CN-122019947-A - Automatic power distribution network line parameter identification method based on augmented state estimation

CN122019947ACN 122019947 ACN122019947 ACN 122019947ACN-122019947-A

Abstract

The invention discloses an automatic identification method of power distribution network line parameters based on augmented state estimation, which comprises the steps of obtaining an augmented state vector comprising a state vector and a preset line parameter vector, constructing a nonlinear measurement function, calculating a conductance/susceptance estimated value of each line and an active power/reactive power/current amplitude estimated value of each node, obtaining a conductance/susceptance measured value of each line, obtaining an active power/reactive power/current amplitude measured value of each node, calculating a conductance/susceptance residual of each line and an active power/reactive power/current amplitude residual of each node, constructing an augmented jacobian matrix, calculating a correction vector, correcting the augmented state vector through the correction vector, iterating until the result converges, and outputting the augmented state vector after the result converges. When the running state of the power grid is solved, the circuit parameters are corrected, so that the real parameters after the environmental or physical factors are changed are obtained, and the accuracy of the parameters is improved.

Inventors

CHEN WENJIN
CAI JUNYU
WU LIFENG
XIE CHENG
CHEN XIN
SHI ZHENGYUAN
ZHU XIAOJIE
ZHANG DUXI
YAO YING

Assignees

国网浙江省电力有限公司电力科学研究院

Dates

Publication Date: 20260512
Application Date: 20260413

Claims (10)

