CN103840452B

CN103840452B - A kind of bulk power grid method for estimating state introducing PMU measurement information

Info

Publication number: CN103840452B
Application number: CN201410077078.3A
Authority: CN
Inventors: 赵昆; 颜磊; 徐英; 郎燕生; 贾育培; 李强; 鲍福均; 栗向鑫; 贾琳; 王少芳; 白洋; 张印; 邢颖; 马晓忱
Original assignee: State Grid Corp of China SGCC; China Electric Power Research Institute Co Ltd CEPRI; North China Grid Co Ltd
Current assignee: State Grid Corp of China SGCC; China Electric Power Research Institute Co Ltd CEPRI; North China Grid Co Ltd
Priority date: 2014-03-04
Filing date: 2014-03-04
Publication date: 2016-01-20
Anticipated expiration: 2034-03-04
Also published as: CN103840452A

Abstract

The invention provides a method for estimating the state of a large power grid by introducing PMU measurement information, comprising the following steps: judging the algebraic observability of the power system; judging the observability of the PMU measurement information; and performing state estimation of the large power grid. The present invention provides a large power grid state estimation method that introduces PMU measurement information, based on a fast decomposition estimation algorithm, effectively utilizes PMU measurement information, increases measurement redundancy, improves estimation accuracy; and ensures calculation efficiency and calculation speed, Meet the real-time online requirements of the power system.

Description

A State Estimation Method of Large Power Grid Using PMU Measurement Information

技术领域technical field

本发明涉及一种状态估计方法，具体讲涉及一种引入PMU量测信息的大电网状态估计方法。The invention relates to a state estimation method, in particular to a large power grid state estimation method which introduces PMU measurement information.

背景技术Background technique

同步相量测量单元以全球定位系统GPS提供的精确时间为基准，可实现对电力系统各个节点的同步测量，提供大规模互联电力系统在同一参考时间框架下各关键点的实时稳态、动态信息，提高了系统的可观性，并为提高系统的可控性和可靠性提供了新的视角和思路。The synchronized phasor measurement unit takes the precise time provided by the global positioning system (GPS) as a reference, which can realize the synchronous measurement of each node of the power system, and provide real-time steady state and dynamic information of each key point of the large-scale interconnected power system under the same reference time frame , which improves the observability of the system, and provides a new perspective and idea for improving the controllability and reliability of the system.

1988年，Bonneville电力局(BPA)在美国西部电力协调联盟(WesternElectricCoordinatingCouncilregion，WECC，即原WSCC)首次使用了相量测量装置，并对这些在弗吉尼亚理工开发的原型机进行了室内和现场测试。1993年，弗吉尼亚理工成功研制了全球第一台可商用的同步相量测量装置。IEEE电力系统继电保护和控制委员会设立了一个专门委员会，于1995年率先起草了IEEE1344标准(IEEEStandardforSynchrophasorsforpowersystems)，并于2005年修订为IEEEStdPC37.118—2005，为同步相量测量技术的各项细节如同步相量测量方法、通信接口的规则、推荐的标准和可能的应用提供了标准依据。In 1988, the Bonneville Power Authority (BPA) used phasor measurement devices for the first time in the Western Electric Coordinating Council region (WECC, formerly WSCC), and conducted indoor and field tests of these prototypes developed at Virginia Tech. In 1993, Virginia Tech successfully developed the world's first commercially available synchrophasor measurement device. The IEEE Power System Relay Protection and Control Committee set up a special committee, which first drafted the IEEE1344 standard (IEEE Standard for Synchrophasors for power systems) in 1995, and revised it to IEEE StdPC37.118-2005 in 2005, providing details of synchrophasor measurement technology such as Synchronized phasor measurement methods, rules for communication interfaces, recommended standards and possible applications provide the standard basis.

我国相关工作起步于1994年主要有中国电力科学研究院、各所大学和设备生产商从事研究、开发和批量生产，并分别与各电网公司陆续在一些区域电网展开试点应用。1995年中国电力科学研究院与台湾欧华公司共同研制了国内第一台同步相量测量装置，并于1995年在南方电网500kV天广联络线上安装了两台相角测量装置ADX3000，用于监视联络线相角的摆动，广义上可说是我国第一套WAMS(WideAreaMeasurementSystem，广域监测系统)。my country's related work started in 1994. China Electric Power Research Institute, various universities and equipment manufacturers are mainly engaged in research, development and mass production, and they have successively launched pilot applications in some regional power grids with various power grid companies. In 1995, China Electric Power Research Institute and Taiwan Ouhua jointly developed the first synchrophasor measuring device in China, and in 1995, two phase angle measuring devices ADX3000 were installed on the 500kV Tianguang connection line of China Southern Power Grid for It can be said that it is my country's first WAMS (WideAreaMeasurementSystem, wide area monitoring system) in a broad sense to monitor the swing of the phase angle of the tie line.

目前，国内主要电网的WAMS系统均已投入实际运行，据初步估算，我国已投入电网运行的同步相量测量装置超过1000套。已开发或正在研究、开发的WAMS可预期实现的功能主要有两类：At present, the WAMS systems of major domestic power grids have been put into actual operation. According to preliminary estimates, more than 1,000 sets of synchrophasor measurement devices have been put into operation in the power grid in my country. There are two main types of functions that can be expected to be realized by the WAMS that has been developed or is being researched and developed:

（1）基本功能，包括集成相量数据平台(收集与同步各PMU的数据，提供标准数据接口等)、广域动态监视与分析、同步扰动数据记录与反演；(1) Basic functions, including integrated phasor data platform (collecting and synchronizing data of each PMU, providing standard data interface, etc.), wide-area dynamic monitoring and analysis, and synchronous disturbance data recording and inversion;

（2）先进功能，包括发电机运行状态监视、在线低频振荡检测与分析、模型及其参数辨识、仿真校验、混合状态估计、在线扰动辨识、功角稳定预测与告警、动态电压稳定监视、紧急控制框架中的在线预决策、广域保护、广域HVDC阻尼控制等。(2) Advanced functions, including generator running status monitoring, online low-frequency oscillation detection and analysis, model and parameter identification, simulation verification, hybrid state estimation, online disturbance identification, power angle stability prediction and alarm, dynamic voltage stability monitoring, On-line pre-decision in emergency control framework, wide-area protection, wide-area HVDC damping control, etc.

就应用总体水平而言，国内基本上和国外同步;就制造总体水平和生产能力而言，以及WAMS系统的规范标准、技术性能、先进功能、运行管理与规划建设等方面国内与国外相比并不逊色。As far as the overall level of application is concerned, China is basically in sync with foreign countries; as far as the overall level of manufacturing and production capacity are concerned, as well as the normative standards, technical performance, advanced functions, operation management and planning and construction of the WAMS system, domestic and foreign countries are not comparable. Not inferior.

目前，传统线性估计以PQ分解法的最小二乘估计为基础，使用SCADA量测（进行迭代计算。由于SCADA系统仅能提供节点注入功率、支路潮流、电压幅值和电流幅值量测，且存在着数据精度低、同步性差等缺点，难以适应现代大电网对更高的估计精度和更好估计效率的需要，因此，单纯依赖SCADA量测的传统状态估计方法有待改进；传统的非线性状态估计是以加权最小二乘法为基础，根据电力体统的特征，将雅克比矩阵常数化，将有功和无功分解，即快速分解法。在工程合理的精度范围内，快速分解法具有很好的收敛特性，计算速度快又省内存，是一种公认的状态估计优良算法。At present, the traditional linear estimation is based on the least squares estimation of the PQ decomposition method, and uses SCADA measurement (for iterative calculation. Since the SCADA system can only provide node injection power, branch power flow, voltage amplitude and current amplitude measurement, And there are shortcomings such as low data accuracy and poor synchronization, and it is difficult to adapt to the needs of modern large power grids for higher estimation accuracy and better estimation efficiency. Therefore, the traditional state estimation method that relies solely on SCADA measurement needs to be improved; the traditional nonlinear The state estimation is based on the weighted least square method. According to the characteristics of the power system, the Jacobian matrix is constantized, and the active and reactive power are decomposed, that is, the fast decomposition method. Within the reasonable accuracy range of the project, the fast decomposition method has a good It is a well-recognized excellent algorithm for state estimation because of its convergence characteristics, fast calculation speed and memory saving.

随着WAMS技术的发展和应用，WAMS量测数据以其测量精度高，数据严格同步、数据传输延迟小等特点为状态估计增加了新的品质更好的数据源，并且，WAMS实现了广域范围内母线电压和支路电流相量的直接测量，在测量类型上为状态估计提供了额外的量测数据，将会大大缓解状态估计精度和计算工作量这两方面的困难。With the development and application of WAMS technology, WAMS measurement data has added new and better quality data sources for state estimation due to its high measurement accuracy, strict data synchronization, and small data transmission delay. Moreover, WAMS has realized wide-area The direct measurement of the bus voltage and branch current phasor within the range provides additional measurement data for state estimation in terms of measurement types, which will greatly alleviate the difficulties in state estimation accuracy and computational workload.

发明内容Contents of the invention

为了克服上述现有技术的不足，本发明提供一种引入PMU量测信息的大电网状态估计方法，基于快速分解估计算法，有效利用PMU量测信息，增加量测冗余度，提高了估计精度；并保证计算效率和计算速度，满足电力系统的实时在线要求。In order to overcome the shortcomings of the above-mentioned prior art, the present invention provides a large power grid state estimation method that introduces PMU measurement information. Based on the fast decomposition estimation algorithm, the PMU measurement information is effectively used, the measurement redundancy is increased, and the estimation accuracy is improved. ; and ensure the calculation efficiency and calculation speed to meet the real-time online requirements of the power system.

为了实现上述发明目的，本发明采取如下技术方案：In order to realize the above-mentioned purpose of the invention, the present invention takes the following technical solutions:

本发明提供一种引入PMU量测信息的大电网状态估计方法，所述方法包括以下步骤：The present invention provides a large power grid state estimation method that introduces PMU measurement information, and the method includes the following steps:

步骤1：判断电力系统的代数可观性；Step 1: Judging the algebraic observability of the power system;

步骤2：判断PMU量测信息的可观性；Step 2: Judge the observability of PMU measurement information;

步骤3：进行大电网的状态估计。Step 3: Carry out state estimation of the large power grid.

所述步骤1中，对于节点数为n、测量向量维数为m的电力系统，如果该电力系统线性量测模型系数矩阵的秩rank(H)=2n-1，即H满秩，则认为该电力系统代数可观。In the step 1, for a power system with n nodes and a measurement vector dimension of m, if the rank of the coefficient matrix of the linear measurement model of the power system is rank(H)=2n-1, that is, H is full rank, then it is considered The power system algebra is considerable.

