Study On Electric Buses’ Charge Demand Characteristics And Planning Methods Of Charging Facilities

In the background of our country’s strong support on Electric Vehicles (EVs) industry, EVs industry of China is entering a period of rapid growth; meanwhile the construction of EV charging facilities are being greatly promoted. However, the charging behaviors of a large number of EVs will have many great impacts on power system. On one hand, the impacts of EVs’charging load curves on the original ones are great, which is a challenge to the safe and economic operation of power system. On the other hand, the energy storage characteristics of EVs’and charging facilities are new opportunities to the new energy power generation. In this paper, with the forthcoming large-scale demonstration of EVs, some related studies have been done.On the basis of actual investigations on several domestic large-scale EV charging stations, a reasonable operating mode of electric buses is proposed. A mathematical analysis model for a bus line’s charging demand is set up, and an example simulation is done with it. The result shows that:under the proposed operating mode, the higher SOC is, the lower the peak of the charging load is, the lower the difference between peak and valley is, and the longer battery’s lifetime is. In regard to charging facilities’planning and layout, some elements are considered, including siting, laid density, service radius, and so on. Charging stationes are divided into three:large size, medium size and small size, and the three scale stationes’s equipments and main wiring of them are discussed. The distribution network’s main wiring, capacity, transformer selection are studied in detail. In the angle of loading rate, questiones whether the distribution network needs reformation and capacity expansion are discussed. Finally, to increase energy efficiency of EVs, an "energy storage architecture of charging stations is raised.