1. An automatic power distribution network line parameter identification method based on augmented state estimation is characterized by comprising the following steps: The method comprises the steps of obtaining an augmented state vector X comprising a state vector X s and a preset line parameter vector X p , wherein the state vector X s comprises a voltage amplitude subvector V and a voltage phase angle subvector theta, the ith dimension of the voltage amplitude subvector V is the voltage amplitude output by the ith node, the ith dimension of the voltage phase angle subvector theta is the voltage phase angle output by the ith node, the line parameter vector comprises a resistor subvector R, a reactor subvector X and a susceptance subvector B, and the ith dimension of the resistor subvector R, the reactor subvector X and the susceptance subvector B are all related to the physical parameters of a line between the ith node and the (i+1) th node, and i represents an index; Constructing a nonlinear measurement function, and calculating a conductance/susceptance estimation value of each line and an active power/reactive power/current amplitude estimation value of each node according to the nonlinear measurement function, a state vector x s and a line parameter vector x p ; and constructing an augmentation jacobian matrix, calculating a correction vector according to the conductance/susceptance residual error of each line, the active power/reactive power/current amplitude residual error of each node and the augmentation jacobian matrix, correcting the augmentation state vector x through the correction vector, iterating until the result is converged, and outputting the augmentation state vector x after the result is converged.
2. The automatic identification method for power distribution network line parameters based on augmented state estimation according to claim 1, wherein the ith dimension of the resistor sub-vector R is a line resistance between the ith node and the (i+1) th node, the ith dimension of the reactor sub-vector X is a line reactance between the ith node and the (i+1) th node, and the ith dimension of the susceptance sub-vector B is a line susceptance between the ith node and the (i+1) th node.
3. The method for automatically identifying parameters of a power distribution network based on augmented state estimation according to claim 2, wherein the nonlinear measurement functions include an admittance parameter conversion function, an active power measurement function, a reactive power measurement function, and a current amplitude measurement function.
4. A method for automatically identifying parameters of a power distribution network based on augmented state estimation according to claim 3, wherein calculating the conductance/susceptance estimate of each line comprises: And calculating the conductance/susceptance estimated value of each line according to the admittance parameter conversion function, wherein the formula for calculating the conductance/susceptance estimated value of the line between the ith node and the (i+1) th node is as follows: ; Wherein, R i is the ith dimension of the resistor sub-vector R, X i is the ith dimension of the reactor sub-vector X, g i is the estimated value of the conductance of the line between the ith node and the (i+1) th node, and b i is the estimated value of the susceptance of the line between the ith node and the (i+1) th node.
5. The method for automatically identifying parameters of a power distribution network based on augmented state estimation according to claim 4, wherein calculating the active power/reactive power estimation value of each node comprises: calculating the active power estimated value of each node according to the active power measurement function, wherein the formula for calculating the active power estimated value of the ith node is as follows: ; Wherein P mean (i) is an active power estimated value of the ith node, V i is a voltage amplitude of the ith node, V i+1 is a voltage amplitude of the (i+1) th node, theta i is a voltage phase angle of the ith node, theta i+1 is a voltage phase angle of the (i+1) th node, and N is the number of all nodes; and calculating the reactive power estimated value of each node according to the reactive power measurement function, wherein the formula for calculating the reactive power estimated value of the ith node is as follows: ; Wherein Q mean (i) is the reactive power estimate of the i-th node.
6. The method for automatically identifying parameters of a power distribution network based on augmented state estimation according to claim 5, wherein calculating the current amplitude estimation value of each node comprises: Calculating the current amplitude estimated value of each node according to the current amplitude measurement function, wherein a formula for calculating the current amplitude estimated value of the ith node is as follows: ; wherein I (I) is an estimated value of the current amplitude of the I-th node.
7. The method for automatically identifying parameters of a power distribution network based on augmented state estimation according to claim 1, wherein calculating conductance/susceptance residuals and active power/reactive power/current magnitude residuals comprises: Calculating the difference between the conductance measured value and the conductance estimated value, and recording the difference as a conductance residual; Calculating the difference between the susceptance measured value and the susceptance estimated value, and recording the difference as a susceptance residual error; Calculating the difference between the reactive power measured value and the reactive power estimated value, and recording the difference as a reactive power residual error; Calculating the difference between the active power measured value and the active power estimated value, and recording the difference as an active power residual error; and calculating the difference between the current amplitude measured value and the current amplitude estimated value, and recording the difference as a current amplitude residual error.
8. The method for automatically identifying parameters of a power distribution network based on augmented state estimation according to claim 7, wherein calculating the correction vector in the kth iteration comprises: in the kth iteration, a residual vector Δz (k) is constructed, wherein the residual vector Δz (k) in the kth iteration satisfies: Conductance residual subvector Is the conductance residual of the line between the ith node and the (i+1) th node, susceptance residual subvector Is the susceptance residual of the line between the ith node and the (i+1) th node, the active power residual subvector The ith dimension of (a) is the active power residual of the ith node, the reactive power residual subvector Is the reactive power residual of the ith node, the current amplitude residual subvector The ith dimension of (a) is the current amplitude residual of the ith node; the correction vector deltax (k) in the kth iteration is calculated, where the calculation formula is: ; Wherein W is a preset weight matrix, and H k is an augmented Jacobian matrix in the kth iteration.
9. The method for automatically identifying parameters of a power distribution network based on augmented state estimation according to claim 8, wherein constructing an augmented jacobian matrix comprises: Construction of the variables to be solved And a measurement vector The ith dimension of the active power subvector P is the active power of the ith node, the ith dimension of the reactive power subvector Q is the reactive power of the ith node, and the ith dimension of the current amplitude subvector I is the current amplitude of the ith node; Constructing an augmented jacobian matrix, wherein the augmented jacobian matrix H satisfies: ; Wherein, the As the partial derivative of active power with respect to voltage phase angle, As the partial derivative of active power with respect to voltage amplitude, As the partial derivative of the active power with respect to the resistance, Is the partial derivative of active power to reactance; as the partial derivative of reactive power with respect to the voltage phase angle, As the partial derivative of reactive power with respect to voltage amplitude, As the partial derivative of reactive power with respect to resistance, The partial derivative of reactive power to reactance; As the partial derivative of the current amplitude with respect to the voltage phase angle, As the partial derivative of the current amplitude with respect to the voltage amplitude, Is the partial derivative of the current amplitude resistance, Is the partial derivative of the current amplitude with respect to reactance.
10. The method according to claim 1, wherein the convergence of the result is determined in response to the modulus of the correction vector being smaller than a predetermined threshold or the number of iterations reaching a predetermined value.