所述步骤2中，根据电力系统的代数可观性，判断PMU量测信息的可观性；分为以下情况：In described step 2, according to the algebraic observability of power system, judge the observability of PMU measurement information; Be divided into following situations:

A、若满足rank(H)=2n-1，则表明PMU量测信息完全可观；A. If rank(H)=2n-1 is satisfied, it indicates that the PMU measurement information is completely considerable;

B、若满足rank(H)≥a*(2n-1)，则表明PMU量测信息大量可观，其中a为0.95～0.9；B. If rank(H)≥a*(2n-1) is satisfied, it indicates that the PMU measurement information is considerable, where a is 0.95-0.9;

C、若满足rank(H)<a*(2n-1)，则表明PMU量测信息少量可观；C. If rank(H)<a*(2n-1) is satisfied, it indicates that the PMU measurement information is small and considerable;

D、若满足rank(H)=0，则表明PMU量测信息完全不可观。D. If rank(H)=0 is satisfied, it indicates that the PMU measurement information is completely unobservable.

所述步骤3中，根据PMU量测信息的可观性进行大电网的状态估计分为以下情况：In the step 3, the state estimation of the large power grid according to the observability of the PMU measurement information is divided into the following situations:

A、若PMU量测信息完全可观，则采用直角坐标线性模型进行线性状态估计；A. If the PMU measurement information is completely observable, use the Cartesian coordinate linear model for linear state estimation;

B、若PMU量测信息大量可观，则利用SCADA量测补充PMU不可观测的区域，进行线性状态估计；B. If there is a large amount of PMU measurement information, use SCADA measurement to supplement the unobservable areas of the PMU to perform linear state estimation;

C、若PMU量测信息少量可观，则进行非线性状态估计；C. If the PMU measurement information is small and considerable, perform nonlinear state estimation;

D、PMU量测信息完全不客观，则无需进行引入PMU的线性估计。D. PMU measurement information is not objective at all, so there is no need to perform linear estimation of the PMU.

采用直角坐标线性模型进行线性状态估计具体过程为：The specific process of linear state estimation using Cartesian coordinate linear model is as follows:

采用电压实部和虚部作为状态量，采用节点电压、节点注入电流和支路电流的实部和虚部作为量测量，于是量测方程用线性方程表示为：The real and imaginary parts of the voltage are used as the state quantity, and the real and imaginary parts of the node voltage, node injection current and branch current are used as the quantity measurement, so the measurement equation is expressed as a linear equation:

z＝h(x)+v＝Ax+v（1）z=h(x)+v=Ax+v(1)

其中，z为量测量，x为状态量，v为随机误差，A为一次系数矩阵，h(x)是根据状态量x的量测的计算值，且有 $\frac{&PartialD; h (x)}{&PartialD; x} = A, h (x) = Ax;$ Among them, z is the quantity measurement, x is the state quantity, v is the random error, A is the first-order coefficient matrix, h(x) is the calculated value based on the measurement of the state quantity x, and $\frac{&PartialD; h (x)}{&PartialD; x} = A, h (x) = Ax;$

目标函数表示为：The objective function is expressed as:

J(x)＝[z-Ax]^TR^-1[z-Ax]（2）J(x)＝[z-Ax] ^T R ^-1 [z-Ax] (2)

其中，R^-1为权值矩阵，J(x)为最小二乘目标函数；Among them, R ^-1 is the weight matrix, and J(x) is the least squares objective function;

线性状态估计方程为： ${\hat{x}}^{(n + 1)} = {[\begin{matrix} A^{T} & R^{- 1 (n)} & A \end{matrix}]}^{T} R^{- 1 (n)} z - - - (3)$ The linear state estimation equation is: ${\hat{x}}^{(no + 1)} = {[\begin{matrix} A^{T} & R^{- 1 (no)} & A \end{matrix}]}^{T} R^{- 1 (no)} z - - - (3)$

其中，R^-1(n)为第n次计算的权值矩阵，为第n+1次计算的估计值；Among them, R ^-1(n) is the weight matrix calculated for the nth time, Estimated value calculated for the n+1th time;

计算残差的偏差量有：Calculate the amount of deviation in the residuals Have:

${r r}_{max max}^{((n no + + 11))} = = max max {{r r (({\overset{^^}{x x}}^{((n no + + 11))}))}} - - - - - - ((44))$

其中，为残差，表示为：in, is the residual, expressed as:

$r r (({\overset{^^}{x x}}^{((n no + + 11))})) = = z z - - h h (({\overset{^^}{x x}}^{((n no + + 11))})) - - - - - - ((55))$

其中，为根据n+1次状态估计值，所得到量测计算值；in, is the estimated value based on n+1 states, The measured and calculated values obtained;

由于对电力系统状态估计精度受电流量测精度的影响大，而受电压量测的影响小，故仅计算电流最大的残差，修正电流量测的权重，有Since the accuracy of the state estimation of the power system is greatly affected by the accuracy of the current measurement, but less affected by the voltage measurement, only the largest residual error of the current is calculated, and the weight of the current measurement is corrected.

${R R}^{- - 11 ((n no + + 11))} = = {R R}_{cor cor}^{- - 11 ((n no))} - - - - - - ((66))$

其中，为残差最大值对应的量测的修正权重矩阵，之再进行一次线性估计，直到满足且其中为电压修正量，相角修正量，ε_v和ε_θ是根据精度预设的收敛门槛值；若已对某量测修正，则不再对该量测的权重进行修正。in, is the corrected weight matrix of the measurement corresponding to the maximum value of the residual error, and then perform a linear estimation until it satisfies and in is the voltage correction amount, The phase angle correction amount, ε _v and ε _θ are the convergence threshold values preset according to the accuracy; if a measurement has been corrected, the weight of the measurement will not be corrected.

利用SCADA量测补充PMU不可观测的区域，进行线性状态估计具体过程为：Using SCADA measurement to supplement the unobservable area of PMU, the specific process of linear state estimation is as follows:

使用上标O表示PMU量测可观测区域，上标U表示PMU量测不可观测区域，则节点电压方程可表示为：Use the superscript O to indicate the observable area measured by the PMU, and the superscript U to indicate the unobservable area measured by the PMU, then the node voltage equation can be expressed as:

$[\begin{matrix} {\overset{\cdot \cdot}{V V}}_{i i}^{O o} \\ {\overset{\cdot \cdot}{I I}}_{i i}^{O o} \\ {\overset{\cdot \cdot}{I I}}_{ij ij}^{O o} \\ {\overset{\cdot &Center Dot;}{V V}}_{i i}^{U u} \\ {\overset{\cdot &Center Dot;}{I I}}_{i i}^{U u} \end{matrix}] = = [\begin{matrix} E E. & 00 \\ {Y Y}_{i i}^{OO OO} & {Y Y}_{i i}^{OU ou} \\ {Y Y}_{ij ij}^{OO OO} & {Y Y}_{ij ij}^{OU ou} \\ 00 & E E. \\ {Y Y}_{i i}^{UO UO} & {Y Y}_{i i}^{UU UU} \end{matrix}] [\begin{matrix} {\overset{\cdot &Center Dot;}{V V}}_{i i}^{O o} \\ {\overset{\cdot &Center Dot;}{V V}}_{i i}^{U u} \end{matrix}] - - - - - - ((77))$

其中：和分别为可观测和不可观测区域的节点电压矩阵；和分别为可观测和不可观测区域的节点注入电流矩阵；E为单位矩阵；为节点注入可观自导纳矩阵，为节点注入可观与不可观互导纳矩阵，为节点注入不可观和可观互导纳矩阵，为节点注入不可观自导纳矩阵；为支路可观电流矩阵，为支路可观自导纳矩阵，为支路可观与不可观互导纳矩阵；in: and are the node voltage matrices of the observable and unobservable regions, respectively; and Inject current matrices into nodes in the observable and unobservable regions respectively; E is the identity matrix; Inject a considerable self-admittance matrix for the node, Inject observable and nonobservable transadmittance matrices for nodes, Inject unobservable and observable transadmittance matrices for nodes, Inject unobservable self-admittance matrix for nodes; is the considerable current matrix of the branch, is the branch observable self-admittance matrix, is the branch observable and non-observable mutual admittance matrix;

不可观测区域的节点注入电流矩阵表示为：Node injection current matrix in the unobservable region Expressed as:

${\overset{\cdot &Center Dot;}{I I}}_{i i}^{U u} = = \frac{{P P}_{i i} - - {jQ jQ}_{i i}}{{\overset{\cdot &Center Dot;}{V V}}_{i i}^{* * U u}} - - - - - - ((88))$

其中，P_i和Q_i为注入的有功和无功功率，为的共轭矩阵；where P _i and Q _i are the injected active and reactive power, for the conjugate matrix;

设节点等效注入可观导纳矩阵表示为：Assuming that the nodes are equivalently injected into an observable admittance matrix Expressed as:

${Y Y}_{i i}^{U u} = = \frac{{\overset{\cdot &Center Dot;}{I I}}_{i i}^{U u}}{{\overset{\cdot &Center Dot;}{V V}}_{i i}^{U u}} = = \frac{{P P}_{i i} - - {jQ jQ}_{i i}}{{| | {\overset{\cdot &Center Dot;}{V V}}_{i i}^{U u} | |}^{22}} - - - - - - ((99))$

将式（9）带入下式，有Substituting equation (9) into the following equation, we have

${\overset{\cdot &Center Dot;}{I I}}_{i i}^{U u} = = {Y Y}_{i i}^{U u} {\overset{\cdot \cdot}{V V}}_{i i}^{U u} = = {Y Y}_{i i}^{UO UO} {\overset{\cdot &Center Dot;}{V V}}_{i i}^{O o} + + {Y Y}_{i i}^{UU UU} {\overset{\cdot \cdot}{V V}}_{i i}^{U u} - - - - - - ((1010))$

整理得：Organized:

$00 = = {Y Y}_{i i}^{UO UO} {\overset{\cdot \cdot}{V V}}_{i i}^{O o} + + (({Y Y}_{i i}^{UU UU} - - {Y Y}_{i i}^{U u})) {\overset{\cdot &Center Dot;}{V V}}_{i i}^{U u} - - - - - - ((1111))$

变型后的节点电流方程为：The modified node current equation is:

$[\begin{matrix} {\overset{\cdot \cdot}{V V}}_{i i}^{O o} \\ {\overset{\cdot \cdot}{I I}}_{i i}^{O o} \\ {\overset{\cdot \cdot}{I I}}_{ij ij}^{O o} \\ {\overset{\cdot \cdot}{V V}}_{i i}^{U u} \\ 00 \end{matrix}] = = [\begin{matrix} E E. & 00 \\ {Y Y}_{i i}^{OO OO} & {Y Y}_{i i}^{OU ou} \\ {Y Y}_{ij ij}^{OO OO} & {Y Y}_{ij ij}^{OU ou} \\ 00 & E E. \\ {Y Y}_{i i}^{UO UO} & {Y Y}_{i i}^{UU UU} - - {Y Y}_{i i}^{U u} \end{matrix}] [\begin{matrix} {\overset{\cdot \cdot}{V V}}_{i i}^{O o} \\ {\overset{\cdot \cdot}{V V}}_{i i}^{U u} \end{matrix}] - - - - - - ((1212))$

把该节点电流方程作为线性计算的线性方程，带入式（3）进行线性状态估。Take this node current equation as a linear equation for linear calculation and bring it into formula (3) for linear state estimation.

