Low-voltage transformer area system dynamic monitoring method based on topology identification

Abstract

The invention relates to the technical field of power distribution network monitoring, in particular to a low-voltage transformer area system dynamic monitoring method based on topology recognition, which comprises the following steps: S1, timing; s2, acquiring active power data of 96 points; s3, monitoring the state of the power grid, judging whether topological calculation needs to be started or not, if yes, entering S4, and if not, continuing monitoring; s4, selecting a transformer area which needs to start slope separation calculation to carry out topological calculation; and S5, comparing the calculated topology result with the previous topology result, updating if there is a difference, and performing abnormal line loss analysis if there is no difference but the transformer area has a high loss condition. According to the power grid state, topology identification calculation is automatically started, the superior-subordinate relationship of the measurement equipment can be sorted out only by using the electric quantity or the power value of the measurement equipment in the topology identification calculation process, difference comparison is performed based on a topology calculation result, the line loss condition is judged, and dynamic monitoring is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of distribution network monitoring, and in particular to a low-voltage substation system dynamic monitoring method based on topology recognition. Background Art

[0002] The topological relationship refers to the relationship between each meter in the substation and the circuit breaker at each node in the substation. Unclear topological relationships will cause large errors in the substation and phase line loss analysis data, unreasonable arrangement of new loads for business expansion, affecting load balancing, and reducing the success rate of remote fee control and remote recharge. If the topological relationship is inaccurate, when an accident occurs in the substation and needs emergency repair, the rationality and safety of the emergency repair strategy and the timeliness of the emergency repair project will be affected due to incorrect load affiliation data. Due to changes in user information, replacement of meter failures, and upgrades to substations, the current system topological relationship often changes. Existing communication methods such as low-voltage power line carriers and micro-power wireless have the ability to communicate and read across substations, which brings great challenges to the development of topological relationship sorting.

[0003] Existing topology identification methods include a method of detecting the power supply status of the line after an artificial power outage to identify the substation. This method is easy to use and has high accuracy, but it is inefficient and power outages affect customer experience. There is also the use of signal injection, which detects the injected signal at the upper node to comb the topology, but this injected signal will affect the power quality and the injected equipment is prone to heat and damage. There is also the use of traditional big data methods to comb the topology, such as a method for intelligent low-voltage distribution substation topology identification based on feature information correlation disclosed in publication number CN116436152A, but it is necessary to set the equipment type numbers of intelligent circuit breakers at all levels in the substation, substation assessment tables, and substation user tables. Summary of the invention

[0004] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a low-voltage substation system dynamic monitoring method based on topology recognition.

[0005] The technical solution adopted by the present invention to solve the technical problem is: a low voltage area system dynamic monitoring method based on topology recognition comprises the following steps:

[0006] S1: time calibration;

[0007] S2: Get 96 points of active power data;

[0008] S3: Monitor the power grid status and determine whether it is necessary to start topology calculation. If necessary, enter S4, otherwise continue monitoring;

[0009] S4: Select the area where slope failure calculation needs to be started for topological calculation;

[0010] S5: The master station compares the calculated topology results with the previous topology results. If there is a difference, it will be updated. If there is no difference but the substation area has a high loss, an abnormal line loss analysis will be performed. The high loss in the substation area means that the system line loss rate in the same period or the daily line loss rate in the substation area of ​​the system used is greater than 7%.

[0011] The master station in S1 sends a clock signal at a time interval of T1 to calibrate the energy controller, and uses the energy controller to broadcast the time calibration command to calibrate the intelligent circuit breakers at all levels in the substation, the substation assessment table, and the substation user table to ensure that the clock synchronization error of all meters is less than 2s. The substation user table in step 1 includes a photovoltaic meter, and the power or active data of the photovoltaic meter is negative.

[0012] Each substation energy controller in S2 collects 96 points of active power data of intelligent circuit breakers at all levels in the substation, substation assessment table, and substation user table at time interval T2 through routing, and reports the data to the main station after aggregating the data.

[0013] In S3, the master station detects the change of the power grid status information at the time interval of T3, and determines whether it is necessary to start the topology calculation. If the topology calculation is required, it enters S4, otherwise it continues to monitor the power grid status.

[0014] If any of the following conditions is met in S3, it is determined that the topology of the substation is likely to be updated and topology calculation needs to be started:

[0015] Condition 1: There are batch adjustments in the substation area, such as line reconstruction, new line addition, etc.;

[0016] Condition 2: There are meter replacements, account cancellations, or new meter additions in the distribution area;

[0017] Condition 3: Users in the area have transfers in and out;

[0018] Condition 4: Replacement of the main meter in the area;

[0019] Condition 5: The 10kV line loss in the substation is abnormal.

