Pub Date : 2014-07-27DOI: 10.1109/PESGM.2014.6939273
Shantanu Kumar, N. Das, J. Muigai, S. Islam
Communication between intelligent electronic devices (IED's) is an important feature of a utility substation automation system based on IEC 61850. Time critical information related to fault and overcurrent, under frequency messages for substation automation system (SAS) and the use of IED's from multiple vendors, has opened up issues related to a reliable protection system within the high voltage substation. Early detection of the delay in data transmission over a Generic Object Oriented Substation Event (GOOSE) network is an important step towards identification of problems associated with the dynamic protection system. It is observed that non critical messages adds up the queuing time and delays in the delivery of the messages which could be an issue in the reliable operation of a protection system. In this paper an Optimized Network Engineering Tool (OPNET) model is created, tested and analysed for a single and double bus configuration in detail for the delay encountered in data transfer within a typical zone substation. In order to understand the delay in transmission of packets, a 132/22kV zone substation model is analysed and results are discussed based on GOOSE communication in an IEC 61850 environment. Further, the delay in communication is compared and analysed between a single and double bus system of a 132/22kV substation to determine the best alternative technique available from protection point of view in a SAS network.
{"title":"Performance evaluation of data transmission in a single and double bus network within the utility substation based on IEC 61850","authors":"Shantanu Kumar, N. Das, J. Muigai, S. Islam","doi":"10.1109/PESGM.2014.6939273","DOIUrl":"https://doi.org/10.1109/PESGM.2014.6939273","url":null,"abstract":"Communication between intelligent electronic devices (IED's) is an important feature of a utility substation automation system based on IEC 61850. Time critical information related to fault and overcurrent, under frequency messages for substation automation system (SAS) and the use of IED's from multiple vendors, has opened up issues related to a reliable protection system within the high voltage substation. Early detection of the delay in data transmission over a Generic Object Oriented Substation Event (GOOSE) network is an important step towards identification of problems associated with the dynamic protection system. It is observed that non critical messages adds up the queuing time and delays in the delivery of the messages which could be an issue in the reliable operation of a protection system. In this paper an Optimized Network Engineering Tool (OPNET) model is created, tested and analysed for a single and double bus configuration in detail for the delay encountered in data transfer within a typical zone substation. In order to understand the delay in transmission of packets, a 132/22kV zone substation model is analysed and results are discussed based on GOOSE communication in an IEC 61850 environment. Further, the delay in communication is compared and analysed between a single and double bus system of a 132/22kV substation to determine the best alternative technique available from protection point of view in a SAS network.","PeriodicalId":149134,"journal":{"name":"2014 IEEE PES General Meeting | Conference & Exposition","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125001910","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 : 2014-07-27DOI: 10.1109/PESGM.2014.6939296
Libo Zhang, Haozhong Cheng, Shenxi Zhang, Pingliang Zeng, L. Yao, M. Bazargan
With the increasing penetration of wind sources, not only the fluctuation of wind power, but also the correlations among wind farms should be considered in power system analysis. Point estimate method is an effective tool for probabilistic analysis. This paper proposed a novel probabilistic power flow(PPF) algorithm that can tackle dependences among nodal power injections. The proposed PPF algorithm extended three-point estimate method by using Nataf transformation which can deal with multi-variables with incomplete information. The advantage of the algorithm is that the correlation can be precisely taken into account and accurate moments of output variables can be obtained. Accuracy and efficiency of the proposed algorithm has been validated by the comparative tests in a modified IEEE RTS-24 system and a modified IEEE 118-bus system.
