that SS protective relays can detect all the faults but could not be selective,and ATS or SP relays can discriminate the faulted line but not sensitively enough;therefore,we make full use of the fault characteristics and propose a novel unit protection scheme.We employ directional distance protections at SS,ATS and SP,and unify them with networked inter-tripping signals and interlocking signals.When a forward distance protection detects a fault and does not receive inter-locking signals from reverse distance protections of other relays in a short setting time,it will trip the relevant circuit breaker and send an inter-tripping signal to other relays in the same protection unit.Field test results show the proposed scheme trips only the faulted line rapidly and never interrupts the power supply of healthy lines;therefore,the proposed protection scheme obtains both selectivity and speed.
文摘目前,我国正处于国家公园体制稳步推进,自然保护地体系转型重构的关键时期,明确国家公园的发展思路与理念是我们亟待解决的关键问题。National Parks:The American Experience一书较为全面地探讨了美国国家公园体系的发展历程及发展理念变迁,讲述了联邦政府、铁路公司和环保组织等利益团体围绕"国家公园该如何发展"这条主线展开的一系列博弈过程,涵盖了重要的历史事件、关键的推动性人物及相关开创性法案等内容。书中对推动美国国家公园发展的思潮和理念做了总结回顾,尤其是国家公园应该"保护什么"以及"如何保护"的思考,对完善我国国家公园体制、重构自然保护地体系具有一定的借鉴和启示意义。
基金The China National Social Science Fund of Art Sciences(20ZD02).
文摘Research on the evolution of cultural policy is the key in the field of public policy study,and it is also an important means to solve the problems that have emerged in cultural heritage management.The National Cultural Park is an innovative cultural heritage protection system proposed by Chinese leaders within the context of national rejuvenation and building a culturally-strong country campaign.From the perspective of system evolution theory,this paper systematically sorts out the ideas behind international heritage management and the evolutionary process of the Cultural Relics Protection Unit system,in an effort to explore the origin,innovation and vision of the National Cultural Park System.A review of the international heritage documents revealed that the principle of heritage protection has developed from“authenticity”to“integrity”,and the focus of the protection object has also changed from“monism”to“diversity”,which provided a theoretical background for the burgeoning National Cultural Park.The Cultural Relics Protection Unit system has been promoted as the most crucial cultural heritage management system in China.Therefore,this study sheds light on the evolution and limitations of the system that lays a practical foundation for the National Cultural Park System.There have been three stages in the history of China’s National Cultural Relics Protection Unit,namely,the creation of the system(1956–1965),the survival crisis of the system(1966–1977),and the rebirth and development of the system(1978 to the present),in which the main driving concepts of China's cultural heritage management have been sequentially elucidated as simple protectionism,tolerant conservatism and comprehensive developmentalism,respectively.Since the establishment of China’s Cultural Relics Protection Unit system,tremendous progress has been made not only in the enlightenment of the public’s mindset and but also in the development of system and culture.However,the changes in the institutional environment gradually exposed its limitations regarding cultural relic management and value expression.The National Cultural Park System is the fruit created by the internal contradictions of the cultural heritage system itself and the evolution of heritage theory.Its biggest innovation lies in the two core connotations of“integrated protection”and“integrated development”.In the future,as the National Cultural Park management system matures,a Chinese cultural heritage management system will take shape in which the National Cultural Parks become dominant and various cultural resources are utilized.Finally,the National Cultural Park will become a symbol of Chinese culture and will be internalized into the common belief system of the Chinese nation.
