晶闸管控制的串联电容补偿模型的综合研究

采用拉氏变换精确推导出适用于瞬时过渡阶段和稳态阶段的TCSC回路 中电容器、电抗器和晶闸管元件的电压和电 流数学表达式,再采用傅里叶分析进一步导出了TCSC基波阻抗和晶闸管触发角之间精确的数 学关系。利用电磁暂态程序(EMTP)验证了TCSC回路数学分析的正确性。此外,建立了带有微 机控制的完整的TCSC动模试验装置,并通过动模试验进一步同TCSC回路的数学分析和仿真结 果作比较。动模试验的结果与理论分析和仿真的结论较好地吻合,且证实了数学分析和数字 仿真中采用线路电流保持正弦假设的合理性。     

可控串联补偿电容器控制角模型及其在静态电压稳定研究中的应用

提出一个可控串联补偿电容器(TCSC)静态模型，将TCSC基频等值电抗表达为其控制角的显函数并考虑了其自身的功率损耗。将控制角作为状态变量处理，推导了4种典型控制模式下的TCSC牛顿潮流方程并在连续潮流算法中予以实现，并指出恒功率控制、恒电流控制和恒相角差控制中所需的控制参考量由系统基本工况下指定线路补偿度的恒阻抗控制获得。用IEEE30母线系统进行仿真计算，结果表明该模型具有较高的求解效率及数值稳定性，通过控制角可以方便地获取线路的补偿度。用该模型进行电压稳定分析表明，选择最优的安装位置及合适的控制模式是提高电压稳定性的关键因素。恒阻抗控制对提高电压稳定性的效果是最好的，而不适当的控制模式以及不适当的安装位置则可能导致系统的电压稳定裕度降低。     

Calculation of damping torque of power systems compensated with TCSC

The thyristor‐controlled series capacitor (TCSC) is being developed to improve the transmission capability of power systems. The TCSC is thought to compensate transmission line reactance without causing subsynchronous resonance (SSR). However, in order to evaluate its effect quantitatively, we must calculate the frequency response of the generator damping torque. Simulations need a long computing time, and it is hard to choose the frequency freely. In this paper, we propose a method of analytically calculating the damping torque. First, when a generator rotor oscillates at some frequency, two voltage components appear. We analytically calculate the damping torque from small current variations due to the voltage components. The damping characteristic changes depending on the method of firing thyristors. The best characteristic is obtained when triggering with reference to the fundamental wave of TCSC voltage or current is used. By choosing an appropriate firing angle, we can drastically reduce negative damping by the TCSC. The damping characteristic is closely related to the system impedance. The fact that the TCSC has large resistance in the 0 to 60 Hz range helps significantly in improving the characteristic. Lastly, numerical simulations of SSR are used to examine the validity of our investigation. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 143(1): 39–49, 2003; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10068     

电抗器品质因数对TCSC特性的影响及阻抗特性的双解现象

可控串联电容器(Tcsc)装置的晶闸管控制支路电抗器(TCR)品质因数只能是有限值，该文通过时域数字仿真分析了这一参数对TCSC稳态阻抗特性的影响。仿真分析结果表明在电抗器品质因数有限的情况下，TCSC等效阻抗特性的谐振点相对理想情况会出现偏移；同时，在容性运行区间，对于同样的触发角指令，Q值越小，TCSC的等效基频电抗也越小，而在感性运行区间，情况则刚好相反。这种影响在感性和容性运行区间还因TCSC同步触发控制方式不同而存在较大的差异。当以电容电压过零点为同步触发参考时标时，触发角指令与等效阻抗之间是单值对应关系，而以线路电流为同步触发参考时标时，触发角指令与等效阻抗之间是双值对应关系，即所谓的双解阻抗特性。文章进一步研究了线电流同步方式下TCSC等效基频阻抗呈现双解的现象，指出产生该现象的根本原因是采用了不同的触发参考时标。TCSC等效基频阻抗特性的双解现象实际上是在以线路电流过零点为触发参考时标时TCSC表现出的一种特殊运行特性。它与以电容电压同步触发参考时标的阻抗特性之间具有确定的对应关系。在两种不同的触发时标下，通过详细时域仿真验证了上述结论。     

