CN117955120B - Load transient voltage instability discrimination method and system based on power factor positive feedback - Google Patents

Load transient voltage instability discrimination method and system based on power factor positive feedback Download PDF

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CN117955120B
CN117955120B CN202410069649.2A CN202410069649A CN117955120B CN 117955120 B CN117955120 B CN 117955120B CN 202410069649 A CN202410069649 A CN 202410069649A CN 117955120 B CN117955120 B CN 117955120B
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voltage instability
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CN117955120A (en
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王晓辉
党崇阳
丁则文
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Shandong 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
    • H02J3/00Circuit arrangements for AC mains or AC distribution networks
    • H02J3/12Circuit arrangements for AC mains or AC distribution networks for adjusting voltage in AC networks by changing a characteristic of the network load
    • H02J3/16Circuit arrangements for AC mains or AC distribution networks for adjusting voltage in AC networks by changing a characteristic of the network load by adjustment of reactive power
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00Circuit arrangements for AC mains or AC distribution networks
    • H02J3/12Circuit arrangements for AC mains or AC distribution networks for adjusting voltage in AC networks by changing a characteristic of the network load
    • H02J3/14Circuit arrangements for AC mains or AC distribution networks for adjusting voltage in AC networks by changing a characteristic of the network load by switching loads on to, or off from, network, e.g. progressively balanced loading
    • H02J3/144Demand-response operation of the power transmission or distribution network
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00Circuit arrangements for AC mains or AC distribution networks
    • H02J3/38Arrangements for parallely feeding a single network by two or more generators, converters or transformers
    • H02J3/381Dispersed generators
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00Circuit arrangements for AC mains or AC distribution networks
    • H02J3/38Arrangements for parallely feeding a single network by two or more generators, converters or transformers
    • H02J3/46Controlling of the sharing of output between the generators, converters, or transformers
    • H02J3/466Scheduling the operation of the generators, e.g. connecting or disconnecting generators to meet a given demand
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2203/00Indexing scheme relating to details of circuit arrangements for AC mains or AC distribution networks
    • H02J2203/20Simulating, e g planning, reliability check, modelling or computer assisted design [CAD]
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2300/00Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
    • H02J2300/20The dispersed energy generation being of renewable origin
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2300/00Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
    • H02J2300/40Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation wherein a plurality of decentralised, dispersed or local energy generation technologies are operated simultaneously
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2310/00The network for supplying or distributing electric power characterised by its spatial reach or by the load
    • H02J2310/50The network for supplying or distributing electric power characterised by its spatial reach or by the load for selectively controlling the operation of the loads
    • H02J2310/56The network for supplying or distributing electric power characterised by its spatial reach or by the load for selectively controlling the operation of the loads characterised by the condition upon which the selective controlling is based
    • H02J2310/58The condition being electrical
    • H02J2310/60Limiting power consumption in the network or in one section of the network, e.g. load shedding or peak shaving

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Supply And Distribution Of Alternating Current (AREA)

Abstract

The invention provides a method and a system for judging the transient voltage instability of a load based on positive feedback of a power factor, which are used for deducing the transient voltage instability process of the load side based on a variable impedance model and determining the mechanism characteristic and the stability characteristic quantity of the transient voltage instability of the load side; carrying out measurable expression on the mechanism characteristic and the stable characteristic quantity by using bus power and a power factor angle cotangent value, and determining the response characteristic of transient voltage instability at a load side; and adding additional criteria to reduce the false judgment rate, constructing load transient voltage instability criteria based on positive feedback of the power factor, and judging whether the load transient voltage is unstable or not by using the criteria. The load transient voltage instability criterion based on the power factor positive feedback constructed by the invention directly starts from an instability mechanism, the selected response characteristic is easy to obtain in an actual power grid, and the misjudgment rate of a stable scene is lower on the premise of ensuring accurate identification of the load side voltage instability scene.

Description

基于功率因数正反馈的负荷暂态电压失稳判别方法与系统Method and system for judging load transient voltage instability based on power factor positive feedback

技术领域Technical Field

本发明属于电网稳定性判别技术领域,尤其涉及基于功率因数正反馈的负荷暂态电压失稳判别方法与系统。The present invention belongs to the technical field of power grid stability determination, and in particular relates to a load transient voltage instability determination method and system based on power factor positive feedback.

背景技术Background Art

本部分的陈述仅仅是提供了与本发明相关的背景技术信息,不必然构成在先技术。The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

电压稳定作为重要的传统稳定形态之一,长期倍受关注。其中,暂态电压失稳的有效判别一直是电压稳定研究的重要课题。近些年来,随着我国受端系统规模日益扩大,以及电力电子装备在电网中大量渗透,电力系统暂态电压稳定问题愈加凸显,传统预案式事件匹配的暂态电压稳定判别以及控制技术弊端逐步显现,基于响应特征判别暂态电压失稳势在必行。通常认为,常见的暂态电压失稳场景是由负荷因素主导的机电暂态过程。电力负荷中往往包含有根据所获取功率与预设目标的差异而调整自身阻抗的装备。正是此类动作机制在某些情况下造成了更多的负荷无功消耗和电网无功传输,从而有可能造成暂态电压失稳。As one of the important traditional stability forms, voltage stability has long received much attention. Among them, the effective identification of transient voltage instability has always been an important topic in voltage stability research. In recent years, with the increasing scale of my country's receiving systems and the large-scale penetration of power electronic equipment in the power grid, the problem of transient voltage stability in the power system has become more prominent. The shortcomings of the transient voltage stability identification and control technology of traditional plan-based event matching have gradually emerged. It is imperative to identify transient voltage instability based on response characteristics. It is generally believed that the common transient voltage instability scenario is an electromechanical transient process dominated by load factors. The power load often contains equipment that adjusts its own impedance according to the difference between the power obtained and the preset target. It is this kind of action mechanism that causes more load reactive power consumption and grid reactive power transmission in some cases, which may cause transient voltage instability.

在暂态电压失稳的判别方面,母线电压幅值可以反映电力系统电压水平,部分学者利用关键节点电压幅值变化率构造李雅普诺夫指数,依据该指数是否大于0判断系统暂态电压是否稳定。有部分国外学者通过特征参数的时间序列实现电压轨迹跟踪,该方法无需系统模型,在此基础上,国家电网相关研究人员分析机端电压幅值变化率——电压幅值偏差特性曲线构建暂态电压失稳判据。上述方法仅需要测量母线电压即可判断暂态电压是否失稳,但是仅仅利用母线电压幅值可能存在判别准确率不高以及判断时间过长的问题出现。针对新能源分布式并网与直流输电给负荷侧暂态电压稳定判别带来的挑战,相关研究人员进行分析。在传统直流发生严重故障或者从故障中恢复时,直流逆变器在控制系统的作用下从受端系统吸收大量无功功率,导致换流母线电压下降,引起附近变阻抗类负荷的不稳定域扩大,增加暂态电压失稳风险。基于此,部分学者通过分析在换流母线发生电压崩溃时逆变站各电气量的变化情况,建立直流受端系统稳定测度指标。如果新能源并网规模较大,但是系统无功补偿装置数量不足,那么会对系统暂态电压稳定造成影响。为了能够准确判断新能源参与下系统是否发生暂态电压失稳,部分学者定义电压严重度与故障极限切除时间等指标。In terms of judging transient voltage instability, the bus voltage amplitude can reflect the voltage level of the power system. Some scholars use the voltage amplitude change rate of key nodes to construct the Lyapunov index, and judge whether the system transient voltage is stable based on whether the index is greater than 0. Some foreign scholars realize voltage trajectory tracking through the time series of characteristic parameters. This method does not require a system model. On this basis, relevant researchers of the State Grid Corporation of China analyze the voltage amplitude change rate at the machine end-voltage amplitude deviation characteristic curve to construct a transient voltage instability judgment criterion. The above method only needs to measure the bus voltage to judge whether the transient voltage is unstable, but only using the bus voltage amplitude may have problems such as low judgment accuracy and long judgment time. Relevant researchers analyzed the challenges brought by new energy distributed grid connection and DC transmission to the load side transient voltage stability judgment. When a serious fault occurs in the traditional DC or it recovers from the fault, the DC inverter absorbs a large amount of reactive power from the receiving system under the action of the control system, resulting in a drop in the commutation bus voltage, causing the expansion of the instability domain of nearby variable impedance loads, and increasing the risk of transient voltage instability. Based on this, some scholars have established stability measurement indicators for the DC receiving end system by analyzing the changes in various electrical quantities in the inverter station when the voltage collapse occurs in the commutation bus. If the scale of new energy grid connection is large, but the number of reactive compensation devices in the system is insufficient, it will affect the transient voltage stability of the system. In order to accurately determine whether the system has transient voltage instability when new energy is involved, some scholars have defined indicators such as voltage severity and fault limit removal time.

