NeTrainSim:a network-level simulator for modeling freight train longitudinal motion and energy consumption

Although train modeling research is vast, most available simulation tools are confined to city-or trip-scale analysis, primarily offering micro-level simulations of network segments. This paper addresses this void by developing the Ne Train Sim simulator for heavy long-haul freight trains on a network of multiple intersecting tracks. The main objective of this simulator is to enable a comprehensive analysis of energy consumption and the associated carbon footprint for the entire train system. Four case studies were conducted to demonstrate the simulator's performance. The first case study validates the model by comparing Ne Train Sim output to empirical trajectory data. The results demonstrate that the simulated trajectory is precise enough to estimate the train energy consumption and carbon dioxide emissions. The second application demonstrates the train-following model considering six trains following each other. The results showcase the model ability to maintain safefollowing distances between successive trains. The next study highlights the simulator's ability to resolve train conflicts for different scenarios. Finally, the suitability of the Ne Train Sim for modeling realistic railroad networks is verified through the modeling of the entire US network and comparing alternative powertrains on the fleet energy consumption.

The relationship between energy consumption and train delay in railway traffic

Based on deterministic NaSch model, we propose a new cellular automation model for simulating train movement. In the proposed model, the reaction time of driver/train equipment is considered. Our study is focused on the additional energy consumption arising by train delay around a traffic bottle （station）. The simulation results demonstrate that the proposed model is suitable for simulating the train movement under high speed condition. Further, we discuss the relationship between the additional energy consumption and some factors which affect the formation of train delay, such as the maximum speed of trains and the station dwell time etc.

Research on the Effects of Train Operation Mode for Vehicle Energy Consumption

The research background is based on great consumption of urban rail transit energy, through summarizing the research of scholars at home and abroad, the comprehensive research including train operation pattern, the train traction characteristics and optimization design of integrated research has carried out in this paper, by using OPENTRACK software simulation to verify the optimization results according to different line features finally. The aim of this paper is to explore ways and methods of traction strategy optimization under the condition of trains timing energy saving. The main research contents of this paper are based on the research status at home and abroad, first of all, the different operating modes of the train running on the line are analysed, including the time saving mode, the energy saving mode and timing energy saving mode, and quantitative analysed the influence of different operation modes on vehicle energy consumption. The influence factors and traction calculation method of energy consumption of train running are studied. Firstly, the factors that affect the energy consumption of the train are analysed, including the basic facilities and transport organization mode. On the basis of this, the train load and running status of the train are analysed, and the model of the train movement and energy consumption are calculated. The OPENTRACK software is used to establish the actual circuit model, and the simulation is verified. The results show that the reasonable operation mode of the train operation mode can greatly reduce the energy consumption.

Train energy simulation with locomotive adhesion model

Railway train energy simulation is an important and popular research topic.Locomotive traction force simulations are a fundamental part of such research.Conventional energy calculation models are not able to consider locomotive wheel-rail adhesions,traction adhesion control,and locomotive dynamics.This paper has developed two models to fill this research gap.The first model uses a 2D locomotive model with 27 degrees of freedom and a simplified wheel-rail contact model.The second model uses a 3D locomotive model with 54 degrees of freedom and a fully detailed wheel-rail contact model.Both models were integrated into a longitudinal train dynamics model with the consideration of locomotive adhesion control.Energy consumption simulations using a conventional model(1D model)and the two new models(2D and 3D models)were conducted and compared.The results show that,due to the consideration of wheel-rail adhesion model and traction control in the 3D model,it reports less energy consumption than the 1D model.The maximum difference in energy consumption rate between the 3D model and the 1D model was 12.5%.Due to the consideration of multiple wheel-rail contact points in the 3D model,it reports higher energy consumption than the 2D model.An 8.6%maximum difference in energy consumption rate between the 3D model and the 1D model was reported during curve negotiation.

Energy Certification of Buildings Training of Experts

According to the Action plan of the Ministry of Environmental Protection, Physical Planning and Construction, the engagement of the implementation of the Directive 2002/91/EC to the Croatian legislation has to be completed in 2009. The final goal of the Directive is the achievement of energy efficiency in buildings, with emphasis on design of building and building elements, heating and cooling systems and use of renewable energy sources. The presentation of energy performances of the building should be visible in energy label that will classify the building in comparison to energy consumption and must be submitted while buying, selling or renting the building. For the realization of energy certification of the building it is required to provide training for wide number of experts. The production of professional basis is ongoing, where besides the building classification and modification or production of correspondingly technical regulations, are determining the conditions and standards for persons who should provide the certification, as well the method of providing.

