Pub Date : 2022-11-11DOI: 10.1109/APET56294.2022.10073221
Fulu Yan, Mian Hua, Zhi Xun, Dongdong Cao
Aiming at the power quality problem of microgrid, this paper proposes an unbalance compensation method based on pqr theory. By comparing the theoretical degrees of freedom of instantaneous power in abc coordinate system, $alphabeta r$ coordinate system, $ dqtheta$ coordinate system and pqr coordinate system, it is proved that the control flexibility based on pqr theory is better. Considering the influence of non-ideal operating conditions, a pqr coordinate correction method based on a second-order generalized integrator is proposed. The proposed control strategy can improve the unbalance suppression capability, thereby improving the power quality of the system.
{"title":"Unbalance Suppression Strategy Based on PQR Theory for Distribution Network","authors":"Fulu Yan, Mian Hua, Zhi Xun, Dongdong Cao","doi":"10.1109/APET56294.2022.10073221","DOIUrl":"https://doi.org/10.1109/APET56294.2022.10073221","url":null,"abstract":"Aiming at the power quality problem of microgrid, this paper proposes an unbalance compensation method based on pqr theory. By comparing the theoretical degrees of freedom of instantaneous power in abc coordinate system, $alphabeta r$ coordinate system, $ dqtheta$ coordinate system and pqr coordinate system, it is proved that the control flexibility based on pqr theory is better. Considering the influence of non-ideal operating conditions, a pqr coordinate correction method based on a second-order generalized integrator is proposed. The proposed control strategy can improve the unbalance suppression capability, thereby improving the power quality of the system.","PeriodicalId":201727,"journal":{"name":"2022 Asia Power and Electrical Technology Conference (APET)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130354055","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 : 2022-11-11DOI: 10.1109/APET56294.2022.10073442
Gum-Bin Yu, Wang Yao, Liu Qingsong, Xu Pan Teng, Zhu Bo, Jiao Shi
Since the site is adjacent to residential areas, the reactor arrangement needs to consider the influence of reactor noise and thermal field, which is technically difficult. Moreover, the fault caused by overheating of dry hollow shunt reactors occurs from time to time. In order to solve the above problems, according to the service conditions of dry hollow bridge arm reactors, The relationship between the structure form, size, and shape of metal parts of bridge arm reactor and the influence of overheating is studied. According to the model size of typical steel beam structural parts in the valve hall, a simplified simulation model integrating reactor and steel beam structural parts was established, and thermal field simulation research was carried out to obtain the thermal field simulation results. The control scheme to control the temperature difference between the reactor body envelope and the measures to restrain the overheating of metal parts and prevent the overheating of steel beam structure near the reactor in the valve hall are put forward.
{"title":"Research on Preventing Overheating Measures of Dry Hollow Bridge Arm Reactor","authors":"Gum-Bin Yu, Wang Yao, Liu Qingsong, Xu Pan Teng, Zhu Bo, Jiao Shi","doi":"10.1109/APET56294.2022.10073442","DOIUrl":"https://doi.org/10.1109/APET56294.2022.10073442","url":null,"abstract":"Since the site is adjacent to residential areas, the reactor arrangement needs to consider the influence of reactor noise and thermal field, which is technically difficult. Moreover, the fault caused by overheating of dry hollow shunt reactors occurs from time to time. In order to solve the above problems, according to the service conditions of dry hollow bridge arm reactors, The relationship between the structure form, size, and shape of metal parts of bridge arm reactor and the influence of overheating is studied. According to the model size of typical steel beam structural parts in the valve hall, a simplified simulation model integrating reactor and steel beam structural parts was established, and thermal field simulation research was carried out to obtain the thermal field simulation results. The control scheme to control the temperature difference between the reactor body envelope and the measures to restrain the overheating of metal parts and prevent the overheating of steel beam structure near the reactor in the valve hall are put forward.","PeriodicalId":201727,"journal":{"name":"2022 Asia Power and Electrical Technology Conference (APET)","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127152831","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 : 2022-11-11DOI: 10.1109/APET56294.2022.10072464
Guo-Tian Chen, Chunyang Gong, Jun-an Bao, Lihua Zhu, Zhixin Wang
Three-level neutral point clamped (NPC) inverter is widely used in new energy power generation, motor drive and many other occasions. However, the neutral point voltage imbalance of NPC inverter will affect the output of the inverter system, and the control of neutral point voltage has become a research hotspot. In this paper, a compensation voltage injection based neutral point voltage balancing method is proposed, which controls the neutral point current in the switching cycle to realize neutral point voltage self-balance. MATLAB/Simulink simulation model is established to verify the effectiveness of the method, and the simulation results show that the low-frequency fluctuation of the neutral point voltage caused by the modulation wave is eliminated by injecting compensation voltage, the magnitude of high-frequency fluctuation is less than 5% of the low-frequency fluctuation.
