大规模电力系统分解聚合法直接暂态稳定分析

本文旨在研究用分解聚合网络方程解法进行大规模电力系统的直接暂态稳定分析．分析中网络用分块矩阵表示，故障所在子块发电机采用Ｅｑ恒定模型，负荷计及电压特性．而非故障子块则发电机采用经典模型、负荷作线性简化．能量函数计算采用ＰＥＢＳ法，并沿故障轨迹积分，以简化暂态能量的计算．通过对华中５７机３５５节点互联电力系统的大量计算及研究，证明了本文方法的快速性与实用性．     

变压器涌流瞬态过程的软件模拟

励磁涌流发生在变压器投入运行的瞬态过程中，与合闸初相角、磁路中剩磁通、时间常数和线圈匝数等因素有关。对涌流瞬态过程进行了分析，研究计算方法并编制了计算软件，可以对变压器空载合闸时的励磁涌流进行计算模拟。     

自备电厂发电机励磁系统稳定性分析及控制研究

励磁系统的控制模式和控制参数对发电机及电力系统安全稳定运行有较大影响,一些厂矿企业电网的停电事故,暴露出自备电厂运行时存在励磁系统稳定问题。针对此问题,建立了计及恒无功、恒功率因数励磁控制方式的Heffron-Philips扩展模型,形成系统状态矩阵,通过特征根分析研究影响励磁系统稳定性的主要因素;基于根轨迹方法提出一种考虑系统稳定性的励磁系统控制参数优化方法。剖析了某实际厂矿企业自备电厂发电机组异常振荡现象的机理,并改进了励磁控制参数,仿真结果验证了所提方法的有效性。     

Transient stabilization of structure preserving power systems with excitation control via energy-shaping

In this paper, the transient stability of multimachine power systems based on structure preserving model (SPM) is considered. The interconnection and damping assignment passivity-based control (IDA-PBC) methodology is extended to solve the excitation regulation problem of SPM represented by a set of differential-algebraic equations. By shaping the total energy function via the introduction of a virtual coupling between the electrical and the mechanical dynamics of the power system, a decentralized excitation control law is proposed to ensure the asymptotic stability of the closed-loop system. The controller is proved to be effective in damping the oscillations and enhancing the system stability by the results of simulation research.     

Critical Generation Evaluation Using Hybrid Energy Function Method

It is well known that the transient energy function (TEF) method is useful for an efficient transient stability assessment as represented by the estimation of the critical clearing time (CCT). However, there still remains an issue for practical use: most of the TEF methods adopt the classical model of a synchronous machine in which the internally generated voltage is assumed to be constant. Moreover, critical generated output can be a more practical stability index instead of the CCT used in the conventional TEF methods. In this paper, a conventional hybrid TEF method is developed in order to estimate the transient stable critical generated power by using an improved hybrid simulation. The proposed method can handle the detailed model for a synchronous machine and can estimate the critical generated power with higher accuracy. Experimental results for a large network model are given in order to verify the practicability of the proposed method.     

同步风力发电机无刷励磁系统设计

提出了无刷励磁同步风力发电机励磁系统设计方案,采用可控硅静止励磁装置向交流励磁机定子励磁绕组提供直流电,励磁机发出交流电经过旋转整流器供给风力发电机励磁。只需跟随风速变化,控制励磁机的励磁从而可以控制同步发电机的励磁,使得输出电压恒定。在额定风速以下,获得最大风能利用系数,额定风速以上,保证输出功率恒定。并提出了基于单神经元自适应PID控制算法的控制器设计,该系统具有可靠性高、抗干扰能力强、硬件简单和系统可扩展性强的特点。     

Transient energy dissipation of resistances and its effect on power system damping

The transient energy flow method is a newly proposed method for locating the sources of low frequency oscillations and shows good performances in tests and actual applications. It is found in previous work that resistances in networks or loads may produce transient energy and exhibit as oscillation sources. In this paper, the transient energy dissipation of resistances and its effect on power system damping is studied. The transient energy flow into a resistance is generally non-conservative but whether it is dissipative is indefinite. A resistance may dissipate or produce transient energy. However, the relationship between system damping represented with the real-part of the eigenvalue and the total energy dissipation is definite, and an equation describing the relationship is obtained in simple power systems. Transient energy dissipation is an indicator of the damping of a component. When a resistance dissipates transient energy, it is beneficial to system damping, otherwise it is detrimental. The results are verified with simulations and explanations for constant impedance loads at different locations having different effects on damping are given.     

