CN103248049B

CN103248049B - Containing the acquisition methods in DFIG wind energy turbine set voltage stability domain of electric power system section

Info

Publication number: CN103248049B
Application number: CN201310193899.9A
Authority: CN
Inventors: 马瑞; 秦泽宇
Original assignee: Changsha University of Science and Technology
Current assignee: Changsha University of Science and Technology
Priority date: 2013-05-22
Filing date: 2013-05-22
Publication date: 2016-02-03
Anticipated expiration: 2033-05-22
Also published as: CN103248049A

Abstract

The invention discloses a method for calculating the tangent plane of the voltage stability domain of a power system containing a DFIG wind farm. - The corrected continuum power flow algorithm determines a static voltage stability boundary trajectory. When using the continuum power flow method, the Jacobian matrix of the prediction step and the correction step are modified, and the constraint function of the DFIG wind farm is added to the Jacobian matrix; Finally, by substituting the parameters linearly related to the two-dimensional parameters and calculating the tangent plane point method equation, the expression of the tangent plane in the safe domain of the DFIG power system is constructed, so that the system voltage after the DFIG wind farm is fully injected The stability analysis is intuitive and reliable, and provides data support for analyzing the static voltage stability of the power grid with the security domain.

Description

Obtaining method of tangent plane in voltage stability domain of power system with DFIG wind farm

技术领域technical field

本发明属于电力系统分析及规划领域，涉及DFIG风电场、电力系统静态电压稳定域切平面的获取方法。The invention belongs to the field of power system analysis and planning, and relates to a DFIG wind farm and a method for obtaining a tangent plane in a static voltage stability domain of a power system.

背景技术Background technique

风力发电是风能利用的重要形式，风能是可再生、无污染、能量大、前景广的能源，大力发展清洁能源是世界各国的战略选择。风具有随机性和不确定性，这就使电网大规模消纳风电具有一定难度。而应用安全域的方法应用到含风电场的电力系统中，可通过追踪系统运行点与安全域边界来提供安全裕度和最优控制信息，从而使电力系统在线实时安全监视、防御与控制更科学和更有效。文献《电力系统安全域方法研究述评》概述了安全域分类与分层关系，以及安全域方法的相关应用。文献《CalculatingSteady-StateOperatingConditionsforDoubly-FedInductionGeneratorWindTurbines》提出了一种双馈感应发电机(DoublyFedInductionGenerator，以下简称DFIG)模型的建立。目前，基于DFIG的风电场已经开始并网发电，但基于安全域切平面方法研究DFIG风电场注入后电力系统电压稳定性的甚少，而电网对注入后电力系统电压稳定性有很高要求，所以研究DFIG风电场电力系统静态电压稳定域切平面对预警电网安全有着现实意义。Wind power generation is an important form of wind energy utilization. Wind energy is a renewable, pollution-free, high-energy, and promising energy source. It is a strategic choice for all countries in the world to vigorously develop clean energy. Wind is random and uncertain, which makes it difficult for the grid to absorb wind power on a large scale. The method of applying the safety domain is applied to the power system including wind farms, which can provide safety margin and optimal control information by tracking the system operating point and the boundary of the safety domain, so that the online real-time security monitoring, defense and control of the power system are more accurate. scientific and more effective. The literature "Review of Research on Security Domain Methods in Power Systems" summarizes the classification and hierarchical relationship of security domains, as well as the related applications of security domain methods. The document "Calculating Steady-State Operating Conditions for Doubly-Fed Induction Generator Wind Turbines" proposes the establishment of a doubly fed induction generator (Doubly Fed Induction Generator, hereinafter referred to as DFIG) model. At present, wind farms based on DFIG have begun to be connected to the grid to generate electricity, but there are few studies on the voltage stability of the power system after the injection of the DFIG wind farm based on the safe domain tangent plane method, and the power grid has high requirements for the voltage stability of the power system after injection. Therefore, the study of the tangent plane in the static voltage stability domain of the DFIG wind farm power system has practical significance for the early warning of the power grid security.

发明内容Contents of the invention

(一)要解决的技术问题(1) Technical problems to be solved

本发明的目的在于解决大规模DFIG风电机组注入后，电力系统电压稳定性研究的问题。The purpose of the invention is to solve the problem of the research on the voltage stability of the power system after the injection of large-scale DFIG wind turbines.

(二)技术方案(2) Technical solution

现实中，绝大部分风电场所使用的发电机机种一致，如该风电场使用DFIG风电机组，则该风电场将使用同一类型风电机组，而不会与其它类型发电装置混用。本发明提出了一种含DFIG电力系统静态电压稳定安全域切平面求解的方法，该方法首先对DFIG进行数学建模，利用七个DFIG状态变量对模型进行约束；然后利用预测与校正的连续潮流法对电力系统静态电压稳定的二维边界进行追踪，得到一条静态电压稳定边界轨迹，为确定含DFIG电力系统静态电压稳定安全域切平面打下基础；最后通过对与该二维参数呈线性关系参变量的代换以及切平面点法式方程的计算，构建出该含DFIG电力系统安全域切平面的表达式。In reality, most wind farms use the same type of generators. If the wind farm uses DFIG wind turbines, the wind farm will use the same type of wind turbines and will not mix them with other types of power generation devices. The present invention proposes a method for solving the tangent plane in the static voltage stability safety region of a power system containing DFIG. The method first carries out mathematical modeling on DFIG, and uses seven DFIG state variables to constrain the model; then uses the continuous power flow predicted and corrected The two-dimensional boundary of the static voltage stability of the power system is traced by the method, and a static voltage stability boundary trajectory is obtained, which lays the foundation for determining the tangent plane of the static voltage stability safety domain of the power system containing DFIG; The substitution of variables and the calculation of the normal equation of the tangent plane point construct the expression of the tangent plane of the power system security region containing DFIG.

(三)有益效果(3) Beneficial effects

本发明解决了大规模DFIG风电机组注入后，电力系统电压稳定性研究的问题。The invention solves the problem of researching the voltage stability of the power system after the injection of large-scale DFIG wind turbines.

附图说明Description of drawings

图1是本发明的稳定域切平面获取方法计算流程示意图。Fig. 1 is a schematic diagram of the calculation flow of the method for obtaining the tangent plane in the stable domain of the present invention.

具体实施方式detailed description

下面结合附图和实施例，对本发明的具体实施方式做进一步描述。以下实施例仅用于说明本发明，但不用来限制本发明的范围。The specific implementation manner of the present invention will be further described below in conjunction with the drawings and embodiments. The following examples are only used to illustrate the present invention, but not to limit the scope of the present invention.

如图1所示的计算流程。The calculation process shown in Figure 1.

本发明包括以下步骤：The present invention comprises the following steps:

1)确定DFIG风电场的电力系统数学模型1) Determine the mathematical model of the power system of the DFIG wind farm

1.1)首先认为所有的双馈风电机组为相同型号的并且风电场周围的风速均匀分布，所以可以用一个双馈风机模型表示风电场。其中，双馈风电机的机械能输出表达式为1.1) Firstly, it is considered that all DFIGs are of the same type and the wind speed around the wind farm is evenly distributed, so a DFIG model can be used to represent the wind farm. Among them, the mechanical energy output expression of DFIG is

${P P}_{m m} = = \frac{11}{22} {ρAC ρAC}_{p p} {U u}^{33} - - - - - - ((11))$

其中，ρ为空气密度；A为风力机的扫掠面积；U为风速；C_p为风力机的风能利用系数，表明风轮从风中获得的有用风能比例，与尖速比T_tsr有关。Among them, ρ is the air density; A is the swept area of the wind turbine; U is the wind speed; C _p is the wind energy utilization coefficient of the wind turbine, indicating the useful wind energy ratio obtained by the wind rotor from the wind, which is related to the tip speed ratio T _tsr .

1.2)以下为含DFIG风电场电力系统含参潮流方程式：1.2) The following is the power flow equation with parameters of the wind farm power system including DFIG:

${f f}_{11} = = ((11 + + λ λ)) {P P}_{i i} + + {P P}_{i i m m} - - {V V}_{i i} \underset{j j &Element; &Element; i i}{Σ Σ} {V V}_{j j} (({G G}_{i i j j} {cosδ cosδ}_{i i j j} + + {B B}_{i i j j} {sinδ sinδ}_{i i j j})) = = 00$

