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GB/T 7409 "Excitation Systems for Synchronous Machines" comprises three parts: ——Part 1: GB/T 7409.1 "Excitation Systems for Synchronous Machines-Definitions"; ——Part 2: GB/T 7409.2 "Excitation Systems for Synchronous Machines-Models for Power System Studies"; ——Part 3: GB/T 7409.3 "Excitation Systems for Synchronous Machines-Technical Requirements of Excitation System for Large and Medium Synchronous Generators" This part is the second part of GB/T "Excitation Systems for Synchronous Machines", which was firstly developed in 1987 and firstly revised in 1997, and this edition is the section revision. GB/T 7409.2-1997 is identical to IEC 60034-16-2: 1991 "Rotating Electrical Machines--Part 16: Excitation Systems for Synchronous Machines--Chapter 2: Models for Power System Studies". This part was revised by amending IEC 60034-16-2: 1991. This part has made reference to the domestic existing realistic model of generator excited system, the domestic current generator excited system computational model used in the stability analysis of power system and the standard IEEE Std.421.5, proposes the general and practical generator excited system computational model that can meet the requirements of the stability analysis of power system. There have been some significant changes in this part over GB/T 7409.2-1997 as follows: ——The model of excitation system is described specifically, the established model for generator excited system is able to meet the requirement for the main domestic generator excited system to have power system stability analysis; ——The regulation link and the model for power system stabilizer are supplemented; ——The mode of the limiter and power system stabilizer to act on voltage regulator is described. Appendix E provides the summary list of a comparison between this part and the clauses of IEC 60034-16-2: 1991-02, Appendix F provides the summary list of the technical differences of this part and IEC 60034-16-2: 1991-02 and the relevant reasons for your guidance. Appendixes A, B, C and D in this part are normative and Appendixes and F are informative. This part was proposed by China Electrical Equipment Industry Association. This standard is under the jurisdiction of National Technical Committee 26 on Electric Rotating Machinery of Standardization Administration of China. Zhejiang Electric Power Test & Research Institute is in charge of the drafting of this parts, and China Electric Power Research Institute, Harbin electric machinery Co., Ltd.(HEC), North China Electric Power Research Institute Co. Ltd., Shanghai Turbine Generator Co., Ltd., Dongfang Electric Machinery Co., Ltd., Nanjing Automation Research Institute, Guangzhou Electric Apparatus Research Institute, Shandong Jinan Power Equipment Factory, Beijing BEIZHONG Steam Turbine Generator Co., Ltd., Hydropower and Water Resources Planning and Design General Institute and other organizations participate in drafting this part. Chief drafting staffs of this part: Zhu Shizhang, Liu Zenghuang, Li Guoliang, SuWeimin, Xu Fuan, Wu Tao, Liu Mingxing, Wang Dawei, Lv Hongshui, Xu Jingtao, Yin Guoji, Zhang Yuhua, Liu Guoyang, Pu Jun and Chen Xinqi. The previous editions of the standards replaced by this part are as: ——GB 7409—1987; ——GB/T 7409.2—1997. Introduction When the behaviour of synchronous machines is to be accurately simulated in power system stability studies, the excitation system of these machines shall be modeled adequately. Since expenditure of data acquisition, programming and computation has to be limited in so far as is permissible, it is necessary to use simplified models that provide reasonable accuracy. The models shall adequately represent the actual excitation system performance: ——During the steady-state conditions prior to occurrence of the fault studied; ——During the time interval from application to clearing of fault; ——During