System identification of power network for coordinated setting of PSSs

The PSS is a reasonable controller to stabilize the intertie and local oscillations of power networks. PSSs are usually set with the one‐machine infinite‐bus system model. The coordinated setting of the multiple PSSs considering the characteristics of the network is expected to improve stability. For this purpose, the Modal Performance Measure method is used to adjust the PSS parameters. The model is identified by the N4SID identification method. In this paper, the conditions of identification and validation of identification are presented. Identified models are validated by comparison of vector diagrams, impulse response, and so on. Identification of a power network that consists of many generators is successful. © 2012 Wiley Periodicals, Inc. Electr Eng Jpn, 181(2): 10–19, 2012; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.22287     

Power system stabilization control based on the wide area phasor measurement

This paper presents a method of tuning power system stabilizers (PSS) in order to damp low‐frequency oscillations in a multimachine power system based on wide area phasor measurements. The authors have developed a method for detecting interarea low‐frequency modes from measured small oscillations associated with load fluctuations by approximating the oscillations as a coupled vibration model. In this paper, the coupled vibration model is extended to include the effect of PSS. PSS are tuned directly by using the extended model, since the model includes parameters of PSS. The advantage of this method is that steady state phasor fluctuations are available for tuning PSS and assessing the effect of the tuning control. That is, a large disturbance like a line fault is not necessary since the stability of major modes can be investigated directly by using eigenvalues of the extended model. The identification process does not require information on the input to the system for perturbation. Some numerical analyses demonstrate the effectiveness of the method by using phasor dynamical data obtained by a power system simulation package. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 163(1): 16–24, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20640     

励磁机时间常数对电力系统动态稳定性的影响

励磁机时间常数对电力系统动稳定有显著影响.在高放大倍数的AVR控制下,快速励磁较慢速励磁更容易恶化系统阻尼;但是在同时附加励磁控制的情况下,快速励磁可使系统的机电模式根轨迹远离虚轴,机电模式阻尼较大;而慢速励磁下,系统机电模式根轨迹接近虚轴,机电模式阻尼较小,快速励磁优于慢速励磁.通过对一个8机系统在AVR、AVR PSS和分散协调励磁调节三种控制规律下的特征分析和动态仿真表明:有附加励磁时,快速励磁比慢速励磁更有利于电力系统动态稳定性.最后借助特征向量理论揭示了所得结论的数学本质.     

电力系统稳定器(PSS)试验若干问题研究

电力系统稳定器(PSS)是励磁系统的一种附加功能，它抽取与低频振荡有关的信号并对其加以处理，产生的附加信号跌加到励磁调节器中，使发电机产生阻尼低频振荡的附加转矩，用于提商电力系统的阻尼。将电山系统稳定器(PSS)投入运行是解决电网低频振荡问题、提高电同动态稳定性诸多措施中最简单、经济前方法。对山东电网电力系统稳定器(PSS)现场试验中出现的跳机、PSS模型不理想、阶跃试验发电机有功功率波动不明显等问题进行分析，提出试验前后屏蔽白噪声输入通道、在励磁调节器配置通用的PSS模型、优化励磁调节器PID参数等改进措施，以期对电力系统稳定器(PSS)的使用和现场试验有所帮助。     

Coordinated Setting of Multiple PSSs for Actual Size Power Network

The power system stabilizer (PSS) is a low‐cost method of stabilizing the intertie and local oscillations of a power network. The PSS parameters are usually adjusted based on the one‐machine infinite‐bus system model. In contrast, a real power system consists of multimachine systems. Thus, coordinated setting of the PSS parameters, with the real characteristics of the power system network taken into consideration, is expected to improve stability. For this purpose, the modal performance measure (MPM) method is used to adjust the PSS parameters. The power network mathematical model that is required for this calculation is given by the system identification method. Utilizing the MPM method characteristics, restrictions such as the damping coefficient and maximum gain, which constitute practical design specifications used for conventional controllers, are naturally introduced. Furthermore, radial basis function (RBF) frequency weighing is introduced in order to adjust the frequency responses. The expected favorable results were found in large‐scale power system simulations.     

Stabilization control of multi‐machine power systems by adaptive power system stabilizer using frequency domain analysis

To improve electric power system transient stability, synchronous generators are generally equipped with controllers such as AVR, PSS, and GOV. Fixed parameter controllers degrade control performance, since various oscillation modes occur depending on system conditions. This paper presents an adaptive power system stabilizer (PSS) using frequency domain analysis for improving the transient stability of a multimachine system. In the proposed method, first, the frequency components of the generator swings are detected by the FFT. The conventional PSS parameters are tuned online by a fuzzy controller and frequency domain analysis. We verify the proposed adaptive PSS using frequency domain analysis, which can damp the generator swings effectively. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 142(2): 10–20, 2003; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10129     

