基于SMES相量模型抑制电力系统的功率振荡分析

根据超导储能装置（SMES）的工作原理,结合其结构特点与电路拓扑的发展趋势,建立了电压源型SMES相量模型。该模型将SMES等效为三相可控电流源,实现有功电流和无功电流独立控制,模拟SMES的功率响应特性,在功能上实现了对系统功率需求的准确跟踪,快速补偿系统的不平衡功率。最后,通过一个算例验证了SMES抑制单机无穷大系统功率振荡的效果,仿真结果表明该电压源型SMES可有效抑制系统的功率振荡,并使系统迅速恢复稳定运行状态,从而大大提高了系统的稳定性。     

一种新型的电流源型变流器PWM控制策略及其在超导磁储能装置中的应用

超导磁储磁能(SMES)装置的超导磁体通过变流器与电网连接,为了减小装置向系统注入的谐波电流,各种改进的脉宽调制(PWM)技术被用于变流器的控制。该文分别用正弦波和三角波作为调制和载波信号,提出一种可用于电流源型变流器的实时电流控制的新型PWM开关策略,并在此基础上研究了能够按照系统要求对电流源型SMES独立地进行有功和无功功率四象限调节的实时功率控制方法。仿真结果表明,该开关策略不仅能够快速改变变流器交流侧电流的幅值和相位,有效降低变流器交流侧电流中的谐波含量,而且能够提高SMES装置的功率响应特性。同时该方法还具有控制策略简单,工程实现容易的特点。     

基于混合高温超导储能系统的电网动态功率补偿策略与试验

为实现高温超导储能系统(SMES)对电网功率波动的动态补偿,采用第1代铋系和第2代钇钡铜氧高温超导材料,设计并构建了过冷液氮温区运行、千焦级容量的混合高温超导储能系统。应用数字信号处理器和微控制器的双处理器形式,设计了LCL滤波的电压型SMES变流器的功率控制系统电路,基于空间矢量脉冲调制法(SVPWM),提出了SMES变流器对系统功率补偿的控制方法,并进行控制软件编程,实现对并网侧功率的动态监测和补偿策略的实时计算。最后应用SMES在一条200km输电线路上进行并网动模试验,针对电网负荷变化产生的功率波动状态,实现了毫秒级内对电力系统的快速功率输出和波动抑制,验证了超导储能系统对电网瞬时功率补偿策略和功率补偿变流装置的有效性。     

超导磁储能装置在风电系统控制中的应用

超导磁储能装置(SMES)是将超导技术、电力电子技术、控制理论和能量管理技术相结合的一种新型储能装置。在实时补偿系统中,由于各种原因会产生不平衡功率,SMES从这一新的角度出发考虑提高电力系统稳定性的问题。理论研究表明,SMES是一种提高电力系统稳定性的非常有效的新措施。为促使这一理论的广泛应用,同时进一步提高SMES的可靠性,研究将超导磁储能装置应用于风电场,以稳定系统输出;在此基础上,对风电场中超导磁储能装置的信号选取和控制策略等关键技术进行研究,阐述了未来的发展趋势。     

基于平衡补偿法对负载中性点偏移电压的测量

配电系统中一般已知三相电压以及三相功率潮流,不能测出负载端中性点偏移电压,而在建立并求解三相电源电流数学模型的前提是必须已知中性点偏移电压。介绍了一种根据平衡补偿法测量中性点电压偏移量,应用并联补偿装置对不对称负载进行平衡补偿,得出补偿后系统对称电流和对称阻抗。采用不对称负载和补偿电抗的星三角变换对不对称负载进行修正,依据补偿前不对称电流等于负载电流为条件重复迭代计算精确求出不对称负载,并求得中性点电压偏移量。最后依据广东某一变电站为例,计算并用Matlab仿真证明了该方法的正确性。     

基于超导储能的瞬时电压跌落补偿

超导储能(SMES)是解决瞬时电压跌落问题的一种很有前途的方案。由于SMES自身的特点,基于SMES的瞬时电压跌落补偿装置在主电路结构、参数设计、补偿原理和控制方法上均不同于传统的动态电压恢复器。为了保护一个110kVA的重要负载不受瞬时电压跌落的危害,一套基于SMES的瞬时电压跌落补偿系统正在开发中。该系统主要由0．3MJ超导线圈、200kVA绝缘栅双极晶体管(IGBT)电流型变流器和2．5mH移相电抗器组成。文中通过理论分析和仿真计算介绍了系统主电路的工作原理及参数设计。为实现瞬时控制和获得更高的响应速度,采用了直接电流脉宽调制(PWM)开关策略。开环仿真结果表明,系统可以满足瞬时电压跌落的补偿要求。     

超导储能装置对输电线路纵联电流差动保护的影响分析

由于超导储能(SMES)装置的功率调节系统能够在四象限内快速、独立地向系统提供有功功率和无功功率,因此,其动作特性可能会对现有输电线路纵联电流差动保护装置动作产生影响.文中通过建立含有SMES装置的双电源输电系统的电磁暂态模型,在实现SMES装置抑制发电机机端功率振荡的基础上计算分析了SMES系统动作特性对纵联电流差动保护的影响.仿真计算结果表明,SMES装置能够很好地抑制发电机机端功率振荡,且对现有的纵联电流差动保护的动作结果不会产生影响.     

