Microseismic/acoustic emission(MS/AE)source localization method is crucial for predicting and controlling of potentially dangerous sources of complex structures.However,the locating errors induced by both the irregula...Microseismic/acoustic emission(MS/AE)source localization method is crucial for predicting and controlling of potentially dangerous sources of complex structures.However,the locating errors induced by both the irregular structure and pre-measured velocity are poorly understood in existing methods.To meet the high-accuracy locating requirements in complex three-dimensional hole-containing structures,a velocity-free MS/AE source location method is developed in this paper.It avoids manual repetitive training by using equidistant grid points to search the path,which introduces A*search algorithm and uses grid points to accommodate complex structures with irregular holes.It also takes advantage of the velocity-free source location method.To verify the validity of the proposed method,lead-breaking tests were performed on a cubic concrete test specimen with a size of 10 cm10 cm10 cm.It was cut out into a cylindrical empty space with a size of/6cm10 cm.Based on the arrivals,the classical Geiger method and the proposed method are used to locate lead-breaking sources.Results show that the locating error of the proposed method is 1.20 cm,which is less than 2.02 cm of the Geiger method.Hence,the proposed method can effectively locate sources in the complex three-dimensional structure with holes and achieve higher precision requirements.展开更多
According to earthquake catalog records of Fujian Seismic Network, the Tnow method and the fourstation continuous location method put forward by Jin Xing are inspected by using P-wave arrival information of the first ...According to earthquake catalog records of Fujian Seismic Network, the Tnow method and the fourstation continuous location method put forward by Jin Xing are inspected by using P-wave arrival information of the first four stations in each earthquake. It shows that the fourstation continuous location method can locate more seismic events than the Tnow method. By analyzing the results, it is concluded that the reason for this is that the Tnow method makes use of information from stations without being triggered, while some stations failed to be reflected in earthquake catalog because of discontinuous records or unclear records of seismic phases. For seismic events whose location results can be given, there is no obvious difference in location results of the two methods and positioning deviation of most seismic events is also not significant. For earthquakes outside the network, the positioning deviation may amplify as the epicentral distance enlarges, which may relate to the situation that the seismic stations are centered on one side of epicenter and the opening angle between seismic stations used for location and epicenter is small.展开更多
As one of the new generation flexible AC transmission systems(FACTS)devices,the interline power flow controller(IPFC)has the significant advantage of simultaneously regulating the power flow of multiple lines.Neverthe...As one of the new generation flexible AC transmission systems(FACTS)devices,the interline power flow controller(IPFC)has the significant advantage of simultaneously regulating the power flow of multiple lines.Nevertheless,how to choose the appropriate location for the IPFC converters has not been discussed thoroughly.To solve this problem,this paper proposes a novel location method for IPFC using entropy theory.To clarify IPFC’s impact on system power flow,its operation mechanism and control strategies of different types of serial converters are discussed.Subsequently,to clarify the system power flow characteristic suitable for device location analysis,the entropy concept is introduced.In this process,the power flow distribution entropy index is used as an optimization index.Using this index as a foundation,the power flow transfer entropy index is also generated and proposed for the IPFC location determination study.Finally,electromechanical electromagnetic hybrid simulations based on ADPSS are implemented for validation.These are tested in a practical power grid with over 800 nodes.A modular multilevel converter(MMC)-based IPFC electromagnetic model is also established for precise verification.The results show that the proposed method can quickly and efficiently complete optimized IPFC location and support IPFC to determine an optimal adjustment in the N-1 fault cases.展开更多
For facing the challenges brought by large-scale renewable energy having access to the system and considering the key technologies of energy Internet,it is very necessary to put forward the location method of distribu...For facing the challenges brought by large-scale renewable energy having access to the system and considering the key technologies of energy Internet,it is very necessary to put forward the location method of distribution network equipment and capacity from the perspective of life cycle cost.Compared with the traditional energy network,the equipment capacity problem of energy interconnected distribution network which involves in electricity network,thermal energy network and natural gas network is comprehensively considered in this paper.On this basis,firstly,the operation architecture of energy interconnected distribution network is designed.Secondly,taking the grid connection location and configuration capacity of key equipment in the system as the control variables and the operation cost of system comprehensive planning in the whole life cycle as the goal,the equipment location and capacity optimization model of energy interconnected distribution network is established.Finally,an IEEE 33 bus energy mutual distribution grid system is taken for example analysis,and the improved chaotic particle swarmoptimization algorithm is used to solve it.The simulation results show that the method proposed in this paper is suitable for the equipment location and capacity planning of energy interconnected distribution network,and it can effectively improve the social and economic benefits of system operation.展开更多