${f f}_{22} = = ((11 + + λ λ)) {Q Q}_{i i} + + {Q Q}_{i i m m} - - {V V}_{i i} \underset{j j &Element; &Element; i i}{Σ Σ} {V V}_{j j} (({G G}_{i i j j} {sinδ sinδ}_{i i j j} + + {B B}_{i i j j} {cosδ cosδ}_{i i j j})) = = 00$

f₃＝V_scos(θ_s)+R_sI_scos(φ_s)-(X_s+X_m)I_ssin(φ_s)+X_mI_rsin(φ_r)＝0f ₃ ＝V _s cos(θ _s )+R _s I _s cos(φ _s )-(X _s +X _m )I _s sin(φ _s )+X _m I _r sin(φ _r )＝0

f₄＝V_ssin(θ_s)-R_sI_ssin(φ_s)+(X_s+X_m)I_scos(φ_s)-X_mI_rcos(φ_r)＝0f ₄ ＝V _s sin(θ _s )-R _s I _s sin(φ _s )+(X _s +X _m )I _s cos(φ _s )-X _m I _r cos(φ _r )＝0

f₅＝V_rcos(θ_r)-sX_mI_ssin(φ_s)-R_rI_rcos(φ_r)+s(X_s+X_m)I_rsin(φ_r)＝0(2)f ₅ ＝V _r cos(θ _r )-sX _m I _s sin(φ _s )-R _r I _r cos(φ _r )+s(X _s +X _m )I _r sin(φ _r )＝0(2 )

f₆＝V_rsin(θ_r)+sX_mI_scos(φ_s)-R_rI_rsin(φ_r)-s(X_s+X_m)I_rcos(φ_r)＝0f ₆ ＝V _r sin(θ _r )+sX _m I _s cos(φ _s )-R _r I _r sin(φ _r )-s(X _s +X _m )I _r cos(φ _r )＝0

f₇＝P_m-V_sI_scos(θ_s-φ_s)+V_rI_rcos(θ_r-φ_r)＝0f ₇ ＝P _m -V _s I _s cos(θ _s -φ _s )+V _r I _r cos(θ _r -φ _r )＝0

f₈＝Q_m-V_sI_ssin(θ_s-φ_s)＝0f ₈ ＝Q _m -V _s I _s sin(θ _s -φ _s )＝0

${f f}_{99} = = {P P}_{m m} + + {I I}_{s the s}^{22} {R R}_{s the s} + + {I I}_{r r}^{22} {R R}_{r r} + + {P P}_{G G B B,, L L o o s the s s the s} - - k k {((11 - - s the s))}^{33} = = 00$

式中，V_i为节点电压大小，δ_i为节点电压相角，V_s为定子电压大小，θ_s为定子电压相角，V_r为转子电压大小，θ_r为转子电压相角，I_r为转子电流大小，φ_r为转子电流相角，I_s为定子电流大小，φ_s为定子电流相角，s为滑差。In the formula, V _i is the magnitude of the node voltage, δ _i is the phase angle of the node voltage, V _s is the magnitude of the stator voltage, θ _s is the phase angle of the stator voltage, V _r is the magnitude of the rotor voltage, θ _r is the phase angle of the rotor voltage, I _r is the magnitude of the rotor current, φ _r is the phase angle of the rotor current, I _s is the magnitude of the stator current, φ _s is the phase angle of the stator current, and s is the slip.

将含有V_r,θ_r,I_S,φ_S,I_r,φ_r,s七个未知数的七个式子，即式(2)中f₃-f₉加到系统的含参潮流方程中后，对其雅可比矩阵修改，再进行预测-校正的计算，以得到含DFIG电力系统的静态临界稳定点。Add seven formulas containing seven unknowns of V _r , θ _r , I _S , φ _S , I _r , φ _r , s, that is, f ₃ -f ₉ in formula (2) to the system's flow equation with parameters Finally, the Jacobian matrix is modified, and then the prediction-correction calculation is performed to obtain the static critical stability point of the power system containing DFIG.

2)用连续潮流法计算含DFIG电力系统静态电压稳定边界初始点2) Calculating the initial point of the static voltage stability boundary of the power system with DFIG using the continuum power flow method

在引入双馈风机后，系统的含参潮流模型可以记为：After introducing the double-fed fan, the power flow model with parameters of the system can be written as:

f(V_i,δ_i,V_r,θ_r,I_s,φ_s,I_r,φ_r,s,λ,P_m)＝0(3)f(V _i ,δ _i ,V _r ,θ _r ,I _s ,φ _s ,I _r ,φ _r ,s,λ,P _m )＝0(3)

式中，V_i,δ_i,V_r,θ_r,I_s,φ_s,I_r,φ_r,s为系统的状态向量；λ为反映系统发电机有功、无功功率注入和负荷变化的向量；p_m为风电场机械功率注入向量(即系统可变参数向量)。In the formula, V _i , δ _i , V _r , θ _r , I _s , φ _s , I _r , φ _r , s are the state vectors of the system; vector; pm is the mechanical power injection _vector of the wind farm (that is, the variable parameter vector of the system).

先固定p_m不变，λ为自由变化参数，再通过连续潮流法描绘出一条有功功率和电压的P-U曲线，并且得出一个鞍结分岔点(SaddleNodeBifurcation，以下简称SNB点)，即为初始边界点。以下为连续潮流计算方法。First fix p _m constant, λ is a freely variable parameter, and then draw a PU curve of active power and voltage by continuous power flow method, and obtain a saddle node bifurcation point (SaddleNodeBifurcation, hereinafter referred to as SNB point), which is the initial boundary point. The following is the continuous power flow calculation method.

2.1)预测步的计算2.1) Calculation of prediction step

首先要确定变量的预测方向。以切线方向为例，对式(3)求微分，得The first step is to determine the direction of prediction of the variables. Take the tangent direction as an example, and differentiate the formula (3), we get

$\begin{matrix} {f f}_{{V V}_{i i}} {d d}_{{V V}_{i i}} + + {f f}_{{δ δ}_{i i}} {d d}_{{δ δ}_{i i}} + + {f f}_{{V V}_{r r}} {d d}_{{V V}_{r r}} + + {f f}_{{θ θ}_{r r}} {d d}_{{θ θ}_{r r}} + + {f f}_{{I I}_{s the s}} {d d}_{{I I}_{s the s}} + + {f f}_{{φ φ}_{s the s}} {d d}_{{φ φ}_{s the s}} \\ + + {f f}_{{I I}_{r r}} {d d}_{{I I}_{r r}} + + {f f}_{{φ φ}_{r r}} {d d}_{{φ φ}_{r r}} + + {f f}_{s the s} {d d}_{s the s} + + {f f}_{s the s} {d d}_{s the s} + + {f f}_{λ λ} {d d}_{λ λ} = = 00 \end{matrix} - - - - - - ((44))$

如果当前解处在解曲线的平凡位置，即雅可比矩阵非奇异，则以λ作为参数化变量，在临界点之前λ的变化方向为+1，在临界点之后λ的变化方向为-1。可得下式If the current solution is in the ordinary position of the solution curve, that is, the Jacobian matrix is non-singular, then λ is used as a parameterized variable, and the direction of change of λ before the critical point is +1, and the direction of change of λ after the critical point is -1. The following formula can be obtained

$[\begin{matrix} {f f}_{11 {V V}_{i i}} & {f f}_{11 {δ δ}_{i i}} & {f f}_{11 {V V}_{r r}} & {f f}_{11 {θ θ}_{r r}} & {f f}_{11 {I I}_{S S}} & {f f}_{11 {φ φ}_{S S}} & {f f}_{11 {I I}_{r r}} & {f f}_{11 {φ φ}_{r r}} & {f f}_{11 s the s} & {f f}_{11 λ λ} \\ {f f}_{22 {V V}_{i i}} & {f f}_{22 {δ δ}_{i i}} & {f f}_{22 {V V}_{r r}} & {f f}_{22 {θ θ}_{r r}} & {f f}_{22 {I I}_{S S}} & {f f}_{22 {φ φ}_{S S}} & {f f}_{22 {I I}_{r r}} & {f f}_{22 {φ φ}_{r r}} & {f f}_{22 s the s} & {f f}_{22 λ λ} \\ {f f}_{33 {V V}_{i i}} & {f f}_{33 {δ δ}_{i i}} & {f f}_{33 {V V}_{r r}} & {f f}_{33 {θ θ}_{r r}} & {f f}_{33 {I I}_{S S}} & {f f}_{33 {φ φ}_{S S}} & {f f}_{33 {I I}_{r r}} & {f f}_{33 {φ φ}_{r r}} & {f f}_{33 s the s} & {f f}_{33 λ λ} \\ {f f}_{44 {V V}_{i i}} & {f f}_{44 {δ δ}_{i i}} & {f f}_{44 {V V}_{r r}} & {f f}_{44 {θ θ}_{r r}} & {f f}_{44 {I I}_{S S}} & {f f}_{44 {φ φ}_{S S}} & {f f}_{44 {I I}_{r r}} & {f f}_{44 {φ φ}_{r r}} & {f f}_{44 s the s} & {f f}_{44 λ λ} \\ {f f}_{55 {V V}_{i i}} & {f f}_{55 {δ δ}_{i i}} & {f f}_{55 {V V}_{r r}} & {f f}_{55 {θ θ}_{r r}} & {f f}_{55 {I I}_{S S}} & {f f}_{55 {φ φ}_{S S}} & {f f}_{55 {I I}_{r r}} & {f f}_{55 {φ φ}_{r r}} & {f f}_{55 s the s} & {f f}_{55 λ λ} \\ {f f}_{66 {V V}_{i i}} & {f f}_{66 {δ δ}_{i i}} & {f f}_{66 {V V}_{r r}} & {f f}_{66 {θ θ}_{r r}} & {f f}_{66 {I I}_{S S}} & {f f}_{66 {φ φ}_{S S}} & {f f}_{66 {I I}_{r r}} & {f f}_{66 {φ φ}_{r r}} & {f f}_{66 s the s} & {f f}_{66 λ λ} \\ {f f}_{77 {V V}_{i i}} & {f f}_{77 {δ δ}_{i i}} & {f f}_{77 {V V}_{r r}} & {f f}_{77 {θ θ}_{r r}} & {f f}_{77 {I I}_{S S}} & {f f}_{77 {φ φ}_{S S}} & {f f}_{77 {I I}_{r r}} & {f f}_{77 {φ φ}_{r r}} & {f f}_{77 s the s} & {f f}_{77 λ λ} \\ {f f}_{88 {V V}_{i i}} & {f f}_{88 {δ δ}_{i i}} & {f f}_{88 {V V}_{r r}} & {f f}_{88 {θ θ}_{r r}} & {f f}_{88 {I I}_{S S}} & {f f}_{88 {φ φ}_{S S}} & {f f}_{88 {I I}_{r r}} & {f f}_{88 {φ φ}_{r r}} & {f f}_{88 s the s} & {f f}_{88 λ λ} \\ {f f}_{99 {V V}_{i i}} & {f f}_{99 {δ δ}_{i i}} & {f f}_{99 {V V}_{r r}} & {f f}_{99 {θ θ}_{r r}} & {f f}_{99 {I I}_{S S}} & {f f}_{99 {φ φ}_{S S}} & {f f}_{99 {I I}_{r r}} & {f f}_{99 {φ φ}_{r r}} & {f f}_{99 s the s} & {f f}_{99 λ λ} \\ 00 & 00 & 00 & 00 & 00 & 00 & 00 & 00 & 00 & 11 \end{matrix}] [\begin{matrix} {d d}_{{V V}_{i i}} \\ {d d}_{{δ δ}_{i i}} \\ {d d}_{{V V}_{r r}} \\ {d d}_{{θ θ}_{r r}} \\ {d d}_{{I I}_{s the s}} \\ {d d}_{{φ φ}_{s the s}} \\ {d d}_{{I I}_{r r}} \\ {d d}_{{φ φ}_{r r}} \\ {d d}_{s the s} \\ {d d}_{λ λ} \end{matrix}] = = [\begin{matrix} 00 \\ 00 \\ 00 \\ 00 \\ 00 \\ 00 \\ 00 \\ 00 \\ 00 \\ &PlusMinus; &PlusMinus; 11 \end{matrix}] - - - - - - ((55))$

