Study On Energy Consumption Of Urban Rail Transit And Energy-saving Optimization

China is a country full of energy,but lack of average energy.To coordinate with the strategy of saving energy,China is developing its urban rail transportation system,while in real operation,huge energy consumption still exists.Hence it is important to study the characteristics of urban rail transportation,in order to save energy.On studying energy consumption of urban rail transportation,several integrant parts are concluded,and divided into two parts: train movement energy consumption and station operating energy consumption.Inside parts of train movement energy consumption,train traction takes up a large scale,thus is considered a focal point of study.Characteristics of train traction,including traction force,braking force,resistance,velocity curve etc.are discussed,together with present estimations of train movement energy consumption and some of station operating energy consumption concluded.Influence factors of train movement energy consumption are analyzed,including train's natural characteristics,transportation organization characteristics and rail geographical attributes.Utilizing the theory of Grey Correlative Degree Analysis,several attributes are adopted as variables into the energy consumption calculation model,including daily average operating mileage,technical speed,daily departure time,passenger flow and average temperature.Two energy consumption calculation models are represented by analyzing monthly data of Nanjing Metro Line 3,which are respectively based on multiple linear regression theory and nerve net theory.By analyzing and making comparisons of accuracy and prediction effects the two models,it is concluded that the nerve net model is more adaptable.Considering train movement energy consumption,the train's velocity curve is studied,and a single train energy saving control strategies model considering train movement energy consumption is represented.The maximum principle is conduced to deduce the model,and the results conclude maximum traction,partly traction & partly braking,coasting and maximum braking.The measure of taking reasonable account of coasting time is later studied,and the maximum energy-consumption value of such measure is estimated quantitatively.Under the condition of simplified model,while coasting time reaches a maximum of 16 s,the maximum energy-consumption value comes up to 19.2kWh.Based on real data of Nanjing Metro Line 3,the train's velocity curve is depicted,and the results of train energy saving control strategies model and estimation of energy-consumption is verified.