A power distribution network multi-level protection setting value adaptive cooperative calculation method and system

Abstract

The present application relates to the technical field of power system protection, specifically to a multi-level protection setting value adaptive collaborative calculation method and system for distribution network. The method comprises the following steps: analyzing SVG and XML files to construct network topology graph and calculating short-circuit current of each switch node; adopting K-means clustering algorithm to cluster switch nodes and adaptively determining the number of clusters according to the range of short-circuit current; extracting representative paths and performing deduplication processing; identifying main switches according to the clustering results and calculating protection setting values, and distributing setting values to non-main switches by linear interpolation; and outputting complete protection setting value table. The present application realizes full-process automation of protection setting value calculation, significantly improves calculation efficiency and accuracy, has strong adaptive ability, and can quickly respond to changes in power grid structure and operation mode adjustment.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power system protection, in particular to a multi-level protection setting value adaptive collaborative calculation method and system for distribution network. BACKGROUND

[0002] In the distribution network, reasonable setting of relay protection setting value is crucial to ensure the safe and stable operation of the power grid. With the continuous expansion of the scale of the distribution network and the increasing complexity of the network structure, the automation and intelligentization of protection setting value calculation are increasingly urgent.

[0003] The existing technology has the following outstanding problems: first, the distribution network protection setting value calculation usually adopts fixed coordination principles, which is difficult to adapt to complex and variable network structures, especially in high-reliability distribution networks, where the segment method is set by load density or the number of distribution transformers, resulting in different lengths of each section and large differences in short-circuit current levels, and the traditional three-section overcurrent protection coordination method is prone to mismatch of upper and lower switch protection; second, the traditional protection setting value calculation method has low automation degree, and manual collection of network parameters, drawing of equivalent circuit, calculation of short-circuit current, and setting of protection setting value are required, which is time-consuming and labor-intensive and prone to errors; third, the existing method is difficult to adapt to frequent changes in operating mode, and when the line is transferred or connected, the short-circuit current level changes, and the original setting value may be invalid, while adjusting the setting value relies on manual calculation and has slow response. SUMMARY

[0004] The present application provides a multi-level protection setting value adaptive collaborative calculation method and system for distribution network, aiming to solve the problems of manual dependence, low efficiency, error-prone, and difficulty in adapting to complex network structures and operating mode changes in distribution network protection setting value calculation.

[0005] To achieve the above-mentioned purpose, the present application provides the following technical solutions:

[0006] The present application provides a multi-level protection setting value adaptive collaborative calculation method for distribution network, comprising:

[0007] S100: Analyze the SVG file and XML file of the distribution line, and construct the network topology graph of the distribution line; the SVG file provides the connection relationship and hierarchical information of the switch nodes and distribution transformer nodes, and the XML file provides the conductor parameters of the feeder section;

[0008] S200: Calculate the electrical path impedance of each switch node to the root node based on the network topology graph and conductor parameters, and calculate the maximum short-circuit current under the maximum operating mode and the minimum short-circuit current under the minimum operating mode of each switch node in combination with the system impedance on the power supply side;

[0009] S300: using K-means clustering algorithm to cluster the switch nodes with maximum short-circuit current as clustering features; adaptively determining the number of clusters according to the range of maximum short-circuit current, and sorting and numbering each cluster in descending order of cluster center value;

[0010] S400: extracting the paths from the root node to each leaf node in the network topology graph, grouping according to the switch combination on the path, and retaining the path with the minimum maximum short-circuit current of the leaf node in each group as the representative path;

[0011] S500: identifying the main switch according to the clustering sorting result on the representative path; according to the clustering combination in the network, for the main switches of adjacent two levels, calculating the protection setting value of the main switch of the current level based on the maximum short-circuit current of the main switch of the next level and the minimum short-circuit current of the main switch of the current level; for the non-main switch between the two main switches, using the linear interpolation of the protection setting values of the two main switches to obtain the protection setting value of the non-main switch;

[0012] S600: outputting the protection setting value table of all switches.

[0013] As a preferred technical scheme of the present application, the construction of the power distribution line network topology graph comprises:

[0014] Parsing the SVG file to extract the switch nodes and distribution transformer nodes and their connection relationship, and constructing an initial network graph;

[0015] Using the breadth-first search algorithm to calculate the level information of the root node to each node, the root node level is 0, and the nodes directly connected with the root node level is 1, and the level number increases by 1 for each additional path length;

[0016] Checking the level relationship of each connection edge, retaining the connection with a level difference of 1, and removing the connection with a level difference greater than 1 to obtain the power distribution line SVG topology graph;

[0017] Parsing the XML file to extract bus segment information, switch device information and line segment information, establishing the electrical connection relationship between devices, and obtaining the power distribution line XML topology graph.

[0018] As a preferred technical scheme of the present application, the calculation of the maximum short-circuit current and the minimum short-circuit current of each switch node under the maximum operating mode and the minimum operating mode comprises:

[0019] Calculating the shortest electrical path from each switch node to the root node, and calculating the total resistance and total reactance of the path according to the wire type and length on the path;

[0020] Adding the total resistance and total reactance of the path to the resistance component and reactance component corresponding to the system impedance on the power supply side to obtain the total resistance and total reactance from the power supply to each switch node;

[0021] calculating total impedance according to total resistance and total reactance;

[0022] calculating maximum short-circuit current and minimum short-circuit current of each switching node based on total impedance.

