Features of A New 500 kVAR Static VAR Generator

The paper briefly describes the main features of a new 500 kVAR static VAR generator designed and manufactured by NAm for industrial test and trial

Research on resonance fault caused by dc magnetic biasing in ultra high voltage transformer with parallel static var compensator

For dealing with the resonance fault of ultra-high voltage transformers(UHVTs)with the parallel thyristor controlled reactor(TCR)+the filter compensator(FC)type static var compensator(SVC)caused by dc magnetic biasing,a simulation model of UHVT with parallel SVC for the frequency analysis of the impedance characteristics and a magnetic-field coupling model for UHVT based on classic Jiles-Atherton hysteresis theories are constructed based on the MATLAB/Simulink platform.Both the theoretical and simulation results prove that the resonance fault is caused by the resonance point on the low-voltage side of the transformer,which will approach the 4th harmonic point under magnetic biasing.Based on the fault analysis,a new resonance control method is proposed by adding reactance with by-pass switches in series with FC branches.Under dc magnetic biasing,the cutoff of the by-pass switch will increase the series reactance rate of the FC branches and change the resonance point.In order to avoid the 7th harmonic increasement caused by this method,the firing angle of the TCR branches is locked between 130°and 180°.The effect of the proposed method is validated by the simulation model of a 750 kV UHVT and the results show that the mechanism analysis of the resonance fault is correct and the resonance control method is valid.

Parameter Identification for Static Var Compensator Model Using Sensitivity Analysis and Improved Whale Optimization Algorithm

A parameter estimation method based on an improved Whale Optimization Algorithm is proposed in this paper to identify the parameters of a static var compensator(SVC)model.First,a mathematical model of SVC is established.Then,the reverse learning strategy and Levy flight disturbance strategy are introduced to improve the whale optimization algorithm,and the improved whale optimization algorithm is applied to the parameter identification of the static var compensator model.Finally,a stepwise identification method,by analyzing the local sensitivities of parameters,is proposed which solves the problem of low accuracy caused by multi-parameter identification.This method provides a new estimation strategy for accurately identifying the parameters of the static var compensator model.Estimation results show that the parameter estimation method can be an effective tool to solve the problem of parameter identification for the SVC model.

Decentralized robust control of multiple static var compensators via Hamiltonian function method

Using the energy-based Hamiltonian function method, this paper investigates the decentralized robust nonlinear control of multiple static var compensators （SVCs） in multimachine multiload power systems. First, the uncertain nonlinear differential algebraic equation model is constructed for the power system. Then, the dissipative Hamiltonian realization of the system is completed by means of variable transformation and prefeedback control. Finally, based on the obtained dissipative Hamiltonian realization, a decentralized robust nonlinear controller is put forward. The proposed controller can effectively utilize the internal structure and the energy balance property of the power system. Simulation results verify the effectiveness of the control scheme.

Optimal Controller Design for Non-Affine Nonlinear Power Systems with Static Var Compensators for Hybrid UAVs

A generalized non-affine nonlinear power system model is presented for a single machine bus power system with a Static Var Compensator(SVC)or State Var System(SVS)for hybrid Unmanned Aerial Vehicles(UAVs).The model is constructed by differential algebraic equations on the MATLAB-Simulink platform with the programming technique of its S-Function.Combining the inverse system method and the Linear Quadratic Regulation(LQR),an optimized SVC controller is designed.The simulations under three fault conditions show that the proposed controller can effectively improve the power system transient performance.

含静止无功发生器的直驱风电并网系统稳定性分析及振荡抑制策略

风电并网系统稳定性分析及振荡抑制策略大多集中于风电场本身,针对含静止无功发生器(SVG)的直驱风电并网系统研究较少。基于特征值灵敏度筛选出对含SVG的直驱风电并网系统稳定性较显著的控制通道,然后基于独立通道分析设计理论将并网系统由多输入多输出耦合系统等效拆分为多个单输入单输出控制通道,在定性分析并网系统稳定性的同时定量评估不同控制通道间的交互作用程度。为抑制控制通道间的交互作用,提出了基于H∞鲁棒控制的次同步振荡抑制策略。通过电磁暂态仿真,验证了基于独立通道分析设计理论分析并网系统稳定性的正确性以及基于H∞鲁棒控制的次同步振荡抑制策略的有效性。

分布式光伏配电网电压无功优化研究

为解决分布式光伏接入配电网引起的电压越限质量问题,建立以有功网损和电压偏差最小为目标的无功优化数学模型。通过对光伏并网点的电压进行分析,提出了一种加权方式的电压功率与静止无功发生器控制补偿相结合的协同控制策略。为提高模型的求解能力,采用改进的粒子群优化算法,引入变异操作防止算法陷入局部最优;为提高算法的收敛效果,采用改进的异步学习因子。在IEEE-33节点配电系统中进行算例验证,结果表明了模型的正确性和策略的有效性。

