Pub Date : 2012-05-21DOI: 10.1109/ISGT-ASIA.2012.6303143
Wang Qinghao, Zhang Hua, L. Guobin, Zhang Wenguang, Li Na, Yang Ying, Ma Guohai
The paper describes grounding wire of transformer core becomes flexible, leads to the core produce suspended potential, results in discharge, the discharge current is generated power loss in the ground copper and the ground lead of the core, and causes transformer oil chromatographic analysis data anomalies. Put forward when the total hydrocarbons increases but not “out of limits”, the searching method for fault reasons, steps and precautions, noting that the external ground wire of transformer core is loosing also belongs to the category of the core faults.
{"title":"Transformer core accidents caused by loosing ground wire","authors":"Wang Qinghao, Zhang Hua, L. Guobin, Zhang Wenguang, Li Na, Yang Ying, Ma Guohai","doi":"10.1109/ISGT-ASIA.2012.6303143","DOIUrl":"https://doi.org/10.1109/ISGT-ASIA.2012.6303143","url":null,"abstract":"The paper describes grounding wire of transformer core becomes flexible, leads to the core produce suspended potential, results in discharge, the discharge current is generated power loss in the ground copper and the ground lead of the core, and causes transformer oil chromatographic analysis data anomalies. Put forward when the total hydrocarbons increases but not “out of limits”, the searching method for fault reasons, steps and precautions, noting that the external ground wire of transformer core is loosing also belongs to the category of the core faults.","PeriodicalId":330758,"journal":{"name":"IEEE PES Innovative Smart Grid Technologies","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130549871","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-05-21DOI: 10.1109/ISGT-ASIA.2012.6303121
Yanan Wang, Xinran Li, Yang Liu, Lin Zhu
The accurate degree of power system dynamic simulation is directly related to the stable operation of power system, while the accuracy of load models have a direct influence on simulation results and final decisions. Based on PSASP/UPI, this paper develops an interface method linking the model to the transient stability program. By the transient stability program, load model can be linked to power system for dynamic simulation. Then the design idea of user program and realization steps of dynamic simulation are described. The interface principles between user program and transient stability program are showed. This paper connects induction motor synthetic load model with distribution network lumping to EPRI-36 bus system in PSASP for dynamic simulation, and the calculation results prove the correctness of the user program interface method. Therefore, the way to link load models to power system for dynamic simulation based on PSASP/UPI can be concluded.
{"title":"Research on dynamic simulation of the induction motor synthetic load model based on PSASP/UPI","authors":"Yanan Wang, Xinran Li, Yang Liu, Lin Zhu","doi":"10.1109/ISGT-ASIA.2012.6303121","DOIUrl":"https://doi.org/10.1109/ISGT-ASIA.2012.6303121","url":null,"abstract":"The accurate degree of power system dynamic simulation is directly related to the stable operation of power system, while the accuracy of load models have a direct influence on simulation results and final decisions. Based on PSASP/UPI, this paper develops an interface method linking the model to the transient stability program. By the transient stability program, load model can be linked to power system for dynamic simulation. Then the design idea of user program and realization steps of dynamic simulation are described. The interface principles between user program and transient stability program are showed. This paper connects induction motor synthetic load model with distribution network lumping to EPRI-36 bus system in PSASP for dynamic simulation, and the calculation results prove the correctness of the user program interface method. Therefore, the way to link load models to power system for dynamic simulation based on PSASP/UPI can be concluded.","PeriodicalId":330758,"journal":{"name":"IEEE PES Innovative Smart Grid Technologies","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130576281","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-05-21DOI: 10.1109/ISGT-ASIA.2012.6303372
Shouxiang Wang, N. Zhang, Zuyi Li, M. Shahidehpour
With the rapid development of smart grid, the large scale vehicle-to-grid (V2G) electric vehicles (EVs) will been widely applied. However, the interaction between EVs and the power grid will bring many challenges. In order to lighten the adverse influence on the grid operation, the regional EV load should be estimated in advance. By thoroughly considering the impact factors of regional EV load on the gird, this paper presents a methodology to determine the regional EV load. Monte Carol simulation algorithm is adopted to draw the random numbers of impact factors and to achieve the simulation of EV load curve. Three kinds of EV load models are built and simulated including uncontrolled charging model, controlled charging model and controlled charging/discharging model. The impact of three different EV load models on the grid load curve and on the load rate and peak-valley difference of the grid is given in this paper. And the impact of different scale of EVs on the grid is also discussed. The EVs in Qingdao Economic and Technological Development Zone (QETDZ) in Qingdao city, Shandong Province, China are taken as an example to analyze the impact on the grid of different regional EV load models. The simulation results show that the three EV load models built in this paper are helpful to study the impact on the power grid and have a potential value in practical applications.