{"title":"Compensation Voltage Injection Based Neutral Point Voltage Fluctuation Suppression for NPC Converter","authors":"Guo-Tian Chen, Chunyang Gong, Jun-an Bao, Lihua Zhu, Zhixin Wang","doi":"10.1109/APET56294.2022.10072464","DOIUrl":"https://doi.org/10.1109/APET56294.2022.10072464","url":null,"abstract":"Three-level neutral point clamped (NPC) inverter is widely used in new energy power generation, motor drive and many other occasions. However, the neutral point voltage imbalance of NPC inverter will affect the output of the inverter system, and the control of neutral point voltage has become a research hotspot. In this paper, a compensation voltage injection based neutral point voltage balancing method is proposed, which controls the neutral point current in the switching cycle to realize neutral point voltage self-balance. MATLAB/Simulink simulation model is established to verify the effectiveness of the method, and the simulation results show that the low-frequency fluctuation of the neutral point voltage caused by the modulation wave is eliminated by injecting compensation voltage, the magnitude of high-frequency fluctuation is less than 5% of the low-frequency fluctuation.","PeriodicalId":201727,"journal":{"name":"2022 Asia Power and Electrical Technology Conference (APET)","volume":"86 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115874134","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 : 2022-11-11DOI: 10.1109/APET56294.2022.10073058
Du Hexi, Wu Jinmeng, Meng Fangang
The bi-directional LLC resonant converter cannot realize the ZCS of the primary side when working in the reverse mode, which will generate a large spike voltage at both ends of the switch tube of the reverse primary side. Combined with the working mode of reverse LLC, this paper explains the causes of reverse spike voltage and oscillation in detail through time domain analysis, and improves the control method of reverse LLC resonant converter to make the resonant current participate in the resonance of the excitation inductor, so as to reduce the turn-off current and suppress the spike voltage and oscillation on both sides of the switch tube. Finally, the effectiveness of the synchronous rectification control strategy is verified by the simulation and experiment of 12V/125A1.5KW reverse LLC.
