Pub Date : 2009-07-26DOI: 10.1109/PES.2009.5275824
X.D. Liu, Ying Li, Z.J. Liu, Z. Huang, Y. Miao, Qi Jun, Q. Jiang, W.H. Chen
A novel fast method based on phasor measurement units (PMU) measurements for transient stability prediction is presented in this paper. The method simulates various faults of a system off-line and records all rotor angle trajectories. Then a characteristic trajectory set is obtained for each generator using Hierarchical Cluster Algorithm (HCA) and a perturbed trajectory standard pattern database (PTSPD) is generated. By calculating the Euclidean distance between the trajectory uploaded by PMU and each characteristic trajectory in the PTSPD, the rotor angle trajectory can be predicted by the most similar characteristic trajectory. Thus the transient stability is predicted. Taking the New England test system for example, the effectiveness of the proposed method is proved.
{"title":"A novel fast transient stability prediction method based on PMU","authors":"X.D. Liu, Ying Li, Z.J. Liu, Z. Huang, Y. Miao, Qi Jun, Q. Jiang, W.H. Chen","doi":"10.1109/PES.2009.5275824","DOIUrl":"https://doi.org/10.1109/PES.2009.5275824","url":null,"abstract":"A novel fast method based on phasor measurement units (PMU) measurements for transient stability prediction is presented in this paper. The method simulates various faults of a system off-line and records all rotor angle trajectories. Then a characteristic trajectory set is obtained for each generator using Hierarchical Cluster Algorithm (HCA) and a perturbed trajectory standard pattern database (PTSPD) is generated. By calculating the Euclidean distance between the trajectory uploaded by PMU and each characteristic trajectory in the PTSPD, the rotor angle trajectory can be predicted by the most similar characteristic trajectory. Thus the transient stability is predicted. Taking the New England test system for example, the effectiveness of the proposed method is proved.","PeriodicalId":258632,"journal":{"name":"2009 IEEE Power & Energy Society General Meeting","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131616697","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 : 2009-07-26DOI: 10.1109/PES.2009.5275363
Yi Yang, D. Divan, R. Harley, T. Habetler
The task of monitoring asset status and optimizing asset utilization for the power grid, given millions of assets and hundreds of thousands of miles of power lines distributed over millions of square miles, seems costly, if not impossible. Given the traditionally high cost of sensing and communications, the current grid has minimal ‘smarts’ with much of the intelligence located at major substations. Dramatic reductions in sensor, computing and communications costs, coupled with significant performance enhancements has increased the possibility of realizing widely and massively power line sensor networks (PLSNs) to monitor utility asset status. A NSF funded a project, “Power Line Sensornet for Enhancing Line Reliability and Utilization”, has led to the development of an integrated multi-task power line sensor (PLS) module. This paper mainly addresses the design and implementation issues for such a sensor module.
{"title":"Design and implementation of power line sensornet for overhead transmission lines","authors":"Yi Yang, D. Divan, R. Harley, T. Habetler","doi":"10.1109/PES.2009.5275363","DOIUrl":"https://doi.org/10.1109/PES.2009.5275363","url":null,"abstract":"The task of monitoring asset status and optimizing asset utilization for the power grid, given millions of assets and hundreds of thousands of miles of power lines distributed over millions of square miles, seems costly, if not impossible. Given the traditionally high cost of sensing and communications, the current grid has minimal ‘smarts’ with much of the intelligence located at major substations. Dramatic reductions in sensor, computing and communications costs, coupled with significant performance enhancements has increased the possibility of realizing widely and massively power line sensor networks (PLSNs) to monitor utility asset status. A NSF funded a project, “Power Line Sensornet for Enhancing Line Reliability and Utilization”, has led to the development of an integrated multi-task power line sensor (PLS) module. This paper mainly addresses the design and implementation issues for such a sensor module.","PeriodicalId":258632,"journal":{"name":"2009 IEEE Power & Energy Society General Meeting","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128929385","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 : 2009-07-26DOI: 10.1109/PES.2009.5275557
S. Kucuksari, G. Karady
The development of Intelligent Electronic Devices (IED) have increased the use of digital protection systems, in which the digitized signals replaced the usage of conventional analog signals. The digitized signals are generated at electronic instrument transformers and they are transferred to protection systems over a process bus based on IEC 61850-9-2 standard. This transferring process between electronic instrument transformers and protection systems requires a detailed performance evaluation, analysis, and compatibility of the two different systems, since various vendors' instrument transformers and relays are aimed to be connected. This paper presents a developed test facility for all-digital protection system performance evaluations. Typical power system faults are regenerated with the facility and the performance of the digital systems are investigated. The compatibility of an optical current transformer and a digital relay is analyzed. Digital relay's inverse time delay characteristics are obtained. Results show that all-digital systems provided by different manufacturers can work together and are suitable to protect power systems where protection is needed.
