Power distribution network power supply capability assessment method considering effective expansion of main transformer interconnection relationship

Abstract

The invention relates to the technical field of power distribution networks, in particular to a power distribution network power supply capability evaluation method considering effective expansion of a main transformer interconnection relation. In the prior art, an interconnection relation expansion constraint condition is only analyzed, the model and the number of feeder lines are determined based on known knowledge, a topological structure of the power distribution network is not analyzed in detail, an accurate connection relation between elements in the power distribution network cannot be known, and targeted optimization cannot be performed on line layout and load distribution according to an analysis result; the topological structure of the power distribution network is analyzed in detail through the topological structure analysis module, the network topology table is formed through the tree search method, the accurate connection relation between elements in the power distribution network can be known, and the line layout and load distribution can be conveniently and subsequently optimized in a targeted mode according to the analysis result.

Description

Technical Field

[0001] The present invention relates to the technical field of power distribution networks, and more specifically, to a method for evaluating the power supply capacity of a power distribution network taking into account the effective expansion of the interconnection relationship of main transformers. Background Art

[0002] In the process of upgrading and renovating the distribution network, a key task is to accurately calculate and evaluate the maximum power supply capacity of the distribution network, so as to provide operational power supply capacity guidance for the planning, design and operation of the distribution network; the maximum power supply capacity of the distribution network refers to the maximum load supply capacity of the distribution network under various operating constraints of the system within a certain power supply area; the maximum power supply capacity of the distribution network is an important indicator for evaluating the ultimate power supply capacity of the distribution system. It can be used to analyze the power supply capacity of the existing distribution network, discover the problems existing in the existing power supply structure and the corresponding weak links in the grid, and provide ideas for improving the existing power supply grid and expanding the grid structure to adapt to future load growth. It can also evaluate the power supply capacity of the distribution network under different operating modes through the maximum power supply capacity, and provide guidance for formulating safe, reliable and efficient distribution network operation methods.

[0003] The patent application with reference publication number CN105205740A discloses a method for evaluating the power supply capacity of a distribution network that takes into account the effective expansion of the main transformer interconnection relationship: determining the load carried by each main transformer under a given power supply capacity; the constraints that need to be considered for the expansion of the interconnection relationship; proposing a solution method based on the effective expansion of the main transformer interconnection relationship; proposing a medium-voltage distribution network power supply capacity evaluation process that takes into account the effective expansion of the main transformer interconnection relationship, including main transformer connection structure analysis; determining the load carried by the feeder; and power supply capacity calculation. The present invention can provide support for a comprehensive and effective evaluation of the power supply capacity of the existing distribution network structure, and improves the evaluation method for the power supply capacity of the medium-voltage distribution network, which is conducive to improving the management level of urban distribution network planning, promoting the rational development of urban power grid construction structure and planning technology, and has certain guiding significance for distribution network planning and power supply capacity evaluation;

[0004] However, when evaluating and analyzing the power supply capacity of the distribution network, the existing technology only analyzes the interconnection relationship expansion constraints and determines the feeder model and quantity based on known knowledge, but does not perform a detailed analysis of the distribution network topology. It is impossible to understand the precise connection relationship between the components in the distribution network, and it is impossible to ensure the accuracy of the evaluation results calculated by the distribution network power supply capacity evaluation model. It is impossible to optimize the line layout and load distribution according to the analysis results, thereby reducing the operating efficiency and safety of the distribution network. At the same time, it is impossible to judge and analyze whether the main transformer has a heavy overload risk based on the result data obtained from the distribution network power supply capacity evaluation model, and in the process of heavy overload risk judgment and analysis of the main transformer, it is impossible to combine the maximum allowable current of the main transformer for analysis, and it is impossible to warn the main transformer that has been severely overloaded.

[0005] To this end, we propose a distribution network power supply capacity evaluation method that takes into account the effective expansion of the main transformer interconnection relationship to address the above issues. Summary of the invention

[0006] The purpose of the present invention is to provide a distribution network power supply capacity evaluation method taking into account the effective expansion of the main transformer interconnection relationship, which solves the problem that the prior art does not perform a detailed analysis of the distribution network topology structure, cannot understand the precise connection relationship between the components in the distribution network, cannot ensure the accuracy of the evaluation results calculated by the distribution network power supply capacity evaluation model, cannot perform targeted optimization of the line layout and load distribution according to the analysis results, reduces the operation efficiency and operation safety of the distribution network, and at the same time cannot judge and analyze whether the main transformer has a heavy overload risk based on the result data obtained by the distribution network power supply capacity evaluation model, and cannot combine the maximum allowable current of the main transformer for analysis in the process of heavy overload risk judgment and analysis of the main transformer, and cannot warn the main transformer that has a heavy overload.

