SVC预防电压失稳的快速控制方法

在电压濒临失稳时,静止无功补偿器(SVC)可能因为输出无功功率不够快而无法阻止电压失稳,针对这种情况,提出了一种SVC预防电压失稳的快速控制方法。该方法以电压失稳预测(VIP)指标数值越限为启动条件,通过调整SVC电压参考值提升其无功输出速度,从而预防电压失稳。使用PSCAD/EMTDC和MATLAB的联合仿真进行算例分析,验证了此控制方法提升电压稳定性的有效性。该方法简单可靠,且仅调节SVC控制系统外部数据,不改变SVC原有的系统结构和参数,适用于实际系统,有很好的发展前景。     

蚁群优化PI控制器在静止无功补偿器电压控制中的应用

静止无功补偿器(static var compensator,SVC)通常用来进行负荷补偿或系统补偿,在系统补偿时往往用于电压稳定控制,针对电压稳定控制的工况,文中提出一种采用蚁群算法优化PI控制器参数的方法,克服了常规PI控制对被控对象数学模型的依赖性,简单易于实现。蚁群优化算法中,以时间与误差绝对值乘积积分(integral of time-weighted absolute error,ITAE)准则作为寻优目标函数,对PI控制器的比例、积分参数进行调整、寻优,使SVC系统的响应过程达到最优。仿真和实验结果表明,该最优PI控制器能快速跟踪SVC系统的电压设定值,基于该PI控制器的SVC能迅速进行无功补偿,具有较强的适应性和较高的补偿精度。     

基于瞬时无功功率理论和模糊控制的新型SVC控制算法

为满足不平衡三相配电网的无功功率实时补偿的要求,设计了一种新型的FC-TCR型静止无功补偿器(SVC)控制系统。该系统采用瞬时无功功率理论来精确检测基波正序和负序电压、电流,并推导出补偿导纳的表达式;SVC的整体控制采用了开环和闭环控制相结合的控制算法,并在闭环控制算法中,提出了基于智能规则的模糊-PI双模调节技术在无功补偿控制系统中的应用方案。该方案结合了模糊控制和PI控制2种方法的优点,根据系统状况改变PI控制器的参数,以达到更好的动态控制效果。仿真研究结果表明,该新型SVC控制系统对于提高功率因数和补偿三相不平衡,具有响应快、精度高的控制效果。     

电网电压稳定与无功功率补偿的研究

从电压稳定的基本概念和现有的研究成果出发,分析了电压稳定的机理和无功功率补偿的方法,明确现今电网无功问题的三个特点,说明系统的无功功率平衡与电压稳定和电压崩溃是密不可分的,并就无功补偿的不同方式,对防止电压崩溃的发生提出了相应的对策。分析了静止无功补偿器（SVC）与静止无功发生器（SVG）的工作特性与基本原理,对SVC与SVG进行了比较与述评,得出了应用SVG可以更好地控制无功功率的分布,提高电网的电压稳定水平,有效地避免电压崩溃的结论。     

An optimised FOPID controller for dynamic voltage stability and reactive power management in a stand-alone micro grid

This paper proposes the application of fractional order PID controller (FOPID) for reactive power compensation and stability analysis in a stand-alone micro grid. For enhancement of voltage stability and reactive compensation of the isolated system, a SVC based controller has been incorporated. This paper emphasizes the role of fractional PID based SVC controller for reactive power management and improved stability in the stand alone micro grid, as it provides a special advantage of having two more degree of freedom for accurate tuning in comparison with the conventional controller The system performance, particularly the variations in different parameters values are studied properly with different input parameters and loading conditions. Further improvement of stability margin and optimisation of the system parameters have been achieved by the controller, based on Imperialist competitive algorithm.     

Reactive current control through SVC for load power factor correction

This paper discusses a new technique for controlling SVCs (Fixed Capacitor–Thyristor Controlled Reactor) in power systems with the aim of canceling the reactive current component of the load. A complete model of the SVC with its control circuit is set up and simulated in the EMTDC program. The generated harmonics from the proposed SVC controller are considered to design simple tuned filters to cancel the undesirable harmonic components. The effect of these filters is considered as well in the SVC control design, so that the reactive current component absorbed by the combination of the load, SVC, and filters is eliminated. The proposed control technique is compared with respect to a standard PI-based SVC controller.     