Hourly energy consumption characteristics of metro rail transit:Train traction versus station operation

The electricity consumption of the urban metro system can be mainly divided into the following two categories:the electricity consumption for train traction(E_(t))and the electricity consumption for station operation(E_(s)).Although understanding the hourly fluctuation characteristics of E_(t) and E_(s) contributes to renewable energy inte-gration and achieving carbon emission reduction of the metro system,the hourly fluctuation characteristics have been poorly reported in the literature.Thus,a typical underground non-transfer metro station of a city’s metro system in the North China Plain is selected in this study,and E_(t) and E_(s) were monitored to portray their hourly fluctuation characteristics.Results reveal that the hourly E_(t) shows a significant intraday“U”shape on weekdays,indicating two symmetric peaks in morning and evening rush hours.While the hourly E_(s) shows an intraday“flat”shape,indicating it is nearly free from the effect of rush hour.Moreover,it is statistically proved that the train frequency is the core influencing factor resulting in the intraday fluctuation of hourly E_(t).In the case study,when the train frequency increases from the mean(20 trains per hour)to maximum(32 trains per hour),the hourly E_(t) will increase by 53.4%.

The Energy Balance of the Electro-Hydraulic Linear Actuation System

The variable gas exchange valve actuation systems have been developed in order to improve the efficiency of the combustion process. The electro-hydraulic valve actuation （EHVA） systems have good power to weight ratio, high maximum force and good controllability. The disadvantages are limited frequency bandwidth and energy recovery. Each component of the EHVA system has certain energy consumption, which is characteristic to the component. In this study the power consumptions of the components are investigated by means of the simulation. The investigated components are a hydraulic pump, a hydraulic accumulator, a control valve, and hydraulic lines connecting the components. The pressure losses caused by the oil flow are most significant in the control valves, 50-60% of the total energy consumption. If the stored kinetic energy of the actuator and moving oil masses could be reused, the energy consumption could be up to 25% better.

UAQ4 Magnetic Levitating Train： Propulsion System for Urban Transportation

This paper discusses the design of the propulsion system of the UAQ4 （University of L＇Aquila, model 4） magnetic levitating train which is used for transportation applications in urban environments. UAQ4 is the only magnetic levitating vehicle with resistance motion, except for aerodynamic drag and with energy consumption near zero at low speed. The feasibility of the system has been successfully verified and tested in the laboratory. Propulsion and braking are provided by a novel direct-current linear stepper motor, with the primary formed by permanent magnets distributed on central beam of the track, and the secondary by coils on board the vehicle, instead of the present alternate current linear motors that have well-known disadvantages. The motor working principles are described, and its performances are analyzed, by a finite element numerical model which allows modifying the most important parameters of the system. The main components of a full scale motor for urban transportation are measured and discussed.

考虑高平峰差异的城市轨道交通节能运行图优化研究

降低能耗是轨道交通绿色低碳、可持续发展的关键。基于“高峰快跑保运力、平峰慢跑降能耗”的思想,本文提出在高平峰时段设置差异化标尺的节能运行图优化方法。首先,根据区间运行时间与列车牵引能耗负相关关系,结合客运服务需求特征,以列车周转牵引能耗最小化为目标构建列车运行标尺优化模型;其次,针对差异化标尺导致的过渡时段列车服务不均匀问题,以列车到站间隔标准差最小化为目标构建列车运行线调整模型;最后,选取福州地铁1号线开展实证分析。结果表明:高平峰差异化标尺节能运行图能够在不改变运力供给、车底运用数量的前提下有效降低全日列车牵引能耗12.56%。所构建方法具有良好的应用价值和可操作性,能够为运营管理人员编制节能运行图提供方法支持。