由此可确定预测方向。From this the prediction direction can be determined.

如果当前解处在解曲线的位置接近临界点，即雅可比矩阵接近奇异，式(5)的系数矩阵也将接近奇异，则应选择状态变量(例如变化率最大的节点k的电压)作为参数化变化量，而将λ作为普通变化量，状态变量的斜率作为切线方向，此时由下式可确定预测方向：If the current solution is close to the critical point at the position of the solution curve, that is, the Jacobian matrix is close to singularity, and the coefficient matrix of formula (5) will also be close to singularity, then the state variable (such as the voltage of node k with the largest rate of change) should be selected as the parameter λ is used as the ordinary variation, and the slope of the state variable is used as the tangent direction. At this time, the prediction direction can be determined by the following formula:

$[\begin{matrix} {f f}_{11 {V V}_{i i}} & {f f}_{11 {δ δ}_{i i}} & {f f}_{11 {V V}_{r r}} & {f f}_{11 {θ θ}_{r r}} & {f f}_{11 {I I}_{S S}} & {f f}_{11 {φ φ}_{S S}} & {f f}_{11 {I I}_{r r}} & {f f}_{11 {φ φ}_{r r}} & {f f}_{11 s the s} & {f f}_{11 λ λ} \\ {f f}_{22 {V V}_{i i}} & {f f}_{22 {δ δ}_{i i}} & {f f}_{22 {V V}_{r r}} & {f f}_{22 {θ θ}_{r r}} & {f f}_{22 {I I}_{S S}} & {f f}_{22 {φ φ}_{S S}} & {f f}_{22 {I I}_{r r}} & {f f}_{22 {φ φ}_{r r}} & {f f}_{22 s the s} & {f f}_{22 λ λ} \\ {f f}_{33 {V V}_{i i}} & {f f}_{33 {δ δ}_{i i}} & {f f}_{33 {V V}_{r r}} & {f f}_{33 {θ θ}_{r r}} & {f f}_{33 {I I}_{S S}} & {f f}_{33 {φ φ}_{S S}} & {f f}_{33 {I I}_{r r}} & {f f}_{33 {φ φ}_{r r}} & {f f}_{33 s the s} & {f f}_{33 λ λ} \\ {f f}_{44 {V V}_{i i}} & {f f}_{44 {δ δ}_{i i}} & {f f}_{44 {V V}_{r r}} & {f f}_{44 {θ θ}_{r r}} & {f f}_{44 {I I}_{S S}} & {f f}_{44 {φ φ}_{S S}} & {f f}_{44 {I I}_{r r}} & {f f}_{44 {φ φ}_{r r}} & {f f}_{44 s the s} & {f f}_{44 λ λ} \\ {f f}_{55 {V V}_{i i}} & {f f}_{55 {δ δ}_{i i}} & {f f}_{55 {V V}_{r r}} & {f f}_{55 {θ θ}_{r r}} & {f f}_{55 {I I}_{S S}} & {f f}_{55 {φ φ}_{S S}} & {f f}_{55 {I I}_{r r}} & {f f}_{55 {φ φ}_{r r}} & {f f}_{55 s the s} & {f f}_{55 λ λ} \\ {f f}_{66 {V V}_{i i}} & {f f}_{66 {δ δ}_{i i}} & {f f}_{66 {V V}_{r r}} & {f f}_{66 {θ θ}_{r r}} & {f f}_{66 {I I}_{S S}} & {f f}_{66 {φ φ}_{S S}} & {f f}_{66 {I I}_{r r}} & {f f}_{66 {φ φ}_{r r}} & {f f}_{66 s the s} & {f f}_{66 λ λ} \\ {f f}_{77 {V V}_{i i}} & {f f}_{77 {δ δ}_{i i}} & {f f}_{77 {V V}_{r r}} & {f f}_{77 {θ θ}_{r r}} & {f f}_{77 {I I}_{S S}} & {f f}_{77 {φ φ}_{S S}} & {f f}_{77 {I I}_{r r}} & {f f}_{77 {φ φ}_{r r}} & {f f}_{77 s the s} & {f f}_{77 λ λ} \\ {f f}_{88 {V V}_{i i}} & {f f}_{88 {δ δ}_{i i}} & {f f}_{88 {V V}_{r r}} & {f f}_{88 {θ θ}_{r r}} & {f f}_{88 {I I}_{S S}} & {f f}_{88 {φ φ}_{S S}} & {f f}_{88 {I I}_{r r}} & {f f}_{88 {φ φ}_{r r}} & {f f}_{88 s the s} & {f f}_{88 λ λ} \\ {f f}_{99 {V V}_{i i}} & {f f}_{99 {δ δ}_{i i}} & {f f}_{99 {V V}_{r r}} & {f f}_{99 {θ θ}_{r r}} & {f f}_{99 {I I}_{S S}} & {f f}_{99 {φ φ}_{S S}} & {f f}_{99 {I I}_{r r}} & {f f}_{99 {φ φ}_{r r}} & {f f}_{99 s the s} & {f f}_{99 λ λ} \\ {e e}_{k k}^{t t} & 00 \end{matrix}] [\begin{matrix} {d d}_{{V V}_{i i}} \\ {d d}_{{δ δ}_{i i}} \\ {d d}_{{V V}_{r r}} \\ {d d}_{{θ θ}_{r r}} \\ {d d}_{{I I}_{s the s}} \\ {d d}_{{φ φ}_{s the s}} \\ {d d}_{{I I}_{r r}} \\ {d d}_{{φ φ}_{r r}} \\ {d d}_{s the s} \\ {d d}_{λ λ} \end{matrix}] = = [\begin{matrix} 00 \\ 00 \\ 00 \\ 00 \\ 00 \\ 00 \\ 00 \\ 00 \\ 00 \\ &PlusMinus; &PlusMinus; 11 \end{matrix}] - - - - - - ((66))$

其中，为第k个元素为+1，其余元素为0的行矢量。应注意式(6)与式(5)的系数矩阵不同。由于选择了状态变量作为参数化变量，即使雅可比矩阵接近奇异(假定其秩是n-1)，也可以证明是(6)的系数矩阵是非奇异的。in, is a row vector whose kth element is +1 and the rest are 0. It should be noted that the coefficient matrix of formula (6) is different from that of formula (5). Since the state variable is chosen as the parameterization variable, even though the Jacobian matrix is close to singular (assuming its rank is n-1), it can be proved that the coefficient matrix of (6) is non-singular.

根据式(5)或式(6)确定的预测方向，可以计算预测点如下：According to the prediction direction determined by formula (5) or formula (6), the prediction point can be calculated as follows:

$[\begin{matrix} {\overset{~ ~}{V V}}_{i i} \\ {\overset{~ ~}{δ δ}}_{i i} \\ {\overset{~ ~}{V V}}_{r r} \\ {\overset{~ ~}{θ θ}}_{r r} \\ {\overset{~ ~}{I I}}_{S S} \\ {\overset{~ ~}{φ φ}}_{S S} \\ {\overset{~ ~}{I I}}_{r r} \\ {\overset{~ ~}{φ φ}}_{r r} \\ \overset{~ ~}{s the s} \\ \overset{~ ~}{λ λ} \end{matrix}] = = [\begin{matrix} {V V}_{i i 00} \\ {δ δ}_{i i 00} \\ {V V}_{r r 00} \\ {θ θ}_{r r 00} \\ {I I}_{S S 00} \\ {φ φ}_{S S 00} \\ {I I}_{r r 00} \\ {φ φ}_{r r 00} \\ {s the s}_{00} \\ {λ λ}_{00} \end{matrix}] + + σ σ [\begin{matrix} {d d}_{{V V}_{i i}} \\ {d d}_{{δ δ}_{i i}} \\ {d d}_{{V V}_{r r}} \\ {d d}_{{θ θ}_{r r}} \\ {d d}_{{I I}_{s the s}} \\ {d d}_{{φ φ}_{S S}} \\ {d d}_{{I I}_{r r}} \\ {d d}_{{φ φ}_{r r}} \\ {d d}_{s the s} \\ {d d}_{λ λ} \end{matrix}] - - - - - - ((77))$

其中，σ为预测步。Among them, σ is the prediction step.

