Pub Date : 2007-07-01DOI: 10.1109/PCT.2007.4538490
M. Triggianese, F. Liccardo, P. Marino
This paper describes the advantages that can be obtained in ac/dc conversion, when an innovative four-quadrant converter, named synchronous active front-end (SAFE), is employed. The modular system, which increases the availability of the power delivering, can also be designed in order to obtain an improvement of the mission reliability. The reliability of single-AFE topology and the one of a SAFE are here compared. Based on the classical reliability prediction method, this contribution gives a design criteria of the optimum number of the parallel-connected converters and of their switching frequency, in order to match the reliability constrains.
{"title":"Interleaved Active Front-Ends Design Criteria for Reliability improvements","authors":"M. Triggianese, F. Liccardo, P. Marino","doi":"10.1109/PCT.2007.4538490","DOIUrl":"https://doi.org/10.1109/PCT.2007.4538490","url":null,"abstract":"This paper describes the advantages that can be obtained in ac/dc conversion, when an innovative four-quadrant converter, named synchronous active front-end (SAFE), is employed. The modular system, which increases the availability of the power delivering, can also be designed in order to obtain an improvement of the mission reliability. The reliability of single-AFE topology and the one of a SAFE are here compared. Based on the classical reliability prediction method, this contribution gives a design criteria of the optimum number of the parallel-connected converters and of their switching frequency, in order to match the reliability constrains.","PeriodicalId":356805,"journal":{"name":"2007 IEEE Lausanne Power Tech","volume":"121 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134278353","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 : 2007-07-01DOI: 10.1109/PCT.2007.4538661
H. Hatami, Farhad Shahnia, A. Pashaei, S. Hosseini
This paper addresses the issue of modeling and analysis of custom power controllers, power electronic-based equipment aimed at enhancing the reliability and quality of power flows in low voltage distribution networks. A new PWM-based control scheme has been proposed that only requires voltage measurements and no reactive power measurements are required. The operation of the proposed control method is presented for D-STATCOM and DVR. Simulations and analysis are carried out in PSCAD/EMTDC with this control method for two proposed systems. The reliability and robustness of the control scheme in the system response to the voltage disturbances due to system faults or load variations is obviously proved in the simulation results.
{"title":"Investigation on D-STATCOM and DVR Operation for Voltage Control in Distribution Networks with a New Control Strategy","authors":"H. Hatami, Farhad Shahnia, A. Pashaei, S. Hosseini","doi":"10.1109/PCT.2007.4538661","DOIUrl":"https://doi.org/10.1109/PCT.2007.4538661","url":null,"abstract":"This paper addresses the issue of modeling and analysis of custom power controllers, power electronic-based equipment aimed at enhancing the reliability and quality of power flows in low voltage distribution networks. A new PWM-based control scheme has been proposed that only requires voltage measurements and no reactive power measurements are required. The operation of the proposed control method is presented for D-STATCOM and DVR. Simulations and analysis are carried out in PSCAD/EMTDC with this control method for two proposed systems. The reliability and robustness of the control scheme in the system response to the voltage disturbances due to system faults or load variations is obviously proved in the simulation results.","PeriodicalId":356805,"journal":{"name":"2007 IEEE Lausanne Power Tech","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133811799","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 : 2007-07-01DOI: 10.1109/PCT.2007.4538603
T. M. Okraszewski, G. Balzer
This paper provides a synthetic analysis of the actual problems concerning development of the modern electric underground distribution systems. Using randomly chosen 10 kV city network as the example, detailed reliability analysis is performed revealing the problematic issues. Ageing of the assets and unfavorable structural configurations (including unique busbar protection and extended 'inner rings' structures) have significant impact on the system reliability and as such they are demanding serious maturing. The paper considers different network development scenarios and compares the achieved reliability results, which, at the end of the day, may lead to the most beneficial solution.
{"title":"Actual Problems Of The Distribution Cable Networks In Germany - Ageing And Structural Impact On The Reliability","authors":"T. M. Okraszewski, G. Balzer","doi":"10.1109/PCT.2007.4538603","DOIUrl":"https://doi.org/10.1109/PCT.2007.4538603","url":null,"abstract":"This paper provides a synthetic analysis of the actual problems concerning development of the modern electric underground distribution systems. Using randomly chosen 10 kV city network as the example, detailed reliability analysis is performed revealing the problematic issues. Ageing of the assets and unfavorable structural configurations (including unique busbar protection and extended 'inner rings' structures) have significant impact on the system reliability and as such they are demanding serious maturing. The paper considers different network development scenarios and compares the achieved reliability results, which, at the end of the day, may lead to the most beneficial solution.","PeriodicalId":356805,"journal":{"name":"2007 IEEE Lausanne Power Tech","volume":"713 ","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114000187","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 : 2007-07-01DOI: 10.1109/PCT.2007.4538547
R. Langella, A. Testa
A new algorithm for energy measurement at positive sequence of fundamental power frequency under unbalanced non-sinusoidal conditions is presented. Extraction of a generalized positive sequence from the three-phase signals in time domain is performed first. Then, an accurate extraction of fundamental power frequency tones is obtained taking advantage of Hanning windowing together with interpolation of the FFT results. Active and reactive power for energy measurements are finally calculated via traditional formulas. Errors due to fundamental power frequency desynchronization are analyzed for the proposed algorithm and for two alternative traditional algorithms. Finally, numerical applications to simple case studies demonstrate the usefulness of the proposed approach and the importance of considering the positive sequence of the fundamental power frequency for a correct billing of the energy supplied to the costumers.