{"title":"A novel point estimate method for probabilistic power flow considering correlated nodal power","authors":"Libo Zhang, Haozhong Cheng, Shenxi Zhang, Pingliang Zeng, L. Yao, M. Bazargan","doi":"10.1109/PESGM.2014.6939296","DOIUrl":"https://doi.org/10.1109/PESGM.2014.6939296","url":null,"abstract":"With the increasing penetration of wind sources, not only the fluctuation of wind power, but also the correlations among wind farms should be considered in power system analysis. Point estimate method is an effective tool for probabilistic analysis. This paper proposed a novel probabilistic power flow(PPF) algorithm that can tackle dependences among nodal power injections. The proposed PPF algorithm extended three-point estimate method by using Nataf transformation which can deal with multi-variables with incomplete information. The advantage of the algorithm is that the correlation can be precisely taken into account and accurate moments of output variables can be obtained. Accuracy and efficiency of the proposed algorithm has been validated by the comparative tests in a modified IEEE RTS-24 system and a modified IEEE 118-bus system.","PeriodicalId":149134,"journal":{"name":"2014 IEEE PES General Meeting | Conference & Exposition","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125020825","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 : 2014-07-27DOI: 10.1109/PESGM.2014.6938866
V. Perumalla, Qiaoyan Bian, Di Wu, John N. Jiang
A good understanding of the voltage profile of an interconnected power grid is important for supporting the decision on the interconnection of power grids in terms of power quality and power transmission security, especially for developing countries when making interconnection decisions, with a limited amount of expensive voltage compensation devices. In this paper, a statistic method is presented for assessing the change in the system-wide voltage profile before and after the interconnection of large-scale power grids, which provides additional useful information to support the existing interconnection studies. In this method, the skewness and kurtosis are used to characterize the change in the voltage distribution of the non-generation buses before and after the interconnection. Furthermore, a study is presented to show that the skewness and kurtosis may be essential for a statistical analysis of the change in the system-wide voltage profile, as its distribution might be skewed, particularly for the non-generator buses without automatic voltage regulators or other compensation devices. The demonstration of this method is also provided.
{"title":"A study of the voltage distribution for the interconnection of power grids","authors":"V. Perumalla, Qiaoyan Bian, Di Wu, John N. Jiang","doi":"10.1109/PESGM.2014.6938866","DOIUrl":"https://doi.org/10.1109/PESGM.2014.6938866","url":null,"abstract":"A good understanding of the voltage profile of an interconnected power grid is important for supporting the decision on the interconnection of power grids in terms of power quality and power transmission security, especially for developing countries when making interconnection decisions, with a limited amount of expensive voltage compensation devices. In this paper, a statistic method is presented for assessing the change in the system-wide voltage profile before and after the interconnection of large-scale power grids, which provides additional useful information to support the existing interconnection studies. In this method, the skewness and kurtosis are used to characterize the change in the voltage distribution of the non-generation buses before and after the interconnection. Furthermore, a study is presented to show that the skewness and kurtosis may be essential for a statistical analysis of the change in the system-wide voltage profile, as its distribution might be skewed, particularly for the non-generator buses without automatic voltage regulators or other compensation devices. The demonstration of this method is also provided.","PeriodicalId":149134,"journal":{"name":"2014 IEEE PES General Meeting | Conference & Exposition","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125807275","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 : 2014-07-27DOI: 10.1109/PESGM.2014.6939404
Mengshi Li, T. Ji, Qinghua Wu, P. Wu
This paper aims to solve an economic dispatch problem concerning wind power using a Bacterial Swarm Algorithm (BSA). The massive installation of the wind turbines in power system presents a challenge for the conventional economic dispatch. With increasing wind power penetration, the ramp capability of wind farms correlates with the uncertain wind speed rather than a fix ratio as conventional generators. Therefore, the ramp constraints of the economic dispatch can be extended to a probability which is related to the wind speed. In order to solve the constrained optimization problem, this paper employs the BSA to reduce the fuel cost by selecting suitable control variables governing the power systems. The proposed method has been evaluated using an IEEE 30-bus test system. Simulation results indicate that the proposed method significantly reduces the fuel cost and satisfies the ramp constraints.