上述研究虽然在一定程度上提出了暂态电压失稳的判别方法,但是这些判别方法均不是基于负荷侧暂态电压失稳的本质机理提出。Although the above studies have proposed methods for distinguishing transient voltage instability to a certain extent, these distinguishing methods are not based on the essential mechanism of transient voltage instability on the load side.

为了能够提高暂态电压失稳判据的准确性与时效性,部分学者结合实时测量信息,利用戴维南定理构造等效电路提出暂态电压失稳判据,但是在包含大量电力电子装备的电力系统中构造等效电路难度较大。另有相关研究人员发现负荷侧暂态电压失稳从机理上,可伴随线路有功功率持续减小与线路电流持续增大的正反馈过程,因此提出通过监测线路电流、线路有功功率与母线电压进行判稳,但是该判据对部分稳定案例的误判以及部分失稳案例的漏判原因并未阐明。In order to improve the accuracy and timeliness of transient voltage instability criterion, some scholars combined real-time measurement information and used Thevenin theorem to construct equivalent circuits to propose transient voltage instability criterion, but it is difficult to construct equivalent circuits in power systems containing a large number of power electronic equipment. Other related researchers found that transient voltage instability on the load side can be accompanied by a positive feedback process of continuous decrease in line active power and continuous increase in line current. Therefore, it is proposed to judge stability by monitoring line current, line active power and bus voltage, but the reasons for the misjudgment of some stable cases and the omission of some instability cases by this criterion are not explained.

发明内容Summary of the invention

为克服上述现有技术的不足,本发明提供了一种基于功率因数正反馈的负荷暂态电压失稳判别方法及系统,构建基于母线有功功率与母线功率因数角余切值正反馈的电压失稳判据,是从负荷侧暂态电压失稳最本质机理直接出发,从而保证该判据的实用性。In order to overcome the shortcomings of the above-mentioned prior art, the present invention provides a method and system for judging load transient voltage instability based on power factor positive feedback, and constructs a voltage instability judgment criterion based on positive feedback of bus active power and bus power factor angular cotangent value, which directly starts from the most essential mechanism of transient voltage instability on the load side, thereby ensuring the practicality of the judgment criterion.

为实现上述目的,本发明的第一个方面提供基于功率因数正反馈的负荷暂态电压失稳判别方法,包括:To achieve the above object, a first aspect of the present invention provides a method for determining load transient voltage instability based on power factor positive feedback, comprising:

基于变阻抗模型推演负荷侧暂态电压失稳过程,确定负荷侧暂态电压失稳的机理特征和稳定特征量;Based on the variable impedance model, the transient voltage instability process on the load side is deduced to determine the mechanism characteristics and stability characteristic quantities of the transient voltage instability on the load side;

利用母线功率以及功率因数角余切值对所述机理特征和稳定特征量实施可量测化表达,确定负荷侧暂态电压失稳的响应特征;The mechanism characteristics and stability characteristic quantities are expressed measurably by using bus power and cotangent value of power factor angle to determine the response characteristics of transient voltage instability on the load side;

增加附加判据减小误判率,将响应特征中的微分形式转换为差分形式,构建基于功率因数正反馈的负荷暂态电压失稳判据,利用所构建的负荷暂态电压失稳判据判断负荷侧暂态电压是否失稳。Additional criteria are added to reduce the false positive rate, the differential form in the response characteristics is converted into a differential form, a load transient voltage instability criterion based on power factor positive feedback is constructed, and the constructed load transient voltage instability criterion is used to determine whether the transient voltage on the load side is unstable.

进一步的,基于变阻抗模型推演负荷侧暂态电压失稳过程,确定负荷侧暂态电压失稳的机理特征,具体为:Furthermore, based on the variable impedance model, the transient voltage instability process on the load side is deduced, and the mechanism characteristics of the transient voltage instability on the load side are determined, specifically:

当变阻抗负荷进入不稳定域而发生失稳时,存在阻抗变化与负荷吸收有功功率获取之间的恶性正反馈特征;负荷吸收有功功率为获取有功功率预设目标而变阻抗,阻抗变化使得负荷吸收有功功率进一步偏离有功功率预设目标,从而形成负荷吸收有功功率偏离、负荷变阻抗、负荷吸收有功功率进一步偏离的正反馈过程。When the variable impedance load enters the unstable domain and becomes unstable, there is a vicious positive feedback characteristic between the impedance change and the load absorbing active power; the load absorbs active power and changes impedance to obtain the preset active power target. The impedance change causes the load absorbing active power to further deviate from the preset active power target, thus forming a positive feedback process in which the load absorbs active power deviation, the load changes impedance, and the load absorbs active power further deviates.

进一步的,基于变阻抗模型推演负荷侧暂态电压失稳过程,确定负荷侧暂态电压失稳的稳定特征量为负荷母线的等效阻抗,具体为:Furthermore, based on the variable impedance model, the transient voltage instability process on the load side is deduced, and the stable characteristic quantity of the transient voltage instability on the load side is determined to be the equivalent impedance of the load bus, specifically:

变阻抗负荷一阶微分模型如下式所示:The first-order differential model of variable impedance load is shown as follows:

式中,RLoad为等效负荷电阻;为电导的恢复时间常数;PL0为有功功率预设目标;PLoad为负荷吸收有功功率;Where, R Load is the equivalent load resistance; is the recovery time constant of conductivity; P L0 is the preset target of active power; P Load is the active power absorbed by the load;

确定负荷侧暂态电压失稳的稳定特征量为母线等效阻抗:The stable characteristic quantity of transient voltage instability on the load side is determined as the bus equivalent impedance:

式中,XLoad为等效负荷电抗。Where X Load is the equivalent load reactance.

进一步的,利用母线功率以及功率因数角余切值对所述机理特征和稳定特征量实施可量测化表达,确定负荷侧暂态电压失稳的响应特征,具体为:Furthermore, the bus power and the cotangent value of the power factor angle are used to implement a measurable expression of the mechanism characteristics and the stability characteristic quantity, and the response characteristics of the transient voltage instability on the load side are determined, specifically:

变阻抗负荷发生阻抗变化与母线功率偏离的恶性正反馈过程而失稳时,等效负荷阻抗持续降低,导致功率因数角余切值持续降低,从而吸收更多的无功功率导致电压崩溃;母线功率因数角余切值与等效负荷阻抗呈现一一对应关系,而母线功率因数角余切值更易于测量,因此用母线功率因数角余切值近似表征负荷阻抗的变化,形成可量测化的响应特征量。When the variable impedance load becomes unstable due to the vicious positive feedback process of impedance change and bus power deviation, the equivalent load impedance continues to decrease, resulting in a continuous decrease in the cotangent value of the power factor angle, thereby absorbing more reactive power and causing voltage collapse; the bus power factor angle cotangent value and the equivalent load impedance show a one-to-one correspondence, and the bus power factor angle cotangent value is easier to measure. Therefore, the bus power factor angle cotangent value is used to approximately characterize the change in load impedance, forming a measurable response characteristic.

进一步的,确定负荷侧暂态电压失稳的响应表征如下式所示:Furthermore, the response characterization of transient voltage instability on the load side is determined as follows:

式中,P为母线有功功率;Q为母线无功功率;为母线功率因数角余切值。In the formula, P is the bus active power; Q is the bus reactive power; is the cotangent value of the bus power factor.

