CN111082436B - Direct-drive wind power plant oscillation suppression method and system based on phase-locked consistency - Google Patents

Direct-drive wind power plant oscillation suppression method and system based on phase-locked consistency Download PDF

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CN111082436B
CN111082436B CN201911382000.1A CN201911382000A CN111082436B CN 111082436 B CN111082436 B CN 111082436B CN 201911382000 A CN201911382000 A CN 201911382000A CN 111082436 B CN111082436 B CN 111082436B
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马静
吴升进
顾元沛
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North China Electric Power University
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    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
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Abstract

The invention relates to a direct-drive wind power plant oscillation suppression method and system based on phase locking consistency, belongs to the technical field of wind power generation systems, and solves the problem that in the prior art, because energy interaction exists among fans, subsynchronous/supersynchronous frequency oscillation divergence is increased. The method is applied to a wind power plant multi-machine system and comprises the following steps: collecting the current and/or voltage of a direct-drive wind power plant of the wind power plant multi-machine system in real time, and judging whether the direct-drive wind power plant generates subsynchronous/supersynchronous oscillation or not; if the judgment result is that the direct-drive fan phase-locked loop occurs, adjusting the voltage of the input end of the direct-drive fan phase-locked loop in the wind power plant multi-machine system to be the voltage of a grid-connected point; and the direct-drive fan phase-locked loop is connected to the outlet of the direct-drive fan. Correct and effective suppression of sub/super synchronous frequency oscillations of the direct-drive wind farm is achieved.

Description

一种基于锁相一致的直驱风电场振荡抑制方法及系统A direct-drive wind farm oscillation suppression method and system based on phase-locked consistency

技术领域Technical Field

本发明涉及风力发电系统技术领域,尤其涉及一种基于锁相一致的直驱风电场振荡抑制方法及系统。The present invention relates to the technical field of wind power generation systems, and in particular to a method and system for suppressing oscillations in a direct-drive wind farm based on phase-locked consistency.

背景技术Background Art

随着风电等新能源的大规模并网,电网的结构和运行特性发生了显著变化,尤其是风电引发的次/超同步频率振荡日益严重。2015年7月,我国新疆哈密地区大规模直驱风电场接入弱交流系统发生了次/超同步频率振荡,导致临近火电发电机组扭振保护动作停机,严重危害电网的安全运行和风电场的稳定控制。因此,如何分析风电场的次/超同步频率振荡机理,以及如何抑制次/超同步频率振荡的产生,已经成为实际工程中亟待解决的重要问题。With the large-scale grid connection of new energy sources such as wind power, the structure and operation characteristics of the power grid have changed significantly, especially the sub/supersynchronous frequency oscillation caused by wind power has become increasingly serious. In July 2015, a large-scale direct-drive wind farm in Hami, Xinjiang, my country, connected to a weak AC system and experienced sub/supersynchronous frequency oscillation, which caused the torsional vibration protection of the nearby thermal power generators to shut down, seriously endangering the safe operation of the power grid and the stable control of the wind farm. Therefore, how to analyze the sub/supersynchronous frequency oscillation mechanism of the wind farm and how to suppress the generation of sub/supersynchronous frequency oscillation have become important issues that need to be solved in actual engineering.

目前,国内外针对直驱风电场次/超同步频率振荡已展开相关研究,但多数研究的控制参数并不全面,且仅适用于单机风机系统或多机聚合风机系统,风电场多机对次/超同步频率振荡的影响及多机间的振荡交互等问题仍缺乏相应的研究论证。At present, relevant research has been carried out at home and abroad on the sub/supersynchronous frequency oscillations of direct-drive wind farms, but the control parameters of most studies are not comprehensive and are only applicable to single-machine wind turbine systems or multi-machine aggregated wind turbine systems. There is still a lack of corresponding research and demonstration on the impact of multiple machines in wind farms on sub/supersynchronous frequency oscillations and the oscillation interaction between multiple machines.

发明内容Summary of the invention

鉴于上述的分析,本发明旨在提供一种基于锁相一致的直驱风电场振荡抑制方法及系统,用以解决现有技术中由于风机间存在能量交互助增了次/超同步频率振荡发散的问题。In view of the above analysis, the present invention aims to provide a direct-drive wind farm oscillation suppression method and system based on phase-locked consistency, so as to solve the problem of sub/super-synchronous frequency oscillation divergence caused by energy interaction between wind turbines in the prior art.

本发明的目的主要是通过以下技术方案实现的:The purpose of the present invention is mainly achieved through the following technical solutions:

一方面,公开了一种基于锁相一致的直驱风电场振荡抑制方法,应用于风电场多机系统,所述方法包括如下步骤:On the one hand, a method for suppressing oscillations in a direct-drive wind farm based on phase-locked consistency is disclosed, which is applied to a multi-machine system in a wind farm. The method comprises the following steps:

实时采集所述风电场多机系统的直驱风电场的电流和/或电压,判断直驱风电场是否发生次/超同步振荡;collecting the current and/or voltage of the direct-drive wind farm of the wind farm multi-machine system in real time, and determining whether sub-synchronous/super-synchronous oscillation occurs in the direct-drive wind farm;

若判断结果为发生,则调整风电场多机系统中各直驱风机锁相环输入端的电压为并网点的电压;If the result of the judgment is that it has occurred, the voltage at the input end of the phase-locked loop of each direct-drive wind turbine in the wind farm multi-machine system is adjusted to the voltage of the grid connection point;

其中,所述直驱风机锁相环连接在直驱风机出口处。Wherein, the direct-drive fan phase-locked loop is connected at the outlet of the direct-drive fan.

在上述方案的基础上,还做出了如下改进:Based on the above solution, the following improvements are made:

进一步,所述方法还包括:Furthermore, the method further comprises:

若判断结果为发生,实时检测次/超同步振荡是否结束,若结束,则所述各直驱风机锁相环输入端的电压恢复为与所述锁相环相连的直驱风机的输出端电压。If the judgment result is that it occurs, it is detected in real time whether the sub/super synchronous oscillation is ended. If it is ended, the voltage at the input end of the phase-locked loop of each direct-drive fan is restored to the output end voltage of the direct-drive fan connected to the phase-locked loop.

进一步,所述实时采集直驱风电场的电流和/或电压为:Furthermore, the real-time acquisition of the current and/or voltage of the direct-drive wind farm is:

采集直驱风电场中风机并网点处的电流和/或电压;Collect current and/or voltage at the grid connection point of wind turbines in direct-drive wind farms;

或者,or,

直驱风电场中各直驱风机出口处的电流和/或电压。The current and/or voltage at the outlet of each direct-drive wind turbine in a direct-drive wind farm.

进一步,所述判断直驱风电场是否发生次/超同步振荡,包括:Further, the determining whether sub-synchronous/super-synchronous oscillation occurs in the direct-drive wind farm includes:

若所述采集到的并网点处或任一直驱风机出口处的电流和/或电压的频率处于次/超同步振荡频率范围内,则判定直驱风电场发生次/超同步振荡。If the frequencies of the current and/or voltage collected at the grid connection point or at any outlet of the direct-driven wind turbine are within the sub/super synchronous oscillation frequency range, it is determined that sub/super synchronous oscillation occurs in the direct-driven wind farm.

进一步,所述次同步振荡频率范围为2.5-50Hz;所述超同步振荡频率范围为50-97.5Hz。Furthermore, the subsynchronous oscillation frequency range is 2.5-50 Hz; the supersynchronous oscillation frequency range is 50-97.5 Hz.

