Alternating traction current dynamics in track lines of double-track hauls

The operational stability of track circuits and continuous cab signaling in electrified railway sections is disturbed most often by traction current noises in the track line. They are generated when asymmetrical traction current is produced at the points where track circuit equipment is connected to the tracks or under sending cab coils of continuous cab signaling. From the standpoint of traction current flows, a single-track haul track line can be considered a solitary double-wire circuit with two reciprocally induced singlewire electric circuits. As a result, traction current asymmetry becomes easier to calculate. In the case of double-track hauls, this problem is much more difficult to solve, because the traction network in these hauls additionally includes electrified trackways of adjacent tracks, second contact wire, and longitudinal power supply lines laid on catenary supports. These lines are reciprocally inductive with the considered trackways. The considered hauls are characterized by different distances from each trackway to additional electric lines, for which reason the reciprocal inductances inversely related to these distances are different as well. According to the analysis of the proposed procedure of calculating the traction current asymmetry in the track line, this asymmetry depends not only on electric resistances and specific reciprocal inductances of interlinked singlewire electric power lines, but also on the ratio of currents in these lines. It has been established that the absolute value of traction current asymmetry at a particular point of the track lines is indicated more adequately by the level of impact of traction current asymmetry on the operational stability of track circuits than by the traction current asymmetry factor. The time course of the traction current asymmetry in the track line depends on variations in the ambient temperature, traction current in the rails, and electric resistances in the junctions of parts of track bonds, choke jumpers, and ground circuits of catenary line supports. Additional changes in the traction current asymmetry under sending cab coils occur during train traffic and depend on the inbound resistances of track line sections ahead, as well as on any uneven longitudinal track magnetization.     

一种应用于动车组牵引变流器控制的变压器直流偏磁抑制方法

动车组(EMU)牵引供电系统采用25 kV单相牵引变压器从接触网取电,EMU运行过程中的弓网离线、功率器件的非线性特性、硬件电路和控制系统的不对称性等,均会引起直流分量通过电气回路注入车载牵引变压器,引起变压器的直流偏磁。通过将比例-积分-谐振(PIR)控制应用于电流内环控制器,同时实现正弦信号的稳定跟踪和直流分量的抑制。仿真和硬件在环的半实物仿真结果验证了该控制策略的有效性。     

Methods of determining the interference current in rails of double subway track circuits

This article is devoted to solving the problem of determination of rates of electric rolling stock conductive interference on the mechanisms of subway track circuits using the example of SUE Petersburg Subway System. This allows us to investigate the electromagnetic compatibility of rolling stock and train traffic control devices, first of all, track circuits. These problems are solved using the electromagnetic compatibility theory. Some features of the interference that appear during track circuit operation are described in this paper, including separation of interference to danger and interrupting. The investigation has shown that the requirements for the interference current that is generated by the rolling stock should be standardized for investigating the electromagnetic compatibility of electric rolling stock with a frequency motor and track circuit equipment. The main information from the standards based on the research is given. The rates of danger and interrupting interference on the rolling stock currents are given. Also the rates of interference currents in the audio frequency track circuits and the track circuits with the frequency of 50 Hz, and the rates of interference currents in the rails for specified asymmetry coefficient are given.     

地铁直流电缆放电在线检测中干扰信号的研究

为解决地铁直流电缆电气接线的特殊性而导致其放电检测中存在的大量干扰信号,实验研究了整流装置产生的整流脉冲、机车启动制动产生的电流脉冲、随机性脉冲信号及其它电子设备产生的窄带信号等干扰信号的特征。研究表明,并联的被测电缆上均存在很好的整流脉冲干扰周期性和规律性;窄带干扰和机车反馈电流脉冲干扰幅值大但其频谱较低(<2MHz);随机脉冲干扰信号虽具有不确定性,但其重复率与电缆放电的重复率存在数量级差别。根据干扰信号特征提出了可行的抗干扰措施,为检测地铁直流电缆放电奠定了基础。     