[0023] As a preferred technical solution of the present application, the calculation of total impedance according to total resistance and total reactance comprises:

[0024] in the maximum operation mode, adding the minimum resistance component of the system impedance on the power side to the total resistance of the path to obtain the minimum total resistance, adding the minimum reactance component of the system impedance on the power side to the total reactance of the path to obtain the minimum total reactance, and calculating the minimum total impedance according to the minimum total resistance and the minimum total reactance;

[0025] in the minimum operation mode, adding the maximum resistance component of the system impedance on the power side to the total resistance of the path to obtain the maximum total resistance, adding the maximum reactance component of the system impedance on the power side to the total reactance of the path to obtain the maximum total reactance, and calculating the maximum total impedance according to the maximum total resistance and the maximum total reactance.

[0026] As a preferred technical solution of the present application, the adaptive determination of the number of clusters according to the range of maximum short-circuit current comprises:

[0027] calculating the difference between the maximum value and the minimum value of the maximum short-circuit current of all switching nodes to obtain the range of maximum short-circuit current;

[0028] comparing the range of maximum short-circuit current with a preset range threshold, and determining the corresponding number of clusters according to the threshold interval in which the range of maximum short-circuit current is located.

[0029] As a preferred technical solution of the present application, the identification of the main switch comprises:

[0030] identifying the switch at the root node as the root switch;

[0031] when there are multiple clusters, sequentially identifying the first switch of each cluster on the representative path as the main switch of the cluster according to the cluster order.

[0032] As a preferred technical solution of the present application, the calculation of the protection setting value of the main switch comprises:

[0033] identifying the cluster combination type existing in the network;

[0034] for the main switches of adjacent two levels, calculating the protection setting value of the main switch of the current level according to the maximum short-circuit current of the main switch of the next level and the minimum short-circuit current of the main switch of the current level;

[0035] for the main switch of the last level, calculating the protection setting value thereof according to the maximum short-circuit current and the minimum short-circuit current of the leaf node.

[0036] As a preferred technical solution of the present application, the linear interpolation of the protection setting value of the non-main switch between the two main switches includes:

[0037] Identifying the non-main switch between the two adjacent main switches;

[0038] Obtaining the protection setting value of the two main switches;

[0039] According to the position of the non-main switch on the path, the protection setting value of the non-main switch is calculated based on the protection setting value of the two main switches by using the linear interpolation method.

[0040] As a preferred technical solution of the present application, the output of the protection setting value table of all switches includes:

[0041] Integrating the protection setting values of the main switches at each level;

[0042] Integrating the protection setting values of the non-main switches between the main switches;

[0043] Forming a protection setting value table containing switch names and protection setting values.

[0044] The present application also proposes a multi-level protection setting value adaptive collaborative calculation system for a power distribution network, comprising:

[0045] A topology construction module for parsing SVG files and XML files of the power distribution line and constructing a power distribution line network topology graph; the SVG files provide connection relationships and hierarchical information of switch nodes and distribution transformer nodes, and the XML files provide conductor parameters of feeder sections;

[0046] A short-circuit calculation module for calculating electrical path impedance of each switch node to the root node based on the network topology graph and the conductor parameters, and combining system impedance on the power supply side to calculate maximum short-circuit current of each switch node under maximum operating mode and minimum short-circuit current under minimum operating mode;

[0047] An intelligent clustering module for clustering switch nodes by using K-means clustering algorithm with maximum short-circuit current as the clustering feature; adaptively determining the number of clusters according to the range of maximum short-circuit current, and sorting and numbering each cluster in descending order of the cluster center value;

[0048] A path optimization module for extracting paths from the root node to each leaf node in the network topology graph, grouping according to switch combinations on the path, and retaining the path with the minimum maximum short-circuit current of the leaf node in each group as the representative path;

[0049] The setting calculation module is used to identify the main switches on representative paths based on the clustering results; based on the clustering combination in the network, for two adjacent main switches, the protection setting of the main switch at this level is calculated based on the maximum short-circuit current of the next-level main switch and the minimum short-circuit current of the main switch at this level; for non-main switches between two main switches, the protection setting of the non-main switches is obtained by linear interpolation using the protection setting of the two main switches.

[0050] The result output module is used to output the protection setting table for all switches.

[0051] The beneficial effects of this invention are:

[0052] 1. This invention achieves adaptive configuration of protection levels by integrating topology information from SVG files and conductor parameter information from XML files, combined with a K-means intelligent clustering algorithm based on short-circuit current characteristics. Compared to the traditional fixed three-segment protection coordination method, this invention can adaptively determine the protection hierarchy system according to the actual short-circuit current distribution of the network, effectively solving the protection mismatch problem caused by uneven distribution network segments and large differences in short-circuit currents.

[0053] 2. This invention innovatively achieves accurate calculation of main switch settings and reasonable allocation of non-main switch settings by combining path optimization deduplication technology and linear interpolation algorithms. This method of combining hierarchical calculation and interpolation eliminates redundant calculations and improves efficiency while ensuring smooth transition and precise coordination of multi-level protection settings, avoiding protection dead zones and over-level tripping problems. Attached Figure Description

[0054] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0055] Figure 1 This is a flowchart illustrating the adaptive collaborative calculation method for multi-level protection settings in a power distribution network according to the present invention.