另一方面,公开了一种基于锁相一致的直驱风电场振荡抑制系统,应用于风电场多机系统,所述系统包括:On the other hand, a direct-drive wind farm oscillation suppression system based on phase-locked consistency is disclosed, which is applied to a wind farm multi-machine system, and the system includes:

数据采集模块,用于实时采集所述风电场多机系统的直驱风电场的电流和/或电压;A data acquisition module, used for real-time acquisition of current and/or voltage of a direct-drive wind farm of the wind farm multi-machine system;

振荡判断模块,用于接收所述数据采集模块采集到的数据,并判断直驱风电场是否发生次/超同步振荡;An oscillation judgment module, used for receiving the data collected by the data collection module and judging whether sub-synchronous/super-synchronous oscillation occurs in the direct-driven wind farm;

振荡抑制模块,用于当所述振荡判断模块的判断结果为发生时,调整风电场多机系统中各直驱风机锁相环输入端的电压为并网点的电压;An oscillation suppression module, used for adjusting the voltage at the phase-locked loop input terminal of each direct-drive wind turbine in the wind farm multi-machine system to the voltage of the grid connection point when the judgment result of the oscillation judgment module is that the oscillation occurs;

其中,所述直驱风机锁相环连接在直驱风机出口处。Wherein, the direct-drive fan phase-locked loop is connected at the outlet of the direct-drive fan.

进一步,所述系统还包括:Furthermore, the system further comprises:

振荡恢复模块,用于当所述振荡判断模块的判断结果为发生时,控制所述数据采集模块和所述振荡判断模块实时检测次/超同步振荡是否结束,若结束,则所述各直驱风机锁相环输入端的电压恢复为与所述锁相环相连的直驱风机的输出端电压。The oscillation recovery module is used to control the data acquisition module and the oscillation judgment module to detect in real time whether the sub-synchronous/super-synchronous oscillation has ended when the judgment result of the oscillation judgment module is that the oscillation has occurred. If it has ended, the voltage at the input end of the phase-locked loop of each direct-drive fan is restored to the output end voltage of the direct-drive fan connected to the phase-locked loop.

进一步,所述实时采集直驱风电场的电流和/或电压为:Furthermore, the real-time acquisition of the current and/or voltage of the direct-drive wind farm is:

采集直驱风电场中风机并网点处的电流和/或电压;Collect current and/or voltage at the grid connection point of wind turbines in direct-drive wind farms;

或者,or,

直驱风电场中各直驱风机出口处的电流和/或电压。The current and/or voltage at the outlet of each direct-drive wind turbine in a direct-drive wind farm.

进一步,在所述振荡判断模块中,所述判断直驱风电场是否发生次/超同步振荡,包括:Further, in the oscillation judgment module, the judging whether sub-synchronous/super-synchronous oscillation occurs in the direct-driven wind farm includes:

若所述采集到的并网点处或任一直驱风机出口处的电流和/或电压的频率处于次/超同步振荡频率范围内,则判定直驱风电场发生次/超同步振荡。If the frequencies of the current and/or voltage collected at the grid connection point or at any outlet of the direct-driven wind turbine are within the sub/super synchronous oscillation frequency range, it is determined that sub/super synchronous oscillation occurs in the direct-driven wind farm.

进一步,所述次同步振荡频率范围为2.5-50Hz;所述超同步振荡频率范围为50-97.5Hz。Furthermore, the subsynchronous oscillation frequency range is 2.5-50 Hz; the supersynchronous oscillation frequency range is 50-97.5 Hz.

本发明的有益效果如下:The beneficial effects of the present invention are as follows:

本发明提供的基于锁相一致的直驱风电场振荡抑制方法,针对直驱风电场接入弱电网发生次/超同步频率振荡时,网侧变流器在传统锁相方式下风场内不同阻尼特性的风机间存在较大的动态能量交互,助增了次/超同步频率振荡的问题,提出了基于锁相一致的直驱风电场振荡抑制方法,并通过实例验证了该方法的正确性。与传统锁相方式相比,采用锁相一致技术后,正阻尼特性风机和负阻尼特性风机间的交互能量得到抑制,对直驱风电场的次/超同步频率振荡有显著的抑制效果。The direct-drive wind farm oscillation suppression method based on phase-locked consistency provided by the present invention aims at the problem that when the direct-drive wind farm is connected to a weak power grid and sub-/super-synchronous frequency oscillation occurs, there is a large dynamic energy interaction between wind turbines with different damping characteristics in the wind farm under the traditional phase-locked mode, which increases the sub-/super-synchronous frequency oscillation. The direct-drive wind farm oscillation suppression method based on phase-locked consistency is proposed, and the correctness of the method is verified through examples. Compared with the traditional phase-locked mode, after adopting the phase-locked consistency technology, the interactive energy between the wind turbines with positive damping characteristics and the wind turbines with negative damping characteristics is suppressed, which has a significant suppressive effect on the sub-/super-synchronous frequency oscillation of the direct-drive wind farm.

本发明提供的基于锁相一致的直驱风电场振荡抑制系统与上述方法基于基于相同的原理,其相关之处可相互借鉴,且能达到相同的技术效果。The direct-drive wind farm oscillation suppression system based on phase-locked consistency provided by the present invention is based on the same principle as the above method, and their related aspects can be mutually referenced, and the same technical effects can be achieved.

本发明中,上述各技术方案之间还可以相互组合,以实现更多的优选组合方案。本发明的其他特征和优点将在随后的说明书中阐述,并且,部分优点可从说明书中变得显而易见,或者通过实施本发明而了解。本发明的目的和其他优点可通过说明书、权利要求书以及附图中所特别指出的内容中来实现和获得。In the present invention, the above-mentioned technical solutions can also be combined with each other to achieve more preferred combination solutions. Other features and advantages of the present invention will be described in the subsequent description, and some advantages can become obvious from the description, or can be understood by practicing the present invention. The purpose and other advantages of the present invention can be achieved and obtained through the contents particularly pointed out in the description, claims and drawings.

附图说明BRIEF DESCRIPTION OF THE DRAWINGS

附图仅用于示出具体实施例的目的,而并不认为是对本发明的限制,在整个附图中,相同的参考符号表示相同的部件。The drawings are only for the purpose of illustrating particular embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like components throughout the drawings.

图1为基于锁相一致的直驱风电场振荡抑制方法流程图;FIG1 is a flow chart of a method for suppressing oscillations in a direct-drive wind farm based on phase-locked consistency;

图2为两机-无穷大系统参数模型;Figure 2 is a parameter model of a two-machine-infinity system;

图3为网侧变流器控制框图;Figure 3 is a control block diagram of the grid-side converter;

图4为锁相一致的两机-无穷大系统参数模型;Figure 4 is a parameter model of a two-machine-infinity system that is phase-locked;

图5为场景一锁相一致前后风场耗散能量对比;Figure 5 shows the comparison of wind field energy dissipation before and after phase-locking consistency in scenario 1;

图6为场景一锁相一致前后风机1电压电流;Figure 6 shows the voltage and current of fan 1 before and after phase locking in scenario 1;

图7为场景一传统锁相方式下两风机动态能量;Figure 7 shows the dynamic energy of two wind turbines in the traditional phase-locking mode in scenario 1;

图8为场景一锁相一致前后两风机交互动态能量;Figure 8 shows the interactive dynamic energy of the two wind turbines before and after phase locking in scenario 1;

图9为场景二锁相一致前后风场耗散能量对比;Figure 9 shows the comparison of wind field energy dissipation before and after phase locking in scenario 2;

图10为场景二锁相一致前后风机1电压电流;Figure 10 shows the voltage and current of fan 1 before and after the phase lock is consistent in scenario 2;

图11为场景二传统锁相方式下两风机动态能量;Figure 11 shows the dynamic energy of two wind turbines in the traditional phase-locking mode in scenario 2;

图12为场景二锁相一致前后两风机交互动态能量;Figure 12 shows the interactive dynamic energy of the two wind turbines before and after the phase lock is consistent in scenario 2;

图13为场景三锁相一致前后风场耗散能量对比;Figure 13 shows the comparison of wind field energy dissipation before and after the three-phase lock is consistent in the scenario;

图14为场景三锁相一致前后风机1电压电流Figure 14 shows the voltage and current of fan 1 before and after the three locks are consistent.