补偿不平衡负载的HC-SVG相间电压平衡控制与直流电压取值分析

针对由中点钳位型(neutral-point clamped,NPC)功率单元和H桥级联型(cascade H-bridge,CHB)功率单元构成的混合级联型静止无功发生器(hybrid cascade static var generator,HC-SVG)在补偿不平衡负载时产生的CHB功率单元相间电压失衡问题,提出一种基于零序电压前馈的CHB功率单元相间电压平衡控制方法,并对零序电压注入后HC-SVG直流侧电压取值进行分析。首先,分析CHB功率单元承担基波电压分量与HC-SVG输出基波电压的关系。推导HC-SVG补偿不平衡负载时CHB功率单元相间电压平衡所需的零序电压,建立零序电压前馈控制。其次,基于零序电压与补偿电流的解析关系,讨论补偿电流不平衡度与HC-SVG直流侧电压取值之间的约束关系。以6 kV/3 Mvar装置为算例,进行直流侧电压的取值分析。并与星接CHB-SVG进行对比,揭示补偿不平衡负载时HC-SVG所需直流电压低的特点。仿真验证了相间电压平衡控制与直流电压取值分析的有效性。

基于改进TS模糊的直流电弧炉闪变抑制优化

为提高静止无功补偿器(static var compensator,SVC)应对直流电弧炉等冲击性负载的闪变抑制性能,文中在改进Takagi-Sugeno(TS)模糊算法的基础上,提出一种SVC滚动预测控制方法。首先,建立直流电弧炉电气模型并仿真分析其无功特性;然后,针对经典TS模糊预测算法应用于波动负荷时出现的输出异常置0情况,提出一种范围自适应修正的改进方法,该方法能消除一类算法应用机理导致的异常值,从而提高TS模糊算法对波动负荷无功功率预测的可靠性和准确性;最后,基于模型训练时间约束,建立无功功率半周期滚动预测控制模型,提前10 ms预测无功功率,改善了SVC传统控制系统响应的滞后特性。仿真结果表明,相比于SVC传统控制方法,所提方法的平均闪变改善率提高了54.17%,验证了所提方法对闪变现象的抑制效果提升显著。

基于静止无功发生器的双流制牵引供电系统控制策略

基于静止无功发生器的双流制牵引供电系统可用于交直流供电系统并存的供电区段,也能为多制式机车提供出厂试验,减少供电设备,提高效率,并解决以负序为主的电能质量问题。提出双流制供电系统的结构,根据负荷的运行工况分别研究2种运行方式的基本原理,构建负序补偿数学模型并推导静止无功发生器容量的计算式。基于瞬时无功理论,研究该方案中静止无功发生器的控制策略。搭建仿真模型,仿真结果表明在不同的负荷运行工况下,双流制供电系统既能为交流负荷和直流负荷提供运行功率,也能对公共连接点处的负序进行治理,验证了补偿方案的正确性与可行性。

基于静止无功发生器详细模型的机电暂态仿真适应性分析

机电暂态仿真是大电网分析的重要工具。现有电力电子设备的机电暂态模型一般呈现理想电流源特性,无法体现设备自身稳定性及能力约束对于系统暂态特性的影响。在电力电子化电力系统背景下,以上不足降低了仿真准确性,制约了电网运行极限制定与新能源送出能力。文中基于旋转坐标系推导了静止无功发生器及控制系统的标幺化数学模型,并建立了对应的机电暂态模型。在建模精度与电磁暂态模型一致的前提下,通过模态分析法对比了机电暂态仿真与电磁暂态仿真的主要差异,揭示了机电暂态仿真的能力边界与适用范围。结果表明,机电暂态仿真能够揭示与工频能量流有关的功角、频率、电压稳定特性,而不能反映与电网动态强相关的谐振或者宽频振荡特性。

集无功和谐波补偿功能于一体的构网型变流器研发

为了解决大规模风电并网面临的电压越限、谐波谐振、主动支撑能力变差等问题,充分利用电力电子变换装置灵活可控的优势,研发了一种集静止无功发生器(SVG)和有源滤波器(APF)功能于一体的构网型变流器。类比直流母线电容的充放电特性和同步发电机转子的加减速特性,设计有功控制环,在不引入锁相环的情况下实现电网相位跟随、谐振风险降低;基于无功-电压下垂控制原理,设计无功控制环,实现无功补偿和电压支撑;通过谐波电流检测和内环电流控制,实现负载谐波电流补偿。最后,搭建基于RT-Box的硬件在环实验平台,对所提构网型变流器的多重功能进行验证。结果表明,并联设计的集静止无功发生器和有源滤波器功能于一体的构网型变流器可大大改善电网谐波、功率因数,提高电力系统的电能质量。