[0056] Figure 2 This is a schematic diagram of the structure of a multi-level protection setting adaptive collaborative calculation system for power distribution networks according to the present invention. Detailed Implementation

[0057] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0058] Example 1: As Figure 1 As shown, the present invention provides an adaptive collaborative calculation method for multi-level protection settings in a distribution network, comprising:

[0059] S100: parse SVG file and XML file of power distribution line, and construct network topology graph of power distribution line; the SVG file provides connection relationship and hierarchical information of switch node and distribution transformer node, and the XML file provides conductor parameter of feeder section;

[0060] Further, the constructing of the network topology graph of the power distribution line comprises:

[0061] parsing the SVG file, extracting the switch node and the distribution transformer node and their connection relationship, and constructing an initial network graph;

[0062] using a breadth-first search algorithm to calculate the hierarchical information of the root node to each node, the root node level being 0, and the node directly connected with the root node level being 1, and the hierarchical number being increased by 1 for each additional path length;

[0063] checking the hierarchical relationship of each connection edge, retaining the connection with a hierarchical difference of 1, and removing the connection with a hierarchical difference greater than 1, to obtain the SVG topology graph of the power distribution line;

[0064] parsing the XML file, extracting bus section information, switch device information and line section information, establishing electrical connection relationship between devices, and obtaining the XML topology graph of the power distribution line.

[0065] Specifically, first, the SVG file of the power distribution line is parsed, the switch node and the distribution transformer node and their connection relationship are extracted, and an initial network graph object G is constructed. The distribution transformer node includes public transformer and special transformer. In the parsing process, type code is extracted and set for each node in the network graph object G, which is used to distinguish different types of power devices, and the switch node and the distribution transformer node are identified according to the type code.

[0066] Then, the existing switch node and distribution transformer node are screened out from the initial network graph object G, all connection edges between these nodes are extracted, a new network graph object SubG is constructed based on the screened nodes and edges, it is verified whether the generated subgraph is connected, and a connected subgraph SubG containing the switch node and the distribution transformer node after updating is obtained.

[0067] Next, the connected subgraph SubG is subjected to hierarchical analysis and pruning. A breadth-first search (BFS) algorithm is used to calculate the distance from the root node to all nodes, the path length is converted into hierarchical information, and a mapping dictionary of nodes and levels is returned. Among them, the root node level is set to 0, the node directly connected with the root node level is 1, and so on, and the hierarchical number is increased by 1 for each additional path length.

[0068] Based on the hierarchical information, check whether the nodes connected by each edge meet the hierarchical relationship, keep the connections with a hierarchical difference of 1 (i.e. parent-child node connections), and remove the "jump" connections with a hierarchical difference greater than 1 to maintain the main path connectivity from the root node to each leaf node. At the same time, only the connected components containing the root switch node are kept, and isolated devices not connected to the bus are removed to obtain the pruned connected subgraph SubG as the power distribution line SVG topology graph.

[0069] The XML file of the power distribution line is parsed to extract the following device information:

[0070] Bus segment information, including the unique identifier of the bus segment, the name of the bus segment, the voltage level it belongs to, and other attribute information;

[0071] Switch device information, including the unique identifier of the switch, the name of the switch, the type of the switch (circuit breaker, load switch, etc.), rated parameters, and other information;

[0072] Line segment information, including the unique identifier of the line segment, the conductor type, the conductor length, and other information.

[0073] Create a network graph object X, add nodes and edges according to the connection relationship in the XML file, and establish the electrical connection relationship between devices. Only the connected components containing the bus are kept, and isolated devices not connected to the bus are removed to ensure the integrity and effectiveness of the network topology. Add bus type identification to the bus nodes in the network graph object X, add switch type identification to the switch nodes, and add line type identification to the line segment nodes to facilitate the differentiation of different types of devices in subsequent analysis. Finally, the power distribution line XML topology graph X is obtained.

[0074] Through the above steps, the power distribution line SVG topology graph provides the connection relationship and hierarchical information of the switch nodes and distribution transformer nodes, and the power distribution line XML topology graph provides the conductor parameters of the feeder segment. The combination of the two constitutes a complete power distribution line network topology graph, providing basic data for subsequent short-circuit current calculation and protection setting.

[0075] S200: Based on the network topology graph and conductor parameters, calculate the electrical path impedance of each switch node to the root node, combine the system impedance on the power supply side, and calculate the maximum short-circuit current under the maximum operating mode and the minimum short-circuit current under the minimum operating mode of each switch node;

[0076] Further, the calculation of the maximum short-circuit current under the maximum operating mode and the minimum short-circuit current under the minimum operating mode of each switch node includes:

[0077] Calculate the shortest electrical path of each switch node to the root node, and calculate the total resistance and total reactance of the path according to the conductor type and length on the path;

[0078] Adding the total resistance of the path and the total reactance of the path to the resistance component and the reactance component corresponding to the system impedance on the power supply side respectively, total resistance and total reactance from the power supply to each switching node are obtained;

[0079] The total impedance is calculated according to the total resistance and the total reactance;

[0080] The maximum short-circuit current and the minimum short-circuit current of each switching node are calculated based on the total impedance.

[0081] Further, the calculation of the total impedance according to the total resistance and the total reactance comprises:

[0082] In the maximum operating mode, the minimum resistance component of the system impedance on the power supply side is added to the total resistance of the path to obtain the minimum total resistance, and the minimum reactance component of the system impedance on the power supply side is added to the total reactance of the path to obtain the minimum total reactance, and the minimum total impedance is calculated according to the minimum total resistance and the minimum total reactance;

[0083] In the minimum operating mode, the maximum resistance component of the system impedance on the power supply side is added to the total resistance of the path to obtain the maximum total resistance, and the maximum reactance component of the system impedance on the power supply side is added to the total reactance of the path to obtain the maximum total reactance, and the maximum total impedance is calculated according to the maximum total resistance and the maximum total reactance.