进一步的,对于母线实际有功功率与预设目标有功功率曲线存在两个以上交点导致的误判场景,增加设置电压安全门槛值的方法减小误判率;对于电压动态上升过程中不稳定域收缩导致的误判场景,采用设置判据持续时间阈值的方法减小误判率。Furthermore, for the misjudgment scenario caused by the existence of more than two intersection points between the actual active power of the bus and the preset target active power curve, the method of setting the voltage safety threshold value is added to reduce the misjudgment rate; for the misjudgment scenario caused by the contraction of the unstable domain during the dynamic rise of voltage, the method of setting the judgment criterion duration threshold is used to reduce the misjudgment rate.

进一步的,增加附加判据减小误判率,将响应特征中的微分形式转换为差分形式,构建基于功率因数正反馈的负荷暂态电压失稳判据,具体为:Furthermore, additional criteria are added to reduce the misjudgment rate, the differential form in the response characteristics is converted into a differential form, and a load transient voltage instability criterion based on power factor positive feedback is constructed, specifically:

式中,Pk与Qk分别为第k时刻母线有功功率与无功功率;Pk+N与QktN分别为第k+N时刻母线有功功率与无功功率;t为母线有功功率下降与功率因数角余切值下降的持续时间;T1为判据持续时间阈值;为第k+N+T1时刻母线电压;U1为电压安全门槛值。Where, Pk and Qk are the bus active power and reactive power at the kth moment respectively; Pk +N and QktN are the bus active power and reactive power at the k+Nth moment respectively; t is the duration of the bus active power drop and the power factor cotangent value drop; T1 is the judgment duration threshold; is the bus voltage at the k+N+ T1 moment; U1 is the voltage safety threshold.

本发明的第二个方面提供基于功率因数正反馈的负荷暂态电压失稳判别系统,包括:A second aspect of the present invention provides a load transient voltage instability determination system based on power factor positive feedback, comprising:

第一确定模块:基于变阻抗模型推演负荷侧暂态电压失稳过程,确定负荷侧暂态电压失稳的机理特征和稳定特征量的模块;The first determination module: a module for deducing the transient voltage instability process on the load side based on the variable impedance model, and determining the mechanism characteristics and stability characteristic quantities of the transient voltage instability on the load side;

第二确定模块:利用母线功率以及功率因数角余切值对所述机理特征和稳定特征量实施可量测化表达,确定负荷侧暂态电压失稳的响应特征的模块;The second determination module: a module for implementing a measurable expression of the mechanism characteristics and stability characteristic quantities by using bus power and cotangent value of power factor angle to determine the response characteristics of transient voltage instability on the load side;

判别模块:增加附加判据减小误判率,将响应特征中的微分形式转换为差分形式,构建基于功率因数正反馈的负荷暂态电压失稳判据,利用所构建的负荷暂态电压失稳判据判断负荷侧暂态电压是否失稳的模块。Discrimination module: Add additional criteria to reduce the misjudgment rate, convert the differential form in the response characteristics into a differential form, construct a load transient voltage instability criterion based on power factor positive feedback, and use the constructed load transient voltage instability criterion to determine whether the transient voltage on the load side is unstable.

本发明的第三个方面提供一种计算机设备,包括:处理器、存储器和总线,所述存储器存储有所述处理器可执行的机器可读指令,当计算机设备运行时,所述处理器与所述存储器之间通过总线通信,所述机器可读指令被所述处理器执行时执行基于功率因数正反馈的负荷暂态电压失稳判别方法。The third aspect of the present invention provides a computer device, comprising: a processor, a memory and a bus, wherein the memory stores machine-readable instructions executable by the processor, and when the computer device is running, the processor and the memory communicate via the bus, and when the machine-readable instructions are executed by the processor, a load transient voltage instability judgment method based on power factor positive feedback is executed.

本发明的第四个方面提供一种计算机可读存储介质,所述计算机可读存储介质上存储有计算机程序,所述计算机程序被处理器运行时执行基于功率因数正反馈的负荷暂态电压失稳判别方法。A fourth aspect of the present invention provides a computer-readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, a method for determining load transient voltage instability based on positive feedback of power factor is executed.

以上一个或多个技术方案存在以下有益效果:One or more of the above technical solutions have the following beneficial effects:

本发明基于变阻抗模型确定负荷侧暂态电压失稳的稳定特征量,反映多个动态设备与静态设备共同作用造成的暂态电压失稳过程,避免了单一动态设备无法准确表征暂态电压失稳的问题。The present invention determines the stable characteristic quantity of transient voltage instability on the load side based on the variable impedance model, reflects the transient voltage instability process caused by the combined action of multiple dynamic devices and static devices, and avoids the problem that a single dynamic device cannot accurately characterize transient voltage instability.

本发明负荷侧暂态电压失稳的响应特征测量母线上的有功功率与无功功率,在实际电网中易于获取,计算速度快,能够更直观地表征负荷侧暂态电压失稳过程。The response characteristic of transient voltage instability on the load side of the present invention measures the active power and reactive power on the bus, which is easy to obtain in an actual power grid, has a fast calculation speed, and can more intuitively characterize the transient voltage instability process on the load side.

本发明构建的基于功率因数正反馈的负荷暂态电压失稳判据,从失稳机理直接出发,且将易产生误差的微分形式变换为差分形式,在保证负荷侧电压失稳场景准确识别的前提下,稳定场景的误判率较低。The load transient voltage instability criterion based on power factor positive feedback constructed by the present invention starts directly from the instability mechanism and transforms the differential form that is prone to errors into a differential form. Under the premise of ensuring accurate identification of the load side voltage instability scene, the misjudgment rate of the stable scene is low.

本发明附加方面的优点将在下面的描述中部分给出,部分将从下面的描述中变得明显,或通过本发明的实践了解到。Advantages of additional aspects of the present invention will be given in part in the following description, and in part will become obvious from the following description, or will be learned through practice of the present invention.

附图说明BRIEF DESCRIPTION OF THE DRAWINGS

构成本发明的一部分的说明书附图用来提供对本发明的进一步理解,本发明的示意性实施例及其说明用于解释本发明,并不构成对本发明的不当限定。The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

图1为本发明实施例一中负荷的变阻抗模型电路;FIG1 is a variable impedance model circuit of a load in Embodiment 1 of the present invention;

图2为本发明实施例一中等效负荷阻抗——负荷吸收有功功率,母线电压,流经负荷电流关系示意图;2 is a schematic diagram showing the relationship between equivalent load impedance, active power absorbed by the load, bus voltage, and current flowing through the load in the first embodiment of the present invention;

图3为本发明实施例一中运行点位于不同区域时运行点运行轨迹示意图;FIG3 is a schematic diagram of the running trajectory of the running point when the running point is located in different areas in the first embodiment of the present invention;

图4为本发明实施例一中实际有功功率与预设目标有功功率存在两个以上交点导致误判示意图;4 is a schematic diagram showing a misjudgment caused by the presence of more than two intersection points between the actual active power and the preset target active power in the first embodiment of the present invention;

图5为本发明实施例一中动态电压上升过程中不稳定域收缩导致误判示意图;FIG5 is a schematic diagram of misjudgment caused by the contraction of the unstable region during the dynamic voltage rise process in the first embodiment of the present invention;

图6为本发明实施例一中求解母线有功功率与无功功率示意图;FIG6 is a schematic diagram of solving bus active power and reactive power in Embodiment 1 of the present invention;

图7为本发明实施例一中1SB15222,2SB10222,3SB032221三个220kV稳定节点电压图像;FIG7 is a voltage image of three 220 kV stable nodes 1SB15222, 2SB10222, and 3SB032221 in Embodiment 1 of the present invention;

图8为本发明实施例一中1SB15222,2SB10222,3SB032221三个220kV稳定节点判定结果;FIG8 is a determination result of three 220 kV stable nodes 1SB15222, 2SB10222, and 3SB032221 in Embodiment 1 of the present invention;

图9为本发明实施例一中1RB07321 220kV失稳节点电压图像;FIG9 is a voltage image of a 220 kV unstable node of 1RB07321 in Example 1 of the present invention;

图10为本发明实施例一中1RB07321 220kV失稳节点判定结果;FIG10 is a result of determining the 1RB07321 220 kV instability node in the first embodiment of the present invention;

图11为本发明实施例一中负荷暂态电压失稳判别方法流程图。FIG. 11 is a flow chart of a method for determining load transient voltage instability in Embodiment 1 of the present invention.