{"title":"A New Algorithm for Energy Measurement at Positive Sequence of Fundamental Power Frequency, Under Unbalanced Non-Sinusoidal Conditions","authors":"R. Langella, A. Testa","doi":"10.1109/PCT.2007.4538547","DOIUrl":"https://doi.org/10.1109/PCT.2007.4538547","url":null,"abstract":"A new algorithm for energy measurement at positive sequence of fundamental power frequency under unbalanced non-sinusoidal conditions is presented. Extraction of a generalized positive sequence from the three-phase signals in time domain is performed first. Then, an accurate extraction of fundamental power frequency tones is obtained taking advantage of Hanning windowing together with interpolation of the FFT results. Active and reactive power for energy measurements are finally calculated via traditional formulas. Errors due to fundamental power frequency desynchronization are analyzed for the proposed algorithm and for two alternative traditional algorithms. Finally, numerical applications to simple case studies demonstrate the usefulness of the proposed approach and the importance of considering the positive sequence of the fundamental power frequency for a correct billing of the energy supplied to the costumers.","PeriodicalId":356805,"journal":{"name":"2007 IEEE Lausanne Power Tech","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116737736","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 : 2007-07-01DOI: 10.1109/PCT.2007.4538571
T. Rauhala, K. Saarinen, P. Vuorenpaa, P. Jarventausta
In May 2006 two Phasor Measurement Units were installed in Finnish 400 kV transmission grid in order to study subsynchronous damping of 950 MVA generating unit located geographically close to 550 MW HVDC transmission system. Subsynchronous damping was analyzed based on post- disturbance data measured using PMU. In this paper the background of the study and the main results from the measurements over period between May 2006 and August 2006 are presented. The quality of measured subsynchronous oscillations is illustrated and the validity of approach on subsynchronous damping estimation is discussed based on the measurements. Also, amplitude of measured subsynchronous components related to different system disturbances are illustrated and the values determined for total subsynchronous damping based on the post-disturbance measurements are presented. Finally, the possibilities to use PMU output data for real-time monitoring of subsynchronous damping is discussed based on the obtained experiences.
{"title":"Determining Subsynchronous Damping Based on PMU Measurements from Finnish 400 kV Transmission Network","authors":"T. Rauhala, K. Saarinen, P. Vuorenpaa, P. Jarventausta","doi":"10.1109/PCT.2007.4538571","DOIUrl":"https://doi.org/10.1109/PCT.2007.4538571","url":null,"abstract":"In May 2006 two Phasor Measurement Units were installed in Finnish 400 kV transmission grid in order to study subsynchronous damping of 950 MVA generating unit located geographically close to 550 MW HVDC transmission system. Subsynchronous damping was analyzed based on post- disturbance data measured using PMU. In this paper the background of the study and the main results from the measurements over period between May 2006 and August 2006 are presented. The quality of measured subsynchronous oscillations is illustrated and the validity of approach on subsynchronous damping estimation is discussed based on the measurements. Also, amplitude of measured subsynchronous components related to different system disturbances are illustrated and the values determined for total subsynchronous damping based on the post-disturbance measurements are presented. Finally, the possibilities to use PMU output data for real-time monitoring of subsynchronous damping is discussed based on the obtained experiences.","PeriodicalId":356805,"journal":{"name":"2007 IEEE Lausanne Power Tech","volume":"93 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117175654","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 : 2007-07-01DOI: 10.1109/PCT.2007.4538628
J. Kubokawa, Yue Yuan, N. Yorino, Y. Zoka, H. Sasaki, L. Hakim
In nowadays deregulated market, available transfer capability (ATC) is a measure of the network capability for further commercial activity above the already committed uses. This paper deals with the development of an interior point nonlinear programming methodology for evaluating dynamic ATC. By establishing a novel method for integrating transient stability constraints into conventional steady-state ATC problem, we have proposed the dynamic ATC solution methodology using a transient stability constrained OPF (TSCOPF). In actual power system, we have to consider several controller/modeling to evaluate dynamic stability to simulate real system. We have proposed unbalanced three phase model for transmission lines in our TSCOPF. In the proposed method, we can consider any fault sequence on transmission lines and buses. In this paper, we propose an extension of transient stability constrained OPF with consideration of the generator shedding after the fault. The proposed TSCOPF method will be applied to IEEJ EAST10 test system to demonstrate the effectiveness of generator shedding.