2.2)校正步的计算2.2) Calculation of correction steps

在校正步中，如果预测方向是由式(5)得到的，应先固定λ，采用垂直校正方法，以为初值求解式(1)的潮流方程。以牛顿-拉夫逊法为例，迭代格式如下：In the correction step, if the prediction direction is obtained by formula (5), λ should be fixed first, and the vertical correction method should be adopted to obtain Solve the power flow equation of formula (1) for the initial value. Taking the Newton-Raphson method as an example, the iteration format is as follows:

$[\begin{matrix} {f f}_{11 {V V}_{i i}} & {f f}_{11 {δ δ}_{i i}} & {f f}_{11 {V V}_{r r}} & {f f}_{11 {θ θ}_{r r}} & {f f}_{11 {I I}_{S S}} & {f f}_{11 {φ φ}_{S S}} & {f f}_{11 {I I}_{r r}} & {f f}_{11 {φ φ}_{r r}} & {f f}_{11 s the s} & {f f}_{11 λ λ} \\ {f f}_{22 {V V}_{i i}} & {f f}_{22 {δ δ}_{i i}} & {f f}_{22 {V V}_{r r}} & {f f}_{22 {θ θ}_{r r}} & {f f}_{22 {I I}_{S S}} & {f f}_{22 {φ φ}_{S S}} & {f f}_{22 {I I}_{r r}} & {f f}_{22 {φ φ}_{r r}} & {f f}_{22 s the s} & {f f}_{22 λ λ} \\ {f f}_{33 {V V}_{i i}} & {f f}_{33 {δ δ}_{i i}} & {f f}_{33 {V V}_{r r}} & {f f}_{33 {θ θ}_{r r}} & {f f}_{33 {I I}_{S S}} & {f f}_{33 {φ φ}_{S S}} & {f f}_{33 {I I}_{r r}} & {f f}_{33 {φ φ}_{r r}} & {f f}_{33 s the s} & {f f}_{33 λ λ} \\ {f f}_{44 {V V}_{i i}} & {f f}_{44 {δ δ}_{i i}} & {f f}_{44 {V V}_{r r}} & {f f}_{44 {θ θ}_{r r}} & {f f}_{44 {I I}_{S S}} & {f f}_{44 {φ φ}_{S S}} & {f f}_{44 {I I}_{r r}} & {f f}_{44 {φ φ}_{r r}} & {f f}_{44 s the s} & {f f}_{44 λ λ} \\ {f f}_{55 {V V}_{i i}} & {f f}_{55 {δ δ}_{i i}} & {f f}_{55 {V V}_{r r}} & {f f}_{55 {θ θ}_{r r}} & {f f}_{55 {I I}_{S S}} & {f f}_{55 {φ φ}_{S S}} & {f f}_{55 {I I}_{r r}} & {f f}_{55 {φ φ}_{r r}} & {f f}_{55 s the s} & {f f}_{55 λ λ} \\ {f f}_{66 {V V}_{i i}} & {f f}_{66 {δ δ}_{i i}} & {f f}_{66 {V V}_{r r}} & {f f}_{66 {θ θ}_{r r}} & {f f}_{66 {I I}_{S S}} & {f f}_{66 {φ φ}_{S S}} & {f f}_{66 {I I}_{r r}} & {f f}_{66 {φ φ}_{r r}} & {f f}_{66 s the s} & {f f}_{66 λ λ} \\ {f f}_{77 {V V}_{i i}} & {f f}_{77 {δ δ}_{i i}} & {f f}_{77 {V V}_{r r}} & {f f}_{77 {θ θ}_{r r}} & {f f}_{77 {I I}_{S S}} & {f f}_{77 {φ φ}_{S S}} & {f f}_{77 {I I}_{r r}} & {f f}_{77 {φ φ}_{r r}} & {f f}_{77 s the s} & {f f}_{77 λ λ} \\ {f f}_{88 {V V}_{i i}} & {f f}_{88 {δ δ}_{i i}} & {f f}_{88 {V V}_{r r}} & {f f}_{88 {θ θ}_{r r}} & {f f}_{88 {I I}_{S S}} & {f f}_{88 {φ φ}_{S S}} & {f f}_{88 {I I}_{r r}} & {f f}_{88 {φ φ}_{r r}} & {f f}_{88 s the s} & {f f}_{88 λ λ} \\ {f f}_{99 {V V}_{i i}} & {f f}_{99 {δ δ}_{i i}} & {f f}_{99 {V V}_{r r}} & {f f}_{99 {θ θ}_{r r}} & {f f}_{99 {I I}_{S S}} & {f f}_{99 {φ φ}_{S S}} & {f f}_{99 {I I}_{r r}} & {f f}_{99 {φ φ}_{r r}} & {f f}_{99 s the s} & {f f}_{99 λ λ} \\ 00 & 00 & 00 & 00 & 00 & 00 & 00 & 00 & 00 & 11 \end{matrix}] [\begin{matrix} {Δ Δ}_{{V V}_{i i}} \\ {Δ Δ}_{{δ δ}_{i i}} \\ {Δ Δ}_{{V V}_{r r}} \\ {Δ Δ}_{{θ θ}_{r r}} \\ {Δ Δ}_{{I I}_{s the s}} \\ {Δ Δ}_{{φ φ}_{s the s}} \\ {Δ Δ}_{{I I}_{r r}} \\ {Δ Δ}_{{φ φ}_{r r}} \\ {Δ Δ}_{s the s} \\ {Δ Δ}_{λ λ} \end{matrix}] = = - - [\begin{matrix} {f f}_{11} \\ {f f}_{22} \\ {f f}_{33} \\ {f f}_{44} \\ {f f}_{55} \\ {f f}_{66} \\ {f f}_{77} \\ {f f}_{88} \\ {f f}_{99} \\ 00 \end{matrix}] - - - - - - ((88))$

如果上述潮流计算收敛，则可以得到P-U曲线上的一点，然后开始新的预测步计算。如果潮流发散，有两种对应的措施：其一是减小步长σ用式(7)预测新的点，并用垂直校正法重新用式(8)迭代；另一种办法是选择状态变量(例如变化率最大的节点k的电压)作为参数化变量，将λ作为普通变量，采用水平校正方法解潮流方程，迭代格式如下：If the above power flow calculation converges, a point on the P-U curve can be obtained, and then a new prediction step calculation can be started. If the power flow diverges, there are two corresponding measures: one is to reduce the step size σ to predict a new point using formula (7), and use the vertical correction method to re-use formula (8) to iterate; the other way is to select the state variable ( For example, the voltage of node k with the largest rate of change) is used as a parameterized variable, and λ is used as an ordinary variable, and the horizontal correction method is used to solve the power flow equation. The iterative format is as follows:

$[\begin{matrix} {f f}_{11 {V V}_{i i}} & {f f}_{11 {δ δ}_{i i}} & {f f}_{11 {V V}_{r r}} & {f f}_{11 {θ θ}_{r r}} & {f f}_{11 {I I}_{S S}} & {f f}_{11 {φ φ}_{S S}} & {f f}_{11 {I I}_{r r}} & {f f}_{11 {φ φ}_{r r}} & {f f}_{11 s the s} & {f f}_{11 λ λ} \\ {f f}_{22 {V V}_{i i}} & {f f}_{22 {δ δ}_{i i}} & {f f}_{22 {V V}_{r r}} & {f f}_{22 {θ θ}_{r r}} & {f f}_{22 {I I}_{S S}} & {f f}_{22 {φ φ}_{S S}} & {f f}_{22 {I I}_{r r}} & {f f}_{22 {φ φ}_{r r}} & {f f}_{22 s the s} & {f f}_{22 λ λ} \\ {f f}_{33 {V V}_{i i}} & {f f}_{33 {δ δ}_{i i}} & {f f}_{33 {V V}_{r r}} & {f f}_{33 {θ θ}_{r r}} & {f f}_{33 {I I}_{S S}} & {f f}_{33 {φ φ}_{S S}} & {f f}_{33 {I I}_{r r}} & {f f}_{33 {φ φ}_{r r}} & {f f}_{33 s the s} & {f f}_{33 λ λ} \\ {f f}_{44 {V V}_{i i}} & {f f}_{44 {δ δ}_{i i}} & {f f}_{44 {V V}_{r r}} & {f f}_{44 {θ θ}_{r r}} & {f f}_{44 {I I}_{S S}} & {f f}_{44 {φ φ}_{S S}} & {f f}_{44 {I I}_{r r}} & {f f}_{44 {φ φ}_{r r}} & {f f}_{44 s the s} & {f f}_{44 λ λ} \\ {f f}_{55 {V V}_{i i}} & {f f}_{55 {δ δ}_{i i}} & {f f}_{55 {V V}_{r r}} & {f f}_{55 {θ θ}_{r r}} & {f f}_{55 {I I}_{S S}} & {f f}_{55 {φ φ}_{S S}} & {f f}_{55 {I I}_{r r}} & {f f}_{55 {φ φ}_{r r}} & {f f}_{55 s the s} & {f f}_{55 λ λ} \\ {f f}_{66 {V V}_{i i}} & {f f}_{66 {δ δ}_{i i}} & {f f}_{66 {V V}_{r r}} & {f f}_{66 {θ θ}_{r r}} & {f f}_{66 {I I}_{S S}} & {f f}_{66 {φ φ}_{S S}} & {f f}_{66 {I I}_{r r}} & {f f}_{66 {φ φ}_{r r}} & {f f}_{66 s the s} & {f f}_{66 λ λ} \\ {f f}_{77 {V V}_{i i}} & {f f}_{77 {δ δ}_{i i}} & {f f}_{77 {V V}_{r r}} & {f f}_{77 {θ θ}_{r r}} & {f f}_{77 {I I}_{S S}} & {f f}_{77 {φ φ}_{S S}} & {f f}_{77 {I I}_{r r}} & {f f}_{77 {φ φ}_{r r}} & {f f}_{77 s the s} & {f f}_{77 λ λ} \\ {f f}_{88 {V V}_{i i}} & {f f}_{88 {δ δ}_{i i}} & {f f}_{88 {V V}_{r r}} & {f f}_{88 {θ θ}_{r r}} & {f f}_{88 {I I}_{S S}} & {f f}_{88 {φ φ}_{S S}} & {f f}_{88 {I I}_{r r}} & {f f}_{88 {φ φ}_{r r}} & {f f}_{88 s the s} & {f f}_{88 λ λ} \\ {f f}_{99 {V V}_{i i}} & {f f}_{99 {δ δ}_{i i}} & {f f}_{99 {V V}_{r r}} & {f f}_{99 {θ θ}_{r r}} & {f f}_{99 {I I}_{S S}} & {f f}_{99 {φ φ}_{S S}} & {f f}_{99 {I I}_{r r}} & {f f}_{99 {φ φ}_{r r}} & {f f}_{99 s the s} & {f f}_{99 λ λ} \\ {e e}_{k k}^{t t} & 00 \end{matrix}] [\begin{matrix} {Δ Δ}_{{V V}_{i i}} \\ {Δ Δ}_{{δ δ}_{i i}} \\ {Δ Δ}_{{V V}_{r r}} \\ {Δ Δ}_{{θ θ}_{r r}} \\ {Δ Δ}_{{I I}_{s the s}} \\ {Δ Δ}_{{φ φ}_{s the s}} \\ {Δ Δ}_{{I I}_{r r}} \\ {Δ Δ}_{{φ φ}_{r r}} \\ {Δ Δ}_{s the s} \\ {Δ Δ}_{λ λ} \end{matrix}] = = - - [\begin{matrix} {f f}_{11} \\ {f f}_{22} \\ {f f}_{33} \\ {f f}_{44} \\ {f f}_{55} \\ {f f}_{66} \\ {f f}_{77} \\ {f f}_{88} \\ {f f}_{99} \\ 00 \end{matrix}] - - - - - - ((99))$

