TCR+FC型SVC的系统设计及其在风电场的应用

介绍TCR+FC型SVC,分析其在提供动态的电压支撑、减轻风电功率对电网电压的影响等方面的作用。     

基于模糊-PI控制的SVC电压控制器的设计与实现

为提高电力系统电压稳定性,综合了模糊控制和PID控制的优点,提出一种基于模糊-PI控制的SVC的电压控制器设计方法.分析了SVC电压控制器的基本原理和组成,详细介绍了模糊-PI控制的设计实现过程.用DSP作为主控芯片开发出了控制器,给出了软硬件设计思想.对SVC进行了仿真验证,仿真结果表明模糊-PI控制比传统PI控制具有更好的动态性能,较小的超调量和较短的调节时间.     

SVC对电压稳定性影响的研究及方案设计

电力系统运行的稳定性及有效性对整个国民经济和生活具有重要意义。目前电力系统运行不稳定的原因主要是由于无功功率不足或分配不合适引起的,如何提高系统稳定性的研究是个急需解决的问题。本文在分析SVC控制系统电网稳定的工作原理的基础上,在Simulink中建立单机负荷系统仿真模型,计算分析系统在有无SVC装设的情况下系统的稳定性,结果表明采用SVC来控制系统电压对其稳定性有显著改善。     

SVC对电力系统动态稳定性的仿真研究

介绍了电力系统中静止无功补偿器(SVC)的基本功能,并且在MATLAB中搭建双机负荷系统进行仿真。当系统发生单相接地故障时,通过比较SVC投入前后各参数指标的差异,来确定SVC对电力系统的动态稳定性的影响。仿真结果表明SVC对于维护系统暂态稳定,保证系统电压质量方面起着重要作用。     

空调群负荷大量接入的大区域电网电压稳定方法研究

针对现有方法平均电量输出时间较长,电子供应量不稳定,不能有效保障电网电压稳定的问题,提出基于空调群负荷大量接入条件的大区域电网电压稳定性研究方法.搭建大区域电网环境,参考电网组织的基本结构形式在电网环境中设置Simu-link负荷模块与稳压滤波器.在环境支持下通过机组并网控制、电网潮流量计算、电压稳定裕度指标确定实现对...     

基于电压不对称故障修正的电网稳定控制仿真

因电网动态电流和电压的变化难以控制,且电压不对称问题修正过程干扰因素过多,提出一种电网稳定控制方法。根据动力守恒定律建立电网功率输出模型,分别计算在有、无功率输出时电网运行相关量的正、负序量值,将其作为电网稳定控制阈值。考虑到电网故障分为电压变化、电流变化以及运行功率变化三个阶段,采用无功注入方式补偿出现故障时既定电压的差值会出现空缺问题,设置逆变输出器,控制故障电流的跌落值,完成电网稳定的控制。经仿真证明,当电网出现电压不对称故障时,电网的360个测试点经过研究方法控制后电压、电流均回到了稳定阶段,整体波形变化相对平稳没有出现过高或过低的幅值,电网实现高效稳定运行。说明所提方法对电压、电流的稳定控制效果好,鲁棒性较强,实用价值更高。     

TCR+FC型SVC的研究及MATLAB仿真——一种电力节能设备

基于瞬时无功功率理论,将具体介绍静态无功补偿装置(SVC)的原理,和一种SVC(三相对称负载的晶闸管控制电感器TCR+容性无功功率补偿装置及滤波器组FC)的设计与仿真。采用闭环控制来实现用户端恒定电压的要求,为有效抑制电网由于负载扰动等因素引起的电压突变,在电压环内设计了一个导纳补偿环节,用以提高系统应对电压突变的响应速度。通过观看MATLAB的仿真结果,可以得出此型SVC控制系统对稳定和抑制电压波动,提高功率因数,具有响应速度快、精度高的特点。     

