大型核电汽轮发电机转子通风系统 流动特性数值模拟

核电汽轮发电机是核能发电的主要设备之一,其通风冷却性能是影响核电机组安全运行的重要因素。转子采用轴向—径向通风是大型核电汽轮发电机常用的通风系统之一。根据计算流体力学（CFD）的基本原理,对大型核电汽轮发电机转子通风系统的通风结构和性能进行了分析,建立了转子通风系统内冷却气体流动的三维计算模型,确定了相应的边界条件,进行了数值计算和分析,得到了该汽轮发电机转子线圈直线段各通风沟内冷却气体的流量分配规律,气隙内的流场及静压分布规律。研究结果可为汽轮发电机转子通风系统结构优化及温升计算提供参考。     

发电机氢气温度异常的事故处理及原因分析

发电机氢冷系统的作用是通过在发电机内部流通的氢气来冷却发电机的转子及定子铁芯等,并通过位于发电机顶部的冷却器来完成氢气的冷却。对于氢冷机组,发电机氢气冷却器如果不能正常工作,机组可以短时间运行,一旦出现氢气系统超压、发电机定子线圈、铁芯等部件有超温的趋势时应立即采取相应措施,甚至停机。通过分析一起氢气温度异常事故的处理过程,可以总结出,电厂设备从施工到调试,到验收,再到运行,每一道工序都必须按照相关标准严禁、认真地执行;加强对技术人员的培训工作,提高技术人员处理突发事件的能力;如果需要可让生产单位人员及早介入,既能熟悉系统了解设备性能,还能对施工及调试等过程进行监督,以保证整体工程的质量。     

390H全氢冷发电机定子接地故障的分析及处理

介绍了390H全氢冷发电机结构特点,分析了定子线圈端部接地故障的原因,采取了合理的修复措施,提出日常维护中需加强定子槽楔和铁芯紧密度的检查.     

1000MW汽轮发电机气隙流场的数值模拟

针对1 000MW系列水氢氢汽轮发电机,对发电机的气隙进行2D建模,对气隙及径向风道采用RNG k-ε湍流模型应用多重坐标系进行数值模拟,对发电机的气隙流场进行分析,并用模拟所得数据计算转子同一风道不同匝线棒中的气体流量得出流量分布规律,发现各线棒中气体流量较为均匀,为发电机的通风系统的设计提供依据.     

660 MW发电机漏氢原因分析与处理对策

鸳鸯湖电厂1号发电机为QFSN6602型汽轮发电机,采用水氢氢冷却方式,正常运行时发电机内氢压高于定子冷却水压力;当定子线棒存在裂纹并发生泄露时,将会导致定子冷却水含氢量急剧升高,从而使定子冷却水进入发电机造成发电机烧损.定子冷却水箱安装氢气泄露检测仪,在线检测定子冷却水箱内氢气含量,当氢气浓度达2%时就会报警.讨论了发电机定子冷却水箱内检测仪报警后的原因分析及处理,为同类机组类似故障处理提供参考.     

汽轮发电机转子风斗流动特性的实验研究

在转子气隙取气通风系统中,风斗的取风与引风性能直接影响系统的通风冷却效果.对汽轮发电机转子气隙取气斜流通风系统进行了静态实验模拟,研究了结构参数和结构型式对转子进、出风斗取风性能和引风性能的影响规律,为汽轮发电机转子风斗的优化设计提供了可靠依据.     

汽轮发电机转子风斗流动特性的实验研究

在抟子气隙取气通风系统中，风斗的取风与引风性能直接影响系统的通风冷却效果。对汽轮发电机转子气隙取气斜流通风系统进行了静态实验模拟，研究了结构参数和结构型式对转子进、出风斗取风性能和引风性能的影响规律，为汽轮发电机转子风斗的优化设计提供可靠的依据。     

大型水内冷汽轮发电机定子线棒腐蚀堵塞故障分析

大型汽轮发电机定子线棒的堵塞是水内冷汽轮发电机定子常见的故障之一。叙述了600 MW水氢氢汽轮发电机定子线棒堵塞的故障原因,提出,消除故障的措施。     

大型汽轮发电机定子线圈F级绝缘寿命预测方法的研究

介绍了大型汽轮发电机定子线圈F级绝缘的老化因子与加速寿命试验方法,对电老化与广义热老化的加速寿命试验数据进行了统计分析;用威布尔分布对F级绝缘的电老化和广义热老化的加速寿命试验数据进行了描述;应用可靠性统计和非线性回归方法确定了F级绝缘电老化与广义热老化寿命计算公式的特征参数;依据寿命损耗累积理论,介绍了电老化与广义热老化同时作用的汽轮发电机定子线圈F级绝缘寿命的预测方法和水冷定子线圈F级绝缘寿命损耗的分配方案.采用2倍额定电压2 UN和3倍额定电压3 UN的电老化寿命的不同下限值,对以电老化为主要老化因子的水冷定子线圈F级绝缘寿命进行了研究.结果表明:应用定子线圈F级绝缘寿命预测方法可以在设计、制造和运行阶段定量预测和评定汽轮发电机定子线圈F级绝缘寿命.     

空冷汽轮发电机转子通风冷却系统的结构优化

以125 MW空冷汽轮发电机转子为研究对象,建立了转子径向通风系统的冷却介质流量分配离散模型,并应用该模型对125 MW空冷汽轮发电机转子径向通风系统进行了结构优化,分析了副槽结构、转子槽楔出风口面积对转子径向风道流量分配的影响.结果表明:在相同入口流量下,副槽截面积越大,径向风道流量偏差越小;转子槽楔出风口面积越小,径向风道流量偏差越小;采用变转子副槽结构及变转子槽楔出风口面积均可使径向风道流量偏差减小.     