{"title":"Modeling and impact analysis of large scale V2G electric vehicles on the power grid","authors":"Shouxiang Wang, N. Zhang, Zuyi Li, M. Shahidehpour","doi":"10.1109/ISGT-ASIA.2012.6303372","DOIUrl":"https://doi.org/10.1109/ISGT-ASIA.2012.6303372","url":null,"abstract":"With the rapid development of smart grid, the large scale vehicle-to-grid (V2G) electric vehicles (EVs) will been widely applied. However, the interaction between EVs and the power grid will bring many challenges. In order to lighten the adverse influence on the grid operation, the regional EV load should be estimated in advance. By thoroughly considering the impact factors of regional EV load on the gird, this paper presents a methodology to determine the regional EV load. Monte Carol simulation algorithm is adopted to draw the random numbers of impact factors and to achieve the simulation of EV load curve. Three kinds of EV load models are built and simulated including uncontrolled charging model, controlled charging model and controlled charging/discharging model. The impact of three different EV load models on the grid load curve and on the load rate and peak-valley difference of the grid is given in this paper. And the impact of different scale of EVs on the grid is also discussed. The EVs in Qingdao Economic and Technological Development Zone (QETDZ) in Qingdao city, Shandong Province, China are taken as an example to analyze the impact on the grid of different regional EV load models. The simulation results show that the three EV load models built in this paper are helpful to study the impact on the power grid and have a potential value in practical applications.","PeriodicalId":330758,"journal":{"name":"IEEE PES Innovative Smart Grid Technologies","volume":"67 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130636919","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-05-21DOI: 10.1109/ISGT-ASIA.2012.6303260
A. Ma, Z. S. Zhang
This article uses the finite element method to analysis and calculates the electric field intensity of 500kV power transformer's HV winding. Through analysis and research the power transformer, the article has simplified the model of power transformer. Using ANSYS software establishes 2-D modeling of 500kV power transformer to analysis and conducted on the model mesh. Through analysis and understanding the power transformer's data, the boundary conditions are gotten which should be imposed on the various parts of the model. This article gets clear electric potential and electric field distribution by using finite element method to calculate the electric field intensity. The structure of power transformer has been optimized after analyzing the electric field distribution. Changing the radius of the electrostatic ring can decrease the maximum electric field intensity value of insulating layer surface, and the electrical field intensity will be more evenly distributed in the whole domain in power transformer, which is very important to design reasonable insulation structure for power transformer.
