Pub Date : 2017-06-01DOI: 10.1109/POWERAFRICA.2017.7991250
W. Banuenumah, F. Sekyere, K. A. Dotche
The paper reported a field survey that sought to examine the technical implications in the adoption of a Global System for Mobile communication GSM-based metering system in the New Juaben Municipality. Both simple random sampling and interview guide methods were used. The issues considered under the study were; understanding of a GSM-based metre reading, mobile phone penetration among consumers, reliability of mobile network services, and security of the central monitoring system over hacking including whether compound housing system of consumers may pose a challenge to the adoption of GSM-based metre system in the Municipality. The respondents disagreed and strongly disagreed that compound housing system may pose a challenge to the adoption of GSM-based metres. Thus, the respondents perceived that the mode of managing electromechanical metres in compound houses would be used to manage GSM-based metres.
{"title":"Field survey of smart metering implementation using a simple random method: A case study of New Juaben Municipality in Ghana","authors":"W. Banuenumah, F. Sekyere, K. A. Dotche","doi":"10.1109/POWERAFRICA.2017.7991250","DOIUrl":"https://doi.org/10.1109/POWERAFRICA.2017.7991250","url":null,"abstract":"The paper reported a field survey that sought to examine the technical implications in the adoption of a Global System for Mobile communication GSM-based metering system in the New Juaben Municipality. Both simple random sampling and interview guide methods were used. The issues considered under the study were; understanding of a GSM-based metre reading, mobile phone penetration among consumers, reliability of mobile network services, and security of the central monitoring system over hacking including whether compound housing system of consumers may pose a challenge to the adoption of GSM-based metre system in the Municipality. The respondents disagreed and strongly disagreed that compound housing system may pose a challenge to the adoption of GSM-based metres. Thus, the respondents perceived that the mode of managing electromechanical metres in compound houses would be used to manage GSM-based metres.","PeriodicalId":6601,"journal":{"name":"2017 IEEE PES PowerAfrica","volume":"68 1","pages":"352-357"},"PeriodicalIF":0.0,"publicationDate":"2017-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90356710","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 : 2017-06-01DOI: 10.1109/POWERAFRICA.2017.7991296
P. Dongbaare, S. O. Osuri, S. Daniel Chowdhury
Smart energy management is a key research area and many strategies that enable control between household appliances and multi-power switching have been examined. However, a limitation of such strategies is that they enable automatic control of household appliances to avoid electricity interruptions and employ renewable energy sources to reduce electricity costs. For proper energy management to be realised, an algorithm needs to be developed that will control and enable the renewable power sources utilisation and automatically limit heavy loads which are in use during peak hours. These include high-consumption stoves, water and space heaters that should adhere to the set limit (automated distributed load limiting mechanism). Therefore, cost-effectiveness of energy and avoidance of electricity interruptions is realised. This paper examines smart energy management systems for residential use that have been implemented and we propose a model that results in the management of energy consumption of household appliances during peak hours based on availability of renewable power sources. Moreover, a smart algorithm that will switch between the various power sources to improve the Distributed Energy Resource (DER) and increase the profit of DER is discussed, as well.
