Network-related fault calculation and constant value checking method based on graph database

Abstract

The invention relates to the technical field of relay protection, in particular to a graph database-based network-related fault calculation and constant value checking method, which comprises the following steps of: S1, acquiring power plant station in-operation data, and performing classification, format conversion and analysis to form a data set and a constant value library; s2, constructing a graph database model based on the in-operation data of the power plant station; s3, based on the graph database model, topological connection constraints and power equipment impedance parameters required by fault calculation are extracted, a structured calculation data source is formed, and fault current of a fault point and associated equipment is calculated; s4, based on the expert rule base and the fault current, performing multi-dimensional matching verification on the structured constant value data, and generating a verification conclusion; and S5, performing visual output. According to the invention, the construction of the static topological structure of the plant station and the overall verification of the constant value sensitivity and the cooperation logic are realized, and the accuracy, efficiency and intelligent level of the relay protection network-related constant value verification work are obviously improved.

Description

Technical Field

[0001] This invention relates to the field of relay protection technology, specifically to a method for calculating and verifying network faults based on graph databases. Background Technology

[0002] In power plants and substations, the setting of relay protection devices needs to ensure four characteristics: reliability, selectivity, sensitivity, and speed. Among them, selectivity requires that in the event of a fault, only the protection closest to the fault point should operate to clear the fault, so as to ensure continuous power supply to the non-faulty parts. This depends on the strict logical coordination between the settings of protection at each level, such as between the main transformer protection and the outgoing line protection, and between the collector line protection and the transformer substation protection.

[0003] Currently, the analysis of the logical coordination between protection measures mainly relies on manual methods.

[0004] 1. Manual Review: Technicians need to manually read electrical main wiring diagrams, protection configuration lists, and other documents, relying on experience to mentally construct logical coordination diagrams for protection devices. For complex new energy power plants (containing numerous wind turbines / photovoltaic units, transformer substations, collector lines, main transformers, etc.), this process is tedious, time-consuming, and prone to errors or omissions.

[0005] 2. Static verification: Existing setpoint verification systems mostly focus on verifying whether a single setpoint exceeds the limit, or rely on preset, fixed coordination rules. They cannot dynamically and intuitively display the coordination relationship of the entire protection network and lack a holistic verification of the coordination logic of the entire protection system.

[0006] 3. Low efficiency: Manually sorting out the coordination relationship has become a bottleneck in the setting and verification work, making it difficult to adapt to the needs of frequent changes in the power grid structure and the rapid commissioning of new energy power plants.

[0007] Therefore, there is an urgent need for a technical means that can automatically, accurately, and intuitively generate and analyze protection coordination relationships and perform intelligent verification. Summary of the Invention

[0008] To address the technical problem that existing methods for analyzing the logical coordination relationships between relay protection systems mainly rely on manual methods and can only perform single-value over-limit verification, this invention provides a graph database-based method for calculating network-related faults and verifying settings. This method realizes the overall verification of the static topology structure of the substation, setting sensitivity, and coordination logic, significantly improving the accuracy, efficiency, and intelligence level of relay protection network-related setting verification.

[0009] The technical solution adopted in this invention is to provide a method for network fault calculation and setting verification based on graph database, including the following steps:

[0010] S1. Obtain power plant operation data, including power equipment information, setting information and power topology, and classify, convert and parse the data to form a dataset and setting library;

[0011] S2. Construct a graph database model based on the power plant operation data;

[0012] S3. Based on the graph database model, extract the topological connection constraints and power equipment impedance parameters required for fault calculation, form a structured calculation data source, calculate the fault current of the fault point and related equipment, and generate a fault bus current table for each voltage level.

[0013] S4. Based on the expert rule base and fault current, perform multi-dimensional verification of structured setting data and generate verification conclusions.

[0014] S5. Visual output: Outputs a static topology diagram with labeled fault current, a comparison table of currents for multiple fault types, an equivalent circuit diagram of the impedance network, and the result of setting verification.

[0015] The parsing in step S1 specifically includes,

[0016] Power equipment information parsing, based on a pre-built equipment parameter template library, uses natural language processing and keyword matching algorithms to locate and extract key information of power equipment from the parsed text, including nameplate parameters, impedance parameters and CT / PT ratio information;

[0017] Setting information parsing: Through table recognition technology and setting item semantic understanding model, information is identified and extracted from relay protection setting sheets and calculation sheets to form a structured setting list;

[0018] Power topology analysis involves parsing a primary wiring diagram and using image recognition and topology analysis algorithms to locate the coordinates of equipment and connecting segments in the primary wiring diagram, identify the connection relationships of electrical equipment within the site, and form a resolvable network topology data source.

