与有载调压器配合的静止无功补偿新策略

提出了SVC控制的一种新策略,包括两阶段的斜率控制和两种电压控制,分别是稳态电压控制和浮动电压控制。实行这两种控制的目的是通过与有载调压器的配合,在稳态情况下,减少SVC的无功功率输出,从上级网络获得无功进行补偿。当电压偏离稳态电压时,SVC使用无功备用进行迅速反应,以保证电压稳定。当电压波动达到一个新的稳定工作点时,浮动电压控制通过改变SVC输出,使其返回到稳定电压运行区域,从而达到了稳定电压和保证电能质量的目的。     

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。     

Coordination control of ULTC transformer and STATCOM based on an artificial neural network

This paper presents an artificial neural network (ANN)-based coordination control scheme for under load tap changing (ULTC) transformer and STATCOM. The objective of the coordination controller is to minimize both the amount of tap changes of the transformer and STATCOM output while maintaining an acceptable voltage magnitude at the substation bus. The coordination controller is designed to substitute for a classical ULTC mechanism by utilizing active and reactive powers, tap position, and STATCOM output. A competitive ANN is used as a classifier for tap positions and trained by a proposed iterative condensed nearest neighbor (ICNN) rule.     

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。     

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。     

Coordinated voltage control of wind-penetrated power systems via state feedback control

This paper presents an optimal coordinated voltage control scheme for preserving long-term voltage stability of power systems. Linear quadratic integral (LQI) controller is employed to construct this scheme. Also, this paper considers the detailed dynamic model of doubly-fed induction generator (DFIG) wind turbine, synchronous generators, over excitation limiter (OEL) and under-load tap changer (ULTC) system, which are important elements influencing voltage stability of power systems. The proposed approach at each time instance involves following two major steps: First, the power system nonlinear equations are linearized and optimal controllers are obtained by LQI technique. Then, in the second step the system dynamic behavior is investigated via time-domain simulations by applying the attained optimal control signals at the first step. The impact of the proposed coordinated voltage control scheme is evaluated by time domain simulations on a well-known test system, under variable wind speed and fault conditions.     

Volt/Var control in a distribution system by a fuzzy optimization approach

This paper presents a fuzzy optimization approach for solving the Volt/Var control problem in a distribution system with uncertainties. Wind turbines are being considered in the study distribution system. The main purpose is to find an optimum combination of tap position for the main transformer under load tap changer (ULTC) and on/off status for switched capacitors in a day to minimize the voltage deviation on the secondary bus of the main transformer, reactive power flow through the main transformer and real power loss on feeders. When performing the Volt/Var control problem in conventional methods, the hourly load and wind speed must be forecasted to prevent errors. However, actually there are always errors in these forecasted values. A characteristic feature of the proposed fuzzy optimization approach is that the forecast hourly load and wind speed errors can be taken into account using fuzzy sets. Fuzzy set notations in the load demand, wind speed, voltage deviation on the secondary bus, reactive power flow through the main transformer and total real power loss on feeders are developed to obtain the optimal dispatching schedule under an uncertain environment. To demonstrate the effectiveness of the proposed method, the Volt/Var control problem is performed in a distribution system within the service area of Yunlin District Office of Taiwan Power Company (TPC). The results show that a proper dispatching schedule for ULTC position and capacitor switching operation can be reached using the proposed method.     

基于DSP的不平衡补偿和单纯形优化的静止无功补偿器

针对静止无功补偿器SVC(Static Var Compensatot)作为不平衡负荷补偿和电压稳定控制的工况,提出了不平衡补偿和优化控制方法.对于不平衡负荷补偿,提出基于虚拟对称三相系统的同步参考旋转坐标变换的补偿电纳计算方法,利用电网电压中的一相电压构造虚拟的对称三相系统,由此可以准确计算所需的补偿电纳,该方法计算简单,基于该方法的静止无功补偿器不需要硬件锁相环,能够快速、准确地补偿负荷的无功功率;对于电压稳定控制策略,提出了基于改进的单纯形加速算法SPX(SimPleX method)优化递推积分PI控制方法,以ITAE准则作为寻优目标函数,对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,能快速、无超调地跟踪SVC系统的电压设定值.仿真和实验结果表明所提不平衡补偿和优化控制方法的可行性和有效性.     

