Characteristic current-based transformer area topology identification method and system

Abstract

The invention relates to the technical field of transformer area topology identification, in particular to a transformer area topology identification method and system based on characteristic current. Comprising the following steps: S1, installing a current identification device at a distribution transformer, and collecting total characteristic current data through the current identification device; s2, the number of energy ports corresponding to the current identification device is obtained, the working state of each energy port is monitored, performance parameters of the energy ports are obtained at the same time, and a fluctuation range threshold value is set according to the performance parameters; current identification devices with Beidou positioning and elevation positioning functions are mounted at a distribution transformer and branches of a transformer area, different energy ports and branch lines can be accurately distinguished by utilizing characteristic current data and accurate position information of the devices, and the energy ports and branch lines can be accurately identified by comparing the characteristics of amplitude, phase and the like of the characteristic current data acquired by the devices. And the connection relationship between each branch line and the transformer can be clearly determined in combination with the geographic position relationship.

Description

Technical Field

[0001] The present invention relates to the technical field of substation topology identification, and in particular to a substation topology identification method and system based on characteristic current. Background Art

[0002] In the field of power systems, substation topology identification technology plays a vital role. Its purpose is to clearly understand the connection relationship between the distribution transformers and various branch lines and energy ports in the substation. Through accurate understanding of these connection structures, power companies can achieve efficient power distribution, timely fault detection and effective grid maintenance, thereby ensuring the stability and reliability of the power supply in the entire substation.

[0003] Currently, existing substation topology recognition technology is mainly used in conventional power supply scenarios. In traditional substation environments, which are relatively stable, with little equipment changes and little environmental interference, it can, to a certain extent, determine the connection relationships of some devices.

[0004] However, in the actual complex and changeable substation environment, relying solely on simple electrical quantity measurement methods cannot accurately distinguish different branch lines and energy ports with similar characteristics. For example, when the load characteristics of multiple branch lines are similar, their current magnitudes and voltage changes are similar. The existing technology is difficult to accurately identify the connection relationship between each branch, which seriously affects the accuracy of topology identification, resulting in the inability to achieve refined power distribution. Misjudgments are prone to occur during fault troubleshooting, delaying maintenance opportunities, and having limited effectiveness in practical applications. Therefore, a substation topology identification method and system based on characteristic current is proposed. Summary of the Invention

[0005] The purpose of the present invention is to provide a method and system for identifying substation topology based on characteristic current, so as to solve the problems raised in the above background technology.

[0006] To solve the above technical problems, one of the objectives of the present invention is to provide a method for identifying substation topology based on characteristic current, comprising the following steps:

[0007] S1. Install a current identification device at the distribution transformer and collect total characteristic current data through the current identification device;

[0008] S2. Obtain the number of energy ports corresponding to the current identification device, monitor the working status of each energy port, obtain performance parameters of the energy port, and set a fluctuation range threshold based on the performance parameters;

[0009] S3. When the energy port is detected to be in the working state of being turned on, the real-time total characteristic current data is compared and analyzed with the historical total characteristic current data of the adjacent time period, and the new characteristic current data is matched with the newly turned-on energy port according to the analysis result;

[0010] S4. Establish a sample database for each energy port, and record the characteristic current data in the sample database in combination with the matching energy port;

[0011] S5. When the working state of the energy port is monitored to fluctuate, the fluctuation difference data of the working state will be extracted and the energy port extraction will be reset based on the fluctuation range threshold;

[0012] S6. Calculate the matching value of the reset energy port in combination with the historical sample database for the unmatched characteristic current data, compare the matching values of different reset energy ports and characteristic current data, and select the reset energy port with the highest matching value to combine with the unmatched characteristic current data.

[0013] As a further improvement of this technical solution, in step S1, a current identification device is installed at the distribution transformer in the substation. At the same time, the current identification device has Beidou positioning and elevation positioning, so as to distinguish the current identification devices at each substation branch and communicate with the gateway of the distribution transformer to form the topology identification of the entire substation.

[0014] As a further improvement of the present technical solution, in step S1, the current identification device is powered by self-energy extraction, and the current identification device draws electricity from the cable to the inside of the device, thereby powering the current identification device, realizing real-time monitoring of changes in characteristic current data, and at the same time summarizing all collected characteristic current data into total characteristic current data.

