Study on wear characteristics and authorized limits of switch rails of high-speed turnout

Purpose-It is quite universal for high-speed turnouts to be exposed to the wear of the stock rail of the switch rail during the service process.The wear will cause the change of railhead profile and the relative positions of the switch rail and the stock rail,which will directly affect the wheel-rail contact state and wheel load transition when a train passes the turnout and will further impose serious impacts on the safety and stability of train operation.The purpose of this paper is to provide suggestions for wear management of high-speed turnout.Design/methodology/approach-The actual wear characteristics of switch rails of high-speed turnouts in different guiding directions were studied based on the monitoring results on site;the authorized wear limits for the switch rails of high-speed turnout were studied through derailment risk analysis and switch rail strength analysis.Findings-The results show that:the major factor for the service life of a curved switch rail is the lateral wear.The wear characteristics of the curved switch rail of a facing turnout are significantly different from those of a trailing turnout.To be specific,the lateral wear of the curved switch rail mainly occurs in the narrower section at its front end for a trailing turnout,but in the wider section at its rear end when for a facing turnout.The maximum lateral wear of a dismounted switch rail from a trailing turnout is found on the 15-mm wide section and is 3.9 mm,which does not reach the specified limit of 6 mm.For comparison,the lateral wear of a dismounted switch rail from a facing turnout is found from the 35-mm wide section to the full-width section and is greater than 7.5 mm,which exceeds the specified limit.Based on this,in addition to meeting the requirements of maintenance rules,the allowed wear of switch rails of high-speed turnout shall be so that the dangerous area with a tangent angle of wheel profile smaller than 43.68 will not contact the switch rail when the wheel is lifted by 2 mm.Accordingly,the lateral wear limit at the 5-mm wide section of the curved switch rail shall be reduced from 6 mm(as specified)to 3.5 mm.Originality/value-The work in this paper is of reference significance to the research on the development law of rail wear in high-speed turnout area and the formulation of relevant standards.

Analysis of Fault Arc in High-Speed Switch Applied in Hybrid Circuit Breaker

The behavior of fault arc in a high-speed switch （HSS） has been studied theoretically and experimentally. A simplified HSS setup is designed to support this work. A two-dimensional arc model is developed to analyze the characteristics of fault arc based on magnetic-hydrodynamic （MHD） theory. The advantage of such a model is that the thermal transfer coefficient can be determined by depending on the numerical method alone. The influence of net emission coefficients （NEC） radiation model and P1 model on fault arc is analyzed in detail. Results show that NEC model predicts more radiation energy and less pressure rise without the re-absorption effect considered. As a consequence, P1 model is more suitable to calculate the pressure rise caused by fault arc. Finally, the pressure rise during longer arcing time for different arc currents is predicted.

Design and Implementation of Dynamic High-Speed Switches in Super Base Station Architectures

Novel centralized base station architectures integrating computation and communication functionalities have become important for the development of future mobile communication networks.Therefore,the development of dynamic high-speed interconnections between baseband units(BBUs)and remote radio heads(RRHs)is vital in centralized base station design.Herein,dynamic high-speed switches(HSSs)connecting BBUs and RRHs were designed for a centralized base station architecture.We analyzed the characteristics of actual traffic and introduced a switch traffic model suitable for the super base station architecture.Then,we proposed a data-priority-aware(DPA)scheduling algorithm based on the traffic model.Lastly,we developed the dynamic HSS model based on the OPNET platform and the prototype based on FPGA.Our results show that the DPA achieves close to 100%throughput with lower latency and provides better run-time complexity than iOCF and HE-iSLIP,thereby demonstrating that the proposed switch system can be adopted in centralized base station architectures.

Fragility of disconnect switch subjected to random earthquake ground motions

A fragility calculation scheme is estabtished in this paper for porcelain-type equipments subjected to random earthquake ground motions. All steps of the method are illustrated by the seismic damage analysis of GW4-110 disconnect switch. The model of the equipment is built applying the finite element method with flexible joints, and the seismic response of the equipment is analyzed using elastic time history method. On the base, according to the strength damage index and Monte-Carlo Method, the seismic damage ratios are counted and the seismic fragility curves are presented. Then the seismic damage of GW4-110 disconnect switch can be predicted.