暂态能量函数的动力学机制

本文分析了全阶Ｐａｒｋ模型下同步发电机机电暂态能量转换机制，为暂态能量函数法成功地应用于详细模型下多机电力系统暂态稳定分析之中奠定了物理基础。同时也阐明了用参变量法构造暂态能量函数的局限性。     

交通牵引大功率单边直线感应电机性能研究

从单边直线感应电机(SLIM)气隙磁密方程入手,引入绕组函数方法,将次级绕组分为基波和边端效应波分量。根据初级绕组分布,推导出两相静止坐标下的初级绕组函数,解出次级绕组基波和边缘效应波分量。由绕组函数理论计算出电感、品质因数、次级电阻和运动电势系数,建立电压和磁链方程。根据初次级能量转换关系,得到推力方程。通过恒流恒频下的暂态特性和几种变频模式下的稳态特性计算,比较了实际稳态运行中的大功率SLIM的相电流、推力和效率的计算值和测量值。结果表明,绕组函数法能较好地描述边端效应,得到的稳态推力、效率和试验基本吻合,并证明了暂态计算的真实性。该模型可用于电机设计和特性分析中,具有一定的实用性。     

A comprehensive generator-line-infinite-bus micromachine model

For almost twenty years, a miniature three-phase electric power system has been used by students at the University of Manitoba, in several courses and for many student “hands on” projects. It features a realistic natural frequency of about one hertz, a realistic exciter/field time constant of about five seconds, a solid state exciter, many short time constant tranducers, a unique “synchroscope,” and a storage oscilloscope. On the storage oscilloscope power-versus-phase curves can be observed-something seldom seen by practising engineers or students in the usual laboratory situation. Advanced students can construct operational amplifier based stabilizers on a bread-board close to the regulator which is also on a small bread-board     

交流励磁电机实用性问题的探讨

交流励磁电机是20世纪末电机领域的一个革新课题。对交流励磁电机实施调频、调幅、调相等技术措施,可实现恒频变速运行的发电机或电动机功能、改善系统无功调节特性、提高系统稳定性和适应负荷快速变化的功能。但由于受到制造技术和成本的制约,其运用范围并不大,只有当其转子电流频率f1在-10Hz相似文献   

Phase-shifting transformers in a structure-preserving energy function

With some exceptions, direct methods have so far not been properly able to assess the transient stability of general power systems with phase-shifting transformers (PSTs) because there were no energy functions that would include their action in a post-fault situation. In this paper, we propose two additional potential-energy function parts for the two most common PSTs that can be added to any existing structure-preserving energy functions (SPEF). In this way, modularity is achieved and other FACTS devices can easily be taken into consideration. Using the proposed energy functions, it is possible to apply direct methods to any system that consists of an arbitrary number of phase-angle regulators (PAR) and quadrature-boosting transformers (QBT).These new energy functions assume a constant controllable parameter; however, we extended the use of the presented energy functions by a simple procedure that makes the direct method able to consider any parameter change in a post-fault system.The proposed energy-function extensions were tested in a longitudinal system, because only in such a system will direct methods and a simulation give the same results. Another demonstration was made with an IEEE nine-bus test system using a potential-energy boundary-surface (PEBS) direct method.     