图15为场景三传统锁相方式下两风机动态能量Figure 15 shows the dynamic energy of two wind turbines in the traditional phase-locking mode in scenario 3

图16为场景三锁相一致前后两风机交互动态能量;Figure 16 shows the interactive dynamic energy of the two wind turbines before and after the three locks are consistent in the scene;

图17为基于锁相一致的直驱风电场振荡抑制系统结构示意图。FIG17 is a schematic diagram of the structure of a direct-drive wind farm oscillation suppression system based on phase-locked consistency.

具体实施方式DETAILED DESCRIPTION

下面结合附图来具体描述本发明的优选实施例,其中,附图构成本申请一部分,并与本发明的实施例一起用于阐释本发明的原理,并非用于限定本发明的范围。The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not used to limit the scope of the present invention.

实施例1Example 1

本发明的一个具体实施例,公开了一种基于锁相一致的直驱风电场振荡抑制方法,应用于风电场多机系统,流程图如图1所示,包括以下步骤:A specific embodiment of the present invention discloses a direct-drive wind farm oscillation suppression method based on phase-locked consistency, which is applied to a wind farm multi-machine system. The flow chart is shown in FIG1 and includes the following steps:

步骤S1:实时采集所述风电场多机系统的直驱风电场的电流和/或电压,判断直驱风电场是否发生次/超同步振荡;Step S1: collecting the current and/or voltage of the direct-drive wind farm of the wind farm multi-machine system in real time to determine whether sub-synchronous/super-synchronous oscillation occurs in the direct-drive wind farm;

步骤S2:若判断结果为发生,则调整风电场多机系统中各直驱风机锁相环输入端的电压为并网点的电压;Step S2: If the result of the judgment is that the event has occurred, the voltage at the input end of the phase-locked loop of each direct-drive wind turbine in the wind farm multi-machine system is adjusted to the voltage at the grid connection point;

其中,所述直驱风机锁相环连接在直驱风机出口处。Wherein, the direct-drive fan phase-locked loop is connected at the outlet of the direct-drive fan.

与现有技术相比,本实施例提供的基于锁相一致的直驱风电场振荡抑制方法,针对直驱风电场接入弱电网发生次/超同步频率振荡时,网侧变流器在传统锁相方式下风场内不同阻尼特性的风机间存在较大的动态能量交互,助增了次/超同步频率振荡的问题,提出了基于锁相一致的直驱风电场振荡抑制方法。与传统锁相方式相比,采用锁相一致技术后,正阻尼特性风机和负阻尼特性风机间的交互能量得到抑制,对直驱风电场的次/超同步频率振荡有显著的抑制效果。Compared with the prior art, the direct-drive wind farm oscillation suppression method based on phase-locked consistency provided in this embodiment is aimed at the problem that when the direct-drive wind farm is connected to a weak power grid and sub-/super-synchronous frequency oscillation occurs, there is a large dynamic energy interaction between wind turbines with different damping characteristics in the wind farm under the traditional phase-locked mode, which increases the sub-/super-synchronous frequency oscillation. A direct-drive wind farm oscillation suppression method based on phase-locked consistency is proposed. Compared with the traditional phase-locked mode, after adopting the phase-locked consistency technology, the interactive energy between the wind turbines with positive damping characteristics and the wind turbines with negative damping characteristics is suppressed, which has a significant suppressive effect on the sub-/super-synchronous frequency oscillation of the direct-drive wind farm.

上述方法中,直驱风机包括了依次连接的风力机、发电机、机侧变流器、网侧变流器,还包括了与网侧变流器相连的网侧变流器控制系统,具体结构可参考图2,其中,将网侧变流器的输出端作为直驱风机出口;多路直驱风机出口处均分别串联电抗,电抗的另一端相连形成并网点,由此构成了直驱风电场。In the above method, the direct-drive wind turbine includes a wind turbine, a generator, a machine-side converter, and a grid-side converter connected in sequence, and also includes a grid-side converter control system connected to the grid-side converter. The specific structure can be referred to Figure 2, wherein the output end of the grid-side converter is used as the outlet of the direct-drive wind turbine; reactances are respectively connected in series at the outlets of multiple direct-drive wind turbines, and the other ends of the reactances are connected to form a grid-connected point, thereby forming a direct-drive wind farm.

在上述方法的基础上,还可以包括如下步骤:On the basis of the above method, the following steps may also be included:

步骤S3:若判断结果为发生,实时检测次/超同步振荡是否结束,若结束,则所述各直驱风机锁相环输入端的电压恢复为与所述锁相环相连的直驱风机的输出端电压。Step S3: If the judgment result is that it occurs, it is detected in real time whether the sub/super synchronous oscillation is finished. If it is finished, the voltage at the input end of the phase-locked loop of each direct-drive fan is restored to the output end voltage of the direct-drive fan connected to the phase-locked loop.

优选地,所述实时采集直驱风电场的电流和/或电压为:采集直驱风电场中风机并网点处的电流和/或电压,或者,采集直驱风电场中各直驱风机出口处的电流和/或电压;此时,在步骤S1中,若所述采集到的并网点处或任一直驱风机出口处的电流和/或电压的频率处于次/超同步振荡频率范围内,则判定直驱风电场发生次/超同步振荡。Preferably, the real-time collection of the current and/or voltage of the direct-driven wind farm is: collecting the current and/or voltage at the grid-connected point of the wind turbine in the direct-driven wind farm, or collecting the current and/or voltage at the outlet of each direct-driven wind turbine in the direct-driven wind farm; at this time, in step S1, if the frequency of the collected current and/or voltage at the grid-connected point or at the outlet of any direct-driven wind turbine is within the sub-/super-synchronous oscillation frequency range, it is determined that sub-/super-synchronous oscillation occurs in the direct-driven wind farm.

优选地,本实施还给出了次/超同步振荡频率范围,以便本领域的技术人员根据该频率范围执行上述判断过程:所述次同步振荡频率范围为2.5-50Hz;所述超同步振荡频率范围为50-97.5Hz。Preferably, the present embodiment also provides a subsynchronous/supersynchronous oscillation frequency range, so that those skilled in the art can perform the above judgment process according to the frequency range: the subsynchronous oscillation frequency range is 2.5-50 Hz; the supersynchronous oscillation frequency range is 50-97.5 Hz.

本实施例步骤S2的调整过程,是基于以下分析得到的:The adjustment process of step S2 in this embodiment is obtained based on the following analysis:

一、建立考虑锁相环、网侧变流器的多机动态能量模型:1. Establish a multi-machine dynamic energy model considering phase-locked loop and grid-side converter:

在建立多机动态能量模型过程中,需要考虑作为该分析基础的实际物理模型,包括:多机-无穷大系统参数模型、网侧变流器控制模型;In the process of establishing the multi-machine dynamic energy model, it is necessary to consider the actual physical model that serves as the basis for the analysis, including: the multi-machine-infinity system parameter model, the grid-side converter control model;

本实施例以两机-无穷大系统参数模型为例,进行如下分析:如图2所示,在两机-无穷大系统参数模型中,风机1与风机2型号不同,接入并网点的线路电抗亦不同,接入同一并网点PCC,再经过一段输电线接入无穷大电网。其中,PMSG(Permanent MagnetSynchronous Generator)表示与风力机相连的发电机,VSC表示机侧变流器,GSC(GridSide Converter)表示网侧变流器,PLL(Phase-locked loop)表示锁相环;This embodiment takes the two-machine-infinite system parameter model as an example and performs the following analysis: As shown in Figure 2, in the two-machine-infinite system parameter model, wind turbine 1 and wind turbine 2 are of different models, and the line reactances of the grid-connected points are also different. They are connected to the same grid-connected point PCC and then connected to the infinite power grid through a section of transmission line. Among them, PMSG (Permanent Magnet Synchronous Generator) represents the generator connected to the wind turbine, VSC represents the machine-side converter, GSC (Grid Side Converter) represents the grid-side converter, and PLL (Phase-locked loop) represents the phase-locked loop;