具体实施方式DETAILED DESCRIPTION

应该指出,以下详细说明都是示例性的,旨在对本发明提供进一步的说明。除非另有指明,本文使用的所有技术和科学术语具有与本发明所属技术领域的普通技术人员通常理解的相同含义。It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

需要注意的是,这里所使用的术语仅是为了描述具体实施方式,而非意图限制根据本发明的示例性实施方式。It should be noted that the terms used herein are for describing specific embodiments only and are not intended to be limiting of exemplary embodiments according to the present invention.

在不冲突的情况下,本发明中的实施例及实施例中的特征可以相互组合。In the absence of conflict, the embodiments of the present invention and the features of the embodiments may be combined with each other.

实施例一Embodiment 1

如图11所示,本实施例公开了一种基于功率因数正反馈的负荷暂态电压失稳判别方法,包括:As shown in FIG11 , this embodiment discloses a method for determining load transient voltage instability based on power factor positive feedback, including:

基于变阻抗模型推演负荷侧暂态电压失稳过程,确定负荷侧暂态电压失稳的机理特征和稳定特征量;Based on the variable impedance model, the transient voltage instability process on the load side is deduced to determine the mechanism characteristics and stability characteristic quantities of the transient voltage instability on the load side;

利用母线功率以及功率因数角余切值对所述机理特征和稳定特征量实施可量测化表达,确定负荷侧暂态电压失稳的响应特征;The mechanism characteristics and stability characteristic quantities are expressed measurably by using bus power and cotangent value of power factor angle to determine the response characteristics of transient voltage instability on the load side;

增加附加判据减小误判率,构建基于功率因数正反馈的负荷暂态电压失稳判据,利用所构建的负荷暂态电压失稳判据判断负荷侧暂态电压是否失稳。Additional criteria are added to reduce the false positive rate, and a load transient voltage instability criterion based on power factor positive feedback is constructed. The constructed load transient voltage instability criterion is used to determine whether the transient voltage on the load side is unstable.

本实施例的方案旨在依据负荷侧暂态电压失稳最本质机理,提取负荷侧暂态电压失稳响应特征,利用基于功率因数正反馈的负荷暂态电压失稳判据实现对负荷侧暂态电压是否失稳进行判断。The solution of this embodiment aims to extract the response characteristics of transient voltage instability on the load side according to the most essential mechanism of transient voltage instability on the load side, and use the load transient voltage instability criterion based on power factor positive feedback to determine whether the transient voltage on the load side is unstable.

本实施例的方法的主要实施步骤如下:The main implementation steps of the method of this embodiment are as follows:

步骤1:确定负荷侧暂态电压失稳的机理特征和稳定特征量Step 1: Determine the mechanism characteristics and stability characteristics of transient voltage instability on the load side

构建交流电路如图1所示,RLine与XLine为线路电阻与电抗,RLoad与XLoad为等效负荷电阻与电抗,Er为单机无穷大电源电势。The AC circuit is constructed as shown in Figure 1, where R Line and X Line are the line resistance and reactance, R Load and X Load are the equivalent load resistance and reactance, and Er is the single-machine infinite power supply potential.

流经等效负荷电流如式(1)所示:The current flowing through the equivalent load is shown in formula (1):

等效负荷两端电压如式(2)所示:The voltage across the equivalent load is shown in formula (2):

负荷吸收有功功率如式(3)所示:The active power absorbed by the load is shown in formula (3):

负荷吸收无功功率如式(4)所示:The reactive power absorbed by the load is shown in formula (4):

假设在系统动态变化过程中,线路阻抗保持不变,联立公式(1)-(3),得到等效负荷阻抗——负荷吸收有功功率,母线电压,流经负荷电流关系示意图如图2所示。Assuming that the line impedance remains unchanged during the dynamic change of the system, formulas (1)-(3) are combined to obtain the equivalent load impedance-load absorbed active power, bus voltage, and load current relationship diagram as shown in Figure 2.

等效负荷电阻一阶模型如式(5)所示:The first-order model of equivalent load resistance is shown in formula (5):

式中,PL0为有功功率预设目标,为电导的恢复时间常数。Where P L0 is the preset target of active power, is the recovery time constant of the conductivity.

在电力系统受到大扰动后,若负荷位于O点与A点之间,PLoad<PL0,负荷通过减小自身的等效阻抗使得自身消耗有功功率升高,并最终在A点稳定;当负荷位于A点与C点之间,PLoad>PL0,负荷增大自身等效负荷阻抗,负荷吸收有功功率在C点与B点之间时升高,在B点与A点之间时降低,并最终A点稳定。当运行点位于C点以右时,PLoad<PL0,负荷等效负荷阻抗减小,但是负荷吸收有功功率反而进一步降低,形成正反馈过程。After the power system is greatly disturbed, if the load is between point O and point A, P Load <P L0 , the load increases its own active power consumption by reducing its own equivalent impedance, and finally stabilizes at point A; when the load is between point A and point C, P Load >P L0 , the load increases its own equivalent load impedance, the active power absorbed by the load increases between point C and point B, decreases between point B and point A, and finally stabilizes at point A. When the operating point is to the right of point C, P Load <P L0 , the load equivalent load impedance decreases, but the active power absorbed by the load further decreases, forming a positive feedback process.

综上所述,标注运行点位于O点与A点之间,A点与C点之间,C点以右的区域时运行点的运动轨迹如图3所示,发现系统负荷发生失稳伴随着等效负荷阻抗持续降低,但是负荷吸收有功功率持续下降的正反馈过程,该过程表达式如式(6)所示。因此,负荷吸收有功功率与等效负荷阻抗可以作为暂态稳定特征量。In summary, the movement trajectory of the operating point when the marked operating point is between point O and point A, between point A and point C, and in the area to the right of point C is shown in Figure 3. It is found that the instability of the system load is accompanied by a continuous decrease in the equivalent load impedance, but the positive feedback process of the load absorbing active power continues to decrease. The expression of this process is shown in formula (6). Therefore, the load absorbing active power and the equivalent load impedance can be used as transient stability characteristic quantities.

式中,PLoad为负荷吸收有功功率,ZLoad为等效负荷阻抗,作为负荷侧暂态电压失稳的稳定特征量。Where P Load is the active power absorbed by the load, and Z Load is the equivalent load impedance, which is used as the stable characteristic quantity of transient voltage instability on the load side.

步骤2:确定负荷侧暂态电压失稳的响应特征Step 2: Determine the response characteristics of transient voltage instability on the load side

在实际电网中,母线电压幅值与相角、母线有功功率、母线无功功率可以进行量测,但是等效负荷阻抗无法进行量测,因此,需要将等效负荷阻抗进行可量测化,才能在实际电网中得到有效应用。In actual power grids, bus voltage amplitude and phase angle, bus active power, and bus reactive power can be measured, but equivalent load impedance cannot be measured. Therefore, the equivalent load impedance needs to be measurable in order to be effectively applied in actual power grids.

根据图1所构建的交流电路模型,母线功率因数角余切值的表达式如式(7)所示:According to the AC circuit model constructed in Figure 1, the expression of the cotangent value of the bus power factor angle is shown in formula (7):

式中,R0为母线初始时刻等效负荷电阻,X0为母线初始时刻等效负荷电抗,vR为母线等效负荷电阻下降速率,vX为母线等效负荷电抗下降速率。Where R0 is the equivalent load resistance of the bus at the initial moment, X0 is the equivalent load reactance of the bus at the initial moment, vR is the decrease rate of the equivalent load resistance of the bus, and vX is the decrease rate of the equivalent load reactance of the bus.

