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.     

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.      

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。     

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.     

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。     

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     

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。     

Integration of an Energy Capacitor System With a Variable-Speed Wind Generator

This paper presents a system using an energy capacitor system (ECS) to smoothen the output power fluctuation of a variable-speed wind farm. The variable-speed wind turbine driving a permanent-magnet synchronous generator is considered to be connected to the ac network through a fully controlled frequency converter. The detailed modeling and control strategy of the frequency converter as well as variable-speed operation of a wind turbine generator system are demonstrated. Afterward, a suitable and economical topology of ECS composed of a current-controlled voltage-source inverter, dc–dc buck/boost converter, and an electric double layer capacitor (EDLC) bank is presented, including their control strategies. Exponential moving average is used to generate the real input power reference of ECS. Another novel feature of this paper is the incorporation of a fuzzy-logic-controlled reference signal adjuster in the control of the dc–dc buck/boost converter, in which the stored energy of the EDLC bank is utilized in an efficient way. Due to this controller, the energy storage capacity of the EDLC bank can be reduced in size, thus resulting in reduction of the overall cost of the ECS unit as well as decrease in irrepressible operations during high and low energy levels of the EDLC bank. Finally, extensive simulation results are presented that validate the effectiveness of the proposed system to smoothen the output power fluctuation of the variable-speed wind farm.      

汽轮机、发电机转子轴颈现场修复方法

汽轮机、发电机转子轴颈运行后因各种原因轴颈磨损形成沟槽,影响机组安全运行,因转子庞大、电厂检修周期紧张等原因提出现场修复的要求,寻求安全可靠、经济的修复方法势在必行,文章分析了各种修复方法,提出微弧等离子现场修复方法,通过分析,有着很好的应用前景。     

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     

Experimental Study of Parameters Affecting the Nusselt Number of Generator Rotor and Stator

In this research, the parameters affecting the Nusselt number of a generator rotor and stator under varying heat transfer rate are experimentally studied. In spite of the stator having no grooves, the rotor has four large triangular grooves. The temperature and then heat transfer rate of the rotor and stator are experimentally measured in three longitudinal and two angular positions. First, the effect of axial Reynolds number and rotor rotational speed on the rotor and stator Nusselt number with constant heat transfer rate ratio is studied. The range of the axial Reynolds number and rotational speed used is from 4000 to 30,000 and from 300 to 1500 rpm, respectively. Next, the effect of stator to rotor heat transfer rate ratio on the Nusselt number at constant axial Reynolds number and rotational speed is investigated. Three experiments were conducted at three heat transfer rate ratios (3, 5, and 8), defined as the ratio of heat transfer rate of the stator to the rotor. The results show that the higher the heat transfer rate ratio, the lower is the stator mean Nusselt number and the higher the rotor mean Nusselt number.     

两级热电热机的有限时间热力学分析

建立了考虑外部传热影响的两级半导体热电热机模型,用有限时间热力学对牛顿传热规律下两级半导体热电热机的性能进行分析,导出了功率、效率与工作电流的一般关系式,得到了两侧换热器的最优面积分配和热电单元数的最优分配,并分析了多种因素对其性能的影响。     

上海引进型300MW机组发电机-励磁机振动特性综述

上海引进型300MW机组存在工作转速下励磁机振动不稳定问题.首次改进后引起临界转速区域发电机与励磁机振动响应过高问题.第二次改进后采用静态励磁方式,彻底解决了因设计原因引起的该型机组发电机-励磁机振动问题.基于现场实测数据及转子动力学理论,讨论及总结该型机组发电机-励磁机振动机理和特性.     

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.