20 Mvar静止无功发生器(SVG)控制器的设计

介绍２０ Ｍｖａｒ 静止无功发生器的控制器设计，包括硬件结构、控制策略等。该装置基于ＤＳＰ开发，采用瞬时电量定义及精心选择的各类高速数字芯片，加速了数据采集和处理。动模试验证明该控制器的高可靠性、高脉冲精度，具有一定的通用性。

抑制新能源次/超同步振荡的SVG鲁棒自适应控制参数设计方法

现有抑制新能源次/超同步振荡的静止无功发生器(SVG)控制设计方法大多针对单一运行场景,难以确保运行工况变化下系统的小干扰鲁棒稳定性。为此,提出了一种抑制新能源次/超同步振荡的SVG鲁棒自适应控制参数设计方法。论证了短路比(SCR)可用于评估运行工况变化下含SVG的新能源并网系统小干扰稳定裕度;基于短路比分析方法,发现了代表系统小干扰稳定性最差的关键运行工况;基于H_(∞)控制理论,提出了一种关键运行工况下SVG控制参数鲁棒自适应设计方法。该方法能确保含SVG的新能源并网系统在运行工况变化下系统的小干扰鲁棒稳定性。

基于 IGBT 的 1MVAR 无功发生器的设计与实验

本文描述了基于ＩＧＢＴ的１ＭＶＡＲＡＳＶＧ装置的主电路结构、工作原理、控制系统及驱动和检测电路的设计，并就其对电力系统造成的谐波影响进行分析。

基于LADRC的双馈风机与SVG协调控制的并网系统研究

为了解决双馈风机(doubly fed induction generator,DFIG)在并网或运行时给电网带来的稳定性问题,提出了静止无功发生器(static var generator,SVG)与DFIG协同补偿无功的方法,并在此基础上通过线性自抗扰控制(linear active disturbance rejection control,LADRC)代替传统的PI控制来控制变流器,以及加装超级电容储能对DFIG的变流器直流侧控制进行优化。最后结合风电场的实际情况,在MATLAB中搭建了使用LADRC的含超级电容的双馈风机并网模型,并对其并网时的交直流波动以及无功功率的传输进行了仿真分析,实验结果验证了该控制策略可以提高双馈风机稳定运行的能力,解决功率波动时变流器交直流侧功率不平衡的问题,与SVG的协同控制策略可以提高系统的低电压穿越能力,提高了整个风力发电系统的稳定性。

Comparative study of effectiveness of different var compensation devices in large-scale power networks

A comparison of the effectiveness of installing reactive power compensators,such as shunt capacitors,static var compensators(SVCs),and static synchronous compensators(STATCOMs),was presented in large-scale power networks.A suitable bus was first identified using modal analysis method.The single shunt capacitor,single SVC,and single STATCOM were installed separately on the most critical bus.The effects of the installation of different devices on power loss reduction,voltage profile improvement,and voltage stability margin enhancement were examined and compared for 57-and 118-bus transmission systems.The comparative study results show that SVC,and STATCOM are expensive compared to shunt capacitor,yet the effect of installing STATCOM is better than SVC and the effect of installing SVC is better than that of shunt capacitor in achieving power loss reduction,voltage profile improvement and voltage stability margin enhancement.

基于小型SVG电气柜的散热分析

为了满足各种控制需要,利用静止无功补偿电气柜实现高度集成化、小型化,导致电气柜内部发热元件数量增加,散热空间缩小。针对发热问题,选择一种合适的散热方式,并根据产品设计要求调整优化散热方案,使温度降低至正常范围内,以解决静止无功补偿电气柜发热问题。

发电机组低负荷下的SVG无功补偿技术应用分析

低负荷运行容易导致发电机组无功功率不足、电压不稳定等问题,影响电力系统的稳定性和可靠性。探讨了在发电机组低负荷条件下应用静止无功发生器(SVG)技术进行无功补偿的途径。分析了SVG在维持电压稳定、改善功率因数以及减轻低负荷运行对发电机组的不良影响等方面的表现和有效性,并通过实验和仿真开展评估验证。

±10 Mvar/10 kV静止无功发生器链节的研究

目前,静止无功发生器(SVG)已广泛应用于风力发电、太阳能发电等新能源发电领域。根据某公司自主研制的±10 Mvar/10 kV链式SVG,其拓扑结构为H桥级联,每相由12个链节(H桥)串联而成。详细介绍了H桥级联SVG链节的研究与功能验证。通过链节的对冲试验及其结果,验证了链节的功能和对冲试验控制策略的效果,使得链节的设计符合《链式静止同步补偿器》技术标准的要求(1.1倍过载时,能够连续运行),从而确保±10 Mvar/10 kV SVG能在工程现场正常、稳定地运行。