面向深度神经网络大规模分布式数据并行训练的MC^(2)能耗模型

深度神经网络(deep neural network,DNN)在许多现代人工智能(artificial intelligence,AI)任务中取得了最高的精度.近年来,使用高性能计算平台进行大规模分布式并行训练DNN越来越普遍.能耗模型在设计和优化DNN大规模并行训练和抑制高性能计算平台过量能耗方面起着至关重要的作用.目前,大部分的能耗模型都是从设备的角度出发对单个设备或多个设备构成的集群进行能耗建模,由于缺乏从能耗角度对分布式并行DNN应用进行分解剖析,导致罕有针对分布式DNN应用特征进行建模的能耗模型.针对目前最常用的DNN分布式数据并行训练模式,从DNN模型训练本质特征角度出发,提出了“数据预处理(materials preprocessing)-前向与反向传播(computing)-梯度同步与更新(communicating)”三阶段MC^(2)能耗模型,并通过在国产E级原型机天河三号上使用最多128个MT节点和32个FT节点训练经典的VGG16和ResNet50网络以及最新的Vision Transformer网络验证了模型的有效性和可靠性.实验结果表明,MC^(2)与真实能耗测量结果相差仅为2.84%,相较4种线性比例能耗模型以及AR,SES,ARIMA时间预测模型准确率分别提升了69.12个百分点,69.50个百分点,34.58个百分点,13.47个百分点,5.23个百分点,22.13个百分点,10.53个百分点.通过使用的模型可以在超算平台得到DNN模型的各阶段能耗和总体能耗结果,为评估基于能耗感知的DNN大规模分布式数据并行训练及推理各阶段任务调度、作业放置、模型分割、模型裁剪等优化策略的效能提供了基础.

一种基于自适应PoT量化的无乘法神经网络训练方法

当前的深度神经网络的训练过程中需要包含大量的全精度乘累加(MAC)操作,导致神经网络模型的线性层(包含卷积层和全连接层)的计算过程所需的能耗占整体能耗的绝大部分,达90%以上。本文提出了一种自适应逐层缩放的量化训练方法,可支持在神经网络计算全流程(前向传播和后向传播)将全部线性层中的全精度乘法替换为4位定点数加法计算和1位异或运算。实验结果表明,上述方法在能耗和准确率方面都优于现有方法,可支撑在训练过程中减少达95.8%的线性层能耗,在ImageNet数据集上的卷积神经网络和在WMT En-De任务上的Transformer网络得到小于1%的精度损失。

一种遗传算法的城市轨道列车节能控制策略研究

[目的]城市轨道交通在运营过程中会产生大量能耗,其中列车运行的牵引能耗具有较大优化空间,因此亟需研究一种面向列车牵引节能的控车策略。[方法]首先,建立列车运行的动力学方程,并定义了列车运行过程的约束条件;其次,对列车牵引能耗优化策略进行分解建立目标函数,并基于遗传算法模型对列车运行能耗在不同区间分配和区间最优巡航速度进行求解;然后,通过遗传算法的交叉变异过程,得出节能效果最优的驾驶速度推荐曲线;最后,通过Matlab软件搭建仿真模型并采用真实的线路列车参数和运营数据,模拟列车的站间运行过程。[结果及结论]试验结果表明:基于遗传算法模型的控车策略相较于传统固定工况序列的控车策略,在牵引节能指标上有了显著提升。

基于列车运行多模型的能耗仿真计算

针对目前城市轨道交通系统能耗剧增导致能耗计算量大、计算不够精准的问题,通过考虑电机动态效率,精确计算实际列车侧能耗,并构建基于列车运行单质点和多质点模型的能耗仿真计算模型。首先分析列车牵引传动系统的能量流动过程,建立各部件效率与列车运行状态的关系。然后,结合各部件效率转换,依据两表法推导基于电功率的实际列车能耗计算公式,综合分析影响能耗的因素,进一步提出考虑单质点和多质点列车模型的能耗仿真计算方法。最后,以国内某市域线路的四站三区间为例,验证本文所提能耗模型的准确性。研究结果表明:无论是单质点还是多质点列车运行模型下的运行能耗,与实际运行能耗相比,均能实现5%以内的偏差;在单质点模型的基础上,多质点模型的运行能耗进一步减小了1.66%的偏差。本文所提模型可以为列车节能优化提供理论支撑,助力我国绿色经济发展。

基于GREET模型的氢燃料电池机车全生命周期碳排放与能耗分析

全球性的能源问题和环境问题正日益严重,在实现“双碳”目标的背景下,铁路运输部门需要选择低碳、绿色的燃料。相比较传统柴油动力内燃机车和电力机车,氢燃料电池机车在碳排放与能耗方面的优势值得探究。GREET模型是由美国阿贡国家实验室开发的计算机模拟软件,被广泛地应用于对车辆的能源与环境影响研究中。基于GREET模型,利用WTW (Well-to-Wheels)评价体系对氢燃料电池机车全生命周期的碳排放与能耗效应进行测算。通过与其他车型的对比研究发现:氢燃料电池机车的全生命周期能耗相比内燃机车降低了19.67%,与电力机车相近;氢燃料电池机车的全生命周期碳排放显著低于电力机车和内燃机车。本研究填补了行业中对我国氢燃料电池机车能耗与环境影响方面的研究空白。