可控串联补偿(TCSC)系统感性微调区的Pitchfork分叉现象

叙述了可控串联补偿（ＴＣＳＣ）装置在感性微调区工作的动态模拟实验结果,用Ｐｏｉｎｃａｒｅ映射时分析了ＴＣＳＣ系统的动态稳定性。理论分析、ＥＭＴＰ数值仿真及动模实验均证明,超过一个临界触发角后,ＴＣＳＣ系统发生Ｐｉｔｃｈｆｏｒｋ分叉现象。     

可控串补基波阻抗数值算法及仿真研究

可控串联补偿技术不仅可以提高输电线路的输送容量、改善电网的潮流分布、增强系统的暂态稳定性,而且还可以抑制低频功率振荡和次同步谐振等.该研究对TCSC的基本结构及运行原理进行了介绍,通过求取TCSC回路中各电压电流,建立TCSC的数学模型,并进行谐振点分析,利用Matlab软件进行数值仿真计算,最后得到TCSC的基波阻抗...     

考虑阻抗双解现象的可控串补模式切换控制方法

可控串联补偿(thyristor controlled series capacitor,TCSC)的模式切换对电力系统的稳定控制具有重要意义。TCSC阻抗双解现象的存在对其模式切换提出了更高的要求,单一改变触发角的方法无法实现模式切换。在考虑阻抗双解现象影响的基础上,提出了一套相应的TCSC模式切换控制方法。通过强制晶闸管支路电流与线路电流同步,实现由容性区到Bypass模式的切换;在由容性区到感性微调模式切换的过程中提出了晶闸管条件触发的方法,即当线路电流和电容电压满足同向条件时晶闸管才触发导通。同时为及时向切换控制提供线路电流同步信号,提出了一种预测电流过零的新方法。数字仿真及动模实验结果表明,提出的切换方法能使切换过程平稳迅速,且动态特性良好。     

可控串联电容补偿器的负阻尼特性研究

由于在暂稳控制器的设计中通常将可控串联电容补偿器(TCSC)处理为带限幅器的一阶惯性环节,而忽略了电力系统动态行为对TCSC脉冲触发过程影响以及装置动态响应特性的研究.文中建立了装有TCSC的电力系统的扩展Phillips Heffron模型,通过分析TCSC对系统同步和阻尼转矩的贡献,给出了在开环定触发角控制下TCSC表现为负阻尼特性的解析解.基于NETOMAC的数字仿真结果验证了模型分析的正确性,同时指出通过合适的底层控制策略可以减弱和消除负阻尼,有效地改善 TCSC的动态响应特性.     

A Comparative Study of Symmetrical Three-Phase Circuits for Phase-Controlled AC Motor Drives

The speed of an induction motor in certain types of drives can be adjusted by phase control of the applied voltage. Three pairs of inverse-parallel thyristors are required for three-phase bipolar symmetry, but several different arrangements of the thyristors and motor windings are possible. A direct series connection of thyristors and windings in each phase can be made; the three phases can then be connected in delta, wye, or wye with neutral return. Alternatively, a delta connection of thyristor modules can be inserted in the opened neutral junction of wye-connected windings. Representation of the motor as a counter EMF in series with leakage reactance allows a simplified analysis of the current waveforms in terms of the thyristor conduction angle. With a given fundamental current, the current harmonics in the motor windings and in the supply lines for each of the circuits can then be compared. The results are equally applicable to thyristor-controlled inductive loads such as may be used for reactive power adjustment.     

TCSC阻抗双解现象的机理研究

TCSC是靠调整触发角来获得需要的命令阻抗，因此命令阻抗与触发角的关系尤为重要，以往对TCSC阻抗双解研究局限于讨论电抗器品质因数的影响，该文讨论了考虑晶闸管导通特性和电抗器支路品质因数影响时TCSC的阻抗特性，文中通过相量图分析发现，即使在品质因数不变的情况下，随着晶闸管导通电流的增大，电容电压过零点与线路电流过零点之间的相位差也会逐渐减小，引起晶闸管实际导通幅度和宽度的减小；指出了造成TCSC双解现象的根本原因是晶闸管的导通受阻，其受阻程度由电抗器支路的电流和等效品质因数2个因素决定：线路电流同步方式下晶闸管导通电流的幅度和宽度均受阻；而电容电压同步下，晶闸管导通电流只有幅度受阻，因此阻抗双解现象在线路电流同步方式下更容易出现。数字仿真和动模实验结果分别验证了阻抗双解现象的存在。     