电铁负荷特性对微机保护启动元件的影响研究

为研究电铁负荷对微机保护启动元件算法的影响,根据某区域电网实际参数,利用PSCAD建立了典型电气化铁路牵引系统模型,及微机保护中相电流突变量启动、相间电流突变量启动及半周电流积分启动三种常见启动元件的数学模型。在此基础上,结合电铁负荷的特性,从理论上分析了电铁负荷对三种算法的影响,并进行了数字仿真验证,得出电铁负荷对各启动算法影响的相关结论,为在电铁负荷较重地区装设的微机保护装置启动元件算法选择提供了理论依据。     

城市轨道交通杂散电流治理的综述与评估

杂散电流会造成电气化交通系统附近金属结构腐蚀,该现象在普遍采用直流牵引供电的城市轨道交通中尤为突出.该文分别对城市轨道交通新建线路和运营阶段的现有线路的杂散电流治理和防护措施进行讨论.对设计阶段的新建线路而言,可采用包括优化牵引变电所位置、减小轨道纵向电阻、在道床中安装杂散电流收集系统等措施.对处于运营阶段的现有线路而言,除了采取在走行轨上并联线缆或走行轨间焊接均流线等以增大回流路径截面积措施外,通过电力电子的静止变换器(如负阻变换器等)控制回流路径杂散电流的方法也是极具潜力的治理措施;上述单元可以部署在特定点,以实现对轨道电位过高或出现初期腐蚀位置处的定点治理.     

轨道交通车辆牵引控制发展现状与趋势

从蒸汽机车的出现到现在的交流传动电力牵引,轨道交通车辆牵引控制技术随着牵引动力的发展已历经2个世纪的变革与发展。其技术发展从以牵引装置为中心,发展到现在的以平台化技术为中心的高性能控制技术,实现了牵引控制的通用化、标准化和个性化。由此,完整地讨论了其技术发展过程、现状和趋势。     

电力机车牵引电传动系统关键参数自动优化方法研究

为了使电力机车牵引电传动系统参数匹配最佳,对电力机车牵引电传动系统关键参数自动优化方法进行了研究。首先,建立了某型号电力机车牵引电传动系统的仿真模型,仿真结果证明了建模的准确性及合理性。其次,针对原模型开展试验设计(DOE)仿真,获得一簇反映系统运行规律的仿真结果,基于仿真结果建立了映射系统输入参数与输出特性的近似模型。再次,基于近似模型采用多目标粒子群优化算法进行寻优,获得了优化的设计参数。最后,对比分析几种模型仿真优化的结果,验证了采用近似模型进行全局寻优方法的效果,且在保证仿真精度的前提下,达到了极高的仿真效率。研究结果对于电力机车牵引电传动系统的高效率仿真具有参考意义。     

Increasing the efficiency of existing systems of rheostatic braking of diesel locomotives

Electrical rheostat braking is used in a large number of diesel locomotives. The article analyzes the advantages and disadvantages of the existing systems of rheostatic braking of diesel locomotives and electric rolling stock. The basic scheme of rheostatic braking of a six-axle section of the 2TE116 diesel locomotive is given. Its advantages and disadvantages are noted. The system of rheostatic braking with independent excitation, which is more widely used on the electric rolling stock of Russian railways, is analyzed in detail. A circuit- based solution of the rheostat brake system of the 2TE116U diesel locomotive is proposed that makes it possible to apply rheostatic braking without additional fuel consumption. The operation of the proposed scheme is described, as are its main advantages over the existing technical solutions. It is hypothesized that this system, without increasing the fuel consumption for traction, will also reduce the brake-pad consumption to 60%.     