SMES抑制电力系统功率振荡的控制策略研究

为实现超导磁储能装置(superconducting magnetic energy storage,SMES)对电力系统功率的准确跟踪与快速补偿,并有效抑制系统的功率振荡,首先分析了包含SMES的单机系统的功角特性,基于系统的能量函数,以提高系统阻尼为目标,提出了以SMES接入点电压及其变化率为控制变量的导纳控制方法数学模型。与传统的以接入点电压幅值或相角做控制变量的控制方法不同,导纳控制方法不仅与接入点电压幅值有关,还与其变化速度有关,因而可提高SMES响应的灵敏度和精度。最后,通过算例验证了SMES抑制单机无穷大系统功率振荡的效果,结果表明该控制方法不仅可以有效抑制功率振荡,而且能使系统迅速恢复稳定状态,从而能提高电力系统的运行稳定性。     

三电平不平衡负载补偿装置直流侧电压控制

在三相不平衡治理装置中,需要输出负序电流和零序电流来实现对不平衡负载的补偿。以三电平电能质量智能补偿装置为依托,从功率守恒的角度揭示了补偿正序、负序、零序电流时输出电流与直流侧电压的内在关系,同时根据不同应用场合建立电压控制的不同控制策略,实现逆变器直流电压和输出电流的精准控制,并借助实体样机进行验证。     

150kVA/0.3MJ电流源型动态电压补偿装置

为保护110 kW负载不受瞬时电压跌落的影响,研制了一套150 kVA/0.3 MJ基于超导储能(SMES)的动态电压补偿(Dynamic Voltage Restorer,简称DVR)装置.该装置主要包括150 kVA的IGBT电流源型变流器、0.3 MJ NbTi超导储能磁体和2.5 mH三相移相电抗器.为了检验装置的补偿性能,在模拟电源电压三相对称跌落和单相跌落的情况下,以110 kW的三相电阻为负载进行了实验验证.实验结果表明,当电源发生对称或不对称瞬时电压跌落时,负载电压能够在一个工频周期(20 ms)内被补偿至额定值.     

Design and modeling of SMES based SAPF for pulsed power load demands

In this article, a Superconducting Magnetic Energy Storage (SMES) based Shunt Active Power Filter (SAPF) topology is proposed to compensate high power pulsating load demands in a power system. The SMES based SAPF is designed and modeled to realize as an efficient compensator for the compensation of pulsed power load demands. The conventional SAPF is efficient to mitigate the power quality problems in a power system unless there is high power pulsating load demands, transient conditions or power fluctuations. Particularly, a Modified Synchronous Reference Frame (MSRF) control algorithm has been implemented to generate proper switching signals for the three-phase Voltage Source Converter (VSC) of the SMES based SAPF. In the simulation, it has been seen that the SAPF is incompetent under high power pulsating load demands whereas the SMES based SAPF has shown excellent performance under such load conditions. Moreover, a comparative analysis has been made between the conventional SAPF and the SMES based SAPF under pulsating load conditions, to check the effectiveness of the SMES based SAPF. The performance of the proposed system is presented by using Sim Power System (SPS)/MATLAB Simulink and real-time digital simulator laboratory (RTDS-Lab).     

超导储能装置用于改善暂态电压稳定性的研究

建立了超导储能装置(SMES)在暂态电压稳定性分析中的简化数学模型.SMES经双桥系统的电流源型换流电路与电力系统相连.研究了具有快速响应特性的SMES在提高电力系统暂态电压稳定性方面的作用和其无功控制策略,以及采用不等触发角控制时的控制原则.在Matlab平台上编制了暂态仿真程序,对典型3机10母线系统进行了仿真计算.仿真结果表明,超导储能装置安装在动态负荷处,采用无功-电压控制方式能够有效地提高系统的暂态电压稳定性.     

Superconducting magnetic energy storage controller design and stability analysis for a power system with various load characteristics

A simultaneous active power and reactive power (P–Q) control scheme of superconducting magnetic energy storage (SMES) unit is proposed to enhance the damping of a power system. In order to control the P–Q modulation to the power system, a proportional-integral (PI) controller is used to provide a supplementary damping signal. The parameters of the PI controller are determined by a systematic pole assignment method based on modal control theory. Both static load and dynamic load are included to improve the system model fidelity. Eigenvalue analysis and time-domain nonlinear simulation, using a power system incorporating a composite load, are illustrated to validate the effectiveness of the proposed PI SMES controller for the damping of the studied system over a wide range of operating conditions. The control scheme also shows that the stability margin of the power system is expanded.     

