交流传动电力机车主电路对牵引变压器的影响及防治措施初探

交流传动电力机车的主逆变器,由于功率开关器件的频繁动作,不可避免地会产生谐波,高次谐波对牵引变压器短路阻抗有较大的影响：交流传动机车的再生制动,会引起网压的波动和网压上升。这些在交流牵引中比较突出的问题,都可能引起的牵引变压器牵引绕组过励磁以及直流磁化。在设计牵引变压器时需要进行分析并给出相应的解决方法。     

电力机车电磁辐射的机理及对周边环境的影响

建设完善高速铁路网已成为我国的国家战略，其对于我国的经济社会发展都有着重要的意义。但在高速铁路网快速发展的同时，也带来一些附加影响亟待解决。高速铁路行驶的都是电力机车，电力机车在运行的过程中，均会对外发射电磁辐射。本文从电网对电力机车的供电系统为切入点，描述了电力机车产生电磁辐射的机理，并就铁道沿线受电磁辐射影响主要设备进行了分析，并提出了相应的对策。     

SS4型电力机车预备电路的改进

SS4型电力机车在调速手柄高级位时如果出现劈相机脱扣跳开,造成劈相机停止工作,同时各通风机也停止工作,但是从电路上预备电路仍然能够完成,容易造成牵引电机、整流柜等烧损,建议对预备电路进行改进。     

谐波对电气设备的影响及应对

谐波是在非线性阻抗特性的电力设备供电过程中产生的,它能够破坏电力质量,影响电气设备的的正常运转,特别是对变压器、电容器和电机造成重要影响。对谐波的产生及其对电气设备的影响进行分析,并且探讨相应的应对方法。希望研究对于提高电气设备的供电质量,减少谐波危害能够产生一定的参考和借鉴作用。     

谐波对低压电力系统的影响

通过对电力系统中谐波产生原因的说明,描述谐波在低压配电系统中的影响。     

谐波对感应式电能表影响的新进展

本文主要研究谐波源（包括奇次和偶次谐波）对感应式电能表计量电能的影响。     

试论电力系统谐波对电力计量的影响

谐波是电力系统中不能完全杜绝的干扰现象,谐波的产生是电力系统中主要设备的硬件因素引起的,在不能避免的情况下只能通过技术改进对其进行有限的控制。因此谐波对电力计量也会产生实时的影响,各种电器设备都会产生谐波并干扰计量电表。     

浅析谐波对电能计量的影响

本文从电力谐波对电网的危害及其对电力企业经营效益的影响入手,通过电力谐波对普通电子式电能表和感应式电能表电能计量的对比,分析了电力谐波对电能计量的影响,推广电力谐波电能计量的必性,并提出改造对策和展望。     

谐波对相位测量的影响

本文着重介绍谐波对以测量过零时间间隔、基波相位差、有效值功率与视在功率之比为基础的３种工作原理的相位测量仪表的影响机制和使用中应注意的问题。     

谐波对电能计量的影响

文章对谐波的产生和算法进行了简单的介绍,对各次谐波能够精确计算;并且通过对电子式电能表的工作原理分析可知,在电压和电流都发生畸变时,仍能准确计量。但它也把谐波功率和基波功率等量计算,因此,它的计量误差比感应式电能表大。     

牵引变压器模糊故障诊断技术

牵引变压器是牵引供电系统的重要组成部分之一，对其DGA成分和含量进行在线监测并进行故障判断，能有效地提高电气化铁路运行可靠性。目前对变压器的故障性质判断大多是根据IEC三比值法进行的。而实践中，一些DGA结果与已存在的IEC编码不符，或造成缺码现象。论文采用模糊三比值诊断法进行故障性质判断能有效地解决这一问题。     

高原环境适应性改进HXD1C机车网侧柜的设计与分析

文章以新研发的高原环境适应性改进HXD1C机车网侧柜为例,重点对网侧柜设计的参数修正、电气元件布置、柜体安全防护、接地保护等方面进行了分析和介绍。     

浅析变电电气设备安装调试与技术分析

文章主要讲述了电气设备安装、调试技术经验与总结,涉及到变电站的主要组成部分,分别是电力变压器的安装与调试工作,隔离开关的安装与维护,以及电力电缆敷设需要注意的几点意见。     