[0084] Specifically, in the power distribution line XML topology graph X, the shortest electrical path from each switching node and leaf node to the root node is calculated. According to the wire type and length on the shortest electrical path, the total resistance and the total reactance of the path are calculated. Wherein, the wire type determines the resistance and reactance value per unit length, and the total resistance and total reactance of the path can be calculated by combining the wire length.

[0085] In the calculation of short-circuit current, the influence of different operating modes of the power system on the short-circuit current needs to be considered. The maximum operating mode refers to the operating state of the power system in which the maximum power supply capacity and the minimum system impedance on the power supply side are achieved, for example, multiple main transformers are operated in parallel, multiple tie lines are put into operation, etc., at this time the short-circuit current at the fault point reaches the maximum value; the minimum operating mode refers to the operating state of the power system in which the minimum power supply capacity and the maximum system impedance on the power supply side are achieved, for example, part of the main transformer is shut down, part of the tie line is taken out of operation, etc., at this time the short-circuit current at the fault point reaches the minimum value. In the protection setting calculation, both the maximum and minimum operating modes need to be considered to ensure that the protection device can reliably act (meet the sensitivity requirement) at the minimum short-circuit current and accurately cooperate (meet the selectivity requirement) at the maximum short-circuit current.

[0086] The path total resistance and path total reactance are added to the resistance component and reactance component corresponding to the power supply side system impedance respectively to obtain the total resistance and total reactance from the power supply to each switching node. Since the maximum and minimum operation modes need to be considered, the total impedance in the two operation modes needs to be calculated respectively.

[0087] For the root node, since there is no line impedance, the power supply side system impedance is directly used for calculation.

[0088] In the maximum operation mode, the calculation formula of the total resistance minimum value and the total reactance minimum value is:

[0089] ;

[0090] ;

[0091] In the minimum operation mode, the calculation formula of the total resistance maximum value and the total reactance maximum value is:

[0092] ;

[0093] ;

[0094] wherein, is the maximum value of the equivalent resistance of the power supply side, is the maximum value of the equivalent reactance of the power supply side, is the minimum value of the equivalent resistance of the power supply side, is the minimum value of the equivalent reactance of the power supply side.

[0095] For other switching nodes and leaf nodes, the line impedance needs to be added.

[0096] In the maximum operation mode, the calculation formula of the total resistance minimum value and the total reactance minimum value is:

[0097] ;

[0098] ;

[0099] In the minimum operation mode, the calculation formula of the total resistance maximum value and the total reactance maximum value is:

[0100] ;

[0101] ;

[0102] wherein, and are the path total resistance and total reactance from the node to the root node respectively.

[0103] In the maximum operation mode, the minimum total resistance is obtained by adding the minimum resistance of the system to the total resistance of the path In the maximum operation mode, the minimum total resistance is obtained by adding the minimum resistance of the system to the total resistance of the path The minimum total impedance is calculated according to the minimum total resistance and the minimum total reactance The calculation formula is:

[0104] ;

[0105] In the minimum operation mode, the maximum total resistance is obtained by adding the maximum resistance of the system to the total resistance of the path In the minimum operation mode, the maximum total resistance is obtained by adding the maximum resistance of the system to the total resistance of the path The maximum total impedance is calculated according to the maximum total resistance and the maximum total reactance The calculation formula is:

[0106] ;

[0107] The maximum short-circuit current occurs when the system has the minimum impedance (maximum operation mode), and the calculation formula is:

[0108] ;

[0109] The minimum short-circuit current occurs when the system has the maximum impedance (minimum operation mode), and the calculation formula is:

[0110] ;

[0111] wherein, is the maximum short-circuit current, is the minimum short-circuit current, is the reference voltage, generally 10.5kV.

[0112] Through the above calculation, the maximum short-circuit current and the minimum short-circuit current list of each switch node and leaf node device are obtained, including device name, maximum short-circuit current (three-phase short-circuit current in maximum operation mode), minimum short-circuit current (two-phase short-circuit current in minimum operation mode), etc. The above information provides basic data for subsequent clustering analysis and protection setting calculation.

[0113] S300: using the maximum short-circuit current as the clustering feature, the switch nodes are clustered by using the K-means clustering algorithm; the number of clusters is adaptively determined according to the range of the maximum short-circuit current, and each cluster is sorted and numbered in descending order of the cluster center value;

[0114] Further, the adaptively determining the number of clusters according to the range of the maximum short-circuit current comprises:

[0115] The difference between the maximum value and the minimum value of the maximum short-circuit current of all switch nodes is calculated to obtain a maximum short-circuit current range;

[0116] The maximum short-circuit current range is compared with a preset range threshold, and the corresponding number of clusters is determined according to the threshold interval in which the maximum short-circuit current range is located.

[0117] Specifically, the difference between the maximum value and the minimum value of the maximum short-circuit current of all switch nodes is calculated to obtain a maximum short-circuit current range:

[0118]

[0119] wherein, is the maximum short-circuit current range, is the maximum value of the maximum short-circuit current in all switch nodes, is the minimum value of the maximum short-circuit current in all switch nodes.

[0120] The maximum short-circuit current range is compared with a preset range threshold, and the corresponding number of clusters is determined according to the threshold interval in which the maximum short-circuit current range is located. The number of clusters is determined by using a heuristic rule based on the short-circuit current range:

[0121] When , it is determined that the number of clusters is 1 cluster, indicating that the current difference is small;

[0122] When , it is determined that the number of clusters is 2 clusters, indicating that the current difference is moderate;

[0123] When , it is determined that the number of clusters is 3 clusters, indicating that the current difference is large.

[0124] In this embodiment, the range thresholds 800A and 1500A are typical values determined according to the actual needs of power distribution network protection coordination and engineering experience.