进行非线性状态估计中，分别引入PMU电压量测信息和相角量测信息、PMU功率量测信息以及PMU电流量测信息进行非线性状态估计。In the nonlinear state estimation, PMU voltage measurement information and phase angle measurement information, PMU power measurement information and PMU current measurement information are respectively introduced to perform nonlinear state estimation.

引入PMU电压量测信息和相角量测信息进行非线性状态估计具体过程为：The specific process of introducing PMU voltage measurement information and phase angle measurement information for nonlinear state estimation is as follows:

1）直接将PMU节点电压相量量测方程加入到非线性状态估计中，PMU电压和相角量测方程为：1) The PMU node voltage phasor measurement equation is directly added to the nonlinear state estimation, and the PMU voltage and phase angle measurement equations are:

$\{\begin{matrix} {V V}_{i i}^{m m} = = {V V}_{i i} \\ {θ θ}_{i i}^{m m} = = {θ θ}_{i i} \end{matrix} - - - - - - ((1313))$

其中，和分别为节点i的PMU电压量测信息和相角量测信息，V_i和θ_i为节点i的电压和相角，对应的雅克比矩阵的元素为1，其他的元素均为0；in, and are the PMU voltage measurement information and phase angle measurement information of node i respectively, V _i and θ _i are the voltage and phase angle of node i, the elements of the corresponding Jacobian matrix are 1, and the other elements are 0;

2）引入功率相角差；2) Introduce power phase angle difference;

对于含有PMU相角量测的大电网非线性状态估计中，引入新量测量θ_ij，其中节点i与节点j之间的θ_ij＝θ_i-θ_j，θ_j为节点j的相角；则有For large power grid nonlinear state estimation with PMU phase angle measurement, a new quantity measurement θ _ij is introduced, where θ _ij = θ _i - θ j between node i and node _j , θ _j is the phase angle of node j; then there is

$\{\begin{matrix} \frac{{dθ dθ}_{ij ij}}{{dθ dθ}_{i i}} = = 11 \\ \frac{{dθ dθ}_{ij ij}}{{dθ dθ}_{j j}} = = - - 11 \end{matrix} - - - - - - ((1414)) . .$

引入PMU功率量测信息进行非线性状态估计具体过程为：The specific process of introducing PMU power measurement information for nonlinear state estimation is as follows:

$\{\begin{matrix} {P P}_{i i}^{m m} = = {P P}_{i i} \\ {Q Q}_{i i}^{m m} = = {Q Q}_{i i} \end{matrix} - - - - - - ((1515))$

其中，和分别为节点i的有功功率和无功功率量测信息，P_i和Q_i分别为节点i的有功功率和无功功率；PMU功率量测按节点注入功率和支路功率的类型，其对应的雅克比矩阵系数与SCADA量测功率量对应的系数一致。in, and are the active power and reactive power measurement information of node i respectively, P _i and Q _i are the active power and reactive power of node i respectively; PMU power measurement is based on the type of node injection power and branch power, and its corresponding The coefficients of the Jacobian matrix are consistent with those corresponding to the SCADA measurement power.

引入PMU电流量测信息进行非线性状态估计具体过程分为以下两种情况：The specific process of introducing PMU current measurement information for nonlinear state estimation is divided into the following two situations:

1）将电流量转化为支路潮流，有1) To convert the current into branch power flow, there is

$\{\begin{matrix} {P P}_{ij ij} = = {V V}_{i i} {I I}_{i i} cos cos (({θ θ}_{ui ui} - - {θ θ}_{Ii II})) \\ {Q Q}_{ij ij} = = {V V}_{i i} {I I}_{i i} sin sin (({θ θ}_{ui ui} - - {θ θ}_{Ii II})) \end{matrix} - - - - - - ((1616))$

其中，P_ij和Q_ij分别为节点i与节点j之间的支路ij的有功功率和无功功率，I_i为节点i的电流，和分别为节点i的电压相角和电流相角；P_ij和Q_ij的权值按照如下误差传递公式计算；Among them, P _ij and Q _ij are the active power and reactive power of branch ij between node i and node j respectively, I _i is the current of node i, and are the voltage phase angle and current phase angle of node i respectively; the weights of P _ij and Q _ij are calculated according to the following error transfer formula;

${R R}_{{P P}_{ij ij}} = = {((\frac{{&PartialD; &PartialD; P P}_{ij ij}}{{&PartialD; &PartialD; V V}_{i i}} {σ σ}_{{V V}_{i i}}))}^{22} + + {((\frac{{&PartialD; &PartialD; P P}_{ij ij}}{{&PartialD; &PartialD; I I}_{i i}} {σ σ}_{{I I}_{i i}}))}^{22} + + {((\frac{{&PartialD; &PartialD; P P}_{ij ij}}{{&PartialD; &PartialD; θ θ}_{Vi Vi}} {σ σ}_{{θ θ}_{Vi Vi}}))}^{22} + + {((\frac{{&PartialD; &PartialD; P P}_{ij ij}}{{&PartialD; &PartialD; θ θ}_{Ii II}} {σ σ}_{{θ θ}_{Ii II}}))}^{22} - - - - - - ((1717))$

${R R}_{{Q Q}_{ij ij}} = = {((\frac{{&PartialD; &PartialD; Q Q}_{ij ij}}{{&PartialD; &PartialD; V V}_{i i}} {σ σ}_{{V V}_{i i}}))}^{22} + + {((\frac{{&PartialD; &PartialD; Q Q}_{ij ij}}{{&PartialD; &PartialD; I I}_{i i}} {σ σ}_{{I I}_{i i}}))}^{22} + + {((\frac{{&PartialD; &PartialD; Q Q}_{ij ij}}{{&PartialD; &PartialD; θ θ}_{Vi Vi}} {σ σ}_{{θ θ}_{Vi Vi}}))}^{22} + + {((\frac{{&PartialD; &PartialD; Q Q}_{ij ij}}{{&PartialD; &PartialD; θ θ}_{Ii II}} {σ σ}_{{θ θ}_{Ii II}}))}^{22} - - - - - - ((1818))$

其中，和为等值有功量测和等值无功量测的误差方差，和为分别为电压幅值V_i、电流I_i、电压相角θ_ui和注入电流相角θ_Ii对应的标准差；P_ij和Q_ij的权值分别表示为 $R_{P_{ij}}^{- 1} = \frac{1}{R_{P_{ij}}}$ 和 $R_{Q_{ij}}^{- 1} = \frac{1}{R_{Q_{ij}}};$ in, and is the error variance of equivalent active power measurement and equivalent reactive power measurement, and are the standard deviations corresponding to voltage amplitude V _i , current I _i , voltage phase angle θ _ui and injection current phase angle θ _Ii respectively; the weights of P _ij and Q _ij are expressed as $R_{P_{ij}}^{- 1} = \frac{1}{R_{P_{ij}}}$ and $R_{Q_{ij}}^{- 1} = \frac{1}{R_{Q_{ij}}};$

将配置PMU节点的支路电流向量转化为相邻节点电压向量，有Transform the branch current vector of the configuration PMU node into the adjacent node voltage vector, there is

${\overset{\cdot &Center Dot;}{V V}}_{j j} = = \frac{{\overset{\cdot &Center Dot;}{I I}}_{ij ij} - - (({Y Y}_{i i 00} + + {Y Y}_{ij ij})) {\overset{\cdot &Center Dot;}{V V}}_{i i}}{- - {Y Y}_{ij ij}} - - - - - - ((1919))$

其中，为节点j的相电压，为支路ij的电流向量，Y_i0为节点i的对地电容，Y_ij为节点导纳矩阵的元素；的权值按照如下误差传递公式计算；in, is the phase voltage at node j, is the current vector of branch ij, Y _i0 is the ground capacitance of node i, and Y _ij is the element of node admittance matrix; The weight of is calculated according to the following error transfer formula;

${R R}_{{\overset{\cdot \cdot}{V V}}_{j j}} = = {((\frac{&PartialD; &PartialD; {\overset{\cdot &Center Dot;}{V V}}_{j j}}{{&PartialD; &PartialD; V V}_{i i}} {σ σ}_{{V V}_{i i}}))}^{22} + + {((\frac{&PartialD; &PartialD; {\overset{\cdot \cdot}{V V}}_{j j}}{{&PartialD; &PartialD; θ θ}_{i i}} {σ σ}_{{θ θ}_{i i}}))}^{22} + + {((\frac{&PartialD; &PartialD; {\overset{\cdot \cdot}{V V}}_{j j}}{{&PartialD; &PartialD; I I}_{ij ij}} {σ σ}_{{I I}_{ij ij}}))}^{22} + + {((\frac{&PartialD; &PartialD; {\overset{\cdot &Center Dot;}{V V}}_{j j}}{{&PartialD; &PartialD; θ θ}_{ij ij}^{I I}} {σ σ}_{{θ θ}_{ij ij}^{I I}}))}^{22} - - - - - - ((2020))$

其中，为等值电压向量量测的误差方差，和分别为电压幅值V_i、电压相角θ、支路电流I_ij和支路电流相角对应的标准差；的权值表示为 in, is the error variance of the equivalent voltage vector measurement, and Respectively, voltage amplitude V _i , voltage phase angle θ, branch current I _ij and branch current phase angle Corresponding standard deviation; The weight of is expressed as

2）构造伪量测量；2) Construct pseudo-quantity measurement;

构造伪量测量通过旋转-θ_i的角度，将的θ_i变量变为0，从而将支路ij的i端的角度固定住，同时构造出相角差θ_ij，利用θ_ij进行解耦，过程如下：Construct pseudo-quantity measurements By rotating the angle of _-θi , the The θ _i variable of becomes 0, so that the angle of the i-end of the branch ij is fixed, and the phase angle difference θ _ij is constructed at the same time, and the θ _ij is used for decoupling. The process is as follows:

$\begin{matrix} {\overset{\cdot &Center Dot;}{I I}}_{ij ij . . 00} = = {\overset{\cdot &Center Dot;}{I I}}_{ij ij} {e e}^{- - j j {θ θ}_{i i}} = = [[{y the y}_{ij ij} (({\overset{\cdot &Center Dot;}{V V}}_{i i} - - {\overset{\cdot &Center Dot;}{V V}}_{j j})) + + {y the y}_{i i 00} {\overset{\cdot &Center Dot;}{V V}}_{i i}]] {e e}^{- - j j {θ θ}_{i i}} = = {y the y}_{ij ij} (({V V}_{i i} - - {V V}_{j j} {e e}^{- - j j {θ θ}_{ij ij}})) + + {y the y}_{i i 00} {V V}_{i i} \\ = = ((g g + + jb jb)) [[{V V}_{i i} - - {V V}_{j j} ((cos cos {θ θ}_{ij ij} - - j j sin sin {θ θ}_{ij ij}))]] + + j j {y the y}_{ic ic} {V V}_{i i} \end{matrix} - - - - - - ((21 twenty one))$

其中，为构造的旋转伪量测量，y_ij为支路ij的导纳，y_i0为线路i端的对地导纳，y_ic为支路ij的对地容抗，g和b分别为支路ij的电导和电纳；in, is the constructed rotation pseudo-quantity measurement, y _ij is the admittance of branch ij, y _i0 is the ground admittance of line i end, y _ic is the ground capacitance of branch ij, g and b are the branch ij’s conductance and susceptance;

将分解为实部和虚部两个变量，有Will decompose into real part and imaginary part two variables, with

$\{\begin{matrix} {I I}_{ij ij . . 00}^{re re} = = g g {V V}_{i i} - - {gV wxya}_{j j} cos cos {θ θ}_{ij ij} - - {bV v}_{j j} sin sin {θ θ}_{ij ij} \\ {I I}_{ij ij . . 00}^{im im} = = {gV wxya}_{j j} sin sin {θ θ}_{ij ij} + + {bV v}_{i i} - - {bV v}_{j j} cos cos {θ θ}_{ij ij} + + {y the y}_{ic ic} {V V}_{i i} \end{matrix} - - - - - - ((22 twenty two))$

求偏导，有Seeking partial guidance, there is

$\{\begin{matrix} \frac{{&PartialD; &PartialD; I I}_{ij ij . . 00}^{re re}}{{&PartialD; &PartialD; θ θ}_{i i}} = = {gV wxya}_{j j} sin sin {θ θ}_{ij ij} - - {bV v}_{j j} cos cos {θ θ}_{ij ij} \\ \frac{{&PartialD; &PartialD; I I}_{ij ij . . 00}^{re re}}{{&PartialD; &PartialD; V V}_{i i}} = = g g \\ \frac{{&PartialD; &PartialD; I I}_{ij ij . . 00}^{im im}}{{&PartialD; &PartialD; θ θ}_{i i}} = = {gV wxya}_{j j} cos cos {θ θ}_{ij ij} + + {bV v}_{j j} sin sin {θ θ}_{ij ij} \\ \frac{{&PartialD; &PartialD; I I}_{ij ij . . 00}^{im im}}{{&PartialD; &PartialD; V V}_{i i}} = = b b + + {y the y}_{ic ic} \end{matrix} - - - - - - ((23 twenty three))$

$\{\begin{matrix} \frac{{&PartialD; &PartialD; I I}_{ij ij . . 00}^{re re}}{{&PartialD; &PartialD; θ θ}_{j j}} = = - - g g {V V}_{j j} sin sin {θ θ}_{ij ij} + + {bV v}_{j j} cos cos {θ θ}_{ij ij} \\ \frac{{&PartialD; &PartialD; I I}_{ij ij . . 00}^{re re}}{{&PartialD; &PartialD; V V}_{j j}} = = - - g g cos cos {θ θ}_{ij ij} - - b b {sin sin θ θ}_{ij ij} \\ \frac{{&PartialD; &PartialD; I I}_{ij ij . . 00}^{im im}}{{&PartialD; &PartialD; θ θ}_{j j}} = = - - g g {V V}_{j j} cos cos {θ θ}_{ij ij} + + {bV v}_{j j} sin sin {θ θ}_{ij ij} \\ \frac{{&PartialD; &PartialD; I I}_{ij ij . . 00}^{im im}}{{&PartialD; &PartialD; V V}_{j j}} = = g g sin sin {θ θ}_{ij ij} - - {b b cos cos θ θ}_{ij ij} \end{matrix} - - - - - - ((24 twenty four))$

对于高压输电系统，r为线路电阻，x为线路电抗，则有r<<x，V_i≈V_j＝V₀，其中V₀为基准电压，θ_ij接近于0，所以有g<<b，cosθ_ij≈1，sinθ_ij≈0，化简有gsinθ_ij<<bcosθ_ij，|gcosθ_ij±bsinθ_ij|<<|gsinθ_ij±bcosθ_ij；For a high-voltage transmission system, r is the line resistance, x is the line reactance, then r<<x, V _i ≈ V _j =V ₀ , where V ₀ is the reference voltage, and θ _ij is close to 0, so g<<b , cosθ _ij ≈1, sinθ _ij ≈0, the simplification has gsinθ _ij <<bcosθ _ij , |gcosθ _ij ±bsinθ _ij |<<|gsinθ _ij ±bcosθ _ij ;

对公式（20）和（21）进行化简，有Simplifying formulas (20) and (21), we have

$\{\begin{matrix} \frac{{&PartialD; &PartialD; I I}_{ij ij . . 00}^{re re}}{&PartialD; &PartialD; {θ θ}_{i i}} = = - - b b {V V}_{00} \\ \frac{{&PartialD; &PartialD; I I}_{ij ij . . 00}^{re re}}{{&PartialD; &PartialD; V V}_{i i}} = = 00 \\ \frac{{&PartialD; &PartialD; I I}_{ij ij . . 00}^{im im}}{{&PartialD; &PartialD; θ θ}_{i i}} = = 00 \\ \frac{{&PartialD; &PartialD; I I}_{ij ij . . 00}^{im im}}{{&PartialD; &PartialD; V V}_{i i}} = = b b + + {y the y}_{ic ic} \end{matrix} - - - - - - ((2525))$

$\{\begin{matrix} \frac{{&PartialD; &PartialD; I I}_{ij ij . . 00}^{re re}}{&PartialD; &PartialD; {θ θ}_{j j}} = = b b {V V}_{00} \\ \frac{{&PartialD; &PartialD; I I}_{ij ij . . 00}^{re re}}{{&PartialD; &PartialD; V V}_{j j}} = = 00 \\ \frac{{&PartialD; &PartialD; I I}_{ij ij . . 00}^{im im}}{{&PartialD; &PartialD; θ θ}_{i i}} = = 00 \\ \frac{{&PartialD; &PartialD; I I}_{ij ij . . 00}^{im im}}{{&PartialD; &PartialD; V V}_{i i}} = = - - b b \end{matrix} - - - - - - ((2626))$

旋转伪量测量实现解耦，有Rotation pseudo-quantity measurement realizes decoupling, with

$(\begin{matrix} Δ Δ {I I}_{ij ij . . 00}^{re re} \\ {ΔI ΔI}_{ij ij . . 00}^{im im} \end{matrix}) = = (\begin{matrix} - - {B B}^{' '} & 00 \\ 00 & {B B}^{' '' '} \end{matrix}) (\begin{matrix} {V V}_{00} Δθ Δθ \\ Δv Δv \end{matrix}) - - - - - - ((2727))$

其中，B'和B′′分别为V₀Δθ和Δv对应的系数矩阵，在网络拓扑和参数不变的情况下均为常数；Δθ和Δv分别为相角增量和电压增量。Among them, B' and B'' are the coefficient matrices corresponding to V ₀ Δθ and Δv, respectively, and they are constant when the network topology and parameters remain unchanged; Δθ and Δv are phase angle increments and voltage increments, respectively.

与现有技术相比，本发明的有益效果在于：Compared with prior art, the beneficial effect of the present invention is:

A.针对电网中不同PMU的配置比例进行分析，可根据PMU的可观性，灵活选择不同的线性或非线性算法。A. According to the analysis of the configuration ratio of different PMUs in the power grid, different linear or nonlinear algorithms can be flexibly selected according to the observability of the PMU.

B.线性估计不再进行一次完成，而是根据第一次估计的残差值，修正权重再进行一次估计，经过测试对估计精度有一定改善。B. The linear estimation is no longer completed once, but based on the residual value of the first estimate, the weight is corrected and then estimated again. After testing, the estimation accuracy has been improved to a certain extent.

C.直接引入电压幅值和相角作为量测量，并赋予较大的权值参与估计，只要稍加改进，即可以直接应用于现有的快速分解状态估计程序，当PMU电压量测较精确时，可以显著改善估计效果。C. Directly introduce the voltage amplitude and phase angle as the quantity measurement, and give a larger weight to participate in the estimation. As long as a little improvement is made, it can be directly applied to the existing fast decomposition state estimation program. When the PMU voltage measurement is more accurate can significantly improve the estimation performance.

D.引入电压相角差作为量测量，主要约束节点间的相角差的作用，雅克比矩阵计算简单。可以消除由于PMU和SCADA选取平衡节点选取不同而重新归算或者由于PMU量测设备的由于共模因素引起的电压相角误差。D. Introducing the voltage phase angle difference as a quantity measurement mainly constrains the role of the phase angle difference between nodes, and the calculation of the Jacobian matrix is simple. It can eliminate the voltage phase angle error caused by the recalculation due to the difference in selection of the balance node between the PMU and the SCADA or the common mode factor of the PMU measurement equipment.

E.直接引入功率量测，可以直接用于快速分解的状态估计算法，直接增加量测量，提高冗余度，改善估计精度。E. Directly introduce power measurement, which can be directly used in the fast decomposition state estimation algorithm, directly increase the quantity measurement, increase the redundancy, and improve the estimation accuracy.

F.使用旋转法引入电流量作为伪量测量参与估计，旋转角仅选取电压相角作为初值参与迭代；精度与电压相角无关，仅与原有的电流和电流相角量测精度有关，传递误差小。可实现PQ解耦，解耦条件与传统状态估计一致，可以与传统的快速分解状态估计融合，实现快速计算。F. Use the rotation method to introduce the current quantity as a pseudo-quantity measurement to participate in the estimation. The rotation angle only selects the voltage phase angle as the initial value to participate in the iteration; the accuracy has nothing to do with the voltage phase angle, only related to the original current and current phase angle measurement accuracy, The transmission error is small. It can realize PQ decoupling, and the decoupling conditions are consistent with the traditional state estimation, and can be integrated with the traditional fast decomposition state estimation to realize fast calculation.

附图说明Description of drawings

图1是引入PMU量测信息的大电网状态估计方法流程图；Fig. 1 is a flow chart of a large power grid state estimation method that introduces PMU measurement information;

图2是含伪量测快速分解状态估计程序框图。Fig. 2 is a program block diagram of rapid decomposition state estimation with pseudo-measurements.

具体实施方式detailed description

下面结合附图对本发明作进一步详细说明。The present invention will be described in further detail below in conjunction with the accompanying drawings.