[0019] Step S2, which involves constructing the graph database model, specifically includes:

[0020] S21. Based on the Neo4j tag attribute graph model, design a graph database model framework for the connection relationships of plant equipment, including:

[0021] Each node has a unique ID and attributes, representing the power equipment in the plant.

[0022] Relationships, the relationships between nodes, are directional and represent the physical connections or logical associations between nodes;

[0023] S22. Construct a static topology, including:

[0024] Nodes are constructed, converting each power device into a node representation in a graph database model, with each node having a unique ID and attributes;

[0025] Establish relationships by establishing connections between corresponding nodes based on the physical connections between power equipment and the protection configuration.

[0026] Virtual nodes are used to represent T-connections and branch points.

[0027] Step S3 involves extracting the topology connectivity constraints and power equipment impedance parameters required for fault calculation.

[0028] S31. Locate the target faulty bus from the graph database model, traverse all its associated primary devices through depth-first search, and output a local topology subgraph with the target faulty bus as the core.

[0029] S32. Extract the power equipment impedance parameters from the node attributes of the graph database model, calculate the sequence impedance using the per-unit method, and generate a per-unit parameter table of the sequence impedance for each power equipment.

[0030] S33. Based on the fault type, the power equipment sequence impedance of the local topology subgraph is spliced ​​with the equivalent sequence impedance of the external system in a static connection relationship to generate the corresponding sequence network impedance network.

[0031] The calculation of the fault current of the fault point and related equipment in step S3 specifically includes,

[0032] S34. Calculation of symmetrical fault current at the fault point, the expression is as follows.

[0033]

[0034] In the formula, E represents the three-phase short-circuit current. eq Z represents the equivalent electromotive force. total1 Indicates the positive-sequence total impedance;

[0035] S35. Calculation of asymmetrical fault current at the fault point, the expression is as follows.

[0036] Sequence current,

[0037] Phase current, I A =3I1,I B =I C =0

[0038] In the formula, I1 represents the positive sequence current, I2 represents the negative sequence current, I0 represents the zero sequence current, and I... A I represents the phase A current. B I represents the phase B current. C E represents the C-phase current.eq represents the equivalent electromotive force, Z total1 represents the positive-sequence total impedance, Z total2 represents the negative-sequence total impedance, Z total0 represents the zero-sequence total impedance;

[0039] S36. For the upstream and downstream devices associated with the fault point, use the connection relationship matrix of the static topology to determine the current conduction path, and calculate the fault current of the associated devices through impedance voltage division and ratio conversion. The expression is as follows:

[0040]

[0041] In the formula, I nodei represents the fault current of the associated node, represents the three-phase short-circuit current, Z total1 represents the positive-sequence total impedance, Z i represents the impedance from node i to the fault point, Z total-i represents the remaining network impedance.

[0042] In step S4, the multi-dimensional coordination check specifically includes:

[0043] S41. Based on the static topology connection relationship and protection configuration relationship of the graph database model, locate the set of associated protection devices that have coordination requirements with the target protection device, and construct a protection coordination link;

[0044] S42. Extract the setting parameters of all protection devices in the protection coordination link from the setting value library and the graph database model, perform structured integration and consistency check, eliminate data format differences, and output a structured setting value dataset;

[0045] S43. Substitute the checking principle to perform time limit coordination check, current setting value coordination check and sensitivity check, and output the checking result and calculation book.

[0046] In step S43, the time limit coordination check, current setting value coordination check and sensitivity check specifically include:

[0047] Time limit coordination check, the expression is as follows:

[0048] Δt actual =t set1 -t set2

[0049] In the formula, Δt actual represents the time difference between the upstream and downstream protection action time limits, t set1 represents the action time limit of the target protection, t set2 represents the action time limit of the protection associated with the target; if Δt actual ≥0.5s, it is qualified;

[0050] Current setting coordination verification, the expression is as follows,

[0051]

[0052] K actual represents the coordination coefficient of the primary and secondary protections, I set1 represents the fault current of the target protection, I set1 represents the fault current of the protection associated with the target; if K actual ≥1.2, it is qualified;

[0053] Sensitivity verification, the expression is as follows,

[0054]

[0055] K s_actual represents the protection sensitivity coefficient, I dmin represents the minimum value of the fault current of the target protection, I set represents the setting value of the target protection; if K s_actual ≥1.5, it is qualified.