[0125] The maximum short-circuit current value is taken as a clustering feature, and the K-means clustering algorithm is used to cluster the switch nodes and leaf node devices. Random seeds are set to ensure reproducible results, and multiple initializations (such as 10 times) are used to select the optimal clustering center, and each switch node is assigned a cluster number.

[0126] The cluster center values of each cluster are extracted, and each cluster is renumbered in descending order of the cluster center values to ensure that cluster 1 corresponds to the maximum short-circuit current range, cluster 2 corresponds to the moderate short-circuit current range, and cluster 3 corresponds to the minimum short-circuit current range. A mapping relationship between switches and final cluster numbers is established.

[0127] ​Through the above clustering analysis, the switchgears are automatically divided into different levels according to the short-circuit current characteristics, which provides a hierarchical basis for the subsequent hierarchical calculation of protection setting value, and realizes the adaptive configuration of protection level difference.

[0128] S400: Extract the paths from the root node to each leaf node in the network topology graph, group according to the switch combination on the path, and keep the path with the minimum maximum short-circuit current of the leaf node in each group as the representative path;

[0129] Specifically, all leaf nodes in the distribution line SVG topology graph SubG are identified. The leaf node refers to the end node with only one connection edge in the network, which usually corresponds to the end load point or distribution transformer node of the distribution network.

[0130] For each leaf node, the shortest path from the root node to the leaf node is calculated, and all switch node information on the path is extracted to form a path set from the root node to each leaf node. Each path contains the switch node sequence on the path and the short-circuit current information of the corresponding leaf node.

[0131] Convert the switch node list on the path to a string form as the grouping key. For paths with the same switch combination, i.e. paths with the same switch nodes on the path, they are considered as the same class of paths and are grouped.

[0132] For each group of paths with the same switch combination, the maximum short-circuit current value of the leaf node corresponding to each path is obtained, and the path with the minimum maximum short-circuit current of the leaf node in the group is kept as the representative path of the group. This is because in the protection setting value calculation, the minimum short-circuit current determines the sensitivity requirement of the protection device, and selecting the minimum current path can ensure the reliability of the protection configuration.

[0133] All representative paths of the groups are summarized to form a unique path set . This set eliminates redundant paths with the same switch combination and retains the most stringent short-circuit current conditions under each switch combination, providing a simplified and complete analysis object for the subsequent protection setting value calculation.

[0134] Through the above deduplication processing, the number of paths to be processed is significantly reduced under the premise of ensuring the accuracy of the calculation, avoiding repeated calculation, and improving the overall calculation efficiency.

[0135] S500: Identify the main switch on the representative path according to the clustering sorting result; according to the clustering combination in the network, for the main switches of two adjacent levels, calculate the protection setting value of the main switch of the current level based on the maximum short-circuit current of the main switch of the next level and the minimum short-circuit current of the main switch of the current level; for the non-main switches between the two main switches, the protection setting values of the two main switches are used for linear interpolation to obtain the protection setting value of the non-main switch;

[0136] Furthermore, the identification main switch includes:

[0137] Identify the switch at the root node as the root switch;

[0138] When multiple clusters exist, the first switch of each cluster is identified sequentially along the representative path according to the cluster order as the main switch of that cluster.

[0139] Specifically, in representative paths The system identifies the primary switches at each level. The switch at the root node is identified as the root switch, defined as the first-level primary switch. When multiple clusters exist, the first switch of each cluster is identified sequentially along each path according to cluster order, serving as the primary switch for that cluster. This includes identifying the first switch of cluster 2 as the second-level primary switch, and the first switch of cluster 3 as the third-level primary switch. Simultaneously, the system identifies the cluster combination types present in the network. In this embodiment, based on the cluster analysis results, the network may contain the following cluster combinations: a three-level switch system (clusters 1, 2, and 3 all exist), a two-level switch system (clusters 1 and 2 exist), and a two-level switch system (clusters 1 and 3 exist), etc.

[0140] Furthermore, the calculation of the protection settings for the main switch includes:

[0141] Identify the clustering combinations present in the network;

[0142] For the main switches of two adjacent levels, the protection setting value of the main switch of this level is calculated based on the maximum short-circuit current of the next level main switch and the minimum short-circuit current of the main switch of this level.

[0143] For the final stage main switch, its protection setting is calculated based on the maximum and minimum short-circuit currents of the leaf nodes.

[0144] Specifically, based on the clustering and combination in the network, the protection settings for each level of main switches are calculated. The protection settings include overcurrent stage I and overcurrent stage II. The calculation principle is as follows: for two adjacent main switches, the protection settings for the current main switch are calculated based on the maximum short-circuit current of the next-level main switch and the minimum short-circuit current of the current main switch; for the final-level main switch, its protection settings are calculated based on the maximum and minimum short-circuit currents of the leaf nodes.

[0145] In this embodiment, the specific calculation method for different clustering combinations is as follows:

[0146] When the network is a three-level switching system (clusters 1, 2 and 3 exist), first, the protection setting value of the root switch (cluster 1 main switch) is calculated, the overcurrent I section of the root switch is calculated based on the maximum short-circuit current of the first switch of cluster 2 and the minimum short-circuit current of the root switch, and the overcurrent II section of the root switch is calculated based on the maximum short-circuit current of the first switch of cluster 3 and the minimum short-circuit current of the first switch of cluster 2; then, the protection setting value of the cluster 2 main switch is calculated, the overcurrent I section of the cluster 2 main switch is calculated based on the maximum short-circuit current of the first switch of cluster 3 and the minimum short-circuit current of the first switch of cluster 2, and the overcurrent II section of the cluster 2 main switch is calculated based on the maximum short-circuit current of the leaf node and the minimum short-circuit current of the first switch of cluster 3; finally, the protection setting value of the cluster 3 main switch is calculated, and the overcurrent I section and the overcurrent II section of the cluster 3 main switch are both calculated based on the minimum short-circuit current and the maximum short-circuit current of the leaf node.

