10 kV配电网柱上开关雷击分析和防雷措施研究

配电网柱上开关设备极容易遭受雷击而出现故障, 如何提高其防雷性能对于提高供电可靠性具有重要意义。分析了配电网柱上开关设备遭受雷击的特点,阐述了雷击配电网柱上开关设备的机理及其对整个配电网的危害情况。提出了柱上开关设备防雷的技术措施。     

链式STATCOM直流侧电压平衡控制策略研究

针对STATCOM电容直流电压不稳定问题进行了分析,提出了一种增加附加充放电电路方式的STATCOM电容电压控制策略。采用附加电路对链式STATCOM电容进行充电及稳压控制,其中附加电路多绕组变压器的使用,有效地隔离了附加电路各链节直接的电的联系,消除了附加电路和装置主电路同时投入时电压瞬时降为零的现象,使得附加电路的控制策略可以完全和主电路控制策略独立;附加电路既可以直接接到大电网中,也可以采用与电网分离的独立供电电源,甚至可以采用大容量的UPS,可以较好地实现装置启动、快速功率切换等。装置动态响应能力亦有所增强,同时当主电路出现较大电压波动时,仍可以保证STATCOM电容电压的稳定,正常地输出无功。     

一种用于三相PFC，APF和STATCOM的通用矢量控制器

功率因数校正器（PFC）．有源滤波器（APF）和静止同步补偿器（STATCOM）是输配电系统中不可缺少的器件。理论和实验表明单周期控制策略控制三相PFC,APF和STATCOM,性能良好,电路结构简单,成本低。本文通过回顾PFC,APF和STATCOM单周期控制下的关键控制方程及电路,提出了一种通用控制电路,进一步研究表明该控制电路可以方便植入一种芯片控制所有的变换器。最后,通过实验和仿真结果证实了该理论的正确性。     

基于不同失稳机理的动态无功补偿装置的配置

从输电网功角失稳和配电网电压失稳的不同机理出发,对动态无功补偿装置在输、配电网络中不同配置进行了探索性的分析.对于输电网,根据系统失稳时临界割集处电压降低幅度大的特点,提出在输电网的临界割集或附近安装STATCOM装置,其原因在于STATCOM装置受端电压变化影响小,在功角失稳前电压降得很低时仍能提供较大感性无功功率;...     

Pole placement by coordinated tuning of Power System Stabilizers and FACTS-POD stabilizers

This work presents the application of the Decentralized Modal Control method for pole placement in multimachine power systems utilizing FACTS (Flexible AC Transmission Systems), STATCOM (Static Synchronous Compensator) and UPFC (Unified Power Flow Controller) devices. For this, these devices are equipped with supplementary damping controllers, denominated POD (Power Oscillation Damping), achieving a coordinated project with local controllers (Power System Stabilizers - PSS). Comparative analysis on the function of damping of the FACTS, STATCOM and UPFC is performed using the New England System that has 10 generators, 39 buses and 46 transmission lines.     

Coordinated design of STATCOM and excitation system controllers for multi-machine power systems using zero dynamics method

FACTs devices are being used in transmission networks for increasing the power transfer limit and stability improvement. They also help damp out both local and inter-area low frequency oscillations. However, uncoordinated design of these devices with excitation systems may deteriorate the power system performance. Moreover, power system is a large, complex and nonlinear system, and the controllers that are designed based on linear control theories may have a detrimental effect on the system performance, especially when there are large disturbances occurring in the system. The design method of a nonlinear control technique, named zero dynamics is given in this paper to design the controllers of STATCOM and excitation systems coordinately for multi-machine power systems. This technique is able to provide the stability of both external and internal dynamic performances of the system. Simulations results clearly verify that the proposed method improves the power system stability.     

Model order reduction of coupled circuit‐device systems

We consider model order reduction of integrated circuits with semiconductor devices. Such circuits are modeled using modified nodal analysis by differential‐algebraic equations coupled with the nonlinear drift‐diffusion equations. A spatial discretization of these equations with a mixed finite element method yields a high dimensional nonlinear system of differential‐algebraic equations. Balancing‐related model reduction is used to reduce the dimension of the decoupled linear network equations, whereas the semidiscretized semiconductor model is reduced using proper orthogonal decomposition. Because the computational complexity of the reduced‐order model through the nonlinearity of the drift‐diffusion equations still depends on the number of variables of the full model, we apply the discrete empirical interpolation method to further reduce the computational complexity. We provide numerical comparisons that demonstrate the performance of the presented model reduction approach. Copyright © 2012 John Wiley & Sons, Ltd.     