[0007] The purpose of the present invention can be achieved through the following technical solutions:

[0008] A method for evaluating the power supply capacity of a distribution network considering the effective expansion of the interconnection relationship between main transformers comprises the following steps:

[0009] Step 1: Collect historical power supply characteristic data of the distribution network;

[0010] Step 2: Preprocess the historical power supply characteristic data;

[0011] Step 3: Analyze the topological structure of the distribution network based on the preprocessed historical data;

[0012] Step 4: Based on the determined distribution network topology and combined with the N-1 safety criterion, a mathematical model for power supply capacity assessment is constructed;

[0013] Step 5: Use integer programming algorithm to solve the mathematical model of power supply capacity evaluation to obtain the maximum power supply capacity under the N-1 safety criterion;

[0014] Step 6: Collect the real-time operating load value of the main transformer of the distribution network, collect the real-time power supply characteristic data of the distribution network, and preprocess the real-time power supply characteristic data. Substitute the preprocessed real-time data into the mathematical model of power supply capacity evaluation to obtain the historical operating load value of the main transformer. Based on the real-time operating load value of the main transformer and the historical operating load value of the main transformer, judge and analyze whether the main transformer has a heavy overload risk.

[0015] As a preferred embodiment of the present invention, the power supply characteristic data includes the location of the main substation, the connection relationship of the main substation, feeder parameters, load distribution, switch status and transformer parameters. The real-time operating load value of the main transformer is the sum of the real-time operating loads of each main transformer in the distribution network. The real-time operating load of the main transformer is the load carried by the main transformer, and the load carried by the main transformer is equal to the product of the rated capacity of the main transformer and the load rate.

[0016] As a preferred implementation mode of the present invention, the specific process of the data preprocessing module performing data preprocessing operation on the historical power supply characteristic data and the real-time power supply characteristic data is as follows:

[0017] Data reception and verification: receiving historical power supply characteristic data and real-time power supply characteristic data collected by the data acquisition module, and performing preliminary verification of the data;

[0018] Data integration and conversion: merge, clean and integrate the data after preliminary verification;

[0019] Data cleaning and conversion: The integrated data is reviewed, outlier detection and processing is performed, missing value processing is performed, data duplication is removed, and data format is standardized;

[0020] Data desensitization: De-identify, generalize and encrypt the cleaned data in turn;

[0021] Result output: Send the preprocessed data to the management and control platform.

[0022] As a preferred implementation of the present invention, the specific process of analyzing the topological structure of the distribution network is as follows:

[0023] Obtain the wiring mode of the distribution network and determine the basic topology of the distribution network;

[0024] Numbering branches and nodes in the distribution network;

[0025] Use tree search method to form network topology table;

[0026] The power flow and voltage distribution of the power grid are analyzed by forward and backward substitution method;

[0027] Perform topology error identification regularly.

[0028] As a preferred embodiment of the present invention, the specific process of forming a network topology table using the tree search method is as follows:

[0029] Starting from the root node of the distribution network, take it as the root node of the topology tree;

[0030] Use a depth-first search algorithm to traverse the network;

[0031] During the depth-first search, each branch and node is explored, and their status and connection relationships are recorded;

[0032] As the depth-first search proceeds, the network topology table is gradually constructed;

[0033] When building the topology table, special attention is paid to handling loops or multipath situations;

[0034] After completing the preliminary topology table, verify and adjust it.

[0035] As a preferred embodiment of the present invention, the specific process of analyzing the power flow and voltage distribution of the power grid by the forward-backward substitution method is as follows:

[0036] Set the initial voltage values ​​of all nodes;

[0037] Starting from the end node of the distribution network, the calculation is carried forward layer by layer until the root node is reached. During the forward process, the power output of each node is calculated, which includes the load power of the node and the sum of the powers of all child nodes of the node. The calculation formula is:

[0038] P XL =P JF +∑P ZJ ;

[0039] Among them, P XL is the line power, P JF is the node load power, P ZJ is the child node power;

[0040] For each line, the power loss is calculated based on the line impedance and the current, which is obtained by dividing the node power by the node voltage;

[0041] Starting from the root node, the calculation is performed layer by layer until all the terminal nodes are reached. In the back-substitution process, the line power calculated in the forward direction and the known line impedance are used to calculate the line current. Then, the node voltage is updated according to the line current and the starting voltage. The calculation formula is:

[0042] V ZJ =V FJ -I XL ×Z XL ;

[0043] Among them, V ZJ is the child node voltage, V FJ is the parent node voltage, I XL is the line current, Z XL is the line impedance;

[0044] Repeat forward and backward calculations until the voltage changes of all nodes are lower than the preset convergence threshold, and obtain the final power flow and voltage distribution results;

[0045] Verify the calculation results.

[0046] As a preferred embodiment of the present invention, the mathematical formula used to construct the mathematical model for power supply capacity evaluation is as follows:

[0047] Maximum power supply capacity: Under the N-1 safety criterion, the maximum power supply capacity of the distribution network is calculated by the following formula:

[0048]

[0049] Among them, R m is the rated capacity of the main transformer m, T m is the load factor of the main transformer m;

[0050] Load transfer constraint: when the main transformer m fails, the load transfer size B to the main transformer n m,n The following constraints need to be met:

[0051] B m,n +R n ·T n ≤K·R n ;

[0052] Among them, R n is the rated capacity of the main transformer n, T n is the load factor of the main transformer n, K is the short-time allowable overload factor of the main transformer;

[0053] Communication capacity constraint: Transfer load B m,n Also affected by the interconnection line capacity C m,n Limitations:

[0054] B m,n ≤C m,n ;

[0055] Regional load constraints: In heavily loaded areas, the power supply capacity of the distribution network will be limited and must meet the following constraints:

[0056]

[0057] Where D is the total load demand of the area, and Z is the set of all main transformers in the area.