考虑电抗器支路电阻影响时的TCSC稳定运行区域内的双解现象

基波阻抗和触发角的关系是可控串补(TCSC)底层触发控制的关键所在。该文建立了恒流源下的考虑晶闸管导通压降和电抗器上所带电阻影响的TCSC的数学模型，进行了严密的数学推导，得出以线路电流同步时的触发角和导通角的隐式关系式，并应用数值方法求解该表达式，最终得出基波阻抗和触发角的关系曲线；发现了在TCSC的大部分稳定运行区域内，对应于同一触发角存在2个理论上的稳态解。当晶闸管导通压降和电抗器上所带电阻较大时，这2个稳态解都可以出现在工程中，尤其是出现在开发阶段的小容量模拟实验和动模实验中，从而为实际工程的开发和底层控制策略的设计提供了有力的理论依据。最后运用仿真手段和动模实测数据验证了文中提出的理论。     

TCSC阻抗双解现象的机理研究

TCSC是靠调整触发角来获得需要的命令阻抗，因此命令阻抗与触发角的关系尤为重要，以往对TCSC阻抗双解研究局限于讨论电抗器品质因数的影响，该文讨论了考虑晶闸管导通特性和电抗器支路品质因数影响时TCSC的阻抗特性，文中通过相量图分析发现，即使在品质因数不变的情况下，随着晶闸管导通电流的增大，电容电压过零点与线路电流过零点之间的相位差也会逐渐减小，引起晶闸管实际导通幅度和宽度的减小；指出了造成TCSC双解现象的根本原因是晶闸管的导通受阻，其受阻程度由电抗器支路的电流和等效品质因数2个因素决定：线路电流同步方式下晶闸管导通电流的幅度和宽度均受阻；而电容电压同步下，晶闸管导通电流只有幅度受阻，因此阻抗双解现象在线路电流同步方式下更容易出现。数字仿真和动模实验结果分别验证了阻抗双解现象的存在。     

变耦电抗式可控串补基本特性研究

为搞清楚变耦电抗式可控串补的应用价值,必须对其技术经济性能进行研究。通过理论分析,得出了变耦电抗装置的特性、机理及选用方法,提出变耦电抗式可控串补装置的具体结线并指出其功率调节特性,提出晶闸管开关装置最佳换级控制方法;通过试验证明理论分析的正确性;经功率调节计算,变耦电抗式可控串补较之于TCSC所需主设备容量大幅度减少。初步研究结果表明,变耦电抗式可控串补具有良好的功率调节特性和换级暂态特性,若只用于功率调节,要比TCSC显著降低工程造价。     

TCSC暂态过程中晶闸管导通角特性的研究

当晶闸管触发角发生阶跃时,由于TCSC电路固有的电磁暂态特性,使得电容电压过零点发生偏移,因此导通角不会立刻达到预定目标值。章首先给出并证明了触发角阶跃变化与初始导通角之间的定性关系;然后通过分析晶闸管导通期间电容电压的解耦特性,推导出导通角的估算公式,定量地描述了暂态过程中导通角的变化规律。数字仿真验证了上述分析结论并进一步发现：导通角变化趋势与TCSC基频阻抗特性是完全一致的,从而揭示了选择不同同步信号时TCSC会表现出不同暂态响应特性的内在原因。     

An Investigation into Thyristor-based Seven-level Multi-level Current Reinjection Current Source Converter

This article presents a comprehensive analysis of the thyristor based seven-level multi-level current reinjection current source converter. The seven-level multi-level current reinjection current source converter increases the pulse number from 12 to 72, thereby producing high-quality AC current and DC voltage waveforms, thus lowering harmonics on both sides. The ability to switch thyristors with a negative firing angle using auxiliary bridge reinjection insulated-gate bipolar transistors enables the converter to have a leading power factor. This article also details the design of the firing angle controller for the seven-level multi-level current reinjection current source converter, which enables the converter to have a negative firing angle. A wide range of PSCAD/EMTDC simulation results are presented to evaluate the performance of this converter, especially the effect of RC snubbers across the reinjection insulated-gate bipolar transistors.     