店坪Y,d11牵引站负载运行分析

系统地分析了电气化铁路Y ,d11牵引站在低压侧 (a、c)相设置和不设置无功功率自动补偿情况下的负载运行。得出如果无功功率自动补偿完全补偿了牵引机车所消耗的无功功率 ,系统只供给牵引站有功功率 ,可使牵引站利用率提高 34%的结论。     

Energy-efficient algorithms for assessment of the rail-circuit operation

The voltage in a rail circuit is determined for reliable detection of the mobile unit or a train on the section of the railway track. It is proposed to use the structures of the automatic block system based on the time-division channels of status scanning of the rail circuits with subsequent signal processing by two parameters. The first parameter includes the assessment of correspondence of the code signals transmitted to the rail circuit and received from the rail circuit. The second parameter is obtained based on the analysis of the voltage at the rail-circuit output within the current and previous measurements considering the voltagechange rate. This latter parameter makes it possible to distinguish reliably the state when the rail track is occupied by the train from the random changes of the rail-circuit parameters from the influence of the external factors. The proposed algorithms permit one to reduce significantly consumption of electric energy providing operation of rail circuits.     

A comparison of the energy efficiency of the traction electric drive of alternating-current electric locomotives based on collector and asynchronous motors

An assessment of the overall performance of 3ES5K alternating-current electric locomotives with a collector drive in the regimes of traction and recuperative braking using the concrete example of a staged route between the Khabarovsk-2 and Bikin stations of the Far East Railroad is given in this article. Real traction and brake characteristics of a 3ES5H electric locomotive in the case of a cargo train of large weight and length are shown. Analysis is carried out of all the characteristics of a 3ES5H electric locomotive, and they are compared with the movement of a 2ES5 electric locomotive with an asynchronous drive. It is determined why 3ES5K electric locomotives are more power efficient than 2ES5 ones.     

Simulation Model of a Direct-Current Electric Locomotive with Commutator Traction Motors

A dc electric locomotive simulation model is considered that makes it possible to study transient and steady processes and may serve as a basis for the notion of a “digital locomotive” being implemented within the “Digital Railway” project. One of the most popular electric locomotives is selected, which is designed for pulling freight trains along long-distance railways electrified with direct current with a voltage of 3000 V. The electric locomotive model is based on a mathematical model of a collector traction engine. The model takes into account the nonlinearity of the main pole’s magnetic characteristic, as well as the effect of eddy currents in solid magnetic circuit sections on the magnetic flux variation. The model provides a mechanism for regulating motors in the course of investigations in accordance with operating conditions. The processes of resistor starting and voltage regulation by connection to resistors by means of transposition, as well as motor regulation by changing the magnetic flux, are taken into account. The possibility of using the developed model to study the traction substation–traction network–electric rolling stock system, which is determined by different operating modes of the traction network in the process of converting electrical energy into mechanical, is shown. Calculations of various locomotive operating modes in the event of failure in the contact network are carried out.     

On ensuring invariance in problems of control of rail-line conduction

In electrified transportation, the rail network is used as a return conductor of the traction network. The resistance of the components of the rail network to the traction current within the track circuits is stabilized by the rail bonds (RBs), which are classified as “welded,” “plug-in,” and “spring” rail bonds. Depending on the type of traction, copper or steel–copper RBs of various sections are used; therefore, the current conductivity of the rail line depends on the design of the rail network and the operating conditions and maintenance of the track circuits. Analysis of the distribution of failure in the track-circuit elements shows that the faults in the rail bonds are one of the leading causes of failure in the track circuits. For example, during the fourth quarter of 2016, this figure for the Kuibyshev Railroad, which is a branch of OAO Russian Railroads, was 20%, with the track circuits accounting for 57% of the total number of failure events in the devices of the railroad automation and telemechanics systems. The number of failure events has increased in 2 maintenance sections out of 11 compared with the third quarter of 2016 including failure in rail bonds. This article deals with the problems of continuous monitoring and diagnostics of the conduction of the rail lines on the basis of the principles of invariance to the disturbing actions.     