[0058] As a preferred embodiment of the present invention, under the condition of satisfying the N-1 safety criterion, the specific process of using the integer programming algorithm to solve the mathematical model of power supply capacity evaluation to obtain the maximum power supply capacity is as follows:

[0059] Define decision variables: Set the decision variable x m Represents the power supply capacity of each main transformer or feeder. These variables need to meet the operation constraints of the power grid and are integers because the switch state is either 0 or 1;

[0060] Constructing the objective function: The objective function aims to maximize the total power supply capacity of the distribution network, which is expressed as:

[0061]

[0062] Where Z is the total power supply capacity, x m is the power supply capacity of node m;

[0063] Write N-1 safety criterion constraints: For each main transformer or feeder, it is necessary to ensure that the system's power supply capacity can still meet the demand when any component fails. This is achieved through the following constraints:

[0064] Among them, D m is the load demand of node m. In addition, it is also necessary to ensure that under fault conditions, the power supply capacity of any main transformer does not exceed its rated capacity:

[0065] Where Rm is the rated capacity of the main transformer m;

[0066] Consider power flow constraints: Power flow constraints ensure that power flows in the grid are within technical limits, including voltage and line capacity limits:

[0067] P XS ≤P max ; Among them, P XS is the power loss of the line, P max is the maximum power capacity of the line;

[0068] Solve the integer programming problem: Use the integer programming algorithm to solve the mathematical model of power supply capacity evaluation. The integer programming problem is expressed as:

[0069]

[0070] subject to

[0071] Ax≤b

[0072] Where A is the technical constraint matrix, b is the constant vector on the right side;

[0073] Validation and Adjustment: Use test data to validate the solution results, ensure that they meet all constraints, and make necessary adjustments to the model.

[0074] As a preferred implementation of the present invention, the specific process of judging and analyzing whether the main transformer has a heavy overload risk is as follows:

[0075] Obtain the real-time operating load value and historical operating load value of the main transformer of the distribution network, and compare and analyze the real-time operating load value and historical operating load value of the main transformer:

[0076] If the real-time operating load value of the main transformer is greater than or equal to the historical operating load value of the main transformer, it is determined that the main transformer is in a state of heavy overload risk;

[0077] If the real-time operating load value of the main transformer is less than the historical operating load value of the main transformer, it is judged that the main transformer is in a normal working state;

[0078] When the main transformer is in a state of heavy overload risk, the real-time load current of the main transformer is immediately obtained, and the real-time load current of the main transformer is compared and analyzed with the preset heavy load warning value and the preset overload warning value:

[0079] If the real-time load current of the main transformer is greater than the preset overload warning value, which is 80% of the preset maximum allowable current of the main transformer, a main transformer overload warning signal is generated, and the main transformer overload warning signal is sent to the warning display module via the management platform;

[0080] If the real-time load current of the main transformer is greater than the preset overload warning value, the preset overload warning value is 100% of the preset main transformer maximum allowable current, a main transformer overload warning signal is generated, and the main transformer overload warning signal is sent to the warning display module via the management platform.

[0081] As a preferred embodiment of the present invention, it is applied to a distribution network power supply capacity evaluation system that takes into account the effective expansion of the main transformer interconnection relationship, including a management platform, a data acquisition module, a data preprocessing module, a topology structure analysis module, a power supply capacity evaluation module, a main transformer heavy overload risk analysis module and an early warning display module;

[0082] The data collection module collects historical power supply characteristic data and real-time power supply characteristic data;

[0083] The data preprocessing module performs data preprocessing operations on the historical power supply characteristic data and the real-time power supply characteristic data;

[0084] The topology analysis module analyzes the topology of the distribution network;

[0085] The power supply capacity evaluation module calculates the maximum power supply capacity of the distribution network by constructing a mathematical model for power supply capacity evaluation;

[0086] The main transformer heavy overload risk analysis module is used to judge and analyze whether the main transformer has a heavy overload risk;

[0087] The early warning display module receives the main transformer heavy load warning signal and the main transformer overload warning signal, and issues corresponding early warning information respectively.

[0088] Compared with the prior art, the advantages of the present invention are:

[0089] (1) In the present invention, the topological structure of the distribution network is analyzed in detail by the topological structure analysis module, and the network topology table is formed by the tree search method, so that the precise connection relationship between the components in the distribution network can be understood, which is convenient for the subsequent targeted optimization of the line layout and load distribution according to the analysis results. The power flow and voltage distribution of the power grid are obtained by the forward and backward method, which provides data for the subsequent distribution network power supply capacity evaluation model, and can ensure the accuracy of the evaluation results calculated by the distribution network power supply capacity evaluation model, thereby improving the operation efficiency and operation safety of the distribution network;

[0090] (2) In the present invention, the main transformer heavy overload risk analysis module compares and analyzes the main transformer historical operating load value obtained according to the distribution network power supply capacity evaluation model with the main transformer real-time operating load value to determine whether the main transformer has a heavy overload risk. If the main transformer is in a state of heavy overload risk, an in-depth analysis is performed in combination with the maximum allowable current of the main transformer, and a timely warning reminder is given to the main transformer that has been heavily overloaded, so that maintenance personnel can take corresponding treatment measures to ensure the safe and stable operation of the main transformer. BRIEF DESCRIPTION OF THE DRAWINGS

[0091] Figure 1 This is a block diagram of the method for evaluating the power supply capacity of a distribution network of the present invention;

[0092] Figure 2 is a system block diagram of the present invention;

[0093] Figure 3 It is a logical flow diagram of the present invention; Figure 4 A schematic diagram of the structure of an electronic device provided in Embodiment 3 of the present invention; Figure 5 A schematic diagram of the structure of a computer-readable storage medium provided in Embodiment 4 of the present invention. DETAILED DESCRIPTION

[0094] The following will combine the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all the embodiments. All other embodiments obtained by ordinary technicians in this field without creative work based on the embodiments of the present invention belong to the scope of protection of the present invention.

