Based on the review of various methods of estimating Gini coefficient, the paper applies a quintile rule to estimate Gini coefficient of rural areas, urban areas and the whole country using the grouped income data of ...Based on the review of various methods of estimating Gini coefficient, the paper applies a quintile rule to estimate Gini coefficient of rural areas, urban areas and the whole country using the grouped income data of urban and rural residents. Besides, the paper uses the curve-fitting method to roughly estimate Gini coefficient from eye-catching Hurun Rich List and the latest poverty line. The result shows that the estimation of Gini coefficient using quintile rule is small for both urban and rural area, while the value of the whole country is obviously larger, which is above the warning line of 0.4. It is indicated that the wealth gap mainly comes from the gap between urban and rural areas. On the other hand, the estimation of Gini coefficient using curve-fitting method is as large as more than 0.7, which implies that the wealth gap is?highlighted from the analysis of the lowest and highest part of the wealth distribution. All in all, China’s current gap between the poor and the rich is serious. The reform of the income distribution needs to speed up to ensure social harmony and stability.展开更多
Operating in island mode when failure occurs in sure to maintain an uninterrupted power supply to significant loads. A two-stage approach that integrates optimal island partition and power dispatch is proposed in this...Operating in island mode when failure occurs in sure to maintain an uninterrupted power supply to significant loads. A two-stage approach that integrates optimal island partition and power dispatch is proposed in this paper, considering photovoltaics(PVs), batteries(BEs) and electric vehicles(EVs) as the power sources. In the first stage, energy indices are defined to describe the energy demand and the maximum energy that these distributed energy resources(DERs) can provide, and islands are partitioned based on an energy constraint. Considering the variability the loads and PVs, the energy constraint is a necessary but not sufficient condition for island operation,so in the second stage, a power dispatch model is proposed the active distribution network(ADN) is an effective mea-as a test for the island partition result. Sequential power flow is also simulated to guarantee a feasible and optimized island status. The situations when the tests are not passed are analyzed and classified, and corresponding modifications for the first stage model are provided. Multiple levels of constraints based on the energy index are established for the island partition model. The proposed approach has been validated through simulation using a modified IEEE 69-bus system which is divided into three districts with different load variability characteristics.展开更多
To facilitate the large-scale integration of distributed wind generation(DWG), the uncertainty of DWG outputs needs to be quantified, and the maximum DWG hosting capacity(DWGHC) of distribution systems must be assesse...To facilitate the large-scale integration of distributed wind generation(DWG), the uncertainty of DWG outputs needs to be quantified, and the maximum DWG hosting capacity(DWGHC) of distribution systems must be assessed. However, the structure of the high-dimensional nonlinear dependencies and the abnormal marginal distributions observed in geographically dispersed DWG outputs lead to the increase of the complexity of the uncertainty analysis. To address this issue,this paper proposes a novel assessment model for DWGHC that considers the spatial correlations between distributed generation(DG) outputs. In our method, an advanced dependence modeling approach called vine copula is applied to capture the high-dimensional correlation between geographically dispersed DWG outputs and generate a sufficient number of correlated scenarios. To avoid an overly conservative hosting capacity in some extreme scenarios, a novel chance-constrained assessment model for DWGHC is developed to determine the optimal sizes and locations of DWG for a given DWG curtailment probability. To handle the computational challenges associated with large-scale scenarios, a bilinear variant of Benders decomposition(BD) is employed to solve the chance-constrained problem.The effectiveness of the proposed method is demonstrated using a typical 38-bus distribution system in eastern China.展开更多
Successful distributed photovoltaic (PV) planning now requires a hosting capacity assessment process that accounts for an appropriate model of PV output and its uncertainty. This paper explores how the PV hosting capa...Successful distributed photovoltaic (PV) planning now requires a hosting capacity assessment process that accounts for an appropriate model of PV output and its uncertainty. This paper explores how the PV hosting capacity of distribution networks can be increased by means of spatial correlation among distributed PV outputs. To achieve this, a novel PV hosting capacity assessment method is proposed to account for arbitrary geographically dispersed distributed PVs. In this method, the empirical relation between the spatial correlation coefficient and distance is fitted by historical data in one place and then applied to model the joint probability distribution of PV outputs at a neighboring location. To derive the PV hosting capacity at candidate locations, a stochastic PV hosting capacity assessment model that aims to maximize the PV hosting capacity under thermal and voltage constraints is proposed. Benders decomposition algorithm is also employed to reduce the computational cost associated with the numerous sampling scenarios. Finally, a rural 59-bus distribution network in Suzhou, China, is used to demonstrate the effectiveness of the proposed PV hosting capacity assessment methodology and the significant benefits obtained by increasing geographical distance.展开更多