{"title":"Research on the Formation Principle and Suppression Method of Switch Spike Voltage in Reverse LLC Resonant Converter","authors":"Du Hexi, Wu Jinmeng, Meng Fangang","doi":"10.1109/APET56294.2022.10073058","DOIUrl":"https://doi.org/10.1109/APET56294.2022.10073058","url":null,"abstract":"The bi-directional LLC resonant converter cannot realize the ZCS of the primary side when working in the reverse mode, which will generate a large spike voltage at both ends of the switch tube of the reverse primary side. Combined with the working mode of reverse LLC, this paper explains the causes of reverse spike voltage and oscillation in detail through time domain analysis, and improves the control method of reverse LLC resonant converter to make the resonant current participate in the resonance of the excitation inductor, so as to reduce the turn-off current and suppress the spike voltage and oscillation on both sides of the switch tube. Finally, the effectiveness of the synchronous rectification control strategy is verified by the simulation and experiment of 12V/125A1.5KW reverse LLC.","PeriodicalId":201727,"journal":{"name":"2022 Asia Power and Electrical Technology Conference (APET)","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114876392","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 : 2022-11-11DOI: 10.1109/APET56294.2022.10073073
Bing Shen, Yun Su, S. Shi, Jingsong Liu, Haojing Wang, Xiu Yang, Zhongyu Yan
The rapid development of smart grids has put forward new requirements for distribution grids, and the new distribution grids must make breakthroughs in solutions to distributed energy consumption, distribution equipment interconnection and new customer service infrastructure. This paper summarizes the development needs of new distribution networks, compares the current status of medium voltage distribution networks in Japan, Singapore, Paris and China. In the light of the development process of power systems from individual microgrids to microgrid clusters, from electric energy dominance to multi-energy coordination and complementarity, and from traditional rigid switches to flexible interconnection devices, we describe the morphological characteristics and key technologies of new distribution networks such as distributed microgrids, distribution networks with integrated multi-energy production and marketing, and honeycomb distribution networks based on new power electronics. Hopefully, this paper can provide references for the development and construction of future distribution networks.
{"title":"Research on the Morphological Development of New Distribution Networks","authors":"Bing Shen, Yun Su, S. Shi, Jingsong Liu, Haojing Wang, Xiu Yang, Zhongyu Yan","doi":"10.1109/APET56294.2022.10073073","DOIUrl":"https://doi.org/10.1109/APET56294.2022.10073073","url":null,"abstract":"The rapid development of smart grids has put forward new requirements for distribution grids, and the new distribution grids must make breakthroughs in solutions to distributed energy consumption, distribution equipment interconnection and new customer service infrastructure. This paper summarizes the development needs of new distribution networks, compares the current status of medium voltage distribution networks in Japan, Singapore, Paris and China. In the light of the development process of power systems from individual microgrids to microgrid clusters, from electric energy dominance to multi-energy coordination and complementarity, and from traditional rigid switches to flexible interconnection devices, we describe the morphological characteristics and key technologies of new distribution networks such as distributed microgrids, distribution networks with integrated multi-energy production and marketing, and honeycomb distribution networks based on new power electronics. Hopefully, this paper can provide references for the development and construction of future distribution networks.","PeriodicalId":201727,"journal":{"name":"2022 Asia Power and Electrical Technology Conference (APET)","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121838487","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 : 2022-11-11DOI: 10.1109/APET56294.2022.10073434
Ruoyu Zhang, Liangyou Wang, Changping Sun, B. Le, Mian Wang, K. Cui
In order to improve the power output stability and frequency stability when large-scale new energy is integrated into the grid, large-scale new energy base must consider the configuration of energy storage systems with a certain capacity. Facing the demand under the background of new energy development, this paper analyzes the positive impact of energy storage to new energy base. The configuration method of energy storage capacity is proposed, and furthermore, the proposed method is used to calculate the capacity of the energy storage system required to be configured in a typical new energy base, and the power suppression and stability improvement effects brought by the energy storage are evaluated. The case analysis results show that the required energy storage capacity of a new energy base is about 10% of its total wind power and photovoltaic capacity. This configuration ratio can basically achieve the stability of the new energy output fluctuation, and at the same time provides the same frequency regulation capability with conventional generator set of equal capacity.