假设vR与vX并不是有关时间的函数,令功率因数角余切值对时间进行求导,可得式(8)如下:Assuming that v R and v X are not functions of time, let the cotangent value of the power factor be differentiated with respect to time, and we can get equation (8) as follows:

如果等效负荷阻抗可以用母线功率因数角余切值近似表征,则需要满足关系式如式(9)所示:If the equivalent load impedance can be approximately represented by the cotangent value of the bus power factor angle, the relationship must be as shown in equation (9):

在式(9)条件下,母线功率因数角余切值随着等效负荷阻抗的减小而降低,该过程可能引起负荷吸收更多的无功功率导致母线电压崩溃。因此,暂态电压失稳可以描述为母线有功功率持续降低与母线功率因数角余切值持续降低的正反馈过程,从而确定负荷侧暂态电压失稳的响应表征如式(10)所示:Under the condition of formula (9), the cotangent value of the bus power factor decreases as the equivalent load impedance decreases. This process may cause the load to absorb more reactive power, resulting in bus voltage collapse. Therefore, transient voltage instability can be described as a positive feedback process of continuous reduction of bus active power and continuous reduction of bus power factor cotangent value, thereby determining the response characterization of transient voltage instability on the load side as shown in formula (10):

式中:P为母线有功功率,Q为母线无功功率,为母线功率因数角余切值。Where: P is the bus active power, Q is the bus reactive power, is the cotangent value of the bus power factor.

步骤3:构建基于功率因数正反馈的负荷暂态电压失稳判据Step 3: Construct a load transient voltage instability criterion based on power factor positive feedback

式(10)存在的误判场景有两种:(1)母线实际有功功率曲线与预设目标有功功率曲线存在两个以上的交点;(2)动态过程中电压上升导致不稳定域收缩。There are two misjudgment scenarios in equation (10): (1) there are more than two intersection points between the actual active power curve of the bus and the preset target active power curve; (2) the voltage rise in the dynamic process causes the unstable region to shrink.

当母线实际有功功率与预设目标有功功率曲线存在三个交点时,画出运行点在O点至A点,A点至B点,B点至C点以及C点以后的运行轨迹如图4所示,通过对运行点运行轨迹的分析,运行点在各个区域最后均能够保持稳定。但是,当运行点位于B点至C点时,会出现等效负荷阻抗减小与有功功率减小的过程,这会导致误判的发生。When there are three intersections between the actual active power of the bus and the preset target active power curve, the operation trajectory of the operating point from point O to point A, point A to point B, point B to point C, and after point C is drawn as shown in Figure 4. Through the analysis of the operation trajectory of the operating point, the operating point can finally remain stable in each area. However, when the operating point is between point B and point C, there will be a process of reducing the equivalent load impedance and reducing the active power, which will lead to misjudgment.

针对母线实际有功功率与预设目标有功功率曲线存在两个以上交点导致的误判场景,可以采取设置电压安全门槛值的方法减小误判率。该方法将电压安全问题与电压稳定问题一同考虑,当电压为安全电压时,判据不会触发,从而规避误判。For scenarios where there are more than two intersections between the actual active power of the busbar and the preset target active power curve, the method of setting a voltage safety threshold can be used to reduce the misjudgment rate. This method considers voltage safety issues and voltage stability issues together. When the voltage is a safe voltage, the judgment criteria will not be triggered, thereby avoiding misjudgment.

电压动态上升过程中不稳定域收缩示意图如图5所示,运行点刚开始位于A点,此时为不稳定域,运行点从A点向B点移动;运行点位于B点时,电压上升,此时运行点从B点向C点移动,由不稳定域运行到稳定域中;运行点位于C点以后,若电压不变,则运行点会一直在稳定域中,并最终运行到稳定点。但是,当运行点在不稳定域的时候,基于功率因数正反馈的负荷暂态电压失稳判据已经触发,导致误判发生。The schematic diagram of the contraction of the unstable domain during the dynamic voltage rise is shown in Figure 5. The operating point is initially located at point A, which is the unstable domain, and the operating point moves from point A to point B; when the operating point is at point B, the voltage rises, and the operating point moves from point B to point C, running from the unstable domain to the stable domain; after the operating point is at point C, if the voltage remains unchanged, the operating point will remain in the stable domain and eventually run to the stable point. However, when the operating point is in the unstable domain, the load transient voltage instability criterion based on power factor positive feedback has been triggered, resulting in a misjudgment.

针对电压动态上升过程中不稳定域收缩导致的误判场景,可以采用设置判据持续时间阈值的方法减小误判率。该方法通过在判据中增加判据持续时间阈值,从而减少运行点由不稳定域返回稳定域导致的误判概率。For the misjudgment scenario caused by the contraction of the unstable region during the dynamic voltage rise, the method of setting the judgment duration threshold can be used to reduce the misjudgment rate. This method reduces the probability of misjudgment caused by the return of the operating point from the unstable region to the stable region by adding the judgment duration threshold in the judgment.

因此,在原先基于功率因数正反馈的负荷暂态电压失稳判据的基础上,增加电压安全门槛值与判据持续时间阈值两个附加判据减小误判率,增加附加判据后的基于功率因数正反馈的负荷暂态电压失稳判据如式(11)所示:Therefore, on the basis of the original load transient voltage instability criterion based on power factor positive feedback, two additional criteria, namely voltage safety threshold value and criterion duration threshold value, are added to reduce the misjudgment rate. The load transient voltage instability criterion based on power factor positive feedback after adding the additional criteria is shown in formula (11):

式中,U为母线电压;U1为设置的电压安全门槛值;t为母线有功功率下降与功率因数角余切值下降(即公式(11)前两行)的持续时间;T1为判据持续时间阈值。Where U is the bus voltage; U1 is the set voltage safety threshold; t is the duration of the bus active power drop and the power factor cotangent value drop (i.e., the first two lines of formula (11)); T1 is the judgment duration threshold.

为了减小实际电网中可能存在的功角动态与量测噪声产生的误差,采用时间滑窗差分替代微分的方法,最终所构建的基于功率因数正反馈的负荷暂态电压失稳判据如式(12)所示:In order to reduce the errors caused by the power angle dynamics and measurement noise that may exist in the actual power grid, the time sliding window difference is used to replace the differential method. The final load transient voltage instability criterion based on power factor positive feedback is shown in formula (12):

式中,Pk与Qk为第k时刻母线有功功率与无功功率;Pk+N与Qk+N为第k+N时刻母线有功功率与无功功率;为第k+N+T1时刻母线电压。Where, Pk and Qk are the bus active power and reactive power at the kth moment; Pk +N and Qk +N are the bus active power and reactive power at the k+Nth moment; is the bus voltage at the k+N+ T1 moment.

算例分析:电科院万节点测试系统主要包括送端测试系统和受端测试系统两个子系统。包含10575个三相节点:约550台同步电源;风/光可再生能源场站1031个;电源总装机28958万千瓦,常规机组装机17896万千瓦,新能源装机11062万千瓦(占总装机38.2%);6回直流,其中送受端通过3回800万直流相连,送端1回送往其他电网,受端2回由其他电网馈入。Case analysis: The 10,000-node test system of the Electric Power Research Institute mainly includes two subsystems: the sending end test system and the receiving end test system. It includes 10,575 three-phase nodes: about 550 synchronous power supplies; 1,031 wind/solar renewable energy stations; total installed power capacity of 289.58 million kilowatts, 178.96 million kilowatts of conventional power installed capacity, and 110.62 million kilowatts of new energy installed capacity (accounting for 38.2% of the total installed capacity); 6 DC loops, of which the sending and receiving ends are connected through 3 8 million DC loops, 1 loop at the sending end is sent to other power grids, and 2 loops at the receiving end are fed from other power grids.

送端测试系统以500千伏为主网架,分3个区:分区1S高比例新能源风火打捆外送;分区2S常规负荷中心;分区3S高比例水电外送,存在与主网弱联系断面。包含4941个三相节点;同步电源295台;风/光可再生能源场站392个;电源总装机15498万千瓦,常规机组装机8728万千瓦,新能源装机6770万千瓦(风电5505万千瓦、光伏1265万千瓦,占总装机43.68%;4回直流(400万千瓦*1+800万千瓦*3)。The sending-end test system is based on a 500 kV main grid and is divided into three zones: Zone 1S with a high proportion of new energy wind and fire bundled transmission; Zone 2S with conventional load centers; Zone 3S with a high proportion of hydropower transmission, with a weak connection section with the main grid. It includes 4,941 three-phase nodes; 295 synchronous power sources; 392 wind/solar renewable energy stations; total installed power capacity of 154.98 million kilowatts, 87.28 million kilowatts of conventional units, and 67.7 million kilowatts of new energy (55.05 million kilowatts of wind power and 12.65 million kilowatts of photovoltaic power, accounting for 43.68% of the total installed capacity; 4 DC (4 million kilowatts*1+8 million kilowatts*3).