电力系统小信号稳定分析与控制综述

针对互联电网形成后越来越突出的低频振荡问题,综述了电力系统小信号稳定性的分析和控制方法.首先推导了用于小信号稳定性分析的数学模型及基于该模型的特征值分析方法,求取主特征值是优化此类方法的趋势;然后介绍了几种近年来出现的新方法和仿真软件,PSS/E由于其强大的功能将成为应用的主流;探讨了影响小信号稳定性的各种因素和稳定域的估计等问题,对稳定域的解析性刻画是今后研究的热点;指出了提高小信号稳定性的措施和控制策略,简单介绍了PSS、FACTS和HVDC用于该领域的可行性及其控制器的设计方法,广域测量系统的出现将为上述工具的应用提供新的思路和实现手段;最后对该领域的发展趋势和前沿的研究课题进行了展望.     

日照电厂350MW励磁系统数学模型及PSS现场试验

通过对日照电厂350MW机组励磁系统的分析研究，确定了励磁装置的实际数学模型。经过SME仿真计算，初步选定PSS的参数。现场试验表明，经过仿真计算得出的PSS参数是适合的。现场试验采用了有PSS及无PSS情况下，AVR输入不同频率的干扰信号，测量发电机功率振荡的衰减，试验结果表明，该方法对测定不同频率时PSS的阻尼特性是有效的。     

自适应电力系统稳定器设计的频域方法

本文提出了一种自适应电力系统稳定器设计的频域方法。这种自适应稳定器通过在线估计系统中发生振荡的频率与阻尼,调整稳定器参数,以保持向系统提供足够的阻尼,从而使其能够适应电力系统运行方式及工况的变化,达到抑制振荡,提高系统稳定性的目的。文中给出了设计实例及详细的非线性仿真结果。     

New approach to power system stabilizer design

A generalized method for the design of excitation control or a power system stabilizer (PSS) based on complex frequency is described. The method selects PSS parameters such that exact assignment of eigenvalues associated with the mechanical modes of oscillation to desired locations is achieved. Numerical examples are used to illustrate the concepts of the proposed new technique.     

Method and software for coordinated tuning of power systemregulators

A method for coordinated tuning of power system regulators (AVR, PSS, SVC, etc.) to improve damping of small disturbed oscillations for a variety of power systems operating conditions is given. The method is based on multi parameter numerical optimization to shift eigenvalues of interest to the left on the complex plane. The advanced POISK software which utilizes the proposed method is described     

Optimal controllers designs for automatic reactive power control in an isolated wind-diesel hybrid power system

The paper presents the bacterial foraging optimization algorithm (BFOA) and particle swarm optimization (PSO) algorithm based robust controllers for voltage deviations due to the variation of reactive power in an isolated wind-diesel hybrid power system. The isolated wind-diesel system consists of wind energy conversion system (WECS) utilizing a permanent magnet induction generator (PMIG). Further, a synchronous generator (SG) is used with the diesel engine set for power generation. The mismatch between generated and consumed reactive power in the system causes voltage fluctuations, which will occur at generator terminals. These oscillations further causes reduction in the stability and quality of the power supply. The static synchronous compensator (STATCOM) and an automatic voltage regulator (AVR) are used to suppress voltage fluctuations in an isolated wind-diesel hybrid power system. The STATCOM is used as a reactive power compensator and the AVR is used to keep the terminal voltage constant for the synchronous generator. Both STATCOM and AVR are having proportional and integral (PI) controllers with single input. In modeling for the system, a normalized co-prime factorization is applied to show the possible unstructured uncertainties in the power system such as variation of system parameters and generating and loading conditions. The performance and robust stability conditions of the control system are formulated as the optimization problem, which is based on the Hα loop shaping. BFOA and PSO algorithms are implemented to solve this optimization problem and to achieve PI control parameters of STATCOM and AVR simultaneously. In order to show the efficiency of the proposed controllers, the performance of the proposed controllers is compared with the performance of the conventional controller and genetic algorithm (GA) based PI controllers for the same wind-diesel system. The dynamic responses of the system for four different small-disturbance case studies has been carried out in MATLAB environment.     

基于主导轨迹断面阻尼比灵敏度的仿真关键参数诊断

电力系统机电暂态仿真中,励磁、调速、电力系统稳定器(PSS)等控制系统参数不合理,易引起控制系统稳定性弱化,导致仿真可信度降低。基于轨迹断面阻尼比灵敏度指标,提出一种机电暂态仿真中控制系统关键参数的实用诊断方法。由仿真中各控制系统的输出变量振荡特性确定主导断面时刻、主导发电机及其对应控制系统,针对主导断面时刻和主导发电机进行单机无穷大(OMIB)等值后,经阻尼比灵敏度分析给出参数调整建议,多个算例验证了所提方法的有效性。该法是轨迹特征根思想的一种工程应用,结合数值积分提供的控制系统振荡信息与平衡点特征根技术提供的阻尼比灵敏度解析信息,可快速定位不合理的控制系统参数,适用于复杂多机系统的参数诊断。     