[0147] When the network is a two-level switching system (clusters 1 and 2 exist), first, the protection setting value of the root switch is calculated, the overcurrent I section of the root switch is calculated based on the maximum short-circuit current of the first switch of cluster 2 and the minimum short-circuit current of the root switch, and the overcurrent II section of the root switch is calculated based on the maximum short-circuit current of the leaf node and the minimum short-circuit current of the first switch of cluster 2; then, the protection setting value of the cluster 2 main switch is calculated, and the overcurrent I section and the overcurrent II section of the cluster 2 main switch are both calculated based on the minimum short-circuit current and the maximum short-circuit current of the leaf node.

[0148] When the network is a two-level switching system (clusters 1 and 3 exist), the overcurrent I section and the overcurrent II section of the root switch are not calculated; the protection setting value of the cluster 3 main switch is calculated, and the overcurrent I section and the overcurrent II section of the cluster 3 main switch are both calculated based on the minimum short-circuit current and the maximum short-circuit current of the leaf node.

[0149] The range of the main switch setting value calculated for each representative path is synthesized to form a main switch setting value range set of the same number. The overcurrent I section setting value takes the maximum value of the upper limit, and the overcurrent II section setting value takes the minimum value of the lower limit, as the final value of the main switch protection setting value. The protection setting values of the first-level main switch, the second-level main switch and the third-level main switch are finally determined.

[0150] Further, the linear interpolation of the protection setting values of the two main switches for the non-main switch between the two main switches comprises:

[0151] identifying the non-main switch between the two adjacent main switches;

[0152] obtaining the protection setting values of the two main switches;

[0153] calculating the protection setting value of the non-main switch based on the protection setting values of the two main switches by using the linear interpolation method according to the position of the non-main switch on the path.

[0154] Specifically, each representative path is segmented, and non-main switches of different segments are identified. The first level non-main switch is the cluster 1 non-first switch between the root switch and the cluster 2 first switch; the second level non-main switch is the cluster 2 non-first switch between the cluster 2 first switch and the cluster 3 first switch; and the third level non-main switch is the cluster 3 non-first switch between the cluster 3 first switch and the leaf node.

[0155] According to different segment and cluster combinations, the protection setting value of the non-main switch is calculated by using the linear interpolation method. Specifically, the non-main switch between two adjacent main switches is identified; the protection setting values of the two end main switches are obtained; and the protection setting value of the non-main switch is calculated by using the linear interpolation method based on the protection setting values of the two end main switches according to the position of the non-main switch on the path.

[0156] In this embodiment, for different cluster combinations, the specific calculation method is as follows:

[0157] When the network is a three-level switch system (clusters 1, 2 and 3 exist), for the first level non-main switch between the first level main switch and the second level main switch, the over-current I section and the over-current II section are linearly interpolated and distributed according to the protection setting values of the first level main switch and the second level main switch; for the second level non-main switch between the second level main switch and the third level main switch, the over-current I section and the over-current II section are linearly interpolated and distributed according to the protection setting values of the second level main switch and the third level main switch; and for the third level non-main switch between the third level main switch and the leaf node, a certain proportion of the short-circuit current of the leaf node is used as the setting value reference.

[0158] When the network is a two-level switch system (clusters 1 and 2 exist), for the first level non-main switch between the first level main switch and the second level main switch, the over-current I section and the over-current II section are linearly interpolated and distributed according to the protection setting values of the first level main switch and the second level main switch; and for the second level non-main switch between the second level main switch and the leaf node, a certain proportion of the short-circuit current of the leaf node is used as the setting value reference.

[0159] When the network is a two-level switch system (clusters 1 and 3 exist), for the first level non-main switch between the first level main switch and the third level main switch, the over-current I section and the over-current II section are linearly interpolated and distributed according to the protection setting values of the first level main switch and the third level main switch; and for the third level non-main switch between the third level main switch and the leaf node, a certain proportion of the short-circuit current of the leaf node is used as the setting value reference.

[0160] The calculation formula of the linear interpolation is:

[0161] ;

[0162] wherein, is the protection setting value of the non-main switch, is the protection setting value of the upper main switch, is the protection setting value of the lower main switch, is the distance from the non-main switch to the upper main switch, is the total distance between the two main switches. The distance can be expressed in hierarchical number or electrical distance. By linear interpolation method, the smooth transition and reasonable coordination of the protection setting values between adjacent switches are ensured, and the problems of protection dead zone and step-out tripping are avoided.

[0163] S600: output the protection setting value table of all switches.

[0164] Further, the output of the protection setting value table of all switches includes:

[0165] integrating the protection setting values of the main switches at each level;

[0166] integrating the protection setting values of the non-main switches between the main switches;

[0167] forming a protection setting value table containing switch names and protection setting values.

[0168] Specifically, this step integrates the protection setting values of all switches in the distribution line, forms a complete protection setting value table and outputs it, which is convenient for subsequent analysis and application.