[0056] The beneficial effects of the present invention are as follows

[0057] 1. The data management is more standardized. The scattered data such as substation setting sheets, calculation sheets, and primary wiring diagrams on site are integrated to form a unified original data set and setting value library, avoiding scattered and chaotic data, and providing a reliable and unified data basis for subsequent verification.

[0058] 2. The topological expression is more complete and clear. The node - relationship model of the graph database is used to realize the node - based representation of power equipment and connection relationships. Virtual nodes are introduced to process special structures such as T - connected lines, ensuring the integrity of the topological structure of the generator - transformer unit part in the power plant, and the device association relationships are intuitive and easy to understand, facilitating quick positioning of equipment and protection devices.

[0059] 3. The verification efficiency and accuracy are improved. Relying on the relationship query ability of the graph database, after confirming the protection equipment and setting value items to be verified, other protection equipment associated with the equipment to be verified and the corresponding setting value data can be quickly located. Considering the coordination logic of the protection equipment to be verified and its associated protection equipment, and combining with the verification rules for overall verification, the efficiency and accuracy of network - related setting value verification are greatly improved, reducing the cumbersome operations of manual search and reducing human errors.

[0060] 4. More accurate sensitivity verification: Based on the static topology and standardized impedance parameters in the graph database, the fault current calculation process of fault points and their associated protection devices is carried out through "static topology extraction - impedance mapping - sequence network splicing - matrix solving". This enables the calculation of fault current for multiple fault types and multiple nodes. Combined with the per-unit method and equivalent modeling of external systems, the calculation error can be controlled within 3%. It also supports the calculation of fault current conduction along the topology path, providing more accurate and reasonable fault current data for protection setting verification.

[0061] 5. Output of results is more convenient, and verification calculation sheets can be automatically generated, eliminating the need to manually organize the verification process and results, simplifying the subsequent archiving and usage process, and improving work convenience. Attached Figure Description

[0062] Figure 1 This is a flowchart of the method of the present invention. Detailed Implementation

[0063] like Figure 1 As shown, this invention provides a method for network fault calculation and setting verification based on graph database, including the following steps:

[0064] S1. Data Acquisition and Preprocessing

[0065] Acquire operational data from power plants, including power equipment information, setting information, and power topology relationships, such as nodes like "220kV bus, 110kV bus, generator, main transformer, 110kV line 01" and their connection relationships, as well as the configuration and setting values ​​of protection devices for each primary equipment; and perform classification, format conversion, and parsing to form datasets and setting value libraries;

[0066] Power equipment information parsing, based on a pre-built equipment parameter template library, uses natural language processing and keyword matching algorithms to locate and extract key information of power equipment from the parsed text, including nameplate parameters, impedance parameters and CT / PT ratio information;

[0067] Setting information parsing: Through table recognition technology and setting item semantic understanding model, information is identified and extracted from relay protection setting sheets and calculation sheets to form a structured setting list;

[0068] Power topology analysis involves parsing a primary wiring diagram and using image recognition and topology analysis algorithms to locate the coordinates of equipment and connecting segments in the primary wiring diagram, identify the connection relationships of electrical equipment within the site, and form a resolvable network topology data source.

[0069] S2. Construct a graph database model based on the power plant operation data;

[0070] S21. Construct a graph database model framework

[0071] Based on the Neo4j tag attribute graph model, a graph database model framework for power plant equipment and their connections is constructed, including:

[0072] Nodes represent various primary and secondary equipment in a power plant, such as transformers, circuit breakers, busbars, lines, and protection devices. Each node has a unique ID and attributes, such as equipment name, equipment type, equipment parameters, and protection settings.

[0073] Relationships represent the relationships between nodes, such as being connected to or configured with; relationships are directional and are used to describe the physical connections or logical associations between nodes.

[0074] Node type definition:

[0075] Different node types are defined based on the type of plant equipment and protection devices:

[0076] Transformer node refers to the transformer equipment in a power plant;

[0077] Circuit breaker node indicates the circuit breaker equipment in a power plant;

[0078] Busbar node refers to the busbar equipment in a power plant;

[0079] Line nodes represent outgoing line equipment in a power plant;

[0080] Generator nodes represent generator equipment in a power plant;

[0081] The protection device node represents the protection devices in the power plant.

