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《中国电机工程学报》2016,(18)
该文分析了研究机组驱动点阻抗的自然谐振频率和该频率的驱动点电阻对次同步扭振模态电气负阻尼的影响,提出这2个参数是主导次同步扭振模态电气负阻尼的关键参数,定义了这2个参数关于电网元件阻抗参数的灵敏度指标。在这2个灵敏指标的基础上,提出一种识别实际系统次同步谐振"研究区域"边界节点的定量方法。最后,文中应用新英格兰的10台机39节点和IEEE FBM次同步谐振计算标准模型改编了一个算例,应用该仿真算例从频域和时域分别验证了上述建模方法的有效性。 相似文献
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为了解决风电机组中的次同步振荡(SSO)问题,针对双馈风力发电机组经串连补偿并网发生的次同步扭振(SSTI)问题展开了分析。首先简要介绍了双馈风机(DFIG)中发生SSTI形成的原因。推导建立了DFIG各个部分的小信号分析模型方程,联立方程形成全系统线性化方程。然后通过模态分析得到了SSTI的特征值,并计算出SSTI的相关因子,进而讨论了SSTI与转子侧参数、次同步扭振与风速的关系。通过模态阻尼比与MATLAB/SIMULINK时域仿真分析SSTI问题,验证了风速是否为影响SSTI的因素。 相似文献
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特征结构分析及在电力系统次同步谐振研究中的应用 总被引:4,自引:1,他引:4
引入参与矩阵的概念,对一带串联电容补偿的简单电力系统进行特征结构分析,解释了电力 系统稳定器(PSS)对系统低频振荡模态的抑制作用和它对轴系其他次同步扭振模态的危害及 其原因,为建立研究次同步谐振和轴系扭振的模型提供了理论依据,并引入响应比的概念分 析了电气量和轴系机械量的动态响应,揭示了次同步谐振和轴系扭振的内在联系。 相似文献
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考虑综合负荷动态模型的小干扰电压稳定研究 总被引:1,自引:0,他引:1
构建了简单电力系统考虑综合负荷感应电动机并联恒阻抗动态模型的电压稳定分析的微分代数方程组(DAE)模型.推导出系统线性化小干扰方程状态矩阵的解析表达式.对PV曲线上一些平衡点进行小干扰分析的结果表明系统静态传输功率极限点并不是系统的小干扰电压稳定极限点.分析了PV曲线上小干扰电压稳定极限点的位置与综合负荷模型参数变化的关系,结果表明其位置与参数kd、r2和s0的值有很大关系,实际系统的综合负荷参数处于kd很大、或r2很小、或s0很大的运行工况时将比较容易发生电压失稳. 相似文献
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考虑负荷动态模型的在线小干扰电压稳定指标 总被引:2,自引:1,他引:1
对电力系统在任一时间断面上从某个负荷母线向系统侧看进去的部分进行戴维南等值,并对负荷采用三阶感应电动机并联恒阻抗动态模型,分析该负荷节点的小干扰电压稳定性。通过对负荷节点PV曲线上的平衡点进行小干扰分析的结果表明,等值系统的小干扰电压稳定性本质上是负荷中感应电动机部分的静态稳定性,感应电动机部分采用三阶模型和一阶模型得到系统平衡点的小干扰电压稳定性是一致的,因而文中采用一阶模型条件下所推导出的系统在线小干扰电压稳定状态指标的解析表达式,能表征系统当前运行点各个负荷节点的电压稳定程度。IEEE39节点系统的计算结果表明该指标正确、有效、计算简便。 相似文献
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上都电厂SEDC提高次同步扭振阻尼的现场试验 总被引:4,自引:3,他引:1
在上都电厂4号机上进行了附加励磁阻尼控制(SEDC)提高次同步扭振阻尼的现场试验,介绍了试验的基本原理、运行环境、主要内容和试验数据分析。试验结果表明:采用励磁注入法可安全、可靠地激发轴系次同步扭振并精确测定其特征频率,SEDC能有效改善各扭振模态的阻尼且不会对励磁系统常规调节功能(自动电压调节器/电力系统稳定器)造成不利影响。作为中国第1次以现场试验方式实证SEDC提高次同步扭振模态阻尼的效果,为自主研发和应用SEDC抑制次同步振荡/谐振奠定了基础。 相似文献
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This paper describes an investigation into the dynamic behaviour of a power system containing synchronous generators, induction motors and series capacitors. Eigenvalue techniques are applied to the linearized system equations to determine the small-signal stability properties prior to the application of a number of severe faults to different network configurations. Fourier transforms of the transient results are used to assess the effects of network series capacitors, induction motor loads and of the cross-coupling between generators. The results show that under certain conditions the correct modelling of the induction motor not only affects the network's electrical resonant frequency, but also introduces an extra resonance which may not have been predicted by the simpler motor models. 相似文献
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双馈感应发电机的线性化动态模型及运行特性分析 总被引:2,自引:2,他引:0
对建立在定子旋转磁场坐标系中,以转子绕组励磁电压为控制变量的双馈感应发电机的3阶动态模型进行了线性化处理,得到了适用于小干扰稳定分析的双馈感应发电机状态方程和相应的传递函数.进而利用开环传递函数和根轨迹方法分析了发电机运行点与发电机动态品质的关系,并利用MATLAB软件对双馈感应发电机的控制变量在发生幅值不同的扰动变化时的动态响应做了对比仿真.该仿真分析将有利于了解双馈感应发电机的运行特性及掌握它的控制特性.文中提出的双馈感应发电机线性化模型适用于变速恒频双馈风力发电系统的相关研究. 相似文献
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A self-excited wound-rotor induction generator excited with a capacitor can be used as an independent source for small-capacity wind power generator. With constant excitation capacitance, the secondary-circuit power of the induction generator is returned to the primary circuit through a converter, an inverter and a transformer; the power is controlled at the inverter so that the generator voltage is always maintained constant in spite of the changes of generator speed and load. The basic characteristics of the generator under the above conditions are analyzed. The fundamental waves of both the main circuit and the feedback circuit are determined. Using these results, the equations for various portions of the generator are derived, the performance characteristics of the generator are then analyzed and compared with experimental results. 相似文献