[0169] Specifically, the output of the protection setting value table of all switches includes the following steps:

[0170] First, integrate the protection setting values of the main switches at each level, including the overcurrent I section and overcurrent II section protection setting values of the root switch, cluster 2 main switch, cluster 3 main switch, etc.; then, integrate the protection setting values of the non-main switches between the main switches, including the overcurrent I section and overcurrent II section protection setting values of the non-main switches at each level; finally, the protection setting values of the main switches and the non-main switches are summarized to form a complete protection setting value table containing switch names and protection setting values. The protection setting value table covers all switch devices in the distribution line, providing complete data support for protection device setting and configuration.

[0171] Through the above steps S100 to S600, the present application realizes the full-flow automation of the multi-level protection setting value calculation of the distribution network, from topology modeling, short-circuit current calculation, intelligent clustering analysis, path optimization, setting value hierarchical calculation to result output, forming a complete technical solution, effectively solving the problems of complex calculation, insufficient precision and poor adaptability of traditional methods.

[0172] Embodiment two: as shown in the embodiment, the present application provides a multi-level protection setting value adaptive collaborative calculation system for distribution network, which comprises: Figure 2 ​

[0173] A topology construction module is configured to parse SVG files and XML files of the power distribution line and construct a power distribution line network topology graph; the SVG files provide connection relationships and hierarchical information of switch nodes and distribution node, and the XML files provide conductor parameters of feeder sections;

[0174] A short-circuit calculation module is configured to calculate electrical path impedance of each switch node to the root node based on the network topology graph and the conductor parameters, and calculate maximum short-circuit current of each switch node in a maximum operation mode and minimum short-circuit current of each switch node in a minimum operation mode in combination with system impedance on the power supply side;

[0175] An intelligent clustering module is configured to cluster the switch nodes by taking the maximum short-circuit current as a clustering feature and using a K-means clustering algorithm; the number of clusters is adaptively determined according to the range of the maximum short-circuit current, and each cluster is sorted and numbered in descending order of the cluster center value;

[0176] A path optimization module is configured to extract paths from the root node to each leaf node in the network topology graph, group the paths according to switch combinations on the paths, and reserve a path with minimum maximum short-circuit current of leaf nodes as a representative path for each group;

[0177] A setting calculation module is configured to identify main switches according to the clustering sorting results on the representative paths; according to the clustering combination in the network, for main switches of two adjacent levels, the protection setting value of the main switch of the current level is calculated based on the maximum short-circuit current of the main switch of the next level and the minimum short-circuit current of the main switch of the current level; for non-main switches between two main switches, the protection setting values of the two main switches are linearly interpolated to obtain the protection setting value of the non-main switch;

[0178] A result output module is configured to output a protection setting value table of all switches.

[0179] It should be noted that the power distribution network multi-level protection setting adaptive collaborative calculation system provided by the embodiments of the present application is used to execute all process steps of the power distribution network multi-level protection setting adaptive collaborative calculation method of the above-mentioned embodiment one, and the working principles and beneficial effects of the two are one-to-one corresponding, thus it is not repeated here.

[0180] Through the collaborative work of each module, the system realizes the full-process automation of the protection setting calculation of the distribution network. Compared with the traditional manual calculation method, the system has the following obvious advantages: first, the intelligent clustering technology is used to realize adaptive configuration of protection level difference, which can flexibly adjust the protection level according to the actual short-circuit current distribution of the network; second, the path optimization and linear interpolation technology are used to greatly improve the calculation efficiency under the premise of ensuring the calculation accuracy; third, the full-process automation from topology construction to result output is realized, which greatly reduces the manual intervention; fourth, the system has strong adaptive ability and can quickly respond to network structure changes and operation mode adjustments. The system provides an automatic and intelligent technical solution for the protection setting calculation of the distribution network, effectively solving the problems of low efficiency, easy errors and difficulty in adapting to complex networks of the traditional method.

[0181] Finally, it should be noted that: the above only for the preferred embodiments of the present application, and not for limiting the present application, although the foregoing embodiments of the present application are described in detail, for those skilled in the art, it still can be modified, or part of the technical features of the equivalent replacement. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method for adaptive collaborative calculation of multi-level protection settings in a distribution network, characterized in that, include: S100: Parses the SVG and XML files of power distribution lines to construct a power distribution line network topology diagram; The SVG file provides the connection relationship and hierarchy information of the switch nodes and distribution transformer nodes, and the XML file provides the conductor parameters of the feeder segment; S200: Based on the network topology and conductor parameters, calculate the electrical path impedance from each switch node to the root node, and combine it with the power supply system impedance to calculate the maximum short-circuit current of each switch node under the maximum operating mode and the minimum short-circuit current under the minimum operating mode. S300: Using the maximum short-circuit current as the clustering feature, the K-means clustering algorithm is used to cluster the switching nodes; The number of clusters is adaptively determined based on the range of the maximum short-circuit current, and each cluster is sorted and numbered from largest to smallest according to its cluster center value. S400: Extract the path from the root node to each leaf node in the network topology graph, group them according to the switch combination on the path, and retain the path with the minimum maximum short-circuit current of the leaf node in each group as the representative path. S500: Identify the main switches on representative paths based on clustering results; based on the clustering combination in the network, for two adjacent main switches, calculate the protection setting of the main switch based on the maximum short-circuit current of the next-level main switch and the minimum short-circuit current of the main switch at this level; for non-main switches between two main switches, use the protection settings of the two main switches to perform linear interpolation to obtain the protection setting of the non-main switches. S600: Outputs the protection setting table for all switches.

