某台汽轮发电机组轴承瓦温高原因分析

某汽轮机组轴承瓦温偏高,左右两侧温度偏差较大,对机组安全、稳定运行产生了一定影响。测试了机组停机过程中各轴承相对标高以及顶轴油压变化情况。分析结果指出,真空对#4轴承和#5轴承之间相对标高的影响较大。顶轴油压和标高监测数据都表明,抽真空后#4轴承载荷过重。轴承与轴颈之间的扬度偏差进一步导致轴承两侧瓦温不均。     

某300 MW汽轮发电机组轴承瓦温高原因分析及处理

某300 MW汽轮发电机组长期运行以来,3#轴承瓦温一直偏高,甚至在某次大修后启动过程中,其温度异常升高至110℃导致跳机,对机组安全、稳定运行产生了一定影响。通过翻瓦检查,找到了瓦温异常升高的原因,并在此基础上,通过应变法对机组轴系载荷分配和标高分布进行了测试分析。结果显示,3#轴承承载较大是引起瓦温偏高的主要原因。降低轴承标高后,机组运行指标达到优秀。     

百万机组可倾瓦油膜涡动故障分析和处理

某国产百万汽轮发电机组在调试启动中发生强烈的低频油膜涡动故障,油膜涡动发生在中压3、4号可倾瓦轴承。通过对振动特征和安装数据的分析,判断机组增加顶轴油管等因素导致轴承自位能力和稳定性降低是引起油膜涡动的主要原因。通过修改顶轴油管道布置,并对4号轴承标高和顶隙进行调整,消除了机组油膜涡动故障。     

核电汽轮机轴承温度偏高原因分析及处理

针对核电100 MW汽轮机轴承在冲转及运行期间轴承温度偏高的问题,根据GBT 21466.2-2008,对轴承温度随轴承标高的变化进行计算,并将计算结果与制造厂提供的数据进行了对比,认为主要原因为轴承标高变化、轴承瓦衬变形、轴承左右不对中等.对此,采取消除轴承标高变化、修刮消除瓦衬变、调整消除轴承左右不对中等措施后,机组冲转及满负荷运行期间轴承温度均可控制在90℃以内,轴承之间的温差更合理,提高了设备的安全裕度.     

国产600MW汽轮发电机组轴承动态标高变化规律试验研究

本文以国产600MW汽轮发电机组为研究对象,采用现场测试的方法获得各轴承座中分面处标高的动态变化规律,找到影响各轴承座标高动态标高变化的因素。研究表明:机组状态参数的变化对各轴承的标高有较大影响。机组冲转、升速过程中,轴承标高变化主要取决于轴承座本身的温度变化。本文的研究结果,对合理分配轴承的动态载荷,确保机组安全运行提供了参考依据。     

600MW汽轮机轴系调整和基础沉降分析

某台600 MW汽轮发电机组存在严重的轴承温度过高和振动不稳定隐患,在机组带负荷过程中,2号轴承金属温度已经达到95℃已影响到机组额定运行的能力。经测量检查存在轴系错位,需要进行揭缸大修、分析原因、消除缺陷、恢复机组的正常运行。通过对汽轮发电机组轴系标高的现场测量和相对标高的分析,得出轴系标高的不正常变化是导致2号轴承金属温度过高的主要原因之一。介绍了汽轮发电机组轴系的基本慨念和设计的主要内容,及轴系标高的现场测量方法,结合标高检测结果,经踪合分析,制定并实施了冷态下轴系标高调整方案,其中1号轴承标高的上抬,采用偏心轴承壳体,可满足轴系标高的调整要求。该机组大修后经运行考核,汽轮机的振动和轴承金属温度均在优良范围内。最后揭示了轴系标高的不正常变化与基础沉降之间一定的牵连关系,并提出在原基础沉降观测失控后的必要检查测量措施。     

汽轮机组标高对轴承载荷及轴封间隙影响分析

采用有限元方法建立了轴承载荷计算模型,并以国内两种典型1000 MW汽轮机组为研究对象,考虑油膜缓冲及转子弹性变形影响,比较分析标高调整对单/双支撑机组轴承载荷和轴封间隙的影响。单支撑机组相对载荷灵敏度比双支撑机组小,载荷受标高变化影响小;在油膜缓冲和转子弹性变形共同影响下,双支撑机组标高调整时,轴封间隙实际变化量小于标高调整量,调整量可以适当大一些;单支撑机组轴封间隙变化量和轴承标高调整量相当,标高调整需考虑对轴封间隙的影响。研究结果为电厂汽轮机组轴系标高调整提供了依据。     