We have selected 171 near-field records from 391 aftershock records of the Lulong, Hebei Province, earthquake in October 1982 and relocated the hypocenter of 45 aftershocks using the program Hypoinverse. The distribut...We have selected 171 near-field records from 391 aftershock records of the Lulong, Hebei Province, earthquake in October 1982 and relocated the hypocenter of 45 aftershocks using the program Hypoinverse. The distribution of aftershocks reveals a set of earthquake faults: a WNW stretching fault truncates two NNE stretching faults. The two branches of faults show the conjugate structure which is often seen in brittle fracture. The NNE stretching faults are connected together. The Luanhe river valley near Lulong developed to a rudiment rift basin surrounded by a series of faults. The fault of Lulong earthquake is a strike-slip fault with tension component. This fault type matches with the activity of Zhangjiakou-Bohai seismic belt (Zhang-Bo belt) and also shows the action of Zhang-Bo belt as a boundary of two secondary active blocks that truncates the NNE fault.展开更多
In recent years,Structural Health Monitoring (SHM) has emerged as a new research area in civil engineering.Most existing health monitoring methodologies require direct measurement of input excitation for implementatio...In recent years,Structural Health Monitoring (SHM) has emerged as a new research area in civil engineering.Most existing health monitoring methodologies require direct measurement of input excitation for implementation.However,in many cases,there is no easy way to measure these inputs-or alternatively to externally excite the structure.Therefore,SHM methods based on ambient vibration have become important in civil engineering.In this paper,an approach is proposed based on the Damage Location Vector (DLV) method to handle the ambient vibration case.Here,this flexibility-matrix-based damage localization method is combined with a modal expansion technique to eliminate the need to measure the input excitation.As a by-product of this approach,in addition to determining the location of the damage,an estimate of the damage extent also can be determined.Finally,a numerical example analyzing a truss structure with limited sensors and noisy measurement is provided to verify the efficacy of the proposed approach.展开更多
An iteration method for correcting the target coordinates determined by a locating system with a Cartesian array is reported. Under the complex hydrological condition, the method can give the target position not only ...An iteration method for correcting the target coordinates determined by a locating system with a Cartesian array is reported. Under the complex hydrological condition, the method can give the target position not only accurately but also quickly. The preliminary experimental results show that the correction is effective. An application of the method has been completed.展开更多
This paper presents results of model tests for the landslide dam failure of a single dam and cascade dams in a sloping channel. The dams were designed to be regular trapezoid with fine sand. A new measuring method nam...This paper presents results of model tests for the landslide dam failure of a single dam and cascade dams in a sloping channel. The dams were designed to be regular trapezoid with fine sand. A new measuring method named the labeled line locating method was used to digitalize the captured instantaneous pictures. Under two different inflow discharges, the morphological evolution and the flow patterns during one dam failure and the failure of cascade dams were investigated. The results indicate that when the inflow discharge is large, the deformation pattern of the downstream dam is similar to that of the upstream dam, and both dams are characterized with the overtopping scour throughout the dam failure process. When the inflow discharge is small, the upstream dam is scoured mainly through a sluice slot formed by the longitudinal incision, and the downstream dam is characterized with the overtopping scour. The data set presented in this paper can be used for the validation of numerical models and provide a reference for the flood risk management of cascade landslide dams.展开更多
基金The authors wish to acknowledge financial support from the National Natural Science Foundation of China(51822407 and 51774327)Natural Science Foundation of Hunan Province in China(2018JJ1037)Innovation Driven project of Central South University(2020CX014).
文摘Microseismic/acoustic emission(MS/AE)source localization method is crucial for predicting and controlling of potentially dangerous sources of complex structures.However,the locating errors induced by both the irregular structure and pre-measured velocity are poorly understood in existing methods.To meet the high-accuracy locating requirements in complex three-dimensional hole-containing structures,a velocity-free MS/AE source location method is developed in this paper.It avoids manual repetitive training by using equidistant grid points to search the path,which introduces A*search algorithm and uses grid points to accommodate complex structures with irregular holes.It also takes advantage of the velocity-free source location method.To verify the validity of the proposed method,lead-breaking tests were performed on a cubic concrete test specimen with a size of 10 cm10 cm10 cm.It was cut out into a cylindrical empty space with a size of/6cm10 cm.Based on the arrivals,the classical Geiger method and the proposed method are used to locate lead-breaking sources.Results show that the locating error of the proposed method is 1.20 cm,which is less than 2.02 cm of the Geiger method.Hence,the proposed method can effectively locate sources in the complex three-dimensional structure with holes and achieve higher precision requirements.
文摘According to earthquake catalog records of Fujian Seismic Network, the Tnow method and the fourstation continuous location method put forward by Jin Xing are inspected by using P-wave arrival information of the first four stations in each earthquake. It shows that the fourstation continuous location method can locate more seismic events than the Tnow method. By analyzing the results, it is concluded that the reason for this is that the Tnow method makes use of information from stations without being triggered, while some stations failed to be reflected in earthquake catalog because of discontinuous records or unclear records of seismic phases. For seismic events whose location results can be given, there is no obvious difference in location results of the two methods and positioning deviation of most seismic events is also not significant. For earthquakes outside the network, the positioning deviation may amplify as the epicentral distance enlarges, which may relate to the situation that the seismic stations are centered on one side of epicenter and the opening angle between seismic stations used for location and epicenter is small.
基金supported by the Natural Science Foundation of Sichuan Province of China(No.2022NSFSC0262)the Fundamental Research Funds for the Central Universities(No.2022SCU12005).