[0082] Relation type definition:

[0083] Define different relationship types based on the relationships between nodes:

[0084] CONNECT_TO, meaning connected to, indicates the physical connection between two devices, such as a circuit breaker connected to a busbar;

[0085] PROTECT_TO, which is configured to, represents the relationship between the protection device and the equipment it protects.

[0086] S22. Construct a static topology.

[0087] Based on the primary wiring diagram and equipment parameters, the static topology of the plant is constructed, including:

[0088] Establish nodes to convert each power device into a node representation in a graph database model, with each node having a unique ID and attributes;

[0089] Establish relationships between corresponding nodes based on the physical connections and protection configurations of the power equipment. For example, if a circuit breaker is connected to the busbar, a CONNECT_TO relationship is established between the circuit breaker node and the busbar node. If a transformer is equipped with a DGT-801U protection device, a PROTECT_TO relationship is established between the transformer node and the protection device node.

[0090] Virtual nodes are introduced to represent special structures such as T-connections and branch points, ensuring the integrity of the topology.

[0091] S3, Fault Current Calculation

[0092] Based on the graph database model, the topological connection constraints and power equipment impedance parameters required for fault calculation are extracted to form a structured calculation data source and calculate the fault current of the fault point and related equipment, generating a fault bus current table for each voltage level.

[0093] S31, Static Topology Data Extraction

[0094] Locate the target voltage level fault bus, i.e., the fault point, from the graph database model. Use depth-first search to traverse all associated primary equipment, including upstream and downstream transformers, connecting lines, generators, and loads, and output a local topology subgraph centered on the target fault bus; the following is an example.

[0095] enter,

[0096] fault_bus_id: ID of the faulty bus node;

[0097] voltage_level: Target voltage level, such as 110kV, 220kV;

[0098] graph_db: A static topology graph database containing node attributes and CONNECT_TO relationships.

[0099] Output,

[0100] local_topology_subgraph: Local topology subgraph, containing a set of nodes V = {device node IDs} and a set of edges E = {connection relationships};

[0101] connection_matrix: Connection matrix, A∈R^(n×n), A [i][j] =1 indicates that devices i and j are directly connected, 0 indicates that they are not connected, and n is the number of devices in the local topology subgraph.

[0102] S32, Impedance Parameter Mapping for Multiple Equipment Types

[0103] The impedance parameters of power equipment are extracted from the node attributes of the graph database model, and the sequence impedance is calculated using the per-unit method to generate a table of per-unit sequence impedance parameters for each power equipment; the following is an example.

[0104] enter,

[0105] Circuit: Extract the positive sequence resistance of R1, the positive sequence reactance of X1, the zero sequence resistance of R0, and the zero sequence reactance of X0, and map them from the analytical data based on the conductor type and length;

[0106] Transformer: Extracting U k % short-circuit voltage percentage, P k Short-circuit loss, converted to positive-sequence impedance Zero-sequence impedance Z T0 Adjust according to the wiring group, such as zero-sequence impedance ≈ Z for YNd11 wiring. T1 ;

[0107] Generator: Extract X″ d Subtransient reactance, X2 negative sequence reactance, X0 zero sequence reactance;

[0108] Load: Simplified to a constant impedance model. S L Rated apparent power, The power factor.

[0109] Output,

[0110] impedance_table: A table of per-unit impedance parameters, including device node ID, Z1 positive sequence impedance per-unit value, Z2 negative sequence impedance per-unit value, and Z0 zero sequence impedance per-unit value.

[0111] S33. Based on the fault type, such as three-phase short circuit or single-phase grounding, the device sequence impedance of the local topology subgraph is spliced ​​with the equivalent sequence impedance of the external system according to the static connection relationship to generate the impedance network of the corresponding sequence network; the following is an example.

[0112] Three-phase short circuit, i.e., symmetrical fault: only a positive sequence network is needed, and the splicing logic is Z. total1 =Z local1 +Z eq1 In the formula, Z local1 For local topological positive sequence impedance series / parallel combinations, calculations are based on onnection_matrix;

[0113] A single-phase ground fault, i.e., an asymmetrical fault, requires a series connection of positive-sequence, negative-sequence, and zero-sequence networks. total =Z total1 +Z total2 +Z total0 In the formula, Z total1 Z is the positive-sequence total impedance.total2 For the negative sequence total impedance, Z total0 This is the zero-sequence total impedance.