Calculation of frequency response of thyristor‐controlled series capacitor

In this paper, we propose a method of analytically calculating an impedance of a thyristor‐controlled series capacitor (TCSC). The TCSC consists of a thyristor‐controlled reactor (TCR) and a capacitor. If a small voltage component of frequency f superimposes the TCSC voltage of frequency f_o, then current components of frequency (nf_o ± f) flow through the TCR, where n takes even numbers. We derive theoretical equations for them. In the derivation, we consider an influence of odd harmonics in the TCSC voltage. We also consider deviations in its zero‐crossing times due to the superimposed voltage. The current components flow through the capacitor and the transmission line, and produce new voltage components of frequency (nf_o ± f). In order to count their influence, we introduce admittance matrices for the TCR, the capacitor, and the transmission line. By solving a network equation consisting of the matrices, we can obtain the distribution of the voltage and current components. We define the impedance of TCSC as a ratio of the voltage component of frequency f to the current one of the same frequency. The impedance analytically obtained corresponds well with that obtained by simulations. Its frequency responses vary with the firing method of thyristors. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 139(3): 35–44, 2002; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.1158     

±1100kV/5000A特高压直流输电换流阀非周期触发试验仿真研究与试验验证

换流阀是直流输电工程中的核心设备,除电气设计及结构设计均比较复杂外,电器元件的选择也是核心工作,随着大功率电力电子器件的飞速发展,其技术的先进性和运行的可靠性也得到了大幅度提升,6英寸晶闸管现已在特高压直流输电换流阀上得到了普遍使用。换流阀在挂网运行之前需要对其进行绝缘型式试验,绝缘型式试验是对换流阀的绝缘性能进行全面的考核,文中将对±1 100 kV直流输电换流阀绝缘型式试验中的非周期触发试验进行研究,非周期触发试验是对换流阀考核最为严格和全面的一项试验,旨在考核换流阀在操作冲击电压下通过冲击电流的能力,同时也考核了VCM对换流阀晶闸管器件开通和关断的控制及保护能力。笔者利用PSCAD仿真软件对±1 100 kV换流阀的非周期触发试验进行了仿真分析,分析结果可知,给单阀施加规定的操作冲击电压574.4 kV时,单阀通过冲击电流的能力约为6 045 A,并得到试验验证。     

中压配电网串联TCSC调压的应用研究

利用TCSC可以平滑地调节阻抗,实现对不同线路参数或不同负荷的线路进行电压调节,稳定负荷侧电压。对线路电压调节时考虑线路横向压降的影响,从而得到串联补偿容抗计算公式;由于晶闸管的导通压降会影响TCSC的等效基波容抗,因而采用串接受控电压源来消除影响;最后通过TCSC对辐射线路电压调节的仿真分析,说明仿真时通过串接受控电压源可以消除晶闸管导通压降对调压的影响,而在实际应用中只需对查表进行修正,则同样可实现对电压进行精确调节。     

Subsynchronous resonance analysis using a discrete time model of thyristor controlled series compensator

The characteristic of a thyristor controlled series compensator (TCSC) is nonlinear in nature. Usually the TCSC control systems employs a conventional type controller to obtain the reactance order, which in turn, is converted into the corresponding firing angle of the TCR through a look-up table. The main drawback of this approach is the absence of a closed-loop model through which the stability of the system can be analyzed. To alleviate this problem a linear, discrete-time state space model of a TCSC compensated transmission line in the d–q domain is proposed (Srivastava et al., Model-based control design of a TCSC compensated power system, to appear in Electrical Power and Energy Systems). This model is further utilized in this paper for damping torsional oscillations arising due to subsynchronous resonance (SSR). The model is interfaced with synchronous generator and turbine-shaft models to obtain a closed form homogeneous state space representation that is suitable for eigenvalue analysis. Through eigenvalue analysis it is shown that proper choice of control gains can effectively damp out SSR. The eigenvalue analysis results are subsequently validated through PSCAD/EMTDC simulation studies.     

可控串联补偿装置器件级数字仿真研究

在可控串联电容补偿装置（ＴＣＳＣ）的研究中,用电容、电感、晶闸管、ＭＯＶ等元件构造ＴＣＳＣ器件模型。选择合适的步长、触发才暂态稳定控制器,在实际多机系统中进行ＴＣＳＣ数字仿真研究。结果表明,所采用的ＴＣＳＣ器件模型和控制方法可在仿真中正确实现了ＴＣＳＣ的触发功能和控制功能。