{"title":"A Solution of Total Transfer Capability Using Transient Stability Constrained Optimal Power Flow","authors":"J. Kubokawa, Yue Yuan, N. Yorino, Y. Zoka, H. Sasaki, L. Hakim","doi":"10.1109/PCT.2007.4538628","DOIUrl":"https://doi.org/10.1109/PCT.2007.4538628","url":null,"abstract":"In nowadays deregulated market, available transfer capability (ATC) is a measure of the network capability for further commercial activity above the already committed uses. This paper deals with the development of an interior point nonlinear programming methodology for evaluating dynamic ATC. By establishing a novel method for integrating transient stability constraints into conventional steady-state ATC problem, we have proposed the dynamic ATC solution methodology using a transient stability constrained OPF (TSCOPF). In actual power system, we have to consider several controller/modeling to evaluate dynamic stability to simulate real system. We have proposed unbalanced three phase model for transmission lines in our TSCOPF. In the proposed method, we can consider any fault sequence on transmission lines and buses. In this paper, we propose an extension of transient stability constrained OPF with consideration of the generator shedding after the fault. The proposed TSCOPF method will be applied to IEEJ EAST10 test system to demonstrate the effectiveness of generator shedding.","PeriodicalId":356805,"journal":{"name":"2007 IEEE Lausanne Power Tech","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115782265","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 : 2007-07-01DOI: 10.1109/PCT.2007.4538366
P. Pinson, Bernd Nielsen George Klockl, Henrik Aalborg
Short-term (up to 2-3 days ahead) probabilistic forecasts of wind power provide forecast users with a paramount information on the uncertainty of expected wind generation. Whatever the type of these probabilistic forecasts, they are produced on a per horizon basis, and hence do not inform on the development of the forecast uncertainty through forecast series. This issue is addressed here by describing a method that permits to generate statistical scenarios of wind generation that accounts for the interdependence structure of prediction errors, in plus of respecting predictive distributions of wind generation. The approach is evaluated on the test case of a multi-MW wind farm over a period of more than two years. Its interest for a large range of applications is discussed.
{"title":"Generation of Statistical Scenarios of Short-term Wind Power Production","authors":"P. Pinson, Bernd Nielsen George Klockl, Henrik Aalborg","doi":"10.1109/PCT.2007.4538366","DOIUrl":"https://doi.org/10.1109/PCT.2007.4538366","url":null,"abstract":"Short-term (up to 2-3 days ahead) probabilistic forecasts of wind power provide forecast users with a paramount information on the uncertainty of expected wind generation. Whatever the type of these probabilistic forecasts, they are produced on a per horizon basis, and hence do not inform on the development of the forecast uncertainty through forecast series. This issue is addressed here by describing a method that permits to generate statistical scenarios of wind generation that accounts for the interdependence structure of prediction errors, in plus of respecting predictive distributions of wind generation. The approach is evaluated on the test case of a multi-MW wind farm over a period of more than two years. Its interest for a large range of applications is discussed.","PeriodicalId":356805,"journal":{"name":"2007 IEEE Lausanne Power Tech","volume":"114 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123482971","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 : 2007-07-01DOI: 10.1109/PCT.2007.4538446
J. Alvarez, K. Ponnambalam, V. Quintana
In the ideal world, electricity markets are solved under the assumption that all quantities are deterministic. This is the equivalent of assuming that one can perfectly predict future levels of demand and supply. In the real world, the biggest source of uncertainty comes precisely from demand and supply levels. A clear understanding of the economical implications of randomness from supply and demand in electricity markets is still lacking. Random variations of any kind introduce risk. Therefore, one would be interested in somehow minimizing the risk when solving an electricity market. This paper explains the economical implications of minimizing the risk introduced by supply and demand uncertainties. The risk minimization technique used in this work is based on the well known mean-variance Markowitz theory.