{"title":"A smart energy management system for residential use","authors":"P. Dongbaare, S. O. Osuri, S. Daniel Chowdhury","doi":"10.1109/POWERAFRICA.2017.7991296","DOIUrl":"https://doi.org/10.1109/POWERAFRICA.2017.7991296","url":null,"abstract":"Smart energy management is a key research area and many strategies that enable control between household appliances and multi-power switching have been examined. However, a limitation of such strategies is that they enable automatic control of household appliances to avoid electricity interruptions and employ renewable energy sources to reduce electricity costs. For proper energy management to be realised, an algorithm needs to be developed that will control and enable the renewable power sources utilisation and automatically limit heavy loads which are in use during peak hours. These include high-consumption stoves, water and space heaters that should adhere to the set limit (automated distributed load limiting mechanism). Therefore, cost-effectiveness of energy and avoidance of electricity interruptions is realised. This paper examines smart energy management systems for residential use that have been implemented and we propose a model that results in the management of energy consumption of household appliances during peak hours based on availability of renewable power sources. Moreover, a smart algorithm that will switch between the various power sources to improve the Distributed Energy Resource (DER) and increase the profit of DER is discussed, as well.","PeriodicalId":6601,"journal":{"name":"2017 IEEE PES PowerAfrica","volume":"6 1","pages":"612-616"},"PeriodicalIF":0.0,"publicationDate":"2017-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76878950","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 : 2017-06-01DOI: 10.1109/POWERAFRICA.2017.7991229
Zama Goqo, S. Sewchurran, I. Davidson, O. Ojo
Rising energy costs, growing public concern about environmental impacts of fossil fuel energy generating resources and energy constraints of utilities across the globe have increased the relevance and need for alternative renewable energy resources at the customers point of use. In South Africa, there is a strong interest from electricity suppliers and customers in rooftop photovoltaic systems connection onto the electricity grid, in contrast to utilization of expensive conventional energy storage devices. Specifically, small scale projects are being planned for the near future at municipal level. However, there are known technical issues associated with large-scale connection of rooftop PV systems in low voltage distribution networks and need to be studied in detail and addressed prior commission. This paper presents results of a technical investigation of interconnection of residential rooftop PV systems on an existing low voltage distribution network, implemented in DIgSILENT PowerFactory, representing a housing estate development at eThekwini Electricity.
{"title":"An assessment of voltage rise phenomenon on existing eThekwini Electricity low-voltage distribution network","authors":"Zama Goqo, S. Sewchurran, I. Davidson, O. Ojo","doi":"10.1109/POWERAFRICA.2017.7991229","DOIUrl":"https://doi.org/10.1109/POWERAFRICA.2017.7991229","url":null,"abstract":"Rising energy costs, growing public concern about environmental impacts of fossil fuel energy generating resources and energy constraints of utilities across the globe have increased the relevance and need for alternative renewable energy resources at the customers point of use. In South Africa, there is a strong interest from electricity suppliers and customers in rooftop photovoltaic systems connection onto the electricity grid, in contrast to utilization of expensive conventional energy storage devices. Specifically, small scale projects are being planned for the near future at municipal level. However, there are known technical issues associated with large-scale connection of rooftop PV systems in low voltage distribution networks and need to be studied in detail and addressed prior commission. This paper presents results of a technical investigation of interconnection of residential rooftop PV systems on an existing low voltage distribution network, implemented in DIgSILENT PowerFactory, representing a housing estate development at eThekwini Electricity.","PeriodicalId":6601,"journal":{"name":"2017 IEEE PES PowerAfrica","volume":"36 1","pages":"231-235"},"PeriodicalIF":0.0,"publicationDate":"2017-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79375319","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 : 2017-06-01DOI: 10.1109/POWERAFRICA.2017.7991241
E. Frimpong, P. Okyere, J. Asumadu
A novel scheme is presented for real-time prediction of rotor angle stability status. The scheme is activated following a large disturbance and operates by obtaining a set of two rotor angles for each generator. Each set of two rotor angles sampled is decomposed using the fast Walsh-Hadamard transform resulting in two Walsh coefficients. The absolute value of each coefficient is obtained and the maximum of the two is selected. The selected absolute maximum values, one for each generator, are then summed and fed into a trained support vector machine which predicts the stability status. The scheme was tested using the IEEE 39-bus system. The prediction accuracy of the scheme proved to be 100%.
