Pub Date : 2012-10-01DOI: 10.1109/POWERCON.2012.6401389
Xia-ning Jin, Fuping Wang, Zanji Wang
Precise estimation of synchronized phasors in phasor measurement unit (PMU) is significant for system analysis, control and security. Measurement technique under dynamic conditions is addressed in recent researches. Limitations and criteria for dynamic behaviors are proposed in the new issued IEEE Std. C 37.118-2011 for synchrophasor measurements for power system. In this paper, dynamic characteristics of signals are described as non-stationary signals with amplitude and frequency modulations (AM-FM). A new method for estimating synchronized phasor based on AM-FM demodulation by Energy Operator is presented. In order to avoid the effect of noise, low-pass differentiator is employed. Performance of algorithm is evaluated by simulations and analysis of field data. The result illustrate that the algorithm proposed in this paper improves precision of phasor estimation and reduces response time of PMU, which meets the requirement of the current standard even during dynamic behaviors.
在相量测量单元(PMU)中，同步相量的精确估计对系统分析、控制和安全具有重要意义。动态条件下的测量技术是目前研究的热点。在新发布的IEEE Std. C 37.118-2011中，提出了电力系统同步量测量的限制和动态行为标准。本文将信号的动态特性描述为具有幅频调制(AM-FM)的非平稳信号。提出了一种基于能量算子的调幅调频解调同步相量估计方法。为了避免噪声的影响，采用了低通微分器。通过仿真和现场数据分析，对算法的性能进行了评价。结果表明，本文提出的算法提高了相量估计的精度，缩短了PMU的响应时间，即使在动态行为下也符合现行标准的要求。
{"title":"Dynamic synchronized phasor measurement based on AM-FM demodulation","authors":"Xia-ning Jin, Fuping Wang, Zanji Wang","doi":"10.1109/POWERCON.2012.6401389","DOIUrl":"https://doi.org/10.1109/POWERCON.2012.6401389","url":null,"abstract":"Precise estimation of synchronized phasors in phasor measurement unit (PMU) is significant for system analysis, control and security. Measurement technique under dynamic conditions is addressed in recent researches. Limitations and criteria for dynamic behaviors are proposed in the new issued IEEE Std. C 37.118-2011 for synchrophasor measurements for power system. In this paper, dynamic characteristics of signals are described as non-stationary signals with amplitude and frequency modulations (AM-FM). A new method for estimating synchronized phasor based on AM-FM demodulation by Energy Operator is presented. In order to avoid the effect of noise, low-pass differentiator is employed. Performance of algorithm is evaluated by simulations and analysis of field data. The result illustrate that the algorithm proposed in this paper improves precision of phasor estimation and reduces response time of PMU, which meets the requirement of the current standard even during dynamic behaviors.","PeriodicalId":176214,"journal":{"name":"2012 IEEE International Conference on Power System Technology (POWERCON)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130303803","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 : 2012-10-01DOI: 10.1109/POWERCON.2012.6401455
R. Aihara, A. Yokoyama, F. Nomiyama, H. Kihara
Photovoltaic (PV) generations are expected to have an important role in the near future. However, the power output from the PV is random and intermittent in nature. Therefore, the PV generation poses many challenges to the power system operation. To evaluate impacts of the behavior of PV on the power system operation, we have so far proposed effective use of pumped storage hydro power plant (PSHPP). In the previous research, it takes too much computation time to obtain an optimal scheduling of PHSPP. In this paper, a new optimal scheduling method using efficient economic load dispatch (ELD) calculation and using optimal solutions stored in the database is presented.
{"title":"Optimal operation scheduling of pumped storage hydro power plant using efficient optimization algorithm","authors":"R. Aihara, A. Yokoyama, F. Nomiyama, H. Kihara","doi":"10.1109/POWERCON.2012.6401455","DOIUrl":"https://doi.org/10.1109/POWERCON.2012.6401455","url":null,"abstract":"Photovoltaic (PV) generations are expected to have an important role in the near future. However, the power output from the PV is random and intermittent in nature. Therefore, the PV generation poses many challenges to the power system operation. To evaluate impacts of the behavior of PV on the power system operation, we have so far proposed effective use of pumped storage hydro power plant (PSHPP). In the previous research, it takes too much computation time to obtain an optimal scheduling of PHSPP. In this paper, a new optimal scheduling method using efficient economic load dispatch (ELD) calculation and using optimal solutions stored in the database is presented.","PeriodicalId":176214,"journal":{"name":"2012 IEEE International Conference on Power System Technology (POWERCON)","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115212867","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 : 2012-10-01DOI: 10.1109/POWERCON.2012.6401306
B. Das, N. Watson, Y. Liu
The multi-level current reinjection (MLCR) concept produces high quality line current waveforms in current source converters (CSC) by injecting an reinjection current. Two rein-jected waveforms: Symmetrical waveform and Linear waveform are known. In this paper the influence of varying the zero width period (ZWP) of symmetrical waveform on line current harmonics of self-commutated MLCR CSC is studied. Different ZWPs are used and optimum ZWP is identified. The effect of different ZWP of the linear waveform on the thyristor based MLCR CSC is presented. This paper also investigates the effects of negative firing angle on the THD levels of the line currents drawn by both CSCs using PSCAD/EMTDC.