受端测试系统以500千伏为主网架,分4个区:分区1R受电区域;分区2R含高比例新能源;分区3R交直流混联受电;分区4R是纯电源基地,与主网弱联系。包含5624个三相节点,8767支路;同步电源255台;风/光可再生能源场站639个;电源总装机13570万千瓦,常规机组装机9278万千瓦,新能源装机4292万千瓦(风电装机1300万千瓦,光伏装机2992万千瓦:A类和B类光伏各50%);馈入直流5条,包含4回+800千伏特高压直流、额定功率800万千瓦,1回+660千伏直流、额定功率400万千瓦。The receiving end test system is based on a 500 kV main grid and is divided into four areas: Zone 1R is the receiving area; Zone 2R contains a high proportion of new energy; Zone 3R is a hybrid AC/DC receiving area; Zone 4R is a pure power supply base with a weak connection to the main grid. It includes 5,624 three-phase nodes, 8,767 branches; 255 synchronous power sources; 639 wind/solar renewable energy stations; total installed power capacity of 135.7 million kilowatts, conventional installed capacity of 92.78 million kilowatts, and new energy installed capacity of 42.92 million kilowatts (wind power installed capacity of 13 million kilowatts, photovoltaic installed capacity of 29.92 million kilowatts: 50% each for Class A and Class B photovoltaic); 5 DC feed-in lines, including 4 +800 kV UHV DC with a rated power of 8 million kilowatts, and 1 +660 kV DC with a rated power of 4 million kilowatts.

在高峰103运行方式下,负荷7795.4千瓦。5条直流共馈入2800万千瓦,直流馈入占负荷的35%。常规机组发电3930万千瓦,新能源发电1065.36万千瓦(风电开机93.36万千瓦,光伏开机972万千瓦),新能源出力占发电20%、占负荷13.6%。分区1R为负荷中心,大比例交流受电。负荷1736万千瓦,发电855万千瓦(常规机组567万,分布式新能源288万:占负荷17%);交流受电881万千瓦,受电占比50%。Under the peak 103 operation mode, the load is 7795.4 kilowatts. 5 DC lines feed in a total of 28 million kilowatts, and DC feed-in accounts for 35% of the load. Conventional units generate 39.3 million kilowatts of electricity, and new energy generates 10.6536 million kilowatts of electricity (933,600 kilowatts of wind power and 9.72 million kilowatts of photovoltaic power). New energy output accounts for 20% of power generation and 13.6% of load. Partition 1R is the load center, with a large proportion of AC power. The load is 17.36 million kilowatts, and the power generation is 8.55 million kilowatts (5.67 million conventional units and 2.88 million distributed new energy: accounting for 17% of the load); AC power is 8.81 million kilowatts, accounting for 50% of the power.

对受端带负荷的母线电压及其相关线路有功功率与线路无功功率进行监测,对相关线路有功功率与无功功率分别进行求和得到母线有功功率与无功功率。在母线上应用基于功率因数正反馈的负荷暂态电压失稳判据,若有一个母线判据成立,则该系统被判定为暂态电压失稳。The bus voltage with load at the receiving end and its related line active power and line reactive power are monitored, and the active power and reactive power of the related lines are summed up to obtain the bus active power and reactive power. The load transient voltage instability criterion based on power factor positive feedback is applied to the bus. If one of the bus criterion is established, the system is judged as transient voltage instability.

以图6为例,若要判断220kV B节点是否暂态电压稳定,需要根据式(13)与式(14)分别求得220kV B节点的母线有功功率与母线无功功率,在该节点上应用基于功率因数正反馈的负荷暂态电压失稳判据判断该节点是否发生暂态电压失稳。Taking Figure 6 as an example, if we want to determine whether the transient voltage of the 220kV B node is stable, we need to obtain the bus active power and bus reactive power of the 220kV B node according to equations (13) and (14) respectively, and apply the load transient voltage instability criterion based on power factor positive feedback at this node to determine whether transient voltage instability occurs at this node.

P=P1+P21+P22+P3 (13)P=P 1 +P 21 +P 22 +P 3 (13)

Q=Q1+Q21+Q22+Q3 (14)Q=Q 1 +Q 21 +Q 22 +Q 3 (14)

1SB15222,2SB10222,3SB032221等220kV节点电压图像如图7所示,这些节点在10s内电压均恢复到0.8pu以上,因此它们属于稳定节点。对这三个节点用基于功率因数正反馈的负荷暂态电压失稳判据进行判定,结果均如图8所示,输出“0”代表没有触发判据,输出“1”代表触发判据,这三个节点均没有触发判据,因此这三个节点能够正确被判为稳定。The voltage images of 220kV nodes such as 1SB15222, 2SB10222, and 3SB032221 are shown in Figure 7. The voltages of these nodes all recovered to above 0.8pu within 10s, so they are stable nodes. The three nodes were judged by the load transient voltage instability criterion based on power factor positive feedback, and the results are shown in Figure 8. The output "0" represents no trigger criterion, and the output "1" represents a trigger criterion. None of these three nodes triggered the criterion, so these three nodes can be correctly judged as stable.

电压等级为220kV的1RB07321节点电压图像如图9所示,该节点在10s内电压没有恢复到0.8pu以上,因此该节点属于失稳节点。对该节点用基于功率因数正反馈的负荷暂态电压失稳判据进行判定,结果如图10所示,判定结果出现输出“1”的情况,因此该节点能够正确被判为失稳。The voltage image of the 1RB07321 node with a voltage level of 220kV is shown in Figure 9. The voltage of this node did not recover to above 0.8pu within 10s, so this node is an unstable node. The node was judged using the load transient voltage instability criterion based on power factor positive feedback. The result is shown in Figure 10. The judgment result outputs "1", so the node can be correctly judged as unstable.

通过上述分析,基于功率因数正反馈的负荷暂态电压失稳判据能够正确判别节点是否稳定。Through the above analysis, the load transient voltage instability criterion based on power factor positive feedback can correctly determine whether the node is stable.

实施例二Embodiment 2

本实施例的目的是提供基于功率因数正反馈的负荷暂态电压失稳判别系统,包括:The purpose of this embodiment is to provide a load transient voltage instability judgment system based on power factor positive feedback, including:

第一确定模块:基于变阻抗模型推演负荷侧暂态电压失稳过程,确定负荷侧暂态电压失稳的机理特征和稳定特征量的模块;The first determination module: a module for deducing the transient voltage instability process on the load side based on the variable impedance model, and determining the mechanism characteristics and stability characteristic quantities of the transient voltage instability on the load side;

第二确定模块:利用母线功率以及功率因数角余切值对所述机理特征和稳定特征量实施可量测化表达,确定负荷侧暂态电压失稳的响应特征的模块;The second determination module: a module for implementing a measurable expression of the mechanism characteristics and stability characteristic quantities by using bus power and cotangent value of power factor angle to determine the response characteristics of transient voltage instability on the load side;

判别模块:增加附加判据减小误判率,将响应特征中的微分形式转换为差分形式,构建基于功率因数正反馈的负荷暂态电压失稳判据,利用所构建的负荷暂态电压失稳判据判断负荷侧暂态电压是否失稳的模块。Discrimination module: Add additional criteria to reduce the misjudgment rate, convert the differential form in the response characteristics into a differential form, construct a load transient voltage instability criterion based on power factor positive feedback, and use the constructed load transient voltage instability criterion to determine whether the transient voltage on the load side is unstable.

实施例三Embodiment 3

本实施例的目的是提供一种计算装置,包括:处理器、存储器和总线,所述存储器存储有所述处理器可执行的机器可读指令,当计算机设备运行时,所述处理器与所述存储器之间通过总线通信,所述机器可读指令被所述处理器执行时上述方法的步骤。The purpose of this embodiment is to provide a computing device, including: a processor, a memory and a bus, wherein the memory stores machine-readable instructions executable by the processor, and when the computer device is running, the processor and the memory communicate through the bus, and the steps of the above method are performed when the machine-readable instructions are executed by the processor.

实施例四Embodiment 4

本实施例的目的是提供一种计算机可读存储介质。The purpose of this embodiment is to provide a computer-readable storage medium.