无功和谐波补偿装置的控制方法

针对具有功率因数补偿、补偿负载不平衡和滤除电网谐波电流等功能的联合运行系统,提出一种新的控制方法,由SVC模式控制和APF控制2部分组成.其中,SVC模式控制通过负序基波提取器实现电网负序基波分量的检测;通过改进的电压控制器实现公共连接点的电压稳定.利用特定次数谐波检测并进行相位补偿的方法实现电网谐波分量的检测;利用神...     

基于RTDS的TCR_TSC型SVC动态仿真模型

静止无功补偿器（SVC）系统是目前世界上柔性交流电输电系统发展的一个重要方向,具有增加输电网络的传输容量,提高输电网络运行稳定性等优点,相对传统的无功补偿方法更具有实时性和精确性。通过实时数字仿真器RTDS建立电网模型,仿真计算了静止无功补偿器（SVC）对系统故障、无功负荷波动等引起的电压波动值。结果显示,SVC能够快速跟踪电压变化量,平滑迅速地调整无功输出,有效补偿电压暂态波动,迅速恢复电压稳定。     

矿热炉混合无功补偿系统优化协调控制研究

为解决矿热炉给电网中其他用户带来的电能质量问题,尤其是电压跌落和电压闪变,提出了一种由FC、SVC和STATCOM组成的混合无功补偿系统。其中FC负责低层低成本无功补偿;SVC负责跟踪补偿无功功率变化,改善三相不平衡;STATCOM则通过快速响应来补偿SVC由于响应速度慢而导致的补偿误差,从而提高整个混合补偿系统的补偿精度。三者通过系统规则判断进行协调控制。对混合无功补偿系统进行仿真试验,分析对比了系统投入前后的电压波形,证明其补偿效果等效于等容量的STATCOM。     

有载调压变压器对系统中长期电压稳定性影响的仿真研究

应用电力系统中长期动态仿真软件Eurostag仿真研究有载调压变压器在系统不同的负荷特性下对中长期电压稳定性的影响。仿真分析表明, 有载调压变压器表现出“正调压效应”还是“负调压效应”主要取决于系统低压侧的负荷特性, 当系统重负荷且电压已经接近极限时, 对电压灵敏度高的负荷特性, 典型的是恒阻抗负荷, 有载调压变压器容易表现出“负调压效应”, 对系统电压稳定很不利; 受有载调压变压器调压影响不大的负荷特性, 典型的是恒功率负荷, 有载调压变压器对系统中长期电压稳定相当有利, 表现出很好的“正调压效应”。系统中有动态负荷时, 有载调压变压器容易表现出“负调压效应”, 但表现的程度受有载调压变压器的调压档距和容量的影响, 并且表现的方式也和静态负荷特性有所不同。     

基于级联有源滤波器与静止无功补偿器的综合补偿控制方案

级联多电平有源滤波器(CS-APF)与静止无功补偿器(SVC)同时运行存在稳定性及无功补偿控制优化等问题。文中提出一种统一控制策略,结合SVC和CS-APF的功能特点,使SVC对负载正序无功分量及负序分量的补偿进行前馈控制和电网电纳(不包含CS-APF分量)反馈控制;CS-APF对晶闸管相控电抗器(TCR)与电网负载谐波的补偿进行前馈控制,并去除SVC中固定电容分量,进行电网电流反馈控制,同时对SVC无功补偿进行二次优化补偿。另外,提出一种TCR谐波电流预计算方法,根据TCR触发角当前值与电网电压锁相环相位,构建TCR谐波电流,实现对TCR谐波的预计算。仿真和实验研究表明,在该综合控制方案下,SVC与CS-APF控制不存在闭环,系统稳定性高,TCR谐波补偿无滞后,无功补偿响应较快,补偿能力强。     

Voltage control capability of SVC with var dispatch and slope setting

Voltage control capability of SVCs is decided by their var reserves, regulation slopes and available margins. In this paper, a sensitivity model for var dispatch is proposed to restore the var reserve of SVC while keeping desirable voltage profile, and the control capability of SVCs is defined by the available control margin, the slopes, the reference voltage, the static voltage characteristic of the system. The susceptance increment for expected compensation is found to define the critical SVC possibly violating the control limit, and coordinate outputs of SVCs at different locations.     