{"title":"Influence of zero width period on the AC-side line current harmonics of 5-level MLCR CSC","authors":"B. Das, N. Watson, Y. Liu","doi":"10.1109/POWERCON.2012.6401306","DOIUrl":"https://doi.org/10.1109/POWERCON.2012.6401306","url":null,"abstract":"The multi-level current reinjection (MLCR) concept produces high quality line current waveforms in current source converters (CSC) by injecting an reinjection current. Two rein-jected waveforms: Symmetrical waveform and Linear waveform are known. In this paper the influence of varying the zero width period (ZWP) of symmetrical waveform on line current harmonics of self-commutated MLCR CSC is studied. Different ZWPs are used and optimum ZWP is identified. The effect of different ZWP of the linear waveform on the thyristor based MLCR CSC is presented. This paper also investigates the effects of negative firing angle on the THD levels of the line currents drawn by both CSCs using PSCAD/EMTDC.","PeriodicalId":176214,"journal":{"name":"2012 IEEE International Conference on Power System Technology (POWERCON)","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114313030","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 : 2012-10-01DOI: 10.1109/POWERCON.2012.6401284
M. Cupelli, C. Doig Cardet, A. Monti
This paper discusses the performance of two different line voltage stability indices previously studied in literature the Line stability Index (Lmn) and Voltage Collapse Point Indicators (VCPI). The objective is to identify which index is most suitable for being used in control applications. The results presented here will provide a first indication. The indices were tested in the IEEE 39-bus system. The RTDS simulator was used to create data sets and the indices where computed using the control block components for real time operation. This method was chosen to have the values of the indices available for future development of control algorithms based on stability indices.
{"title":"Voltage stability indices comparison on the IEEE-39 bus system using RTDS","authors":"M. Cupelli, C. Doig Cardet, A. Monti","doi":"10.1109/POWERCON.2012.6401284","DOIUrl":"https://doi.org/10.1109/POWERCON.2012.6401284","url":null,"abstract":"This paper discusses the performance of two different line voltage stability indices previously studied in literature the Line stability Index (Lmn) and Voltage Collapse Point Indicators (VCPI). The objective is to identify which index is most suitable for being used in control applications. The results presented here will provide a first indication. The indices were tested in the IEEE 39-bus system. The RTDS simulator was used to create data sets and the indices where computed using the control block components for real time operation. This method was chosen to have the values of the indices available for future development of control algorithms based on stability indices.","PeriodicalId":176214,"journal":{"name":"2012 IEEE International Conference on Power System Technology (POWERCON)","volume":"65 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114211483","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 : 2012-10-01DOI: 10.1109/POWERCON.2012.6401364
Bin Wang, G. He, S. Mei
Although a great amount of achievements on the power system state estimation have been obtained in the past decades, few results about the credibility assessment of state estimation are presented. This paper proposes a Cumulant-based approach to assess the credibility of the estimated results in the case that the true values are unknown. The credibility indicators based on confidence intervals are provided to quantify the accuracy of the estimated results and the validity of the state estimator. The Cumulant method is applied to determine the statistical characteristic of estimated results, so that the confidence intervals can be figured out flexibly. The assessment results are very helpful for avoiding low-accuracy estimation. Results using the proposed method are compared against Monte-Carlo Simulations to demonstrate the accuracy of the results. Then, the validity of the credibility indicators is illustrated. Tests are carried on the IEEE 14-bus system and the IEEE 57-bus system respectively.