{"title":"Economic dispatch with ramp constraints concerning wind power uncertainty","authors":"Mengshi Li, T. Ji, Qinghua Wu, P. Wu","doi":"10.1109/PESGM.2014.6939404","DOIUrl":"https://doi.org/10.1109/PESGM.2014.6939404","url":null,"abstract":"This paper aims to solve an economic dispatch problem concerning wind power using a Bacterial Swarm Algorithm (BSA). The massive installation of the wind turbines in power system presents a challenge for the conventional economic dispatch. With increasing wind power penetration, the ramp capability of wind farms correlates with the uncertain wind speed rather than a fix ratio as conventional generators. Therefore, the ramp constraints of the economic dispatch can be extended to a probability which is related to the wind speed. In order to solve the constrained optimization problem, this paper employs the BSA to reduce the fuel cost by selecting suitable control variables governing the power systems. The proposed method has been evaluated using an IEEE 30-bus test system. Simulation results indicate that the proposed method significantly reduces the fuel cost and satisfies the ramp constraints.","PeriodicalId":149134,"journal":{"name":"2014 IEEE PES General Meeting | Conference & Exposition","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125861440","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 : 2014-07-27DOI: 10.1109/PESGM.2014.6939210
Zhixin Miao
Type 3 wind generators in series compensated networks could lead to subsynchronous resonances (SSR). Previous research focuses on balanced operation only. In this paper, impact of unbalance on Type 3 wind energy systems is investigated in two aspects: (i) impact on electric resonances and (ii) impact on torsional resonances. In the first aspect, impedance models of the system in DQ domain and phase domain are developed. Particularly, negative sequence impedances are examined. Nyquist stability criterion is applied to detect possible resonances. In the second aspect, transfer functions of the electromagnetic torque versus the rotating speed due to negative sequence components are developed. The impact of negative sequence components on electromechanical damping is then analyzed. The analysis results are verified by time-domain simulation results.
{"title":"Impact of unbalance on electrical and torsional resonances in power electronic interfaced wind energy systems","authors":"Zhixin Miao","doi":"10.1109/PESGM.2014.6939210","DOIUrl":"https://doi.org/10.1109/PESGM.2014.6939210","url":null,"abstract":"Type 3 wind generators in series compensated networks could lead to subsynchronous resonances (SSR). Previous research focuses on balanced operation only. In this paper, impact of unbalance on Type 3 wind energy systems is investigated in two aspects: (i) impact on electric resonances and (ii) impact on torsional resonances. In the first aspect, impedance models of the system in DQ domain and phase domain are developed. Particularly, negative sequence impedances are examined. Nyquist stability criterion is applied to detect possible resonances. In the second aspect, transfer functions of the electromagnetic torque versus the rotating speed due to negative sequence components are developed. The impact of negative sequence components on electromechanical damping is then analyzed. The analysis results are verified by time-domain simulation results.","PeriodicalId":149134,"journal":{"name":"2014 IEEE PES General Meeting | Conference & Exposition","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123432933","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 : 2014-07-27DOI: 10.1109/PESGM.2014.6939466
Yunhui Huang, Xiaoming Yuan, Jiabing Hu
In this paper, effect of reactive power control (RPC) on the stability of DC-link voltage control (DVC) in voltage source converter (VSC) when attached to weak grid is investigated. In weak grid, disturbance in DVC leads variations in terminal voltage and makes RPC respond. In turn, RPC contributes to power output variation and influences DVC. RPC behaves as a lagging regulator for DVC and results in lagging active power output. Referencing to stability analysis theory for synchronous machine, damping and restoring components for DVC are proposed. Stability of DVC affected by RPC is analyzed by evaluating the influence of RPC on damping and restoring components. Additional damping component provided by RPC will become smaller with reduction of grid strength. In addition, when the bandwidth of RPC is close to that of DVC, effect of RPC on DVC is in maximum extent. The time-domain model of 1.5-MW full-scale wind turbine was built in Matlab/Simulink and simulation results validate the analysis above.