在校正步中，如果预测方向本身就是由式(6)得到的，也应按式(9)解潮流方程。In the correction step, if the predicted direction itself is obtained from formula (6), the power flow equation should also be solved according to formula (9).

3)计算SNB点精确值3) Calculate the exact value of the SNB point

精确求解SNB初始点，SNB点的约束方程式可描述为To accurately solve the initial point of SNB, the constraint equation of SNB point can be described as

由SNB点构成的电压稳定域边界面可描述为The boundary surface of the voltage stability domain composed of SNB points can be described as

$\{\begin{matrix} f f (({V V}_{i i},, {δ δ}_{i i},, {V V}_{r r},, {θ θ}_{r r},, {I I}_{s the s},, {φ φ}_{s the s},, {I I}_{r r},, {φ φ}_{r r},, s the s,, λ λ,, {P P}_{m m})) = = 00 \\ {f f}_{{V V}_{i i}} {| |}_{* *} y the y + + {f f}_{{δ δ}_{i i}} {| |}_{* *} y the y + + {f f}_{{V V}_{r r}} {| |}_{* *} y the y + + {f f}_{{θ θ}_{r r}} {| |}_{* *} y the y + + {f f}_{{I I}_{S S}} {| |}_{* *} y the y + + {f f}_{{φ φ}_{S S}} {| |}_{* *} y the y + + {f f}_{{I I}_{r r}} {| |}_{* *} y the y + + {f f}_{{φ φ}_{r r}} {| |}_{* *} y the y + + {f f}_{s the s} {| |}_{* *} y the y = = 00 \\ {y the y}^{t t} y the y = = 11 \end{matrix} - - - - - - ((1010))$

y^t＝[dV_idδ_idV_rdθ_rdI_sdφ_sdI_rdφ_rds]y ^t ＝[dV _i dδ _i dV _r dθ _r dI _s dφ _s dI _r dφ _r ds]

式中，V_i,δ_i,V_r,θ_r,I_S,φ_S,I_r,φ_r,s为系统的n维状态向量；λ为反映系统发电机有功、无功功率注入和负荷变化的向量；P_m为风电场机械功率注入向量(即系统可变参数向量)，此时先将P_m值固定；y为潮流方程雅可比矩阵的右特征向量。以连续潮流得到的解为初值，用牛顿—拉夫逊法进行求解方程变量。精确得出初始点。In the formula, V _i , δ _i , V _r , θ _r , I _S , φ _S , I _r , φ _r , s are n-dimensional state vectors of the system; The variable vector; P _m is the mechanical power injection vector of the wind farm (that is, the variable parameter vector of the system), at this time, the value of P _m is fixed first; y is the right eigenvector of the Jacobian matrix of the power flow equation. Taking the solution obtained by the continuous power flow as the initial value, the Newton-Raphson method is used to solve the equation variables. Get the initial point exactly.

4)计算含有DFIG电力系统稳定域的SNB点轨迹4) Calculate the SNB point trajectory containing the stable domain of the DFIG power system

该稳定域SNB点轨迹的算法同样是应用预测-校正方法，将式(10)可简记为The algorithm of the SNB point trajectory in the stable domain is also the application of the prediction-correction method, and the formula (10) can be abbreviated as

φ(z)＝0(11)φ(z)=0(11)

此时at this time

z^t＝[V_iδ_iV_rθ_rI_Sφ_SI_rφ_rsλP_m]∈R²ⁿ⁺²,z ^t ＝[V _i δ _i V _r θ _r I _S φ _S I _r φ _r sλP _m ]∈R ²ⁿ⁺² ,

$φ φ = = [\begin{matrix} f f (({V V}_{i i},, {δ δ}_{i i},, {V V}_{r r},, {θ θ}_{r r},, {I I}_{s the s},, {φ φ}_{s the s},, {I I}_{r r},, {φ φ}_{r r},, s the s,, λ λ,, {P P}_{m m})) \\ {f f}_{{V V}_{i i}} {| |}_{* *} y the y + + {f f}_{{δ δ}_{i i}} {| |}_{* *} y the y + + {f f}_{{V V}_{r r}} {| |}_{* *} y the y + + {f f}_{{θ θ}_{r r}} {| |}_{* *} y the y + + {f f}_{{I I}_{S S}} {| |}_{* *} y the y + + {f f}_{{φ φ}_{S S}} {| |}_{* *} y the y + + {f f}_{{I I}_{r r}} {| |}_{* *} y the y + + {f f}_{{φ φ}_{r r}} {| |}_{* *} y the y + + {f f}_{s the s} {| |}_{* *} y the y \\ {y the y}^{t t} y the y - - 11 \end{matrix}] : : {R R}^{22 n no + + 22} &RightArrow; &Right Arrow; {R R}^{22 n no + + 11}$

由上式所确定的雅可比矩阵的维数为(2n+1)×(2n+2)，因此加入一个参数化方程The dimension of the Jacobian matrix determined by the above formula is (2n+1)×(2n+2), so adding a parameterized equation

(z-z₁)^tv＝τ(12)(zz ₁ ) ^t v=τ(12)

式中，v为z₁点的切向量，z₀为初始点，τ为步长。v是由下式确定的：In the formula, v is the tangent vector of point z ₁ , z ₀ is the initial point, and τ is the step size. v is determined by:

4.1)预测步的计算4.1) Calculation of prediction step

首先假定由步骤2)已经计算得到一点z₀在该电力系统稳定域SNB点轨迹上。从该点开始进行预测，由下式可确定预测方向：First assume that a point z ₀ has been calculated by step 2) and is on the SNB point locus of the power system stability domain. From this point onwards, the prediction direction can be determined by the following formula:

