Steady-State Analysis of a Self-Excited Single-Phase Reluctance Generator

This paper presents an analytical method for predicting the steady-state performance of a self-excited single-phase reluctance generator (SESPRG), which supplies R-- L load. The proposed analysis is based on the d--q axis model and phasor diagram of such a generator in the steady-state condition. Excitation capacitors are connected across both the main and auxiliary windings. Magnetic saturation is taken into account and is assumed to be confined to the direct axis, and is accounted for a variable direct-axis magnetizing reactance. Conditions of self-excitation and the minimum value of the capacitance required to achieve self-excitation are also given. Special attention is focused on the machine performance when it operates as a pure single-phase reluctance generator (PSPRG). A fixed-capacitor (FC) thyristor-controlled reactor (TCR) scheme is used to regulate the generator terminal voltage by controlling the thyristor conduction angle. Further stability limits are investigated by developing the active-reactive (P-Q) power diagram. Reasonably close agreement between the measured and predicted results is observed confirming the validity of the proposed analysis.     

某型发电机转子故障分析

燃气轮机发电机作为调峰机组担负着电网调峰调频的重要作用。启停频繁、工况多变导致其运行条件相对较差,发电机转子特别是端部绕组作为高速旋转部件受力情况复杂,长期启停调峰使转子故障概率增大,甚至造成转子绕组开路导致发电机无法励磁,异常现象随转速变化呈现不稳定状态,故障排查难度较大。工程师在不同工况下进行试验验证,查找故障点,分析原因,转子返厂进行解体修复,提出改进措施,提高主设备运行可靠性。     

Saturation Modeling and Stability Analysis of Synchronous Reluctance Generator

A new method of representing magnetic saturation in synchronous reluctance generator has been proposed in this paper. A linearized model of synchronous reluctance generator has been developed applying the proposed saturation model to perform the steady-state stability analysis. The effect of $d$ - and $q$-axis saturation on the steady-state stability of a synchronous reluctance generator has been investigated using the proposed linearized machine model. Effects of different loading conditions such as active power, reactive power, and power factor on the steady-state stability have also been looked into. Moreover, the effect of $d$- and $q$-axis saturation on the transient stability analysis has been investigated in the case of a three-phase symmetrical ground fault at the machine terminals.      

燃气轮机转子裂纹故障分析与诊断

振动监测和诊断是及时诊断旋转机械故障的手段之一,其中的频谱分析能有效地诊断出转子裂纹。介绍了某燃气轮机转子裂纹的振动现象、处理过程以及故障诊断。转子裂纹的振动有以下特征:裂纹转子具有刚度不对称的特点,运行中存在二倍频振动,在启停机经过转子临界转速一半时存在二倍频共振峰;随着裂纹的发展,二倍频共振峰值有增大趋势;联轴器瓢偏以及低速盘车时转子晃度也会增大。根据转子的振动特征判断该转子存在裂纹且仍在发展,检查结果验证了故障诊断的正确性,为转子裂纹的故障分析与诊断提供参考。     

高均匀性稳态磁场发生装置的优化研究

目的  为了考核电力与电子设备的抗磁场干扰能力,需要进行相应的磁场抗扰度测试,其中高均匀性稳态磁场发生装置是稳态测试装置的核心部件。 方法  以常规Helmholtz和Maxwell方形线圈为研究对象,通过数值计算进行参数优化,解析得出能够产生高性能磁场的线圈结构,并使用有限元法建立模型进行计算,验证了结果的正确性。 结果  通过数值分析得出线圈参数的一般通用计算公式,并对比两种线圈型式,选择尺寸和功耗较小的优化型Maxwell方形线圈作为最终结构。 结论  为高均匀性稳态磁场发生装置提供了详细的计算过程和设计参考,可以给电气行业的相应设备设计提供理论依据。     

大长径比水轮发电机转子动平衡试验分析

为了消除水轮发电机组在运转中不平衡力的影响，减少机组的振动，采用3次启动法对大长径比水轮发电机进行动平衡试验，找出了失衡方位和失衡量的大小，然后加以配重，这是一种有效的消振方法。     

发电机转子顶起高度计算

分别从轴承的几何形状偏差、粗糙度、偏斜量及润滑时的膜厚比来分析计算出燃气轮机发电机组转 子需要被顶起的高度值。在项目安装调试时,将顶轴油系统压力提升至要求的范围内,并反复调试“机端”与 “励端”的油囊压力值与顶起的高度值,最终调试出合适的参数。     

Analysis of Operation of a Self-Excited Induction Generator With Generalized Impedance Controller

In this paper, analysis of the operation of a stand-alone self-excited induction generator (SEIG) with generalized impedance controller (GIC) (voltage source pulsewidth-modulated bidirectional inverter with dc link battery) has been discussed. Model of the SEIG along with the generalized impedance controller, has been developed in MATLAB/Simulink environment. The simulation results obtained for steady-state operation of the system, following speed and load perturbations have been presented here. The simulation results are validated with the experimental ones, which are conducted on a laboratory prototype of the SEIG-GIC system. The generalized impedance controller is found to be capable of maintaining the frequency of the SEIG constant under open-loop condition, following the speed and load perturbations.     

