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
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
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
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.
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.