the oscillations following fault clearing. The excitation modeling does not account for the frequency deviations. It is assumed that in stability studies, the frequency deviations of up to ±5% from the rated frequency can be neglected as far as the excitation system is concerned. The excitation system models shall be valid for the steady-state conditions and for the natural oscillation frequency of the synchronous machine. The oscillation frequency range to be covered will typically be from 0Hz to 3Hz. The operation of protective functions and field discharge or overvoltage suppression equipment is beyond the scope of these models. The excitation system modeling methods and standard models may also be used for studies of other dynamical problems regarding synchronous machines, for example, studies of out-of-step operation, sub-synchronous resonance or shaft torsional effects. However, the models shall then be checked to determine their suitability for that purpose. The general functional block diagram in Figure 1 indicates the various excitation system components which have to be considered in the power system stability studies. These components include: ——Voltage control elements; ——Limiters; ——Power system stabilizer (if used); ——Exciter. The main distinctive feature of an exciting power unit is the manner in which the exciting power is supplied and converted. Figure 1 General Functional Block Diagram of Excitation Systems (within the dotted block) for Synchronous Machines Excitation Systems for Synchronous Machines – Models for Power System Studies 同步电机励磁系统 电力系统研究用模型 1 Scope The excitation system simulation block diagram and the corresponding mathematical models, as well as the terms and definitions of parameters and variables included thereinto specified in this part of GB/T 7409 apply to the power system stability studies. 2 Normative References The following standards contain provisions which, through reference in this part of GB/T 7409, constitute provisions o this part. For dated reference, subsequent amendments to (excluding correction to), or revisions of, any of these publications do not apply. However, the parties whose enter into agreement according to these specifications are encouraged to research whether the latest editions of these labels are applied or not. For undated references, the latest editions of the normative documents are applicable to this part. GB/T 7409.1-2008 ""Excitation Systems for Synchronous Machines-Definitions" [IEC 60034-16-1: 1991; MOD] 3 Exciter Categories: Graphical Representation and Mathematical Models for Stability Studies 3.1 DC Exciter Although not frequently used on new machines in recent years, DC exciters are considered because many synchronous machines presently in service are equipped with this type of exciter. Figure 2 shows a graphical representation of the type with one separately excited field winding and Figure 3 shows the corresponding model of this exciter. The term KE has been introduced in model to account for the characteristics of exciters having self-excitation. Note: KE=1 in case of separately-excited exciters. Figure 2 Exciter of DC Exciter with One Separately-excited Winding Figure 3 Model Corresponding to Figure 2 Excitation control adopts with mechanical, electromagnetic and electronic control devices. Considering the winding percentage and importance of units equipped with DC exciters, the simple model of Figure 3 shall prove adequate for these cases. 