[0095] Embodiment 1: Figure 1As shown, the present invention proposes a method for evaluating the power supply capacity of a distribution network considering the effective expansion of the main transformer interconnection relationship, comprising the following steps:

[0096] Step 1: Collect historical power supply characteristic data of the distribution network, which includes the location of the main substation, the connection relationship of the main substation, feeder parameters, load distribution, switch status and transformer parameters;

[0097] Step 2: Preprocess the historical power supply characteristic data;

[0098] The specific process of the data preprocessing module performing data preprocessing operations on historical power supply characteristic data and real-time power supply characteristic data is as follows:

[0099] Data reception and verification: receiving historical power supply characteristic data and real-time power supply characteristic data collected by the data acquisition module, and performing preliminary verification of the data;

[0100] Data integration and conversion: merge, clean and integrate the data after preliminary verification;

[0101] The steps of data integration transformation usually include:

[0102] Data extraction: extract the required data from various data sources;

[0103] Data cleaning: remove duplication, denoise, and process missing values ​​on the extracted data to improve data quality;

[0104] Data conversion: Perform data type conversion, format conversion, and value range conversion operations as needed to meet the needs of subsequent analysis;

[0105] Data loading: Loading the cleaned and transformed data into the target database or data warehouse;

[0106] Data cleaning and conversion: The integrated data is reviewed, outlier detection and processing is performed, missing value processing is performed, data duplication is removed, and data format is standardized;

[0107] Data cleaning and transformation usually includes the following steps:

[0108] Data review: Conduct a comprehensive review of the original data to understand the structure, content and quality issues of the data;

[0109] Outlier detection and processing: Detect outliers through statistical methods or rules, and correct or delete them;

[0110] Missing value processing: use interpolation methods to fill in missing values, or make reasonable estimates based on business rules;

[0111] Data deduplication: Identify and delete duplicate records to ensure data uniqueness;

[0112] Data format standardization: convert data into a unified format, including date format and number format;

[0113] Data desensitization: De-identify, generalize and encrypt the cleaned data in turn;

[0114] De-identification is to reduce the association between data and personal identity by removing or replacing identifiers; generalization is to replace data values ​​with broader categories or ranges; encryption is to encrypt sensitive data using encryption algorithms, so that only users with the correct keys can decrypt and access the data;

[0115] Result output: Send the preprocessed data to the management and control platform;

[0116] The data preprocessing module performs preprocessing operations on the data collected by the acquisition module to improve data quality and enhance data availability, facilitate complex data analysis in subsequent processes, and improve the accuracy and reliability of analysis results;

[0117] Step 3: Analyze the topological structure of the distribution network based on the preprocessed historical data;

[0118] The specific process of analyzing the topological structure of the distribution network is as follows:

[0119] Obtain the wiring mode of the distribution network and determine the basic topology of the distribution network;

[0120] Number the branches and nodes in the distribution network. Usually, nodes are numbered starting from 0 and branches are numbered starting from 1. The root node is numbered 0, and other nodes are numbered in a hierarchical structure, ensuring that the parent node number is smaller than the child node;

[0121] Use tree search method to form network topology table;

[0122] The power flow and voltage distribution of the power grid are analyzed by forward and backward substitution method;

[0123] Perform topology error identification regularly.

[0124] As a preferred embodiment of the present invention, the specific process of forming a network topology table using the tree search method is as follows:

[0125] Starting from the root node of the distribution network, take it as the root node of the topology tree;

[0126] Use the depth-first search algorithm to traverse the network. During the search process, each node represents a switch or transformer, and the edge represents the line connecting these devices. The search is carried out according to the principle of "exploring as deep as possible" until the end node is reached;

[0127] During the depth-first search process, explore each branch and node, record their status and connection relationships, including recording the child nodes and parent nodes of each node, and the connection between them;

[0128] As the depth-first search proceeds, the network topology table is gradually constructed, which lists in detail each node and branch in the network, as well as the connection relationship between them;

[0129] When building the topology table, special attention is paid to handling loops or multipath situations;

[0130] After completing the preliminary topology table, verify and adjust it;

[0131] The specific process of analyzing the power flow and voltage distribution of the power grid by forward-backward substitution method is as follows:

[0132] Set the initial voltage value of all nodes, usually set to 1.0 unit voltage, this is to simplify the calculation, the actual voltage value will be gradually updated during the calculation process;

[0133] Starting from the end node of the distribution network, the calculation is carried forward layer by layer until the root node is reached. During the forward process, the power output of each node is calculated, which includes the load power of the node and the sum of the powers of all child nodes of the node. The calculation formula is:

[0134] P XL =P JF +∑P ZJ ;

[0135] Among them, P XL is the line power, P JF is the node load power, P ZJ is the child node power;