300MW汽轮机低速碾瓦的分析及处理

针对300MW汽轮机在停机过程中,改进型可倾瓦轴承温度异常升高出现低速碾瓦的特点和原因进行分析,通过降低轴承标高、加大轴瓦进油节流孔直径等技术措施,彻底解决了汽轮机低速碾瓦的故障,取得了非常明显的效果。     

大型汽轮发电机组标高对轴承载荷的影响

大型汽轮发电机组稳定性影响因素中,标高是非常重要的一个因素,轴系的振动特性是其主要指标,振动的大小又受载荷分配的影响,而标高的确定又影响着轴承载荷的分配。利用传递矩阵法计算轴系的标高,并结合某1 000MW机组对轴承载荷对标高变化灵敏度进行分析。     

300MW汽轮机停机过程中轴瓦异常的分析及处理

某电厂3号机组在停机过程出现1号轴承轴振大及2号轴瓦温度突然上升的异常现象,经检查分析,认为轴封供汽温度下降使接近汽封段的转子发生临时热变形与轴封发生碰磨且在打闸停机惰走过临界后加剧是造成1号轴承轴振大的原因;2号轴承标高在运行中受温度影响产生上抬,且其轴承油膜失稳导致轴承与轴颈发生干磨是造成2号轴瓦温度突然上升的主要...     

基于α逆系统理论磁轴承数学模型及控制系统

采用α阶逆系统方法,对轴向混合磁轴承这一非线性控制对象进行线性化控制研究。介绍了轴向混合磁轴承的结构并分析了其工作原理,推导出轴向混合磁轴承吸力方程。在阐述了α阶逆系统方法的基础上,针对轴向混合磁轴承动力学模型分析了基于α阶逆系统方法线性化控制的可行性,推导出基于α阶逆系统方法的线性化算法,并设计了闭环系统控制器。最后利用Matlab软件环境,构建了仿真系统,针对系统的阶跃响应、转子起浮、抗干扰性能等进行了仿真和分析。仿真试验结果表明α阶逆系统策略能够对混合磁轴承数学模型精确线性化,设计的闭环控制系统具有良好的动、静态性能。     

PC-controlled laser diode system application

This paper presents a system with a personal-computer (PC)-controlled laser-diode beam to make film exposures for generating 256 gray-level images. The hardware equipment of this system includes an IBM PC, an 8255 interface card, and an XY table. Control software is developed to receive image data from commercially available software, such as PAINT SHOP, then convert them to signals for the laser diode and XY table. The gray level of each pixel (picture element) in an image file is represented by an 8-bit binary number. Two ways of control are demonstrated. One way uses this 8-bit number as a parameter for timing delay when the laser diode is on with a constant power output. The other way uses this 8-bit number to go through a D/A converter to control the laser diode for outputting beams with varying intensity. This way may gain higher operation speed, but requires extra hardware. There are two potential applications for this system. One is direct image exposure of yellow, magenta, cyan, and black for all image processing software data outputs, as long as their format is available. The other is for an educational training program to demonstrate the technologies of integrating computer, laser, and color printing     

LTE电力无线专网多业务承载方案研究

从分析电力通信系统的建设现状与存在的问题出发,论述了多业务承载的基本原理与一般方法,基于LTE网络结构及其在电力系统中的部署模式,针对电力通信系统的多业务承载需求。提出了一种电力LTE无线系统的多业务承载解决方案。该方案可以为电力多业务承载通信网络的设计提供思路,在未来LTE网络建设中有一定的应用价值。     

基于机器视觉的铁路货车滚动轴承表面缺陷检测

针对目前轴承缺陷检测操作复杂、速度慢、精确度低等缺点,利用数字图像处理技术,设计出基于CCD成像技术的轴承缺陷非接触在线检测系统,讨论了系统中灯光、摄像机的安装位置对成像的影响,提出利用图像特征的麻点的检测方法,该系统能对麻点缺陷进行识别,对缺陷的区域进行测定。现场测试表明,系统操作简单、速度快、精确度高、为轴承缺陷检测提供了一种新方法。     

Development and field test of a laser-based nonintrusive detection system for identification of vehicles on the highway