A multi-station integration system(MSIS)integrat-ing other multi-type stations provides a new way to realize an intensive development of resources and promote low-carbon en-ergy and its high-efficiency utilization.To ...A multi-station integration system(MSIS)integrat-ing other multi-type stations provides a new way to realize an intensive development of resources and promote low-carbon en-ergy and its high-efficiency utilization.To this end,a novel multi-station integration planning method and coordinated operation strategy model for the MSIS are established in a new business model.In this study,a new business model of the MSIS,with substations as the carrier,integrating distributed photovoltaic,energy storage,electric vehicle charging,data center,and 5G base stations is proposed.From the social environment,natural conditions,and complementary characteristics,a comprehensive index system is established to analyze expansion capability of substations and multi-station combination scheme.Scenario reduction is performed by extracting feature vectors and build-ing a comprehensive evaluation function to select the optimal combination scheme under a specific scenario.Moreover,for the combination scheme in a specific scenario,the optimal ca-pacity configuration and coordinated operation strategy chance-constrained programming model of the MSIS are established under different operating conditions.Finally,simulations are performed on a practical MSIS located in Wuxi,China,and simulation results demonstrate the rationality and effectiveness of the planning method and coordinated operation strategy model for the MSIS.展开更多
The penetration of renewable generation will affect the energy utilization efficiency,economic benefit and reliability of the active distribution network(ADN).This paper proposes a time-sequence production simulation(...The penetration of renewable generation will affect the energy utilization efficiency,economic benefit and reliability of the active distribution network(ADN).This paper proposes a time-sequence production simulation(TSPS)method for re-newable generation capacity and reliability assessments in ADN considering two operational status:the normal status and the fault status.During normal operation,an optimal dispatch model is proposed to promote the renewable consumption and increase the economic benefit.When a failure occurs,the renewable generators are partitioned into islands for resilient power supply and reliability improvement.A novel dynamic island partition model is presented based on mixed integer second-order cone programming(MISOCP).The effectiveness of the proposed TSPS method is demonstrated in a standard network integrated with historical data of load and renewable generations.展开更多
Objective When English-speaking people listen to the Deutsch "high-low" word illusion, they report hearing English words. Whether Chinese-speaking people report Chinese words when listening to the illusion, or wheth...Objective When English-speaking people listen to the Deutsch "high-low" word illusion, they report hearing English words. Whether Chinese-speaking people report Chinese words when listening to the illusion, or whether any reported words might be correlated with personality traits as previous investigations have demonstrated for listening to music in other cultures, is open to question. The present study aimed to address this. Methods A total of 308 right-handed, healthy volunteers (177 women and 131 men) were given the illusion test and asked to answer the Zuckerman-Kuhlman personality questionnaire (ZKPQ). Their depressive tendency was measured by the Plutchik-van Praag depression inventory (PVP). Results There was no gender effect regarding either the PVP score or the number of reported Chinese words from the illusion. Women scored higher on ZKPQ neuroticism-anxiety than men. The number of meaningful Chinese words reported was correlated with the ZKPQ impulsive sensation-seeking, aggression-hostility, and activity scores. Some words reported by participants who scored higher on these three traits were related in meaning to those scales. Conclusion Our preliminary results suggest that when Chinese-speaking people listen to the Deutsch "high-low" word illusion, they might use personality-related, specific cognitive schemata.展开更多
文摘Based on the review of various methods of estimating Gini coefficient, the paper applies a quintile rule to estimate Gini coefficient of rural areas, urban areas and the whole country using the grouped income data of urban and rural residents. Besides, the paper uses the curve-fitting method to roughly estimate Gini coefficient from eye-catching Hurun Rich List and the latest poverty line. The result shows that the estimation of Gini coefficient using quintile rule is small for both urban and rural area, while the value of the whole country is obviously larger, which is above the warning line of 0.4. It is indicated that the wealth gap mainly comes from the gap between urban and rural areas. On the other hand, the estimation of Gini coefficient using curve-fitting method is as large as more than 0.7, which implies that the wealth gap is?highlighted from the analysis of the lowest and highest part of the wealth distribution. All in all, China’s current gap between the poor and the rich is serious. The reform of the income distribution needs to speed up to ensure social harmony and stability.