2. The adaptive collaborative calculation method for multi-level protection settings in a distribution network according to claim 1, characterized in that, The construction of the power distribution line network topology includes: Parse the SVG file, extract the switch nodes and transformer nodes and their connection relationships, and construct the initial network diagram; The breadth-first search algorithm is used to calculate the level information from the root node to each node. The level of the root node is 0, the level of the node directly connected to the root node is 1, and the level number is increased by 1 for each additional path length. Check the hierarchical relationship of each connection edge, keep the connection with a hierarchical difference of 1, and remove the connection with a hierarchical difference greater than 1 to obtain the SVG topology diagram of the power distribution line; Parse the XML file to extract busbar segment information, switchgear information, and line segment information, establish the electrical connection relationships between the equipment, and obtain the XML topology diagram of the power distribution line.

3. The adaptive collaborative calculation method for multi-level protection settings in a distribution network according to claim 1, characterized in that, The calculation of the maximum short-circuit current of each switching node under the maximum operating mode and the minimum operating mode includes: Calculate the shortest electrical path from each switching node to the root node, and calculate the total resistance and total reactance of the path based on the type and length of the wires on the path. Add the total path resistance and total path reactance to the resistance and reactance components corresponding to the system impedance on the power supply side, respectively, to obtain the total resistance and total reactance from the power supply to each switching node; Calculate the total impedance based on the total resistance and total reactance; The maximum and minimum short-circuit currents of each switching node are calculated based on the total impedance.

4. The adaptive collaborative calculation method for multi-level protection settings in a distribution network according to claim 3, characterized in that, The calculation of total impedance based on total resistance and total reactance includes: Under maximum operating conditions, the minimum resistance component of the power supply system impedance is added to the total path resistance to obtain the minimum total resistance, and the minimum reactance component of the power supply system impedance is added to the total path reactance to obtain the minimum total reactance. The minimum total impedance is calculated based on the minimum total resistance and the minimum total reactance. In the minimum operating mode, the maximum resistance component of the power supply system impedance is added to the total path resistance to obtain the maximum total resistance, and the maximum reactance component of the power supply system impedance is added to the total path reactance to obtain the maximum total reactance. The maximum total impedance is calculated based on the maximum total resistance and the maximum total reactance.

5. The adaptive collaborative calculation method for multi-level protection settings in a distribution network according to claim 1, characterized in that, The adaptive determination of the number of clusters based on the range of the maximum short-circuit current includes: Calculate the difference between the maximum and minimum values ​​of the maximum short-circuit current for all switching nodes to obtain the range of the maximum short-circuit current; The maximum short-circuit current range is compared with a preset range threshold, and the corresponding number of clusters is determined based on the threshold interval in which the maximum short-circuit current range is located.

6. The adaptive collaborative calculation method for multi-level protection settings in a distribution network according to claim 1, characterized in that, The main identification switch includes: Identify the switch at the root node as the root switch; When multiple clusters exist, the first switch of each cluster is identified sequentially along the representative path according to the cluster order as the main switch of that cluster.

7. The adaptive collaborative calculation method for multi-level protection settings in a distribution network according to claim 6, characterized in that, The calculation of the protection settings for the main switch includes: Identify the clustering combinations present in the network; For the main switches of two adjacent levels, the protection setting value of the main switch of this level is calculated based on the maximum short-circuit current of the next level main switch and the minimum short-circuit current of the main switch of this level. For the final stage main switch, its protection setting is calculated based on the maximum and minimum short-circuit currents of the leaf nodes.

8. The adaptive collaborative calculation method for multi-level protection settings in a distribution network according to claim 1, characterized in that, The linear interpolation of the non-main switches between the two main switches using the protection settings of the main switches at both ends includes: Identify the non-primary switches between two adjacent primary switches; Obtain the protection settings of the main switches at both ends; Based on the location of the non-main switch on the path, the protection setting of the non-main switch is calculated using a linear interpolation method based on the protection setting of the main switches at both ends.

9. The adaptive collaborative calculation method for multi-level protection settings in a distribution network according to claim 1, characterized in that, The protection setting table for all output switches includes: Integrate the protection settings of major switches at all levels; Integrate the protection settings of non-main switches among the main switches; Create a protection setting table that includes switch names and protection settings.

10. A multi-level protection setting adaptive collaborative calculation system for a distribution network, characterized in that, include: The topology building module is used to parse SVG and XML files of power distribution lines and build a power distribution line network topology diagram. The SVG file provides the connection relationship and hierarchy information of the switch nodes and distribution transformer nodes, and the XML file provides the conductor parameters of the feeder segment; The short-circuit calculation module is used to calculate the electrical path impedance from each switch node to the root node based on the network topology and conductor parameters, and to calculate the maximum short-circuit current of each switch node under the maximum operating mode and the minimum short-circuit current under the minimum operating mode in combination with the power supply system impedance. The intelligent clustering module is used to cluster switching nodes using the maximum short-circuit current as the clustering feature and the K-means clustering algorithm. The number of clusters is adaptively determined based on the range of the maximum short-circuit current, and each cluster is sorted and numbered from largest to smallest according to its cluster center value. The path optimization module is used to extract paths from the root node to each leaf node in the network topology graph, group them according to the switch combinations on the path, and retain the path with the minimum maximum short-circuit current of the leaf node in each group as the representative path. The setting calculation module is used to identify the main switches on representative paths based on the clustering results; based on the clustering combination in the network, for two adjacent main switches, the protection setting of the main switch at this level is calculated based on the maximum short-circuit current of the next-level main switch and the minimum short-circuit current of the main switch at this level; for non-main switches between two main switches, the protection setting of the non-main switches is obtained by linear interpolation using the protection setting of the two main switches. The result output module is used to output the protection setting table for all switches.

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