基于在线频率响应分析的发电机电力系统稳定器(PSS)参数整定试验

用在线频率响应分析方法对徐州华润发电厂300MW发电机励磁系统的电力系统稳定器(PSS)参数进行了优化.根据无PSS时的励磁系统频率响应特性试验结果对PSS的参数进行了整定,并对整定后的系统进行了负载阶跃和反调试验.试验结果表明,整定后的PSS参数有很强的适应性,对0.1～2.0Hz的低频振荡有很好的抑制作用,具有较好的阻尼效果,而且将仿真与现场试验相结合的频率响应特性分析方法的物理概念清晰,是设置和优化微机励磁调节器参数的一种有效方法.     

基于灵敏度分析的电力系统稳定器参数优化

推导了电力系统稳定器(PSS)参数灵敏度指标的计算过程,并在小干扰稳定分析软件SSAP中实现了2种灵敏度计算功能,即振荡模式特征值及其阻尼比对PSS参数灵敏度的计算功能,以及控制器等效交流增益不变约束下的振荡模式特征值及其阻尼比对控制器补偿相位的灵敏度的计算功能,可以对低频振荡阻尼进行优化(或约束优化)。以红海湾电厂600 MW机组为例,通过PSS参数的灵敏度分析对低频振荡阻尼进行约束优化,特征值分析与现场抗扰动试验的实测录波结果相吻合,验证了SSAP灵敏度分析理论与计算的准确性及其在工程中的指导作用。     

电力系统稳定器调参现状与研究

电力系统稳定器(PSS)是同步发电机励磁控制系统中的一个部分,它通过把相关信号传递到电压调节器来抑制机组之间的低频振荡,对电力系统的安全稳定运行有着至关重要的作用.PSS参数调整的优劣直接影响到其功能的发挥,文章从工程和研究的角度介绍了PSS参数整定的方法,并对其未来的发展进行了展望,认为从软硬件配置、系统运行、在线调参性能等方面尚需投入更多研究.     

A practical approach to the order reduction of a power system model for small signal stability analysis

A linearized power system model suitable for small signal stability analysis or automatic voltage regulators (AVR) and power system stabilizers (PSS) synthesis is derived in the paper. It is derived using the 5th order synchronous machine model with damping winding, the second order IEEE Type 1 AVR and the third order PSS. A new method of model construction and decoupling is given. Using a singular perturbation method the power system model is separated into decoupled lower order slow and fast subsystems. The new proposed model was tested on a real power system in Serbia.     

基于广域测量信息的互联电网模型预测阻尼控制

提出一种基于模型预测控制的新型阻尼控制器设计方法。为抑制区间低频振荡,该控制器由2级PSS构成,其输入信号由广域测量信号和本地测量信号组成。采用留数矩阵法选择广域控制回路,通过模式辨识进行2级PSS控制。将常规励磁系统中传统的自动电压调节器(automatic voltage regulator,AVR)用模型预测控制器(model predictive controller,MPC)替代,并与2级PSS协调作用,通过模型预测和优化求解,得到励磁控制器的最优控制输入,以实现电压调节和增强阻尼之间的动态协调。典型的四机两区系统仿真结果表明,基于模型预测控制的2级PSS设计的控制效果明显优于传统的阻尼控制,可以快速调节机端电压,显著改善互联电网阻尼。     

Development of a new adaptive LQG system generator for high‐speed damping control techniques of power system oscillation

With the advent of interconnection of large‐scale electric power systems, many new dynamics power system problems have emerged, which include low‐frequency intersystem oscillations and many others. To date, most major generators in trunk electric power systems in Japan are equipped with supplementary excitation control, commonly referred to as the conventional single and two input PSS. However, low‐frequency oscillations still occur. It is difficult for these conventional PSS to improve the additional damping of power system oscillation, because of the hardware and design of fixed PSS control constants from a one‐machine infinite‐bus model. It has therefore become necessary to develop a new adaptive LQG system generator. This paper explains the development of the new adaptive LQG system and the simulation of low‐frequency and local mode oscillation for this new adaptive LQG system. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 142(3): 30–40, 2003; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10109     

Coordinated Synthesis of Multimachine Power System Stabilizer Using an Efficient Decentralized Modal Control (DMC) Algorithm

This paper presents a new method for simultaneously selecting the power system stabilizer (PSS) parameters in multimachine power systems. Design of local output feedback power system stabilizer using local signal of the generator (e.g. speed or power) is formulated as a decentralized modal control (DMC) problem. Exact model reduction based on modal control theory is proposed to make the determination of PSS parameters highly efficient. Results obtained from the coordinated tuning of the parameters of three power system stabilizers equipped on a multimachine power system show that exact assignment of the eigenvalues associated with the poorly damped electromechanical modes can be achieved in a very efficient manner.