[0015] As a further improvement of this technical solution, the steps of S2 are as follows:

[0016] S2.1. Differentially identify the energy end interface corresponding to each current identification device, and count the number of energy ports based on the identification results to obtain the number of energy ports corresponding to each current identification device;

[0017] S2.2. Obtain the performance parameters of each energy port and monitor the working status of each energy port at the same time. Then, set the fluctuation range threshold for the characteristic current data between different working states based on the historical working status and the performance parameters.

[0018] As a further improvement of this technical solution, the steps of S3 are as follows:

[0019] S3.1. When S2.2 detects that a new energy port is connected and in working state, extract the historical total characteristic current data extracted during the adjacent time periods of the new energy port in working state, then compare and analyze the real-time total characteristic current data with the extracted historical total characteristic current data, and use the difference characteristic current data between the real-time total characteristic current data and the historical total characteristic current data as the new characteristic current data based on the analysis results;

[0020] S3.2. Bind and match the new characteristic current data with the newly enabled energy port, so that the new characteristic current data represents the identification and authentication of the energy port.

[0021] As a further improvement of this technical solution, the steps of S3.1 are as follows:

[0022] S3.1.1. When the number of newly opened energy ports is greater than 1, skip step S3.2 and proceed directly to step S6;

[0023] S3.1.2. When the number of new energy ports opened is equal to 1, proceed to step S3.2.

[0024] As a further improvement of this technical solution, the steps of S5 are as follows:

[0025] S5.1. Extract the working status changes of each energy port and use the working status of the energy port when it is most recently reset as the basic status;

[0026] S5.2. The working status of the energy port after the change is combined with the basic status to extract the fluctuation difference data, and the fluctuation difference data is combined with the fluctuation range threshold to perform reset energy port extraction and comparison. When the fluctuation difference data is greater than the fluctuation range threshold, the energy port is marked as the reset energy port, thereby unbinding the bound characteristic current data. Conversely, when the fluctuation difference data is less than the fluctuation range threshold, monitoring is continued.

[0027] As a further improvement of this technical solution, the steps of S6 are as follows:

[0028] S6.1. Calculate matching values for all reset energy ports in combination with the historical sample database and unbound characteristic current data to obtain matching values for each reset energy port and each characteristic current data;

[0029] S6.2. Compare each characteristic current data with the matching value of each reset energy port, and select the energy port with the highest matching value and combine it with the unmatched characteristic current data;

[0030] When the number of unmatched characteristic current data and reset energy ports is 1 at the same time, binding matching is performed directly.

[0031] A second object of the present invention is to provide a substation topology identification system based on characteristic current, comprising any one of the above-mentioned substation topology identification methods based on characteristic current, including a current acquisition unit, a database recording unit, and a current identification and matching unit;

[0032] The current acquisition unit is used to collect total characteristic current data through the current identification device, obtain the number of energy ports corresponding to the current identification device, monitor the working status of each energy port, and obtain performance parameters of the energy port, and set the fluctuation range threshold according to the performance parameters;

[0033] The database recording unit is used to match the new characteristic current data with the newly opened energy port, establish a sample database for each energy port, and record the characteristic current data in combination with the matched energy port in the sample database;

[0034] The current identification and matching unit is used to extract the fluctuation difference data of the working state and extract the reset energy port in combination with the fluctuation range threshold, and at the same time compare the matching values of different reset energy ports with the characteristic current data, and select the reset energy port with the highest matching value to combine with the unmatched characteristic current data.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] 1. A method and system for identifying substation topology based on characteristic current. By installing current identification devices with Beidou positioning and elevation positioning at the substation distribution transformers and branches, and utilizing characteristic current data and the precise location information of the devices, different energy ports and branch lines can be accurately distinguished. By comparing the amplitude, phase and other characteristics of the characteristic current data collected by each device, combined with their geographical location relationship, the connection relationship between each branch line and the transformer can be clearly determined, and an accurate substation topology structure can be constructed. This precise topology identification helps power workers quickly understand the connection layout of power equipment in the substation, providing a reliable foundation for subsequent operation and maintenance, troubleshooting and other work.