考虑发电机励磁控制的电力系统暂态稳定分析

当考虑发电机励磁控制时,提出了一种新的电力系统暂态能量函数作为哈密顿函数,并提出将具有发电机励磁控制的电力系统动态表示成一类标准的哈密顿系统方程。在此基础上,提出了可考虑发电机励磁控制的电力系统暂态稳定性分析的李雅普诺夫函数。     

基于PEBS法的交直流输电系统暂态稳定分析

计及直流系统的动态构建了交直流输电系统的暂态能量函数,直流换流站交流母线电压和发电机转速功角一样作为显式变量出现在暂态能量函数中,暂态能量函数的变量从平衡点到势能边界面出口点的积分路径不作线性假设.视为慢动态的发电机转速和功角,沿着持续故障轨迹或受扰轨迹积分,而视为快动态的直流系统变量的积分路径通过修正后得到,并讨论了应用势能边界面法求取临界能量和临界切除时间的问题.分别利用所提方法和逐步积分的时域仿真法求取了4机和10机交直流输电系统的临界切除时间,通过比较验证了所提方法的有效性.     

用拓扑能量函数法评估多机系统的暂态稳定域

本文论述了基于网络结构保持的拓扑能量函数法评估多机系统暂态稳定域的数学模型与算法。主要论点是发电机用E_q′模型代替经典的E′模型,它对于首次摇摆稳定分析更为实用。同时在系统模型中计入了负载的电压特性,并有效地判定系统的暂态能量,运用位能边界曲面方法决定稳定域。用16机51结点简化的华东系统对上述方法的有效性进行了研究,仿真结果验证了所提论点的正确性。     

独立磁路混合励磁电机的矩阵分析

独立磁路混合励磁电机结构特殊,分析计算也区别于常规电机。运用矩阵分析方法,导出该电机的稳态和动态数学模型,分析其磁场大范围可调制的机理,并给出一台由转枢式交流励磁机供电(无刷)的独立磁路混合励磁试验样机的计算实例及试验结果,获得了满意的一致性。计算数据与试验结果表明：改变电励磁磁势(magnetomtive force,MMF)的大小和方向可改变电枢感应电势(electromotive fore,EMF)的大小,而且感应电势与电励磁磁势近似成线性关系;由于励磁电流由转枢式交流励磁机提供,无需电刷,提高了系统的可靠性;独立磁路混合励磁电机和转枢式交流励磁机一体化设计,减小了体积,使系统结构更紧凑可靠。     

交流励磁机的有限元多元化参数计算及瞬态仿真

由于交流励磁机电枢绕组电流在导通期间的时变性以及铁磁材料饱和特性的影响,瞬态电感是转子位置和电枢绕组电流的多元函数,解析法难以准确计及电流时变性和铁磁材料饱和性的影响。这里采用二维有限元多元化参数法建立交流励磁机的电磁场约束模型,并定量计算了转子位置、励磁电流以及电枢电流变化对瞬态电感矩阵的影响,利用该计算结果对交流励磁机在三相稳定短路、两相对地短路和单相接地短路等瞬态特性进行了仿真试验,进一步证明基于"场"的方法计算瞬态电感矩阵的可行性。     

11相无刷励磁机故障工况数字仿真研究(一)

本文应用张量电网络理论所建立的无刷励磁机通用仿真模型,对１１相无刷励磁机进行了额定工况及故障工况的仿真研究。故障工况包括一个二极管支路断开及一个二极管支路短路情况。分析了熔断器布置的有效性。励磁机电感参数由二维有限元法算得。进行了实验,理论分析与实验结果吻合。     

Fitting a Simple Linear Automatic Voltage Regulator Model to a Complex Exciter System Representation

ABSTRACT

The model adjustment technique for parameter estimation of transfer functions is successfully used to reduce the order of complex exciter system representations from the order up to 5 to the first order. The reduced order exciter system representations are preferred in electrical power systems transient studies.     

发电机励磁绕组阻尼环烧毁的原因分析

分析了因无刷励磁机转子旋转整流器中二极管故障导致烧毁相关设备的现象和原因,提出了相应的解决措施.完善了无刷励磁机系统的功能.使发电机和与其相连的电力系统运行的稳定性和可靠性得到保证.