3.2 AC Exciter AC exciters employ an AC exciter with static or rotating rectifier to produce the field current for the synchronous machines. The rectifiers may be controlled or uncontrolled. In case of uncontrolled rectifiers, control is effected via one or one field windings of the AC exciter. It is essential to know the source of supply for the AC exciter field current in order to simulate this exciter. This power supply may be an auxiliary exciter or a potential or compound static power supply. Figure 4 shows the graphical representation of an AC exciter with an uncontrolled stationary rectifier. The stationary rectifier is fed from the AC exciter and delivers DC current to the field winding of the synchronous generator via electrical brushes and slip-rings. The connection of the rotating field winding of the exciter to the excitation control equipment is also made by slip-rings and electrical brushes. Figure 5 shows the graphical representation of an AC exciter (brushless exciter) with an uncontrolled rotating rectifier and permanent magnet auxiliary exciter for supply of the excitation control equipment. The rectifier rotates on a shaft common to the synchronous machine and the rotating armature of AC exciter. The output of rotating rectifier id connected without slip-rings or electrical brushes directly to the field winding of the synchronous machine. Figure 4 AC Exciter with Uncontrolled Stationary Rectifier Figure 5 Rotating Exciter with Uncontrolled Rotating Rectifier (Brushless Exciter) The AC exciter can be modeled as shown in Figure 6. This model is used to account for both the steady-state and transient exciter loading effects (In certain cases, an even detailed model may be used to take in account the effects of transient loads).Depending on the data completeness of exciter, a model for exciter not representing the phase inversion function may be made, where XE is zero. A simplified model for AC exciter is shown in Figure 7. Although it accounts only for the steady-state load effects by use of load saturation curve, it may be adequate for most studies. The use of the simplified model may also be indicated where complete data are not complete data are not available. Figure 6 Detailed Model of an AC Exciter Figure 7 Simplified Model of an AC Exciter 3.3 Potential Source Static Exciter Potential source static exciters use rectifier transformers which can be supplied from an auxiliary generator mounted on the same shaft as the synchronous machine, from an auxiliary bus bar not independent on the main generator voltage or from the synchronous machine terminal voltage. The latter is called a self-shunt static exciter and the voltage variations of this self-shunt static excitation system shall be taken into account for the performance and modeling. Figure 8 shows the potential source static exciter. The mathematical models of potential source static exciter may be represented as Figure 9 or Figure 10. Figure 8 Potential Source Static Exciter The controlled rectifying device adopts fully controlled bridge or may also adopts the semi-controlled bridge with a half thyristor and a half diode. The output voltage is limited frequently by controlling the triggering corner, which is expressed with UP + and UP- . The route of semi-controlled bridge can not be inversed, and the value of UP- is equal to zero. The most commonly-used controlled rectification bridge only allows the passage of field current in positive direction. When the disturbance at ends of synchronous machine causes negative field current, the mathematical model in Figure 9 thereby will be invalid, in this case, the voltage of the synchronous machine field winding will be no longer controlled by the regulator but depends on other factors, this is beyond this part. Figure 9 Model of Potential Source Exciter (I) Figure 10 Model of Potential Source Exciter (II) Only in particular cases where the equipment is required to allow the passage of positive and negative field current, the mathematical model shown in Figure 9 will be valid. 