[0037] 2. A method and system for identifying substation topology based on characteristic current. This method conducts in-depth comparison and analysis of the characteristic current data collected in real time with historical data. When a new energy port is connected or the working status changes, the historical total characteristic current data is extracted and matched with the real-time data. By calculating the matching value, the energy port with the highest matching value is selected and combined with the unmatched characteristic current data, thereby accurately identifying the position of the newly connected port in the topology structure. This method effectively improves the accuracy and reliability of topology identification and reduces misjudgments caused by data fluctuations or interference. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is the overall flow chart of the present invention;

[0039] Figure 2 A flowchart of obtaining the number of energy ports corresponding to each current identification device of the present invention;

[0040] Figure 3 A flowchart of the present invention for making the new characteristic current data represent the identification and authentication of the energy port;

[0041] Figure 4 This is a flowchart of the present invention using the working state of the energy port when the latest reset is completed as the basic state;

[0042] Figure 5 This is a flowchart of the present invention for selecting the energy port with the highest matching value and combining it with the unmatched characteristic current data. DETAILED DESCRIPTION

[0043] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0044] like Figure 1 - Figure 5 As shown, one of the purposes of the present invention is to provide a method for identifying substation topology based on characteristic current, comprising the following steps:

[0045] S1. Install a current identification device at the distribution transformer and collect total characteristic current data through the current identification device;

[0046] In step S1, a current identification device is installed at the distribution transformer in the substation. The current identification device is equipped with Beidou positioning and elevation positioning. This distinguishes the current identification devices at each substation branch and communicates with the gateway of the distribution transformer to form the topology identification of the entire substation. The specific steps are as follows:

[0047] Device installation and initialization: Accurately install a current identification device at the distribution transformer in the substation area to ensure that it can stably collect the total current data of the transformer. Configure the current identification device with a Beidou positioning module and an elevation positioning module, enable the positioning function, and perform initialization settings to enable it to accurately obtain its own geographic location information.

[0048] Positioning and distinguishing devices in substation branches: Current identification devices with the same positioning function are installed at each substation branch. After startup, these devices use the Beidou positioning system to obtain their own longitude and latitude coordinates and the elevation positioning module to obtain altitude information. At the same time, a device information database is established, and the unique identifier of each current identification device (such as the device number) is associated and stored with its obtained geographic location information (longitude and latitude, elevation). This unique geographic location information is used to clearly distinguish the current identification devices at each substation branch.

[0049] Current data collection and transmission: The current identification device at the distribution transformer continuously collects the total current data of the transformer at a set sampling frequency (e.g., 100 times per second) and performs preliminary processing on the collected data. The current identification device at the branch of the substation also collects the current data of the branch line at the same or appropriate sampling frequency and performs the same preprocessing. After that, each current identification device packages the processed current data and its own geographic location information (obtained through positioning) into a specific data frame format and transmits it to the distribution transformer gateway through the established communication link;

[0050] Topology identification and construction: The gateway receives data from each current identification device and begins to identify the substation topology based on the geographic location information and current data characteristics in the data. First, the location of the current identification device at the distribution transformer is used as the starting point. By analyzing the geographic location relationship (such as distance and azimuth) between the current identification device at the substation branch and the device at the transformer, as well as the correlation of current data (such as current magnitude change trend and phase relationship), the connection relationship of the branch line is determined, and a substation topology map is constructed. The distribution transformer is used as the central node, and the current identification devices at each substation branch are used as branch nodes. Line segments are used to represent the electrical connection relationship between them, forming the topology structure of the entire substation.

[0051] At the same time, data caching and batch transmission strategies are adopted between current identification devices. The current identification device first caches the collected current data, and then sends it in batches when the cached data reaches a certain level (such as set to 100 data points). Assuming that it was originally sent every time one data point was collected, it is now sent once every 100 data points. The sending time is changed from 0.1s to 0.5s (taking into account the additional time for data packaging, etc.), but the number of transmissions is changed from 100 times to 1 time. The receiving end also adjusts the receiving strategy accordingly to reduce unnecessary receiving time. This can significantly reduce the total time of the sending and receiving states and reduce power consumption;

[0052] At the same time, a reasonable sleep and wake-up mechanism is set up in the current identification device. According to the frequency of change of current data, if the current data changes slowly over a period of time, a longer sleep time can be set. When it is detected that the current data fluctuation is less than a certain threshold within 10 minutes, the communication module is put into sleep state for 5 minutes and wakes up only when needed for data interaction. This can greatly increase the proportion of sleep time and reduce total power consumption. Because the power consumption in the sleep state is extremely low, extending the sleep time can effectively reduce overall energy consumption. The formula is as follows:

[0053]

[0054] Wherein, η represents the power consumption reduction ratio, I tx is the sending current, that is, the current in the circuit when the current identification device performs data sending operation, I rx is the receiving current, that is, the current in the circuit when the current identification device is performing data receiving operation, V is the voltage, P sleep is the power consumption in sleep state, T sleep1 is the original sleep time before optimization measures are taken, T sleep2 is the adjusted sleep time after optimization measures are taken, 100 is based on the original situation of sending 100 single data points, 99 is obtained by 100-1, where 100 is the number of times a single data point was originally sent, 1 is the number of times 100 data points were sent after optimization, and 100% is used to convert the calculation result into a percentage;

[0055] ΔT=9.5+100t rx1 -t rx2

[0056] Where ΔT is the total time change, t rx1 is the original time of receiving a single data point, that is, before taking optimization measures, t rx2 is the time to receive 100 data points after adjustment. That is, after taking optimization measures, 9.5 is obtained by subtracting 10 from 0.5. 0.5 is the time to send 100 data points after optimization, and 9.5 represents the difference in sending time.

[0057]

[0058] Among them, Δβ is the change in the proportion of sleep time, and T is the total time.

[0059] In step S1, the current identification device is powered by self-powered energy. The current identification device draws power from the cable to the inside of the device, thereby powering the current identification device and realizing real-time monitoring of changes in characteristic current data. At the same time, all collected characteristic current data are summarized into total characteristic current data. The specific steps are as follows:

[0060] Device connection and induction: Reliably connect the energy acquisition module of the current identification device to the power supply cable of the distribution transformer in the substation area. The energy acquisition module generally uses the principle of electromagnetic induction and is tightly wrapped around the outside of the cable. When current flows through the cable, according to the law of electromagnetic induction, an induced electromotive force is generated in the energy acquisition module.

[0061] Energy conversion and storage: The induced electromotive force generated by the energy acquisition module passes through the rectifier circuit to convert AC power into DC power. The rectifier circuit can adopt common circuit structures such as diode bridge rectification to ensure the stability of the output current. The converted DC power is stabilized by the voltage stabilizing circuit to meet the operating voltage requirements of the electronic components inside the current identification device. The voltage stabilizing circuit can adopt a linear voltage stabilizing chip or a switching voltage stabilizing chip, which is selected according to the power consumption of the device and the requirements for power supply stability. Then, a part of the stabilized electric energy directly powers the real-time monitoring circuit of the current identification device, enabling it to continuously monitor changes in characteristic current data. The other part of the electric energy is stored in energy storage elements (such as supercapacitors or rechargeable batteries) to provide a continuous and stable power supply to the device in the event of short-term fluctuations in cable current or other abnormal conditions;

[0062] Power management and control: The current identification device is equipped with a power management module that monitors the power obtained by the energy acquisition module, the power of the energy storage element, and the power consumption of the device in real time. When the power obtained by the energy acquisition module is sufficient and the power consumption of the device is low, the power management module controls the charging of the energy storage element and ensures stable power supply to the monitoring circuit. When the cable current decreases, resulting in insufficient energy or a sudden increase in the power consumption of the device, the power management module automatically switches to prioritize the use of the power in the energy storage element to ensure uninterrupted operation of the device.

[0063] Local data collection and processing: The current identification device collects the characteristic current in the cable through the internal current sensor according to the set sampling frequency (such as 100 times per second). The current sensor can use a high-precision sensor such as a Hall current sensor to ensure the accuracy of the collected data. The collected raw current data is first amplified by the preamplifier circuit to convert the weak current signal into a voltage signal suitable for subsequent processing. The gain of the amplifier circuit needs to be reasonably set according to the output characteristics of the current sensor and the processing capacity of the device. The amplified signal passes through the filter circuit to remove the noise and interference components in the signal. The filter circuit can adopt various forms such as low-pass filtering and band-pass filtering, and is selected according to the frequency range and noise characteristics of the actual current signal. The data after filtering is the characteristic current data monitored by the device;

