Electrical characteristics of new three-phase traction power supply system for rail transit

A novel three-phase traction power supply system is proposed to eliminate the adverse effects caused by electric phase separation in catenary and accomplish a unifying manner of traction power supply for rail transit.With the application of two-stage three-phase continuous power supply structure,the electrical characteristics exhibit new features differing from the existing traction system.In this work,the principle for voltage levels determining two-stage network is dissected in accordance with the requirements of traction network and electric locomotive.The equivalent model of three-phase traction system is built for deducing the formula of current distribution and voltage losses.Based on the chain network model of the traction network,a simulation model is established to analyze the electrical characteristics such as traction current distribution,voltage losses,system equivalent impedance,voltage distribution,voltage unbalance and regenerative energy utilization.In a few words,quite a lot traction current of about 99%is undertaken by long-section cable network.The proportion of system voltage losses is small attributed to the two-stage three-phase power supply structure,and the voltage unbal-ance caused by impedance asymmetry of traction network is less than 1‰.In addition,the utilization rate of regenerative energy for locomotive achieves a significant promotion of over 97%.

Properly Understanding Supply–side Structural Reform in the Cultural Sector

The proposal of supply–side structural reform in the cultural sector is based on theoretical inspiration from the economic sector and actual issues in the cultural sector. A proper understanding of the proposal is crucial to the implementation of the reform which should be based on the backgrounds of macroscopic reform and cultural development of the country as well as the need for theoretical innovation. The reform should be carried out with a clear understanding of China's current conditions, a clarification of the reform thinking, the similarities and differences of supply–side structural reforms between the cultural and the economic sectors, as well as an analysis of issues related to the "supply–side" and "structure" in the cultural sector. Concerted efforts from the government through guidance, and market entities through operation should be made to apply appropriately to the reform principle of "unity of doubles effects." Innovations, especially those in technology and institutions, should be promoted as a new momentum to drive cultural development. Concerted efforts from the government and enterprises should underpin optimal supply and a mechanism for competition should be established to ensure effective supply in the cultural sector. In the meantime, the upgrading of demand should be used as a new guidance for effective supply and investment should be oriented to supplement the need for public cultural services. Attention should be paid to a satisfaction–oriented approach to fill the gaps in cultural consumption. For the cultural industry and undertakings, it is now the prime time which brings along great opportunities for development and challenges for reform. From now on the cultural sector should seek its development from transformation and upgrading. Supported by the central government through policy incentives and driven by technological innovations and the capital markets, the cultural industry will maintain stable growth for a relatively long period. In the implementation of supply–side structural reform in a well–organized and all–round way, governments, markets, enterprises, and the industry should each perform their functions and make concerted efforts for innovation to jointly promote the sound development and sustainable growth of the cultural sector.

Economy Equilibrium and Sustainable Development

The structure of technological mappings is studied and it is shown that for an important class of technological mappings there exists a continuous strategy of the behavior of firms as arbitrarily close in terms of profit. The latter is important for building the theory of economic equilibrium, which is an important tool for building the theory of sustainable economic development. Theorems of the existence of economic equilibrium under conditions of uncertainty and under general assumptions about the structure of supply and demand have been proved.

Pathway Planning of Nuclear Power Development Incorporating Assessment of Nuclear Event Risk

The nuclear event risk(NER)is an important and disputed factor that should be reasonably considered when planning the pathway of nuclear power development(NPD)to assess the benefits and risks of developing nuclear power more objectively.This paper aims to explore the impact of nuclear events on NPD pathway planning.The influence of nuclear events is quantified as a monetary risk component,and an optimization model that incorporates the NER in the objective function is proposed.To optimize the pathway of NPD in the lowcarbon transition course of power supply structure evolution,a simulation model is built to deduce alternative NPD pathways and corresponding power supply evolution scenarios under the constraint of an exogenously assigned carbon emission pathway(CEP);moreover,a method is proposed to describe the CEP by superimposing the maximum carbon emission space and each carbon emission reduction(CER)component,and various CER components are clustered considering the emission reduction characteristics and resource endowments of different power generation technologies.A case study is conducted to explore the impact of NER and its risk valuation uncertainty on NPD pathway planning.The method presented in this paper allows the impact of nuclear events on NPD pathway planning to be quantified and improves the level of coordinated optimization of benefits and risks.