{"title":"End insulation electric field analysis and design optimization of 500kV power transformer based on ANSYS","authors":"A. Ma, Z. S. Zhang","doi":"10.1109/ISGT-ASIA.2012.6303260","DOIUrl":"https://doi.org/10.1109/ISGT-ASIA.2012.6303260","url":null,"abstract":"This article uses the finite element method to analysis and calculates the electric field intensity of 500kV power transformer's HV winding. Through analysis and research the power transformer, the article has simplified the model of power transformer. Using ANSYS software establishes 2-D modeling of 500kV power transformer to analysis and conducted on the model mesh. Through analysis and understanding the power transformer's data, the boundary conditions are gotten which should be imposed on the various parts of the model. This article gets clear electric potential and electric field distribution by using finite element method to calculate the electric field intensity. The structure of power transformer has been optimized after analyzing the electric field distribution. Changing the radius of the electrostatic ring can decrease the maximum electric field intensity value of insulating layer surface, and the electrical field intensity will be more evenly distributed in the whole domain in power transformer, which is very important to design reasonable insulation structure for power transformer.","PeriodicalId":330758,"journal":{"name":"IEEE PES Innovative Smart Grid Technologies","volume":"117 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123306911","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-05-21DOI: 10.1109/ISGT-ASIA.2012.6303146
Jing He, Qing Li, Shiyao Qin, Ruiming Wang
As the increasing of installed capability of wind power in power system, the dynamic wind turbine models are required for wind turbine and wind farm stability assessment. For this reason, the wind turbine models have to be simulated accurately compare to the wind turbine operation behavior especially during grid fault. An accurate DFIG wind turbine dynamic model is presented. For low voltage ride through (LVRT) simulation, the 5th and 3th order generator model, including converter with crowbar and chopper, pitch angle controller, drive train model are analyzed. Simulations are carried out to analyze the model structure and parameters influence to LVRT behavior. The models are simulated, and validated with the wind turbine LVRT field-test data. Validation results show the accuracy of the model.
{"title":"DFIG wind turbine modeling and validation for LVRT behavior","authors":"Jing He, Qing Li, Shiyao Qin, Ruiming Wang","doi":"10.1109/ISGT-ASIA.2012.6303146","DOIUrl":"https://doi.org/10.1109/ISGT-ASIA.2012.6303146","url":null,"abstract":"As the increasing of installed capability of wind power in power system, the dynamic wind turbine models are required for wind turbine and wind farm stability assessment. For this reason, the wind turbine models have to be simulated accurately compare to the wind turbine operation behavior especially during grid fault. An accurate DFIG wind turbine dynamic model is presented. For low voltage ride through (LVRT) simulation, the 5th and 3th order generator model, including converter with crowbar and chopper, pitch angle controller, drive train model are analyzed. Simulations are carried out to analyze the model structure and parameters influence to LVRT behavior. The models are simulated, and validated with the wind turbine LVRT field-test data. Validation results show the accuracy of the model.","PeriodicalId":330758,"journal":{"name":"IEEE PES Innovative Smart Grid Technologies","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114825986","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Conventional Optimal Power Flow (OPF) minimizes line loss snapshot by controlling generation output and transformer tap position. Distributed energy storage system (DESS) that locates close to load can provide more flexible and effective control to reduce overall line loss. A dynamic optimal power flow (DOPF) method considering energy storage units is adopted to model and analyze line loss reduction by DESS. Tests are performed to validate the DOPF model and show the effectiveness of line loss reduction by DESS.
{"title":"Line loss reduction with distributed energy storage systems","authors":"X. Zhang, Feng Gao, Xinjie Lv, Hairong Lv, Qiming Tian, Junhua Ma, Wenjun Yin, Jin Dong","doi":"10.1109/ISGT-ASIA.2012.6303333","DOIUrl":"https://doi.org/10.1109/ISGT-ASIA.2012.6303333","url":null,"abstract":"Conventional Optimal Power Flow (OPF) minimizes line loss snapshot by controlling generation output and transformer tap position. Distributed energy storage system (DESS) that locates close to load can provide more flexible and effective control to reduce overall line loss. A dynamic optimal power flow (DOPF) method considering energy storage units is adopted to model and analyze line loss reduction by DESS. Tests are performed to validate the DOPF model and show the effectiveness of line loss reduction by DESS.","PeriodicalId":330758,"journal":{"name":"IEEE PES Innovative Smart Grid Technologies","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124320514","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-05-21DOI: 10.1109/ISGT-ASIA.2012.6303132
L. Zhang, A. Abur
Bad measurements are usually detected and identified by normalized measurement residual test through state estimators. This function relies on the accurate measurement weight assigned according to historical data. Since such information may not be available for new meters such as phasor measurement units (PMUs), a weight tuning algorithm for PMUs has been developed in a previous work. This paper investigates impact of the tuning algorithm on bad data detection of PMU measurements. It proposes a systematic method to improve the robustness of error detection and identification for PMU measurements. Simulations in IEEE 14-bus system are used to illustrate the benefits of suggested approach.
