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With the rapid development of electrified railways, its operation reliability is directly related to the safe operation of the power supply system. As a main equipment of the electrified railways traction power supply system, the reliability of traction transformer is directly related to the security of the entire power supply system. For traction transformer, the negative sequence current is the main factor of afety. In the process of transformer switching, the electromagnetic problem is particularly prominent. This paper aims to study the transient response process of the special structure traction transformer. The main research content is to analyze the traction transformer magnetic field distribution with the field-circuit coupling method. Further, the eddy current field of traction transformer core and other structural parts will be researched with the finite element method (FEM) in this paper. Based on this study, this paper also researches the loss distribution of the core and structural parts that is great significance to the electromagnetic design of the transformer and economic operation.

In full knowledge of the energy-saving and emission reduction (ESAER) policies in China, it is analyzed in this paper what the promising new futures in electricity demand in East China in the context of ESAER. To propose the well applicable load forecasting methods for East China power grid, where the ESAER policies have being intensively implemented since 2005, the reality of economic development and industrialization in East China are also discussed. Therefore the well-used long-term forecasting methods are analyzed detailed for their respective applicability under the background of ESAER. Furthermore, in order to take the influence of ESAER policies into account in the forecasting models, the "improved Solow forecasting method" is proposed in this paper. Then these methods are used to forecast the electricity demand from the year 2009 to the year 2015 for East China power grid to check their feasibility. Finally, the forecasting results of electricity demand in East China are analyzed and compared.

With the development of China economy, more and more Special Planned Events(SPE), such as Olympic Games, Expo, Vocal concert, have been held in many metropolitans, which may bring huge pressures to city's normal transportation. In this paper, a traffic flow capability limitation based Logit model at small area for Special Planned Events was set up, and the heuristic algorithm was given in detail. Then, we applied the model and its algorithm to the 2008 Olympic football games in the Tianjin sports centre, and compared with the data obtained by Tianjin Traffic Police Bureau, such traffic flow assignment results were proved reasonable and practicable.