所述两机-无穷大系统参数模型端口(指风机端口)电压方程可以表示为:The voltage equation of the port (referring to the fan port) of the two-machine-infinity system parameter model can be expressed as:

ud1=udPCC-X1iq1 (1)u d1 = u dPCC -X 1 i q1 (1)

uq1=uqPCC+X1id1 (2)u q1 = u qPCC + X 1 i d1 (2)

ud2=udPCC-X2iq2 (3)u d2 = u dPCC -X 2 i q2 (3)

uq2=uqPCC+X2id2 (4)u q2 =u qPCC +X 2 i d2 (4)

根据公式(1)-(4),可推导出公式(5)、(6):According to formulas (1)-(4), formulas (5) and (6) can be derived:

uq1=uq2-X2id2+X1id1 (5)u q1 =u q2 -X 2 i d2 +X 1 i d1 (5)

ud1=ud2+X2iq2-X1iq1 (6)u d1 =u d2 +X 2 i q2 -X 1 i q1 (6)

式中:ud1、uq1、id1、iq1分别表示风机1端口在d轴、q轴上的电压和电流;ud2、uq2、id2、iq2分别表示风机2端口在d轴、q轴上的电压和电流;udPCC、uqPCC分别表示并网点PCC处在d轴、q轴上的电压;X1、X2分别表示风机1、风机2接入并网点PCC的线路电抗。In the formula: u d1 , u q1 , i d1 , i q1 represent the voltage and current of the port of wind turbine 1 on the d-axis and q-axis respectively; u d2 , u q2 , i d2 , i q2 represent the voltage and current of the port of wind turbine 2 on the d-axis and q-axis respectively; u dPCC , u qPCC represent the voltage of the grid-connected point PCC on the d-axis and q-axis respectively; X 1 , X 2 represent the line reactance of wind turbine 1 and wind turbine 2 connected to the grid-connected point PCC respectively.

如图3所示为所述网侧变流器控制模型框图。网侧变流器控制模型的输出电压可以表示为(这里的输出电压即为网侧变流器GSC的输出电压,也是两机-无穷大系统参数模型的端口电压):FIG3 is a block diagram of the grid-side converter control model. The output voltage of the grid-side converter control model can be expressed as (the output voltage here is the output voltage of the grid-side converter GSC, which is also the port voltage of the two-machine-infinity system parameter model):

Figure BDA0002342498700000081
Figure BDA0002342498700000081

Figure BDA0002342498700000082
Figure BDA0002342498700000082

式中:Kp、Ki分别为网侧变流器控制系统电流内环的比例、积分系数;

Figure BDA0002342498700000083
分别为网侧变流器控制系统的d轴、q轴电流参考值;ω为并网点PCC的电压角频率;L为进线电抗器感抗;Eg为并网点PCC的电压幅值。Where: K p and Ki are the proportional and integral coefficients of the current inner loop of the grid-side converter control system respectively;
Figure BDA0002342498700000083
are the d-axis and q-axis current reference values of the grid-side converter control system respectively; ω is the voltage angular frequency of the grid-connected point PCC; L is the inductive reactance of the incoming line reactor; Eg is the voltage amplitude of the grid-connected point PCC.

经过上述分析,多机动态能量模型可表示为:After the above analysis, the multi-machine dynamic energy model can be expressed as:

W=W1+W2 (9)W=W 1 +W 2 (9)

式中:W表示多机动态能量流,W1和W2表示风机1和风机2的网侧变流器出口处动态能量流。Where: W represents the dynamic energy flow of multiple machines, W1 and W2 represent the dynamic energy flow at the outlet of the grid-side converter of wind turbine 1 and wind turbine 2.

其中,风机网侧变流器出口处动态能量流可以表示为:Among them, the dynamic energy flow at the outlet of the wind turbine grid-side converter can be expressed as:

Figure BDA0002342498700000084
Figure BDA0002342498700000084

Figure BDA0002342498700000091
Figure BDA0002342498700000091

式中:Pe为风机端口的有功功率,θ为风机端口的功角,Wp=∫Pedθ表示风机有功功率对应的变流器出口处的端口动态能量流,Wq=∫(idduq-iqdud)为该直驱风电机组无功功率对应的变流器出口处的端口动态能量流;下标1、2分别表示风机1和风机2网侧变流器出口处。In the formula: Pe is the active power of the wind turbine port, θ is the power angle of the wind turbine port, Wp = ∫Pedθ represents the port dynamic energy flow at the converter outlet corresponding to the active power of the wind turbine, Wq = ∫(idduq-iqdud ) is the port dynamic energy flow at the converter outlet corresponding to the reactive power of the direct-drive wind turbine set; subscripts 1 and 2 represent the grid-side converter outlets of wind turbine 1 and wind turbine 2, respectively.

二、提取动态能量流中的非周期变化分量,将其定义为耗散能量,分析影响耗散能量大小的关键因素,求解耗散能量最小值的条件,并以此条件提出基于锁相一致的直驱风电场振荡抑制方法。Second, extract the non-periodic changing component in the dynamic energy flow, define it as dissipated energy, analyze the key factors affecting the size of the dissipated energy, solve the conditions for the minimum value of the dissipated energy, and propose an oscillation suppression method for direct-driven wind farms based on phase-locked consistency based on this condition.

在上述过程中,可具体包括以下几步:The above process may specifically include the following steps:

(1):提取动态能量流中的非周期分量耗散能量。(1): Extract the non-periodic component dissipated energy in the dynamic energy flow.

直驱风电场发生单一振荡模态的次/超同步频率振荡时,网侧变流器输出的三相电流包括基波电流分量、次/超同步频率电流分量和超同步电流分量,则A相电压ua、电流ia可表示为:When a sub/super synchronous frequency oscillation of a single oscillation mode occurs in a direct-drive wind farm, the three-phase current output by the grid-side converter includes a fundamental current component, a sub/super synchronous frequency current component, and a super synchronous current component. The A-phase voltage u a and current ia can be expressed as:

Figure BDA0002342498700000092
Figure BDA0002342498700000092

式中:下标0、-和+分别表示基波、次/超同步频率和超同步;u0、i0为基波电压、电流分量幅值;u_、i_为次/超同步频率电压、电流分量幅值;u+、i+为超同步电压、电流分量幅值;ω0、ω-和ω+分别为基波、次同步和超同步电压角频率;

Figure BDA0002342498700000101
为初相角。Wherein: subscripts 0, - and + represent fundamental, sub/super synchronous frequency and super synchronous respectively; u 0 , i 0 are the amplitudes of fundamental voltage and current components; u _ , i _ are the amplitudes of sub/super synchronous frequency voltage and current components; u + , i + are the amplitudes of super synchronous voltage and current components; ω 0 , ω - and ω + are the fundamental, sub synchronous and super synchronous voltage angular frequencies respectively;
Figure BDA0002342498700000101
is the initial phase angle.