$[\begin{matrix} {f f}_{11 {V V}_{i i}} & {f f}_{11 {δ δ}_{i i}} & {f f}_{11 {V V}_{r r}} & {f f}_{11 {θ θ}_{r r}} & {f f}_{11 {I I}_{S S}} & {f f}_{11 {φ φ}_{S S}} & {f f}_{11 {I I}_{r r}} & {f f}_{11 {φ φ}_{r r}} & {f f}_{11 s the s} & 00 & {f f}_{11 λ λ} & {f f}_{11 {P P}_{m m}} \\ {f f}_{22 {V V}_{i i}} & {f f}_{22 {δ δ}_{i i}} & {f f}_{22 {V V}_{r r}} & {f f}_{22 {θ θ}_{r r}} & {f f}_{22 {I I}_{S S}} & {f f}_{22 {φ φ}_{S S}} & {f f}_{22 {I I}_{r r}} & {f f}_{22 {φ φ}_{r r}} & {f f}_{22 s the s} & 00 & {f f}_{22 λ λ} & {f f}_{22 {P P}_{m m}} \\ {f f}_{33 {V V}_{i i}} & {f f}_{33 {δ δ}_{i i}} & {f f}_{33 {V V}_{r r}} & {f f}_{33 {θ θ}_{r r}} & {f f}_{33 {I I}_{S S}} & {f f}_{33 {φ φ}_{S S}} & {f f}_{33 {I I}_{r r}} & {f f}_{33 {φ φ}_{r r}} & {f f}_{33 s the s} & 00 & {f f}_{33 λ λ} & {f f}_{33 {P P}_{m m}} \\ {f f}_{44 {V V}_{i i}} & {f f}_{44 {δ δ}_{i i}} & {f f}_{44 {V V}_{r r}} & {f f}_{44 {θ θ}_{r r}} & {f f}_{44 {I I}_{S S}} & {f f}_{44 {φ φ}_{S S}} & {f f}_{44 {I I}_{r r}} & {f f}_{44 {φ φ}_{r r}} & {f f}_{44 s the s} & 00 & {f f}_{44 λ λ} & {f f}_{44 {P P}_{m m}} \\ {f f}_{55 {V V}_{i i}} & {f f}_{55 {δ δ}_{i i}} & {f f}_{55 {V V}_{r r}} & {f f}_{55 {θ θ}_{r r}} & {f f}_{55 {I I}_{S S}} & {f f}_{55 {φ φ}_{S S}} & {f f}_{55 {I I}_{r r}} & {f f}_{55 {φ φ}_{r r}} & {f f}_{55 s the s} & 00 & {f f}_{55 λ λ} & {f f}_{55 {P P}_{m m}} \\ {f f}_{66 {V V}_{i i}} & {f f}_{66 {δ δ}_{i i}} & {f f}_{66 {V V}_{r r}} & {f f}_{66 {θ θ}_{r r}} & {f f}_{66 {I I}_{S S}} & {f f}_{66 {φ φ}_{S S}} & {f f}_{66 {I I}_{r r}} & {f f}_{66 {φ φ}_{r r}} & {f f}_{66 s the s} & 00 & {f f}_{66 λ λ} & {f f}_{66 {P P}_{m m}} \\ {f f}_{77 {V V}_{i i}} & {f f}_{77 {δ δ}_{i i}} & {f f}_{77 {V V}_{r r}} & {f f}_{77 {θ θ}_{r r}} & {f f}_{77 {I I}_{S S}} & {f f}_{77 {φ φ}_{S S}} & {f f}_{77 {I I}_{r r}} & {f f}_{77 {φ φ}_{r r}} & {f f}_{77 s the s} & 00 & {f f}_{77 λ λ} & {f f}_{77 {P P}_{m m}} \\ {f f}_{88 {V V}_{i i}} & {f f}_{88 {δ δ}_{i i}} & {f f}_{88 {V V}_{r r}} & {f f}_{88 {θ θ}_{r r}} & {f f}_{88 {I I}_{S S}} & {f f}_{88 {φ φ}_{S S}} & {f f}_{88 {I I}_{r r}} & {f f}_{88 {φ φ}_{r r}} & {f f}_{88 s the s} & 00 & {f f}_{88 λ λ} & {f f}_{88 {P P}_{m m}} \\ {f f}_{99 {V V}_{i i}} & {f f}_{99 {δ δ}_{i i}} & {f f}_{99 {V V}_{r r}} & {f f}_{99 {θ θ}_{r r}} & {f f}_{99 {I I}_{S S}} & {f f}_{99 {φ φ}_{S S}} & {f f}_{99 {I I}_{r r}} & {f f}_{99 {φ φ}_{r r}} & {f f}_{99 s the s} & 00 & {f f}_{99 λ λ} & {f f}_{99 {P P}_{m m}} \\ \frac{\partial \partial g g}{\partial \partial {V V}_{i i}} & \frac{\partial \partial g g}{\partial \partial {δ δ}_{i i}} & \frac{\partial \partial g g}{\partial \partial {V V}_{r r}} & \frac{\partial \partial g g}{\partial \partial {θ θ}_{r r}} & \frac{\partial \partial g g}{\partial \partial {I I}_{S S}} & \frac{\partial \partial g g}{\partial \partial {φ φ}_{S S}} & \frac{\partial \partial g g}{\partial \partial {I I}_{r r}} & \frac{\partial \partial g g}{\partial \partial {φ φ}_{r r}} & \frac{\partial \partial g g}{\partial \partial s the s} & \frac{\partial \partial g g}{\partial \partial y the y} & \frac{\partial \partial g g}{\partial \partial λ λ} & \frac{\partial \partial g g}{\partial \partial {P P}_{m m}} \\ 00 & 00 & 00 & 00 & 00 & 00 & 00 & 00 & 00 & 22 {y the y}^{t t} & 00 & 00 \\ {ΔV ΔV}_{i i} & {Δδ Δδ}_{i i} & {ΔV ΔV}_{r r} & {Δθ Δθ}_{r r} & {ΔI ΔI}_{S S} & {Δφ Δφ}_{S S} & {ΔI ΔI}_{r r} & {Δφ Δφ}_{r r} & Δ Δ s the s & {Δy Δy}^{t t} & Δ Δ λ λ & {ΔP ΔP}_{m m} \end{matrix}] [\begin{matrix} {d d}_{{V V}_{i i}} \\ {d d}_{{δ δ}_{i i}} \\ {d d}_{{V V}_{r r}} \\ {d d}_{{θ θ}_{r r}} \\ {d d}_{{I I}_{S S}} \\ {d d}_{{φ φ}_{S S}} \\ {d d}_{{I I}_{r r}} \\ {d d}_{{φ φ}_{r r}} \\ {d d}_{s the s} \\ {d d}_{y the y} \\ {d d}_{λ λ} \\ {d d}_{{P P}_{m m}} \end{matrix}] = = - - [\begin{matrix} 00 \\ 00 \\ 00 \\ 00 \\ 00 \\ 00 \\ 00 \\ 00 \\ 00 \\ 00 \\ 00 \\ &PlusMinus; &PlusMinus; 11 \end{matrix}] --- --- ((1616))$

根据(14)所确定的预测方向，可以计算预测点如下：According to the prediction direction determined in (14), the prediction point can be calculated as follows:

$[\begin{matrix} {\overset{~ ~}{V V}}_{i i} \\ {\overset{~ ~}{δ δ}}_{i i} \\ {\overset{~ ~}{V V}}_{r r} \\ {\overset{~ ~}{θ θ}}_{r r} \\ {\overset{~ ~}{I I}}_{S S} \\ {φ φ}_{S S} \\ {\overset{~ ~}{I I}}_{r r} \\ {\overset{~ ~}{φ φ}}_{r r} \\ \overset{~ ~}{s the s} \\ \overset{~ ~}{y the y} \\ \overset{~ ~}{λ λ} \\ {\overset{~ ~}{P P}}_{m m} \end{matrix}] = = [\begin{matrix} {V V}_{i i 00} \\ {δ δ}_{i i 00} \\ {V V}_{r r 00} \\ {θ θ}_{r r 00} \\ {I I}_{S S 00} \\ {φ φ}_{S S 00} \\ {I I}_{r r 00} \\ {φ φ}_{r r 00} \\ {s the s}_{00} \\ {y the y}_{00} \\ {λ λ}_{00} \\ {P P}_{m m 00} \end{matrix}] + + τ τ [\begin{matrix} {d d}_{{V V}_{i i}} \\ {d d}_{{δ δ}_{i i}} \\ {d d}_{{V V}_{r r}} \\ {d d}_{{θ θ}_{r r}} \\ {d d}_{{I I}_{S S}} \\ {d d}_{{φ φ}_{S S}} \\ {d d}_{{I I}_{r r}} \\ {d d}_{{φ φ}_{r r}} \\ {d d}_{s the s} \\ {d d}_{y the y} \\ {d d}_{λ λ} \\ {d d}_{{P P}_{m m}} \end{matrix}] - - - - - - ((1515))$

式中，V_i,δ_i,V_r,θ_r,I_S,φ_S,I_r,φ_r,s为系统的n维状态向量；y为潮流方程雅可比矩阵的右特征向量；λ为反映系统发电机有功、无功功率注入和负荷变化的向量；p_m为风电场机械功率注入向量(即系统可变参数向量)；τ为预测步长。In the formula, V _i , δ _i , V _r , θ _r , I _S , φ _S , I _r , φ _r , s are the n-dimensional state vectors of the system; y is the right eigenvector of the Jacobian matrix of the power flow equation; λ is The vector reflecting the system generator active power, reactive power injection and load change; pm is the mechanical power injection vector of the wind farm (that is, the variable parameter vector of the system); _τ is the prediction step size.