[0020] In S4, the master station automatically selects the substation that needs to start topology calculation according to the power grid status to perform topology calculation. The calculation method is as follows:

[0021] S4-1: Group the data of each area according to the area number, i.e., area 1, area 2, ..., area N, and initialize the area number cycle number i=0;

[0022] S4-2: Calculate the total active power values ​​of all measuring devices in area i+1, including intelligent circuit breakers at all levels, area assessment tables, and area user tables, and arrange them in descending order, numbered as measuring device 1 to measuring device M. The total active power value is obtained by directly summing the 96 points of active power data of each measuring device, and initialize the measuring device numbering cycle number j=0;

[0023] S4-3: The 96-point active power data of the measuring device j+1 is used as the current parent node data. The measurement device j+2 to measurement device M are used as the sub-node data to be found. Through the ridge regression algorithm, Solve the coefficient vector Β of measurement device j+2~measurement device M = [β j+2 β j+3 ...β M ] T , where λ is the regularization coefficient, the value range of λ is 0.5-10, and E is the unit matrix;

[0024] S4-4: When the coefficient value of a certain measuring device is in the range of 0.95-1.05, the measuring device is judged to be a child node corresponding to the current parent node, and the corresponding relationship between the parent and child nodes is recorded;

[0025] S4-5: Let j=j+1. If j≤M-1, loop S4-3 to S4-4. If j>M-1, execute S4-6.

[0026] S4-6: According to the correspondence between all parent and child nodes, the topology of the area i+1 is obtained;

[0027] S4-7: Let i=i+1. If i≤N-1, loop S4-2 to S4-6. If i>N-1, the topological relationship of area 1 to area N is obtained.

[0028] The abnormal line loss analysis in S5 includes the following sub-steps:

[0029] S5-1: Calculate the 96-point line loss data v by using the subtraction of the area assessment table and the 96-point active power data of all user meters;

[0030] S5-2: Calculate the correlation coefficient between the active power data u and the line loss data v of all 96 points of the user's electricity meter according to the Pearson correlation calculation formula; the Pearson correlation calculation formula is: Among them, ρ u,v is the Pearson correlation between variable u and variable v, n = 96 is the number of sampling points;

[0031] S5-3: When the coefficient ρ u,vWhen the coefficient is greater than 0.90, the user's meter is judged to be suspected of stealing electricity or inaccurate measurement, and an alarm is issued in the form of an event. If there is no coefficient ρ that meets the condition u,v , then the event alarm will not be executed.

[0032] The value range of T1 is 2 hours to 12 hours.

[0033] The value of T2 is 15 minutes.

[0034] The value of T3 is 1 hour to 24 hours.

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

[0036] The present invention automatically starts topology identification and calculation according to the power grid status. During the topology identification and calculation process, only the electricity or power value of the measuring device needs to be used to sort out the superior-subordinate relationship of the measuring device. This method does not require the installation of additional equipment, does not require an increase in hardware costs, and does not require the main station to set up intelligent circuit breakers at various levels in the substation, substation assessment tables, and substation user table equipment type numbers. The complete topology structure of the substation can be sorted out based on the data, and the difference can be compared based on the topology calculation results to judge the line loss situation, thereby realizing dynamic monitoring. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a flow chart of the present invention;

[0038] Figure 2 This is a flow chart of topology calculation of the present invention;

[0039] Figure 3 This is the topological diagram result of the present invention. DETAILED DESCRIPTION

[0040] The following will be combined with 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 of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] Reference Figure 1-Figure 3 ,The low voltage area system dynamic monitoring method based on topology recognition includes the following steps:

[0042] S1: Time calibration; the master station in S1 sends a clock signal at a time interval of T1 to calibrate the energy controller, and uses the energy controller to broadcast the time calibration command to calibrate the intelligent circuit breakers at all levels in the substation, the substation assessment table, and the substation user table to ensure that the clock synchronization error of all meters is less than 2s. The substation user table in step 1 includes a photovoltaic meter, and the power or active data of the photovoltaic meter is negative. The value range of T1 is 2 hours to 12 hours.

[0043] S2: Obtain 96 points of active power data; each substation energy controller in S2 collects 96 points of active power data of smart circuit breakers at all levels, substation assessment tables, and substation user tables in the substation through routing at time intervals T2, and reports the data to the master station after aggregating the data. The value of T2 is 15 minutes.