A real-time laser-based nonintrusive detection system has been developed for the measurement of true travel time of vehicles on the highway. The detection system uses a laser line that is projected onto the ground as a probe. The reflected light is collected and focused into a photodiode array by an optical system. Vehicle presence is detected based on the absence of reflected laser light. By placing two identical laser/sensor pairs at a known distance apart, the speeds of both the front and rear of a vehicle are measured based on the times when each sensor is triggered. The length of each vehicle is determined by using these speed measurements and the residence time of the vehicle under each sensor. Using real-time software, the speed, acceleration, and length of a detected vehicle can be calculated and displayed simultaneously. A new prototype system has been tested on the highway with different types of vehicles and scenarios, and the results are presented here. The tests have also been carried out for different weather conditions and road materials. The results indicate that the laser system operates well under real highway conditions.     

Characteristics of axial force and rotating torque and their control of permanent magnet type axial gap self‐bearing motor

This paper introduces an axial gap type self‐bearing motor. It is intended for a disk type flat motor to have both functions of rotation and axial position control. This motor is simple in construction and requires a simple control system. A permanent magnet type motor is analyzed theoretically and tested experimentally. The torque characteristics of the tested motor are measured at various values of axial force and air gap. Independent control of the axial force and torque is introduced for the servo motor control and synchronous motor control. The results show the high possibility of the proposed motor and control system. © 2000 Scripta Technica, Electr Eng Jpn, 132(1): 81–91, 2000     

原子干涉重力仪集成光源系统综述

高精度重力测量是进行惯性导航、大地测量、空间科学、海洋探测、基础物理研究的重要观测手段,高精度的重力仪一直是科学研究追求的目标。原子干涉重力仪能够提供uGal量级的绝对重力加速度值,是获取高精度重力信息的重要仪器之一,其集成光源系统的设计及实现对其实用化和商业化具有重要意义。首先介绍原子干涉重力仪激光系统的输出需求,然后对国内外典型集成光源系统的相关研究发展进行综述,分别介绍了基于自由空间和光纤传输的两种光源系统的实现方案和发展现状,重点阐述了其稳频、跳频、稳功率等关键技术。最后,对原子干涉重力仪集成光源系统的进行了总结与展望。     

Three‐dimensional vibration characteristics of the permanent magnet–HTSC magnetic bearing

The three‐dimensional vibration of the rotor in a permanent magnet– HTSC magnetic bearing system is studied. We have developed a magnetic bearing system which can revolve at up to 12,000 rpm, and three‐dimensional vibration of the rotor is measured with laser displacement sensors. To consider the rotor vibration in a mechanical resonance state, the static lateral and vertical pinning forces of the magnetic bearing are measured. The results are used to obtain the resonant frequency. There are two factors in the mechanical resonance caused by the magnetic bearing. One is the lateral equivalent spring coefficient and the other is the vertical equivalent spring coefficient. The influence of mechanical resonance caused by the lateral spring coefficient is large, and that of the vertical one is small. The three‐dimensional vibration of the rotor position around the mechanical resonant frequency is measured. Because the revolution of the rotor increases the lateral force to the center, the resonant frequency obtained in a free revolution experiment is larger than that obtained from pinning force measurement. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 165(3): 58–64, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20586     

激光供电在串补测量控制系统中的应用

随着激光技术的飞速发展,激光供电技术在串补保护测量控制系统中的应用越来越广泛。文章介绍了激光供电的原理及其在电力系统串补保护测量控制系统中的应用,分析了各串补站保护测量控制的激光供电设备在运行中出现的问题．找出了激光供电设备的运行及维护方法。不断地改进激光供电系统,提高激光供电设备运行可靠性,保证了串补保护测量控制系统的稳定运行。     

相位式激光测宽仪的设计和实现

自60年代初期激光的出现,激光测距取代了传统的测距方法成为测距系统的主流.本文所设计的激光测宽仪实际上是在激光测距的基础上实现双向测量,是激光测距的一个应用,旨在设计一套体形轻巧、性价比高、测距精度较高的双向测距系统,所采用的是相位法,即对半导体激光器直接调制使激光连续发射,通过测量往返信号之间的相位差实现距离的测量.文中采用了直接数字频率合成技术(DDS),保证了主振和本振频率的准确性也避免了传统测距系统中正弦发生信号所出现的频率漂移和相位抖动等问题,实验结果比较理想.