内燃机车微机控制系统检测装置

阐述了虚拟仪器的基本概念，详细描述了基于虚拟仪器内燃机车微机控制系统检测装置硬件构成和软件实现方法。     

内燃机车恒功试验监测模块实时性可视化设计

介绍了一种用于东风系列内燃机车恒功试验的监测模块。着重讨论了为实现恒功试验中实时性可视化监测所采取的方法及其软件设计。     

热处理条件对氧化石墨结构和导电性能的影响

氧化石墨是石墨的氧化产物．由于它的碳层表面引入了很多极性功能团，使得很多分子都能够嵌入其层间形成纳米复合物，但也正是这些功能团使得它散失了石墨良好的导电性。为了考察氧化石墨受热处理后还原的可能性，通过X-射线衍射、扫描电镜、红外光谱分析以及元素分析等手段研究了氧化石墨在不同热处理条件下的结构变化。研究发现热处理时的升温速度对氧化石墨的结构影响很大，快速升温时，氧化石墨迅速分解，发生膨胀形成类似于膨胀石墨的含有丰富的50nm至5μm左右孔洞的一种结构；而当缓慢升温时，氧化石墨随着热处理温度的升高，逐渐恢复成类似于石墨的结构，同时电导率也随热处理温度的升高而提高，当热处理温度高于180℃时，电导率大于1S／cm。这些结果表明利用氧化石墨作为前驱体，通过先制备聚合物／氧化石墨纳米复合物后经热处理来得到导电性的聚合物／碳纳米复合材料是可行的。     

The impact of contract parameters on the supply chain performance under different power constellations

Reporting forecast data is a common method used to improve the functioning of supply chains (SCs) and to reduce supply shortages. Customers tend to report the maximum possible demand as a forecast if restrictions are missing. Such a forecast is useless for suppliers. Hence, special contracts are needed to enhance the value of forecast data and therefore the cooperation between SC partners. In this paper, such a contract is presented. It encourages the customer to report a more realistic forecast. Deviations from the reported forecast are punished in different ways: If the customer reported too much and wants to release less than what was reported, he has to pay a penalty. On the other hand, the customer has the flexibility to purchase more than reported to meet the demand on his outlet but at the cost of an additional fee. This paper analyses how different contract parameters affect the performance of the SC, in particular when the bargaining power of customer and supplier is not equally distributed. Results show that the supplier and therefore the SC is better off if the supplier leaves the contractual cost parameters untouched but hides the true value of flexibility, especially when the customer is less powerful than the supplier.     

The effect of water saturation degree on the electrical properties of cement-based porous material

Electrical properties can be important indicators for durability of cement-based porous materials (CBPMs). This study seeks to deepen the understanding of the effect of water saturation degree on the electrical properties of CBPMs. Taking into account the joint conduction effects of the phases of pore solution and surface adsorption, and the determination by the quadratic deviation factor, we analyze the experimental data in the literature and evaluate the important parameters, i.e. the percolation threshold and Archie exponent. The contribution of the adsorbed phase to the total electrical properties is minor in high water saturation degree region, and then becomes heavily important as water content approaches the threshold. More thoughtful interpretation of the electrical properties of CBPMs should be conducted to correlate the threshold and exponent data to the micro- and pore structures and the transport properties.     

电气化重载铁路长供电臂末端网压提升技术应用与研究

本文简述了神朔电气化重载铁路长供电臂末端网压跌落的原因及理论分析,对比分析了接触网电压损失和变电所电压损失的网压提升方法。结合神朔铁路的实际特性,提出了一种在供电臂末端装设动态无功补偿装置的提升网压的方法,并探讨了在供电臂末端进行补偿的优越性,通过对比该装置投运前后的补偿效果,该补偿装置在重载时能有效地将供电臂末端电压提升了8kV,同时系统功率因数保持到0．98以上。     

The impact of total quality management on supply chain management and firm's supply performance

This research investigates the relationships among total quality management practices (TQMP), supply chain management practices (SCMP) and firm's supply performance (FSP) in the automotive industry in Thailand. The measurement instruments for SCMP, TQMP and FSP were developed based on an extensive literature review and verified by experts, pilot test and various statistical techniques to ensure reliability and validity in structural equation modeling constructs. The hypothesized model was tested through a path analysis. Qualitative case studies of two large first-tier automotive suppliers were conducted to obtain more in-depth information. We found that the set of SCMP, TQMP and FSP measures are reliable and valid for Thailand's automotive industry. TQMP not only has a significant direct positive impact on SCMP and on FSP but also a significant indirect positive impact on FSP through SCMP.