[0136] For each line, the power loss is calculated based on the line impedance and the current, which is obtained by dividing the node power by the node voltage;

[0137] Starting from the root node, the calculation is performed layer by layer until all the terminal nodes are reached. In the back-substitution process, the line power calculated in the forward direction and the known line impedance are used to calculate the line current. Then, the node voltage is updated according to the line current and the starting voltage. The calculation formula is:

[0138] V ZJ =V FJ -I XL ×Z XL ;

[0139] Among them, V ZJ is the child node voltage, V FJ is the parent node voltage, I XL is the line current, ZXL is the line impedance;

[0140] Repeat forward and backward calculations until the voltage changes of all nodes are lower than the preset convergence threshold, and obtain the final power flow and voltage distribution results;

[0141] Verify the calculation results;

[0142] Step 4: Based on the determined distribution network topology and combined with the N-1 safety criterion, a mathematical model for power supply capacity assessment is constructed;

[0143] The mathematical formula used to construct the mathematical model for power supply capacity assessment is as follows:

[0144] Maximum power supply capacity: Under the N-1 safety criterion, the maximum power supply capacity of the distribution network is calculated by the following formula:

[0145]

[0146] Among them, R m is the rated capacity of the main transformer m, T m is the load factor of the main transformer m;

[0147] Load transfer constraint: when the main transformer m fails, the load transfer size B to the main transformer n m,n The following constraints need to be met:

[0148] B m,n +R n ·T n ≤K·R n ;

[0149] Among them, R n is the rated capacity of the main transformer n, T n is the load factor of the main transformer n, K is the short-time allowable overload factor of the main transformer;

[0150] Communication capacity constraint: Transfer load B m,n Also affected by the interconnection line capacity C m,n Limitations:

[0151] B m,n ≤C m,n ;

[0152] Regional load constraints: In heavily loaded areas, the power supply capacity of the distribution network will be limited and must meet the following constraints:

[0153]

[0154] Where D is the total load demand of the region, and Z is the set of all main transformers in the region;

[0155] Step 5: Use integer programming algorithm to solve the mathematical model of power supply capacity evaluation to obtain the maximum power supply capacity under the N-1 safety criterion;

[0156] Under the condition of meeting the N-1 safety criterion, the specific process of using integer programming algorithm to solve the mathematical model of power supply capacity evaluation to obtain the maximum power supply capacity is as follows:

[0157] Define decision variables: Set the decision variable x m Represents the power supply capacity of each main transformer or feeder. These variables need to meet the operation constraints of the power grid and are integers because the switch state is either 0 or 1;

[0158] Constructing the objective function: The objective function aims to maximize the total power supply capacity of the distribution network, which is expressed as:

[0159]

[0160] Where Z is the total power supply capacity, x m is the power supply capacity of node m;

[0161] Write N-1 safety criterion constraints: For each main transformer or feeder, it is necessary to ensure that the system's power supply capacity can still meet the demand when any component fails. This is achieved through the following constraints:

[0162] Among them, D m is the load demand of node m. In addition, it is also necessary to ensure that under fault conditions, the power supply capacity of any main transformer does not exceed its rated capacity:

[0163] Where Rm is the rated capacity of the main transformer m;

[0164] Consider power flow constraints: Power flow constraints ensure that power flows in the grid are within technical limits, including voltage and line capacity limits:

[0165] P XS ≤P max ; Among them, P XS is the power loss of the line, P max is the maximum power capacity of the line;

[0166] Solve the integer programming problem: Use the integer programming algorithm to solve the mathematical model of power supply capacity evaluation. The integer programming problem is expressed as:

[0167]

[0168] subject to

[0169] Ax≤b

[0170] Where A is the technical constraint matrix, b is the constant vector on the right side;

[0171] Verify and adjust: Use test data to verify the solution results, ensure that they meet all constraints, and make necessary adjustments to the model;

[0172] Step 6: Collect the real-time operating load value of the main transformer of the distribution network. The real-time operating load value of the main transformer is the sum of the real-time operating loads of each main transformer in the distribution network. The real-time operating load of the main transformer is the load carried by the main transformer. The load carried by the main transformer is equal to the product of the rated capacity of the main transformer and the load rate. Collect the real-time power supply characteristic data of the distribution network, and pre-process the real-time power supply characteristic data. Substitute the pre-processed real-time data into the mathematical model of power supply capacity evaluation to obtain the historical operating load value of the main transformer. Based on the real-time operating load value of the main transformer and the historical operating load value of the main transformer, judge and analyze whether the main transformer has a heavy overload risk.