一种计算机可读存储介质,其上存储有计算机程序,该程序被处理器执行时执行上述方法的步骤。A computer-readable storage medium stores a computer program, which executes the steps of the above method when executed by a processor.

以上实施例二、三和四的装置中涉及的各步骤与方法实施例一相对应,具体实施方式可参见实施例一的相关说明部分。术语“计算机可读存储介质”应该理解为包括一个或多个指令集的单个介质或多个介质;还应当被理解为包括任何介质,所述任何介质能够存储、编码或承载用于由处理器执行的指令集并使处理器执行本发明中的任一方法。The steps involved in the apparatuses of the above embodiments 2, 3 and 4 correspond to the method embodiment 1, and the specific implementation methods can refer to the relevant description part of embodiment 1. The term "computer-readable storage medium" should be understood as a single medium or multiple media including one or more instruction sets; it should also be understood to include any medium that can store, encode or carry an instruction set for execution by a processor and enable the processor to execute any method in the present invention.

本领域技术人员应该明白,上述本发明的各模块或各步骤可以用通用的计算机装置来实现,可选地,它们可以用计算装置可执行的程序代码来实现,从而,可以将它们存储在存储装置中由计算装置来执行,或者将它们分别制作成各个集成电路模块,或者将它们中的多个模块或步骤制作成单个集成电路模块来实现。本发明不限制于任何特定的硬件和软件的结合。Those skilled in the art should understand that the modules or steps of the present invention described above can be implemented by a general-purpose computer device, or alternatively, they can be implemented by a program code executable by a computing device, so that they can be stored in a storage device and executed by the computing device, or they can be made into individual integrated circuit modules, or multiple modules or steps therein can be made into a single integrated circuit module for implementation. The present invention is not limited to any specific combination of hardware and software.

上述虽然结合附图对本发明的具体实施方式进行了描述,但并非对本发明保护范围的限制,所属领域技术人员应该明白,在本发明的技术方案的基础上,本领域技术人员不需要付出创造性劳动即可做出的各种修改或变形仍在本发明的保护范围以内。Although the above describes the specific implementation mode of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Technical personnel in the relevant field should understand that various modifications or variations that can be made by technical personnel in the field without creative work on the basis of the technical solution of the present invention are still within the scope of protection of the present invention.

Claims (4)

