大型汽轮发电机壳体异常振动诊断及治理方法研究

针对大型汽轮发电机组发电机定子壳体振动超标和非稳态振动问题,提出了一种基于发电机壳体结构共振的故障识别及综合治理方法,并以某300 MW和某630 MW机组为例进行了验证。结果表明：发电机定子底部载荷分布不均诱发的连接刚度下降和发电机转子的热不平衡是导致发电机定子局部共振或振动超标的主要原因,采取载荷均布调整、现场动平衡等措施,可消除此类故障。     

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。     

水冷壁折焰角的吊装

本文根据锅炉水冷壁折焰角和后水冷壁垂直段管屏的结构、重量、位置以及吊装能力,制定了水冷壁折焰角组件的吊装组合方案,详细介绍了受热面的吊点布置情况,并通过精确计算确定了卷扬机钢丝绳的型号.本文重点介绍了折焰角组件吊装前的准备工作,详尽介绍的整个起吊过程.     

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。     

刘家峡2~#发电机定子线棒采用313°不完全换位

刘家峡2~# 发电机系1969年产品,定子线棒采用 0°/360°/0°换位方式,主绝缘为环氧粉云母带B级绝缘.这种换位方式使定子线棒的股线、电流及温度分布很不均匀,导致线棒的平均温度升高,局部温度更高,严重影响线棒运行的可靠性和使用寿命.为解决此问题,并结合发电机改造增容(由225MW增至250MW),决定线棒采用新的换位方式.     

谐振补偿在大型发电机中性点接地中的应用

详细分析了发电机中性点经消弧线圈谐振补偿接地方式的应用原理,提出一种发电机中性点接地方式,并且与中性点经接地变压器高电阻接地方式进行比较。这种中性点接地方式可以更好地限制定子单相接地时的故障电流,从而保护了定子铁心和绕组。采用多回路分析方法对三峡左岸一种700 MW的大型发电机进行仿真计算,仿真结果表明此方法是可行的。     

变速抽水蓄能发电电动机电磁设计与试验研究

根据变速抽水蓄能发电电动机的运行原理、等效电路以及功率传输特性,对10MW变速抽水蓄能发电电动机进行了电磁设计,确定了10MW变速抽水蓄能发电电动机的主要结构尺寸;建立了变速抽水蓄能发电电动机二维电磁场的数学方程和物理模型,对变速抽水蓄能发电电动机电磁场数学方程进行了计算,分析了变速抽水蓄能电机在发电机工况下亚同步速时磁力线和气隙磁密的分布情况,确定了在发电机工况下亚同步速时定子电压波形和定子电流波形,研究了定子铁芯损耗和转子铁芯损耗的分布规律;根据电磁设计参数加工制造了10MW变速抽水蓄能发电电动机样机,搭建试验测试平台,将试验测试结果和计算结果进行对比,验证了电磁设计方案的可行性和计算结果的准确性,为更大容量变速抽水蓄能电机的研究奠定了基础.     

660MW级双水内冷汽轮发电机水系统的研发和验证

双水内冷汽轮发电机技术是我国首创并具有完全自主知识产权的技术.在分析双水内冷汽轮发电机水系统运行中存在的主要问题的基础上,研发了660 MW级双水内冷汽轮发电机水系统,简述了660MW级双水内冷汽轮发电机水系统的技术规范、设计原则、组成,分析了660MW级双水内冷汽轮发电机水系统特点.型式试验结果表明,所研发的660MW级双水内冷汽轮发电机水系统的性能达到了设计要求,能保证660 MW级双水内冷汽轮发电机的安全可靠运行,为660 MW级双水内冷汽轮发电机的研制和投运奠定了基础.     

大型水氢氢汽轮发电机通风系统特点及性能分析

目前功率在600 MW及以上的大型汽轮发电机多采用水氢氢冷却方式,即定子线圈采用水冷,定子铁芯及转子线圈采用氢冷.通过将采用不同通风型式的定子铁芯及转子线圈进行组合,可派生出多种通风系统,但是不同通风系统之间的性能尚无法用统一的数学模型进行量化.在对水氢氢汽轮发电机不同通风系统进行分析、比较的基础上,提出了通风系统效率(EVS)的概念,并给出相应的计算方法,可对不同通风系统的性能进行比较,也可为通风系统的选择提供一定的参考依据.     

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.     

A new approach to determine transient generator winding and dampercurrents in case of internal and external faults and abnormal operation.III. Results

For pt.II see IEEE Winter Meeting, New Orleans, LA, 1986. A novel method for analyzing the steady-state and transient currents in the stator, rotor, and damper windings of a large generator is discussed, and the application of the method to five classes of problems of practical importance is described. These are (1) internal phase-to-phase fault in a two-circuit machine; (2) 180° out-of-phase synchronization; (3) three-phase short circuit at generator terminals; (4) clearing of a three-phase system fault; and (5) unbalanced steady-state negative phase sequence load of 6%. The authors show the individual damper bar currents and energies or electric power loadings for these cases and, for one example, the time variations of stator and damper winding currents. The investigation was conducted on a standard two-pole generator that was designed for 60 Hz operation and has a rating of 700 MW     

Effects of toothless stator design on dynamic model parameters ofpermanent magnet generators

