超大型轴流转桨式水轮发电机组定子组装工艺

安谷水电站机组是超大型轴流转桨式水轮发电机组,定子机座散装运输到场,机座安装采用现场焊接方式。为克服机座尺寸大、质量重、当地温差大等定子安装精度的不利影响,介绍了定子机座焊接组装、定位筋安装调整、铁芯叠片和铁损试验等关键工序,并通过分析机组定子安装工艺和实践总结,优化了施工工序。实践证明定子组装质量得到严格控制,各项控制指标均满足规范标准,其安装工艺对同类型机组定子安装具有指导意义。     

超大型轴流转桨式水轮发电机组定子组装工艺

安谷水电站机组是超大型轴流转桨式水轮发电机组,定子机座散装运输到场,机座安装采用现场焊接方式。为克服机座尺寸大、质量重、当地温差大等定子安装精度的不利影响,介绍了定子机座焊接组装、定位筋安装调整、铁芯叠片和铁损试验等关键工序,并通过分析机组定子安装工艺和实践总结,优化了施工工序。实践证明定子组装质量得到严格控制,各项控制指标均满足规范标准,其安装工艺对同类型机组定子安装具有指导意义。     

某型起动机定子模态分析

起动机是装甲车发动机重要工作部件之一,其工作的稳定性和可靠性直接决定装甲车辆能否正常运行。为了避免起动机在运行过程中因外部激励与定子发生共振引起较大破坏,在建立定子三维有限元模型基础上,考虑无机座固定和有机座固定2种不同方式对固有频率的影响,基于ANSYS有限元分析软件对起动机定子进行了模态分析,得到了定子振动系统的固有频率和模态振型,结果表明该起动机定子结构设计合理。此外,还分析了机座螺栓连接对起动机定子模态频率的影响,找出了影响规律,提出了避免共振的措施,为降低起动机的振动提供依据。     

大型蒸发冷却发电机定子绕组绝缘电阻测试及分析

本文结合发电机定子绕组蒸发冷却系统组成,提出了不接屏蔽端和接屏蔽端两种测量发电机定子绕组绝缘电阻测量方法,并对定子绕组绝缘电阻测量值偏低进行分析处理,通过不同测试条件下的对比试验,发电机定子绕组在充液状态时,采用接屏蔽端方式能够准确测量定子绕组绝缘电阻。     

计及RSC控制的DFIG短路电流直流分量解析表达

现有文献针对计及转子变流器(RSC)控制的双馈感应风电机组(DFIG)定子短路电流解析表达,将定子磁链当作一阶直流衰减分量或忽略功率外环控制。基于DFIG电压、磁链和RSC控制方程,得到定子电流关于定子电压和定子功率的传递函数,提出定子电流的精确解析表达式。基于RSC内、外环PI参数关系,推导直流分量衰减时间常数和角频率关于PI参数的表达式。分析了RSC内外环PI参数对定子电流直流衰减分量的影响。仿真结果验证了解析表达式的准确性,为PI参数选取和保护装置测量、整定提供依据。     

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.     

600MW超临界机组发电机定子绕组的化学清洗

针对超临界机组发电机定子线圈温度异常问题,采用“5M1E”原则对发电机定子线圈温度异常成因进行了分析,提出了碱洗十酸洗十漂洗钝化的复合清洗工艺.经过化学清洗,发电机定子线棒的进水和出水差压明显下降,定子绕组局部超温现象消失,确保了机组安全和满负荷运行.     

大型机组定子接地保护的动作行为分析

分析和比较了大型机组各种中性点接地方式,阐述了定子经电阻接地时电阻必须满足的条件,以上海昊泾第二电厂为实例进行了验证.根据基波零序电压定子接地保护和三次谐波定子接地保护原理,以GE公司的DGP保护为例具体分析.针对大型机组100%定子接地保护灵敏度差的问题进行了讨论,提出了采用GE公司的D3P保护解决方案.吴泾第二电厂实验表明,在负荷较大时该方案能明显提高定子接地保护的灵敏度.     

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。     

基于任意时刻电网故障下的双馈风力发电机定子磁链全响应研究

为研究双馈风力发电机(DFIG)定子磁链的全响应与电网故障发生时刻的关系,通过求解DFIG状态方程,得到任意时刻故障下DFIG定子磁链的解析表达式;利用坐标分解方式研究了定子磁链稳态响应与故障时刻的关系;通过分析定子磁链直流分量的大小,研究了定子磁链自由响应与故障时刻的关系。结果表明,定子磁链稳态响应与故障时刻无关,且其大小随故障时刻的变化呈现2倍工频周期的变化规律。最后通过搭建Matlab/Simulink模型仿真验证了推导公式的准确性和理论分析的正确性,为DFIG低电压穿越时转子侧的控制策略提供了一定的理论依据。     

导叶约化中心位置对涡轮非定常气动计算的影响

针对工程上常用的基于叶片数约化的涡轮非定常计算方法,为了掌握导叶约化中心位置对于涡轮内部流动非定常计算结果的影响规律,对导叶前缘约化、导叶尾缘约化、不约化三个算例进行了非定常计算与对比分析.研究结果表明:导叶前缘约化方式对于涡轮气动性能时均值影响量级在1％以上,而导叶尾缘约化方式的影响不到前者的1/2;两种约化方式均能...     