{"title":"Prediction of transient stability status using Walsh-Hadamard transform and support vector machine","authors":"E. Frimpong, P. Okyere, J. Asumadu","doi":"10.1109/POWERAFRICA.2017.7991241","DOIUrl":"https://doi.org/10.1109/POWERAFRICA.2017.7991241","url":null,"abstract":"A novel scheme is presented for real-time prediction of rotor angle stability status. The scheme is activated following a large disturbance and operates by obtaining a set of two rotor angles for each generator. Each set of two rotor angles sampled is decomposed using the fast Walsh-Hadamard transform resulting in two Walsh coefficients. The absolute value of each coefficient is obtained and the maximum of the two is selected. The selected absolute maximum values, one for each generator, are then summed and fed into a trained support vector machine which predicts the stability status. The scheme was tested using the IEEE 39-bus system. The prediction accuracy of the scheme proved to be 100%.","PeriodicalId":6601,"journal":{"name":"2017 IEEE PES PowerAfrica","volume":"49 1","pages":"301-306"},"PeriodicalIF":0.0,"publicationDate":"2017-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86631637","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 : 2017-06-01DOI: 10.1109/POWERAFRICA.2017.7991268
Elvis Twumasi, E. Frimpong, F. Kemausuor, D. O. Appiah, P. Okyere
This paper presents the results of a survey conducted to determine the extent of students' awareness of energy conservation measures in the use of various electrical appliances as well as their preparedness to support efforts towards reducing energy wastage in institutions. The survey was carried out through the administration of questionnaires. Nine hundred and seventy questionnaires were administered to resident students of the Kwame Nkrumah University of Science and Technology, Kumasi. The results of the survey point to appreciable levels of energy efficiency awareness in the use of various consumer loads. Additionally, a significant number of students were willing to support efforts towards reducing energy wastage.
{"title":"Energy efficiency awareness and preparedness among students","authors":"Elvis Twumasi, E. Frimpong, F. Kemausuor, D. O. Appiah, P. Okyere","doi":"10.1109/POWERAFRICA.2017.7991268","DOIUrl":"https://doi.org/10.1109/POWERAFRICA.2017.7991268","url":null,"abstract":"This paper presents the results of a survey conducted to determine the extent of students' awareness of energy conservation measures in the use of various electrical appliances as well as their preparedness to support efforts towards reducing energy wastage in institutions. The survey was carried out through the administration of questionnaires. Nine hundred and seventy questionnaires were administered to resident students of the Kwame Nkrumah University of Science and Technology, Kumasi. The results of the survey point to appreciable levels of energy efficiency awareness in the use of various consumer loads. Additionally, a significant number of students were willing to support efforts towards reducing energy wastage.","PeriodicalId":6601,"journal":{"name":"2017 IEEE PES PowerAfrica","volume":"21 1","pages":"456-461"},"PeriodicalIF":0.0,"publicationDate":"2017-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86949710","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 : 2017-06-01DOI: 10.1109/POWERAFRICA.2017.7991247
P. McQueen, K. Folly
Controlled grid separation is an emergency preventative measure performed on a system suffering from voltage, frequency or angle instability that is predicted to lead to unplanned system separation. Recent advance in technology has brought about the concept of Wide Area Measurement Protection and Control (WAMPAC) which is based on Phasor Measurement Units (PMUs). PMUs have the ability to measure voltage and current phasors which are referenced to an accurate time signal provided by the Global Positioning System (GPS). This is one of its main advantages over traditional supervisory control and data acquisition (SCADA) systems which use state estimation (SE) to approximate voltage angles and therefore system state. Controlled grid separation using PMUs has received little attention. In this paper, WAMPAC concept based on PMUs is used for controlled separation of a power system so as to prevent cascading blackouts. Simulation results show that WAMPAC concept can be successfully applied to achieve the requirements of controlled separation of the power grid.