本发明提供一种引入PMU(PhasorMeasurementUnit，同步相量测量单元)量测信息的大电网状态估计方法，电力系统状态估计是利用实时量测系统的冗余度来提高数据精度，自动排除随机干扰所引起的错误信息，估计或预报系统的运行状态。The present invention provides a large power grid state estimation method that introduces PMU (PhasorMeasurementUnit, synchronized phasor measurement unit) measurement information. The power system state estimation uses the redundancy of the real-time measurement system to improve data accuracy and automatically eliminate random interference. Error information caused by estimating or predicting the operating state of the system.

充分利用了PMU量测特点和优点，在PMU量测完全可观测和不可观测两种情况下PMU量测信息参与状态估计的方法，使当前电网中PMU量测充分发挥在状态估计中的作用，提高状态估计精度，提高状态估计软件在目前实际电网以及未来大电网的实用化水平。Make full use of the characteristics and advantages of PMU measurement, the method of PMU measurement information participating in state estimation in the two cases of PMU measurement is completely observable and unobservable, so that the PMU measurement in the current power grid can fully play the role in state estimation, Improve the accuracy of state estimation and improve the practical level of state estimation software in the current actual power grid and the future large power grid.

该方法能够根据系统的可观性，在系统PMU量测可观测的情况下，完全利用PMU量测信息进行线性估计，或者系统大量装配PMU量测，仅部分节点不可观的时候，可以利用SCADA（SupervisoryControlAndDataAcquisition，数据采集与监视控制系统）量测补充，进行线性估计。本发明的线性估计模型考虑到了对地支路的电导。由于线性估计不需要进行迭代，因此估计所用的模型的精确度要高。若不考虑对地支路电导会对估计结果产生一定的影响。According to the observability of the system, when the PMU measurement of the system is observable, the PMU measurement information can be used for linear estimation, or when the system is equipped with a large number of PMU measurements and only some nodes are not observable, SCADA can be used ( SupervisoryControlAndDataAcquisition, data acquisition and monitoring control system) measurement supplement, linear estimation. The linear estimation model of the present invention takes into account the conductance of the branch to ground. Since linear estimators do not require iteration, the models used for estimation are more accurate. If the conductance of the ground branch is not considered, it will have a certain impact on the estimation results.

在不可观情况下，在PQ分解法基础上引入PUM的量测的状态估计。PQ分解法具有模型简单，计算速度快等优点。针对直接引入PMU电流量测存在的难题，本发明创新使用了旋转伪量测法，对电流向量进行旋转转化，从而达到引入电流量的目的，增加了估计冗余度，提高了估计精度。旋转伪量测法计算简单，可以与PQ分解法融合一起进行计算，引入的量测传递误差较小，具有实用价值。In the case of unobservable conditions, the PUM measurement state estimation is introduced on the basis of the PQ decomposition method. The PQ decomposition method has the advantages of simple model and fast calculation speed. Aiming at the problem of direct introduction of PMU current measurement, the invention innovatively uses the rotation pseudo-measurement method to rotate and transform the current vector, thereby achieving the purpose of introducing current, increasing estimation redundancy, and improving estimation accuracy. The calculation of the rotation pseudo-measurement method is simple, and it can be combined with the PQ decomposition method for calculation, and the measurement transfer error introduced is small, which has practical value.

1）SCADA：SupervisoryControlAndDataAcquisition系统，即数据采集与监视控制系统。是EMS的最重要的子系统，有着信息完整、提高效率、正确掌握系统运行状态、加快决策、能帮助快速诊断出系统故障状态等优势，现已经成为电力调度不可缺少的工具。1) SCADA: SupervisoryControlAndDataAcquisition system, that is, data acquisition and monitoring control system. It is the most important subsystem of EMS. It has the advantages of complete information, improved efficiency, correct control of system operating status, faster decision-making, and quick diagnosis of system fault status. It has become an indispensable tool for power dispatching.

2）PMU量测：同步相角测量单元。可以测量电网节点电压向量、功率和支路电流向量。数据测量精度高，采集和传输速度快。2) PMU measurement: Synchronous phase angle measurement unit. Grid node voltage vectors, power and branch current vectors can be measured. The data measurement accuracy is high, and the collection and transmission speed is fast.

3）可观测性：在电力系统计算中，如果利用已有的量测信息，可以计算出所有节点的电压幅值和相角量，这样就可以说系统状态是完全可观测的了。3) Observability: In the power system calculation, if the existing measurement information is used, the voltage amplitude and phase angle of all nodes can be calculated, so it can be said that the system state is completely observable.

4）代数可观性：对于一个节点数为n、测量向量维数为m的电力系统，如果系统线性量测模型的秩rank(H)=2n-1，即H满秩，则可认为系统是代数可观的。4) Algebraic observability: For a power system with n nodes and m measurement vector dimension, if the rank of the linear measurement model of the system is rank(H)=2n-1, that is, H is full rank, the system can be considered as Algebraically impressive.

5）状态估计：也成为滤波，利用实时量测系统的冗余度来提高数据精度，自动排除干扰所引起的错误信息，估计或预报系统的运行状态。5) State estimation: also known as filtering, using the redundancy of the real-time measurement system to improve data accuracy, automatically eliminate error information caused by interference, and estimate or forecast the operating state of the system.

6）PQ分解状态估计：以最小二乘法为基础，吸收潮流计算经验（PQ分解法）而建立状态估计算法。6) PQ decomposition state estimation: Based on the least square method, absorb the power flow calculation experience (PQ decomposition method) to establish a state estimation algorithm.

7）旋转伪量测法：利用已有的量测向量，旋转一定的角度，作为一个伪量测信息，参与状态估计计算的方法。7) Rotation pseudo-measurement method: use the existing measurement vector to rotate a certain angle, as a pseudo-measurement information, to participate in the method of state estimation calculation.

如图1，本发明提供一种引入PMU量测信息的大电网状态估计方法，所述方法包括以下步骤：As shown in Figure 1, the present invention provides a method for estimating the state of a large power grid that introduces PMU measurement information, and the method includes the following steps:

PMU量测与SCADA量测的最大区别是，它可以采集到电压的相角量测和电流的相角量测，如果在系统全部节点上都装上PMU装置，采集全部节点的电压幅值和相角量测，那么系统就是完全可观测的了。但这是不现实也不经济的做法，其实只需在部分节点上装设PMU就够了，因为装设PMU的节点不仅采集了节点的电压幅值和相角量测，而且还采集了该节点的注入电流幅值和相角量测、与该节点相连的支路电流幅值和相角量测，由该节点的电压、电流的幅值和相角量测可以得到相连节点的电压幅值和相角，所以每个节点上装设的PMU设备可以提供多个量测，当系统装设的全部PMU提供的量测能够算出系统的全部状态变量时，这个系统就达到了完全可观测的PMU配置水平，此时并不需要为每个节点都配置PMU。The biggest difference between PMU measurement and SCADA measurement is that it can collect the phase angle measurement of voltage and current. If PMU devices are installed on all nodes of the system, the voltage amplitude and phase angle measurement, then the system is fully observable. But this is unrealistic and economical. In fact, it is enough to install PMUs on some nodes, because the nodes where PMUs are installed not only collect the voltage amplitude and phase angle measurements of the nodes, but also collect the The injection current amplitude and phase angle measurement, the branch current amplitude and phase angle measurement connected to this node, the voltage amplitude of the connected node can be obtained from the voltage, current amplitude and phase angle measurement of this node and phase angle, so the PMU equipment installed on each node can provide multiple measurements. When the measurements provided by all the PMUs installed in the system can calculate all the state variables of the system, the system has reached a fully observable PMU At the configuration level, it is not necessary to configure a PMU for each node at this time.

文献上线性估计不需要进行迭代计算，可以直接求出结果。若量测数据中存在着较大坏数据，对估计的精确度影响很大。本方法在第一次估计完以后，计算估计值与量测值的最大残差，若残差超过一定的值，将最大残差对应的量测降低其权重，然后再进行一次线性状态估计，相当于再经行一次迭代计算。本方法可以多次使用。In the literature, linear estimation does not require iterative calculations, and the results can be obtained directly. If there are large bad data in the measurement data, it will have a great impact on the accuracy of the estimation. In this method, after the first estimation, the maximum residual error between the estimated value and the measured value is calculated. If the residual error exceeds a certain value, the weight of the measurement corresponding to the maximum residual error is reduced, and then a linear state estimation is performed again. It is equivalent to performing an iterative calculation again. This method can be used multiple times.

一般的线性估计可以通过收敛条件对精度进行控制，可以采用忽略对地电导的模型计算。而基于PMU的线性估计不需要进行迭代，直接计算出来。因此对模型的精度要求较高，需要考虑等效后的变压器支路对地点电导。若不考虑对地电导，可能会对变压器支路两端的状态量估计产生较大影响。因此，步骤3中根据PMU量测信息的可观性进行大电网的状态估计分为以下情况：The general linear estimation can control the accuracy through the convergence condition, and can be calculated by a model that ignores the conductance to the ground. The PMU-based linear estimation does not need to be iterated, but is directly calculated. Therefore, the accuracy of the model is required to be high, and the conductance of the equivalent transformer branch to the site needs to be considered. If the conductance to ground is not considered, it may have a great impact on the state quantity estimation at both ends of the transformer branch. Therefore, in step 3, the state estimation of the large power grid based on the observability of PMU measurement information is divided into the following situations:

z＝h(x)+v＝Ax+v（1）z=h(x)+v=Ax+v(1)

目标函数表示为：The objective function is expressed as:

J(x)＝[z-Ax]^TR^-1[z-Ax]（2）J(x)＝[z-Ax] ^T R ^-1 [z-Ax] (2)

其中，为残差，表示为：in, is the residual, expressed as:

PMU设备装备系统将是一个渐进的过程，因此，在相当长的一段时间内，PMU量测对系统还将是不完全可观测的，在这种情况下就需要利用SCADA量测补充PMU不可观测的区域，进行线性状态估计具体过程为：PMU equipment equipment system will be a gradual process, therefore, for a long period of time, PMU measurement will not be completely observable to the system, in this case, it is necessary to use SCADA measurement to supplement PMU unobservable In the region, the specific process of linear state estimation is as follows:

$[\begin{matrix} {\overset{\cdot &Center Dot;}{V V}}_{i i}^{O o} \\ {\overset{\cdot &Center Dot;}{I I}}_{i i}^{O o} \\ {\overset{\cdot &Center Dot;}{I I}}_{ij ij}^{O o} \\ {\overset{\cdot &Center Dot;}{V V}}_{i i}^{U u} \\ {\overset{\cdot &Center Dot;}{I I}}_{i i}^{U u} \end{matrix}] = = [\begin{matrix} E E. & 00 \\ {Y Y}_{i i}^{OO OO} & {Y Y}_{i i}^{OU ou} \\ {Y Y}_{ij ij}^{OO OO} & {Y Y}_{ij ij}^{OU ou} \\ 00 & E E. \\ {Y Y}_{i i}^{UO UO} & {Y Y}_{i i}^{UU UU} \end{matrix}] [\begin{matrix} {\overset{\cdot &Center Dot;}{V V}}_{i i}^{O o} \\ {\overset{\cdot &Center Dot;}{V V}}_{i i}^{U u} \end{matrix}] - - - - - - ((77))$

其中：和分别为可观测和不可观测区域的节点电压矩阵；和分别为可观测和不可观测区域的节点注入电流矩阵；E为单位矩阵；为节点注入可观自导纳矩阵，为节点注入可观与不可观互导纳矩阵，节点注入不可观和可观互导纳矩阵，为节点注入不可观自导纳矩阵；为支路可观电流矩阵，为支路可观自导纳矩阵，为支路可观与不可观互导纳矩阵；in: and are the node voltage matrices of the observable and unobservable regions, respectively; and Inject current matrices into nodes in the observable and unobservable regions respectively; E is the identity matrix; Inject a considerable self-admittance matrix for the node, Inject observable and nonobservable transadmittance matrices for nodes, The nodes inject unobservable and observable transadmittance matrices, Inject unobservable self-admittance matrix for nodes; is the considerable current matrix of the branch, is the branch observable self-admittance matrix, is the branch observable and non-observable mutual admittance matrix;

对不可观测区域只采用了节点电压和节点注入电流的理由：Reasons for only adopting node voltage and node injection current for the unobservable region:

1）节点的注入量是决定系统状态的因变量，而支路电流（或功率）只是描述系统状态的从变量，采用节点电压和节点注入电流已完全可以描述不可观测区域的状态了；1) The injection amount of the node is the dependent variable that determines the state of the system, while the branch current (or power) is only a dependent variable that describes the state of the system, and the state of the unobservable area can be completely described by using the node voltage and node injection current;

2）不可观测区域的节点电压和节点注入电流可以方便的由状态估计结果得到；2) The node voltage and node injection current in the unobservable area can be easily obtained from the state estimation results;

3）对PMU不可观测区域补偿节点电压和节点注入电流量测后，已达到对系统的完全可观测性；3) After measuring the compensation node voltage and node injection current in the unobservable area of the PMU, the complete observability of the system has been achieved;

这里要用到节点电压的实部和虚部，而电压的实部和虚部要由电压的幅值和相角求出。The real and imaginary parts of the node voltage are used here, and the real and imaginary parts of the voltage are obtained from the amplitude and phase angle of the voltage.

如果对不可观测区域使用SCADA量测则得不到电压相角，也就无法求出节点注入电流，本文对节点电流公式进行变型以便利用SCADA量测。If SCADA is used to measure the unobservable area, the voltage phase angle cannot be obtained, and the node injection current cannot be obtained. This paper modifies the node current formula to use SCADA measurement.

${\overset{\cdot &Center Dot;}{I I}}_{i i}^{U u} = = {Y Y}_{i i}^{U u} {\overset{\cdot &Center Dot;}{V V}}_{i i}^{U u} = = {Y Y}_{i i}^{UO UO} {\overset{\cdot &Center Dot;}{V V}}_{i i}^{O o} + + {Y Y}_{i i}^{UU UU} {\overset{\cdot &Center Dot;}{V V}}_{i i}^{U u} - - - - - - ((1010))$

整理得：Organized:

$00 = = {Y Y}_{i i}^{UO UO} {\overset{\cdot &Center Dot;}{V V}}_{i i}^{O o} + + (({Y Y}_{i i}^{UU UU} - - {Y Y}_{i i}^{U u})) {\overset{\cdot &Center Dot;}{V V}}_{i i}^{U u} - - - - - - ((1111))$

变型后的节点电流方程为：The modified node current equation is:

$[\begin{matrix} {\overset{\cdot &Center Dot;}{V V}}_{i i}^{O o} \\ {\overset{\cdot &Center Dot;}{I I}}_{i i}^{O o} \\ {\overset{\cdot &Center Dot;}{I I}}_{ij ij}^{O o} \\ {\overset{\cdot &Center Dot;}{V V}}_{i i}^{U u} \\ 00 \end{matrix}] = = [\begin{matrix} E E. & 00 \\ {Y Y}_{i i}^{OO OO} & {Y Y}_{i i}^{OU ou} \\ {Y Y}_{ij ij}^{OO OO} & {Y Y}_{ij ij}^{OU ou} \\ 00 & E E. \\ {Y Y}_{i i}^{UO UO} & {Y Y}_{i i}^{UU UU} - - {Y Y}_{i i}^{U u} \end{matrix}] [\begin{matrix} {\overset{\cdot &Center Dot;}{V V}}_{i i}^{O o} \\ {\overset{\cdot &Center Dot;}{V V}}_{i i}^{U u} \end{matrix}] - - - - - - ((1212))$

其中，和分别为节点i的PMU电压量测信息和相角量测信息，V_i和θ_i为节点i的电压和相角，对应的雅克比矩阵的元素为1，其他的元素均为0；这种模型与传统状态估计模型中母线电压幅值测量值的用法完全相同，当在某条母线配置PMU时，量测方程中增加了上述2个方程以后，量测雅可比矩阵增加2行，且每行只有一个取值为1的非零元素。in, and are the PMU voltage measurement information and phase angle measurement information of node i respectively, V _i and θ _i are the voltage and phase angle of node i, the elements of the corresponding Jacobian matrix are 1, and the other elements are 0; The usage of the model is exactly the same as that of the bus voltage amplitude measurement value in the traditional state estimation model. When a PMU is configured on a bus, after the above two equations are added to the measurement equation, the measurement Jacobian matrix is added by 2 rows, and each A row has only one non-zero element with value 1.

2）引入功率相角差；2) Introduce power phase angle difference;

这种对雅可比矩阵的修改非常简单，可以直接用于状态估计中。采用相角差的方法时，将不存在参考点的问题，直接量测(或计算)相角差都不依靠参考点。由于θ_ij为节点之间的相对相角差，可以消除由于PMU和SCADA选取平衡节点选取不同，重新归算产生的误差，还可以消除PMU量测设备的由于共模因素引起的电压相角误差。θ_ij主要约束节点间的相角差的作用。This modification of the Jacobian is very simple and can be used directly in state estimation. When the phase angle difference method is adopted, there will be no reference point problem, and the direct measurement (or calculation) of the phase angle difference does not depend on the reference point. Since θ _ij is the relative phase angle difference between the nodes, it can eliminate the error caused by the recalculation due to the different selection of balance nodes between the PMU and SCADA, and can also eliminate the voltage phase angle error caused by the common mode factor of the PMU measurement equipment . _θij mainly constrains the effect of the phase angle difference between nodes.

以上两种方法中，对于归算误差或共模误差较小的PMU相角量测，可以直接用方法1），对于误差较大的相角量测，使用方法2）。Among the above two methods, method 1) can be directly used for PMU phase angle measurement with small reduction error or common mode error, and method 2) for phase angle measurement with large error.

直接引入支路存在困难，原因在于各支路电流是电压相角θ_i和θ_j的函数，电流向量随着各个节点电压的相角变化而变化，一般情况下，各个节点相角θ_i和θ_j不能简单地考虑为0，无法用PQ解耦计算，给计算带来了困难。direct access branch Difficulty exists because each branch current is a function of voltage phase angles θ _i and θ _j , and the current vector changes with the phase angle of each node voltage. In general, each node phase angle θ _i and θ _j cannot be simply considered as 0, and cannot be solved by PQ Coupled calculations bring difficulties to calculations.

1）将电流量转化为支路潮流，有1) Convert the current amount into branch power flow, there is

其中，P_ij和Q_ij分别为节点i与节点j之间的支路ij的有功功率和无功功率，I_i为节点i的电流，θ_ui和θ_Ii分别为节点i的电压相角和电流相角；P_ij和Q_ij的权值按照如下误差传递公式计算；Among them, P _ij and Q _ij are the active power and reactive power of branch ij between node i and node j respectively, I _i is the current of node i, θ _ui and θ _Ii are the voltage phase angle and Current phase angle; the weights of P _ij and Q _ij are calculated according to the following error transfer formula;

${\overset{\cdot \cdot}{V V}}_{j j} = = \frac{{\overset{\cdot \cdot}{I I}}_{ij ij} - - (({Y Y}_{i i 00} + + {Y Y}_{ij ij})) {\overset{\cdot \cdot}{V V}}_{i i}}{- - {Y Y}_{ij ij}} - - - - - - ((1919))$

${R R}_{{\overset{\cdot \cdot}{V V}}_{j j}} = = {((\frac{&PartialD; &PartialD; {\overset{\cdot \cdot}{V V}}_{j j}}{{&PartialD; &PartialD; V V}_{i i}} {σ σ}_{{V V}_{i i}}))}^{22} + + {((\frac{&PartialD; &PartialD; {\overset{\cdot \cdot}{V V}}_{j j}}{{&PartialD; &PartialD; θ θ}_{i i}} {σ σ}_{{θ θ}_{i i}}))}^{22} + + {((\frac{&PartialD; &PartialD; {\overset{\cdot &Center Dot;}{V V}}_{j j}}{{&PartialD; &PartialD; I I}_{ij ij}} {σ σ}_{{I I}_{ij ij}}))}^{22} + + {((\frac{&PartialD; &PartialD; {\overset{\cdot \cdot}{V V}}_{j j}}{{&PartialD; &PartialD; θ θ}_{ij ij}^{I I}} {σ σ}_{{θ θ}_{ij ij}^{I I}}))}^{22} - - - - - - ((2020))$

2）构造伪量测量；2) Construct pseudo-quantity measurement;

如图2，构造伪量测量通过旋转-θ_i的角度，将的θ_i变量变为0，从而将支路ij的i端的角度固定住，同时构造出相角差θ_ij，利用θ_ij进行解耦，过程如下：As shown in Figure 2, construct a pseudo-quantity measurement By rotating the angle of _-θi , the The θ _i variable of becomes 0, so that the angle of the i-end of the branch ij is fixed, and the phase angle difference θ _ij is constructed at the same time, and the θ _ij is used for decoupling. The process is as follows:

$\begin{matrix} {\overset{\cdot &Center Dot;}{I I}}_{ij ij . . 00} = = {\overset{\cdot &Center Dot;}{I I}}_{ij ij} {e e}^{- - j j {θ θ}_{i i}} = = [[{y the y}_{ij ij} (({\overset{\cdot &Center Dot;}{V V}}_{i i} - - {\overset{\cdot \cdot}{V V}}_{j j})) + + {y the y}_{i i 00} {\overset{\cdot &Center Dot;}{V V}}_{i i}]] {e e}^{- - j j {θ θ}_{i i}} = = {y the y}_{ij ij} (({V V}_{i i} - - {V V}_{j j} {e e}^{- - j j {θ θ}_{ij ij}})) + + {y the y}_{i i 00} {V V}_{i i} \\ = = ((g g + + jb jb)) [[{V V}_{i i} - - {V V}_{j j} ((cos cos {θ θ}_{ij ij} - - j j sin sin {θ θ}_{ij ij}))]] + + j j {y the y}_{ic ic} {V V}_{i i} \end{matrix} - - - - - - ((21 twenty one))$

求偏导，有Seeking partial guidance, there is

因此，这种方法可以和传统状态估计PQ分解法一起进行迭代计算。Therefore, this method can be iteratively calculated together with the traditional state estimation PQ decomposition method.