{"title":"Effect of reactive power control on stability of DC-link voltage control in VSC connected to weak grid","authors":"Yunhui Huang, Xiaoming Yuan, Jiabing Hu","doi":"10.1109/PESGM.2014.6939466","DOIUrl":"https://doi.org/10.1109/PESGM.2014.6939466","url":null,"abstract":"In this paper, effect of reactive power control (RPC) on the stability of DC-link voltage control (DVC) in voltage source converter (VSC) when attached to weak grid is investigated. In weak grid, disturbance in DVC leads variations in terminal voltage and makes RPC respond. In turn, RPC contributes to power output variation and influences DVC. RPC behaves as a lagging regulator for DVC and results in lagging active power output. Referencing to stability analysis theory for synchronous machine, damping and restoring components for DVC are proposed. Stability of DVC affected by RPC is analyzed by evaluating the influence of RPC on damping and restoring components. Additional damping component provided by RPC will become smaller with reduction of grid strength. In addition, when the bandwidth of RPC is close to that of DVC, effect of RPC on DVC is in maximum extent. The time-domain model of 1.5-MW full-scale wind turbine was built in Matlab/Simulink and simulation results validate the analysis above.","PeriodicalId":149134,"journal":{"name":"2014 IEEE PES General Meeting | Conference & Exposition","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125513204","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 : 2014-07-27DOI: 10.1109/PESGM.2014.6939551
I. Parvez, Arif Islam, F. Kaleem
In the key management-based security scheme of Advanced Metering Infrastructure (AMI), it is assumed that the established third party and the links between smart meter and the third party are fully trusted. But in wired/wireless communication, man-in-the middle can interfere, and the monitors and controls in the system can expose its vulnerability. Because of this, we propose a security scheme based on two independent and partially trusted but simple servers, which includes two-level encryption without increasing packet overhead. One server (master) manages the data encryption between the meter to ES (energy supplier) and the other server manages randomized data transfer. We also propose a simple node-to-node authentication method based on electromagnetic signal strength.
{"title":"A key management-based two-level encryption method for AMI","authors":"I. Parvez, Arif Islam, F. Kaleem","doi":"10.1109/PESGM.2014.6939551","DOIUrl":"https://doi.org/10.1109/PESGM.2014.6939551","url":null,"abstract":"In the key management-based security scheme of Advanced Metering Infrastructure (AMI), it is assumed that the established third party and the links between smart meter and the third party are fully trusted. But in wired/wireless communication, man-in-the middle can interfere, and the monitors and controls in the system can expose its vulnerability. Because of this, we propose a security scheme based on two independent and partially trusted but simple servers, which includes two-level encryption without increasing packet overhead. One server (master) manages the data encryption between the meter to ES (energy supplier) and the other server manages randomized data transfer. We also propose a simple node-to-node authentication method based on electromagnetic signal strength.","PeriodicalId":149134,"journal":{"name":"2014 IEEE PES General Meeting | Conference & Exposition","volume":"82 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126615940","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 : 2014-07-27DOI: 10.1109/PESGM.2014.6939255
H. Saad, S. Dennetière, J. Mahseredjian, P. Delarue, X. Guillaud, J. Peralta, S. Nguefeu
Summary form only given. Modular multilevel converters (MMCs) may contain numerous IGBTs. The modeling of such converters for electromagnetic transient type (EMT-type) simulations is complex. Detailed models used in MMC-HVDC simulations may require very large computing times. Simplified and averaged models have been proposed in the past to overcome this problem. In this paper existing averaged and simplified models are improved in order to increase their range of applications. The models are compared and analyzed for different transient events on a MMC-HVDC system.