Development of High-Speed On-Of Valves and Their Applications

With the widespread application of the computer and microelectronic technology in the industry,digitization becomes the inevitable developing trend of the hydraulic technology.Digitization of the hydraulic components is critical in the digital hydraulic technology.High-speed on-of valves(HSVs)which convert a train of input pulses into the fast and accurate switching between the on and of states belong to widely used basic digital hydraulic elements.In some ways,the characteristics of the HSVs determine the performance of the digital hydraulic systems.This paper discusses the development of HSVs and their applications.First,the HSVs with innovative structures which is classifed into direct drive valves and pilot operated valves are discussed,with the emphasis on their performance.Then,an overview of HSVs with intelligent materials is presented with considering of the switching frequency and fow capacity.Finally,the applications of the HSVs are reviewed,including digital hydraulic components with the integration of the HSVs and digital hydraulic systems controlled by the HSVs.

一种基于磁耦合转移原理的10kV直流断路器

直流电流没有自然过零点,因此开断直流短路电流比开断交流短路电流更为困难。本文介绍一种基于磁耦合电流转移原理的中压10kV直流断路器拓扑方案,该断路器可实现对15kA直流电流的快速开断。首先,对直流断路器原理和控制逻辑进行介绍;然后,根据拓扑方案提出快速机械开关、电力电子开关、磁耦合装置等核心部件的设计思路;最后,搭建仿真模型对该方案进行仿真分析,模拟不同工况下的开断情况,仿真结果验证了该方案的有效性。

柱上隔离开关不同镀银层参数的导电及磨损性能实验研究

为提高柱上隔离开关的导电和耐摩抗磨能力,行业目前主要采用在其接触部位进行镀银处理。但镀银层厚度、粗糙度和硬度对柱上隔离开关的导电性、磨损度的影响缺乏研究,亟需给出更加合理的设计标准。本文以GW-9系列柱上隔离开关为研究对象,通过投制试验样件,研究了镀银层厚度、粗糙度、硬度及涂覆电力复合脂对其接触部位导电性及摩擦磨损性能的影响。研究结果表明:柱上隔离开关接触部位镀银能够提高接触表面的导电性和摩擦性能,镀银层的粗糙度和硬度对接触部位的导电性具有一定影响,不同镀银层厚度对接触部位导电性的影响较小,电力复合脂润滑能够显著提高隔离开关接触部位的抗磨性能。研究结果可为隔离开关电接触材料参数的标准化设计提供理论与实验依据。

基于锰锌铁氧体材料的隔离开关电磁骚扰故障检测分析

锰锌铁氧体是线圈的重要材料,而共模扼流线圈特性是隔离开关故障分析的主要依据。研究针对隔离开关电磁骚扰故障,提出了幂函数表示电感的频率变化特性,建立共模流线圈的等效电路,由于频率特性、阻抗是锰锌铁氧体材料的特殊性质,研究基于此优化电磁干扰(Electro Magnetic Interference)滤波器的滤波性能。另外,此次研究了关于瞬态骚扰过程计算的隔离开关故障分析,计算刀臂的分闸与合闸操作中产生的击穿电压变化和时间点。为了验证算法的相关性能,设计仿真实验进行验证。结果表明,确定基于锰锌铁氧体共模扼流圈的等效模型,包括电感、磁损耗和等效阻抗,1-0.0087 f-0.122的耦合系数、4 pF时绕组的寄生电容、35 mH时线圈自身电感和0.21Ω的绕组铜损耗等效阻抗。可见基于锰锌铁氧体材料的隔离开关,电磁骚扰故障检测分析更加准确和详细,对于电路故障分析具有参考和研究意义。

Interruption Characteristics of High-speed Switches in 500 kV Fault Current Limiter with High Coupled Split Reactance