3.4 Compound Source Static Exciter Compound source static exciters use rectifier transformers supplied from both current and voltage sources (from synchronous machines). There are a number of designs possibilities, including: current source and voltage source are of parallel connection at the DC side, in series at the DC side, of parallel connection at the AC side and in series at the AC side, and others. The compound source static exciters are rarely used, and those in series at the AC side is illustrated only. Figure 11 illustrates the concept of addition of voltage from two sources in series on the DC side of the rectifier. The reactors with air space will convert the current source into voltage source, or the current source transformers with air space may be used to directly convert the current source into voltage source. The corresponding model of which is given in Figure 12. Figure 11 Compound Source Static Exciter with Addition of Voltages in Series on the AC Side Figure 12 Model Corresponding to Figure 11 3.5 Mathematical Models for the Control Function A considerable part of the effort required to prepare large scale system stability studies is in collecting and determining date for the mathematical model related to this system study. The use of simplified mathematical models to reduce this effort may be restricted sometimes. For example, the use of simplified model will bring many difficulties when studies extend beyond the first rotor angle swing as the determination of the power system stability of modern power grid generally requires the simulation to be continued for many seconds and many swing oscillations. Thus simplification will be ruled out in some instances. 3.5.1 Models for voltage measurement and load current compensation units Generally, modeling of generator terminal voltage sending is common to all voltage regulators. Figure 13 shows voltage sensing combined with load current compensation on the AC side. In this case the input variables (generator voltage and current) are entered in phasor form and the resulting signal is then rectified. Load current compensation is normally used in one of the following forms: Figure 13 Terminal Voltage Signal and Load Current Compensation ——When units are paralleled with no impedance between them, the current compensation is used to create an artificial coupling impedance so that the units will share reactive power reasonably. For this case, Xc shall have a positive value. ——When a single unit is connected through a significant impedance to the system, or when two or more units are connected through individual transformers, it may be desirable to regulate voltage at a point beyond the machine terminals. For example, it may be desirable to compensate for a portion of the transformer impedance. For these cases, Rc and Xc take on negative values. In most cases of load current compensation, the Rc component is negligible and only a value of Xc is required. In this case, it is sufficient to reduce the load current influence to the reactive component, the element with this reducing function is designated as reactive current compensator. When compensator is not employed, only the filter for the rectified terminal voltage remains in Figure 13. While the filtering link may be complex, for modeling purposes, it can usually be reduced to the single time constant. For many systems, this time constant is rather small and provision shall be made set it to zero The terminal voltage after adding load compensator influence and filtering is compared with a reference which represents the desired terminal voltage setting value. The equivalent voltage regulator reference signal, UREF, is chosen to satisfy the initial operating conditions. When compensator is sued, it has to be noted that it may add positive or negative damping in case of power oscillations. 