Development of Automatic Voltage Regulator for Low‐Voltage Distribution Systems

This paper presents the development of a new type of voltage regulator that can adequately maintain the voltage supplied to customers, dealing with the problem of voltage control that accompanies the widespread use of photovoltaic power generation systems. The newly developed device is a pole‐mounted voltage regulator consisting of a step‐down transformer that converts from high voltage to low voltage and a series transformer for voltage compensation. A demonstration test conducted at the CRIEPI Akagi Test Center confirmed that the voltage control function of the proposed voltage regulator is satisfactory, based on the proposed control algorithm. Simulation analysis, under the assumption of clustered installation of photovoltaic power generation systems, confirmed that the introduction of the proposed voltage regulator allows the system voltage to be adequately maintained and makes full photovoltaic power generation possible without suppressing the output. We anticipate that our proposed voltage regulator will be effective for adequately regulating the voltage in low‐voltage distribution systems and will effectively promote even more widespread photovoltaic power generation.     

Application of a multivariable feedback linearization scheme for STATCOM control

This paper investigates application of a multivariable control technique to the multi-input multi-output (MIMO) nonlinear model of a static synchronous compensator (STATCOM). The proposed controller design is based on a feedback linearization scheme. Its prime goal is the coordinated control of ac and dc voltage for a STATCOM installed in a power distribution system. First, the nonlinear mathematical model of STATCOM along with the distribution system is derived. Then, by using input–output feedback linearization, a state feedback control law is obtained by pole placement. The efficacy of the control strategy is evaluated by digital computer simulations on the complete system for various types of loads and/or disturbances. The comparative study of these results with those obtained in a conventional cascade control architecture establishes the elegance of this new control scheme.     

Application of a modular multilevel cascade converter (MMCC‐SDBC) to a STATCOM. Control of active power and negative‐sequence reactive power

This paper presents the application of a modular multilevel cascade converter based on single‐delta bridge‐cells (MMCC‐SDBC) to a STATic synchronous COMpensator (STATCOM), particularly for negative‐sequence reactive‐power control. The SDBC is characterized by cascade connection of multiple single‐phase H‐bridge (or full‐bridge) converter cells per leg, which facilitates ?exible circuit design, low voltage steps, and low electromagnetic interference (EMI) emissions. However, there is no published report on such a STATCOM with experimental veri?cation or a control strategy. This paper designs, constructs, and tests a 100‐V 5‐kVA PWM STATCOM based on the SDBC with focus on the operating principle and performance. Experimental results con?rm that this converter can control not only the positive‐sequence reactive power but also the negative‐sequence reactive power and low‐frequency active power intended for the ?icker compensation of arc furnaces. © 2013 Wiley Periodicals, Inc. Electr Eng Jpn, 183(4): 33–44, 2013; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.22365     

全碳化硅大功率直流电源关键技术研究

碳化硅SiC(silicon carbide)功率器件的耐压、频率和损耗等特性均优于硅(Si)器件,然而SiC器件抗冲击能力差、电磁干扰大,且SiC器件对整个功率变换系统的贡献尚缺乏分析验证,因此,采用全SiC器件研制高性能的大功率直流电源具有一定挑战.首先针对SiC器件抗冲击能力差的问题,引入嵌入式保护策略,应对直流...     

Current differential amplifiers: new circuits and applications

New CMOS current differential amplifiers are proposed suitable for analogue signal processing at high frequencies. They consist of simple current mirrors, which are easy to design and to implement in IC form. Low‐voltage low‐power design is feasible. Relying on these devices a number of applications are obtained, including lossy and lossless integrators, simulated inductors, active filters, and harmonic oscillators. Theoretical expressions are given for all of the proposed new circuits. The verification of the circuits is also achieved by simulation. Copyright 2001 © John Wiley & Sons, Ltd.     

南方电网±200 Mvar静止同步补偿装置工程实践

静止同步补偿装置(STATCOM)作为一项世界上目前最为先进的无功补偿技术,已大量应用于现代电力系统的负荷补偿,但在输电线路补偿方面的应用尚少。鉴此,介绍了南方电网±200 Mvar静止同步补偿装置的工程实践,包括该工程的设计方案和主要的技术特点,STATCOM的输出谐波、损耗、噪音等性能。南方电网在该工程的实践为大容量STATCOM装置在高压大功率输电领域的应用提供了可供借鉴的经验。     

高压直流输电系统动态恢复特性的仿真研究

为改善高压直流输电(HVDC)系统故障下的动态恢复特性,运用PSCAD/EMTDC仿真工具,研究了HVDC系统逆变站分别采用固定电容器(FC)、静止无功补偿器(SVC)、静止同步补偿器(STATCOM)3种无功补偿设备时的故障恢复特性,其中故障有直流闭锁、换流母线三相接地、单相接地、远端三相接地等。结果表明,交流系统较弱时,SVC会降低交流系统强度,而导致HVDC系统故障及故障恢复时发生连续换相失败,而STATCOM在电压保持、功率恢复等方面都较其他补偿设备有着明显的优点,能够显著改善HVDC系统的动态特性。     