文摘As one of the new generation flexible AC transmission systems(FACTS)devices,the interline power flow controller(IPFC)has the significant advantage of simultaneously regulating the power flow of multiple lines.Nevertheless,how to choose the appropriate location for the IPFC converters has not been discussed thoroughly.To solve this problem,this paper proposes a novel location method for IPFC using entropy theory.To clarify IPFC’s impact on system power flow,its operation mechanism and control strategies of different types of serial converters are discussed.Subsequently,to clarify the system power flow characteristic suitable for device location analysis,the entropy concept is introduced.In this process,the power flow distribution entropy index is used as an optimization index.Using this index as a foundation,the power flow transfer entropy index is also generated and proposed for the IPFC location determination study.Finally,electromechanical electromagnetic hybrid simulations based on ADPSS are implemented for validation.These are tested in a practical power grid with over 800 nodes.A modular multilevel converter(MMC)-based IPFC electromagnetic model is also established for precise verification.The results show that the proposed method can quickly and efficiently complete optimized IPFC location and support IPFC to determine an optimal adjustment in the N-1 fault cases.
基金The authors received specific funding for State Grid Corporation Headquarters Project Support,Key Technologies and Applications of Planning and Decision-Making Based on the Full Cost Chain of the Power Grid,Grant No.5205331800001.
文摘For facing the challenges brought by large-scale renewable energy having access to the system and considering the key technologies of energy Internet,it is very necessary to put forward the location method of distribution network equipment and capacity from the perspective of life cycle cost.Compared with the traditional energy network,the equipment capacity problem of energy interconnected distribution network which involves in electricity network,thermal energy network and natural gas network is comprehensively considered in this paper.On this basis,firstly,the operation architecture of energy interconnected distribution network is designed.Secondly,taking the grid connection location and configuration capacity of key equipment in the system as the control variables and the operation cost of system comprehensive planning in the whole life cycle as the goal,the equipment location and capacity optimization model of energy interconnected distribution network is established.Finally,an IEEE 33 bus energy mutual distribution grid system is taken for example analysis,and the improved chaotic particle swarmoptimization algorithm is used to solve it.The simulation results show that the method proposed in this paper is suitable for the equipment location and capacity planning of energy interconnected distribution network,and it can effectively improve the social and economic benefits of system operation.
基金National Natural Science Foundation of China (40234038).
文摘We have selected 171 near-field records from 391 aftershock records of the Lulong, Hebei Province, earthquake in October 1982 and relocated the hypocenter of 45 aftershocks using the program Hypoinverse. The distribution of aftershocks reveals a set of earthquake faults: a WNW stretching fault truncates two NNE stretching faults. The two branches of faults show the conjugate structure which is often seen in brittle fracture. The NNE stretching faults are connected together. The Luanhe river valley near Lulong developed to a rudiment rift basin surrounded by a series of faults. The fault of Lulong earthquake is a strike-slip fault with tension component. This fault type matches with the activity of Zhangjiakou-Bohai seismic belt (Zhang-Bo belt) and also shows the action of Zhang-Bo belt as a boundary of two secondary active blocks that truncates the NNE fault.
文摘In recent years,Structural Health Monitoring (SHM) has emerged as a new research area in civil engineering.Most existing health monitoring methodologies require direct measurement of input excitation for implementation.However,in many cases,there is no easy way to measure these inputs-or alternatively to externally excite the structure.Therefore,SHM methods based on ambient vibration have become important in civil engineering.In this paper,an approach is proposed based on the Damage Location Vector (DLV) method to handle the ambient vibration case.Here,this flexibility-matrix-based damage localization method is combined with a modal expansion technique to eliminate the need to measure the input excitation.As a by-product of this approach,in addition to determining the location of the damage,an estimate of the damage extent also can be determined.Finally,a numerical example analyzing a truss structure with limited sensors and noisy measurement is provided to verify the efficacy of the proposed approach.
文摘An iteration method for correcting the target coordinates determined by a locating system with a Cartesian array is reported. Under the complex hydrological condition, the method can give the target position not only accurately but also quickly. The preliminary experimental results show that the correction is effective. An application of the method has been completed.
基金supported by the National Basic Research and Development Program of China(973 Program,Grant No.2007CB714105)the National Natural Science Foundation of China(Grant No.50909067)
文摘This paper presents results of model tests for the landslide dam failure of a single dam and cascade dams in a sloping channel. The dams were designed to be regular trapezoid with fine sand. A new measuring method named the labeled line locating method was used to digitalize the captured instantaneous pictures. Under two different inflow discharges, the morphological evolution and the flow patterns during one dam failure and the failure of cascade dams were investigated. The results indicate that when the inflow discharge is large, the deformation pattern of the downstream dam is similar to that of the upstream dam, and both dams are characterized with the overtopping scour throughout the dam failure process. When the inflow discharge is small, the upstream dam is scoured mainly through a sluice slot formed by the longitudinal incision, and the downstream dam is characterized with the overtopping scour. The data set presented in this paper can be used for the validation of numerical models and provide a reference for the flood risk management of cascade landslide dams.