[0044] S3: Monitor the state of the power grid and determine whether it is necessary to start topology calculation. If so, enter S4, otherwise continue monitoring; in S3, the master station detects changes in power grid state information at a time interval of T3 to determine whether it is necessary to start topology calculation. If topology calculation is required, enter S4, otherwise continue monitoring the power grid state. The value of T3 is 1 hour to 24 hours.

[0045] If any of the following conditions is met in S3, it is determined that the topology of the substation is likely to be updated and topology calculation needs to be started:

[0046] Condition 1: There are batch adjustments in the substation area, such as line reconstruction, new line addition, etc.;

[0047] Condition 2: There are meter replacements, account cancellations, or new meter additions in the distribution area;

[0048] Condition 3: Users in the area have transfers in and out;

[0049] Condition 4: Replacement of the main meter in the area;

[0050] Condition 5: The 10kV line loss in the substation is abnormal.

[0051] In S4, the master station automatically selects the substation that needs to start topology calculation according to the power grid status to perform topology calculation. The calculation method is as follows:

[0052] S4-1: Group the data of each area according to the area number, i.e., area 1, area 2, ..., area N, and initialize the area number cycle number i=0;

[0053] S4-2: Calculate the total active power values ​​of all measuring devices in area i+1, including intelligent circuit breakers at all levels, area assessment tables, and area user tables, and arrange them in descending order, numbered as measuring device 1 to measuring device M. The total active power value is obtained by directly summing the 96 points of active power data of each measuring device, and initialize the measuring device numbering cycle number j=0;

[0054] S4-3: The 96-point active power data of the measuring device j+1 is used as the current parent node data y. The measurement device j+2 to measurement device M are used as the child node data X to be found. Through the ridge regression algorithm, Solve the coefficient vector Β of measurement device j+2~measurement device M = [β j+2 β j+3 ...β M ] T , where λ is the regular coefficient, the value range of λ is 0.5-10, E is the unit matrix, and a value in the current parent node data y and the child node data X is recorded as It represents the electric quantity or power value of the kth 96-point data of the measuring device n, k=j+2,…96; n=1,…,M;

[0055] S4-4: When the coefficient of measuring device a is β a When the value range is 0.95-1.05, the measuring device a is judged to be a child node corresponding to the current parent node, and the corresponding relationship between the parent and child nodes is recorded, a=1,…M;

[0056] S4-5: Let j=j+1. If j≤M-1, loop S4-3 to S4-4. If j>M-1, execute S4-6.

[0057] S4-6: According to the correspondence between all parent and child nodes, the topology of the area i+1 is obtained;

[0058] S4-7: Let i=i+1. If i≤N-1, loop S4-2 to S4-6. If i>N-1, the topological relationship of area 1 to area N is obtained.

[0059] By dynamically detecting changes in the topology structure, the combing process is automatically started. No signal needs to be injected during the combing process. The topology diagram containing the hierarchical relationship between the electricity meter and each branch node device can be combed out based on the electricity meter and branch node device's electricity or power data.

[0060] S5: The master station compares the calculated topology result with the previous topology result. If there is a difference, it is updated. If there is no difference but the substation area has a high loss, an abnormal line loss analysis is performed. The high loss in the substation area means that the system line loss rate in the same period or the daily line loss rate in the substation area of ​​the mining system is greater than 7%. The abnormal line loss analysis in S5 includes the following sub-steps:

[0061] S5-1: Calculate the 96-point line loss data v by using the subtraction of the area assessment table and the 96-point active power data of all user meters;

[0062] S5-2: Calculate the correlation coefficient between the active power data u and the line loss data v of all 96 points of the user's electricity meter according to the Pearson correlation calculation formula; the Pearson correlation calculation formula is: Among them, ρ u,v is the Pearson correlation between variable u and variable v, n = 96 is the number of sampling points;

[0063] S5-3: When the coefficient ρ u,v When the coefficient is greater than 0.90, the user's meter is judged to be suspected of stealing electricity or inaccurate measurement, and an alarm is issued in the form of an event. If there is no coefficient ρ that meets the condition u,v , then the event alarm will not be executed.

[0064] The above descriptions are only optional embodiments of the present invention, and are not intended to limit the patent scope of the present invention. All equivalent structural changes made using the contents of the present invention's specification and drawings, or directly / indirectly applied in other related technical fields, are included in the patent protection scope of the present invention.

Claims

1. A method for dynamic monitoring of low voltage area system based on topology recognition, characterized in that: The following steps are involved: S1: time calibration; S2: Get 96 points of active power data; S3: Monitor the power grid status and determine whether it is necessary to start topology calculation. If necessary, enter S4, otherwise continue monitoring; S4: Select the area where slope failure calculation needs to be started for topological calculation; S5: Compare the calculated topology results with the previous topology results. If there are differences, update them. If there are no differences but high losses occur in the substation area, perform abnormal line loss analysis.

