Research On DC Distribution Voltage Level Sequences To Adapt To The Future Development

With grid power electronic equipment and intermittent power increase, DC power distribution has become a new topic interesting. The construction and application of DC distribution grid, will lead to a series of problems needed to study and solve, including the production and manufacturing of DC electrical equipment, DC cables and other equipment, the structure and characteristics, construction, operation and maintenance of DC distribution network, as well as DC power distribution reliability, safety evaluation. Among them, the voltage level is the most important part of DC power distribution system construction. Since after the construction of grid power, it is very difficult to change the voltage level, especially when a certain scale has formed and then boost, will bring great losses and impact. Therefore, the study of how to select and evaluate DC distribution voltage level scientifically is a research topic of top priority building the future of DC power distribution and whether DC power distribution developed healthy and stable. It will also has an important impact on the future development and decisions of DC grid.For the DC power distribution has been applied in urban rail transport and ship power supply system first. Therefore, Chapter2and Chapter3analyze urban rail transport and ship power supply system DC voltage level sequence and their distribution solutions, elaborate the evaluation method of urban rail transport DC voltage level separately from three aspects including economy, reliability and adaptability. Chapter4studies to determine the public medium-voltage and low-voltage DC power distribution standard voltage level, analyzes the adaptability of the medium-voltage and low-voltage DC power distribution standard voltage level, discusses and shows the reliability evaluation method of converter stations and DC lines, as well as economic evaluation content, evaluation indicators and evaluation methods of the standard voltage level. Chapter5aims the studied and determined DC power distribution standard voltage level, studies the relationship between standard voltage level and DC distribution network structure, analyzes and shows the typical DC distribution network structure of the standard voltage level, for the prospects and construction of DC distribution network, studies and discusses a variety of electrical equipment as well as operation, maintenance problems of DC power distribution system, which improve the construction of DC power distribution system.The main conclusions obtained by this paper including selection and evaluation methods of urban rail transport DC voltage level are available to determine the public medium-voltage and low-voltage DC power distribution voltage level. For there are large differences between ship and land power system environment, the evaluation methods do not apply to the public DC power distribution. Considering compatible with existing cables and to meet the growing social demand for electricity load, saving energy, improving supply capacity, this paper suggests a public DC power distribution medium-voltage standard voltage level of12kV or24kV, considering compatible with DC power distribution voltage at home and abroad, recommends low-voltage standard voltage level of380V. The reliable and economic indicators evaluation of standard voltage level can refer to the evaluation method of urban rail transport DC voltage level index, and the adaption indicators evaluation of standard voltage level can refer to the evaluation method proposed by this paper.