{"title":"A Cumulant-based method for credibility assessment of power system state estimation","authors":"Bin Wang, G. He, S. Mei","doi":"10.1109/POWERCON.2012.6401364","DOIUrl":"https://doi.org/10.1109/POWERCON.2012.6401364","url":null,"abstract":"Although a great amount of achievements on the power system state estimation have been obtained in the past decades, few results about the credibility assessment of state estimation are presented. This paper proposes a Cumulant-based approach to assess the credibility of the estimated results in the case that the true values are unknown. The credibility indicators based on confidence intervals are provided to quantify the accuracy of the estimated results and the validity of the state estimator. The Cumulant method is applied to determine the statistical characteristic of estimated results, so that the confidence intervals can be figured out flexibly. The assessment results are very helpful for avoiding low-accuracy estimation. Results using the proposed method are compared against Monte-Carlo Simulations to demonstrate the accuracy of the results. Then, the validity of the credibility indicators is illustrated. Tests are carried on the IEEE 14-bus system and the IEEE 57-bus system respectively.","PeriodicalId":176214,"journal":{"name":"2012 IEEE International Conference on Power System Technology (POWERCON)","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114538682","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 : 2012-10-01DOI: 10.1109/POWERCON.2012.6401467
C. Cabrera, S. Chiu, N. Nair
Timely bus protection is extremely critical due to the widespread instability of the power system that can occur due to a bus fault. In addition to existing conventional ways of 11 kV bus protection a newer possibility of arc-flash protection using IEC 61850 generic object oriented substation event (GOOSE) messaging is now possible. Arc-flash protection has both high selectivity and security and relatively it costs less with other comparable schemes. This paper describes the design and implementation of Arc-Flash Protection using IEC 61850 based GOOSE messaging at a real substation in New Zealand. Further development and application of this form of 11kV bus protection happening in Powerco will also be discussed.
{"title":"Implementation of Arc-Flash Protection using IEC 61850 Goose messaging","authors":"C. Cabrera, S. Chiu, N. Nair","doi":"10.1109/POWERCON.2012.6401467","DOIUrl":"https://doi.org/10.1109/POWERCON.2012.6401467","url":null,"abstract":"Timely bus protection is extremely critical due to the widespread instability of the power system that can occur due to a bus fault. In addition to existing conventional ways of 11 kV bus protection a newer possibility of arc-flash protection using IEC 61850 generic object oriented substation event (GOOSE) messaging is now possible. Arc-flash protection has both high selectivity and security and relatively it costs less with other comparable schemes. This paper describes the design and implementation of Arc-Flash Protection using IEC 61850 based GOOSE messaging at a real substation in New Zealand. Further development and application of this form of 11kV bus protection happening in Powerco will also be discussed.","PeriodicalId":176214,"journal":{"name":"2012 IEEE International Conference on Power System Technology (POWERCON)","volume":"82 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114621746","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 : 2012-10-01DOI: 10.1109/POWERCON.2012.6401281
P. Binh, N. T. Hung, P. Q. Dung, Lee-Hong Hee
The electrical loads is the non-stationary time series. With the non-stationary time series, the wavelet technique is more effective technique for approximation. In recent year the fuzzy-wavelet is more attractive for forecasting problem. This paper presented the load curve and electricity consumption forecasting based on MODWT and fuzzy logic. For each individual wavelet sub-series, the fuzzy-rules will be determined in order to carry out the forecasting. After that, the individual wavelet sub-series forecasts are recombined to give the final result.
{"title":"Load forecasting based on wavelet transform and fuzzy logic","authors":"P. Binh, N. T. Hung, P. Q. Dung, Lee-Hong Hee","doi":"10.1109/POWERCON.2012.6401281","DOIUrl":"https://doi.org/10.1109/POWERCON.2012.6401281","url":null,"abstract":"The electrical loads is the non-stationary time series. With the non-stationary time series, the wavelet technique is more effective technique for approximation. In recent year the fuzzy-wavelet is more attractive for forecasting problem. This paper presented the load curve and electricity consumption forecasting based on MODWT and fuzzy logic. For each individual wavelet sub-series, the fuzzy-rules will be determined in order to carry out the forecasting. After that, the individual wavelet sub-series forecasts are recombined to give the final result.","PeriodicalId":176214,"journal":{"name":"2012 IEEE International Conference on Power System Technology (POWERCON)","volume":"136 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123589606","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 : 2012-10-01DOI: 10.1109/POWERCON.2012.6401300
B. Das, N. Watson, Y. Liu
Multi-level Current Reinjection (MLCR) concept adds self commutation capability to thyristors, and produces a high quality line current waveforms and provides reactive power compensation in current source converters (CSC). Multi-level conversion is applied to generate the required optimum linear multilevel injection current which, when reinjected to the ac side, reduces the line current total harmonic distortion (THD) and forces the thyristor current to be zero. In this paper a comparative study is carried out for a 3-level, 5-level, and 7-level thyristor based MLCR CSC in terms of line current THD obtained, reinjection transformer requirements, reinjection switch ratings, and reinjection control circuitry complexities. Extensive PSCAD/EMTDC simulations are presented for comparing the different m-level reinjection schemes.