{"title":"Development of test facility for compatibility and performance testing of all-digital protection systems connected to IEC 61850-9-2 standard","authors":"S. Kucuksari, G. Karady","doi":"10.1109/PES.2009.5275557","DOIUrl":"https://doi.org/10.1109/PES.2009.5275557","url":null,"abstract":"The development of Intelligent Electronic Devices (IED) have increased the use of digital protection systems, in which the digitized signals replaced the usage of conventional analog signals. The digitized signals are generated at electronic instrument transformers and they are transferred to protection systems over a process bus based on IEC 61850-9-2 standard. This transferring process between electronic instrument transformers and protection systems requires a detailed performance evaluation, analysis, and compatibility of the two different systems, since various vendors' instrument transformers and relays are aimed to be connected. This paper presents a developed test facility for all-digital protection system performance evaluations. Typical power system faults are regenerated with the facility and the performance of the digital systems are investigated. The compatibility of an optical current transformer and a digital relay is analyzed. Digital relay's inverse time delay characteristics are obtained. Results show that all-digital systems provided by different manufacturers can work together and are suitable to protect power systems where protection is needed.","PeriodicalId":258632,"journal":{"name":"2009 IEEE Power & Energy Society General Meeting","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130765417","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 : 2009-07-26DOI: 10.1109/PES.2009.5275907
U. Kerin, E. Lerch, G. Bizjak
In this paper a concept of quantifying small signal security of power systems is introduced. The concept includes employment of a security index identifying system oscillation modes of insufficient characteristics. If referred to a security constraint the index quantifies mode security and if applied in sensitivity study it gives mode security variation in respect to changes in the system. The concept is applied in a study case considering model of a large power system. For the purpose the well established simulator is used.
{"title":"Small signal security quantification of highly loaded power systems","authors":"U. Kerin, E. Lerch, G. Bizjak","doi":"10.1109/PES.2009.5275907","DOIUrl":"https://doi.org/10.1109/PES.2009.5275907","url":null,"abstract":"In this paper a concept of quantifying small signal security of power systems is introduced. The concept includes employment of a security index identifying system oscillation modes of insufficient characteristics. If referred to a security constraint the index quantifies mode security and if applied in sensitivity study it gives mode security variation in respect to changes in the system. The concept is applied in a study case considering model of a large power system. For the purpose the well established simulator is used.","PeriodicalId":258632,"journal":{"name":"2009 IEEE Power & Energy Society General Meeting","volume":"14 6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131071093","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 : 2009-07-26DOI: 10.1109/PES.2009.5275519
H. Kondo, Yuya Suzuki, S. Iwamoto
In recent years, power systems have steadily grown larger and more complicated. Meanwhile, there has been a push toward strong deregulation of the power industry, which has also progressed, causing increases in the PPS (Power Producers and Suppliers) generation ratio and power wheeling via the tie-lines connecting different power companies. These factors all contribute to the increase of uncertainties in the power system. The Sliding mode control theory is one type of robust control theories, which can consider modeling uncertainties. Therefore, in this paper, the Sliding mode control theory is applied to the Load Frequency Control (LFC) in power systems, together with a VSS observer. Its robustness and control performances of the proposed method are examined by numerical simulations and comparisons with the conventional PI controller.