[0114] S34. Calculation of symmetrical fault current at the fault point, the expression is as follows.

[0115]

[0116] In the formula, E represents the three-phase short-circuit current. eq Z represents the equivalent electromotive force. total1 Indicates the positive-sequence total impedance;

[0117] S35. Calculation of asymmetrical fault current at the fault point, the expression is as follows.

[0118] Sequence current,

[0119] Phase current, I A =3I1,I B =I C =0

[0120] In the formula, I1 represents the positive sequence current, I2 represents the negative sequence current, I0 represents the zero sequence current, and I... A I represents the phase A current. B I represents the phase B current. C E represents the C-phase current. eq Z represents the equivalent electromotive force. total1 Z represents the positive-sequence total impedance. total2 Z represents the negative sequence total impedance. total0 Represents the zero-sequence total impedance;

[0121] S36. Calculation of Fault Current Conduction in Multiple Nodes

[0122] For upstream and downstream equipment associated with a faulty bus, such as the high-voltage and low-voltage sides of a transformer, the current conduction path is determined using the static topology connection matrix (connection_matrix). The fault current of the associated equipment is calculated using impedance voltage division and turns ratio calculation, as shown in the following expression.

[0123]

[0124] In the formula, I nodei This represents the fault current of the associated node. Z represents the three-phase short-circuit current. total1 Z represents the positive-sequence total impedance. i Z represents the impedance from node i to the fault point. total-i This represents the remaining network impedance.

[0125] S37. Generate fault bus current meters for each voltage level.

[0126] S4, Network-related Fixed Value Verification

[0127] Based on the expert rule base for relay protection setting verification and the fault current calculated based on the graph data model, the structured setting data is verified in multiple dimensions, and verification conclusions are generated.

[0128] S41, Location of Topology Association Protection Device

[0129] Based on the static topology connection relationship and protection configuration relationship of the graph database model, the set of associated protection devices that have cooperation requirements with the target protection device is located, and the protection cooperation link is constructed; the following is an example.

[0130] enter,

[0131] target_protection_id: Target protection device node ID, such as the ID of the main transformer zero-sequence overcurrent protection device;

[0132] protection_type: The protection type to be verified, such as zero-sequence overcurrent protection;

[0133] graph_db: A static topology graph database containing node attributes and CONNECT_TO / PROTECT_TO relationships;

[0134] search_depth: Topology search depth, defaults to 3 layers, to avoid excessive traversal of unrelated devices.

[0135] calculate,

[0136] Starting from target_protection_id, the core device it protects is located in reverse through the PROTECT_TO relationship, such as transformer node T1;

[0137] Starting from the core equipment, perform a bidirectional breadth-first search along the CONNECT_TO relationship to traverse all downstream devices of the physical connection, such as bus B1 → circuit breaker CB1 → line L1.

[0138] For the downstream devices that are traversed, the same type of protection devices are filtered out through the PROTECT_TO relationship, such as the zero-sequence overcurrent protection device P2 of line L1, to form a set of associated protection devices.

[0139] Output protection coordination link: [Target protection device → Associated protection device 0] → [Connecting device 1 → Associated protection device 1] → [Connecting device 2 → Associated protection device 2]...

[0140] Output,

[0141] protection_coordination_chain: Protection coordination chain, including device connection path, associated protection device ID and device information;

[0142] S42, Multi-source fixed-value data mapping

[0143] The setpoint parameters of all protection devices in the protection coordination link are extracted from the setpoint library and graph database model, and then structured integration and consistency verification are performed to eliminate data format differences and output a structured setpoint dataset; the following is an example.

[0144] enter,

[0145] protection_coordination_chain: The coordinating link output by the topology-associative protection device positioning function;

[0146] setting_database: Standard setting database, containing protection device ID, setting item name, setting value, unit, and version number;

[0147] parameter_template: Protection setting parameter template, defined by type, including required fields, such as zero-sequence overcurrent protection requiring operating current I. set Action time limit t set .