{"title":"Impact of tuning on bad data detection of PMU measurements","authors":"L. Zhang, A. Abur","doi":"10.1109/ISGT-ASIA.2012.6303132","DOIUrl":"https://doi.org/10.1109/ISGT-ASIA.2012.6303132","url":null,"abstract":"Bad measurements are usually detected and identified by normalized measurement residual test through state estimators. This function relies on the accurate measurement weight assigned according to historical data. Since such information may not be available for new meters such as phasor measurement units (PMUs), a weight tuning algorithm for PMUs has been developed in a previous work. This paper investigates impact of the tuning algorithm on bad data detection of PMU measurements. It proposes a systematic method to improve the robustness of error detection and identification for PMU measurements. Simulations in IEEE 14-bus system are used to illustrate the benefits of suggested approach.","PeriodicalId":330758,"journal":{"name":"IEEE PES Innovative Smart Grid Technologies","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127981635","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-05-21DOI: 10.1109/ISGT-ASIA.2012.6303214
Z. Chunyan, Gan Jinxing, Nie Dexin, Du Zhenbo, Tang Zhenpeng, Deng Xiao-qiang
This paper mainly discusses the mechanism for FRA method on bushing insulation detection. It builds several RC models of the bushing instruction in MATLAB, as well as does some simulation work to observe the change of the FRA curve with different parameters. It also takes the influence of the valve wire into consider and get some useful conclusions. Simulation results show that the obvious indentation in the FRA curve will appear when the bushing has some insulation defects. The sum and change state of the indentation in FRA curve is related to the degree and relaxation polarization of the insulation defects of the bushing. It is found that the simulation and on-spot detection curves have tallies with each other, which verifies the feasibility of FRA method in this field.
{"title":"Insulation status detection on the high voltage bushing by FRA method","authors":"Z. Chunyan, Gan Jinxing, Nie Dexin, Du Zhenbo, Tang Zhenpeng, Deng Xiao-qiang","doi":"10.1109/ISGT-ASIA.2012.6303214","DOIUrl":"https://doi.org/10.1109/ISGT-ASIA.2012.6303214","url":null,"abstract":"This paper mainly discusses the mechanism for FRA method on bushing insulation detection. It builds several RC models of the bushing instruction in MATLAB, as well as does some simulation work to observe the change of the FRA curve with different parameters. It also takes the influence of the valve wire into consider and get some useful conclusions. Simulation results show that the obvious indentation in the FRA curve will appear when the bushing has some insulation defects. The sum and change state of the indentation in FRA curve is related to the degree and relaxation polarization of the insulation defects of the bushing. It is found that the simulation and on-spot detection curves have tallies with each other, which verifies the feasibility of FRA method in this field.","PeriodicalId":330758,"journal":{"name":"IEEE PES Innovative Smart Grid Technologies","volume":"73 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121711226","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-05-21DOI: 10.1109/ISGT-ASIA.2012.6303352
Zhaofei Li, Qing Chen, Zhanjun Gao, Dezhen Nie
In substations of power system, 3/2 connections are used commonly whose protective relay configurations are complex. There is lots of information when a fault occurs, especially when protective relays and circuit breakers fail to work. How to determine the fault component is particularly intricate. According to above features of 3/2 breaker schemes, this paper put forwards a new fault diagnosis method based on fuzzy Petri nets and associated tree. Markov state-space method is used to calculate the reliability of protective relaying system. This paper defines and corrects the action reality of the main protection, backup protection and breaker failure protection. The concept of group is introduced to define the associated tree, which is used to describe the topology of the 3/2 connection. The associated tree is created to identify every possible fault primary component according to breaker-primary component association. Depending on the relationship of protective relays, a fault diagnosis model based on fuzzy Petri nets is established to determine the faulty components and the fault type quickly and accurately. Finally, by forward and backward reasoning, the malfunctioned circuit breakers and protective relays, even the missing and/or false alarms can be identified. The simulation results given in this paper illustrate that this fault diagnosis method can make a rapid diagnosis and give an accurate evaluation about the 3/2 breaker scheme faults.