静止无功补偿装置的实用化技术与措施

静止无功补偿装置(SVC)是柔性交流输电控制装置的重要内容之一,具有动态平滑的调节特性及向电力系统提供阻尼的作用。介绍了SVC实用化技术,如进行自动电压控制(AVC),预防电网电压失稳,提高电网的输送能力,防止事故扩大,紧急情况下可以形成有效的反电压崩溃防线,在冶金、电气化铁路等行业治理电压波动、闪变、谐波污染并平衡随时间变化的非对称负荷,防止发生次同步谐振,给直流输电提供无功等在提升电力系统安全优质经济运行水平中的作用。简要介绍了SVC国产化的现状,并提出了推行SVC的具体建议。     

Study on a Voltage Estimation of Tap‐Changing Transformer in Consideration of SVC Introduction

Recent years, installation of photovoltaic (PV) system is active by the environmental problem and feed in tariff system. Due to PV's output fluctuation, the static var compensator (SVC) made by power electronics technology is planning to install in distribution system. The SVC is expected for maintain the voltage. But SVC differs in a theory of operation of the existing voltage controller load ratio control transformer (LRT) and step voltage regulator (SVR). Because the SVC operation makes the system impedance changes, the existing voltage controller may not operate effectively. In this study, the intelligent‐control method which used the radial basis function (RBF) network is proposed. This method can reduce the effects of the SVC operation by including the performance characteristics of SVC in the conventional method. An advantage of unnecessary arrangement attention of the SVC setup node and easy cooperation with the existing equipment is obtained by applying this method.     

SVC和TCSC提高电压稳定性作用的动态分析

利用小扰动分析法和非线性动态方法中的分岔等概念对SVC和TCSC提高电压稳定性的作用进行了全面的分析。研究了由SVC和动态负荷相互作用引起的Hopf分岔现象,并对SVC和TCSC时间常数的选择进行了讨论。分析表明,在简单系统中,TCSC比SVC更能有效地提高系统的电压稳定性;TCSC时间常数的变化比SVC时间常数的变化对电压稳定功率极限影响小;装设SVC和TCSC后可以显示地增大系统的电压稳定功率极限。在考虑SVC或TCSC动态的情况下PV曲线鼻尖点并不一定是系统失稳点。     

基于自适应虚拟阻抗的交流微电网无功功率—电压控制策略

微电网作为分布式电源的有效载体,是分布式能源合理利用的有效途径。而在微电网中,由于物理线路阻抗不匹配等因素的影响,传统的下垂控制难以合理分配无功功率。为了改善无功分配的精度,提出一种基于自适应虚拟阻抗的微电网无功功率—电压控制策略。该方案在传统的虚拟阻抗基础上叠加自适应项,从而修改电压参考值;同时,通过电压恢复机制来补偿由此造成的输出电压的降低。仿真和实验结果实现了负荷有功和无功功率的合理均分,从而验证了所提控制策略的可行性和有效性。     

基于无功源的分布式光伏电站无功补偿协调控制系统及方法

基于光伏电站内各无功源(SVC/SVG、逆变器)的无功出力及剩余可调裕度,文中提出一种分布式光伏电站无功补偿器SVC/SVG与逆变器无功负荷协调优化控制的系统及方法。该协调控制方法以分布式光伏电站AVC系统为基础,获取本场站的当前总无功功率,及本场站内各无功源的无功出力及剩余可调裕度,根据特定的优化控制原则,将各无功源的无功值进行重新调整,实现无功功率在无功补偿器SVC/SVG和逆变器之前的优化分配。最后,提出一种基于AVC的分布式光伏电站电压控制系统。系统及方法能够在保证分布式光伏电站并网点电压稳定的条件下,充分利用逆变器的无功补偿能力,降低无功补偿器SVC/SVG的无功出力,达到降低分布式光伏电站无功补偿装置的耗电量的目的。     

SVC广域辅助控制阻尼区域间低频振荡

SVC已经广泛应用于电力系统的无功支持和电压控制,广域测量系统在国内外也已有许多工程应用.本文利用广域测量信号为输入设计SVC的附加阻尼控制(PSDC).首先阐述了SVC提供阻尼的机理,然后提出了综合留数指标的概念,并据此选择具体的控制输入信号;接着基于测试信号法和留数根轨迹方法相结合进行PSDC的参数设计;并利用PSS/E进行了特征值分析和时域仿真分析验证了所设计的附加阻尼控制器的有效性.最后针对国内某实际电网外送工程中安装的SVC设计了相应的阻尼控制器,时域仿真证明了SVC广域附加阻尼控制的有效性.     

A novel SVC supplementary controller based on wide area signals

Static Var Compensator (SVC) is a kind of FACTS device which is used in power system primarily for the purpose of voltage and reactive power control. Based on wide area signals, this paper presents a systematic approach for designing SVC supplementary controller, which is used to improve the damping of power system oscillation. The principle for damping oscillation by SVC is first analyzed and the concept of synthetic residue index is then presented which is used to choose the proper input wide area signals. Parameters of the controller are determined by means of test signal method and residue root locus. Eigenvalue analysis and time domain simulations are performed on a two-area system and the results demonstrate the effectiveness of the proposed controller.     