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This paper is motivated to analyze the transient behavior of a single-phase self-excited induction generator (SEIG) using a three-phase machine due to switching of single-phase dynamic load like induction motors. The generator consists of a three-phase star connected induction machine excited with three-capacitors and a single-phase induction motor (IM) load. The developed dynamic models of the SEIG and the motor are based on stationary reference frame d–q axes theory incorporating the effect of cross-saturation in the magnetic circuit of the machine and the equations of excitation capacitors are described by three-phase abc model. The system suffers from heavy transients during switching of induction motor and becomes unstable. These problems may be due to resonance caused by series capacitors and the inductive motor load. The use of damping resistors across one series capacitor is proposed to damp out the starting transients for the stable operation. The motor can be started up successfully using the damping resistor. The variation of the damping resistance with the increase in load on the motor after successful starting to maintain constant terminal voltage has been presented. The eigenvalue technique is also employed to examine the transient conditions in the studied SEIG-IM system. The simulated and experimental results are presented for both the unsuccessful and successful starting of the motor. These results are in close agreement with each other, which show the effectiveness of the approach. 相似文献
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鉴于机端电容大小对异步发电机端电压的影响,为保证异步发电机稳压运行,提出了一种计算电容值的方法。把异步发电机稳态运行作为暂态运行的特殊情况考虑,根据任意速旋转坐标系统下异步发电机的暂态模型,推导了稳态运行时相应的矩阵方程。令发电机稳态运行所对应齐次方程的行列式为零,并使发电机的端电压为恒值,计算不同运行状况下机端电容值。以发电机端电压保持恒值为约束条件,用直接搜索优化方法求解目标函数,此法克服了传统的迭代解法稳定性差与难于处理有约束条件之缺点。论文给出了异步发电机在不同负载下稳压所需的机端电容值,计算结果与实验结果的相互吻合说明了分析方法的有效性与准确性。 相似文献
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V. R. STEFANOVIC 《电力部件与系统》2013,41(3):255-266
ABSTRACT Characteristics of a closed loop induction motor drive, supplied from a variable frequency voltage source, and operating under constant volts/hertz control are presented. The motor linearized equations in the synchronously rotating reference frame are used to analyse the drive dynamic performance. It is shown that this performance can be greatly improved by including a properly designed speed controller in the drive structure. Thus, the decrease in stability, associated with the open loop motor operation is eliminated and the resulting drive gives satisfactory performance over the entire input frequency range. The experimental results, which confirm the validity of the motor dynamic model are also included. 相似文献
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This paper presents a detailed modeling and a comprehensive assessment of small-signal stability for a “more-electric” vehicular power system consisting of a synchronous variable-frequency generator which supplies power electronic controlled loads via an 18-pulse autotransformer rectifier unit for AC-DC conversion. Functional models for key power system components and loads are derived. Analytical derivations employed for small signal stability analysis based on linearized equations are described, and the influence of leading design parameters on system stability is evaluated. 相似文献
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同步电机异步-同步起动过程分析 总被引:4,自引:2,他引:4
根据同步电机异步-同步起动的实际过程,详细推导了异步-同步起动的双机耦合数学模型,利用派克方程建立了分析同步电机半同步起动过程的状态方程。在此基础上,对影响电机起动成功与否的几个重要因素,如:发电机的初始速度、外加驱动转矩、发电机和电动机的励磁电流以及连接线路阻抗等进行了详细分析,并给出了起动过程中发电机和电动机的转速以及转矩的变化规律。仿真分析与实验结果吻合较好。 相似文献
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基于变结构控制的变速恒频双馈风力发电机并网控制 总被引:3,自引:3,他引:0
将矢量控制技术、逆系统方法、变结构控制技术相结合,提出了一种新的变速恒频双馈风力发电机空载并网控制策略.双馈异步发电机的数学模型在m一t坐标系下是一个非线性耦合系统.采用逆系统方法将转子电压方程线性化解耦,构造出伪线性系统;然后,设计伪线性系统的变结构控制律;利用Matlab软件搭建了变速恒频双馈风力发电系统的仿真模型,进行仿真分析.仿真结果表明,所采用的控制策略能够完成发电机平滑接入电网,并网运行效果理想,实现了定予输出有功与无功功率的独立调节.与PI控制方案相比,变结构控制方案具有更好的动态响应性能. 相似文献