迭代时，若PMU的电压相角足够精确，伪量测量的相角可以若不够精确，则前几次迭代旋转相角取以后的每一次迭代，取最新的状态量这样伪量测量每一次迭代都会变化（只是旋转的角度不同），计算量较小。When iterating, if the voltage phase angle of the PMU Accurate enough for pseudo-quantity measurements The phase angle can be like is not accurate enough, the rotation phase angle of the first few iterations is taken as For each subsequent iteration, the latest state quantity is taken Such a pseudo-quantity measurement Each iteration will change (only the angle of rotation is different), and the amount of calculation is small.

以上两种引入电流量测的方法中，当电压幅值和相角量测均有一定误差时，选择方法②，计算较为准确；当电压幅值量测准确，电压相角量测误差较大时，选择方法①，程序编制较简单。Among the above two methods of introducing current measurement, when the voltage amplitude and phase angle measurement have certain errors, choose method ②, and the calculation is more accurate; when the voltage amplitude measurement is accurate, the voltage phase angle measurement error is large When the method ① is selected, the programming is relatively simple.

含PMU的状态估计方法提供了电力系统含PMU量测的状态估计方案。电力系统状态估计是利用实时量测系统的冗余度来提高数据精度，自动排除随机干扰所引起的错误信息，估计或预报系统的运行状态。该方案能够根据系统的可观性，在系统PMU可观的情况下，提出直接利用PMU的线性估计；在不可观情况下，在传统的状态估计方法上引入PUM的量测的状态估计，提高估计的冗余度，从而提高状态估计的精度。The state estimation method with PMU provides a state estimation scheme for power system with PMU measurement. Power system state estimation uses the redundancy of the real-time measurement system to improve data accuracy, automatically eliminates error information caused by random disturbances, and estimates or forecasts the operating state of the system. According to the observability of the system, the scheme can directly use the linear estimation of PMU when the system PMU is observable; in the case of unobservable situation, the state estimation of PUM measurement is introduced on the traditional state estimation method to improve the estimation. Redundancy, thereby improving the accuracy of state estimation.

最后应当说明的是：以上实施例仅用以说明本发明的技术方案而非对其限制，尽管参照上述实施例对本发明进行了详细的说明，所属领域的普通技术人员应当理解：依然可以对本发明的具体实施方式进行修改或者等同替换，而未脱离本发明精神和范围的任何修改或者等同替换，其均应涵盖在本发明的权利要求范围当中。Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: the present invention can still be Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention shall be covered by the scope of the claims of the present invention.

Claims

1. A large power grid state estimation method introducing PMU measurement information is characterized in that: the method comprises the following steps:

step 1: judging the algebraic observability of the power system;

step 2: judging the observability of PMU measurement information;

and step 3: carrying out state estimation on the large power grid;

in step 3, the state estimation of the large power grid according to the observability of the PMU measurement information is divided into the following cases:

A. if the PMU measurement information is completely observable, linear state estimation is carried out by adopting a rectangular coordinate linear model;

B. if the PMU measurement information is considerable, the SCADA measurement is used for supplementing the region which is not observable by the PMU, and the linear state estimation is carried out;

C. if the PMU measurement information is a little and considerable, carrying out nonlinear state estimation;

D. the PMU measurement information is not observable at all, and the linear estimation introduced into the PMU is not needed;

the specific process of linear state estimation by adopting the rectangular coordinate linear model comprises the following steps:

the real part and the imaginary part of the voltage are used as state quantities, the real part and the imaginary part of the node voltage, the node injection current and the branch current are used as quantity quantities, and then a measurement equation is expressed by a linear equation as follows:

z＝h(x)+v＝Ax+v(1)

wherein z is a measured quantity, x is a state quantity, v is a random error, A is a first order coefficient matrix, h (x) is a calculated value based on the measurement of the state quantity x, and there areh(x)＝Ax；

The objective function is expressed as:

J(x)＝[z-Ax]^TR^-1[z-Ax](2)

wherein R is^-1Is a weight matrix, J (x) is a least squares objective function;

the linear state estimation equation is:

{\hat{x}}^{(n + 1)} = {[A^{T} R^{- 1 (n)} A]}^{T} R^{- 1 (n)} z - - - (3)

wherein R is^-1(n)For the weight matrix calculated for the nth time,the estimated value calculated for the (n + 1) th time;

calculating the deviation of the residualComprises the following steps:

r_{\max}^{(n + 1)} = m a x {r ({\hat{x}}^{(n + 1)})} - - - (4)

wherein,is a residual, expressed as:

r ({\hat{x}}^{(n + 1)}) = z - h ({\hat{x}}^{(n + 1)}) - - - (5)

wherein,in order to estimate the value according to the state n +1 times,obtaining a measurement calculation value;

because the estimation accuracy of the power system state is greatly influenced by the current measurement accuracy and is less influenced by the voltage measurement, only the residual error with the maximum current is calculated, and the weight of the current measurement is corrected, including

R^{- 1 (n + 1)} = R_{c o r}^{- 1 (n)} - - - (6)

Wherein,the modified weight matrix corresponding to the maximum residual value is measured, and linear estimation is performed again until the maximum residual value is satisfiedAnd isWhereinIn order to correct the amount of the voltage correction,the amount of phase angle correction,_vand_θis a convergence threshold value preset according to the precision; if a measurement has been corrected, the measurement weight is not corrected.

2. The method of claim 1, wherein the method comprises the steps of: in step 1, for a power system with n nodes and m measurement vector dimensions, if the rank (H) of the linear measurement model coefficient matrix of the power system is 2n-1, that is, H full rank, the power system is considered to be algebraically considerable.

3. The method of claim 2, wherein the method comprises the steps of: in the step 2, the observability of PMU measurement information is judged according to the algebraic observability of the power system; the following cases are divided:

A. if rank (H) is satisfied, 2n-1, PMU measurement information is completely considerable;

B. if rank (H) is not less than a (2n-1), the PMU measurement information is considerable, wherein a is 0.95-0.9;

C. if rank (H) < a (2n-1) is satisfied, PMU measurement information is small and considerable;

D. if rank (h) is satisfied, it indicates that PMU measurement information is not observable at all.

4. The method of claim 1, wherein the method comprises the steps of: the specific process of utilizing SCADA measurement to supplement the non-observable region of PMU and carrying out linear state estimation comprises the following steps:

using superscript O to represent the observed region for PMU measurements and superscript U to represent the unobservable region for PMU measurements, the node voltage equation can be expressed as:

[\begin{matrix} {\overset{\cdot}{V}}_{i}^{O} \\ {\overset{\cdot}{I}}_{i}^{O} \\ {\overset{\cdot}{I}}_{i j}^{O} \\ {\overset{\cdot}{V}}_{i}^{U} \\ {\overset{\cdot}{I}}_{i}^{U} \end{matrix}] = [\begin{matrix} E & 0 \\ Y_{i}^{O O} & Y_{i}^{O U} \\ Y_{i j}^{O O} & Y_{i j}^{O U} \\ 0 & E \\ Y_{i}^{U O} & Y_{i}^{U U} \end{matrix}] [\begin{matrix} {\overset{\cdot}{V}}_{i}^{O} \\ {\overset{\cdot}{V}}_{i}^{U} \end{matrix}] - - - (7)

wherein:andnode voltage matrixes of observable and unobservable areas respectively;andinjecting current matrixes into nodes of observable and unobservable areas respectively; e is an identity matrix;a observable self-admittance matrix is injected for the node,the nodes are injected with observable and unobservable transadmittance matrices,injecting an unvisible and a viewable transadmittance matrix into the node,injecting an unobservable self-admittance matrix for the node;the current matrix can be observed by the branch circuit,the self-admittance matrix is observable for the branch,is a branch observable and unobservable transadmittance matrix;

node injection current matrix of non-observable regionExpressed as:

{\overset{\cdot}{I}}_{i}^{U} = \frac{P_{i} - {jQ}_{i}}{{\overset{\cdot}{V}}_{i}^{* U}} - - - (8)

wherein, P_iAnd Q_iFor the active and reactive power to be injected,is composed ofA conjugate matrix of (a);

node-based equivalent injection admittance matrixExpressed as:

Y_{i}^{U} = \frac{{\overset{\cdot}{I}}_{i}^{U}}{{\overset{\cdot}{V}}_{i}^{U}} = \frac{P_{i} - {jQ}_{i}}{{| {\overset{\cdot}{V}}_{i}^{U} |}^{2}} - - - (9)

bringing formula (9) into the following formula

{\overset{\cdot}{I}}_{i}^{U} = Y_{i}^{U} {\overset{\cdot}{V}}_{i}^{U} = Y_{i}^{U O} {\overset{\cdot}{V}}_{i}^{O} + Y_{i}^{U U} {\overset{\cdot}{V}}_{i}^{U} - - - (10)

Finishing to obtain:

0 = Y_{i}^{U O} {\overset{\cdot}{V}}_{i}^{O} + (Y_{i}^{U U} - Y_{i}^{U}) {\overset{\cdot}{V}}_{i}^{U} - - - (11)

the modified node current equation is:

[\begin{matrix} {\overset{\cdot}{V}}_{i}^{O} \\ {\overset{\cdot}{I}}_{i}^{O} \\ {\overset{\cdot}{I}}_{i j}^{O} \\ {\overset{\cdot}{V}}_{i}^{U} \\ 0 \end{matrix}] = [\begin{matrix} E & 0 \\ Y_{i}^{O O} & Y_{i}^{O U} \\ Y_{i j}^{O O} & Y_{i j}^{O U} \\ 0 & E \\ Y_{i}^{U O} & Y_{i}^{U U} & - Y_{i}^{U} \end{matrix}] [\begin{matrix} {\overset{\cdot}{V}}_{i}^{O} \\ {\overset{\cdot}{V}}_{i}^{U} \end{matrix}] - - - (12)

taking the node current equation as a linear equation of linear calculation, and carrying out linear state estimation by the formula (3).