锁相环输入相角θ与锁相环向电流内环控制模块输出的相角θ′的关系为:The relationship between the phase angle θ of the phase-locked loop input and the phase angle θ′ output by the phase-locked loop to the current inner loop control module is:

θ′=θ+ΔθPLL (13)θ′=θ+Δθ PLL (13)

式中,

Figure BDA0002342498700000102
为锁相环不能完全跟踪电网相位信息产生的扰动分量,A和
Figure BDA0002342498700000103
分别为锁相环扰动角ΔθPLL的幅值和初相位;ωσ=ω0-,其中,ω0表示网侧变流器输出的电压基波角频率;ωs表示网侧变流器输出的次同步电压角频率;In the formula,
Figure BDA0002342498700000102
is the disturbance component caused by the phase-locked loop’s inability to fully track the grid phase information, A and
Figure BDA0002342498700000103
are the amplitude and initial phase of the phase-locked loop disturbance angle Δθ PLL respectively; ω σ0- , where ω 0 represents the voltage fundamental angular frequency output by the grid-side converter; ω s represents the sub-synchronous voltage angular frequency output by the grid-side converter;

锁相环扰动角ΔθPLL的数值很小,实际计算中可简化为cos(ΔθPLL)≈1、sin(ΔθPLL)≈ΔθPLLThe value of the phase-locked loop disturbance angle Δθ PLL is very small and can be simplified to cos(Δθ PLL )≈1 and sin(Δθ PLL )≈Δθ PLL in actual calculation.

从电网abc坐标系转化到网侧变流器dq坐标系的变换矩阵为:The transformation matrix from the grid abc coordinate system to the grid-side converter dq coordinate system is:

Figure BDA0002342498700000104
Figure BDA0002342498700000104

考虑锁相环不能完全跟踪时的风机端口电压电流可表示为:Considering that the phase-locked loop cannot fully track the fan port voltage and current, it can be expressed as:

Figure BDA0002342498700000105
Figure BDA0002342498700000105

Figure BDA0002342498700000106
Figure BDA0002342498700000106

Figure BDA0002342498700000107
Figure BDA0002342498700000108
Figure BDA0002342498700000107
Figure BDA0002342498700000108

将上述电流电压公式代入步骤1得到的动态能量公式,再提取其非周期分量为风机耗散能量Whq1为:Substitute the above current and voltage formula into the dynamic energy formula obtained in step 1, and then extract its non-periodic component as the fan dissipated energy W hq1 :

Figure BDA0002342498700000111
Figure BDA0002342498700000111

式中,

Figure BDA0002342498700000112
ωσ=ω0-=ω+0;Δαu-=αu2-u1-为风机2与风机1的锁相角次/超同步频率分量的相角差;Δαu+=αu2+u1+为风机2与风机1的锁相角超同步频率分量相角差;
Figure BDA0002342498700000113
Δβ=β21为风机2与风机1的锁相环扰动角ΔθPLL的相角β的相角差。In the formula,
Figure BDA0002342498700000112
ω σ =ω 0- =ω +0 ; Δα u- =α u2-u1- is the phase angle difference of the phase-locking angle/super-synchronous frequency component between fan 2 and fan 1; Δα u+ =α u2+u1+ is the phase angle difference of the phase-locking angle super-synchronous frequency component between fan 2 and fan 1;
Figure BDA0002342498700000113
Δβ=β 21 is the phase angle difference β between the phase-locked loop disturbance angle Δθ PLL of fan 2 and fan 1.

式中直驱风电机组有功功率对应的端口动态能量Wp1,由于Wp1中的有功功率Pe1由风速决定,所以Whp1与锁相环的锁相角和锁相环扰动角ΔθPLL的相角无关。其对应的耗散能量可表示为Whp1In the formula, the port dynamic energy corresponding to the active power of the direct-drive wind turbine is W p1 . Since the active power P e1 in W p1 is determined by the wind speed, W hp1 is independent of the phase-locked loop phase angle and the phase-locked loop disturbance angle Δθ PLL . The corresponding dissipated energy can be expressed as W hp1 .

同理,亦可得到风机2网侧变流器出口处的无功功率对应的耗散能量Whq2和有功功率对应的耗散能量Whp2。其中,Whq2为:Similarly, the dissipated energy W hq2 corresponding to the reactive power and the dissipated energy W hp2 corresponding to the active power at the outlet of the grid-side converter of wind turbine 2 can also be obtained. Where, W hq2 is:

Figure BDA0002342498700000114
Figure BDA0002342498700000114

式中,

Figure BDA0002342498700000115
In the formula,
Figure BDA0002342498700000115

于是,该两机-无穷大系统的总耗散能量为:Therefore, the total dissipated energy of the two-machine-infinity system is:

Wh=(Whq1+Whq2)+(Whp1+Whp2) (19)W h =(W hq1 +W hq2 )+(W hp1 +W hp2 ) (19)

式中,Whp1、Whp2与其锁相环的锁相角及锁相环扰动角的相角β均无关。Wherein, W hp1 and W hp2 are independent of the phase-locked angle of their phase-locked loop and the phase angle β of the phase-locked loop disturbance angle.

(2):分析影响耗散能量大小的关键因素,求解耗散能量最小值的条件,并以此条件提出基于锁相一致的直驱风电场振荡抑制方法。(2) Analyze the key factors that affect the amount of dissipated energy, solve the conditions for the minimum dissipated energy, and propose an oscillation suppression method for direct-drive wind farms based on phase-locked consistency based on this condition.

系统次/超同步频率振荡时产生的耗散能量代表动态能量的变化趋势,耗散能量越小,对振荡抑制越有利。由于两风机接入并网点的线路电抗不同(即X1≠X2),风机1与风机2的网侧变流器出口处电压相角将产生相位差(即Δαu-=αu2-u1-≠0Δαu+=αu2+u1+≠0);又因为两风机使用两个锁相环,其性能不完全一致,两锁相环动态角的相角差不等于零(即Δβ=β21≠0)。Δαu-、Δαu+和Δβ不等于零,总耗散能量受其影响较大,影响了次/超同步频率振荡时系统的稳定域。The dissipated energy generated when the system is in sub/super synchronous frequency oscillation represents the changing trend of dynamic energy. The smaller the dissipated energy, the more favorable it is for oscillation suppression. Since the line reactances of the two wind turbines connected to the grid are different (i.e., X 1 ≠X 2 ), the voltage phase angles at the outlets of the grid-side converters of wind turbines 1 and 2 will have a phase difference (i.e., Δα u- =α u2-u1- ≠0Δα u+ =α u2+u1+ ≠0); and because the two wind turbines use two phase-locked loops, their performance is not completely consistent, and the phase angle difference of the dynamic angles of the two phase-locked loops is not equal to zero (i.e., Δβ=β 21 ≠0). Δα u- , Δα u+ and Δβ are not equal to zero, and the total dissipated energy is greatly affected by them, which affects the stability domain of the system during sub/super synchronous frequency oscillation.

Wh是Δαu-、Δαu+和Δβ的函数,可表示为函数Wh(Δαu-,Δαu+,Δβ),分别对Δαu-、Δαu+和Δβ求导可得:W h is a function of Δα u- , Δα u+ and Δβ, and can be expressed as function W h (Δα u- , Δα u+ , Δβ). By taking the derivatives of Δα u- , Δα u+ and Δβ respectively, we can obtain:

Figure BDA0002342498700000121
Figure BDA0002342498700000121

Figure BDA0002342498700000122
Figure BDA0002342498700000122

Figure BDA0002342498700000123
Figure BDA0002342498700000123

式中,

Figure BDA0002342498700000124
In the formula,
Figure BDA0002342498700000124

Figure BDA0002342498700000131
求出函数Wh的唯一驻点为:(Δαu-,Δαu+,Δβ)=(0,0,0),建立三元函数求极值的Hessian阵[H]:make
Figure BDA0002342498700000131
The only stationary point of the function W h is found to be: (Δα u- , Δα u+ , Δβ) = (0, 0, 0), and the Hessian matrix [H] for finding the extreme value of the ternary function is established:

Figure BDA0002342498700000132
Figure BDA0002342498700000132

Figure BDA0002342498700000133
Figure BDA0002342498700000133

Figure BDA0002342498700000134
Figure BDA0002342498700000134

Figure BDA0002342498700000135
Figure BDA0002342498700000135

Figure BDA0002342498700000136
Figure BDA0002342498700000136

Figure BDA0002342498700000137
Figure BDA0002342498700000137

Figure BDA0002342498700000138
Figure BDA0002342498700000138

|H|=∫2B3A1A2(2+A1A2)u1-u2-u1+u2+(u1+u2+-u1-u2-)dt (30)|H|=∫2B 3 A 1 A 2 (2+A 1 A 2 )u 1- u 2- u 1+ u 2+ (u 1+ u 2+ -u 1- u 2- )dt (30)

由于直驱风电场次/超同步频率振荡中,超同步电压总是大于次/超同步频率电压,所以u1+u2+-u1-u2->0,从而式中|H|>0。又因为

Figure BDA0002342498700000141
系统总耗散能量Wh(Δαu-,Δαu+,Δβ)在点(Δαu-,Δαu+,Δβ)=(0,0,0)处取得最小值,直驱风电场次/超同步频率振荡抑制效果最优。由此,提出了一种基于锁相一致的直驱风电场次/超同步频率振荡抑制方法。Since the super synchronous voltage is always greater than the sub/super synchronous voltage in the direct-drive wind farm sub/super synchronous frequency oscillation, u 1+ u 2+ -u 1- u 2- >0, so |H|>0. And because
Figure BDA0002342498700000141
The total dissipated energy of the system W h (Δα u- , Δα u+ , Δβ) reaches the minimum value at the point (Δα u- , Δα u+ , Δβ) = (0, 0, 0), and the direct-driven wind farm/super-synchronous frequency oscillation suppression effect is optimal. Therefore, a direct-driven wind farm/super-synchronous frequency oscillation suppression method based on phase-locked consistency is proposed.

图4所示为锁相一致的直驱风电场的两机-无穷大系统。采用并网点锁相一致技术,即:风电场并网点(点PCC)处安装锁相环,两风机网侧变流器控制系统均取该锁相环相角为参考相角。Figure 4 shows a two-machine-infinity system of a direct-drive wind farm with consistent phase locking. The grid-connected point phase-locked consistency technology is adopted, that is, a phase-locked loop is installed at the wind farm grid-connected point (point PCC), and the control systems of the two wind turbine grid-side converters both take the phase angle of the phase-locked loop as the reference phase angle.

基于锁相一致技术,风机端口电流电压可表示为:Based on the phase-locked consistency technology, the fan port current and voltage can be expressed as:

Figure BDA0002342498700000142
Figure BDA0002342498700000142

Figure BDA0002342498700000143
Figure BDA0002342498700000143

Figure BDA0002342498700000144
Figure BDA0002342498700000144

Figure BDA0002342498700000145
Figure BDA0002342498700000145

基于锁相一致技术,提取耗散能量为:Based on the phase-locked consistent technology, the dissipated energy is extracted as:

Figure BDA0002342498700000151
Figure BDA0002342498700000151

Figure BDA0002342498700000152
Figure BDA0002342498700000152

风场内风机取同一并网点(点PCC)的锁相环相角,不影响两风机有功功率对应的耗散能量;于是,该两机-无穷大系统的总耗散能量为:The wind turbines in the wind farm take the same phase-locked loop phase angle of the grid connection point (point PCC), which does not affect the dissipated energy corresponding to the active power of the two wind turbines; therefore, the total dissipated energy of the two-machine-infinity system is:

W′h=(W′hq1+W′hq2)+(Whp1+Whp2) (37)W′ h =(W′ hq1 +W′ hq2 )+(W hp1 +W hp2 ) (37)

对比可知,风场采用锁相一致技术后,风机的耗散能量中由不同风机相角差及锁相角动态产生的交互能量被抑制,风场总耗散能量减小,由此,风场的次/超同步频率振荡得到抑制。By comparison, it can be seen that after the wind farm adopts the phase-locked consistency technology, the interactive energy generated by the phase angle difference and phase-locked angle dynamics of different wind turbines in the dissipated energy of the wind turbine is suppressed, and the total dissipated energy of the wind farm is reduced. As a result, the sub/supersynchronous frequency oscillation of the wind farm is suppressed.

实施例2Example 2

本实施例为时域仿真验证过程:在本实施例中,根据上述方法,求取了动态能量和耗散能量以验证理论的正确性。实际应用时不需要求取耗散能量,只需要判断是否发生振荡,若发生,采取振荡抑制措施,即调整锁相环控制策略为锁相一致。This embodiment is a time domain simulation verification process: In this embodiment, according to the above method, dynamic energy and dissipated energy are obtained to verify the correctness of the theory. In actual application, it is not necessary to obtain dissipated energy, but only to determine whether oscillation occurs. If so, take oscillation suppression measures, that is, adjust the phase-locked loop control strategy to be phase-locked consistent.

如图2所示两机-无穷大系统参数模型。不失一般性,仿真中设定风机1出力大于风机2,两风机接入并网点线路电抗不相等。参数如表1所示:The parameter model of the two-machine-infinity system is shown in Figure 2. Without loss of generality, the output of wind turbine 1 is set to be greater than that of wind turbine 2 in the simulation, and the line reactances of the two wind turbines connected to the grid are not equal. The parameters are shown in Table 1:

表1直驱风机接入弱电网系统主要参数Table 1 Main parameters of direct-drive wind turbine connected to weak grid system

Figure BDA0002342498700000153
Figure BDA0002342498700000153

Figure BDA0002342498700000161
Figure BDA0002342498700000161

时域仿真验证过程设定了三种振荡场景的仿真验证:振荡发散、等幅振荡和振荡发散。The time domain simulation verification process sets up simulation verification of three oscillation scenarios: oscillation divergence, equal amplitude oscillation and oscillation divergence.

两机-无穷大系统使用传统锁相方式时,在某运行状态下发生次/超同步频率振荡发散(等幅振荡或振荡发散),测量该系统的运行状态;同一次/超同步频率振荡下,3秒时切换锁相方式为并网点锁相一致,测量该系统此时的运行状态。When the two-machine-infinity system uses the traditional phase-locking method, sub/supersynchronous frequency oscillation divergence (equal amplitude oscillation or oscillation divergence) occurs under a certain operating state, and the operating state of the system is measured; under the same sub/supersynchronous frequency oscillation, the phase-locking method is switched to the grid-connected point phase-locking consistency at 3 seconds, and the operating state of the system at this time is measured.

图5-16中,Wind1和Wind2表示风机1和风机2;PLLdiff表示传统锁相方式,PLLsame表示使用锁相一致技术。In Figure 5-16, Wind1 and Wind2 represent fan 1 and fan 2; PLLdiff represents the traditional phase-locking method, and PLLsame represents the use of phase-locking consistency technology.

场景一:由图5可知,锁相一致前,耗散能量曲线为凹曲线,耗散能量不断增大,振荡逐步加剧;锁相一致后,耗散能量曲线为凸曲线,耗散能量增加逐渐减小,振荡逐步收敛。锁相一致后风场耗散能量小于传统锁相方式,次/超同步频率振荡得到抑制。由图6可知,锁相一致前,风机1振荡发散;锁相一致后,风机1逐渐收敛;锁相一致对次/超同步频率振荡的抑制作用明显。Scenario 1: As shown in Figure 5, before phase locking, the dissipated energy curve is a concave curve, the dissipated energy continues to increase, and the oscillation gradually intensifies; after phase locking, the dissipated energy curve is a convex curve, the dissipated energy increase gradually decreases, and the oscillation gradually converges. After phase locking, the wind farm dissipated energy is less than the traditional phase locking method, and the sub/super synchronous frequency oscillation is suppressed. As shown in Figure 6, before phase locking, the oscillation of wind turbine 1 diverges; after phase locking, wind turbine 1 gradually converges; phase locking has a significant inhibitory effect on sub/super synchronous frequency oscillations.