基于铁路货物列车节能开行方案的优化研究

为了更好地发挥铁路绿色运营的优势,本文提出面向节能的铁路货物列车开行方案的优化方法。通过对铁路货运线路上的列车运行能耗进行仿真分析,发现不同区间内的运行能耗、不同车站的起停附加能耗差异较大,因此可以通过合理的车流组织来降低能耗。据此,结合铁路实际运输情况,综合考虑铁路运营效益、铁路运输效率、货主时间利益和铁路节能需求,建立铁路货物列车节能开行方案优化模型。选取某铁路线路作为算例验证模型,并对算例结果进行对比分析,结果表明,所构建的优化模型相比其他方案具有更好的优化效果,能够有效降低列车运行能耗并提升运输效率。

城市轨道交通深度节能降耗策略研究

[目的]随着城市轨道交通运营线路的增加及运营时间的增加,电能耗也在逐年增长。为降低电能耗,减少运营成本,需对城市轨道交通节能降耗策略进行深入研究。[方法]分析了城市轨道交通电能耗的构成,归纳了列车牵引能耗、动力设备能耗及照明能耗的影响因素,总结了南宁轨道交通在节能降耗方面所采取的策略及在实践应用中取得的成效,从列车牵引、动力设备、照明等方面提出了城市轨道交通深度节能降耗的策略建议。[结果及结论]南宁轨道交通在2022—2023年通过实施ATO(列车自动驾驶)牵引制动曲线优化、列车空调控制逻辑优化、BAS(环境与设备监控系统)焓值优化、“风、水平衡”调试及照明亮度调节优化等节能降耗策略,使电能耗大幅下降,每条线路每年可节电约16 GWh。建议各地城市轨道交通运营公司结合自身的运营特点,在线路设计、设备及管材选型、施工质量、运营组织、运营管理等方面,制定相应能源消耗及节能管理办法,实现最大限度节能降耗。

基于深度电能消纳数据分析的配电网智能调度算法设计

针对传统数据分析算法在处理配电网电能消纳数据时存在效率较低且难以保证准确率等问题,文中提出了一套基于深度电能消纳数据分析的配电网智能调度算法。该算法使用数据预处理模块将采集到的原始数据进行清洗及归一化处理,进而确保无异常数据输入至CNN网络中。通过搭建完成的CNN网络和训练集数据对相关数据分析模型进行训练,并不断地调整参数,从而得到适用于消纳数据的分析模型。实验结果表明,该算法在满足处理效率的条件下,准确率能够达到90%以上,证明了其可行性。

超级虚拟轨道列车动力选型与牵引仿真分析

针对超级虚拟轨道列车(SRT)特有的动力系统结构和运营方式,以车辆的加速性能和爬坡性能为动力性要求,对车辆的牵引系统参数进行匹配计算,根据已选型的牵引系统参数和车辆结构参数,开展车辆在运营线路上的牵引仿真计算,计算得到的车辆能耗参数,可作为车辆储能系统选型的重要理论依据。

列车控制系统分析及研究

列车控制系统作为轨道交通车辆的控制中枢,影响着列车乃至线路的正常运行关乎着乘客的生命财产安全,为更好地提高系统安全性、控制精度和节约能耗,本文阐述了列车控制系统的关键组成部分、各部分工作原理以及列车控制性能指标,在分析的基础上提出了相应的优化策略,以期为工程应用和相关工作者提供有益的参考。

高速列车运行时车体传热系数K值研究

车体传热系数K值是轨道车辆热工性能的重要指标,是高速列车空调系统能耗的重要影响参数。文章主要采用数值计算的方式,研究了高速列车车体传热系数K值。通过计算高速列车中间车的静止车体传热系数K值及运行条件下的车体传热系数K值,分析了不同运行速度时高速列车中间车车体传热系数K值的变化规律。计算结果表明:列车运行速度越高,车体传热系数K值越大,但增加幅度越来越小。此外,文章还分析了车体传热系数K值的变化对整车空调系统能耗的影响:高速列车以时速380 km运行时,相对于静止状态,由车体传热系数K值增大引起的整车空调系统能耗增加值不大。在设计高速列车时,相对于车体传热系数K值,更应注重列车高速运行时车体气密性。虽然车体传热系数K值增大引起的整车空调系统能耗增加值不大,但通过车体传入车内的热量仍较大,高速列车车体传热系数K值仍需控制在合理的范围内。