CN-121978581-A - Method, system, equipment and medium for on-line monitoring of short-circuit parameters of active distribution network

CN121978581ACN 121978581 ACN121978581 ACN 121978581ACN-121978581-A

Abstract

The invention discloses an on-line monitoring method, system, equipment and medium for short-circuit parameters of an active distribution network, which belong to the technical field of short-circuit parameter monitoring of the active distribution network and comprise the steps of collecting operation data by applying excitation disturbance to a distributed power supply, delaying embedding to construct an extended phase space state vector, identifying a current limiting trigger point from an evolution track, extracting extreme point fitting current limiting boundaries at a plurality of working conditions, establishing a state evolution model, iteratively evolving to a to-be-detected working condition to a stable state to extract short-circuit current characteristics, establishing a mapping relation between margin and the short-circuit current characteristics, and outputting a short-circuit current predicted value and a dominant current limiting boundary. According to the invention, the multi-physical domain parameters are converted into the state vectors, and the short-circuit process is simulated through iterative evolution, so that the on-line monitoring and prediction are realized, the equipment damage risk of an actual short-circuit test is avoided, and the short-circuit current prediction precision is improved.

Inventors

XU LIANGGANG
LIU WENMING
LU LIJUAN
Zhu Handan
DU XIANRONG
JI BAOXIAN
PAN JIAN
ZHANG YINGZI
ZHENG WEI
LI XINYU

Assignees

贵州浦源通科技有限公司

Dates

Publication Date: 20260505
Application Date: 20260331

Claims (10)