基金supported in part by the National Science Foundation of China(No.51477029)the National Science and Technology Support Program of China(No.2015BAA01B01)the State Grid Corporation of China(No.SGTYHT/14-JS-188)
文摘Operating in island mode when failure occurs in sure to maintain an uninterrupted power supply to significant loads. A two-stage approach that integrates optimal island partition and power dispatch is proposed in this paper, considering photovoltaics(PVs), batteries(BEs) and electric vehicles(EVs) as the power sources. In the first stage, energy indices are defined to describe the energy demand and the maximum energy that these distributed energy resources(DERs) can provide, and islands are partitioned based on an energy constraint. Considering the variability the loads and PVs, the energy constraint is a necessary but not sufficient condition for island operation,so in the second stage, a power dispatch model is proposed the active distribution network(ADN) is an effective mea-as a test for the island partition result. Sequential power flow is also simulated to guarantee a feasible and optimized island status. The situations when the tests are not passed are analyzed and classified, and corresponding modifications for the first stage model are provided. Multiple levels of constraints based on the energy index are established for the island partition model. The proposed approach has been validated through simulation using a modified IEEE 69-bus system which is divided into three districts with different load variability characteristics.
基金supported by the National Key Research and Development Program of China (No. 2016YFB0900100)High-level Talents Introduction&Research Start-up Fund Program of Nanjing Institute of Technology (No.YKJ202134)。
文摘To facilitate the large-scale integration of distributed wind generation(DWG), the uncertainty of DWG outputs needs to be quantified, and the maximum DWG hosting capacity(DWGHC) of distribution systems must be assessed. However, the structure of the high-dimensional nonlinear dependencies and the abnormal marginal distributions observed in geographically dispersed DWG outputs lead to the increase of the complexity of the uncertainty analysis. To address this issue,this paper proposes a novel assessment model for DWGHC that considers the spatial correlations between distributed generation(DG) outputs. In our method, an advanced dependence modeling approach called vine copula is applied to capture the high-dimensional correlation between geographically dispersed DWG outputs and generate a sufficient number of correlated scenarios. To avoid an overly conservative hosting capacity in some extreme scenarios, a novel chance-constrained assessment model for DWGHC is developed to determine the optimal sizes and locations of DWG for a given DWG curtailment probability. To handle the computational challenges associated with large-scale scenarios, a bilinear variant of Benders decomposition(BD) is employed to solve the chance-constrained problem.The effectiveness of the proposed method is demonstrated using a typical 38-bus distribution system in eastern China.
基金This work was supported in part by the National Key Research and Development Program of China(No.2016YFB0900100)in part by the National Natural Science Foundation of China(No.51807051).