[0173] Embodiment 2: The technical solution of the embodiment of the present invention is different from that of embodiment 1 in that:

[0174] like Figure 2 As shown in the figure, the specific process of judging and analyzing whether the main transformer has a heavy overload risk is as follows:

[0175] Obtain the real-time operating load value and historical operating load value of the main transformer of the distribution network, and compare and analyze the real-time operating load value and historical operating load value of the main transformer:

[0176] If the real-time operating load value of the main transformer is greater than or equal to the historical operating load value of the main transformer, it is determined that the main transformer is in a state of heavy overload risk;

[0177] If the real-time operating load value of the main transformer is less than the historical operating load value of the main transformer, it is judged that the main transformer is in a normal working state;

[0178] When the main transformer is in a state of heavy overload risk, the real-time load current of the main transformer is immediately obtained, and the real-time load current of the main transformer is compared and analyzed with the preset heavy load warning value and the preset overload warning value:

[0179] If the real-time load current of the main transformer is greater than the preset overload warning value, which is 80% of the preset maximum allowable current of the main transformer, a main transformer overload warning signal is generated, and the main transformer overload warning signal is sent to the warning display module via the management platform;

[0180] If the real-time load current of the main transformer is greater than the preset overload warning value, which is 100% of the preset maximum allowable current of the main transformer, a main transformer overload warning signal is generated, and the main transformer overload warning signal is sent to the warning display module via the management platform;

[0181] It is applied to a distribution network power supply capacity evaluation system that takes into account the effective expansion of the main transformer interconnection relationship, including a management platform, a data acquisition module, a data preprocessing module, a topology structure analysis module, a power supply capacity evaluation module, a main transformer heavy overload risk analysis module and an early warning display module;

[0182] The management platform is connected to the data acquisition module and the early warning display module in one-way communication, the management platform is connected to the main transformer overload risk analysis module in two-way communication, the data acquisition module is connected to the data preprocessing module in one-way communication, the data preprocessing module is connected to the topology structure analysis module in one-way communication, the topology structure analysis module is connected to the power supply capacity analysis module in one-way communication, and the power supply capacity analysis module is connected to the main transformer overload risk analysis module in one-way communication;

[0183] A data collection module collects historical power supply characteristic data and real-time power supply characteristic data;

[0184] A data preprocessing module performs data preprocessing operations on historical power supply characteristic data and real-time power supply characteristic data;

[0185] Topology analysis module, which analyzes the topology of the distribution network;

[0186] The power supply capacity assessment module calculates the maximum power supply capacity of the distribution network by constructing a mathematical model for power supply capacity assessment;

[0187] The main transformer heavy overload risk analysis module is used to judge and analyze whether the main transformer has a heavy overload risk;

[0188] The early warning display module receives the main transformer heavy load warning signal and the main transformer overload warning signal, and issues corresponding early warning information respectively;

[0189] After receiving the main transformer overload warning signal, the early warning display module generates a text indicating that the main transformer is overloaded and needs maintenance, and sends it to the maintenance personnel. The maintenance personnel immediately take the following countermeasures: increase the transformer capacity, optimize power dispatching and load management, strengthen the monitoring of the main transformer operating status, and improve the heat dissipation conditions of the main transformer;

[0190] After receiving the main transformer overload warning signal, the early warning display module generates a main transformer overload maintenance required text and sends it to the maintenance personnel, who immediately take the following countermeasures:

[0191] Strengthen the construction of power distribution network, implement optimized grid dispatching, rationally plan grid load, distribute load reasonably, reduce the load of main transformers, and avoid overload;

[0192] By promoting knowledge on energy conservation and electricity safety, we can improve users' electricity skills and awareness of electricity safety, change consumption habits, and reduce load demand;

[0193] Regularly inspect and maintain power system equipment to ensure that the equipment is in good condition and reduce overload caused by equipment failure;

[0194] For main transformers that are often in an overload state, you can consider increasing their capacity to meet load requirements;

[0195] Install appropriate overcurrent protection devices on the input and output sides of the transformer to cut off the load circuit in time when the load exceeds the rated capacity to protect the safe operation of the transformer.

[0196] Example 3: Please refer to Figure 4 As shown, this embodiment discloses an electronic device, including a processor and a memory;

[0197] Wherein, the memory stores a computer program that can be called by the processor;

[0198] The processor executes the method for evaluating the power supply capacity of a distribution network taking into account the effective expansion of the interconnection relationship between main transformers by calling the computer program stored in the memory;

[0199] Since the electronic device introduced in this embodiment is an electronic device used to implement a distribution network power supply capacity assessment method that takes into account the effective expansion of the main transformer interconnection relationship in Example 1 of the present application, based on the distribution network power supply capacity assessment method that takes into account the effective expansion of the main transformer interconnection relationship introduced in the embodiment of the present application, technical personnel in this field can understand the specific implementation methods of the electronic device of this embodiment and its various variations, so how the electronic device implements the method in the embodiment of the present application will not be introduced in detail here; as long as technical personnel in this field implement the electronic device adopted by a distribution network power supply capacity assessment method that takes into account the effective expansion of the main transformer interconnection relationship in the embodiment of the present application, it belongs to the scope of protection of this application.

[0200] Example 4: Please refer to Figure 5 As shown, this embodiment discloses a computer-readable storage medium on which a rewritable computer program is stored;

[0201] When the computer program is executed, the method for evaluating the power supply capacity of a distribution network taking into account the effective expansion of the interconnection relationship between main transformers is implemented.

[0202] The working principle of the present invention is as follows: when in use, in the present invention, the topological structure of the distribution network is analyzed in detail by the topological structure analysis module, and the network topology table is formed by the tree search method, so that the precise connection relationship between the components in the distribution network can be understood, so as to facilitate the subsequent targeted optimization of the line layout and load distribution according to the analysis results, and the power flow and voltage distribution of the power grid are obtained by the forward push-back method, so as to provide data for the subsequent distribution network power supply capacity evaluation model, so as to ensure the accuracy of the evaluation results calculated by the distribution network power supply capacity evaluation model, improve the operation efficiency and operation safety of the distribution network, and compare and analyze the main transformer historical operation load value obtained according to the distribution network power supply capacity evaluation model with the main transformer real-time operation load value through the main transformer heavy overload risk analysis module to determine whether the main transformer has a heavy overload risk. If the main transformer is in a state of heavy overload risk, an in-depth analysis is performed in combination with the maximum allowable current of the main transformer, and a timely early warning reminder is given to the main transformer that has been heavily overloaded, so as to facilitate the maintenance personnel to take corresponding treatment measures to ensure the safe and stable operation of the main transformer.