[0064] Data aggregation and transmission: The current identification device at each substation branch packages the locally processed characteristic current data to form a specific data frame format. In addition to the characteristic current data, the data frame should also contain the unique identification of the device (such as the device number), collection time and other information. The current identification devices at all substation branches transmit the packaged data frames to the main current identification device or gateway at the distribution transformer through the previously established communication link (such as 4G, LoRa and other wireless communications or Ethernet wired communications). The main current identification device or gateway at the distribution transformer receives the data frames from the devices in each substation branch and classifies and organizes the data according to the device identification. Then, the characteristic current data of each branch are aggregated to obtain the total characteristic current data of the entire substation. The aggregation method can be a simple numerical addition or a weighted summation based on the weights of different branches, depending on the electrical structure and monitoring requirements of the substation.

[0065] S2. Obtain the number of energy ports corresponding to the current identification device, monitor the working status of each energy port, obtain performance parameters of the energy port, and set a fluctuation range threshold based on the performance parameters;

[0066] The steps of S2 are as follows:

[0067] S2.1. Differentially identify the energy end interface corresponding to each current identification device, and count the number of energy ports based on the identification results to obtain the number of energy ports corresponding to each current identification device. The specific steps are as follows:

[0068] Energy-end interface characteristic data collection: The current identification device collects electrical parameters such as current, voltage, and power factor of each connected energy port in real time at a set sampling frequency. These parameters serve as basic data for identifying differences in energy-end interfaces. For each energy port, in addition to collecting electrical parameters, time information such as the port's connection and disconnection time is also recorded. This time information facilitates subsequent analysis of the energy port's usage and operating status.

[0069] Interface difference identification: Based on the collected electrical parameters, the characteristic values of each energy port are calculated, including the average current, maximum power, power factor variation range, etc. These characteristic values can reflect the operating characteristics and differences of the energy ports;

[0070] Pattern recognition or machine learning algorithms (such as cluster analysis and neural networks) are used to analyze and compare the characteristic values of different energy ports. Through these algorithms, energy ports with similar characteristic values are grouped together, and energy ports with significantly different characteristic values are distinguished. For energy ports with different load types (such as resistive load, inductive load, and capacitive load), their electrical parameter characteristic values will have obvious differences, and the algorithm can accurately identify these differences.

[0071] Energy port quantity statistics: After completing the energy end interface difference identification, count the different types of energy ports corresponding to each current identification device. According to the results of the difference identification, classify each energy port into the corresponding category, and count the number of ports in each category.

[0072] S2.2. Obtain the performance parameters of each energy port and monitor the working status of each energy port. Then, based on the historical working status and performance parameters, set the fluctuation range threshold for the characteristic current data between different working states. The specific steps are as follows:

[0073] Performance parameter acquisition: The current identification device collects the current of each energy port in real time according to the set sampling frequency;

[0074] Working status monitoring: The working status of the energy port is determined based on parameters such as current and power. When the current is greater than a preset start threshold (such as 10% of the rated current) and the power is greater than zero, the energy port is considered to be in the "on" working state; when the current is less than a shutdown threshold (such as 5% of the rated current) and the power is close to zero, the energy port is considered to be in the "off" working state.

[0075] Historical data collection and analysis: Store historical performance parameters and working status data of all energy ports, and classify and store the data in chronological order and energy port number for subsequent query and analysis;

[0076] Set the fluctuation range threshold: Based on the statistical analysis results of historical data, combined with the actual operation of the energy port and device characteristics, set the fluctuation range threshold for the characteristic current data between different working states. The formula is as follows:

[0077]

[0078] Where I is the average current, n is the number of data samples, and I i is the current value of the i-th sample;

[0079]

[0080] Among them, σ I is the standard deviation of the current;

[0081]

[0082] Among them, I lower is the lower threshold of the fluctuation range, I upper is the upper threshold of the fluctuation range, k is the coefficient, and its value ranges from 2 to 3.