近年来，电力系统逐渐变得越来越大，越来越复杂。与此同时，通过连接各电力公司的配电网，PPS (power Producers and Suppliers)的发电比率和电力转轮也在不断增加，因此，对电力行业的强力管制也在不断推进。这些因素都增加了电力系统的不确定性。滑模控制理论是一类可以考虑建模不确定性的鲁棒控制理论。因此，本文将滑模控制理论与VSS观测器一起应用于电力系统的负载频率控制。通过数值仿真和与传统PI控制器的比较，验证了该方法的鲁棒性和控制性能。
{"title":"A load frequency control design using the sliding mode control theory with a VSS observer","authors":"H. Kondo, Yuya Suzuki, S. Iwamoto","doi":"10.1109/PES.2009.5275519","DOIUrl":"https://doi.org/10.1109/PES.2009.5275519","url":null,"abstract":"In recent years, power systems have steadily grown larger and more complicated. Meanwhile, there has been a push toward strong deregulation of the power industry, which has also progressed, causing increases in the PPS (Power Producers and Suppliers) generation ratio and power wheeling via the tie-lines connecting different power companies. These factors all contribute to the increase of uncertainties in the power system. The Sliding mode control theory is one type of robust control theories, which can consider modeling uncertainties. Therefore, in this paper, the Sliding mode control theory is applied to the Load Frequency Control (LFC) in power systems, together with a VSS observer. Its robustness and control performances of the proposed method are examined by numerical simulations and comparisons with the conventional PI controller.","PeriodicalId":258632,"journal":{"name":"2009 IEEE Power & Energy Society General Meeting","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131164227","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 : 2009-07-26DOI: 10.1109/PES.2009.5275216
H. P. Ladner-Garcia, E. O’Neill-Carrillo
The Puerto Rico Energy Affairs Administration, motivated by the great potential of renewable energy in the Island, commissioned a study to the University of Puerto Rico to identify achievable and realistic renewable energy targets for the Island. The study was intended to summarize the technical requirements of a number of renewable energy technologies in the island and the potential generation capacity achievable in the island. The study will be the basis of a proposal for a renewable energy portfolio in the island. This paper deals with the photovoltaic potential in Puerto Rico. The main finding in the paper is that there is enough proven “rooftop resource” available in the Island to support all the residential energy needs, and significant levels of commercial and industrial energy demand.
{"title":"Determining realistic photovoltaic generation targets in an isolated power system","authors":"H. P. Ladner-Garcia, E. O’Neill-Carrillo","doi":"10.1109/PES.2009.5275216","DOIUrl":"https://doi.org/10.1109/PES.2009.5275216","url":null,"abstract":"The Puerto Rico Energy Affairs Administration, motivated by the great potential of renewable energy in the Island, commissioned a study to the University of Puerto Rico to identify achievable and realistic renewable energy targets for the Island. The study was intended to summarize the technical requirements of a number of renewable energy technologies in the island and the potential generation capacity achievable in the island. The study will be the basis of a proposal for a renewable energy portfolio in the island. This paper deals with the photovoltaic potential in Puerto Rico. The main finding in the paper is that there is enough proven “rooftop resource” available in the Island to support all the residential energy needs, and significant levels of commercial and industrial energy demand.","PeriodicalId":258632,"journal":{"name":"2009 IEEE Power & Energy Society General Meeting","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130688801","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 : 2009-07-26DOI: 10.1109/PES.2009.5275695
F. Alvarado
Electricity markets in many areas of the country continue to operate successfully. In many ways, operating the system according to market bids has proven to be not that different from old style operation under an optimum power dispatch regime; however, the compensation and incentives for market participants and producers are markedly different than previously. Several salient issues have become highlights of at least certain operational regimes under markets.