3.5.2 Models for regulation link The regulation link of excitation control realizes the field adjustment and stable control functions. Generally, the regulation link includes the following several forms: serial PID regulation link, parallel PID regulation link, transient feedback regulation link and exciter time constant compensation link. Moreover, several types of regulation links may be combined. a) Serial PID regulation link Model for the serial PID regulation link is given in Figure 14. This regulation link is composed of two stages of lead-lag links when Kv is set to be 1.The regulation link has pure integrating element and realizes isochronous control when Kv is set to be zero. Figure 14 Serial PID Regulation Link b) Parallel PID regulation link Model for the parallel PID regulation link is given in Figure 15. Figure 15 Parallel PID Regulation Link c) Transient feedback regulation link Model for the transient feedback regulation link is given in Figure 16. The input signal of transient feedback link is the output Ur of regulator in the static excitation system and may be the current signal Uie of exciter field in the exciter excitation system, or the voltage Uf of generator field. The output signal of the transient feedback link is added to the addition point of voltage or the output of PID regulation link. Figure 16 Transient Feedback Regulation Link d) Exciter time constant compensation link The exciter time constant compensation link is used to reduce the equivalent time constant of exciter. The input signal of this link is the generator field voltage signal or exciter field current signal, and is fed back to the output of PID regulation link, as shown in Figure 17. Figure 17 Exciter Time Constant Compensation Link 3.5.3 Limitation Attentions shall be paid to separate the “wind-up” limitation and “non-wind-up” limitation. Representations of “wind-up” limitation and “non-wind-up” limitation are given in Appendix D. 3.5.4 Models for power system stabilizers Generally, the input signals of power system stabilizer include the generator active power, frequency of machine terminal voltage, generator speed or their combination. The power system stabilizer may be used to operating conditions of generator and motor, however, the parameters shall be calibrated respectively. Generally, the output signals of power system stabilizer are superposed to the voltage addition point of voltage regulator. The output quantity of power system stabilizer superposed to the voltage addition point has the same reference value as the generator voltage. The reference value of the output quantity of power system stabilizer superposed to other points is the reference value of that superposed to the voltage addition point multiplied by the dynamic gain from the voltage addition point to the delivery phase addition point of power system stabilizer under the oscillation frequency requiring key suppression. The input quantity of power system stabilizer has the same reference value as generator. a) Model for single input signal power system stabilizer——PSS1 Type PSSl type model for single input signal power system stabilizer comprises signal measuring link, two-stage separate straight link, shaft torsional oscillation filter, three-stage lead-lag link, gain adjustment link and output limitation link, as shown in Figure 18.The Input signal may be generator active power machine terminal voltage frequency or generator speed. Contents Foreword I Introduction III 1 Scope 2 Normative References 3 Exciter Categories: Graphical Representation and Mathematical Models for Stability Studies 3.1 DC Exciter 3.2 AC Exciter 3.3 Potential Source Static Exciter 3.4 Compound Source Static Exciter 3.5 Mathematical Models for the Control Function 3.6 Model of Excitation System 4 Nomenclature 4.1 Parameters 4.2 Variables Appendix A (Normative) Per Unit System Appendix B (Normative) Rectifier Regulation Characteristics Appendix C (Normative) Saturation Function Appendix D (Normative) Representation of Limits Appendix E (Informative) Comparison Between Clauses of This Part and IEC 60034-16-2: 1991-02 By Numbers Appendix F (Informative) Technical Differences of This Part over IEC 60034-16-2: 1991-02 and the Reasons 同步电机励磁系统 电力系统研究用模型 1 范围 GB／T 7409的本部分规定的励磁系统模拟简图及相应的数学模型，以及其中包括的参数和变量的术语定义适用于电力系统稳定性研究。 