5. The method of claim 1, wherein the method comprises the steps of: in the process of carrying out nonlinear state estimation, PMU voltage measurement information and phase angle measurement information, PMU power measurement information and PMU current measurement information are respectively introduced to carry out nonlinear state estimation.

6. The method of claim 5, wherein the PMU measurement information is introduced into the grid state estimation method, and the method further comprises: the specific process of introducing PMU voltage measurement information and phase angle measurement information to carry out nonlinear state estimation comprises the following steps:

1) directly adding a PMU node voltage phasor measurement equation into the nonlinear state estimation, wherein the PMU voltage and phase angle measurement equation is as follows:

\{\begin{matrix} V_{i}^{m} = V_{i} \\ θ_{i}^{m} = θ_{i} \end{matrix} - - - (13)

wherein,andPMU voltage measurement information and phase angle measurement information, V, of node i_iAnd theta_iThe voltage and the phase angle of the node i are shown, the corresponding element of the Jacobian matrix is 1, and other elements are 0;

2) introducing a power phase angle difference;

introducing new quantity measurement theta to large power grid nonlinear state estimation containing PMU phase angle measurement_ijWhere θ between node i and node j_ij＝θ_i-θ_j，θ_jIs the phase angle of node j; then there is

\{\begin{matrix} \frac{{dθ}_{i j}}{{dθ}_{i}} = 1 \\ \frac{{dθ}_{i j}}{{dθ}_{j}} = - 1 \end{matrix} - - - (14) .

7. The method of claim 5, wherein the PMU measurement information is introduced into the grid state estimation method, and the method further comprises: the specific process of introducing PMU power measurement information to carry out nonlinear state estimation comprises the following steps:

\{\begin{matrix} P_{i}^{m} = P_{i} \\ Q_{i}^{m} = Q_{i} \end{matrix} - - - (15)

wherein,andactive and reactive power measurement information, P, for node i, respectively_iAnd Q_iRespectively the active power and the reactive power of the node i; according to the types of node injection power and branch power, the corresponding Jacobian matrix coefficient of the PMU power measurement is consistent with the corresponding coefficient of the SCADA measured power quantity.

8. The method of claim 5, wherein the PMU measurement information is introduced into the grid state estimation method, and the method further comprises: the specific process of introducing PMU current measurement information to carry out nonlinear state estimation is divided into the following two cases:

1) convert the current magnitude into branch current, having

\{\begin{matrix} P_{i j} = V_{i} I_{i} c o s (θ_{u i} - θ_{I i}) \\ Q_{i j} = V_{i} I_{i} s i n (θ_{u i} - θ_{I i}) \end{matrix} - - - (16)

Wherein, P_ijAnd Q_ijRespectively the active power and reactive power of a branch ij between node I and node j, I_iIs the current of node i, θ_uiAnd theta_IiRespectively is a voltage phase angle and a current phase angle of the node i; p_ijAnd Q_ijIs weighted according to the following errorCalculating a difference transfer formula;

R_{P_{i j}} = {(\frac{\partial P_{i j}}{\partial V_{i}} σ_{V_{i}})}^{2} + {(\frac{\partial P_{i j}}{\partial I_{i}} σ_{I_{i}})}^{2} + {(\frac{\partial P_{i j}}{\partial θ_{u i}} σ_{θ_{u i}})}^{2} + {(\frac{\partial P_{i j}}{\partial θ_{I i}} σ_{θ_{I i}})}^{2} - - - (17)

R_{Q_{i j}} = {(\frac{\partial Q_{i j}}{\partial V_{i}} σ_{V_{i}})}^{2} + {(\frac{\partial Q_{i j}}{\partial I_{i}} σ_{I_{i}})}^{2} + {(\frac{\partial Q_{i j}}{\partial θ_{u i}} σ_{θ_{u i}})}^{2} + {(\frac{\partial Q_{i j}}{\partial θ_{I i}} σ_{θ_{I i}})}^{2} - - - (18)

wherein,andthe error variance of the equivalent active measurement and the equivalent reactive measurement,andare respectively a voltage amplitude V_iCurrent I_iPhase angle of voltage theta_uiAnd phase angle theta of injected current_IiThe corresponding standard deviation; p_ijAnd Q_ijAre respectively expressed as

R_{P_{i j}}^{- 1} = \frac{1}{R_{P_{i j}}}

And

R_{Q_{i j}}^{- 1} = \frac{1}{R_{Q_{i j}}};

converting branch current vector of node configured with PMU into adjacent node voltage vector

{\overset{\cdot}{V}}_{j} = \frac{{\overset{\cdot}{I}}_{i j} - (Y_{i 0} + Y_{i j}) {\overset{\cdot}{V}}_{i}}{- Y_{i j}} - - - (19)

Wherein,is the phase voltage at the node j,is the current vector of branch ij, Y_i0Is the capacitance to ground of node i, Y_ijElements of a node admittance matrix;the weight of the error is calculated according to the following error transfer formula;

R_{{\overset{\cdot}{V}}_{j}} = {(\frac{\partial {\overset{\cdot}{V}}_{j}}{\partial V_{i}} σ_{V_{i}})}^{2} + {(\frac{\partial {\overset{\cdot}{V}}_{j}}{\partial θ_{u i}} σ_{θ_{u i}})}^{2} + {(\frac{\partial {\overset{\cdot}{V}}_{j}}{\partial I_{i j}} σ_{I_{i j}})}^{2} + {(\frac{\partial {\overset{\cdot}{V}}_{j}}{\partial θ_{i j}^{I}} σ_{θ_{i j}^{I}})}^{2} - - - (20)

wherein,is the error variance of the equivalent voltage vector measurement,andrespectively a voltage amplitude V_iPhase angle of voltage theta_uiBranch current I_ijPhase angle of sum branch currentThe corresponding standard deviation;is expressed as

2) Constructing a pseudo quantity measurement;

measurement of structural false quantityBy rotation of-theta_iAngle of (A) toTheta of_iThe variable becomes 0, thereby fixing the angle of the i end of the branch ij and constructing the phase angle difference theta_ijUsing theta_ijThe decoupling is performed as follows:

\begin{matrix} {\overset{\cdot}{I}}_{i j .0} = {\overset{\cdot}{I}}_{i j} e^{- {jθ}_{i}} = [y_{i j} ({\overset{\cdot}{V}}_{i} - {\overset{\cdot}{V}}_{j}) + y_{i 0} {\overset{\cdot}{V}}_{i}] e^{- {jθ}_{i}} = y_{i j} (V_{i} - V_{j} e^{- {jθ}_{i j}}) + y_{i 0} V_{i} \\ = (g + j b) [V_{i} - V_{j} ({cosθ}_{i j} - {jsinθ}_{i j})] + {jy}_{i c} V_{i} \end{matrix} - - - (21)

wherein,for constructed rotational false quantity measurement, y_ijFor admittance of branch ij, y_i0For the admittance to ground of the i-terminal of the line, y_icThe capacitance reactance to the ground of the branch ij is g and b are respectively the conductance and the susceptance of the branch ij;

will be provided withDecomposition into real partsAnd imaginary partTwo variables of

\{\begin{matrix} I_{i j .0}^{r e} = {gV}_{i} - {gV}_{j} {cosθ}_{i j} - {bV}_{j} {sinθ}_{i j} \\ I_{i j .0}^{i m} = {gV}_{j} {sinθ}_{i j} + {bV}_{i} - {bV}_{j} {cosθ}_{i j} + y_{i c} V_{i} \end{matrix} - - - (22)

Derivation of a deviation is obtained by

\{\begin{matrix} \frac{\partial I_{i j .0}^{r e}}{\partial θ_{i}} = {gV}_{j} {sinθ}_{i j} - {bV}_{j} {cosθ}_{i j} \\ \frac{\partial I_{i j .0}^{r e}}{\partial V_{i}} = g \\ \frac{\partial I_{i j .0}^{i m}}{\partial θ_{i}} = {gV}_{j} {cosθ}_{i j} + {bV}_{j} {sinθ}_{i j} \\ \frac{\partial I_{i j .0}^{i m}}{\partial V_{i}} = b + y_{i c} \end{matrix} - - - (23)

\{\begin{matrix} \frac{\partial I_{i j .0}^{r e}}{\partial θ_{j}} = - {gV}_{j} {sinθ}_{i j} + {bV}_{j} {cosθ}_{i j} \\ \frac{\partial I_{i j .0}^{r e}}{\partial V_{j}} = - {gcosθ}_{i j} - {bsinθ}_{i j} \\ \frac{\partial I_{i j .0}^{i m}}{\partial θ_{j}} = - {gV}_{j} {cosθ}_{i j} + {bV}_{j} {sinθ}_{i j} \\ \frac{\partial I_{i j .0}^{i m}}{\partial V_{j}} = {gsinθ}_{i j} - {bcosθ}_{i j} \end{matrix} - - - (24)

For a high voltage transmission system, r is the line resistance and x is the line reactance, then r < x, V_i≈V_j＝V₀In which V is₀Is a reference voltage, θ_ijClose to 0, so that g < b, cos θ_ij≈1，sinθ_ijIs approximately equal to 0 and simplified by gsin theta_ij＜＜bcosθ_ij，|gcosθ_ij±bsinθ_ij|＜＜|gsinθ_ij±bcosθ_ij|；

The equations (23) and (24) are simplified by

\{\begin{matrix} \frac{\partial I_{i j .0}^{r e}}{\partial θ_{i}} = - {bV}_{0} \\ \frac{\partial I_{i j .0}^{r e}}{\partial V_{i}} = 0 \\ \frac{\partial I_{i j .0}^{i m}}{\partial θ_{i}} = 0 \\ \frac{\partial I_{i j .0}^{i m}}{\partial V_{i}} = b + y_{i c} \end{matrix} - - - (25)

\{\begin{matrix} \frac{\partial I_{i j .0}^{r e}}{\partial θ_{j}} = {bV}_{0} \\ \frac{\partial I_{i j .0}^{r e}}{\partial V_{j}} = 0 \\ \frac{\partial I_{i j .0}^{i m}}{\partial θ_{i}} = 0 \\ \frac{\partial I_{i j .0}^{i m}}{\partial V_{i}} = - b \end{matrix} - - - (26)

The measurement of the rotating pseudo quantity realizes decoupling, has

(\begin{matrix} {ΔI}_{i j .0}^{r e} \\ {ΔI}_{i j .0}^{i m} \end{matrix}) = (\begin{matrix} - B^{'} & 0 \\ 0 & B^{''} \end{matrix}) (\begin{matrix} V_{0} Δ θ \\ Δ v \end{matrix}) - - - (27)

Wherein B 'and B' are each V₀The coefficient matrixes corresponding to the delta theta and the delta v are constants under the condition that the network topology and the parameters are not changed; Δ θ and Δ v are the phase angle increment and the voltage increment, respectively.