[0083] S3. When the energy port is detected to be in the working state of being turned on, the real-time total characteristic current data is compared and analyzed with the historical total characteristic current data of the adjacent time period, and the new characteristic current data is matched with the newly turned-on energy port according to the analysis result;

[0084] The steps for S3 are as follows:

[0085] S3.1. When S2.2 detects that a new energy port is connected and in working state, extract the historical total characteristic current data extracted during the adjacent time periods of the new energy interface in working state, then compare and analyze the real-time total characteristic current data with the extracted historical total characteristic current data. Based on the analysis results, the difference characteristic current data between the real-time total characteristic current data and the historical total characteristic current data is used as the new characteristic current data. The specific steps are as follows:

[0086] Energy port access monitoring: The current identification device continuously monitors the electrical parameters of each energy port, such as current and voltage. When it detects that the current of an energy port suddenly rises from near zero and the increase exceeds a preset startup threshold (for example, 10% of the rated current), while the voltage remains within the normal operating range, the energy port is determined to be newly connected and is turned on. Once a new connection event is detected, the event timestamp is immediately recorded.

[0087] Historical data extraction: Based on the timestamp of the new energy port's working status, determine the time range of adjacent time periods. Generally speaking, the adjacent time period can be selected from the period before the new port is turned on, such as the interval from 5 minutes to 1 minute before. The specific duration can be adjusted according to the actual situation and system characteristics. Based on the determined time range, retrieve and extract the total characteristic current data within the period from the historical database;

[0088] Comparative analysis of new current data: The extracted historical total characteristic current data and real-time total characteristic current data are aligned in time series to ensure comparability between the two in the time dimension. A difference comparison method is used to calculate the difference between the real-time total characteristic current data and the historical total characteristic current data at each time point. Based on the comparison results, the degree of difference between the real-time total characteristic current data and the historical total characteristic current data is evaluated;

[0089] Determination of new characteristic current data: The difference between the real-time total characteristic current data and the historical total characteristic current data is used as the new characteristic current data. Specifically, for each time point, the real-time total characteristic current data is subtracted from the corresponding historical total characteristic current data to obtain the difference current value at that time point.

[0090] The steps of S3.1 are as follows:

[0091] S3.1.1. When the number of newly opened energy ports is greater than 1, skip step S3.2 and proceed directly to step S6;

[0092] S3.1.2. When the number of new energy ports opened is equal to 1, proceed to step S3.2.

[0093] S3.2. Bind and match the new characteristic current data with the newly enabled energy port, so that the new characteristic current data represents the identification and authentication of the energy port.

[0094] S4. Create a sample database for each energy port and record the characteristic current data in the sample database in combination with the matching energy port. The specific steps are as follows:

[0095] Sample database architecture design: Create an energy port information table to record basic information about each energy port, such as port number, device name, device type, rated power, and rated current. Create a characteristic current data table to store characteristic current data. This table should contain fields such as timestamp, current value, voltage value, and power factor. Also, set a foreign key field to associate the port number in the energy port information table.

[0096] Data collection and collation: Verify the basic information of each energy port to ensure its accuracy and completeness. If a new energy port is connected or the information of an existing port changes, update the energy port information table in a timely manner;

[0097] Data matching and association: Based on the results of the previous binding and matching of the new characteristic current data with the energy port, the characteristic current data is associated with the corresponding energy port number to ensure that each characteristic current data can be accurately mapped to the corresponding energy port;

[0098] Data entry sample database: Insert the pre-processed and associated characteristic current data into the characteristic current data table in chronological order. When inserting the data, fill in the corresponding timestamp, energy port number and other fields at the same time.

[0099] S5. When the working state of the energy port is monitored to fluctuate, the fluctuation difference data of the working state will be extracted and the energy port extraction will be reset based on the fluctuation range threshold;

[0100] The steps for S5 are as follows:

[0101] S5.1. Extract the working status changes of each energy port and use the working status of the energy port when it is most recently reset as the basic status;

[0102] S5.2. The working status of the energy port after the change is combined with the basic status to extract the fluctuation difference data, and the fluctuation difference data is combined with the fluctuation range threshold to perform the reset energy port extraction and comparison. When the fluctuation difference data is greater than the fluctuation range threshold, the energy port is marked as the reset energy port, thereby unbinding the bound characteristic current data. Conversely, when the fluctuation difference data is less than the fluctuation range threshold, the monitoring is continued. The specific formula is as follows:

[0103] Δx=x1-x0

[0104] Among them, Δx is the fluctuation difference of the parameter, x1 is the value of the parameter in the basic state, and x0 is the value of the parameter after the change.