{"title":"Research on Energy Storage Capacity Configuration Method and Performance Evaluation in New Energy Base","authors":"Ruoyu Zhang, Liangyou Wang, Changping Sun, B. Le, Mian Wang, K. Cui","doi":"10.1109/APET56294.2022.10073434","DOIUrl":"https://doi.org/10.1109/APET56294.2022.10073434","url":null,"abstract":"In order to improve the power output stability and frequency stability when large-scale new energy is integrated into the grid, large-scale new energy base must consider the configuration of energy storage systems with a certain capacity. Facing the demand under the background of new energy development, this paper analyzes the positive impact of energy storage to new energy base. The configuration method of energy storage capacity is proposed, and furthermore, the proposed method is used to calculate the capacity of the energy storage system required to be configured in a typical new energy base, and the power suppression and stability improvement effects brought by the energy storage are evaluated. The case analysis results show that the required energy storage capacity of a new energy base is about 10% of its total wind power and photovoltaic capacity. This configuration ratio can basically achieve the stability of the new energy output fluctuation, and at the same time provides the same frequency regulation capability with conventional generator set of equal capacity.","PeriodicalId":201727,"journal":{"name":"2022 Asia Power and Electrical Technology Conference (APET)","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116905373","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 : 2022-11-11DOI: 10.1109/APET56294.2022.10072875
Juhua Hong, Xiazhe Tu, Shicheng Huang, Linyao Zhang, Xianan Huang, Zhenda Hu, Lin Liu
Various emerging technologies and the development of Internet of Things (IoT) technology make people’s life gradually become intelligent. Electricity IoT is the application of IoT technology in the smart grid, which is increasingly concerned by the global technical staff in the current rapid development of technology. However, with the increase in demand for electricity in various industries, as well as the impact of economic and epidemic factors, the problem of abnormal electricity consumption in industries has become increasingly prominent. Abnormal electricity consumption in the industry can disrupt the normal order of electricity supply and consumption in the grid, leading to huge economic losses. In this regard, many scholars have conducted relevant research and achieved certain results. For the problem of abnormal electricity consumption in the industry, this paper proposes an intelligent early warning model based on biidirectional long short-term memory (BiLSTM) network, which combines multiple factors to determine abnormal electricity consumption for real-time warning, and uses edge cloud structure to make data collection more efficient and comprehensive. The experimental results show that the method proposed in this paper has obvious advantages in the abnormal electricity consumption detection problem, with better real-time and reliability.
{"title":"A BiLSTM-based Industry Abnormal Electricity Consumption Warning Model in the Context of Electricity IoT Edge Cloud","authors":"Juhua Hong, Xiazhe Tu, Shicheng Huang, Linyao Zhang, Xianan Huang, Zhenda Hu, Lin Liu","doi":"10.1109/APET56294.2022.10072875","DOIUrl":"https://doi.org/10.1109/APET56294.2022.10072875","url":null,"abstract":"Various emerging technologies and the development of Internet of Things (IoT) technology make people’s life gradually become intelligent. Electricity IoT is the application of IoT technology in the smart grid, which is increasingly concerned by the global technical staff in the current rapid development of technology. However, with the increase in demand for electricity in various industries, as well as the impact of economic and epidemic factors, the problem of abnormal electricity consumption in industries has become increasingly prominent. Abnormal electricity consumption in the industry can disrupt the normal order of electricity supply and consumption in the grid, leading to huge economic losses. In this regard, many scholars have conducted relevant research and achieved certain results. For the problem of abnormal electricity consumption in the industry, this paper proposes an intelligent early warning model based on biidirectional long short-term memory (BiLSTM) network, which combines multiple factors to determine abnormal electricity consumption for real-time warning, and uses edge cloud structure to make data collection more efficient and comprehensive. The experimental results show that the method proposed in this paper has obvious advantages in the abnormal electricity consumption detection problem, with better real-time and reliability.","PeriodicalId":201727,"journal":{"name":"2022 Asia Power and Electrical Technology Conference (APET)","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115585272","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 : 2022-11-11DOI: 10.1109/apet56294.2022.10072754
{"title":"APET 2022 Cover Page","authors":"","doi":"10.1109/apet56294.2022.10072754","DOIUrl":"https://doi.org/10.1109/apet56294.2022.10072754","url":null,"abstract":"","PeriodicalId":201727,"journal":{"name":"2022 Asia Power and Electrical Technology Conference (APET)","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124810336","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 : 2022-11-11DOI: 10.1109/APET56294.2022.10073206
Chengfei Qi, Ye Xia, Chaoran Bi, Yaoyu Wang, Peisen Yuan
The development of clean energy sources, such as distributed photovoltaic provides an essential means of achieving the ’double carbon’ target. In this paper, we investigate the detection of line loss anomalies based on automated machine learning and the relationship between distributed PV line loss and station area to study the impact of PV on the line loss of the station area. The report is based on data analysis from an empirical case of a constructed PV grid. Based on the example analysis and the anomaly detection model, the significant influencing factors of the impact of low-voltage distributed PV on the station area were obtained.