由图7可知,该运行状态下,直驱风电场接入弱电网发生次/超同步频率振荡时,风机1发出动态能量,而风机2吸收动态能量,两风机间存在较大的能量交互;风机1表现为正阻尼机组,风机2表现为负阻尼机组,风场内风机的振荡情况十分复杂。由图8可知,锁相一致前,风机间动态能量交互作用不断增大;而锁相一致后,风机间交互能量很小,场内风机能量流的助增作用得到抑制。As shown in Figure 7, in this operating state, when the direct-drive wind farm is connected to a weak grid and sub-/super-synchronous frequency oscillation occurs, wind turbine 1 emits dynamic energy, while wind turbine 2 absorbs dynamic energy, and there is a large energy interaction between the two wind turbines; wind turbine 1 behaves as a positive damping unit, and wind turbine 2 behaves as a negative damping unit, and the oscillation of the wind turbines in the wind farm is very complex. As shown in Figure 8, before the phase lock is consistent, the dynamic energy interaction between the wind turbines continues to increase; after the phase lock is consistent, the interactive energy between the wind turbines is very small, and the boosting effect of the energy flow of the wind turbines in the field is suppressed.

场景二:由图9可知,锁相一致前,风电场的耗散能量曲线为一条直线,持续发出耗散耗散能量,系统发生次/超同步频率振荡;而锁相一致后,耗散能量为凹曲线,且耗散能量小于传统锁相,系统稳定性更高。由图10可知,锁相一致前,风电场发生等幅振荡,锁相一致后,风电场次/超同步振荡收敛,系统运行逐渐稳定。Scenario 2: As shown in Figure 9, before the phase lock is consistent, the dissipated energy curve of the wind farm is a straight line, and the dissipated energy is continuously emitted, and the system has sub/super synchronous frequency oscillations; after the phase lock is consistent, the dissipated energy is a concave curve, and the dissipated energy is less than the traditional phase lock, and the system stability is higher. As shown in Figure 10, before the phase lock is consistent, the wind farm has equal amplitude oscillations, and after the phase lock is consistent, the wind farm sub/super synchronous oscillations converge, and the system operation gradually stabilizes.

由图11和图12可知,锁相一致后,两风机动态能量均为正,两风机间没有交互能量。It can be seen from Figures 11 and 12 that after the phase locking is consistent, the dynamic energy of the two fans is positive, and there is no interactive energy between the two fans.

场景三:由图13可知,锁相一致前后,风场的耗散能量曲线均为凸曲线,系统趋于稳定;由图14可知,在该场景下风场发生次/超同步频率振荡并振荡收敛;锁相一致后,风场振荡收敛,振荡强度减弱,收敛速度明显加快。而锁相一致后,耗散能量小于传统锁相,系统稳定性更好。如图15所示,传统锁相方式下,两风机均发出动态能量,场内无动态能量交互;如图16所示,锁相一致后,风机间亦没有能量交互,并且发出的动态能量减小,振荡强度明显减弱。Scenario 3: As shown in Figure 13, before and after phase locking, the dissipated energy curves of the wind farm are convex curves, and the system tends to be stable; as shown in Figure 14, in this scenario, the wind farm has sub/supersynchronous frequency oscillations and the oscillations converge; after phase locking, the wind farm oscillations converge, the oscillation intensity weakens, and the convergence speed is significantly accelerated. After phase locking, the dissipated energy is less than the traditional phase locking, and the system stability is better. As shown in Figure 15, under the traditional phase locking method, both wind turbines emit dynamic energy, and there is no dynamic energy interaction in the field; as shown in Figure 16, after phase locking, there is no energy interaction between wind turbines, and the dynamic energy emitted is reduced, and the oscillation intensity is significantly weakened.

由此可知,采用锁相一致技术较采用传统锁相技术,系统发生次/超同步频率振荡后发出的耗散能量曲线由凸曲线变为凹曲线,且其量值减小显著,增大了系统稳定裕度;正阻尼特性风机和负阻尼特性风机间的交互能量得到抑制,风场对外发出的动态能量显著减小,振荡强度减弱;风电场由振荡发散变为振荡收敛,对直驱风电场的次/超同步频率振荡有显著的抑制效果。It can be seen that when the phase-locked consistency technology is used, compared with the traditional phase-locked technology, the dissipated energy curve emitted by the system after sub/supersynchronous frequency oscillation occurs changes from a convex curve to a concave curve, and its value decreases significantly, thereby increasing the system stability margin; the interaction energy between the positive damping characteristic wind turbine and the negative damping characteristic wind turbine is suppressed, the dynamic energy emitted by the wind farm to the outside is significantly reduced, and the oscillation intensity is weakened; the wind farm changes from oscillation divergence to oscillation convergence, which has a significant inhibitory effect on the sub/supersynchronous frequency oscillation of the direct-drive wind farm.

实施例3Example 3

在本发明的实施例3中,公开了一种基于锁相一致的直驱风电场振荡抑制系统,结构示意图如图17所示,应用于风电场多机系统,该系统包括以下模块:In Embodiment 3 of the present invention, a direct-drive wind farm oscillation suppression system based on phase-locked consistency is disclosed, the structural schematic diagram of which is shown in FIG17 and is applied to a wind farm multi-machine system. The system includes the following modules:

数据采集模块,用于实时采集所述风电场多机系统的直驱风电场的电流和/或电压;振荡判断模块,用于接收所述数据采集模块采集到的数据,并判断直驱风电场是否发生次/超同步振荡;振荡抑制模块,用于当所述振荡判断模块的判断结果为发生时,调整风电场多机系统中各直驱风机锁相环输入端的电压为并网点的电压;其中,所述直驱风机锁相环连接在直驱风机出口处。A data acquisition module is used to collect the current and/or voltage of the direct-driven wind farm of the multi-machine system of the wind farm in real time; an oscillation judgment module is used to receive the data collected by the data acquisition module and judge whether sub-synchronous/super-synchronous oscillation occurs in the direct-driven wind farm; an oscillation suppression module is used to adjust the voltage of the phase-locked loop input terminal of each direct-driven wind turbine in the multi-machine system of the wind farm to the voltage of the grid connection point when the judgment result of the oscillation judgment module is that it occurs; wherein the direct-driven wind turbine phase-locked loop is connected at the outlet of the direct-driven wind turbine.

优选地,所述系统还包括:振荡恢复模块,用于当所述振荡判断模块的判断结果为发生时,控制所述数据采集模块和所述振荡判断模块实时检测次/超同步振荡是否结束,若结束,则所述各直驱风机锁相环输入端的电压恢复为与所述锁相环相连的直驱风机的输出端电压。Preferably, the system also includes: an oscillation recovery module, which is used to control the data acquisition module and the oscillation judgment module to detect in real time whether the sub/super synchronous oscillation has ended when the judgment result of the oscillation judgment module is that the oscillation has occurred. If it has ended, the voltage at the input end of the phase-locked loop of each direct-drive fan is restored to the output end voltage of the direct-drive fan connected to the phase-locked loop.

上述方法实施例和系统实施例,基于相同的原理,其相关之处可相互借鉴,且能达到相同的技术效果。The above method embodiments and system embodiments are based on the same principle, and their related parts can be referenced from each other and can achieve the same technical effects.

本领域技术人员可以理解,实现上述实施例方法的全部或部分流程,可以通过计算机程序来指令相关的硬件来完成,所述的程序可存储于计算机可读存储介质中。其中,所述计算机可读存储介质为磁盘、光盘、只读存储记忆体或随机存储记忆体等。Those skilled in the art will appreciate that all or part of the processes of the above-mentioned embodiments can be implemented by instructing related hardware through a computer program, and the program can be stored in a computer-readable storage medium, wherein the computer-readable storage medium is a disk, an optical disk, a read-only storage memory, or a random access memory, etc.