4.2)校正步的计算4.2) Calculation of correction steps

在校正格式中，增加了一维校正方程与式(10)联立得校正方程In the correction format, the one-dimensional correction equation and formula (10) are added to obtain the correction equation

$[\begin{matrix} {f f}_{11 {V V}_{i i}} & {f f}_{11 {δ δ}_{i i}} & {f f}_{11 {V V}_{r r}} & {f f}_{11 {θ θ}_{r r}} & {f f}_{11 {I I}_{S S}} & {f f}_{11 {φ φ}_{S S}} & {f f}_{11 {I I}_{r r}} & {f f}_{11 {φ φ}_{r r}} & {f f}_{11 s the s} & 00 & {f f}_{11 λ λ} & {f f}_{11 {P P}_{m m}} \\ {f f}_{22 {V V}_{i i}} & {f f}_{22 {δ δ}_{i i}} & {f f}_{22 {V V}_{r r}} & {f f}_{22 {θ θ}_{r r}} & {f f}_{22 {I I}_{S S}} & {f f}_{22 {φ φ}_{S S}} & {f f}_{22 {I I}_{r r}} & {f f}_{22 {φ φ}_{r r}} & {f f}_{22 s the s} & 00 & {f f}_{22 λ λ} & {f f}_{22 {P P}_{m m}} \\ {f f}_{33 {V V}_{i i}} & {f f}_{33 {δ δ}_{i i}} & {f f}_{33 {V V}_{r r}} & {f f}_{33 {θ θ}_{r r}} & {f f}_{33 {I I}_{S S}} & {f f}_{33 {φ φ}_{S S}} & {f f}_{33 {I I}_{r r}} & {f f}_{33 {φ φ}_{r r}} & {f f}_{33 s the s} & 00 & {f f}_{33 λ λ} & {f f}_{33 {P P}_{m m}} \\ {f f}_{44 {V V}_{i i}} & {f f}_{44 {δ δ}_{i i}} & {f f}_{44 {V V}_{r r}} & {f f}_{44 {θ θ}_{r r}} & {f f}_{44 {I I}_{S S}} & {f f}_{44 {φ φ}_{S S}} & {f f}_{44 {I I}_{r r}} & {f f}_{44 {φ φ}_{r r}} & {f f}_{44 s the s} & 00 & {f f}_{44 λ λ} & {f f}_{44 {P P}_{m m}} \\ {f f}_{55 {V V}_{i i}} & {f f}_{55 {δ δ}_{i i}} & {f f}_{55 {V V}_{r r}} & {f f}_{55 {θ θ}_{r r}} & {f f}_{55 {I I}_{S S}} & {f f}_{55 {φ φ}_{S S}} & {f f}_{55 {I I}_{r r}} & {f f}_{55 {φ φ}_{r r}} & {f f}_{55 s the s} & 00 & {f f}_{55 λ λ} & {f f}_{55 {P P}_{m m}} \\ {f f}_{66 {V V}_{i i}} & {f f}_{66 {δ δ}_{i i}} & {f f}_{66 {V V}_{r r}} & {f f}_{66 {θ θ}_{r r}} & {f f}_{66 {I I}_{S S}} & {f f}_{66 {φ φ}_{S S}} & {f f}_{66 {I I}_{r r}} & {f f}_{66 {φ φ}_{r r}} & {f f}_{66 s the s} & 00 & {f f}_{66 λ λ} & {f f}_{66 {P P}_{m m}} \\ {f f}_{77 {V V}_{i i}} & {f f}_{77 {δ δ}_{i i}} & {f f}_{77 {V V}_{r r}} & {f f}_{77 {θ θ}_{r r}} & {f f}_{77 {I I}_{S S}} & {f f}_{77 {φ φ}_{S S}} & {f f}_{77 {I I}_{r r}} & {f f}_{77 {φ φ}_{r r}} & {f f}_{77 s the s} & 00 & {f f}_{77 λ λ} & {f f}_{77 {P P}_{m m}} \\ {f f}_{88 {V V}_{i i}} & {f f}_{88 {δ δ}_{i i}} & {f f}_{88 {V V}_{r r}} & {f f}_{88 {θ θ}_{r r}} & {f f}_{88 {I I}_{S S}} & {f f}_{88 {φ φ}_{S S}} & {f f}_{88 {I I}_{r r}} & {f f}_{88 {φ φ}_{r r}} & {f f}_{88 s the s} & 00 & {f f}_{88 λ λ} & {f f}_{88 {P P}_{m m}} \\ {f f}_{99 {V V}_{i i}} & {f f}_{99 {δ δ}_{i i}} & {f f}_{99 {V V}_{r r}} & {f f}_{99 {θ θ}_{r r}} & {f f}_{99 {I I}_{S S}} & {f f}_{99 {φ φ}_{S S}} & {f f}_{99 {I I}_{r r}} & {f f}_{99 {φ φ}_{r r}} & {f f}_{99 s the s} & 00 & {f f}_{99 λ λ} & {f f}_{99 {P P}_{m m}} \\ \frac{\partial \partial g g}{\partial \partial {V V}_{i i}} & \frac{\partial \partial g g}{\partial \partial {δ δ}_{i i}} & \frac{\partial \partial g g}{\partial \partial {V V}_{r r}} & \frac{\partial \partial g g}{\partial \partial {θ θ}_{r r}} & \frac{\partial \partial g g}{\partial \partial {I I}_{S S}} & \frac{\partial \partial g g}{\partial \partial {φ φ}_{S S}} & \frac{\partial \partial g g}{\partial \partial {I I}_{r r}} & \frac{\partial \partial g g}{\partial \partial {φ φ}_{r r}} & \frac{\partial \partial g g}{\partial \partial s the s} & \frac{\partial \partial g g}{\partial \partial y the y} & \frac{\partial \partial g g}{\partial \partial λ λ} & \frac{\partial \partial g g}{\partial \partial {P P}_{m m}} \\ 00 & 00 & 00 & 00 & 00 & 00 & 00 & 00 & 00 & 22 {y the y}^{t t} & 00 & 00 \\ {ΔV ΔV}_{i i} & {Δδ Δδ}_{i i} & {ΔV ΔV}_{r r} & {Δθ Δθ}_{r r} & {ΔI ΔI}_{S S} & {Δφ Δφ}_{S S} & {ΔI ΔI}_{r r} & {Δφ Δφ}_{r r} & Δ Δ s the s & {Δy Δy}^{t t} & Δ Δ λ λ & {ΔP ΔP}_{m m} \end{matrix}] [\begin{matrix} {Δ Δ}_{{V V}_{i i}} \\ {Δ Δ}_{{δ δ}_{i i}} \\ {Δ Δ}_{{V V}_{r r}} \\ {Δ Δ}_{{θ θ}_{r r}} \\ {Δ Δ}_{{I I}_{S S}} \\ {Δ Δ}_{{φ φ}_{S S}} \\ {Δ Δ}_{{I I}_{r r}} \\ {Δ Δ}_{{φ φ}_{r r}} \\ {Δ Δ}_{s the s} \\ {Δ Δ}_{y the y} \\ {Δ Δ}_{λ λ} \\ {Δ Δ}_{{P P}_{m m}} \end{matrix}] = = - - [\begin{matrix} {f f}_{11} \\ {f f}_{22} \\ {f f}_{33} \\ {f f}_{44} \\ {f f}_{55} \\ {f f}_{66} \\ {f f}_{77} \\ {f f}_{88} \\ {f f}_{99} \\ g g \\ {y the y}^{t t} y the y - - 11 \\ 00 \end{matrix}] --- --- ((1616))$

修正后的变量为The corrected variable is

$[\begin{matrix} {V V}_{i i}^{((n no + + 11))} \\ {δ δ}_{i i}^{((n no + + 11))} \\ {V V}_{r r}^{((n no + + 11))} \\ {θ θ}_{r r}^{((n no + + 11))} \\ {I I}_{S S}^{((n no + + 11))} \\ {φ φ}_{S S}^{((n no + + 11))} \\ {I I}_{r r}^{((n no + + 11))} \\ {φ φ}_{r r}^{((n no + + 11))} \\ {s the s}^{((n no + + 11))} \\ {y the y}^{((n no + + 11))} \\ {λ λ}^{((n no + + 11))} \\ {P P}_{m m}^{((n no + + 11))} \end{matrix}] = = [\begin{matrix} {V V}_{i i}^{((n no))} \\ {δ δ}_{i i}^{((n no))} \\ {V V}_{r r}^{((n no))} \\ {θ θ}_{r r}^{((n no))} \\ {I I}_{S S}^{((n no))} \\ {φ φ}_{S S}^{((n no))} \\ {I I}_{r r}^{((n no))} \\ {φ φ}_{r r}^{((n no))} \\ {s the s}^{((n no))} \\ {y the y}^{((n no))} \\ {λ λ}^{((n no))} \\ {P P}_{m m}^{((n no))} \end{matrix}] + + [\begin{matrix} {ΔV ΔV}_{i i}^{((n no))} \\ {Δδ Δδ}_{i i}^{((n no))} \\ {ΔV ΔV}_{r r}^{((n no))} \\ {Δθ Δθ}_{r r}^{((n no))} \\ {ΔI ΔI}_{S S}^{((n no))} \\ {Δφ Δφ}_{S S}^{((n no))} \\ {ΔI ΔI}_{r r}^{((n no))} \\ {Δφ Δφ}_{r r}^{((n no))} \\ {Δs Δs}^{((n no))} \\ {Δy Δy}^{((n no))} \\ {Δλ Δλ}^{((n no))} \\ {ΔP ΔP}_{m m}^{((n no))} \end{matrix}] - - - - - - ((1717))$

上述预测-校正方法中函数g的定义及相关计算如下：The definition and related calculations of the function g in the above prediction-correction method are as follows:

$\begin{matrix} g g = = {f f}_{{V V}_{i i}} {| |}_{* *} y the y + + {f f}_{{δ δ}_{i i}} {| |}_{* *} y the y + + {f f}_{{V V}_{r r}} {| |}_{* *} y the y + + {f f}_{{θ θ}_{r r}} {| |}_{* *} y the y \\ + + {f f}_{{I I}_{S S}} {| |}_{* *} y the y + + {f f}_{{φ φ}_{S S}} {| |}_{* *} y the y + + {f f}_{{I I}_{r r}} {| |}_{* *} y the y + + {f f}_{{φ φ}_{r r}} {| |}_{* *} y the y + + {f f}_{s the s} {| |}_{* *} y the y = = 00 \end{matrix} - - - - - - ((1818))$

由于上述雅可比矩阵含零元素较多，所以为稀疏矩阵。Since the Jacobian matrix above contains more zero elements, it is a sparse matrix.