{"title":"Line Loss Outlier Detection and Correlation Analysis Between Low-voltage Distributed PV Loads: An Empirical Study","authors":"Chengfei Qi, Ye Xia, Chaoran Bi, Yaoyu Wang, Peisen Yuan","doi":"10.1109/APET56294.2022.10073206","DOIUrl":"https://doi.org/10.1109/APET56294.2022.10073206","url":null,"abstract":"The development of clean energy sources, such as distributed photovoltaic provides an essential means of achieving the ’double carbon’ target. In this paper, we investigate the detection of line loss anomalies based on automated machine learning and the relationship between distributed PV line loss and station area to study the impact of PV on the line loss of the station area. The report is based on data analysis from an empirical case of a constructed PV grid. Based on the example analysis and the anomaly detection model, the significant influencing factors of the impact of low-voltage distributed PV on the station area were obtained.","PeriodicalId":201727,"journal":{"name":"2022 Asia Power and Electrical Technology Conference (APET)","volume":"77 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128619312","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}
Reliability centered substation equipment maintenance is developed on the basis of condition-based maintenance or predictive maintenance based on equipment condition monitoring and fault diagnosis. The maintenance scheme and resource allocation are determined by distinguishing different operation states and different influence degrees of equipment to achieve the optimal balance between maintenance cost and power supply reliability. Through a series of decision-making bases, joint maintenance strategies including condition-based maintenance, periodic maintenance, hidden danger detection and post maintenance, as well as the determination of corresponding maintenance cycle, are adopted to improve the power supply reliability and reduce the equipment maintenance cost. This paper summarizes and expounds RCM(Reliability Centered Maintenance) step by step from the selection of reliability indicators, determination of target equipment for implementing RCM, definition of equipment failure mode and its failure diagnosis, maintenance mode decision to system maintenance optimization strategy.
{"title":"Research on Equipment RCM Maintenance Strategy Based on Importance Assessment and Online Fault Monitoring","authors":"Lu Guo, Yongli Liu, Wei Zhang, Pengfei Liu, Tianhua Wang, Qian Wu","doi":"10.1109/APET56294.2022.10073244","DOIUrl":"https://doi.org/10.1109/APET56294.2022.10073244","url":null,"abstract":"Reliability centered substation equipment maintenance is developed on the basis of condition-based maintenance or predictive maintenance based on equipment condition monitoring and fault diagnosis. The maintenance scheme and resource allocation are determined by distinguishing different operation states and different influence degrees of equipment to achieve the optimal balance between maintenance cost and power supply reliability. Through a series of decision-making bases, joint maintenance strategies including condition-based maintenance, periodic maintenance, hidden danger detection and post maintenance, as well as the determination of corresponding maintenance cycle, are adopted to improve the power supply reliability and reduce the equipment maintenance cost. This paper summarizes and expounds RCM(Reliability Centered Maintenance) step by step from the selection of reliability indicators, determination of target equipment for implementing RCM, definition of equipment failure mode and its failure diagnosis, maintenance mode decision to system maintenance optimization strategy.","PeriodicalId":201727,"journal":{"name":"2022 Asia Power and Electrical Technology Conference (APET)","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125986270","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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