{"title":"Modular multilevel converter models for electromagnetic transients","authors":"H. Saad, S. Dennetière, J. Mahseredjian, P. Delarue, X. Guillaud, J. Peralta, S. Nguefeu","doi":"10.1109/PESGM.2014.6939255","DOIUrl":"https://doi.org/10.1109/PESGM.2014.6939255","url":null,"abstract":"Summary form only given. Modular multilevel converters (MMCs) may contain numerous IGBTs. The modeling of such converters for electromagnetic transient type (EMT-type) simulations is complex. Detailed models used in MMC-HVDC simulations may require very large computing times. Simplified and averaged models have been proposed in the past to overcome this problem. In this paper existing averaged and simplified models are improved in order to increase their range of applications. The models are compared and analyzed for different transient events on a MMC-HVDC system.","PeriodicalId":149134,"journal":{"name":"2014 IEEE PES General Meeting | Conference & Exposition","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126738579","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 : 2014-07-27DOI: 10.1109/PESGM.2014.6938947
Yongli Zhu, Songtao Lu
In this paper, a Blind-source separation method, i.e. Independent Component Analysis (ICA) is used for disaggregating the substation load profile into different patterns, i.e. residential and commercial groups. The smart meter data from a down town substation has been used. Principle Component Analysis (PCA) is applied for data reduction. Wavelet analysis is used to extract the trend signal from the original load profile as inputs for the ICA routine. Final results verify the effectiveness of this load profile disaggregation approach.
{"title":"Load profile disaggregation by Blind source separation: A wavelets-assisted independent component analysis approach","authors":"Yongli Zhu, Songtao Lu","doi":"10.1109/PESGM.2014.6938947","DOIUrl":"https://doi.org/10.1109/PESGM.2014.6938947","url":null,"abstract":"In this paper, a Blind-source separation method, i.e. Independent Component Analysis (ICA) is used for disaggregating the substation load profile into different patterns, i.e. residential and commercial groups. The smart meter data from a down town substation has been used. Principle Component Analysis (PCA) is applied for data reduction. Wavelet analysis is used to extract the trend signal from the original load profile as inputs for the ICA routine. Final results verify the effectiveness of this load profile disaggregation approach.","PeriodicalId":149134,"journal":{"name":"2014 IEEE PES General Meeting | Conference & Exposition","volume":"286 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116407172","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 : 2014-07-27DOI: 10.1109/PESGM.2014.6938811
V. M. Murthy Balijepalli, S. Khaparde
Zero Net Energy Buildings (ZNEB) are most opted for effective energy conservation measures. The major milestone in building ZNEB is the large number of parameters on which energy consumption depends. This paper studies the effect of cost related parameters on optimization of ZNEB. Effect of cost of appliances on the optimized parameters is investigated. Opensource softwares are explored for the simulation studies and extended modules are built for integrating retail tariffs/OpenEI to the engines. Simulations are carried out with different utility rates and tariff system, and a comparison is made. ZNEB potential in developing countries like India is further discussed and observations are presented.
{"title":"Effect of cost related parameters on optimization of Zero Net Energy Buildings","authors":"V. M. Murthy Balijepalli, S. Khaparde","doi":"10.1109/PESGM.2014.6938811","DOIUrl":"https://doi.org/10.1109/PESGM.2014.6938811","url":null,"abstract":"Zero Net Energy Buildings (ZNEB) are most opted for effective energy conservation measures. The major milestone in building ZNEB is the large number of parameters on which energy consumption depends. This paper studies the effect of cost related parameters on optimization of ZNEB. Effect of cost of appliances on the optimized parameters is investigated. Opensource softwares are explored for the simulation studies and extended modules are built for integrating retail tariffs/OpenEI to the engines. Simulations are carried out with different utility rates and tariff system, and a comparison is made. ZNEB potential in developing countries like India is further discussed and observations are presented.","PeriodicalId":149134,"journal":{"name":"2014 IEEE PES General Meeting | Conference & Exposition","volume":"101 6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116519581","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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