[0148] Calculation logic:

[0149] Based on the protection device ID in the coordinated link, the corresponding setting item is extracted from the setting_database, such as the I value of target protection P1. set1 =5A, t set1 =1.2s; I of associated protection P2 set2 =3A, t set2 =0.5s;

[0150] An NLP semantic alignment algorithm is used to unify the names of heterogeneous setting terms, such as mapping the zero-sequence overcurrent stage operating current and the zero-current stage I setting to I. set ;

[0151] Output,

[0152] structured_setting_dataset: A structured setting dataset containing protection equipment, protection device IDs, and I... set t set Standardized parameters;

[0153] S43. Protection Coordination Rule Matching and Verification

[0154] Based on the expert rule base for relay protection settings, the time-limit coordination verification, current setting coordination verification, and sensitivity verification are performed by substituting the verification principles, and the verification results and calculation sheets are output; the following is an example.

[0155] Input parameters:

[0156] structured_setting_dataset: The structured dataset output by the intelligent mapping function for multi-source fixed-value data;

[0157] expert_rule_base: Expert verification rule base, storing coordination rules according to protection type, such as zero-order overcurrent protection rule set;

[0158] Processing logic,

[0159] Time-limit coordination verification rule: The time limit difference between upper and lower level protection actions Δt = t up -t down ≥0.5s, the upper level is target protection, and the lower level is associated protection;

[0160] Verification: ΔK actual =t set1 -t set2 ;

[0161] In the formula, Δt actual t represents the time difference between upper and lower level protection actions. set1 The time limit for target protection action, t set2 Indicates the duration of the action associated with the target protection; if Δt actual If the time is ≥0.5s, it is considered acceptable; otherwise, it is marked as insufficient time limit difference.

[0162] Current setting coordination verification, rule: coordination coefficient between higher and lower level settings.

[0163] check,

[0164] In the formula, K actual I represents the coordination coefficient between upper and lower level protection systems. set1 I represents the fault current of the target protection. set1 This represents the fault current associated with the target protection; if K actual If the value is ≥1.2, it is considered acceptable; otherwise, it is marked as insufficient matching coefficient.

[0165] Sensitivity verification rule: Protect the sensitivity coefficient

[0166] In the formula, I dmin To obtain the minimum fault current, retrieve the fault current calculation results;

[0167] check,

[0168] In the formula, K s_actual I represents the protection sensitivity coefficient. dmin I represents the minimum fault current of the target protection. set This represents the setpoint for target protection; if K s_actual A value of ≥1.5 is considered acceptable; otherwise, it is marked as a failure to meet sensitivity requirements.

[0169] Output,

[0170] calibration_result: The calibration result set, containing the calibration results for each rule;

[0171] S5, Visual Output

[0172] The system displays and outputs a static topology diagram with labeled fault currents, a comparison table of currents for multiple fault types, an equivalent circuit diagram of the impedance network, and the results of setting verification through a graphical interface.

Claims

1. A method for network fault calculation and setting verification based on graph database, characterized in that: Includes the following steps, S1. Obtain power plant operation data, including power equipment information, setting information and power topology, and classify, convert and parse the data to form a dataset and setting library; S2. Construct a graph database model based on the power plant operation data; S3. Based on the graph database model, extract the topological connection constraints and power equipment impedance parameters required for fault calculation, form a structured calculation data source, calculate the fault current of the fault point and related equipment, and generate a fault bus current table for each voltage level. S4. Based on the expert rule base and fault current, perform multi-dimensional verification of structured setting data and generate verification conclusions. S5. Visual output: Outputs a static topology diagram with labeled fault current, a comparison table of currents for multiple fault types, an equivalent circuit diagram of the impedance network, and the result of setting verification.

2. The method for network fault calculation and setting verification based on graph database according to claim 1, characterized in that: The parsing in step S1 specifically includes, Power equipment information parsing, based on a pre-built equipment parameter template library, uses natural language processing and keyword matching algorithms to locate and extract key information of power equipment from the parsed text, including nameplate parameters, impedance parameters and CT / PT ratio information; Setting information parsing: Through table recognition technology and setting item semantic understanding model, information is identified and extracted from relay protection setting sheets and calculation sheets to form a structured setting list; Power topology analysis involves parsing a primary wiring diagram and using image recognition and topology analysis algorithms to locate the coordinates of equipment and connecting segments in the primary wiring diagram, identify the connection relationships of electrical equipment within the site, and form a resolvable network topology data source.