[0105]

[0106] Among them, r is the fluctuation rate of the parameter;

[0107] When Δx>θ, the fluctuation difference data of the parameter is greater than the fluctuation range threshold;

[0108] When r<θ, the fluctuation difference data of the parameter is greater than the fluctuation range threshold;

[0109] Among them, θ is the fluctuation range threshold of the parameter;

[0110] For difference judgment, θ is a fixed difference threshold;

[0111] For rate of change judgment, θ is the percentage threshold.

[0112] S6. Calculate the matching value of the reset energy port in combination with the historical sample database for the unmatched characteristic current data, compare the matching values of different reset energy ports and characteristic current data, and select the reset energy port with the highest matching value to combine with the unmatched characteristic current data.

[0113] The steps for S6 are as follows:

[0114] S6.1. Calculate matching values for all reset energy ports in combination with the historical sample database and unbound characteristic current data to obtain matching values for each reset energy port and each characteristic current data;

[0115] S6.2. Compare each characteristic current data with the matching value of each reset energy port, and select the energy port with the highest matching value and combine it with the unmatched characteristic current data;

[0116] When the number of unmatched characteristic current data and reset energy ports is 1 at the same time, binding matching is performed directly. The specific steps are as follows:

[0117] Feature extraction and quantification: For each reset energy port, extract its features from the historical sample database, such as average current, current fluctuation range, current change trend, etc., and quantify these features. Perform feature extraction on unmatched characteristic current data, and similarly extract and quantify features such as current amplitude, phase, frequency, and harmonic content.

[0118] Matching value calculation: calculating the matching value between each reset energy port and each unmatched characteristic current data;

[0119] Matching value comparison and combination: For each unmatched characteristic current data, compare it with the matching values calculated by all reset energy ports, select the reset energy port with the highest matching value and combine it with the unmatched characteristic current data to establish a binding relationship. The formula is as follows:

[0120]

[0121] The eigenvector of the reset energy port is W=(w1, w2, ..., w j ), the eigenvector of the unmatched characteristic current data is V=(v1, v2, ..., v j ), m is the number of features, and d(W, V) represents the Euclidean distance;

[0122]

[0123] Among them, M E is the matching value, and α is a constant used to avoid the denominator being zero and ensure the stability and feasibility of the calculation.

[0124] A second object of the present invention is to provide a substation topology identification system based on characteristic current, including any one of the above-mentioned substation topology identification methods based on characteristic current, including a current acquisition unit, a database recording unit, and a current identification and matching unit;

[0125] The current acquisition unit is used to collect total characteristic current data through the current identification device, obtain the number of energy ports corresponding to the current identification device, monitor the working status of each energy port, and obtain the performance parameters of the energy port, and set the fluctuation range threshold according to the performance parameters;

[0126] The database recording unit is used to match the new characteristic current data with the newly opened energy port, establish a sample database for each energy port, and record the characteristic current data in combination with the matched energy port in the sample database;

[0127] The current identification and matching unit is used to extract the fluctuation difference data of the working state and extract the reset energy port in combination with the fluctuation range threshold. At the same time, the matching values of different reset energy ports and characteristic current data are compared, and the reset energy port with the highest matching value is selected and combined with the unmatched characteristic current data.

[0128] The above shows and describes the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely preferred examples of the present invention and are not intended to limit the present invention. Various changes and improvements may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and improvements fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for identifying substation topology based on characteristic current, characterized by: The steps include: S1. Install a current identification device at the distribution transformer and collect total characteristic current data through the current identification device; S2. Obtain the number of energy ports corresponding to the current identification device, monitor the working status of each energy port, obtain performance parameters of the energy port, and set a fluctuation range threshold based on the performance parameters; S3. When the energy port is detected to be in the working state of being turned on, the real-time total characteristic current data is compared and analyzed with the historical total characteristic current data of the adjacent time period, and the new characteristic current data is matched with the newly turned-on energy port according to the analysis result; S4. Establish a sample database for each energy port, and record the characteristic current data in the sample database in combination with the matching energy port; S5. When the working state of the energy port is monitored to fluctuate, the fluctuation difference data of the working state will be extracted and the energy port extraction will be reset based on the fluctuation range threshold; S6. Calculate the matching value of the reset energy port in combination with the historical sample database for the unmatched characteristic current data, compare the matching values of different reset energy ports and characteristic current data, and select the reset energy port with the highest matching value to combine with the unmatched characteristic current data.