Starting the Single-Phase Switched Reluctance Motor Using Rotor Shorting Rings

This article presents a technique that uses rotor shorting rings to start the single-phase switched reluctance (SR) machine, from any rotor position, in a specified direction. It also outlines how the shorting rings enable starting of the machine. Transient finite-element analysis is used to illustrate the torque-producing mechanism from the aligned position using the rotor-mounted shorting rings. It is also used to determine the optimal stator and rotor pole arcs and shorting ring design for a 200-W prototype machine. An SR drive system incorporating rotor shorting rings is evaluated, and experimental results show the effectiveness of the technique     

9FA燃机发电机转子故障处理及分析

对发电机转子异响和接地故障实例进行分析,认为异响是由于一块绝缘塞块的固定片撕裂,造成绝缘塞块随转子低速旋转时在重力和向心力的共同作用下敲击护环所致;接地故障原因是由于内环极引线螺钉出现松动磨损,并产生大量含金属粉末覆盖在压帽以下的导电杆表面及转子本体绝缘层上。总结处理过程,供同类9FA电厂技术人员参考借鉴,便于对发电机转子故障情况的分析预判,制定最佳处理方案。     

汽轮发电机组轴系扭振特性计算分析

介绍了采用多段集中质量模型计算轴导振特性的两种方法：传递矩阵法及特征向量。并利用上述两方法对某电厂１号机轴系的扭振特性进行了计算分析。     

基于有限元法的水轮发电机转子偏心运行轴系模态分析

针对发电机质量偏心问题,分别探讨了偏心距离及导轴承刚度变化对机组振动特性的影响。首先对导轴承进行参数化处理,整机轴系建模后,通过FEM模态分析方法计算得到前10阶临界频率及振型的模态分析结果,进一步确定位移变形集中的危险点。然后对比不同约束条件下振型、临界频率、导轴承中心点振型轨迹,获得转子质量不对中造成的机组振动特性为因机组的转子偏心旋转造成轴瓦间隙逐步扩大,而机组振动信号中主频不变,计算结果与现场实际测量数据一致。     

洪江水电厂发电机转子支臂裂纹成因及处理方法

针对洪江水电厂发电机转子支臂焊缝裂纹问题,采用碳当量法计算了转子中心体、支臂筋板材质焊接性能参数,并结合转子支架有限元应力计算,综合分析了裂纹的成因,即主要是由于低碳合金钢焊接工艺控制不良,在应力集中处产生了疲劳裂纹。进而提出改进中心体和支臂焊接工艺的方法,包括改进预热和后热温度、增强焊缝尺寸、超声冲击消应处理等。通过对焊缝处理前、后裂纹情况的比较表明,新工艺有效地避免了裂纹产生。     

Model-Based Digital Generator Control Unit for a Variable Frequency Synchronous Generator With Brushless Exciter

This paper presents the design and implementation of a digital signal processor (DSP)-based generator control unit (GCU) for a variable frequency synchronous generator with brush-less exciter. A novel model-based control algorithm is proposed to better account for the wide operating frequency range and various load conditions. In addition to the model-based inner-loop exciter field current regulator and outer-loop generator voltage regulator, the control algorithm also adopts a generator-model-based d-axis current feed-forward loop to compensate for the load disturbance. Simulation and test results show a considerable performance improvement for the new controller when compared to the existing controllers, including better dynamics, better damping stability margin, and more uniform response over the operating range.     

基于DSP的发电机转子接地保护装置设计

针对发电机实际运行中常出现励磁回路接地故障,提出了一种基于微机(DSP)的发电机转子接地保护装置的设计方案.在研究发电机转子接地保护原理的基础上,给出并分析了硬件系统方案设计及转子接地检测系统软件设计,试验测试结果表明,该装置灵敏性、可靠性较高,现场运行效果良好.     

三峡右岸发电机转子磁轭组装

本文介绍了三峡右岸电站700MW巨型水轮发电机转子磁轭组装过程、工艺过程、质量要求。     

具SSS离合器的汽轮发电机组轴系动力特性分析

对某具SSS离合器的汽轮发电机组轴系的动力特性进行了深入的分析,给出优良的转子-轴承结构匹配设计方案,以确保该机组轴系具有良好的动力学性能,并确保机组安全投运。     

水内冷发电机内冷水流量不均匀时转子振动特征的计算与分析

应用计算温度场、应力场位移的有限元计算程序和不平衡响应程序,计算分析了水内冷汽轮发电机在冷却水流量不均匀情况下的转子振动特性,并总结出一套判别规则,可直接运用于现场机组振动的分析-故障诊断。图5表5参6     

变速恒频风力发电机转子机械故障模糊诊断方法

摘要： 针对当前方法在诊断变速恒频风力发电机转子机械故障过程中,抗干扰能力差、准确率低的不足,提出一种基于改进支持向量机（FSVM）与粒子群（PSO）加权模糊聚类相结合的转子机械故障模糊诊断方法。首先提取风力发电机转子机械故障的信号特征,对特征奇异点进行模极大值分析;构建FSVM诊断数学模型,完成信号特征的分类处理;基于PSO方法对分类处理后的特征信号,进行加权模糊聚类和个体寻优,实现发电机转子机械故障的模糊诊断。实验证明,提出的方法诊断精度高、收敛速度快、具有较高的实用性和可靠性。