{"title":"Phaser measurement units applied to controlled separation of power systems","authors":"P. McQueen, K. Folly","doi":"10.1109/POWERAFRICA.2017.7991247","DOIUrl":"https://doi.org/10.1109/POWERAFRICA.2017.7991247","url":null,"abstract":"Controlled grid separation is an emergency preventative measure performed on a system suffering from voltage, frequency or angle instability that is predicted to lead to unplanned system separation. Recent advance in technology has brought about the concept of Wide Area Measurement Protection and Control (WAMPAC) which is based on Phasor Measurement Units (PMUs). PMUs have the ability to measure voltage and current phasors which are referenced to an accurate time signal provided by the Global Positioning System (GPS). This is one of its main advantages over traditional supervisory control and data acquisition (SCADA) systems which use state estimation (SE) to approximate voltage angles and therefore system state. Controlled grid separation using PMUs has received little attention. In this paper, WAMPAC concept based on PMUs is used for controlled separation of a power system so as to prevent cascading blackouts. Simulation results show that WAMPAC concept can be successfully applied to achieve the requirements of controlled separation of the power grid.","PeriodicalId":6601,"journal":{"name":"2017 IEEE PES PowerAfrica","volume":"1 1","pages":"334-339"},"PeriodicalIF":0.0,"publicationDate":"2017-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82158572","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 : 2017-06-01DOI: 10.1109/POWERAFRICA.2017.7991252
Zongjie Wang, H. Chiang, Zhizhong Guo
The notion that phase voltage magnitudes decrease as loads increase is widely accepted. In this paper, however, two counter examples are presented to show that this notion does not generally hold. The sufficient conditions, under which phase voltage magnitudes of one bus and those of its neighboring buses monotonically decrease with local active and reactive power injections, are given in close form. Intuitive analysis show that the proposed sufficient conditions typically hold in practical networks. The derived monotonic property is illustrated via numerical tests on a 14-bus test system and an IEEE 8,500-node power network. Some potential applications are further discussed.
{"title":"On the phase voltage monotonie property in unbalanced distribution networks","authors":"Zongjie Wang, H. Chiang, Zhizhong Guo","doi":"10.1109/POWERAFRICA.2017.7991252","DOIUrl":"https://doi.org/10.1109/POWERAFRICA.2017.7991252","url":null,"abstract":"The notion that phase voltage magnitudes decrease as loads increase is widely accepted. In this paper, however, two counter examples are presented to show that this notion does not generally hold. The sufficient conditions, under which phase voltage magnitudes of one bus and those of its neighboring buses monotonically decrease with local active and reactive power injections, are given in close form. Intuitive analysis show that the proposed sufficient conditions typically hold in practical networks. The derived monotonic property is illustrated via numerical tests on a 14-bus test system and an IEEE 8,500-node power network. Some potential applications are further discussed.","PeriodicalId":6601,"journal":{"name":"2017 IEEE PES PowerAfrica","volume":"33 1","pages":"366-370"},"PeriodicalIF":0.0,"publicationDate":"2017-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82041413","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 : 2017-06-01DOI: 10.1109/POWERAFRICA.2017.7991258
Bwanga Mbula, S. Daniel Chowdhury
Synchronous Reluctance motors can replace the more commonly used, induction, switched reluctance and permanent magnet motors. They have been shown to outperform similarly dimensioned induction motors in efficiency, torque and power density. They are simple and cheap to construct and require simple control. Such a motor would be ideal for wide spread use in Africa, which currently faces a power deficit, considering that motors account for about 43% of global electric power consumption. The use of synchronous reluctance motors in Electric Vehicles may contribute to the production of more efficient, heavier load and longer range vehicles. This would accelerate adoption of Electric Vehicles and it would help wean the world off fossil fuels. The synchronous reluctance motor has disadvantages of high torque ripple and poor power factor. A radical redesign of the rotor geometry and simultaneous optimisation of the rotor and the stator may significantly improve its performance.
{"title":"Performance improvement of synchronous reluctance motors: A review","authors":"Bwanga Mbula, S. Daniel Chowdhury","doi":"10.1109/POWERAFRICA.2017.7991258","DOIUrl":"https://doi.org/10.1109/POWERAFRICA.2017.7991258","url":null,"abstract":"Synchronous Reluctance motors can replace the more commonly used, induction, switched reluctance and permanent magnet motors. They have been shown to outperform similarly dimensioned induction motors in efficiency, torque and power density. They are simple and cheap to construct and require simple control. Such a motor would be ideal for wide spread use in Africa, which currently faces a power deficit, considering that motors account for about 43% of global electric power consumption. The use of synchronous reluctance motors in Electric Vehicles may contribute to the production of more efficient, heavier load and longer range vehicles. This would accelerate adoption of Electric Vehicles and it would help wean the world off fossil fuels. The synchronous reluctance motor has disadvantages of high torque ripple and poor power factor. A radical redesign of the rotor geometry and simultaneous optimisation of the rotor and the stator may significantly improve its performance.","PeriodicalId":6601,"journal":{"name":"2017 IEEE PES PowerAfrica","volume":"13 1","pages":"402-406"},"PeriodicalIF":0.0,"publicationDate":"2017-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87260810","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 : 2017-06-01DOI: 10.1109/POWERAFRICA.2017.7991289
D. O. Ampofo, Isaac Kofi Otchere, E. Frimpong
The rise in penetration levels of distributed generation (DG) poses some challenges to distribution networks. This paper presents the results of an investigation into the effect of high DG penetration levels on thermal limits of distribution lines, and voltage rise at the point of common coupling. The study system used was the 16-bus UK distribution test system. The results obtained indicate voltage rise as the dominant limiting factor for increasing the penetration level of DGs. Also, the maximum penetration limit of DGs was found to depend on its location and the load profile.