考虑多种无功补偿装置协同优化的电压控制方法

为了应对电力系统扰动带来的稳态及暂态电压波动问题,以静止无功补偿器（static var compensator,SVC）、电容器组（capacitor bank,CB）、有载调压变压器（on load tap changing,OLTC）和同步调相机（synchronouscompensator,SC）为综合性无功补偿装置,提出了一种考虑多种无功补偿装置协同优化的电压控制方法。建立多目标电压控制模型,引入多目标权重系数计算方法,并基于水循环算法（water cycle algorithm,WCA）进行模型求解。通过仿真算例验证了所提方法的有效性。     

静止无功补偿器的新型最优非线性比例积分电压控制

针对传统PI应用于静止无功补偿器(static var compen- sator, SVC)这个非线性复杂系统上,所体现出的快速性与稳定性之间的矛盾,以及对精确数学模型的依赖性,适应性及鲁棒性较差,该文设计了以非线性函数与传统PI控制器串联起来构成非线性PI控制器,简单易于实现。并且提出基于改进的单纯形加速算法(simplex method,SPX),以时间乘以误差绝对值积分(integrate of time multiplied absolute error,ITAE)准则作为寻优目标函数,对非线性PI控制器的参数KP、KI进行实时调整、寻优,使SVC系统的瞬态响应过程达到最佳。仿真和实际应用结果表明该最优非线性PI控制器,不但能快速、无超调的跟踪SVC系统的电压设定值,而且可实现对无功功率、三相不平衡等多个因素的综合补偿,具有较强的鲁棒性、适应性和较高的补偿精度。     

DESIGN OF VARIABLE STRUCTURE CONTROLLER FOR STATIC VAR COMPENSATOR

ABSTRACT

Static Var Compensator (SVC) is a relatively new kind of reactive power and voltage control device. It can be used not only to improve dynamic and transient stability of power system, but is especially suitable for voltage control of long distance bulk power transmission lines. To enhance the performance of SVC, in addition to voltage control (main control), a supplementary control (auxiliary control) is required. Variable Structure (VS) Stabilizer is proposed in this paper, as supplementary controller to SVC. The machine, excitation and SVC dynamics are considered. In this paper, a systematic procedure for evaluating gains for sliding mode to occur is presented. The switching vector is constructed using pole-assignment method. Trial and error, and heuristics approach is completely avoided for evaluating the gains in the sliding mode     

负荷特性对江苏电网电压稳定性影响的仿真分析

江苏电网具有电源分布不均、负荷增长迅速、无功储备不足等问题,是典型的易发生电压稳定问题的系统。在仿真中考虑了动态负荷模型和参数的影响,分析了2006年江苏电网负荷增长和负荷中心大扰动后的电压稳定性,并与采用原有数据的计算结果进行了比较。结果表明,现在一些电网电压稳定分析常沿用以往角度稳定分析所用的静态负荷数据的作法存在较大的不足,不能完全满足电压稳定分析和制定应对措施的要求。还就采用静止无功补偿器(SVC)提供动态无功支持,提高江苏系统电压稳定性进行了研究。结果表明,现阶段采用SVC提供江苏电网扰动时负荷的动态无功支持,提高电压稳定性是一项可行的措施。     

Developing static reactive power compensators in a power systemsimulator for power education

This paper describes a newly installed laboratory module microcomputer-based static reactive power compensator (SVC) in detail to teach students how an SVC affects system voltage, load balancing, power factor, and transmission line losses. The SVC is merged into an old power system simulator for extensive power engineering education. The structure of the SVC is thyristor controlled reactors with fixed capacitors (TCR-FC). Two control algorithms, feedback control and feedforward control, are developed and compared. For the purpose of program flexibility and portability, a VME-Bus based microcomputer is used to synthesize the controller of the SVC. Several suggested experiments are given to show the effects of the SVC on distribution system compensation. The SVC greatly promotes the performance of the power system simulator     

静止无功补偿器的神经元变结构PID控制策略

针对静止无功补偿器传统PID电压调节器在动态调节过程中存在快速性与平稳性矛盾的问题,提出了一种基于神经元整定变结构PID的静止无功补偿器电压控制策略。该控制策略用一个神经元控制器实现变结构PID控制,同时用另一个神经元控制器实时调整变结构PID控制器的参数。仿真结果表明,该控制策略能有效加快控制系统的响应速度,实现了SVC灵活快速的电压调节功能,最终维持了系统电压的稳定,控制系统具有较好的动态和静态稳定性。     

SVC附加闭锁控制提高双馈风电场高电压穿越研究

为缓解风机高电压脱网对电网安全稳定运行造成的严重威胁,文中解析了集群风电基地广泛应用的静止无功补偿器(SVC)引发电压过冲的机理。SVC响应滞后及其自身物理特性缺陷,使其在电压跌落时难以提供有效容性无功支撑,而在电压恢复期向系统输出冗余容性无功。为克服SVC控制性能的这种局限性,提出一种SVC附加闭锁控制策略,主要适用于外部故障引起SVC接入点出现严重低电压的场景。该控制策略给出SVC闭锁判定条件及闭锁后SVC重新投入条件,避免"错位补偿",有效降低SVC引发非故障风机并网点高电压的威胁,保障风场安全稳定运行。最后仿真验证了所提控制策略的有效性,并对后期风电场的建设与运行提出指导性建议。