A 500 kV high-voltage AC fault current limiter(FCL)based on a high coupled split reactor(HCSR)is pro-posed by the National key R&D project team.Low impedance under normal conditions and high impedance under short-circuit conditions are accomplished by the cooperation of HCSR and high-speed switches.High-speed switches play an important role in current limiting processes,thus interruption characteristics of the high-speed switch in the 500 kV FCL are studied in this paper.The simulation model of the FCL and the external equivalent power grid are established.The short-circuit current and recovery voltage characteristics of the high-speed switch in FCL are simulated.The results show that maximum DC component of the short-circuit current of the high-speed switch reaches 91%,the maximum peak value is 118 kA,and the longest arcing time is 14.8 ms.There is a discontinuity in the curve of the short-circuit current peak and arcing time as a function of the short-circuit occurrence time;the peak recovery voltage of a single break of the high-speed switch has a maximum value of 87.5 kV under a three-phase ungrounded short-circuit condition,and the rate of rise of recovery voltage is o.22 kV/s.The recovery voltage peak shows a period change with the short-circuit occurrence time,and the period is 10 ms.The effects of the shunt capacitor value and short-circuit ground resistance on the recovery voltage of high-speed switching are also studied.The research can be used for reference by R&D personnel and testersof500kVFCLs.Index Terms-Fault current limiter(FCL),high coupled split reactor(HCSR),high-speed switch,interruption characteristics,short circuit current.

基于电机驱动技术的三工位隔离/接地开关操作机构设计

针对目前高压隔离开关在操作过程中存在的可控性差,难以实现动触头的精准控制,控制回路复杂,分合闸指令需要通过继电器输入,容易出现隔离开关误动的问题,提出了一种集成化、智能化、可强电输入输出、双闭环精准控制的隔离/接地开关电机直驱操作机构。该操作机构根据隔离开关动触头运动曲线,通过对电机电流、速度、位置信号进行采集,运用SVPWM电压矢量控制算法,实现对隔离/接地开关运动过程的精准控制。试验结果表明:该操作机构从收到动作信号到动作结束时间短,启动后可在很短时间内达到预设速度,整个动作过程中机构输出稳定、波动小,有效提高了隔离/接地开关的可靠性。

一种新型移动储能充放电装置

针对当前电动充电需求增加和台区用能面临的一系列问题,提出一种新型移动储能充放电装置。该装置以标准集装箱为载体,集成电动汽车充电设施、储能系统、并离网切换装置、供电接口装置等,实现高适应性、高安全性、高机动性,在移动充电、保供电、台区增容、削峰填谷等领域有着广阔的应用前景。

地铁接触网隔离开关直流传动电机监控装置的设计与应用

目的:地铁接触网隔离开关是接触网停、送电控制的重要部件,隔离开关的稳定分合工作直接关系到停、送电流程的准确执行。因此,要提升接触网系统隔离开关设备的故障侦测手段,尽早发现故障的前期潜在表征,降低该类问题的发生概率。方法:运营维护中,隔离开关故障可区分为机械类故障与电气类故障。对于多数故障部件的拆解分析显示,隔离开关设备在故障前存在诸多肉眼不易察觉的潜在隐患。及早发现、提先预警、提前介入,可以在很大程度上降低故障的发生并提升设备运行的可靠性。本项目的技术路线为通过在电机主回路中前置采样单元,开展开关电机分合时的电流-时间曲线录波,之后通过后台数字处理单元学习不同情况下的故障波形并开展关键特征比对,最终输出异常结果形成预警。结果及结论:本项目通过模拟隔离开关的典型故障,利用示波器开展设计与模型验证,最终制作出成熟、可靠的工业产品,大幅度地提升了现场在线设备的可靠性。

基于电流峰面积及时间特性的隔离开关故障诊断系统设计

为了实现高压隔离开关机械故障诊断,设计了电机电流检测系统并实时采集了GW4B-252 DW型隔离开关分合闸过程中的电流信号,分析了隔离开关分合闸不到位、运动部件卡涩等机械故障情况下的电机电流信号特征,提出了基于电流峰面积分析和时间特性对比的隔离开关机械故障诊断流程。研究结果表明,当隔离开关发生机械故障时,驱动电机电流波形发生畸变,对应的电流峰面积和时间特性发生明显改变,由此可判断出相应的故障类型。该方法具有广泛适用性,从而可提高设备运行的可靠性。