{"title":"Electricity market equilibrium, efficiency and operation risk: Some observations","authors":"F. Alvarado","doi":"10.1109/PES.2009.5275695","DOIUrl":"https://doi.org/10.1109/PES.2009.5275695","url":null,"abstract":"Electricity markets in many areas of the country continue to operate successfully. In many ways, operating the system according to market bids has proven to be not that different from old style operation under an optimum power dispatch regime; however, the compensation and incentives for market participants and producers are markedly different than previously. Several salient issues have become highlights of at least certain operational regimes under markets.","PeriodicalId":258632,"journal":{"name":"2009 IEEE Power & Energy Society General Meeting","volume":"9 7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132919647","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 : 2009-07-26DOI: 10.1109/PES.2009.5275555
S. Foster, Lie Xu, B. Fox
The paper considers the behaviour of the rotor current of a DFIG during a fault on the network. It is seen that a large disturbance of the stator voltage will cause high transient rotor currents which trigger the crowbar protection for the rotor side converter (RSC). Once the crowbar is applied it cannot be removed until its current reaches zero. During the period the crowbar is applied, the machine behaves as a conventional FSIG, losing control of the active and reactive power. Therefore the time taken for the crowbar current to reach zero is crucial as it determines when the RSC can regain power control and how soon the AC voltage can recover. It is seen that the crowbar current can take a long time to decrease to zero and that this has a significant impact on the voltage recovery after fault. The larger the crowbar resistor and the further the generator is from synchronous speed, the shorter the crowbar current transient is. Power and energy dissipation through the crowbar resistor are also considered, and it is observed that the power varies in accordance with the maximum power transfer theorem. The detailed impact of the timings of crowbar removal and RSC reactivation on system voltage recovery is also investigated. It is seen that reactive power control during fault clearance can assist AC voltage recovery.
{"title":"Behaviour and protection of doubly-fed induction generators during network faults","authors":"S. Foster, Lie Xu, B. Fox","doi":"10.1109/PES.2009.5275555","DOIUrl":"https://doi.org/10.1109/PES.2009.5275555","url":null,"abstract":"The paper considers the behaviour of the rotor current of a DFIG during a fault on the network. It is seen that a large disturbance of the stator voltage will cause high transient rotor currents which trigger the crowbar protection for the rotor side converter (RSC). Once the crowbar is applied it cannot be removed until its current reaches zero. During the period the crowbar is applied, the machine behaves as a conventional FSIG, losing control of the active and reactive power. Therefore the time taken for the crowbar current to reach zero is crucial as it determines when the RSC can regain power control and how soon the AC voltage can recover. It is seen that the crowbar current can take a long time to decrease to zero and that this has a significant impact on the voltage recovery after fault. The larger the crowbar resistor and the further the generator is from synchronous speed, the shorter the crowbar current transient is. Power and energy dissipation through the crowbar resistor are also considered, and it is observed that the power varies in accordance with the maximum power transfer theorem. The detailed impact of the timings of crowbar removal and RSC reactivation on system voltage recovery is also investigated. It is seen that reactive power control during fault clearance can assist AC voltage recovery.","PeriodicalId":258632,"journal":{"name":"2009 IEEE Power & Energy Society General Meeting","volume":"32 2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133040496","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 : 2009-07-26DOI: 10.1109/PES.2009.5275571
N. Iliadis
This article discusses the advances in technology, the market conditions and the biomass solid fuel availability in the South East Europe. The energy mix in South East Europe (SEE) is known to be a highly polluting one with important CO2 and particulates emissions. Following the introduction for several of the countries in the European Union and the signature by most of them of the Kyoto protocol, severe caps have been imposed on the CO2 emissions. Most of the SEE countries have a significant expertise in thermal combustions units based on lignite and coal. Therefore, the use of the solid biomass fuel for electricity generation has started being applied progressively as a means of electricity generation. Pure biomass plants and biomass co-firing plants are actually studied and developed in many of these countries. We refer to as solid biomass all agricultural residues, wood flakes or pellets, olive pomace and any plants that can be used as solid biofuels. Each country among the ones in SEE have different biomass type availabilities which can be transported inside the country or exported to close distances. In this article we will discuss the technologies that have already been applied in South East Europe for different types of biomass. We will stretch the point of biomass solid fuels availability, the regions that can supply important quantities and which neighboring countries can be considered in case of a shortage. The latter availability will be closely linked to the technology that is used each time and the influence of the biomass mix to the technology used. Finally, in order to describe the financial feasibility of these projects we will refer in some financing and feed-in-tariff schemes that are actually applicable.