1. An active distribution network short-circuit parameter on-line monitoring method is characterized by comprising the following steps: Applying excitation disturbance to a distributed power supply, collecting operation data under the excitation disturbance, embedding a construction state vector into the operation data in a delayed manner, recording a sequence formed by the state vectors at different moments as an evolution track, and identifying a current limiting trigger point from the evolution track; repeatedly identifying the current limiting trigger points in a plurality of working conditions, extracting extreme points from the current limiting trigger points in the plurality of working conditions, and fitting the extreme points to obtain a current limiting boundary; calculating the directed distance from the evolution track to the current limiting boundary, classifying the evolution track according to the directed distance change, and establishing a state evolution model for each type of track; applying short circuit disturbance to a working condition to be tested to obtain an initial state, selecting the state evolution model according to the category to which the initial state belongs, iteratively evolving to a steady state by using the model, and extracting short circuit current characteristics from the evolution process; And calculating a normalized directional distance from the initial state to the current limiting boundary as a margin, establishing a mapping relation between the margin and the short-circuit current characteristic, and outputting a short-circuit current predicted value and a dominant current limiting boundary.
2. The method for on-line monitoring of short-circuit parameters of active distribution network according to claim 1, wherein, The operation data comprises parameter time sequences of a plurality of physical domains; The step of constructing the state vector by delaying and embedding the operation data comprises the steps of respectively delaying and embedding each parameter time sequence in parameter time sequences of a plurality of physical domains to obtain an embedded vector, and splicing the embedded vectors to construct the state vector; Extracting extreme points from the current limiting trigger points of a plurality of working conditions comprises extracting an extreme point subset of which each dimension of the embedded vector reaches an extreme value from the current limiting trigger points; fitting the extreme points to obtain the current limiting boundary comprises fitting the extreme point subsets to obtain the current limiting boundary respectively to obtain a plurality of current limiting boundaries.
3. The method for on-line monitoring of short-circuit parameters of active distribution network according to claim 2, wherein, The parameter time sequences of the plurality of physical domains comprise a first electrical parameter time sequence, a second electrical parameter time sequence and a thermal parameter time sequence; The first electrical parameter time series delay is embedded to obtain a first embedded vector, the second electrical parameter time series delay is embedded to obtain a second embedded vector, the thermal parameter time series delay is embedded to obtain a third embedded vector, and the first embedded vector, the second embedded vector and the third embedded vector are spliced to construct an extended phase space state vector; Extracting a first extreme value point set with the first embedded vector dimension reaching an extreme value, a second extreme value point set with the second embedded vector dimension reaching the extreme value and a third extreme value point set with the third embedded vector dimension reaching the extreme value from the current limiting trigger point in the extended phase space; Fitting the first extreme point set, the second extreme point set and the third extreme point set respectively, and obtaining a first current limiting boundary, a second current limiting boundary and a third current limiting boundary in the extended phase space, wherein the first current limiting boundary, the second current limiting boundary and the third current limiting boundary jointly enclose a constraint feasible region.
4. An active distribution network short-circuit parameter on-line monitoring method according to claim 3, wherein, Taking a first characteristic time scale as delay time when the first electrical parameter time series is delayed and embedded, taking a second characteristic time scale as delay time when the second electrical parameter time series is delayed and embedded, and taking a third characteristic time scale as delay time when the thermal parameter time series is delayed and embedded; The first characteristic time scale is determined according to the physical response characteristic of the first electrical parameter, the second characteristic time scale is determined according to the physical response characteristic of the second electrical parameter, and the third characteristic time scale is determined according to the physical response characteristic of the thermal parameter.
5. The method for on-line monitoring of short-circuit parameters of active distribution network according to claim 4, wherein, Calculating a first directed distance from each track point on the evolution track to a first current limiting boundary, a second directed distance from each track point to a second current limiting boundary and a third directed distance from each track point to a third current limiting boundary; Identifying a first sign change moment when the first directed distance is negatively changed from positive rotation, a second sign change moment when the second directed distance is negatively changed from positive rotation and a third sign change moment when the third directed distance is negatively changed from positive rotation, wherein the first sign change moment is a moment when the evolution track passes through a first current limiting boundary, the second sign change moment is a moment when the evolution track passes through a second current limiting boundary, and the third sign change moment is a moment when the evolution track passes through a third current limiting boundary; And determining the triggering sequence of the current limiting boundary according to the time sequence of the first symbol change moment, the second symbol change moment and the third symbol change moment, and classifying the evolution tracks with the same triggering sequence into the same category.
6. The method for on-line monitoring of short-circuit parameters of active distribution network according to claim 5, wherein, Calculating a directional distance from the initial state to the current limiting boundary, determining a category to which the initial state belongs according to a positive and negative sign combination of the directional distance, and selecting a state evolution model of the category; performing single-step evolution on the initial state by using the state evolution model to obtain a state at the next moment; calculating a directed distance from the next time state to the current limiting boundary; Determining to cross the current limit boundary when the directional distance symbol changes; Re-determining the category according to the traversed directed distance symbol combination; switching to a new class of state evolution model; And repeating at least one round of single-step evolution, directed distance calculation, crossing judgment, category determination and model switching on the state at the next moment until the difference value between two adjacent evolution states is smaller than a preset convergence threshold.
7. The method for on-line monitoring of short-circuit parameters of active distribution network according to claim 6, wherein, The establishing of the mapping relation between the margin and the short-circuit current characteristic comprises the steps of carrying out multidimensional interpolation on the margin of a plurality of working conditions and the short-circuit current characteristic to construct an interpolation function; Collecting operation data of a distributed power supply in normal operation, embedding a state vector into the operation data in a delayed manner, calculating a normalized directional distance from the state vector to the current limiting boundary as a margin, inputting the margin into the interpolation function to obtain a short-circuit current predicted value, calculating a directional distance from the state vector to the current limiting boundary, determining a category to which the state vector belongs according to a positive and negative sign combination of the directional distance, identifying a first triggered current limiting boundary from a triggering sequence of the category as a dominant current limiting boundary, and outputting the short-circuit current predicted value and the dominant current limiting boundary.
8. An active distribution network short-circuit parameter on-line monitoring system, applying the method for on-line monitoring of the active distribution network short-circuit parameter according to any one of claims 1 to 7, comprising the following steps: The excitation control module is used for controlling the application of excitation disturbance to the distributed power supply; The data acquisition module is used for acquiring operation data under excitation disturbance; the phase space reconstruction module is used for embedding the running data into a state vector in a delayed manner, and recording a sequence formed by the state vectors at different moments as an evolution track; The current limiting trigger point identification module is used for identifying a current limiting trigger point from the evolution track; The boundary modeling module is used for extracting extreme points from the current limiting trigger points of a plurality of working conditions and fitting the extreme points to obtain a current limiting boundary; The track classification module is used for calculating the directed distance from the evolution track to the current limiting boundary, classifying the evolution track according to the directed distance change and establishing a state evolution model for each type of track; The short circuit simulation module is used for applying short circuit disturbance to a working condition to be tested to obtain an initial state, selecting the state evolution model according to the category to which the initial state belongs, iteratively evolving to a steady state by using the model, and extracting short circuit current characteristics from the evolution process; the mapping construction module is used for calculating the normalized directional distance from the initial state to the current limiting boundary as a margin and establishing a mapping relation between the margin and the short-circuit current characteristic; and the on-line monitoring module is used for outputting the short-circuit current predicted value and the dominant current limiting boundary.
9. A computer device comprising a memory and a processor, the memory storing a computer program, characterized in that the processor, when executing the computer program, implements the steps of an active distribution network short circuit parameter on-line monitoring method according to any one of claims 1 to 7.
10. A computer readable storage medium having stored thereon a computer program, characterized in that the computer program when executed by a processor implements the steps of an active distribution network short circuit parameter on-line monitoring method according to any of claims 1 to 7.