[0203] The above are only preferred specific implementation modes of the present invention; however, the protection scope of the present invention is not limited thereto; any technician familiar with the technical field within the technical scope disclosed by the present invention; any equivalent replacement or change based on the technical solution and improved concept of the present invention shall be covered within the protection scope of the present invention.

Claims

1. A method for evaluating the power supply capacity of a distribution network considering the effective expansion of the interconnection relationship between main transformers, characterized in that: The following steps are involved: Step 1: Collect historical power supply characteristic data of the distribution network; Step 2: Preprocess the historical power supply characteristic data; Step 3: Analyze the topological structure of the distribution network based on the preprocessed historical data; Step 4: Based on the determined distribution network topology and combined with the N-1 safety criterion, a mathematical model for power supply capacity assessment is constructed; Step 5: Use integer programming algorithm to solve the mathematical model of power supply capacity evaluation to obtain the maximum power supply capacity under the N-1 safety criterion; Step 6: Collect the real-time operating load value of the main transformer of the distribution network, collect the real-time power supply characteristic data of the distribution network, and preprocess the real-time power supply characteristic data. Substitute the preprocessed real-time data into the mathematical model of power supply capacity evaluation to obtain the historical operating load value of the main transformer. Based on the real-time operating load value of the main transformer and the historical operating load value of the main transformer, judge and analyze whether the main transformer has a heavy overload risk.

2. A method for evaluating the power supply capacity of a distribution network considering the effective expansion of the main transformer interconnection relationship according to claim 1, characterized in that: The power supply characteristic data includes the location of the main substation, the connection relationship of the main substation, feeder parameters, load distribution, switch status and transformer parameters. The real-time operating load value of the main transformer is the sum of the real-time operating loads of each main transformer in the distribution network. The real-time operating load of the main transformer is the load carried by the main transformer, and the load carried by the main transformer is equal to the product of the rated capacity of the main transformer and the load rate.

3. A method for evaluating the power supply capacity of a distribution network considering the effective expansion of the main transformer interconnection relationship according to claim 1, characterized in that: The specific process of performing data preprocessing operations on historical power supply characteristic data and real-time power supply characteristic data is as follows: Data reception and verification: receiving historical power supply characteristic data and real-time power supply characteristic data collected by the data acquisition module, and performing preliminary verification of the data; Data integration and conversion: merge, clean and integrate the data after preliminary verification; Data cleaning and conversion: The integrated data is reviewed, outlier detection and processing is performed, missing value processing is performed, data duplication is removed, and data format is standardized; Data desensitization: De-identify, generalize and encrypt the cleaned data in turn; Result output: Send the preprocessed data to the management and control platform.

4. A method for evaluating the power supply capacity of a distribution network considering the effective expansion of the main transformer interconnection relationship according to claim 1, characterized in that: The specific process of analyzing the topological structure of the distribution network is as follows: Obtain the wiring mode of the distribution network and determine the basic topology of the distribution network; Numbering branches and nodes in the distribution network; Use tree search method to form network topology table; The power flow and voltage distribution of the power grid are analyzed by forward and backward substitution method; Perform topology error identification regularly.

5. A method for evaluating the power supply capacity of a distribution network considering the effective expansion of the main transformer interconnection relationship according to claim 4, characterized in that: The specific process of forming a network topology table using the tree search method is as follows: Starting from the root node of the distribution network, take it as the root node of the topology tree; Use a depth-first search algorithm to traverse the network; During the depth-first search, each branch and node is explored, and their status and connection relationships are recorded; As the depth-first search proceeds, the network topology table is gradually constructed; When building the topology table, special attention is paid to handling loops or multipath situations; After completing the preliminary topology table, verify and adjust it.

6. A method for evaluating the power supply capacity of a distribution network considering the effective expansion of the main transformer interconnection relationship according to claim 5, characterized in that: The specific process of analyzing the power flow and voltage distribution of the power grid by forward-backward substitution method is as follows: Set the initial voltage values ​​of all nodes; Starting from the end node of the distribution network, the calculation is carried forward layer by layer until the root node is reached. During the forward process, the power output of each node is calculated, which includes the load power of the node and the sum of the powers of all child nodes of the node. The calculation formula is: P XL =P JF +∑P ZJ ; Among them, P XL is the line power, P JF is the node load power, P ZJ is the child node power; For each line, the power loss is calculated based on the line impedance and the current, which is obtained by dividing the node power by the node voltage; Starting from the root node, the calculation is performed layer by layer until all the terminal nodes are reached. In the back-substitution process, the line power calculated in the forward direction and the known line impedance are used to calculate the line current. Then, the node voltage is updated according to the line current and the starting voltage. The calculation formula is: V ZJ =V FJ -I XL ×Z XL ; Among them, V ZJ is the child node voltage, V FJ is the parent node voltage, I XL is the line current, Z XL is the line impedance; Repeat forward and backward calculations until the voltage changes of all nodes are lower than the preset convergence threshold, and obtain the final power flow and voltage distribution results; Verify the calculation results.