2. The method for dynamic monitoring of low voltage substation system based on topology recognition according to claim 1 is characterized in that: The master station in S1 sends clock signals at time intervals of T1 to calibrate the energy controller, and uses the energy controller to broadcast the calibration command to calibrate the intelligent circuit breakers at all levels in the substation, the substation assessment table, and the substation user table to ensure that the clock synchronization error of all meters is less than 2s.

3. The method for dynamic monitoring of low voltage substation system based on topology recognition according to claim 1 is characterized in that: Each substation energy controller in S2 collects 96 points of active power data of intelligent circuit breakers at all levels in the substation, substation assessment table, and substation user table at time interval T2 through routing, and reports the data to the main station after aggregating the data.

4. The method for dynamic monitoring of low voltage substation system based on topology recognition according to claim 1 is characterized in that: In S3, the master station detects the change of the power grid status information at the time interval of T3, and determines whether it is necessary to start the topology calculation. If the topology calculation is required, it enters S4, otherwise it continues to monitor the power grid status.

5. The method for dynamic monitoring of low voltage substation system based on topology recognition according to claim 4 is characterized in that: If any of the following conditions is met in S3, it is determined that topology calculation needs to be started: Condition 1: There are batch adjustments in the area; Condition 2: There are meter replacements, account cancellations, or new meter additions in the distribution area; Condition 3: Users in the area have transfers in and out; Condition 4: Replacement of the main meter in the area; Condition 5: The 10kV line loss in the substation is abnormal.

6. The method for dynamic monitoring of low voltage substation system based on topology recognition according to claim 1 is characterized in that: In S4, the master station automatically selects the substation that needs to start topology calculation according to the power grid status to perform topology calculation. The calculation method is as follows: S4-1: Group the data of each area according to the area number, i.e., area 1, area 2, ..., area N, and initialize the area number cycle number i=0; S4-2: Calculate the total active power values ​​of all measuring devices in area i+1, including intelligent circuit breakers at all levels, area assessment tables, and area user tables, and arrange them in descending order, numbered as measuring device 1 to measuring device M. The total active power value is obtained by directly summing the 96 points of active power data of each measuring device, and initialize the measuring device numbering cycle number j=0; S4-3: Take the 96-point active power data of measuring device j+1 as the current parent node data, and take measuring devices j+2 to measuring devices M as the child node data to be found; solve the coefficient vector Β=[β j+2 β j+3 ...β M ] T ; S4-4: When the coefficient value of a certain measuring device is in the range of 0.95-1.05, the measuring device is judged to be a child node corresponding to the current parent node, and the corresponding relationship between the parent and child nodes is recorded; S4-5: Let j=j+1. If j≤M-1, loop S4-3 to S4-4. If j>M-1, execute S4-6. S4-6: According to the correspondence between all parent and child nodes, the topology of the area i+1 is obtained; S4-7: Let i=i+1. If i≤N-1, loop S4-2 to S4-6. If i>N-1, calculate the topological relationship of area 1 to area N.

7. The method for dynamic monitoring of low voltage substation system based on topology recognition according to claim 1 is characterized in that: The abnormal line loss analysis in S5 includes the following sub-steps: S5-1: Calculate the 96-point line loss data v by using the subtraction of the area assessment table and the 96-point active power data of all user meters; S5-2: Calculate the correlation coefficient between the active power data u and the line loss data v of all 96 points of the user's electricity meter according to the Pearson correlation calculation formula; the Pearson correlation calculation formula is: Among them, ρ u,v is the Pearson correlation between variable u and variable v, n = 96 is the number of sampling points; S5-3: When the coefficient ρ u,v When the coefficient is greater than 0.90, the user's meter is judged to be suspected of stealing electricity or inaccurate measurement, and an alarm is issued in the form of an event. If there is no coefficient ρ that meets the condition u,v , then the event alarm will not be executed.

8. The method for dynamic monitoring of low voltage substation system based on topology recognition according to claim 2 is characterized in that: The value range of T1 is 2 hours to 12 hours.

9. The method for dynamic monitoring of low voltage substation system based on topology recognition according to claim 3 is characterized in that: The value of T2 is 15 minutes.

10. The method for dynamic monitoring of low voltage substation system based on topology recognition according to claim 4 is characterized in that: The value of T3 is 1 hour to 24 hours.

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