基于P-V曲线的光伏接入地区电网安全稳定性分析

新能源的大规模接入改变了电网原有的潮流分布、线路传输功率与整个系统的惯量,因此,新能源接入后电网的电压稳定性及频率稳定性都会发生变化。分析研究光伏发电系统的并网仿真模型,建立光伏并网数学模型,并通过P-V曲线对光伏发电系统接入电网产生安全稳定性影响的机理进行分析,进行大规模光伏接入对电网稳定性影响的仿真分析,包括静态电压稳定和频率稳定。以某典型的区域电网为例,验证了所提模型及理论分析的有效性。     

无模型自适应控制策略在动态电压恢复器中的应用研究

针对传统的动态电压恢复器前馈控制方法存在稳态误差、对电网中的扰动不敏感等问题,提出了一种基于无模型自适应控制策略的动态电压恢复器系统的设计方案。该方案不需要建立动态电压恢复器系统的数学模型,仅根据受控系统的负载瞬时电压和输入电压来提取系统中的有效信息,经无模型自适应控制器处理后去控制逆变器产生补偿电压,该电压经LC滤波器滤除谐波后叠加到电网中,从而可保证负荷侧电压的稳定性。仿真结果验证了该方案的正确性和可行性。     

基于自适应滤波器分序算法的锁相方法

针对常规锁相方法在电网异常时不能有效地检测出电网相位和幅值的问题,采用自适应滤波器提取电网电压的正序基波分量,根据正序基波分量检测电网的相位和幅值.针对电网相位突变的情况,在分析锁相环数学模型的基础上,提出了电网正序电压的q轴分量的直接前馈方法,有效地提高了系统的动态特性和相位检测精度,并从理论上分析了电网幅值变化对锁相环的稳定性和稳定裕度的影响.仿真结果证明了所提锁相方法的可行性.     

双馈风电机组低电压穿越能力的应用研究

近几年来,风电机组容量快速增长,为了维持电力系统的安全稳定运行和保证风电场并网安全,对风电场提出低电压穿越的要求是必要的。低电压穿越要求是电力系统功率平衡与频率稳定的需要,也是局部电网电压稳定及电压恢复的需要。为最大限度减少大规模风电接入系统对电网的影响,对风电机组提出了更高的要求,即风电机组具有一定的低电压穿越能力。介绍了变速恒频双馈风电机组的基本结构,建立了双馈风电机组动态数学模型。以Matlab/Simulink为仿真应用平台搭建了系统仿真模型,结合风电场低电压穿越能力要求的相关标准规定,针对不同电网电压跌落的情况下,仿真应用研究了变速恒频风电机组的低电压穿越能力,仿真结果表明:双馈风电机组在电网电压跌落时满足继续并网运行的条件,且为电网电压恢复提供了无功功率,提供的无功功率大小与电网电压跌落程度有关。     

含恒功率负荷的直流微电网系统性稳定性研究

传统的直流微电网稳定性分析法主要集中于基于阻抗匹配准则的小信号稳定性研究,现以含有恒功率负荷的直流微电网为研究对象,对直流微电网稳定性进行系统性分析,即在直流微电网满足大信号稳定性的基础上再去讨论其小信号稳定性。根据直流微电网稳态数学模型,通过李雅普诺夫间接法分析直流微电网满足大信号稳定性时的区域条件;提出一种基于高通滤波的有源补偿方法来增大系统阻尼,减小恒功率负载的负阻尼效应对直流母线电压稳定性的影响;建立含有有源补偿器的直流微电网的小信号模型,采用阻抗匹配准则分析加入有源补偿方法后直流系统的小信号稳定性。仿真结果验证了有源补偿方法对直流母线电压的补偿效果。     

附加阻尼控制SVC在双馈型风电场中的应用研究

将附加阻尼控制SVC应用于兆瓦级双馈型风电场并网系统,在此基础上研究了系统的暂态过程.首先建立了双馈风电机组的动态模型,水轮发电机组以及附加阻尼控制SVC的数学模型,然后仿真研究了双馈型风电场并网以后对区域系统暂态过程的影响,对比分析了风电场接入和故障情况下采用普通SVC和附加阻尼控制SVC的作用和效果,仿真结果验证了建立模型和采取方法的正确性和有效性.     