7. A method for evaluating the power supply capacity of a distribution network considering the effective expansion of the main transformer interconnection relationship according to claim 1, characterized in that: The mathematical formula used to construct the mathematical model for power supply capacity assessment is as follows: Maximum power supply capacity: Under the N-1 safety criterion, the maximum power supply capacity of the distribution network is calculated by the following formula: Among them, R m is the rated capacity of the main transformer m, T m is the load factor of the main transformer m; Load transfer constraint: when the main transformer m fails, the load transfer size B to the main transformer n m,n The following constraints need to be met: B m,n +R n ·T n ≤K·R n ; Among them, R n is the rated capacity of the main transformer n, T n is the load factor of the main transformer n, K is the short-time allowable overload factor of the main transformer; Communication capacity constraint: Transfer load B m,n Also affected by the interconnection line capacity C m,n Limitations: B m,n ≤C m,n ; Regional load constraints: In heavily loaded areas, the power supply capacity of the distribution network will be limited and must meet the following constraints: Where D is the total load demand of the area, and Z is the set of all main transformers in the area.

8. A method for evaluating the power supply capacity of a distribution network considering the effective expansion of the main transformer interconnection relationship according to claim 7, characterized in that: Under the condition of meeting the N-1 safety criterion, the specific process of using integer programming algorithm to solve the mathematical model of power supply capacity evaluation to obtain the maximum power supply capacity is as follows: Define decision variables: Set the decision variable x m Represents the power supply capacity of each main transformer or feeder. These variables need to meet the operation constraints of the power grid and are integers because the switch state is either 0 or 1; Constructing the objective function: The objective function aims to maximize the total power supply capacity of the distribution network, which is expressed as: Where Z is the total power supply capacity, x m is the power supply capacity of node m; Write N-1 safety criterion constraints: For each main transformer or feeder, it is necessary to ensure that the system's power supply capacity can still meet the demand when any component fails. This is achieved through the following constraints: Among them, D m is the load demand of node m. In addition, it is also necessary to ensure that under fault conditions, the power supply capacity of any main transformer does not exceed its rated capacity: Where Rm is the rated capacity of the main transformer m; Consider power flow constraints: Power flow constraints ensure that power flows in the grid are within technical limits, including voltage and line capacity limits: P XS ≤P max ; Among them, P XS is the power loss of the line, P max is the maximum power capacity of the line; Solve the integer programming problem: Use the integer programming algorithm to solve the mathematical model of power supply capacity evaluation. The integer programming problem is expressed as: subject to Ax≤b Where A is the technical constraint matrix, b is the constant vector on the right side; Validation and Adjustment: Use test data to validate the solution results, ensure that they meet all constraints, and make necessary adjustments to the model.

9. A method for evaluating the power supply capacity of a distribution network considering the effective expansion of the interconnection relationship of main transformers according to claim 1, characterized in that: The specific process of judging and analyzing whether the main transformer has a heavy overload risk is as follows: Obtain the real-time operating load value and historical operating load value of the main transformer of the distribution network, and compare and analyze the real-time operating load value and historical operating load value of the main transformer: If the real-time operating load value of the main transformer is greater than or equal to the historical operating load value of the main transformer, it is determined that the main transformer is in a state of heavy overload risk; If the real-time operating load value of the main transformer is less than the historical operating load value of the main transformer, it is judged that the main transformer is in a normal working state; When the main transformer is in a state of heavy overload risk, the real-time load current of the main transformer is immediately obtained, and the real-time load current of the main transformer is compared and analyzed with the preset heavy load warning value and the preset overload warning value: If the real-time load current of the main transformer is greater than the preset overload warning value, which is 80% of the preset maximum allowable current of the main transformer, a main transformer overload warning signal is generated, and the main transformer overload warning signal is sent to the warning display module via the management platform; If the real-time load current of the main transformer is greater than the preset overload warning value, the preset overload warning value is 100% of the preset main transformer maximum allowable current, a main transformer overload warning signal is generated, and the main transformer overload warning signal is sent to the warning display module via the management platform.

10. A method for evaluating the power supply capacity of a distribution network considering the effective expansion of the interconnection relationship between main transformers according to any one of claims 1 to 9, characterized in that: It is applied to a distribution network power supply capacity evaluation system that takes into account the effective expansion of the main transformer interconnection relationship, including a management platform, a data acquisition module, a data preprocessing module, a topology structure analysis module, a power supply capacity evaluation module, a main transformer heavy overload risk analysis module and an early warning display module; The data collection module collects historical power supply characteristic data and real-time power supply characteristic data; The data preprocessing module performs data preprocessing operations on the historical power supply characteristic data and the real-time power supply characteristic data; The topology analysis module analyzes the topology of the distribution network; The power supply capacity evaluation module calculates the maximum power supply capacity of the distribution network by constructing a mathematical model for power supply capacity evaluation; The main transformer heavy overload risk analysis module is used to judge and analyze whether the main transformer has a heavy overload risk; The early warning display module receives the main transformer heavy load warning signal and the main transformer overload warning signal, and issues corresponding early warning information respectively.

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