1.基于功率因数正反馈的负荷暂态电压失稳判别方法,其特征在于,包括:1. A method for determining load transient voltage instability based on power factor positive feedback, characterized by comprising: 基于变阻抗模型推演负荷侧暂态电压失稳过程,确定负荷侧暂态电压失稳的机理特征和稳定特征量;Based on the variable impedance model, the transient voltage instability process on the load side is deduced to determine the mechanism characteristics and stability characteristic quantities of the transient voltage instability on the load side; 所述基于变阻抗模型推演负荷侧暂态电压失稳过程,确定负荷侧暂态电压失稳的机理特征,具体为:The load-side transient voltage instability process is deduced based on the variable impedance model to determine the mechanism characteristics of the load-side transient voltage instability, specifically: 当变阻抗负荷进入不稳定域而发生失稳时,存在阻抗变化与负荷吸收有功功率获取之间的恶性正反馈特征;负荷吸收有功功率为获取有功功率预设目标而变阻抗,阻抗变化使得负荷吸收有功功率进一步偏离有功功率预设目标,从而形成负荷吸收有功功率偏离、负荷变阻抗、负荷吸收有功功率进一步偏离的正反馈过程;When the variable impedance load enters the unstable region and becomes unstable, there is a vicious positive feedback feature between the impedance change and the load absorbing active power acquisition; the load absorbs active power and changes impedance to obtain the preset active power target, and the impedance change causes the load to absorb active power further deviate from the preset active power target, thus forming a positive feedback process in which the load absorbs active power deviation, the load changes impedance, and the load absorbs active power further deviates; 所述基于变阻抗模型推演负荷侧暂态电压失稳过程,确定负荷侧暂态电压失稳的稳定特征量为负荷母线的等效阻抗,具体为:The transient voltage instability process on the load side is deduced based on the variable impedance model, and the stable characteristic quantity of the transient voltage instability on the load side is determined to be the equivalent impedance of the load bus, which is specifically: 变阻抗负荷一阶微分模型为:The first-order differential model of variable impedance load is: 式中,RLoad为等效负荷电阻;为电导的恢复时间常数;PL0为有功功率预设目标;PLoad为负荷吸收有功功率;Where, R Load is the equivalent load resistance; is the recovery time constant of conductivity; P L0 is the preset target of active power; P Load is the active power absorbed by the load; 确定负荷侧暂态电压失稳的稳定特征量为母线等效阻抗:The stable characteristic quantity of transient voltage instability on the load side is determined as the bus equivalent impedance: 式中,XLoad为等效负荷电抗;Where, X Load is the equivalent load reactance; 利用母线功率以及功率因数角余切值对所述机理特征和稳定特征量实施可量测化表达,确定负荷侧暂态电压失稳的响应特征;The mechanism characteristics and stability characteristic quantities are expressed measurably by using bus power and cotangent value of power factor angle to determine the response characteristics of transient voltage instability on the load side; 所述利用母线功率以及功率因数角余切值对所述机理特征和稳定特征量实施可量测化表达,确定负荷侧暂态电压失稳的响应特征,具体为:The bus power and the cotangent value of the power factor are used to implement a measurable expression of the mechanism characteristics and the stability characteristic quantity to determine the response characteristics of the transient voltage instability on the load side, specifically: 变阻抗负荷发生阻抗变化与母线功率偏离的恶性正反馈过程而失稳时,等效负荷阻抗持续降低,导致母线功率因数角余切值持续降低,从而吸收更多的无功功率导致电压崩溃;母线功率因数角余切值与等效负荷阻抗呈现一一对应关系,而母线功率因数角余切值更易于测量;因此用母线功率因数角余切值近似表征等效负荷阻抗的变化,形成可量测化的响应特征量;When the variable impedance load loses stability due to the vicious positive feedback process of impedance change and bus power deviation, the equivalent load impedance continues to decrease, resulting in a continuous decrease in the bus power factor angular cotangent value, thereby absorbing more reactive power and causing voltage collapse; the bus power factor angular cotangent value and the equivalent load impedance show a one-to-one correspondence, and the bus power factor angular cotangent value is easier to measure; therefore, the bus power factor angular cotangent value is used to approximately characterize the change in the equivalent load impedance, forming a measurable response characteristic; 确定负荷侧暂态电压失稳的响应表征为:The response characterization of transient voltage instability on the load side is determined as: 式中,P为母线有功功率;Q为母线无功功率;为母线功率因数角余切值;In the formula, P is the bus active power; Q is the bus reactive power; is the cotangent value of bus power factor; 增加附加判据减小误判率,将响应特征中的微分形式转换为差分形式,构建基于功率因数正反馈的负荷暂态电压失稳判据,利用所构建的负荷暂态电压失稳判据判断负荷侧暂态电压是否失稳,具体为:Add additional criteria to reduce the false positive rate, convert the differential form in the response characteristics into differential form, construct a load transient voltage instability criterion based on power factor positive feedback, and use the constructed load transient voltage instability criterion to determine whether the transient voltage on the load side is unstable. Specifically: 式中,Pk与Qk分别为第k时刻母线有功功率与无功功率;Pk+N与Qk+N分别为第k+N时刻母线有功功率与无功功率;t为母线有功功率下降与功率因数角余切值下降的持续时间;T1为判据持续时间阈值;为第k+N+T1时刻母线电压;U1为电压安全门槛值;Where, Pk and Qk are the bus active power and reactive power at the kth moment respectively; Pk +N and Qk +N are the bus active power and reactive power at the k+Nth moment respectively; t is the duration of the bus active power drop and the power factor cotangent value drop; T1 is the judgment duration threshold; is the bus voltage at the k+N+ T1 moment; U1 is the voltage safety threshold; 对于母线实际有功功率与预设目标有功功率曲线存在两个以上交点导致的误判场景,增加设置电压安全门槛值的方法减小误判率;对于电压动态上升过程中不稳定域收缩导致的误判场景,采用设置判据持续时间阈值的方法减小误判率;For misjudgment scenarios caused by more than two intersections between the actual bus active power and the preset target active power curve, the method of setting a voltage safety threshold value is used to reduce the misjudgment rate; for misjudgment scenarios caused by the contraction of the unstable domain during the dynamic rise of voltage, the method of setting the judgment criterion duration threshold is used to reduce the misjudgment rate; 所述附加判据为电压安全门槛值与判据持续时间阈值。The additional criteria are a voltage safety threshold value and a criterion duration threshold value. 2.基于功率因数正反馈的负荷暂态电压失稳判别系统,其特征在于,包括:2. A load transient voltage instability judgment system based on power factor positive feedback, characterized in that it includes: 第一确定模块:基于变阻抗模型推演负荷侧暂态电压失稳过程,确定负荷侧暂态电压失稳的机理特征和稳定特征量的模块;The first determination module: a module for deducing the transient voltage instability process on the load side based on the variable impedance model, and determining the mechanism characteristics and stability characteristic quantities of the transient voltage instability on the load side; 所述基于变阻抗模型推演负荷侧暂态电压失稳过程,确定负荷侧暂态电压失稳的机理特征,具体为:The load-side transient voltage instability process is deduced based on the variable impedance model to determine the mechanism characteristics of the load-side transient voltage instability, specifically: 当变阻抗负荷进入不稳定域而发生失稳时,存在阻抗变化与负荷吸收有功功率获取之间的恶性正反馈特征;负荷吸收有功功率为获取有功功率预设目标而变阻抗,阻抗变化使得负荷吸收有功功率进一步偏离有功功率预设目标,从而形成负荷吸收有功功率偏离、负荷变阻抗、负荷吸收有功功率进一步偏离的正反馈过程;When the variable impedance load enters the unstable region and becomes unstable, there is a vicious positive feedback feature between the impedance change and the load absorbing active power acquisition; the load absorbs active power and changes impedance to obtain the preset active power target, and the impedance change causes the load to absorb active power further deviate from the preset active power target, thus forming a positive feedback process in which the load absorbs active power deviation, the load changes impedance, and the load absorbs active power further deviates; 所述基于变阻抗模型推演负荷侧暂态电压失稳过程,确定负荷侧暂态电压失稳的稳定特征量为负荷母线的等效阻抗,具体为:The transient voltage instability process on the load side is deduced based on the variable impedance model, and the stable characteristic quantity of the transient voltage instability on the load side is determined to be the equivalent impedance of the load bus, which is specifically: 变阻抗负荷一阶微分模型为:The first-order differential model of variable impedance load is: 式中,RLoad为等效负荷电阻;为电导的恢复时间常数;PL0为有功功率预设目标;PLoad为负荷吸收有功功率;Where, R Load is the equivalent load resistance; is the recovery time constant of conductivity; P L0 is the preset target of active power; P Load is the active power absorbed by the load; 确定负荷侧暂态电压失稳的稳定特征量为母线等效阻抗:The stable characteristic quantity of transient voltage instability on the load side is determined as the bus equivalent impedance: 式中,XLoad为等效负荷电抗;Where, X Load is the equivalent load reactance; 第二确定模块:利用母线功率以及功率因数角余切值对所述机理特征和稳定特征量实施可量测化表达,确定负荷侧暂态电压失稳的响应特征的模块;The second determination module: a module for implementing a measurable expression of the mechanism characteristics and stability characteristic quantities by using bus power and cotangent value of power factor angle to determine the response characteristics of transient voltage instability on the load side; 所述利用母线功率以及功率因数角余切值对所述机理特征和稳定特征量实施可量测化表达,确定负荷侧暂态电压失稳的响应特征,具体为:The bus power and the cotangent value of the power factor are used to implement a measurable expression of the mechanism characteristics and the stability characteristic quantity to determine the response characteristics of the transient voltage instability on the load side, specifically: 变阻抗负荷发生阻抗变化与母线功率偏离的恶性正反馈过程而失稳时,等效负荷阻抗持续降低,导致母线功率因数角余切值持续降低,从而吸收更多的无功功率导致电压崩溃;母线功率因数角余切值与等效负荷阻抗呈现一一对应关系,而母线功率因数角余切值更易于测量;因此用母线功率因数角余切值近似表征等效负荷阻抗的变化,形成可量测化的响应特征量;When the variable impedance load loses stability due to the vicious positive feedback process of impedance change and bus power deviation, the equivalent load impedance continues to decrease, resulting in a continuous decrease in the bus power factor angular cotangent value, thereby absorbing more reactive power and causing voltage collapse; the bus power factor angular cotangent value and the equivalent load impedance show a one-to-one correspondence, and the bus power factor angular cotangent value is easier to measure; therefore, the bus power factor angular cotangent value is used to approximately characterize the change in the equivalent load impedance, forming a measurable response characteristic; 确定负荷侧暂态电压失稳的响应表征为:The response characterization of transient voltage instability on the load side is determined as: 式中,P为母线有功功率;Q为母线无功功率;为母线功率因数角余切值;In the formula, P is the bus active power; Q is the bus reactive power; is the cotangent value of bus power factor; 判别模块:增加附加判据减小误判率,将响应特征中的微分形式转换为差分形式,构建基于功率因数正反馈的负荷暂态电压失稳判据,利用所构建的负荷暂态电压失稳判据判断负荷侧暂态电压是否失稳的模块,具体为:Discrimination module: Add additional criteria to reduce the misjudgment rate, convert the differential form in the response characteristics into differential form, construct a load transient voltage instability criterion based on power factor positive feedback, and use the constructed load transient voltage instability criterion to determine whether the transient voltage on the load side is unstable. Specifically: 式中,Pk与Qk分别为第k时刻母线有功功率与无功功率;Pk+N与Qk+N分别为第k+N时刻母线有功功率与无功功率;t为母线有功功率下降与功率因数角余切值下降的持续时间;T1为判据持续时间阈值;为第k+N+T1时刻母线电压;U1为电压安全门槛值;Where, Pk and Qk are the bus active power and reactive power at the kth moment, respectively; Pk +N and Qk +N are the bus active power and reactive power at the k+Nth moment, respectively; t is the duration of the bus active power drop and the power factor cotangent value drop; T1 is the judgment duration threshold; is the bus voltage at the k+N+ T1 moment; U1 is the voltage safety threshold; 对于母线实际有功功率与预设目标有功功率曲线存在两个以上交点导致的误判场景,增加设置电压安全门槛值的方法减小误判率;对于电压动态上升过程中不稳定域收缩导致的误判场景,采用设置判据持续时间阈值的方法减小误判率;For misjudgment scenarios caused by more than two intersections between the actual bus active power and the preset target active power curve, the method of setting a voltage safety threshold value is used to reduce the misjudgment rate; for misjudgment scenarios caused by the contraction of the unstable domain during the dynamic rise of voltage, the method of setting the judgment criterion duration threshold is used to reduce the misjudgment rate; 所述附加判据为电压安全门槛值与判据持续时间阈值。The additional criteria are a voltage safety threshold value and a criterion duration threshold value. 3.一种计算机设备,其特征在于,包括:处理器、存储器和总线,所述存储器存储有所述处理器可执行的机器可读指令,当计算机设备运行时,所述处理器与所述存储器之间通过总线通信,所述机器可读指令被所述处理器执行时执行如权利要求1所述的基于功率因数正反馈的负荷暂态电压失稳判别方法。3. A computer device, characterized in that it includes: a processor, a memory and a bus, the memory stores machine-readable instructions executable by the processor, when the computer device is running, the processor and the memory communicate through the bus, and when the machine-readable instructions are executed by the processor, the load transient voltage instability judgment method based on power factor positive feedback as described in claim 1 is executed. 4.一种计算机可读存储介质,其特征在于,所述计算机可读存储介质上存储有计算机程序,所述计算机程序被处理器运行时执行如权利要求1所述的基于功率因数正反馈的负荷暂态电压失稳判别方法。4. A computer-readable storage medium, characterized in that a computer program is stored on the computer-readable storage medium, and when the computer program is executed by a processor, the load transient voltage instability judgment method based on power factor positive feedback as claimed in claim 1 is executed.
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