Description

Automatic power distribution network line parameter identification method based on augmented state estimation Technical Field The invention relates to the technical field of power distribution networks, in particular to an automatic power distribution network line parameter identification method based on augmented state estimation. Background The distribution network refers to a power network that receives electric energy from a power transmission network or a regional power plant, and distributes the electric energy locally or step by step according to voltage through a distribution facility. The distribution network consists of lines (usually overhead or underground), cables, towers, distribution transformers, disconnectors, reactive compensators, some accessory facilities, etc. Distribution lines are power lines or circuits that carry power from substations to homes, businesses, and other buildings. It is an important component of the power grid because it delivers power at a lower voltage than the transmission line delivering power over long distances. The parameters of the resistance, reactance and the like of the distribution network lines are the only language for quantifying and mapping the electrical characteristics (heating, magnetic field and electric field effect) of the physical entities into a digital system. Thus, the distribution network line parameters (mainly including resistance, reactance, susceptance) are the basis for constructing the distribution network physical model. However, the parameters of the distribution network lines generally depend on factory nominal data, and the data may drift due to environmental factors such as temperature, aging or corrosion in long-term operation, so that the parameters are inaccurate. Disclosure of Invention In order to solve the technical problem that the parameter technology of the power distribution network line may not be accurately determined, the invention provides an automatic power distribution network line parameter identification method based on augmented state estimation, which corrects line parameters when solving the running state of a power grid, thereby acquiring real parameters after the change of environmental or physical factors so as to improve the accuracy of the parameters. The technical scheme includes that the automatic identification method for the power distribution network line parameters based on the augmented state estimation comprises the steps of obtaining an augmented state vector X comprising a state vector X s and a preset line parameter vector X p, wherein the state vector X s comprises a voltage amplitude subvector V and a voltage phase angle subvector theta, the ith dimension of the voltage amplitude subvector V is the voltage amplitude value output by the ith node, the ith dimension of the voltage phase angle subvector theta is the voltage phase angle output by the ith node, the line parameter vector comprises a resistor subvector R, a reactance subvector X and a susceptance subvector B, the ith dimension of the resistor subvector R, the reactance subvector X and the susceptance subvector B are related to physical parameters of a line between the ith node and the ith+1 node, i represents an index, constructing a nonlinear measurement function, calculating a power/reactive power/current estimation value of each line and an active power/reactive power/current estimation value of each node according to the nonlinear measurement function, the state vector X s and the line parameter vector X p, obtaining a measured value of each line power/reactive power of each line power/correction residual error matrix and the current gain/reactive power correction of each line/power correction matrix, iterating until the result is converged, and outputting the augmented state vector x after the result is converged. Preferably, the ith dimension of the resistor sub-vector R is a line resistance between the ith node and the (i+1) th node, the ith dimension of the reactor sub-vector X is a line reactance between the ith node and the (i+1) th node, and the ith dimension of the susceptance sub-vector B is a line susceptance between the ith node and the (i+1) th node. Preferably, the nonlinear measurement function includes an admittance parameter transfer function, an active power measurement function, a reactive power measurement function, and a current magnitude measurement function. Preferably, calculating the conductance/susceptance estimate for each line includes calculating a conductance/susceptance estimate for each line according to the admittance parameter transfer function, wherein the formula for calculating the conductance/susceptance estimate for the line between the i-th node and the i+1th node is: 。 Wherein, R i is the ith dimension of the resistor sub-vector R, X i is the ith dimension of the reactor sub-vector X, a line between the ith node and the (i+1) th node, g i is a conductance estimated value, and b i is a suscep