2规范性引用文件 下列文件中的条款通过GB／T 7409的本部分的引用而成为本部分的条款。凡是注日期的引用文件，其随后所有的修改单(不包括勘误的内容)或修订版均不适用于本部分，然而，鼓励根据本部分达成协议的各方研究是否可使用这些文件的最新版本。凡是不注日期的引用文件，其最新版本适用于本部分。 GB／T 7409．1—2008 同步电机励磁系统 定义[IEC 60034-16-1：1991，MOD) 3励磁功率单元分类——图示法及稳定性研究的数学模型 3．1 直流励磁机励磁功率单元 近年来，虽然新机组已很少采用直流励磁机，但还有许多运行中的同步电机装有这类励磁机。图2就是一种采用它励绕组的直流励磁机励磁功率单元简图，图3表示该励磁功率单元的模型。模型中用术语KE来描述有自励分量励磁机的特性。注意：采用它励励磁机时KE=1。 图2 采用一个它励绕组的直流励磁机 励磁功率单元 励磁控制采用机械式、电磁式和电子式控制装置。 图3与图2相对应的模型 考虑到采用直流励磁机的机组数量和重要程度的减小，对上述励磁控制形式，统一用图3的简图描述即可满足要求。 3．2 交流励磁机励磁功率单元 交流励磁机励磁功率单元利用交流励磁机带静止或旋转整流器，给同步电机提供磁场电流。整流器可以是可控的或者是不可控的。采用不可控整流器时，可通过一个或多个交流励磁机磁场绕组产生控制作用。 分清提供交流励磁机磁场电流的电源，是模拟该励磁功率单元的基础。该电源可为副励磁机，也可为电压或复合静止电源。 图4表示交流励磁机带不可控静止整流器的励磁功率单元简图。由交流励磁机供给静止整流器电源，整流器的输出经电刷和滑环给同步发电机的磁场绕组。励磁机的旋转磁场绕组到励磁控制设备也是通过滑环和电刷进行电联接的。 图5表示交流励磁机(无刷励磁机)带不可控旋转整流器和永磁式副励磁机的简图，励磁控制设备的电源由永磁式副励磁机提供。整流器和交流励磁机的电枢与同步电机同轴旋转，旋转整流器的输出不需用滑环或电刷，而直接与同步电机的磁场绕组联接。 图4 带不可控静止整流器的交流励磁机 励磁功率单元 图5带不可控旋转整流器的旋转励磁 功率单元(无刷励磁) 交流励磁机励磁功率单元的模型如图6所示。该模型用以描述励磁机带负载时的稳态和瞬态特性(在某些情况下考虑到瞬时负载影响，需用更详细的模型)。取决于励磁机数据完整程度，可以构成不表达换相作用励磁机励磁功率单元模型，即设XE为零。 图7表示交流励磁机励磁功率单元的简化模型。虽然用负载的饱和曲线只能描述其稳态负载特性，但可以满足许多研究的要求。还应指出，不可能获得全部数据时可用简化模型。 图6 交流励磁机励磁功率单元详细模型 图7 交流励磁机励磁功率单元简化模型图 3．3 电势源静止励磁功率单元 电势源静止励磁功率单元采用整流变压器，电源取自装在与同步电机同轴的辅助发电机、或取自与主发电机电压无关的辅助母线、或取自同步电机的输出端。后者称作自并励静止励磁功率单元，自并励静止励磁系统的性能和模型应考虑受电压变化的影响。电势源静止励磁功率单元如图8所示。电势源静止励磁功率单元数学模型可以表示为图9或者图10。 图8 电势源静止励磁功率单元 可控整流装置采用全控桥，也可采用一半晶闸管、一半二极管的半控桥。常常通过控制触发角限制输出电压，用UP+和UP-来表示。半控桥线路不能逆变，UP-的值等于零。 最常用的可控整流桥只允许正向励磁电流通过。若同步电机端部扰动引起负的磁场电流，图9的数学模型对此就不再是有效的了，在这种情况下，同步电机磁场绕组的电压不再受调节器的控制，而决定于其他因素，这不在本部分范围内论述。 图9 电势源励磁功率单元模型之一 图10 电势源励磁功率单元模型之二 只有在特殊情况下要求设备允许流过正向和负向励磁电流时，图9的数学模型才适用。 3．4 复合源静止励磁功率单元 复合源静止励磁功率单元采用电流源和电压源(取自同步电机)供电的两种整流变压器。设计的形式有电流源和电压源在直流侧并联、直流侧串联、交流侧并联和交流侧串联等多种形式。复合源静止励磁功率单元使用甚少，这里仅说明交流侧串联的复合源静止励磁功率单元。 图11给出了两个电源在整流器交流侧串联、电压相加的原理图。带有气隙的电抗器将电流源转换为电压源，也有采用带气隙的电流源变压器直接将电流源转换为电压源。图12给出相应的模型。 图11 交流侧串联、电压相加的复合源静止励磁功率单元 图12图11的模型 3．5 控制功能的数学模型 系统稳定性研究的大部分工作在于收集整理并确定与该系统研究有关的数学模型数据。对系统进行适当地简化会减少许多繁琐工作，但有时这种简化也会受到限制。例如，当要计算超过转子角第一次摆动以外的特性时，使用简化的模型会带来许多困难，因为现代电网的电力系统稳定性通常要经过数秒或数次振荡后方能确定。因此，在某种情况下，模型是不能简化的。 3．5．1 电压测量和负载电流补偿单元模型 通常，模拟发电机端电压信号是所有电压调节器共用的。图13表示交流侧电压信号与负载电流补偿的合成。在此情况下，将输入变量(发电机电压和电流)进行相量相加，然后将合成信号整流。通常，负载电流的补偿采用下面的某一种形式: 图13端电压信号及负载电流补偿 ——当机组间未经阻抗直接并联时，采用电流补偿，造成一个人为的阻抗匹配，以使机组能合理地分担无功功率。这种情况下，Xc应为正值。 ——当单一机组通过大的阻抗联到系统，或两台及多台机组通过各自变压器联到系统时可能要求调节发电机端外某点的电压。比如，可以补偿变压器的部分阻抗，在这些情况下，Rc和Xc取负值。 多数负载电流的补偿忽略Rc分量，而只要求Xc值，在此条件下，负载电流的影响可视为无功分量的影响，起该作用的部件称作无功电流补偿器。 不使用补偿器，而仅仅用于端电压整流后的滤波时，仍适用于图13。另一方面，滤波环节可能是复杂的，为了模拟，可以简化为一阶惯性环节，在许多情况下此时间常数很小，可忽略不计。 加入负载补偿器影响滤波后的端电压信号与参考信号比较，参考信号表示端电压的理想整定值，选择等效电压调节器的参考信号UREF，以满足初始运行条件。 当使用补偿器时，应注意可能会在功率振荡的情况下附加上正的或负的阻尼。 3．5．2 校正环节模型 励磁控制的校正环节实现励磁调节和稳定控制功能。校正环节一般有以下几种类型：串联型PID校正环节、并联型PID校正环节、软反馈校正环节和励磁机时间常数补偿环节。也有几种校正环节组合的情况。 a) 串联型PID校正环节 串联型PID校正环节模型见图14。Kv设置为1时校正环节由两级超前滞后环节组成。Kv设置为零时校正环节带纯积分环节，实现无差调节。 图14 串联型PID校正环节 b) 并联型PID校正环节 并联型PID校正环节模型见图15。 图15并联型PID校正环节 c) 软反馈校正环节 软反馈校正环节模型见图16。软反馈环节输入信号在静止励磁系统中为调节器输出Ur，在励磁机励磁系统中可以是励磁机磁场电流信号Uie或者发电机磁场电压Uf。软反馈环节输出信号加到电压相加点或者PID校正环节的输出。 图16 软反馈校正环节 d) 励磁机时间常数补偿环节 励磁机时间常数补偿环节用以减少励磁机等效时间常数。励磁机时间常数补偿环节的输入信号为发电机磁场电压或励磁机磁场电流信号，反馈到PID校正环节的输出，见图17。 图17励磁机时间常数补偿环节 3．5．3 限幅环节 要注意区分内限幅和外限幅两种限幅环节。内限幅和外限幅的表达见附录D。 3．5．4 电力系统稳定器模型 电力系统稳定器输入信号一般有发电机有功功率、机端电压的频率、发电机转速或它们的组合。电力系统稳定器可以用于发电机和电动机工况，但是参数需要分别整定。 电力系统稳定器输出信号一般叠加到电压调节器电压相加点上。叠加到电压相加点的电力系统稳定器输出量的基准值同发电机电压的基准值。叠加到其他点的电力系统稳定器输出量的基准值为叠加到电压相加点的电力系统稳定器输出量的基准值乘以需重点抑制的振荡频率下电压相加点到电力系统稳定器输出相加点的动态增益。电力系统稳定器输入量的基准值同发电机基准值。 a) 单输入信号电力系统稳定器模型——PSS1型 PSSl型单输入信号电力系统稳定器模型由信号测量环节、两级隔直环节、轴系扭振滤波器、三级超前滞后环节、增益调整环节和输出限幅环节组成，见图18。输入信号可以是发电机有功功率、机端电压的频率或发电机转速。 图18单输入信号电力系统稳定器模型——PSSl型 b) 合成加速功率型电力系统稳定器模型——PSS2型 PSS2型合成加速功率型电力系统稳定器模型见图19。PSS2型模型采用发电机转速(或频率)和有功功率作为输入信号US11和US12，经过运算产生机械功率变化量信号，该信号减去有功功率变化量信号即为加速功率变化量信号，以此作为电力系统稳定器校正信号输入到超前滞后环节、增益调整环节和限幅环节。 |
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| GB/T 7409.2-2008, GB 7409.2-2008, GBT 7409.2-2008, GB/T7409.2-2008, GB/T 7409.2, GB/T7409.2, GB7409.2-2008, GB 7409.2, GB7409.2, GBT7409.2-2008, GBT 7409.2, GBT7409.2 |