基于DFIG与SVC的风电场无功电压协调控制策略

针对风电场的无功电压问题,构建了风电场模型,提出了一种综合考虑双馈风电机组（doubly-fed induction generator,DFIG）和静止无功补偿器（static var compensator,SVC）的无功电压协调控制策略。建立了综合考虑风电场公共接入点（point of common coupling,PCC）的电压偏移量和无功源的无功裕度的目标函数。基于混沌量子粒子群算法对风电场进行无功电压控制,通过协调DFIG和SVC的无功出力,使得风电场PCC的电压满足要求,同时提高其无功源的无功裕度。最后,以华北某风电场为例进行算例分析,验证了所提无功电压协调控制策略的可行性及有效性。     

考虑控制交互影响的变电站无功补偿系统改造

控制交互作用对整个控制系统的性能影响是致命的,因此控制器的设计及其协调在现代电力系统应用研究中是一个重要课题。文章结合目前在国内外技术上应用较成熟的静止无功补偿器(SVC)技术,提出一种与变电站综合自动化系统配合的变电站无功补偿系统改造方案,采用区域无功电压优化控制系统(AVC)统一对操作站的无功补偿设备(FC-TCR型SVC)进行无功电压优化控制,使其能统一接入变电站综合自动化系统,克服了以往变电站中无功补偿系统只能单独通过控制器的控制策略孤立运行及控制器间交互影响的问题。最后通过仿真验证了提出的方案及控制策略的可行性,仿真显示系统具有良好的动静态性能。     

Controlling chaos and voltage collapse using an ANFIS-based composite controller-static var compensator in power systems

Chaos and voltage collapse exist in power systems due to critical loading and disturbing of energy (DE). These phenomena cause instability in power system operation and must be avoided. In this paper, an ANFIS-based composite controller-static var compensator (CC-SVC) was proposed to control both chaotic oscillations and voltage collapse. The ANFIS-based CC-SVC was proposed because its computation was more efficient than Mamdani fuzzy logic controller. Adaptive network parameters were obtained through a training process. The controller parameters were automatically updated by off-line training. Both chaos and voltage collapse were able to control and suppress effectively by the proposed method. Furthermore, the load voltage was held to a set value by adjusting the supplied reactive power. When the reactive load was increased, the SVC susceptance and reactive power supplied by the SVC also increased. The proposed method was able to maintain the load voltage and to increase the loading margin.     

基于两阶段规划法的有源配电网综合电压优化控制

针对目前有源配电网调压对象单一且分布式电源(DG)和传统调压手段协调性差的问题,提出了一种基于两阶段规划的有源配电网综合调压方法。首先,通过第2阶段确定分接头位置和电容器投入组数的状态,并由差分进化算法确定第1阶段各个时段内各DG的最佳有功和无功输出。然后,将第1阶段的DG最佳输出反馈给第2阶段,再根据动态规划(DP)算法确定次日最优的电压控制预案。MATLAB仿真算例表明,与传统调压法相比,所提的两阶段规划法可更好地协调DG的出力。     

A compact control algorithm for reactive power compensation and load balancing with static Var compensator

A compact control algorithm for reactive power compensation and load balancing with the static Var compensator (SVC) in three-phase three-wire systems is developed in this paper. The required compensation susceptance of each SVC phase can be obtained from a very simple function of voltage and power signals which are measured by a three-phase voltage transducer and two single-phase active and reactive power (P–Q) transducers at the load bus. The calculation of compensation susceptances is based on the criterion of a unity power factor and zero negative-sequence currents after compensation. A simulation is made, as the first stage, to show the validity of the proposed compensation algorithm. Then, a laboratory size microcomputer-based SVC, which consists of thyristor-controlled reactors (TCRs) and fixed capacitors (FCs), is designed and implemented. Simulation and experiment results show that the algorithm is very suitable for on-line control of the SVC which is designed for phase balancing and power factor correction.     

优化有载调压变压器改善电压稳定性的新算法

为研究高电压等级电力系统互联电网中有效的电压稳定预防控制方案,讨论了超高压/高压(EHV/HV)之间有载调压变压器(OLTC)的调整在预防控制中对电压稳定的影响,提出了一种通过优化调整OLTC分接头变比改善电压稳定性的新算法。首先从当前运行点出发,利用连续潮流法计算负荷裕度,然后计算负荷裕度对分接头变比的灵敏度,利用梯度映射原理,寻找分接头变比调整的最优方向和档距,提高负荷裕度的最大值,从而改善系统的电压稳定性。仿真计算一个示例系统的结果表明:通过优化OLTC分接头变比,可明显增加系统的负荷裕度,达到电压稳定预防控制的目的。证明了该算法的可行性和有效性。