以上所述,仅为本发明较佳的具体实施方式,但本发明的保护范围并不局限于此,任何熟悉本技术领域的技术人员在本发明揭露的技术范围内,可轻易想到的变化或替换,都应涵盖在本发明的保护范围之内。The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims (6)

1.一种基于锁相一致的直驱风电场振荡抑制方法,应用于风电场多机系统,其特征在于,所述方法包括如下步骤:1. A direct-drive wind farm oscillation suppression method based on phase-locked consistency, applied to a wind farm multi-machine system, characterized in that the method comprises the following steps: 将直驱风机中网侧变流器的输出端作为直驱风机出口,直驱风机锁相环连接在直驱风机出口处;The output end of the grid-side converter in the direct-drive fan is used as the outlet of the direct-drive fan, and the direct-drive fan phase-locked loop is connected to the outlet of the direct-drive fan; 实时采集所述风电场多机系统的直驱风电场的电流和/或电压,判断直驱风电场是否发生次/超同步振荡;所述实时采集直驱风电场的电流和/或电压为:直驱风电场中风机并网点处的电流和/或电压;或者,直驱风电场中各直驱风机出口处的电流和/或电压;The current and/or voltage of the direct-driven wind farm of the wind farm multi-machine system is collected in real time to determine whether sub-synchronous/super-synchronous oscillation occurs in the direct-driven wind farm; the current and/or voltage of the direct-driven wind farm collected in real time is: the current and/or voltage at the grid connection point of the wind turbine in the direct-driven wind farm; or the current and/or voltage at the outlet of each direct-driven wind turbine in the direct-driven wind farm; 若判断结果为发生,则调整风电场多机系统中各直驱风机锁相环输入端的电压为并网点的电压,使锁相环控制策略为锁相一致;If the result of the judgment is that it has occurred, the voltage at the input end of the phase-locked loop of each direct-drive wind turbine in the wind farm multi-machine system is adjusted to the voltage at the grid connection point, so that the phase-locked loop control strategy is phase-locked consistent; 所述方法还包括:The method further comprises: 若判断结果为发生,实时检测次/超同步振荡是否结束,若结束,则所述各直驱风机锁相环输入端的电压恢复为与所述锁相环相连的直驱风机的输出端电压。If the judgment result is that it occurs, it is detected in real time whether the sub/super synchronous oscillation is ended. If it is ended, the voltage at the input end of the phase-locked loop of each direct-drive fan is restored to the output end voltage of the direct-drive fan connected to the phase-locked loop. 2.根据权利要求1所述的基于锁相一致的直驱风电场振荡抑制方法,其特征在于,所述判断直驱风电场是否发生次/超同步振荡,包括:2. The method for suppressing oscillation of a direct-driven wind farm based on phase-locked consistency according to claim 1, characterized in that the step of judging whether sub-synchronous or super-synchronous oscillation occurs in the direct-driven wind farm comprises: 若所述采集到的并网点处或任一直驱风机出口处的电流和/或电压的频率处于次/超同步振荡频率范围内,则判定直驱风电场发生次/超同步振荡。If the frequencies of the current and/or voltage collected at the grid connection point or at any outlet of the direct-driven wind turbine are within the sub/super synchronous oscillation frequency range, it is determined that sub/super synchronous oscillation occurs in the direct-driven wind farm. 3.根据权利要求2所述的基于锁相一致的直驱风电场振荡抑制方法,其特征在于,所述次同步振荡频率范围为2.5-50Hz;所述超同步振荡频率范围为50-97.5Hz。3. The direct-drive wind farm oscillation suppression method based on phase-locked consistency according to claim 2 is characterized in that the subsynchronous oscillation frequency range is 2.5-50 Hz; the supersynchronous oscillation frequency range is 50-97.5 Hz. 4.一种基于锁相一致的直驱风电场振荡抑制系统,应用于风电场多机系统,其特征在于,所述系统包括:4. A direct-drive wind farm oscillation suppression system based on phase-locked consistency, applied to a wind farm multi-machine system, characterized in that the system comprises: 将直驱风机中网侧变流器的输出端作为直驱风机出口,直驱风机锁相环连接在直驱风机出口处;The output end of the grid-side converter in the direct-drive fan is used as the outlet of the direct-drive fan, and the direct-drive fan phase-locked loop is connected to the outlet of the direct-drive fan; 数据采集模块,用于实时采集所述风电场多机系统的直驱风电场的电流和/或电压;所述实时采集直驱风电场的电流和/或电压为:直驱风电场中风机并网点处的电流和/或电压;或者,直驱风电场中各直驱风机出口处的电流和/或电压;A data acquisition module, used for real-time acquisition of the current and/or voltage of the direct-driven wind farm of the wind farm multi-machine system; the real-time acquisition of the current and/or voltage of the direct-driven wind farm is: the current and/or voltage at the grid connection point of the wind turbine in the direct-driven wind farm; or the current and/or voltage at the outlet of each direct-driven wind turbine in the direct-driven wind farm; 振荡判断模块,用于接收所述数据采集模块采集到的数据,并判断直驱风电场是否发生次/超同步振荡;An oscillation judgment module, used for receiving the data collected by the data collection module and judging whether sub-synchronous/super-synchronous oscillation occurs in the direct-driven wind farm; 振荡抑制模块,用于当所述振荡判断模块的判断结果为发生时,调整风电场多机系统中各直驱风机锁相环输入端的电压为并网点的电压,使锁相环控制策略为锁相一致;An oscillation suppression module, used for adjusting the voltage of the phase-locked loop input terminal of each direct-drive wind turbine in the wind farm multi-machine system to the voltage of the grid connection point when the judgment result of the oscillation judgment module is that the oscillation occurs, so that the phase-locked loop control strategy is phase-locked consistent; 所述系统还包括:The system further comprises: 振荡恢复模块,用于当所述振荡判断模块的判断结果为发生时,控制所述数据采集模块和所述振荡判断模块实时检测次/超同步振荡是否结束,若结束,则所述各直驱风机锁相环输入端的电压恢复为与所述锁相环相连的直驱风机的输出端电压。The oscillation recovery module is used to control the data acquisition module and the oscillation judgment module to detect in real time whether the sub-synchronous/super-synchronous oscillation has ended when the judgment result of the oscillation judgment module is that the oscillation has occurred. If it has ended, the voltage at the input end of the phase-locked loop of each direct-drive fan is restored to the output end voltage of the direct-drive fan connected to the phase-locked loop. 5.根据权利要求4所述的基于锁相一致的直驱风电场振荡抑制系统,其特征在于,在所述振荡判断模块中,所述判断直驱风电场是否发生次/超同步振荡,包括:5. The direct-drive wind farm oscillation suppression system based on phase-locked consistency according to claim 4 is characterized in that, in the oscillation judgment module, the judgment of whether sub-/super-synchronous oscillation occurs in the direct-drive wind farm includes: 若所述采集到的并网点处或任一直驱风机出口处的电流和/或电压的频率处于次/超同步振荡频率范围内,则判定直驱风电场发生次/超同步振荡。If the frequencies of the current and/or voltage collected at the grid connection point or at any outlet of the direct-driven wind turbine are within the sub-/super-synchronous oscillation frequency range, it is determined that sub-/super-synchronous oscillation occurs in the direct-driven wind farm. 6.根据权利要求5所述的基于锁相一致的直驱风电场振荡抑制系统,其特征在于,所述次同步振荡频率范围为2.5-50Hz;所述超同步振荡频率范围为50-97.5Hz。6. The direct-drive wind farm oscillation suppression system based on phase-locked consistency according to claim 5 is characterized in that the subsynchronous oscillation frequency range is 2.5-50 Hz; the supersynchronous oscillation frequency range is 50-97.5 Hz.
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