Multi-train modeling and simulation plays a vital role in railway electrification during operation and planning phase. Study of peak power demand and energy consumed by each traction substation needs to be deter- mine...Multi-train modeling and simulation plays a vital role in railway electrification during operation and planning phase. Study of peak power demand and energy consumed by each traction substation needs to be deter- mined to verify that electrical energy flowing in its railway power feeding system is appropriate or not. Gauss-Seidel, conventional Newton-Raphson, and current injection methods are well-known and widely accepted as a tool for electrical power network solver in DC railway power supply study. In this paper, a simplified Newton-Raphson method has been proposed. The proposed method employs a set of current-balance equations at each electrical node instead of the conventional power-balance equation used in the conventional Newton-Raphson method. This concept can remarkably reduce execution time and computing complexity for multi-train simulation. To evaluate its use, Sukhumvit line of Bangkok transit system （BTS） of Thai- land with 21.6-km line length and 22 passenger stopping stations is set as a test system. The multi-train simulation integrated with the proposed power network solver is developed to simulate 1-h operation service of selected 5-min headway. From the obtained results, the proposed method is more efficient with approximately 18 % faster than the conventional Newton-Raphson method and just over 6 % faster than the current injection method.展开更多
The present paper discusses ways of adjusting the imbalances of the global economy and its impact on China＇s economy. The analysis in the paper shows that the cut of US fiscal deficits and the appreciation of the cur...The present paper discusses ways of adjusting the imbalances of the global economy and its impact on China＇s economy. The analysis in the paper shows that the cut of US fiscal deficits and the appreciation of the currencies of East Asia, including China＇s RMB, are necessary for a smooth adjustment of the global imbalances. The adjustments will have a positive impact on China＇s economy and will help China realize its external balance. The increase in public spending on the service sector along with the appreciation of RMB will help China realize the internal balance too. The adjustment of the global imbalances will create opportunities and an external pushing force for China in its industrial restructuring and shift in the model of economic growth.展开更多
文摘Multi-train modeling and simulation plays a vital role in railway electrification during operation and planning phase. Study of peak power demand and energy consumed by each traction substation needs to be deter- mined to verify that electrical energy flowing in its railway power feeding system is appropriate or not. Gauss-Seidel, conventional Newton-Raphson, and current injection methods are well-known and widely accepted as a tool for electrical power network solver in DC railway power supply study. In this paper, a simplified Newton-Raphson method has been proposed. The proposed method employs a set of current-balance equations at each electrical node instead of the conventional power-balance equation used in the conventional Newton-Raphson method. This concept can remarkably reduce execution time and computing complexity for multi-train simulation. To evaluate its use, Sukhumvit line of Bangkok transit system （BTS） of Thai- land with 21.6-km line length and 22 passenger stopping stations is set as a test system. The multi-train simulation integrated with the proposed power network solver is developed to simulate 1-h operation service of selected 5-min headway. From the obtained results, the proposed method is more efficient with approximately 18 % faster than the conventional Newton-Raphson method and just over 6 % faster than the current injection method.
文摘The present paper discusses ways of adjusting the imbalances of the global economy and its impact on China＇s economy. The analysis in the paper shows that the cut of US fiscal deficits and the appreciation of the currencies of East Asia, including China＇s RMB, are necessary for a smooth adjustment of the global imbalances. The adjustments will have a positive impact on China＇s economy and will help China realize its external balance. The increase in public spending on the service sector along with the appreciation of RMB will help China realize the internal balance too. The adjustment of the global imbalances will create opportunities and an external pushing force for China in its industrial restructuring and shift in the model of economic growth.