A fuzzy logic controlled superconducting magnetic energy storage,SMES frequency stabilizer

This paper presents application of fuzzy logic controlled superconducting magnetic energy storage device, SMES to damp the frequency oscillations of interconnected two-area power systems due to load excursions. The system frequency oscillations appear due to load disturbance. To stabilize the system frequency oscillations, the active power can be controlled via superconducting magnetic energy storage device, SMES. The error in the area control and its rate of change is used as controller input signals to the proposed fuzzy logic controller. In order to judge the effect of the proposed fuzzy logic controlled SMES, a comparative study is made between its effect and the effect of the conventional proportional plus integral (PI) controlled SMES. The studied system consists of two-area (thermal–thermal) power system each one equipped with SMES unit. The time simulation results indicate the superiority of the proposed fuzzy logic controlled SMES over the conventional PI SMES in damping the system oscillations and reach quickly to zero frequency deviation. The system is modeled and solved by using MATLAB software.     

Integration of PV system with SMES based on model predictive control for utility grid reliability improvement.

This paper describes the integration of a photovoltaic (PV) renewable energy source with a superconducting magnetic energy storage (SMES) system. The integrated system can improve the voltage stability of the utility grid and achieve power leveling. The control schemes employ model predictive control (MPC), which has gained significant attention in recent years because of its advantages such as fast response and simple implementation. The PV system provides maximum power at various irradiation levels using the incremental conductance technique (INC). The interfaced grid side converter of the SMES can control the grid voltage by regulating its injected reactive power to the grid, while the charge and discharge operation of the SMES coil can be managed by the system operator to inject/absorb active power to/from the grid to achieve the power leveling strategy. Simulation results based on MATLAB/Simulink® software prove the fast response of the system control objectives in tracking the setpoints at different loading scenarios and PV irradiance levels, while the SMES injects/absorbs active and reactive power to/from the grid during various events to improve the voltage response and achieve power leveling strategy.     

Comparative performance evaluation of SMES-SMES, TCPS-SMES and SSSC-SMES controllers in automatic generation control for a two-area hydro-hydro system

This paper presents the automatic generation control (AGC) of an interconnected two-area multiple-unit hydro-hydro system. As an interconnected power system is subjected to load disturbances with changing frequency in the vicinity of the inter-area oscillation mode, system frequency may be severely disturbed and oscillating. To compensate for such load disturbances and stabilize the area frequency oscillations, the dynamic power flow control of static synchronous series compensator (SSSC) or Thyristor Controlled Phase Shifters (TCPS) in coordination with superconducting magnetic energy storage (SMES) are proposed. SMES-SMES coordination is also studied for the same. The effectiveness of proposed frequency controllers are guaranteed by analyzing the transient performance of the system with varying load patterns, different system parameters and in the event of temporary/permanent tie-line outage. Gains of the integral controllers and parameters of SSSC, TCPS and SMES are optimized with an improved version of particle swarm optimization, called as craziness-based particle swarm optimization (CRPSO) developed by the authors. The performance of CRPSO is compared to that of real coded genetic algorithm (RGA) to establish its optimization superiority.     

超导储能用电压型大功率换流器技术

在500 kVA超导储能系统研制中,为了选择合适的功率变换电路拓扑,使系统具有更高的电压等级和灵活性,比较了近年来国内外采用的几种电压型换流器。针对超导储能特点及其在电力系统中承担电能质量调节的要求,分析了传统2电平桥式换流电路、中点钳位型多电平换流电路以及级联型多电平换流电路的性能。分析结果表明,对于大功率超导储能装置,级联型多电平换流电路在电压等级、控制精度及结构灵活等方面均优于另外2种换流器拓扑,采用级联型换流器的超导储能系统实现了模块化构造,可以实现系统冗余及容错运行。仿真结果证实模块化超导储能系统能够在较低工作频率下精确控制电压质量。     

超导磁储能系统抑制风力发电功率波动的研究

建立含超导磁储能装置(SMES)的单机无穷大系统的Phillips-Heffron模型,导出含SMES电力系统总的电磁转矩表达式,从理论上分析SMES对增强系统阻尼的作用.并设计了SMES非线性比例积分微分控制器,数字仿真结果验证了SMES阻尼系统功率振荡的特性,同时表明该控制器具有较好的鲁棒性.     

Design of a coordinated robust controller of SMES and blade pitch for smart‐grid power systems

This paper presents the design of a coordinated superconducting magnetic energy storage (SMES) and blade pitch controller (BPC) to stabilize the frequency in a smart‐grid power system. To compensate for such power variations, a SMES that is able to supply and absorb active power quickly can be applied to control the frequency fluctuation. The structure of the controller is that of a first‐order lead–lag compensator. The robustness of the controller is guaranteed by applying an inverse additive perturbation to represent possible unstructured uncertainties in the power system such as variation of system parameters, generating and loading conditions, etc. Genetic algorithm (GA) is applied to solve and achieve the control parameters. Simulation studies have been done to show the control effect and robustness of the proposed SMES and blade pitch in comparison with SMES & Pitch against various disturbances. © 2012 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.