文摘Successful distributed photovoltaic (PV) planning now requires a hosting capacity assessment process that accounts for an appropriate model of PV output and its uncertainty. This paper explores how the PV hosting capacity of distribution networks can be increased by means of spatial correlation among distributed PV outputs. To achieve this, a novel PV hosting capacity assessment method is proposed to account for arbitrary geographically dispersed distributed PVs. In this method, the empirical relation between the spatial correlation coefficient and distance is fitted by historical data in one place and then applied to model the joint probability distribution of PV outputs at a neighboring location. To derive the PV hosting capacity at candidate locations, a stochastic PV hosting capacity assessment model that aims to maximize the PV hosting capacity under thermal and voltage constraints is proposed. Benders decomposition algorithm is also employed to reduce the computational cost associated with the numerous sampling scenarios. Finally, a rural 59-bus distribution network in Suzhou, China, is used to demonstrate the effectiveness of the proposed PV hosting capacity assessment methodology and the significant benefits obtained by increasing geographical distance.
基金the Postgraduate Research&Practice Innovation Program of Jiangsu Province,China(KYCX22_0606)。
文摘A multi-station integration system(MSIS)integrat-ing other multi-type stations provides a new way to realize an intensive development of resources and promote low-carbon en-ergy and its high-efficiency utilization.To this end,a novel multi-station integration planning method and coordinated operation strategy model for the MSIS are established in a new business model.In this study,a new business model of the MSIS,with substations as the carrier,integrating distributed photovoltaic,energy storage,electric vehicle charging,data center,and 5G base stations is proposed.From the social environment,natural conditions,and complementary characteristics,a comprehensive index system is established to analyze expansion capability of substations and multi-station combination scheme.Scenario reduction is performed by extracting feature vectors and build-ing a comprehensive evaluation function to select the optimal combination scheme under a specific scenario.Moreover,for the combination scheme in a specific scenario,the optimal ca-pacity configuration and coordinated operation strategy chance-constrained programming model of the MSIS are established under different operating conditions.Finally,simulations are performed on a practical MSIS located in Wuxi,China,and simulation results demonstrate the rationality and effectiveness of the planning method and coordinated operation strategy model for the MSIS.
基金This work was supported in part by the National Key Research and Development Program of China(Grant No.2016YFB0900100)the National Natural Science Foundation of China(Grant No.51807051)the Natural Science Foundation of Jiangsu Province(Grant No.BK20180507).
文摘The penetration of renewable generation will affect the energy utilization efficiency,economic benefit and reliability of the active distribution network(ADN).This paper proposes a time-sequence production simulation(TSPS)method for re-newable generation capacity and reliability assessments in ADN considering two operational status:the normal status and the fault status.During normal operation,an optimal dispatch model is proposed to promote the renewable consumption and increase the economic benefit.When a failure occurs,the renewable generators are partitioned into islands for resilient power supply and reliability improvement.A novel dynamic island partition model is presented based on mixed integer second-order cone programming(MISOCP).The effectiveness of the proposed TSPS method is demonstrated in a standard network integrated with historical data of load and renewable generations.
基金supported by grants from the National Natural Science Foundation of China (30971042)the Innovative Research Team for Translational Neuropsychiatric Medicine, Zhejiang Province (2011R50049)the Program for Changjiang Scholars and Innovative Research Team in University,Chinese Ministry of Education (IRT1038)
文摘Objective When English-speaking people listen to the Deutsch "high-low" word illusion, they report hearing English words. Whether Chinese-speaking people report Chinese words when listening to the illusion, or whether any reported words might be correlated with personality traits as previous investigations have demonstrated for listening to music in other cultures, is open to question. The present study aimed to address this. Methods A total of 308 right-handed, healthy volunteers (177 women and 131 men) were given the illusion test and asked to answer the Zuckerman-Kuhlman personality questionnaire (ZKPQ). Their depressive tendency was measured by the Plutchik-van Praag depression inventory (PVP). Results There was no gender effect regarding either the PVP score or the number of reported Chinese words from the illusion. Women scored higher on ZKPQ neuroticism-anxiety than men. The number of meaningful Chinese words reported was correlated with the ZKPQ impulsive sensation-seeking, aggression-hostility, and activity scores. Some words reported by participants who scored higher on these three traits were related in meaning to those scales. Conclusion Our preliminary results suggest that when Chinese-speaking people listen to the Deutsch "high-low" word illusion, they might use personality-related, specific cognitive schemata.