3. The method for network fault calculation and setting verification based on graph database according to claim 1, characterized in that: Step S2, which involves constructing the graph database model, specifically includes: S21. Based on the Neo4j tag attribute graph model, design a graph database model framework for the connection relationships of plant equipment. include, Each node has a unique ID and attributes, representing the power equipment in the plant. Relationships, the relationships between nodes, are directional and represent the physical connections or logical associations between nodes; S22. Construct a static topology, including: Nodes are constructed, converting each power device into a node representation in a graph database model, with each node having a unique ID and attributes; Establish relationships by establishing connections between corresponding nodes based on the physical connections between power equipment and the protection configuration. Virtual nodes are used to represent T-connections and branch points.

4. The method for network fault calculation and setting verification based on graph database according to claim 1, characterized in that: Step S3 involves extracting the topology connectivity constraints and power equipment impedance parameters required for fault calculation. S31. Locate the target faulty bus from the graph database model, traverse all its associated primary devices through depth-first search, and output a local topology subgraph with the target faulty bus as the core. S32. Extract the power equipment impedance parameters from the node attributes of the graph database model, calculate the sequence impedance using the per-unit method, and generate a per-unit parameter table of the sequence impedance for each power equipment. S33. Based on the fault type, the power equipment sequence impedance of the local topology subgraph is spliced ​​with the equivalent sequence impedance of the external system in a static connection relationship to generate the corresponding sequence network impedance network.

5. The method for network fault calculation and setting verification based on graph database according to claim 4, characterized in that: The calculation of the fault current of the fault point and related equipment in step S3 specifically includes, S34. Calculation of symmetrical fault current at the fault point, the expression is as follows. In the formula, E represents the three-phase short-circuit current. eq Z represents the equivalent electromotive force. total1 Indicates the positive-sequence total impedance; S35. Calculation of asymmetrical fault current at the fault point, the expression is as follows. Sequence current, Phase current, I A = 3I1,I B =I C =0 In the formula, I1 represents the positive sequence current, I2 represents the negative sequence current, I0 represents the zero sequence current, and I... A I represents the phase A current. B I represents the phase B current. C E represents the C-phase current. eq Z represents the equivalent electromotive force. total1 Z represents the positive-sequence total impedance. total2 Z represents the negative sequence total impedance. total0 Represents the zero-sequence total impedance; S36. For upstream and downstream devices associated with a fault point, the current conduction path is determined using the connection matrix of the static topology. The fault current of the associated device is calculated using impedance voltage division and turns ratio calculation, as shown in the following expression. In the formula, I nodei This represents the fault current of the associated node. Z represents the three-phase short-circuit current. total1 Z represents the positive-sequence total impedance. i Z represents the impedance from node i to the fault point. total-i This represents the remaining network impedance.

6. The method for network fault calculation and setting verification based on graph database according to claim 1, characterized in that: The multi-dimensional cooperation verification in step S4 specifically includes, S41. Based on the static topology connection relationship and protection configuration relationship of the graph database model, locate the set of associated protection devices that have cooperation requirements with the target protection device, and construct the protection cooperation link; S42. Extract the setting parameters of all protection devices in the protection coordination link from the setting value library and graph database model, perform structured integration and consistency verification, eliminate data format differences, and output a structured setting value dataset. S43. Substitute the verification principles to perform time limit matching verification, current setting matching verification and sensitivity verification, and output the verification results and calculation sheet.

7. The method for network fault calculation and setting verification based on graph database according to claim 6, characterized in that: Step S43 specifically includes the time-limit coordination check, current setting coordination check, and sensitivity check. The time limit check is expressed as follows. Δt actual =t set1 -t set2 where, Δt actual represents the operating time difference between the upper and lower level protections, t set1 represents the operating time limit of the target protection, t set2 represents the operating time limit of the protection associated with the target; if Δt actual ≥ 0.5 s, it is qualified; The current setting is checked and verified using the following expression. K actual represents the coordination coefficient of upstream and downstream protection, I set1 represents the fault current of the target protection, I set1 represents the fault current of the protection associated with the target; if K actual ≥ 1.2, it is qualified; The sensitivity check expression is as follows. K s_actual I represents the protection sensitivity coefficient. dmin I represents the minimum fault current of the target protection. set This represents the setpoint for target protection; if K s_actual A value of ≥1.5 is considered acceptable.

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