{"title":"Fault diagnosis of 3/2 connection","authors":"Zhaofei Li, Qing Chen, Zhanjun Gao, Dezhen Nie","doi":"10.1109/ISGT-ASIA.2012.6303352","DOIUrl":"https://doi.org/10.1109/ISGT-ASIA.2012.6303352","url":null,"abstract":"In substations of power system, 3/2 connections are used commonly whose protective relay configurations are complex. There is lots of information when a fault occurs, especially when protective relays and circuit breakers fail to work. How to determine the fault component is particularly intricate. According to above features of 3/2 breaker schemes, this paper put forwards a new fault diagnosis method based on fuzzy Petri nets and associated tree. Markov state-space method is used to calculate the reliability of protective relaying system. This paper defines and corrects the action reality of the main protection, backup protection and breaker failure protection. The concept of group is introduced to define the associated tree, which is used to describe the topology of the 3/2 connection. The associated tree is created to identify every possible fault primary component according to breaker-primary component association. Depending on the relationship of protective relays, a fault diagnosis model based on fuzzy Petri nets is established to determine the faulty components and the fault type quickly and accurately. Finally, by forward and backward reasoning, the malfunctioned circuit breakers and protective relays, even the missing and/or false alarms can be identified. The simulation results given in this paper illustrate that this fault diagnosis method can make a rapid diagnosis and give an accurate evaluation about the 3/2 breaker scheme faults.","PeriodicalId":330758,"journal":{"name":"IEEE PES Innovative Smart Grid Technologies","volume":"67 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115905208","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-05-21DOI: 10.1109/ISGT-ASIA.2012.6303286
Yanyan Cui, M. Zhao, Qin Li, Jie Zhu
In view of the wide configuration range of the capacity of distribution transformer in residential districts, and the lack of actual data and accurate design basis, the load characteristics of urban ordinary residential housing and principle of power supply facilities configuration are researched. Firstly, the type of the residential district investigated is decided, 4117 households of three residential districts are selected as research object, large-scale and real-time load sample data which is up to three years is collected by using the smart meters. Secondly, the typical residential load characteristics are obtained by analyzing and summarizing the data collected. In the end, the load characteristics obtained are further analyzed and calculated to configure the power supply facilities of the planning residential district.
{"title":"Research on load characteristics of urban ordinary residential housing and principle of power supply facilities configuration","authors":"Yanyan Cui, M. Zhao, Qin Li, Jie Zhu","doi":"10.1109/ISGT-ASIA.2012.6303286","DOIUrl":"https://doi.org/10.1109/ISGT-ASIA.2012.6303286","url":null,"abstract":"In view of the wide configuration range of the capacity of distribution transformer in residential districts, and the lack of actual data and accurate design basis, the load characteristics of urban ordinary residential housing and principle of power supply facilities configuration are researched. Firstly, the type of the residential district investigated is decided, 4117 households of three residential districts are selected as research object, large-scale and real-time load sample data which is up to three years is collected by using the smart meters. Secondly, the typical residential load characteristics are obtained by analyzing and summarizing the data collected. In the end, the load characteristics obtained are further analyzed and calculated to configure the power supply facilities of the planning residential district.","PeriodicalId":330758,"journal":{"name":"IEEE PES Innovative Smart Grid Technologies","volume":"261 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115962011","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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