{"title":"An investigative study on penetration limits of distributed generation on distribution networks","authors":"D. O. Ampofo, Isaac Kofi Otchere, E. Frimpong","doi":"10.1109/POWERAFRICA.2017.7991289","DOIUrl":"https://doi.org/10.1109/POWERAFRICA.2017.7991289","url":null,"abstract":"The rise in penetration levels of distributed generation (DG) poses some challenges to distribution networks. This paper presents the results of an investigation into the effect of high DG penetration levels on thermal limits of distribution lines, and voltage rise at the point of common coupling. The study system used was the 16-bus UK distribution test system. The results obtained indicate voltage rise as the dominant limiting factor for increasing the penetration level of DGs. Also, the maximum penetration limit of DGs was found to depend on its location and the load profile.","PeriodicalId":6601,"journal":{"name":"2017 IEEE PES PowerAfrica","volume":"11 1","pages":"573-576"},"PeriodicalIF":0.0,"publicationDate":"2017-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88703381","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 : 2017-06-01DOI: 10.1109/POWERAFRICA.2017.7991286
M. R. Kganyago, B. A. Aderemi, G. Donev, S. Chowdhury
The paper seeks to design, test and implement a fast transfer scheme for an existing Alpha Olefins substation at Sasol Secunda, Mpumalanga Province, in South Africa. The aim of this design is to switch motor bus bars over to an intact back up supply should the main supply fail and to switch them back again when the main supply is restored. The switchover to the back up supply must be performed as quickly and as smoothly as possible to maintain operation and avoid undue stress on the motor shafts. Using all the specification for the switchover procedures required in Alpha Olefins substation, a fast transfer scheme was designed and tested. To achieve this, the normally open tie breaker was utilised. Included will be the panel design for the control circuits of both incomer panels and High-Speed Transfer Devices (HSTD), Intelligent Electronics Devices, (IEDs) with logics.
{"title":"Design and testing of fast transfer scheme for Sasol Secunda","authors":"M. R. Kganyago, B. A. Aderemi, G. Donev, S. Chowdhury","doi":"10.1109/POWERAFRICA.2017.7991286","DOIUrl":"https://doi.org/10.1109/POWERAFRICA.2017.7991286","url":null,"abstract":"The paper seeks to design, test and implement a fast transfer scheme for an existing Alpha Olefins substation at Sasol Secunda, Mpumalanga Province, in South Africa. The aim of this design is to switch motor bus bars over to an intact back up supply should the main supply fail and to switch them back again when the main supply is restored. The switchover to the back up supply must be performed as quickly and as smoothly as possible to maintain operation and avoid undue stress on the motor shafts. Using all the specification for the switchover procedures required in Alpha Olefins substation, a fast transfer scheme was designed and tested. To achieve this, the normally open tie breaker was utilised. Included will be the panel design for the control circuits of both incomer panels and High-Speed Transfer Devices (HSTD), Intelligent Electronics Devices, (IEDs) with logics.","PeriodicalId":6601,"journal":{"name":"2017 IEEE PES PowerAfrica","volume":"9 1","pages":"555-559"},"PeriodicalIF":0.0,"publicationDate":"2017-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89380765","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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