{"title":"m-level thyristor based MLCR CSC: A comparative study","authors":"B. Das, N. Watson, Y. Liu","doi":"10.1109/POWERCON.2012.6401300","DOIUrl":"https://doi.org/10.1109/POWERCON.2012.6401300","url":null,"abstract":"Multi-level Current Reinjection (MLCR) concept adds self commutation capability to thyristors, and produces a high quality line current waveforms and provides reactive power compensation in current source converters (CSC). Multi-level conversion is applied to generate the required optimum linear multilevel injection current which, when reinjected to the ac side, reduces the line current total harmonic distortion (THD) and forces the thyristor current to be zero. In this paper a comparative study is carried out for a 3-level, 5-level, and 7-level thyristor based MLCR CSC in terms of line current THD obtained, reinjection transformer requirements, reinjection switch ratings, and reinjection control circuitry complexities. Extensive PSCAD/EMTDC simulations are presented for comparing the different m-level reinjection schemes.","PeriodicalId":176214,"journal":{"name":"2012 IEEE International Conference on Power System Technology (POWERCON)","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129606928","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 : 2012-10-01DOI: 10.1109/POWERCON.2012.6401386
B. Parekh, S. Sharma, P. Sharma
Information technology played an important role in information and knowledge dissemination in the last decade in the almost all the domains through the development of internet, wireless, satellites and mobile based intelligent knowledge based information system. These systems need timely expert advice to make them more productive and competitive. By implementing them as knowledge servers, it becomes economically feasible, profitable, and beneficial to users to share knowledge. The Indian tariff structure for power generation utilities has also undergone major revision under the ABT regime. As a result, the operation philosophy employed by power generation utilities also has undergone change under the ABT. The proposed solution aims to help the end user (as a large power generation utility) to manage their resources in the most optimal and economic fashion under the new regime. Scheduling implies drawing up a generation program to cater to forecast power demand at a minimum cost subject to transmission system constraints, capability of generating units & other factors (e.g. voltage profile, system security & system sustainability under grid disturbance). Architecture for Optimization of Generator Scheduling under ABT Regime Using Intelligent Agents is proposed involving Tariff modeling engine, Generation scheduling engine, Generation target achievement engine, etc.
{"title":"Architecture for optimization of generator scheduling under ABT regime using intelligent agents","authors":"B. Parekh, S. Sharma, P. Sharma","doi":"10.1109/POWERCON.2012.6401386","DOIUrl":"https://doi.org/10.1109/POWERCON.2012.6401386","url":null,"abstract":"Information technology played an important role in information and knowledge dissemination in the last decade in the almost all the domains through the development of internet, wireless, satellites and mobile based intelligent knowledge based information system. These systems need timely expert advice to make them more productive and competitive. By implementing them as knowledge servers, it becomes economically feasible, profitable, and beneficial to users to share knowledge. The Indian tariff structure for power generation utilities has also undergone major revision under the ABT regime. As a result, the operation philosophy employed by power generation utilities also has undergone change under the ABT. The proposed solution aims to help the end user (as a large power generation utility) to manage their resources in the most optimal and economic fashion under the new regime. Scheduling implies drawing up a generation program to cater to forecast power demand at a minimum cost subject to transmission system constraints, capability of generating units & other factors (e.g. voltage profile, system security & system sustainability under grid disturbance). Architecture for Optimization of Generator Scheduling under ABT Regime Using Intelligent Agents is proposed involving Tariff modeling engine, Generation scheduling engine, Generation target achievement engine, etc.","PeriodicalId":176214,"journal":{"name":"2012 IEEE International Conference on Power System Technology (POWERCON)","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115982638","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 : 2012-10-01DOI: 10.1109/POWERCON.2012.6401383
T. D. Nguyen, Goro Fujita
In this research, the novel hysteresis current controller in dq reference frame is proposed to replace the traditional Proportional-Integral (PI) regulator in the vector control scheme of Doubly Fed Induction Generator (DFIG). More dominant than conventional hysteresis current controller, this algorithm can modulate the voltage space vector directly in the dq rotation frame. Therefore, it is simple to employ the new method in the vector control scheme of DFIG. In addition, it can be used in demagnetizing current control scheme to ride through the grid voltage disturbances. The simulation results demonstrated the very fast dynamic responses of power control and the ride through capability of this method under voltage dips.
{"title":"Nonlinear control of DFIG under symmetrical voltage dips with demagnetizing current solution","authors":"T. D. Nguyen, Goro Fujita","doi":"10.1109/POWERCON.2012.6401383","DOIUrl":"https://doi.org/10.1109/POWERCON.2012.6401383","url":null,"abstract":"In this research, the novel hysteresis current controller in dq reference frame is proposed to replace the traditional Proportional-Integral (PI) regulator in the vector control scheme of Doubly Fed Induction Generator (DFIG). More dominant than conventional hysteresis current controller, this algorithm can modulate the voltage space vector directly in the dq rotation frame. Therefore, it is simple to employ the new method in the vector control scheme of DFIG. In addition, it can be used in demagnetizing current control scheme to ride through the grid voltage disturbances. The simulation results demonstrated the very fast dynamic responses of power control and the ride through capability of this method under voltage dips.","PeriodicalId":176214,"journal":{"name":"2012 IEEE International Conference on Power System Technology (POWERCON)","volume":"207 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124424521","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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