Single-phase load rate overload treatment method and system for low-voltage transformer area

Abstract

The invention relates to a low-voltage transformer area single-phase load rate overload management method and system. The method comprises the following steps: acquiring a key transformer area needing single-phase load rate overload management and a corresponding data analysis date; collecting phase information of users in key courts and three-phase current curve data of the users at 96 moments under a data analysis date; performing three-phase current unbalance analysis based on the collected data, generating multiple groups of phase modulation schemes, and generating a final commutation suggestion after merging and optimization; issuing a phase modulation suggestion to field phase modulation personnel for field phase modulation; and 5, after the field phase modulation is completed, returning to the step 1, and continuously obtaining the transformer area data for judgment and adjustment. Compared with the prior art, the method has the advantages of reducing the phase modulation frequency, improving the overload management efficiency of the single-phase load rate of the low-voltage transformer area and the like.

Description

Technical Field

[0001] The present invention relates to the field of power supply and distribution technology, and in particular to a method and system for managing single-phase load rate overload in a low-voltage substation. Background Art

[0002] With the development of society and economy, the demand for electricity by users has also increased, and the corresponding requirements for distribution networks have also been raised. Not only the reliability of power supply needs to be ensured, but also the quality of power needs to be guaranteed. However, in actual operation, due to various reasons, the three-phase imbalance in low-voltage substations can cause single-phase load rate overload in low-voltage substations, thus threatening the normal operation of the distribution network. Therefore, power supply companies have strengthened their research on the management of single-phase load rate overload in low-voltage substations and have adopted corresponding management solutions.

[0003] In the process of single-phase load rate overload control in low-voltage substations, the most commonly used control method is to measure the three-phase current during peak power consumption periods, analyze the causes of three-phase imbalance based on user distribution density and power consumption characteristics, and readjust the load distribution in a timely manner, providing technical support for power supply companies.

[0004] However, the current low-voltage substation single-phase load rate overload control technology is limited by the traditional three-phase imbalance control, and there is a problem of frequent manual phase adjustment, which increases the work pressure of on-site personnel. Therefore, how to ensure power supply reliability and quality while reducing the work pressure of on-site personnel and avoid single-phase load rate overload in the substation is an urgent problem that needs to be solved.

[0005] After searching, Chinese invention patent application publication number CN113922395A discloses a method and system for managing three-phase imbalance. The method includes: calculating the self-correlation of the distribution transformer under the low-voltage substation, and determining whether the self-correlation of the distribution transformer is higher than a preset threshold; formulating a single-phase meter phase judgment strategy based on current or voltage calculation for the three-phase imbalance management strategy based on the comparison result of the self-correlation of the distribution transformer and the preset threshold; calculating the Pearson correlation coefficient between the distribution transformer and its subordinate single-phase meter based on the single-phase meter phase judgment strategy; iteratively calculating the current loss of the low-voltage substation by adjusting the user phase, and obtaining a three-phase imbalance management strategy by rapidly reducing the current loss; when the number of iterations of the iterative calculation of the current loss reaches the iteration number threshold or the current loss cannot be reduced, stopping the iterative calculation to output the current three-phase imbalance management strategy under the low-voltage substation, so as to manage the current three-phase imbalance according to the management strategy. This existing patent application suffers from the problem of large phase adjustment workload.

[0006] How to reduce the workload of phase adjustment and thus achieve effective single-phase load rate overload control in low-voltage substations has become a technical problem that needs to be solved. Summary of the Invention

[0007] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and to provide a method and system for controlling single-phase load rate overload in low-voltage substations.

[0008] The purpose of the present invention can be achieved by the following technical solutions:

[0009] According to one aspect of the present invention, a method for managing single-phase load rate overload in a low-voltage area is provided, the method comprising:

[0010] Step 1: Based on the judgment criteria for key substations, obtain the key substations that require single-phase load rate overload control and the corresponding data analysis date;

[0011] Step 2: Collect the phase information of users in key areas and the three-phase current curve data of users at 96 moments on the data analysis date;

[0012] Step 3: Based on the data collected in step 2, perform three-phase current imbalance analysis and generate final commutation recommendations;

[0013] Step 4: Issue the final phase adjustment suggestion to the on-site phase adjustment personnel for on-site phase adjustment;

[0014] Step 5: After the on-site phase adjustment is completed, return to step 1 and continue to obtain substation data to make judgments and adjustments.

[0015] Preferably, the judgment conditions for the key substation are: the load rate of the substation at each moment of a single day is greater than the first threshold, the three-phase current imbalance is greater than the second threshold and the single-phase load rate is greater than the third threshold, and the duration is greater than 1 hour.

[0016] More preferably, the data analysis date is the date of the corresponding data when the key substation determination conditions are met, which is used for three-phase imbalance analysis.