{"title":"Electricity Markets under Uncertainty","authors":"J. Alvarez, K. Ponnambalam, V. Quintana","doi":"10.1109/PCT.2007.4538446","DOIUrl":"https://doi.org/10.1109/PCT.2007.4538446","url":null,"abstract":"In the ideal world, electricity markets are solved under the assumption that all quantities are deterministic. This is the equivalent of assuming that one can perfectly predict future levels of demand and supply. In the real world, the biggest source of uncertainty comes precisely from demand and supply levels. A clear understanding of the economical implications of randomness from supply and demand in electricity markets is still lacking. Random variations of any kind introduce risk. Therefore, one would be interested in somehow minimizing the risk when solving an electricity market. This paper explains the economical implications of minimizing the risk introduced by supply and demand uncertainties. The risk minimization technique used in this work is based on the well known mean-variance Markowitz theory.","PeriodicalId":356805,"journal":{"name":"2007 IEEE Lausanne Power Tech","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123028793","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 : 2007-07-01DOI: 10.1109/PCT.2007.4538422
C. Teoh, G. Sheblé
The deregulation policy introduces uncertainties into the power market. The power market uncertainties have increased the significance of two factors in decision analysis: financial risks and managerial flexibility. Real option analysis enables such flexibility to management. There are several major methods under real option analysis: traditional black-Scholes option-pricing method, lattice (binomial and trinomial) methods, Monte Carlo simulation method, and finite element (explicit, implicit, and Crank-Nicolson) method. This paper concentrates on the lattice method. Lattice model is easy to implement, appreciate and understand. However, when the investment duration is large (or the length of model period - step size is small), the lattice model becomes a massive bush of lattice, which is known as the curse of dimensionality. This paper proposes a new efficient methodology of solving the curse of dimensionality for the lattice model. The massive bush of lattice model can be reduced by analyzing the boundary of the lattice where the decision changes. This can be achieved via the implementation of value at risk into the lattice model. Besides reducing the degree of dimensionality, this new methodology also specifies "when" a decision changes. This is a very critical part in strategic budgeting planning. Timing and simplification yet maintaining high accuracy in analysis are essential in the new deregulated power economic uncertainties.
{"title":"Lattice Method of Real Option Analysis - Solving the Curse of Dimensionality and Strategic Planning","authors":"C. Teoh, G. Sheblé","doi":"10.1109/PCT.2007.4538422","DOIUrl":"https://doi.org/10.1109/PCT.2007.4538422","url":null,"abstract":"The deregulation policy introduces uncertainties into the power market. The power market uncertainties have increased the significance of two factors in decision analysis: financial risks and managerial flexibility. Real option analysis enables such flexibility to management. There are several major methods under real option analysis: traditional black-Scholes option-pricing method, lattice (binomial and trinomial) methods, Monte Carlo simulation method, and finite element (explicit, implicit, and Crank-Nicolson) method. This paper concentrates on the lattice method. Lattice model is easy to implement, appreciate and understand. However, when the investment duration is large (or the length of model period - step size is small), the lattice model becomes a massive bush of lattice, which is known as the curse of dimensionality. This paper proposes a new efficient methodology of solving the curse of dimensionality for the lattice model. The massive bush of lattice model can be reduced by analyzing the boundary of the lattice where the decision changes. This can be achieved via the implementation of value at risk into the lattice model. Besides reducing the degree of dimensionality, this new methodology also specifies \"when\" a decision changes. This is a very critical part in strategic budgeting planning. Timing and simplification yet maintaining high accuracy in analysis are essential in the new deregulated power economic uncertainties.","PeriodicalId":356805,"journal":{"name":"2007 IEEE Lausanne Power Tech","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123675544","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 : 2007-07-01DOI: 10.1109/PCT.2007.4538365
E. Spahić, G. Balzer, A. D. Shakib
The largest disadvantage of wind power is its weather dependence, i.e. volatility. With the fast increase of the installed wind power, especially offshore, their impact on the power system operation will increase too. In order to remedy the impact of these drawbacks of the wind power, the use of batteries as power buffer has been investigated. Smoothening of the power fluctuations from large wind farms and use of batteries as primary and secondary control of the wind farm has been analysed. The connection of one "wind farm - battery" unit on a test power system has been modelled. The system with and without the use of battery has been tested. Thereat the power system stability parameters have been observed (rotor angle, voltage and frequency). Obtained results show large improvement in power system stability when using battery as a power backup of large wind farms.
{"title":"The Impact of the \"Wind Farm - Battery\" Unit on the Power System Stability and Control","authors":"E. Spahić, G. Balzer, A. D. Shakib","doi":"10.1109/PCT.2007.4538365","DOIUrl":"https://doi.org/10.1109/PCT.2007.4538365","url":null,"abstract":"The largest disadvantage of wind power is its weather dependence, i.e. volatility. With the fast increase of the installed wind power, especially offshore, their impact on the power system operation will increase too. In order to remedy the impact of these drawbacks of the wind power, the use of batteries as power buffer has been investigated. Smoothening of the power fluctuations from large wind farms and use of batteries as primary and secondary control of the wind farm has been analysed. The connection of one \"wind farm - battery\" unit on a test power system has been modelled. The system with and without the use of battery has been tested. Thereat the power system stability parameters have been observed (rotor angle, voltage and frequency). Obtained results show large improvement in power system stability when using battery as a power backup of large wind farms.","PeriodicalId":356805,"journal":{"name":"2007 IEEE Lausanne Power Tech","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121989370","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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