双层叠绕组发电机单元件横差保护特性分析

通过1号机横差保护动作的现象,对故障进行分析,得出测量双星形中性点电流作为双层叠绕组发电机单元件横差保护的,横差动作的原因可能是定子绕组匝间发生短路,也可能是转子匝间短路或者转子偏心引起磁场不均匀也会引起的结论,该结论对现场维护人员有一定得指导意义。     

A lightweight low‐speed permanent magnet electrical generator for direct‐drive wind turbines

The evolution, design and test results of a novel permanent magnet generator for use in direct‐drive wind turbines are presented. This generator topology is based on steel C‐core modules (which make up the rotor) and an air‐cored stator winding. This topology allows a reduction in structural mass for large diameter generators, which can lead to lightweight generators. Copyright © 2009 John Wiley & Sons, Ltd.     

A new energy recovery double winding cage-rotor induction machine

This paper proposes a new double winding induction machine and its speed control methods. The machine consists of two stator windings and one cage rotor. One stator acts as a motor and the other as a generator. By controlling the voltage supplied to the secondary or the generator winding, the rotor speed can be adjusted. The machine has a similar speed control characteristic to that of a slip-ring induction motor equipped with the rotor energy recovery scheme. The construction, principle, equivalent circuit, and speed control schemes of the new machine are presented. The performance characteristics of the machine are analyzed using the equivalent circuit and verified by experimental results.     

Performance evaluations of 50 MVA airgap winding stator forsuperconducting generator

Structural features of a trial-manufactured air-gap winding stator for a 50 MVA superconducting generator and results of various characteristic tests are described. The stator has an improved winding section, strengthened against electromagnetic force and smaller due to use of a four-layer water-cooled helical air-gap armature winding. The axial flux through the stator core, assumed to be generated by the circumferential current of the helical winding, is too low to pose any practical problems, as shown by a three-dimensional magnetic-field analysis taking into account the magnetic anisotropy due to the laminated iron core. The air-gap armature winding electromagnetic force in the radial and axial directions (which does not contribute to the generator output) increases when the running power factor decreases. The helical winding is shown to be applicable to the armature winding of large superconducting generators     

核电站汽轮发电机在线监测系统应用分析

通过对田湾核电站TBB-1000型汽轮发电机装设的温度在线监测系统、定子绕组端部振动在线监测系统、发电机气体分析在线监测系统应用情况进行分析,对各种不同的在线监测方法进行了研究和比较,指出核电站汽轮发电机在线监测系统的装设应根据可靠性与经济性的需要,灵活选用不同方式的在线监测手段,从而保证大型汽轮发电机组的安全可靠运行。     

Finite-element simulation of a generator on load during and after athree-phase fault

A two-dimensional, time-stepped, finite-element technique for the simulation of the electrical and mechanical transient response of a turbine generator to system faults is presented. The stator winding is modeled directly in phase bands, rather than as an equivalent sinusoidal distribution, and rotor torque is calculated by the Maxwell stress tensor method. The method is validated by a comparison of calculated results with test data for the case of a sudden three-phase short-circuit applied to a generator operating at full load, followed by fault clearance and reconnection to the power system     

A brushless self-exciting three-phase synchronous generatorutilizing the 5th-space harmonic component of magneto motive forcethrough armature currents

A novel brushless self-exciting three-phase synchronous generator is proposed. It consists of three-phase armature windings on the stator, one field winding and one exciting winding with five times as many poles as that of the armature winding on the rotor, and a three-phase reactor connected to the terminal of the armature windings. By utilizing the 5th-space harmonic component of armature electromotive force, small voltage regulation for various loads and no oscillatory tension occurring at the rotor shaft were realized. The basic constitution, principle of operations, and exciting characteristics are described. The experimental results obtained from using a trial generator demonstrated its practical usefulness     

大型变速恒频风力发电机组建模与仿真

基于SIMULND技术,利用双馈感应发电机、风力机、电压型变流器、电压型逆变器的数学模型建立了相应的仿真模型;并对定子侧直接与50Hz电网连接,转子侧连接AC/DC/AC变流器的典型变速恒频风力发电系统进行了仿真验证.几个单独的风力发电系统子系统可以通过级联的方式构成大型风力发电场来模拟整个电网的运行情况.仿真结果表明,DFIG仿真模型的正确性和验证大型风电场的有效性.     

基于直接负载法的某水轮发电机温升试验分析

鉴于定子及转子的温升指标是水轮发电机的重要运行参数之一,采用直接负荷法对某80 MW水轮发电机进行了温升试验,因当前试验水头低机组达不到额定负荷,计算并校正了当前最大负荷工况下发电机的定子绕阻、定子铁心及转子绕阻的温升情况,并对额定负荷工况下的各部温升进行了推算,计算和推算值均满足设计要求。该研究为水轮发电机安全运行提供了技术数据。     

Dynamic study of an electronically brushless DC machine viacomputer simulations

The authors analyze a machine with a conventional DC armature winding on the stator which does not have a field winding connected with slip rings. At positions where the winding would have been attached to a commutator segment, a transistor switch is attached instead. The rotor contains a permanent magnet field. The lap wound stator winding is sequentially commutated by a system consisting of a position sensor and logic circuitry. Analytical expressions for a full pitch lap wound machine are given. A computer simulation of the machine was implemented. The results serve to illustrate the considerations which must be made in the design of this type of machine, in particular the effects of the winding design on commutation and cost efficiency