透平叶片弯、扭、掠联合造型规律及其气动性能研究

为研究静叶弯、扭、掠联合造型对流场结构的影响,以某高压透平首级叶片为研究对象,借助计算流体力学与正交优化方法,基于动静叶最佳匹配原则（即对于每种静叶构型,动叶都进行了相应的扭转规律变化,使得动静叶气动性能处于最佳匹配状态）,研究了静叶不同复合构型方式对流场结构的影响。结果表明：在合理的静叶弯曲规律下,静叶扭转改型对透平性能有较大影响,掠改型对透平性能影响有限;在一定的扭转规律下,对静叶进行掠改型对轮周效率的影响较小,仅后掠改型会提高透平的轮周效率;对弯扭掠静叶匹配扭动叶进行联合优化,得到的最佳透平的轮周效率为87.12%,与原始透平相比,轮周效率提高了2.09%。     

大转折角涡轮静叶栅二次流的数值模拟

对大转折角涡轮静叶栅三维流动进行了数值模拟,并详细分析了叶栅沿流向各截面二次流及叶栅的气动特性.结果表明:由压力面向吸力面运动的二次流强度沿流向逐渐增大,引起吸力面附近的端壁附面层不断壮大且在后部卷起,并导致沿叶高总压损失系数和沿叶高出口气流角的剧烈变化.通过对不同高度的叶栅进行比较发现,叶高的减小会扩大二次流所占叶高区域,从而导致叶栅的二次流损失急剧增加.     

Aerodynamic analysis of a stator‐augmented linear cascade wind turbine

This study proposes to attach stator vanes to PowerWindow, a linear cascade wind turbine, to improve the flow direction in the device. By controlling the angle of attack, the stator vanes increase the acting force and decrease the undesirable force on PowerWindow blades. An analytical model using blade element momentum theory is developed for the new configuration, referred to as stator‐augmented PowerWindow. The analytical model has been verified by a computational fluid dynamic simulation. This study shows that the stator vanes are able to minimize/neutralize the undesirable axial force on PowerWindow so that the thrust coefficient decreases from 0.035 in the original model to ?0.005 in the stator‐augmented one. In addition, by increasing the acting force on the blades, the stator augmentation will simultaneously enhance the coefficient of performance by up to 10%. This study also shows that by using stator vanes to control the angle of attack, unlike in the original PowerWindow, the direction of rotation of the stator‐augmented PowerWindow will remain the same regardless of the wind direction, increasing the utility of the device in practice.     

Effect of Coils on Natural Frequencies of Stator Cores in Small Induction Motors

The electromagnetic noise of a motor is offensive to the ear. Most electromagnetic acoustic noises are generated when natural frequencies of a stator core coincide with or closely parallel frequencies of the magnetomotive forces. Therefore, to minimize such noise, an accurate estimate on natural frequencies of the stator is necessary. In this paper, the stator of a small induction motor is studied as to various factors such as the stator core shape, including a circumferential cut, and stiffness of varnished random winding in stator slots. Furthermore, the effect of coil ends on natural frequencies of the stator core is newly clarified. As a result, in the 2.2kW motor, an equivalent Young's modulus as stiffness of windings in the slots is obtained as being about 1/100th that of copper. Also, study clarifies that coupling vibration arises from the coil end and the stator core. It is found that this coupling vibration can be estimated briefly from a two free degree system.     

Numerical simulation of clocking effect on blade unsteady aerodynamic force in axial turbine

To give an insight into the clocking effect and its influence on the wake transportation and its interaction, the unsteady three-dimensional flow through a 1.5-stage axial low pressure turbine is simulated numerically by using a density-correction based, Reynolds-Averaged Navier-Stokes equations commercial CFD code. The 2nd stator clocking is applied over ten equal tangential positions. The results show that the harmonic blade number ratio is an important factor affecting the clocking effect. The clocking effect has very small influence on the turbine efficiency in this investigation. The difference between the maximum and minimum efficiency is about 0.1%. The maximum efficiency can be achieved when the 1st stator wake enters the 2nd stator passage near blade suction surface and its adjacent wake passes through the 2nd stator passage close to blade pressure surface. The minimum efficiency appears if the 1st stator wake impinges upon the leading edge of the 2nd stator and its adjacent wake of the 1st stator passes through the mid-channel in the 2nd stator. The wake convective transportation and the blade circulation variation due to its impingement on the subsequent blade are the main mechanism affecting the pressure variation in blade surface.     

高压共轨燃油系统涡旋叠片高速电磁铁的研制

介绍了一种新的柴油机高压共轨喷油系统高速电磁铁铁芯 ,新铁芯由许多厚度相等的涡旋形铁片堆叠而成。构成铁芯的方法之一是采用渐开线直纹面作为涡旋形铁片的理论曲面。铁片与铁片之间无间隙 ,电磁铁线圈安放在铁芯的沟槽内。它比常见的E形叠片电磁铁铁芯结构紧凑 ,性能更好。试验结果表明 ,新的电磁铁铁芯能满足ECD -U2高压共轨喷油系统的要求     

Stator Frame Deformation Problem in Large Diameter Hydro-Generators

The hydrogenerators which have been delivered to Peace Canyon Power Station of B.C. Hydro and Power Authority are large diameter machines. In large diameter hydrogenerators the relative displacement between the rotor and stator tends to increase, and in the worst case the rotor may touch the stator. The above hydrogenerators have experienced some problems due to the deformation of the stator frame. The outline of problems and investigations performed to determine the relationship between stator deformation and split phase current is presented.