在电压稳定域边界上的已知一个SNB点为初始点的情况下，利用该预测-校正法可得到一条含有DFIG电力系统稳定域的SNB点轨迹。Assuming that a SNB point on the boundary of the voltage stability region is known as the initial point, a SNB point trajectory containing the DFIG power system stability region can be obtained by using the prediction-correction method.

5)计算含有DFIG电力系统稳定域的切平面5) Calculate the tangent plane containing the stable domain of DFIG power system

在SNB点处将式(10)线性化得到Linearize equation (10) at the SNB point to get

$\begin{matrix} {f f}_{{V V}_{i i}} {| |}_{* *} {ΔV ΔV}_{i i} + + {f f}_{{δ δ}_{i i}} {| |}_{* *} {Δδ Δδ}_{i i} + + {f f}_{{V V}_{r r}} {| |}_{* *} {ΔV ΔV}_{r r} + + {f f}_{{θ θ}_{r r}} {| |}_{* *} {Δθ Δθ}_{r r} + + {f f}_{{I I}_{S S}} {| |}_{* *} {ΔI ΔI}_{S S} + + {f f}_{{φ φ}_{S S}} {| |}_{* *} {Δφ Δφ}_{S S} \\ + + {f f}_{{I I}_{r r}} {| |}_{* *} {ΔI ΔI}_{r r} + + {f f}_{{φ φ}_{r r}} {| |}_{* *} {Δφ Δφ}_{r r} + + {f f}_{s the s} {| |}_{* *} Δ Δ s the s + + {f f}_{λ λ} {| |}_{* *} Δ Δ λ λ + + {f f}_{{P P}_{m m}} {| |}_{* *} {ΔP ΔP}_{m m} = = 00 \end{matrix} - - - - - - ((1919))$

式中，为系统在相应SNB点处的雅可比矩阵；f_λ|_*和分别为式(10)在该点处对λ和P_m的导数矩阵。In the formula, is the Jacobian matrix of the system at the corresponding SNB point; f _λ | _* and are the derivative matrix of formula (10) with respect to λ and P _m at this point, respectively.

对上式(19)左乘该SNB点处雅可比矩阵零特征值对应的左特征向量ω，得Multiply the above formula (19) by the left eigenvector ω corresponding to the zero eigenvalue of the Jacobian matrix at the SNB point, and get

$\begin{matrix} {ωf ω f}_{{V V}_{i i}} {| |}_{* *} {ΔV ΔV}_{i i} + + {ωf ω f}_{{δ δ}_{i i}} {| |}_{* *} {Δδ Δδ}_{i i} + + {ωf ω f}_{{V V}_{r r}} {| |}_{* *} {ΔV ΔV}_{r r} + + {ωf ω f}_{{θ θ}_{r r}} {| |}_{* *} {Δθ Δθ}_{r r} + + {ωf ω f}_{{I I}_{S S}} {| |}_{* *} {ΔI ΔI}_{S S} + + {ωf ω f}_{{φ φ}_{S S}} {| |}_{* *} {Δφ Δφ}_{S S} \\ + + {ωf ω f}_{{I I}_{r r}} {| |}_{* *} {ΔI ΔI}_{r r} + + {ωf ω f}_{{φ φ}_{r r}} {| |}_{* *} {Δφ Δφ}_{r r} + + {ωf ω f}_{s the s} {| |}_{* *} Δ Δ s the s + + {ωf ω f}_{λ λ} {| |}_{* *} Δ Δ λ λ + + {ωf ω f}_{{P P}_{m m}} {| |}_{* *} {ΔP ΔP}_{m m} = = 00 \end{matrix} - - - - - - ((2020))$

式中，“|_*”表示对应系数的取值来自SNB点。In the formula, "| _* " means that the value of the corresponding coefficient comes from the SNB point.

设L为负荷裕度，即λ|_*＝λ₀+L。又由于式子中SNB处所以上式可化简为Let L be the load margin, that is, λ| _* =λ ₀ +L. And because of the position of SNB in the formula, the above formula can be simplified as

${ωf ω f}_{λ λ} {| |}_{* *} Δ Δ L L + + {ωf ω f}_{{P P}_{m m}} {| |}_{* *} {ΔP ΔP}_{m m} = = 00 - - - - - - ((21 twenty one))$

其均为零，式(21)可视为L-P_m空间中电压稳定域的局部近似条件，若已知一个SNB点z₁，将该点的对应数代入式(21)中，可得到系数向量该系数向量就是L-P_m空间中的电压稳定域边界在点z₁处的法向量。设z₁在该空间中的坐标为(L₁,P_m1)，则根据点法式方程可得到电压稳定域边界在z₁处的切线表达式为That are all zero, formula (21) can be regarded as a local approximation condition of the voltage stability domain in LP _m space, if a SNB point z ₁ is known, and the corresponding number of this point is substituted into formula (21), the coefficient vector can be obtained The coefficient vector is the normal vector at the point z ₁ of the boundary of the voltage stability domain in LP _m space. Assuming that the coordinates of z ₁ in this space are (L ₁ , P _m1 ), then according to the point normal equation, the expression of the tangent line at the boundary of the voltage stability region at z ₁ can be obtained as

${ωf ω f}_{λ λ} {| |}_{* *}^{11} ((L L - - {L L}_{11})) + + {ωf ω f}_{{P P}_{m m}} {| |}_{* *}^{11} (({P P}_{m m} - - {P P}_{m m 11})) = = 00 - - - - - - ((22 twenty two))$

将式(22)给出的L-P_m空间中电压稳定域边界切平面方程映射到发电机、负荷和DFIG风电场全注入空间，考虑如下关系：Map the tangent plane equation of the voltage stability region boundary in the LP _m space given by Equation (22) to the full injection space of generators, loads and DFIG wind farms, and consider the following relationship:

(1+k_iL)P_i ⁰＝P_i|_*(23)(1+k _i L)P _i ⁰ =P _i | _* (23)

式中k_i为系统各个节点发电机和负荷有功注入的增长方向。将式(23)和式(22)联立，可得到在发电机、负荷和风电场全注入空间中静态电压稳定安全域边界在z₁点的切平面方程In the formula, _ki is the growth direction of active power injection of generators and loads at each node of the system. Combining Equation (23) and Equation (22), the tangent plane equation of the boundary of the static voltage stability safety zone at point z ₁ in the generator, load and wind farm full injection space can be obtained

${Σ Σ}_{i i = = 11}^{n no} {ωf ω f}_{λ λ} {| |}_{* *}^{11} \frac{(({P P}_{i i} {| |}_{* *} - - {P P}_{i i} {| |}_{* *}^{11}))}{{k k}_{i i} {P P}_{i i}^{00}} + + {ωf ω f}_{{P P}_{m m}} {| |}_{* *}^{11} (({P P}_{m m} {| |}_{* *} - - {P P}_{m m} {| |}_{* *}^{11})) = = 00 - - - - - - ((24 twenty four))$

式(24)就是所求解的含DFIG风电场的电力系统静态电压稳定安全域局部切平面解析式。Equation (24) is the local tangent plane analytic equation of the power system static voltage stability safety domain including DFIG wind farms to be solved.

以上实施方式仅用于说明本发明，而并非对本发明的限制，有关技术领域的普通技术人员，在不脱离本发明的精神和范围的情况下，还可以做出各种变化和变型，因此所有等同的技术方案也属于本发明的保护范畴。The above embodiments are only used to illustrate the present invention, but not to limit the present invention. Those of ordinary skill in the relevant technical field can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, all Equivalent technical solutions also belong to the protection category of the present invention.

Claims

1. a method for obtaining the tangent plane of the power system voltage stability domain containing DFIG wind farm, is characterized in that comprising the steps:

1) Mathematically model the DFIG wind farm to obtain the static critical stability point of the DFIG power system;

2) Calculate the approximate value of the saddle junction bifurcation point of the static voltage stability boundary of the power system with DFIG using the continuum power flow method;

3) Use the approximate value of the saddle-node bifurcation point calculated by the continuous power flow as the initial value to calculate the exact value of the saddle-node bifurcation point with an accurate algorithm;

4) Using the calculated saddle node bifurcation point as the initial point, calculate the boundary trajectory containing the stability domain of the DFIG power system;

5) In the full injection space of generators, loads and wind farms, the point normal equation method is used to determine the tangent plane equation of the boundary of the static voltage stability safety region at the known point of the saddle node bifurcation point, and the tangent plane equation contains DFIG Analytical formula of the local tangent plane in the static voltage stability safety region of the power system of the wind farm;

Wherein, the mathematical model of the DFIG wind farm in the step 1) needs to be constrained by an equation containing the state parameter of the wind farm, and a power flow equation containing the parameter is established. In the power flow equation, by modifying the Jacobian matrix, the modified The final Jacobian matrix predicts and corrects to obtain the static critical stable point of the power system containing DFIG;

In the step 4), the boundary equation of the voltage stability region formed by the saddle node bifurcation point needs to call the established power flow equation;

The voltage stability domain boundary surface equation formed by the saddle node bifurcation point is added to the parameterized equation to form a new equation group;

In the equation system for calculating the trajectory of the saddle node bifurcation point in the stability domain of DFIG power system, the prediction-correction method is applied again to track the static voltage stability boundary, and the Jacobian matrix in the new prediction step and correction step is formed.

2. the acquisition method of the power system voltage stability region tangent plane of the wind farm containing DFIG according to claim 1, is characterized in that, in described step 2), use the state parameter power flow model of the DFIG wind farm of the system, to The Jacobian matrix of the prediction step and the correction step of the continuous power flow method are modified, and the state parameters of the DFIG wind farm are added to the corresponding elements of the Jacobian matrix to solve the power flow equation.