静止无功发生器与晶闸管投切电容器协同运行混合无功补偿系统

提出一种低成本混合型无功补偿系统(hybrid var compensator,HVC),它由一台较小容量的静止无功发生器(static synchronous compensator,STATCOM)和较大容量的多组晶闸管投切电容器(thyristor switched capacitor,TSC)构成,其中STATCOM用以实现快速连续无功调节,TSC实现无功的大容量分级调节,二者协同工作使HVC系统兼具STATCOM快速连续无功补偿及TSC低成本大容量无功补偿的优势,实现低成本大容量的无功连续补偿。在分析HVC基本工作原理的基础上,提出基于专家决策的HVC协调控制方法,实现离散子系统TSC和连续子系统STATCOM的协调控制,确保HVC能进行快速大容量的无功补偿,针对传统的STATCOM串级电压控制器中调节器多、控制器参数难以设计的缺点,提出基于瞬时功率平衡的电压控制策略,以降低STATCOM控制复杂度,提高可靠性,使系统更易于实现。仿真及现场应用结果证明HVC能够实现无级连续无功补偿,并且成本低,在满足高电耗企业节能降耗需求的基础上,为应用单位减少了投资。     

基于配电系统的静止同步补偿器技术发展的探讨

介绍了现代配电网的发展现状,阐述了基于配电系统的静止同步补偿器(STATCOM)的结构及控制逻辑,对其损耗及谐波进行了分析。提出了STATCOM未来的发展方向是直接电压支撑及改善稳态和暂态稳定性,指出由电力电子器件所组成的变换器模块部分是主要研究方向。     

Development of High‐Power Density Interleaved dc/dc Converter with SiC Devices

We developed an interleaved dc/dc converter with SiC devices. We applied full‐SiC modules including MOSFETs and SBDs to the interleaved dc/dc converter to achieve a high‐power density. An SiC has a high temperature resistance, which facilitates an improvement in high‐frequency drives. We achieved a high‐power density by utilizing this high temperature resistance. We also fabricated a prototype and tested it with loads up to 65 kW.     

中性线的转换对UPS性能的影响和对策

由于低压配电系统接地故障保护(GFP)的需要,市电与备用发电机组电源转换电路,必须采用4极自动转换开关(ATS),而有些4极ATS在转换过程中存在中性线中断现象,严重影响了UPS的正常运行,由此引发的UPS故障和负载停电事件越来越受到关注。本文分析电信和数据中心常用市电和备用发电机组电源转换电路的性能,及其对GFP和UPS运行的影响,提出工程实用解决方案。     

基于目标全息反馈的STATCOM与发电机励磁协调控制研究

针对含有静止同步无功补偿器的发电机励磁系统,采用目标全息反馈法（Nonlinear Control designmethod with Objective Holographic Feedbacks,NCOHF）推导该系统的协调控制规律,使各控制目标均在给定性能指标中得以约束,以获得良好的系统性能.分别选定机端电压偏差、STATCOM的有功电流偏差以及无功电流偏差为控制目标,设计NCOHF协调控制器,并采用极点配置法整定控制器中的k参数.仿真结果表明：在该控制器作用下,发电机具有良好的输出特性,既能有效消除机端电压偏差,又能精准追踪电磁功率给定值;同时合理分配STATCOM的无功功率,提高电力系统的稳定性.因此,该协调控制器能很好地兼顾各控制目标的动、静态性能,并具有良好的应用价值.     

A power factor correction with two‐input current mode using voltage doubler rectifier

For rectifier circuits with a small capacity, such as those for consumer electronics and appliances, capacitor input‐type rectifier circuits are generally used. Consequently, various harmonics generated within the power system become a serious problem. Various studies of this effect have been reported. However, most of these employ switching devices, such as FETs and the like. The absence of switching devices makes systems more tolerant to overload, and brings low radio noise benefits. We propose a power factor correction scheme using a voltage doubler rectifier without switching devices. In this method, the input current is divided into two periods, where one period charges the small input capacitor and the other charges the large output capacitor. By dividing the input current into two different modes, the current conduction period can be widened and harmonics can largely be canceled between the two modes. Hence, the harmonic characteristics can be significantly improved, whereby the lower‐order harmonics, such as the fifth and seventh orders, are much reduced. The results are confirmed by theoretical and experimental implementations. © 2001 Scripta Technica, Electr Eng Jpn, 137(3): 52–58, 2001