The effects of toothless stator design on the dynamic model parameters of permanent magnet (PM) generators are presented. These parameters, which include inductances and induced back EMFs, are determined for a 75 kVA, 208 V, 400 Hz, two-pole, permanent magnet generator. Two particular stator designs, a toothless stator, and a conventional type stator (with iron teeth), are considered. The method which is used to determine these parameters is general in nature and is based on the use of a series of magnetic field solutions. A validation of the computed EMF and inductance values based on experimentally obtained data is given. The results of using these parameters in a state space model in the abc frame of reference to study the effects of a toothless stator design on the PM generator synchronous inductances are presented. Based on that, it is demonstrated that the effects of rotor saliency and armature loading on the machine parameters are minimized in the case of the toothless design     

多对极发电机励磁绕组匝间短路故障在线定位理论研究

大型水轮发电机和抽水蓄能发电电动机均为多对极,现场迫切希望实现故障磁极的在线定位.本文基于一台3对极、12kW的发电机动模样机研究在线定位的理论基础.首先,采用场路结合法对该样机在联网工况下的励磁绕组匝间短路故障进行了计算,并与实验结果进行了对比和分析,验证了计算模型的正确性.然后,利用故障数学模型对该样机一极短路故障...     

Electromagnetic design and optimization of dual‐stator brushless doubly‐fed wind power generator with cage‐barrier rotor

This paper explores the feasibility of an intuitive solution torque density for the existing brushless doubly‐fed generator by dual‐stator and cage‐barrier rotor structure, so as to better adapt to the offshore wind power generation. The torque density of electrical machine is related to the key design parameters, such as the machine main dimensions, slot‐pole combinations, coupling between stator and rotor, and nonmagnetic ring thickness. According to working principles and design requirements of electrical machine, the dual‐stator brushless doubly‐fed wind power generator (DSBDFWPG) with cage‐barrier rotor is designed, and the key parameters relating to torque density are analyzed and discussed. Meanwhile, the main parameters of electrical machine are optimized by Taguchi method, such as air‐gap length and nonmagnetic ring thickness. On this basis, the performance parameters of DSBDFWPG are analyzed by finite element method, which is verified by experimental tests. Through analysis of the results, not only the design requirements are satisfied by the DSBDFWPG, but also the correctness and rationality of machine design method can also be verified. Finally, the torque density and other aspects of designed DSBDFWPG are compared with dual‐stator brushless doubly‐fed induction generator, doubly‐fed induction generator, asynchronous machine, and brushless doubly‐fed generator; it demonstrates the torque density improvement of the studied machine with its significance and value.     

小型风力发电机电磁设计特点

文章分析了小型风电机组用的永磁同步发电机的电磁设计特点,并与其他普通永磁电机区别,详细介绍了永磁同步发电机各个电磁参数的特点以及对发电机性能的影响。重点介绍永磁同步发电机定子、转子设计的特点,对不同的极数与槽数的配合进行对比分析,总结降低齿槽转矩的规律。     

Peaked-MMF smooth-torque reluctance motors

The authors investigate the steady-state torque characteristics of reluctance motors with nonsalient stator punchings, but with peaked rotating magnetomotive forces (MMFs). The torque calculation includes the effects of saturation and fringing and groove fluxes. The peaked rotating MMF is produced by properly coordinated current waveforms and winding. Peaked-MMF reluctance motors have tow major advantages: the torque is smooth and the flux per pole required to produce a given torque is lower than that of conventional reluctance motors. This property is most beneficial to two-pole reluctance motors, for a given frame whose bore diameters and slot areas can be increased significantly for higher ratings or better performance. Unlike switched reluctance motors, shaft encoders are not required for peaked-MMF motors     

Study of a longitudinal flux permanent magnet linear generator for wave energy converters

A directly coupled linear permanent magnet generator of longitudinal flux‐type is investigated. The generator will be used for power take‐off in a wave energy converter. A combined field‐ and circuit model, solved by a time stepping finite element technique, is used to model and analyse the electromagnetic behaviour of the machine. A large number of simulations form the basis of a design study where the influence of armature current level, number of cables per slot, and pole width is investigated with respect to efficiency, generator size, and the load angle. A case study is performed for a chosen generator design. The electromagnetic behaviour is examined both for nominal load and for overloads. The generator has a nominal output power of 10 kW for a constant piston speed of 0.7 ms^?1. The electromagnetic efficiency at nominal load is 86.0%, the load angle 6.6°, and the power fluctuation 1.3%. At 300% overload the load angle barely exceeds 12° and the cable temperature is below 25°C provided that the stator back is thermally connected to the sea water. The numerical calculations have been verified for small speeds by experiments. Copyright © 2006 John Wiley & Sons, Ltd.     

那邦电站发电机主要部件有限元分析

为确保那邦电站高转速水轮发电机各主要部件结构的合理可靠性,采用CATIA三维设计软件对发电机定子机座、转子磁轭、磁极、上机架各主要核心受力部件建立几何模型,并用MSC.patran建立计算模型,根据发电机自身的受力特点确定各部件的工况及边界条件,运用有限元受力分析找出了各主要部件受力的薄弱点,使结构性能得以进一步优化。计算结果及实际运行情况表明,有限元计算给发电机各主要部件的结构设计及材料合理选用提供了很好的支持,保障了发电机长期安全稳定运行。