基于电磁感应原理的隔离开关分合到位判断方法

隔离开关分合状况的智能、可靠判断对于电网调度发挥着重要作用。为满足隔离开关全面调度遥控操作的需求,至少需要2个非同源指示发生对应变化,为此提出了一种基于电磁感应原理的隔离开关分合到位判断方法,其判断结果可作为辅助判据。该方法通过在动触头侧安装无源接收线圈及电压感知元件,在静触头侧安装磁能发射线圈及控制装置,基于磁耦合谐振式无线电能传输原理,通过辨识开关分合运动带来发射、接收线圈间互感变化引起的感应电压变化实现隔离开关位置判别。研究首先分析了基于电磁感应原理的开关分合到位判别方法的原理及工作逻辑,然后建立系统模型,给出了参数设计准则及流程,最后搭建实验样机对所提方法进行验证。仿真及实验结果均表明,隔离开关动作过程中两线圈互感与感应电压间存在映射关系,通过设定合理的感应电压阈值,可以实现隔离开关分合状态的判断,验证了所提方法的有效性。

数据中心接地方式、“断零”和四极开关选用问题的综合思考

通过对案例和架构的分析,探讨分析数据中心变配电系统接地方式、“断零”问题及四极开关选用等业界难点问题,提出数据中心电气架构相关难点问题交织情况的解决需要综合思考,从而找到最佳的技术路线及解决方案。

330 kV GIS隔离开关操作产生的VFTO电磁骚扰特性研究

针对GIS中隔离开关分合闸引起的电磁骚扰特性规律,建立了气体绝缘金属封闭开关设备(gas insulated switchgear,GIS)等效模型,并开展了330 k V真型变电站模拟试验场GIS隔离开关分合操作测试试验。通过仿真分析表明:合闸时VFTO脉冲群表现为前疏后密,分闸时表现为前密后疏,合闸过程VFTO最大过电压达到1.39 pu,分闸操作产生的VFTO过电压达到1.38 pu,合闸频谱主要在9.7 MHz、91 MHz存在尖峰,分闸频谱主要在60 kHz、9.7 MHz、92 MHz存在尖峰,波形特征实测与理论分析一致。

GIS双断口隔离开关不停电试验电场分布及击穿特性

共气室结构的双断口隔离开关(double-fracture disconnect switch,DDS)在不停电耐压试验过程中存在因试验侧断口击穿而影响运行侧断口绝缘性能的风险,在设计阶段需要对其电场分布和击穿特性进行研究。为此,以新研发的110 kV三相共箱式GIS双断口隔离开关为例,采用有限元方法对电场进行仿真分析,得到其在现场不停电工频耐压试验中的内部电场强度分布。根据电场的计算结果,采用基于汤逊放电理论的击穿判据,研究不停电试验中两个断口的击穿特性,证明了在DDS现场不停电交流耐压试验过程中,试验侧断口击穿不会对运行侧的绝缘性能造成影响。研究结果可以为在运的DDS二期扩建时的不停电扩建与现场绝缘试验工作提供安全保证的理论支撑,也为未来新型DDS设备研发过程中的绝缘校核提供了更加翔实的理论依据。

GW7D-1100(W)型隔离开关提前翻转故障改进措施

某变电站的一组三柱水平旋转式GW7D-1100(W)隔离开关出现合闸操作时主刀臂提前翻转,动触头未能进入主静触头,合闸不成功,在进行分闸操作后主刀臂亦无法旋转至原状态,影响了送电工作。基于此,为避免隔离开关合闸提前翻转动作故障提出了一种改进措施,改进后的刀闸无须再进行登高作业,在一定程度上也增加了人员操作的安全性。

鼓风机在线倒机操作的优化研究

现代化钢铁企业常规配套有多座高炉、多台鼓风机,为确保高炉冶炼连续性,合车解列操作已成为衡量风机操作人员技能水平一项重要操作。通过深度剖析鼓风机离线倒机、在线合车解列操作的弊端,并据此对在线合车解列方法提出改进措施,解决了在线合车解列难点问题,保证了鼓风机在线切换状态下高炉生产的稳定性,在钢铁行业有极强的推广价值。

一起GIS隔离开关合闸不到位故障的原因分析

介绍了一起GIS隔离开关合闸不到位引起的GIS放电故障,根据现场检查与解体分析,最终确定故障原因为厂家安装人员将隔离开关B相定位销调整后,未对A、C相定位销与定位孔位置进行确认,导致A、C相分合闸时动触头行程发生变化,C相合闸不到位引起放电。最后结合现场实际,列出了防范措施,以预防此类故障的再次发生。