Impact of voltage dip induced delayed active power recovery on wind integrated power systems

Installed wind power capacity is increasing rapidly in many power systems around the world, with challenging penetration targets set at national, and/or regional level. Wind power, particularly at higher penetration levels, introduces various grid issues, with frequency and voltage stability being particularly critical concerns. Voltage dip induced frequency stability following a network fault in such systems is one potential risk that has so far received limited attention by the research community. With state of the art modelling, the potential impact of a delayed active power recovery from wind generation following a network fault induced voltage dip is investigated. The subsequent voltage oscillations introduced by wind turbines, exacerbating frequency stability, are also examined. Analysis is carried out for a wide range of wind penetration levels and system scenarios, with the results demonstrated on the New England benchmark system.     

Stability analysis and a hybrid controller design of grid‐connected offshore wind farm through a VSC‐HVDC transmission link

This paper proposes a hybrid controller which is a combination sliding mode control and PI control techniques for AC grid integrated offshore wind farm (OSWF) with voltage source converter ‐ high voltage direct current system. The controller must be capable of controlling AC voltage, DC‐link voltage, reactive power and effective power transfer. To examine the FRT capability, a symmetrical fault is applied at onshore AC grid side and compared the performances of the studied system based on the hybrid and PI controllers. The dynamic modelling and linearized system by state‐space modelling for the studied system are explained in detail. The small signal stability analysis and controller stability are observed with the help of the eigenvalue analysis. The analysis of the studied system with a hybrid and conventional controllers are conducted in the software environment of the MATLAB/SIMULINK . The effect of parameter uncertainty on total system stability is examined with the help of eigenmatrix of the studied system.     

An educational software package for Thyristor Switched Reactive Power Compensators using Matlab/Simulink

In this paper, an educational software package called TSCOM (Thyristor Switched Reactive Power Compensators) has been developed. The TSCOM software package contains simulation models of Thyristor Switched Capacitor (TSC) and Thyristor Switched Reactor (TSR)-based Static VAr Compensator (SVC) which are two of the shunt Flexible AC Transmission Systems (FACTS) devices. The design and simulations of TSC and TSR-based SVC are proposed using the Matlab/Simulink 7.04® and SimPowerSystems. The TSC and TSR-based SVC devices are demonstrated at two bus, three bus, infinite-bus, single-phase, three-phase, static load, dynamic load and stair-case load conditions. The effects of TSC and TSR-based SVC devices on load voltage are also analyzed. Student feedback indicates that this package is user-friendly and considerably effective for students and researchers to study theory of switched compensators, the reactive power control and voltage regulation. The proposed package will help to design the practical prototypes for students and researchers.     

风电并网对系统稳定性及紧急控制策略影响的仿真分析

在DIgSILENT软件中建立异步风电机组和双馈感应风电机组模型,以新疆某地区实际电网为例,分析比较了两种不同风机并网对电力系统电压和频率稳定的影响,同时,研究了两种风机并网前后对电力系统紧急控制策略的影响。仿真结果表明:当电网发生扰动时,双馈感应风机频率响应不明显;但在电网扰动影响电压稳定时,双馈感应电机能够提高一定的电压稳定性;当电网发生大扰动,采取紧急控制策略后电网的稳定性不如电网未接入风电时电网采取紧急控制策略后的稳定性。     

Voltage control for static var compensator using novel optimal nonlinear PI

Static var compensators (SVCs) are used for voltage and reactive power control in power systems. In this paper, we will consider the structure of SVCs that mainly consists of Y -connection of mechanically-switched capacitor (MSC) and delta connection of thyrister-controlled reactor (TCR). First, the control model of SVC was established in this paper. Then, a novel optimal nonlinear voltage controller for SVCs is proposed. The proposed SVC voltage controller consists of a nonlinear function and a conventional PI controller. The improved simplex method (SPX) is presented to adjust and optimize the parameters of the nonlinear PI controller in real-time, and to make transient state response procedure of SVC optimum. The integration of time multiplied absolute error (ITAE) is adopted as the optimized objective function of SPX. Simulation and engineering application results show that the proposed voltage control method is able to track reference voltage value of SVC immediately. It also demonstrates that the whole SVC control system can synthetically compensate reactive power.