2. The method for identifying substation topology based on characteristic current according to claim 1, characterized in that: In step S1, a current identification device is installed at the distribution transformer in the substation. At the same time, the current identification device is equipped with Beidou positioning and elevation positioning, so as to distinguish the current identification devices at each substation branch and communicate with the gateway of the distribution transformer to form the topology identification of the entire substation.

3. The method for identifying substation topology based on characteristic current according to claim 1, characterized in that: In step S1, the current identification device is powered by self-energy extraction. The current identification device draws electricity from the cable to the inside of the device, thereby powering the current identification device, realizing real-time monitoring of changes in characteristic current data, and at the same time summarizing all collected characteristic current data into total characteristic current data.

4. The method for identifying substation topology based on characteristic current according to claim 1, characterized in that: The steps of S2 are as follows: S2.

1. Differentially identify the energy end interface corresponding to each current identification device, and count the number of energy ports based on the identification results to obtain the number of energy ports corresponding to each current identification device; S2.

2. Obtain the performance parameters of each energy port and monitor the working status of each energy port at the same time. Then, set the fluctuation range threshold for the characteristic current data between different working states based on the historical working status and the performance parameters.

5. The method for identifying substation topology based on characteristic current according to claim 1, characterized in that: The steps of S3 are as follows: S3.

1. When S2.2 detects that a new energy port is connected and in working state, extract the historical total characteristic current data extracted during the adjacent time periods of the new energy port in working state, then compare and analyze the real-time total characteristic current data with the extracted historical total characteristic current data, and use the difference characteristic current data between the real-time total characteristic current data and the historical total characteristic current data as the new characteristic current data based on the analysis results; S3.

2. Bind and match the new characteristic current data with the newly enabled energy port, so that the new characteristic current data represents the identification and authentication of the energy port.

6. The method for identifying substation topology based on characteristic current according to claim 1, characterized in that: The steps of S3.1 are as follows: S3.1.

1. When the number of newly opened energy ports is greater than 1, skip step S3.2 and proceed directly to step S6; S3.1.

2. When the number of new energy ports opened is equal to 1, proceed to step S3.

2.

7. The method for identifying substation topology based on characteristic current according to claim 1, characterized in that: The steps of S5 are as follows: S5.

1. Extract the working status changes of each energy port and use the working status of the energy port when it is most recently reset as the basic status; S5.

2. The working status of the energy port after the change is combined with the basic status to extract the fluctuation difference data, and the fluctuation difference data is combined with the fluctuation range threshold to perform reset energy port extraction and comparison. When the fluctuation difference data is greater than the fluctuation range threshold, the energy port is marked as the reset energy port, thereby unbinding the bound characteristic current data. Conversely, when the fluctuation difference data is less than the fluctuation range threshold, monitoring is continued.

8. The method for identifying substation topology based on characteristic current according to claim 1, characterized in that: The steps of S6 are as follows: S6.

1. Calculate matching values for all reset energy ports in combination with the historical sample database and unbound characteristic current data to obtain matching values for each reset energy port and each characteristic current data; S6.

2. Compare each characteristic current data with the matching value of each reset energy port, and select the energy port with the highest matching value and combine it with the unmatched characteristic current data; When the number of unmatched characteristic current data and reset energy ports is 1 at the same time, binding matching is performed directly.

9. A system for identifying substation topology based on characteristic current, for implementing the method for identifying substation topology based on characteristic current according to any one of claims 1 to 8, characterized in that: It includes a current acquisition unit, a database recording unit and a current identification and matching unit; The current acquisition unit is used to collect total characteristic current data through the current identification device, obtain the number of energy ports corresponding to the current identification device, monitor the working status of each energy port, and obtain performance parameters of the energy port, and set the fluctuation range threshold according to the performance parameters; The database recording unit is used to match the new characteristic current data with the newly opened energy port, establish a sample database for each energy port, and record the characteristic current data in combination with the matched energy port in the sample database; The current identification and matching unit is used to extract the fluctuation difference data of the working state and extract the reset energy port in combination with the fluctuation range threshold, and at the same time compare the matching values of different reset energy ports with the characteristic current data, and select the reset energy port with the highest matching value to combine with the unmatched characteristic current data.

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