{"title":"Biomass development and potential in South East Europe","authors":"N. Iliadis","doi":"10.1109/PES.2009.5275571","DOIUrl":"https://doi.org/10.1109/PES.2009.5275571","url":null,"abstract":"This article discusses the advances in technology, the market conditions and the biomass solid fuel availability in the South East Europe. The energy mix in South East Europe (SEE) is known to be a highly polluting one with important CO2 and particulates emissions. Following the introduction for several of the countries in the European Union and the signature by most of them of the Kyoto protocol, severe caps have been imposed on the CO2 emissions. Most of the SEE countries have a significant expertise in thermal combustions units based on lignite and coal. Therefore, the use of the solid biomass fuel for electricity generation has started being applied progressively as a means of electricity generation. Pure biomass plants and biomass co-firing plants are actually studied and developed in many of these countries. We refer to as solid biomass all agricultural residues, wood flakes or pellets, olive pomace and any plants that can be used as solid biofuels. Each country among the ones in SEE have different biomass type availabilities which can be transported inside the country or exported to close distances. In this article we will discuss the technologies that have already been applied in South East Europe for different types of biomass. We will stretch the point of biomass solid fuels availability, the regions that can supply important quantities and which neighboring countries can be considered in case of a shortage. The latter availability will be closely linked to the technology that is used each time and the influence of the biomass mix to the technology used. Finally, in order to describe the financial feasibility of these projects we will refer in some financing and feed-in-tariff schemes that are actually applicable.","PeriodicalId":258632,"journal":{"name":"2009 IEEE Power & Energy Society General Meeting","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133370657","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 : 2009-07-26DOI: 10.1109/PES.2009.5275701
P. Mahat, Zhe Chen, B. Bak‐Jensen
Danish distribution systems are characterized by a significant penetration of small gas turbine generators (GTGs) and fixed speed wind turbine generators (WTGs). Island operation of these distribution systems are becoming a viable option for economical and technical reasons. However, stabilizing frequency in an islanded system is one of the major challenges. This paper presents three different gas turbine governors for possible operation of distribution systems in an islanding mode. Simulation results are presented to show the performance of these governors in grid connected and islanding mode.
{"title":"Gas turbine control for islanding operation of distribution systems","authors":"P. Mahat, Zhe Chen, B. Bak‐Jensen","doi":"10.1109/PES.2009.5275701","DOIUrl":"https://doi.org/10.1109/PES.2009.5275701","url":null,"abstract":"Danish distribution systems are characterized by a significant penetration of small gas turbine generators (GTGs) and fixed speed wind turbine generators (WTGs). Island operation of these distribution systems are becoming a viable option for economical and technical reasons. However, stabilizing frequency in an islanded system is one of the major challenges. This paper presents three different gas turbine governors for possible operation of distribution systems in an islanding mode. Simulation results are presented to show the performance of these governors in grid connected and islanding mode.","PeriodicalId":258632,"journal":{"name":"2009 IEEE Power & Energy Society General Meeting","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132171960","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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