EKF在机车最优黏着控制中的应用

为了使机车工作在最优黏着状态,提出了一种基于扩展卡尔曼滤波(EKF)的滑模控制算法。首先以轮轨动力学及机车黏着模型为基础,利用EKF对机车的轮对速度和车体速度进行近似估计;然后为了克服外界干扰对系统的影响,提出了一种基于指数收敛干扰观测器的滑模控制算法;同时考虑轮轨最优蠕滑速度未知的问题,根据机车黏着模型设计一种搜索算法用于跟踪搜索当前路况的最优蠕滑速度。仿真试验结果表明,基于EKF的滑模控制算法可以有效提高机车运行的稳定性并且提高黏着利用率。     

自耦变压器供电方式的电牵引供电系统中的机车驱动谐波污染仿真研究

为了减少电气化铁路对其沿线的通信系统造成的干扰，电牵引供电系统可以采用自耦变压器供电方式。本文分析了此系统中的机车驱动谐波污染情况，建立了SS4型电力机车、牵引网及牵引变电所的模型，并通过MATLAB仿真计算出在多机条件下电力机车、牵引网及牵引变电所中的谐波电流及其谐波含量。     

双流制窄轨电力机车用异步牵引电机设计

将牵引电机应用于双流制窄轨电力机车时,由于窄轨机车轨距小,所以牵引电机安装空间异常狭小,比一般牵引电机在安装空间、电机结构、电磁负荷等方面的要求更加苛刻。针对窄轨双流制电力机车的运用特点和特殊要求进行了分析,提出了牵引电机的设计要求和关键技术难点,并对关键技术难点给出了相应的分析和解决措施。对该牵引电机的制造过程及电机试验测试情况进行了论述。试验结果表明,该牵引电机达到了设计预期,完全能满足设计要求。     

Analysis of electromagnetic processes in a homogeneous long line

Dependences between the currents and voltages at terminals of a homogeneous long line were analyzed. They make it possible to more correctly explain the changes in current and voltage in an electric-traction network when switching the thyristor arms of a rectifier–inverter converter than do conclusions obtained during replacement of a long line with a circuit with lumped parameters. An imitation model of the homogeneous low-loss long line in the MATLAB/Simulink software environment is proposed that adequately represents the propagation of incident and reflected electromagnetic waves along the line. Transfer functions are presented that approximate the frequency dependences of the specific parameters of the equivalent rail–ground loop and the overhead catenary–ground loop calculated taking into account the increase in the resistance of the wires due to the eddy currents and the surface effect. The influence of frequency dependences of the specific electric parameters of an electric-traction network calculated by various methods on the free voltage oscillation decay on the electric locomotive pantograph obtained by modeling the electromagnetic processes in the traction substation–electric traction network–electric locomotive system is revealed.     

矿用电机车矢量控制系统的研究设计

为了实现矿用电机车交流传动的高性能控制运行,提高电机车运行的可靠性,以代替传统的矿用电机车直流调阻调速和直流斩波调速,实现节能降耗,提高牵引性能。基于16位单片机dsPIC30F6010A,研制设计了一种反馈解耦型电压矢量矿用电机车交流变频调速牵引控制系统,改善了电机车低速性能,实现了电流的快速调节和无静差控制。试验结果证明了这种控制策略的有效性。     

基于功率动态分配的自动驾驶机车牵引电机节能控制

为了降低大功率机车牵引电机运行能耗,提出了一种基于牵引功率动态分配的机车牵引电机节能控制方法。首先,结合现场运行数据,建立牵引电机效率与其发挥牵引力及运行速度间的数学模型。然后,利用机车自动驾驶系统规划的区间速度及牵引力运行曲线,基于所建立的数学模型对不同牵引力分配策略下综合牵引电机能耗指标等进行计算,并选择最小化目标函数值的牵引力功率分配方案,控制机车各轴牵引力输出。最后,基于HX D 1型自动驾驶机车现场某条线路各区间运行数据,对所提方法进行仿真分析,验证了该方法的有效性。