Description

Method, system, equipment and medium for on-line monitoring of short-circuit parameters of active distribution network Technical Field The invention relates to the technical field of active distribution network short-circuit parameter monitoring, in particular to an active distribution network short-circuit parameter on-line monitoring method, system, equipment and medium. Background With the large-scale grid connection of distributed power sources, the power distribution network is changed from a single power source to an active power distribution network with multi-source power supply. The distributed power supply is connected with the grid through the power electronic inverter, and the short-circuit current characteristic of the distributed power supply is basically different from that of the traditional synchronous generator. Short-circuit current of the inverter is limited by multiple physical constraints such as controller saturation, power device thermal protection, direct current bus voltage drop and the like, and the constraints are divided into a control domain, a thermal domain and an energy domain and are mutually coupled. The traditional method is independent in each physical domain, and cannot describe a cross-domain coupling mechanism, so that the prediction error of short-circuit current is large. The traditional electromagnetic transient simulation can describe a dynamic process, but has large calculation amount, and is difficult to meet the real-time requirement of online monitoring. The traditional machine learning method lacks of physical interpretability and has weak generalization capability for working conditions outside training data. At present, a short-circuit current prediction method which can accurately describe a multi-domain coupling current limiting mechanism and meet the requirement of on-line monitoring instantaneity is lacking. Disclosure of Invention In view of the above problems, the present invention provides an active distribution network short-circuit parameter on-line monitoring method, system, device and medium. The invention solves the technical problems of how to construct time sequence data of electric parameters of a control domain, electric parameters of an energy domain and thermal parameters of a thermal domain into a state vector capable of reflecting a cross-domain coupling relation, how to identify constraint boundaries of each physical domain from current limiting trigger points of a plurality of working conditions, how to establish state evolution models under different working conditions according to the sequence that evolution tracks cross the constraint boundaries, and how to quickly inquire short-circuit current characteristics and leading current limiting boundaries of working conditions to be tested during online monitoring. In order to solve the technical problems, the invention provides a technical scheme that an active distribution network short-circuit parameter on-line monitoring method comprises the following steps, Applying excitation disturbance to a distributed power supply, collecting operation data under the excitation disturbance, embedding a construction state vector into the operation data in a delayed manner, recording a sequence formed by the state vectors at different moments as an evolution track, and identifying a current limiting trigger point from the evolution track; repeatedly identifying the current limiting trigger points in a plurality of working conditions, extracting extreme points from the current limiting trigger points in the plurality of working conditions, and fitting the extreme points to obtain a current limiting boundary; calculating the directed distance from the evolution track to the current limiting boundary, classifying the evolution track according to the directed distance change, and establishing a state evolution model for each type of track; applying short circuit disturbance to a working condition to be tested to obtain an initial state, selecting the state evolution model according to the category to which the initial state belongs, iteratively evolving to a steady state by using the model, and extracting short circuit current characteristics from the evolution process; And calculating a normalized directional distance from the initial state to the current limiting boundary as a margin, establishing a mapping relation between the margin and the short-circuit current characteristic, and outputting a short-circuit current predicted value and a dominant current limiting boundary. As a preferable scheme of the active distribution network short-circuit parameter on-line monitoring method, the operation data comprises parameter time sequences of a plurality of physical domains; The step of constructing the state vector by delaying and embedding the operation data comprises the steps of respectively delaying and embedding each parameter time sequence in parameter time sequences of a plurality of physical doma