[0017] Preferably, the process of step three includes:

[0018] For the data collected in step 2, the total current of the three-phase ABC users in the substation at 96 moments is calculated respectively, and the current data of the users in the substation on each data analysis date is analyzed to generate phase modulation window period data for multiple dates;

[0019] Based on the phase adjustment window period data and the total current data of the three-phase users in the substation, three-phase imbalance analysis is performed to generate the corresponding phase adjustment plan for each moment;

[0020] The phase adjustment schemes with the same phase adjustment methods in multiple groups are merged and the reasonable phase adjustment schemes are used as alternative phase adjustment schemes.

[0021] More preferably, based on the data collected in the second step, the total current of the ABC three-phase users in the substation at 96 moments is calculated respectively, and the substation load rate, three-phase current imbalance and single-phase load rate at each moment are calculated based on the three-phase current curve data; if the judgment conditions of the key substation are met, the corresponding moment is set as the phase adjustment window period.

[0022] More preferably, the merging process includes:

[0023] For a single phase adjustment scheme where the user commutation ratio exceeds the fourth threshold, further processing is performed, specifically: if the first user commutates from phase A to phase B, and the second user commutates from phase B to phase A, and the current difference between the first user and the second user does not exceed 1 ampere, then the first user and the second user do not commutate;

[0024] After the processing, the user commutation ratio in the phase adjustment scheme is determined again. If the user commutation ratio still exceeds the fourth threshold, the phase adjustment scheme is considered unreasonable; otherwise, the phase adjustment scheme is considered reasonable.

[0025] A reasonable phase adjustment scheme is selected as an alternative phase adjustment scheme.

[0026] More preferably, the process of step three further includes an optimization process, specifically:

[0027] Substitute the alternative phase adjustment scheme into different data analysis dates, and process the user phase and user current data after phase adjustment to obtain the average three-phase imbalance of the alternative phase adjustment scheme for all data analysis dates and the average value of the maximum load rate among the three-phase load rates of ABC at each moment, until all alternative phase adjustment schemes are traversed;

[0028] All alternative phase adjustment schemes are sorted from small to large according to the average three-phase imbalance and the average value of the maximum load rate among the three-phase load rates of ABC at each moment;

[0029] Take the top n groups of alternative phase adjustment schemes and bring them into the user current data of all data analysis dates. Calculate the substation load factor, three-phase current imbalance, and single-phase load factor based on the phase adjustment data of the alternative phase adjustment schemes. If the judgment conditions of the substation are met, the scheme is considered unreasonable and discarded. Otherwise, the scheme is considered reasonable and the top-ranked reasonable scheme is selected as the final phase adjustment recommendation.

[0030] If no reasonable solution exists after verification of all alternative phase adjustment schemes, it is considered that there is no final phase adjustment recommendation for the substation, and it is recommended that the substation capacity be increased or a new substation be added to improve the overload situation of the substation load rate.

[0031] More preferably, the process of calculating the average three-phase imbalance and the average value of the maximum load rate among the ABC three-phase load rates at each moment includes: substituting the alternative phase adjustment scheme into different data analysis dates, calculating the three-phase current imbalance and single-phase load rate at 96 moments of different data analysis dates based on the user phase and user current data after phase adjustment, and summarizing the calculation of the daily average three-phase imbalance and the average value of the maximum load rate among the ABC three-phase load rates at each moment of the day for each data analysis date; then taking the average of the daily average three-phase imbalance and the average value of the maximum load rate among the ABC three-phase load rates at each moment of the day for all data analysis dates, and calculating the average three-phase imbalance of all data analysis dates and the average value of the maximum load rate among the ABC three-phase load rates at each moment of the day for the alternative phase adjustment scheme.

[0032] More preferably, when the average three-phase unbalance is the same as the average value of the maximum load factor among the ABC three-phase load factors at each moment, priority is given to the average value of the maximum load factor among the ABC three-phase load factors at each moment.

[0033] According to another aspect of the present invention, a low-voltage substation single-phase load rate overload management system is provided, comprising a memory and a processor, wherein the memory stores a computer program, and the processor implements the method when executing the program.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] 1) The present invention determines the key substations and data analysis dates by obtaining low-voltage substation models and operating data, and performs three-phase imbalance analysis on users through user current, generating phase adjustment plans for multiple data analysis dates and multiple data moments, and after merging and selecting the best ones, generates final phase adjustment suggestions for on-site phase adjustment. The final phase adjustment suggestions produced greatly reduce the number of phase adjustment users and the number of on-site construction times, thereby reducing the workload of manual phase adjustment to the greatest extent and improving the efficiency of single-phase load rate overload management.

[0036] 2) Based on the traditional three-phase unbalance adjustment scheme, the present invention reduces the amount of analyzed substation data by screening data analysis dates in key substations, speeds up data processing, and reduces the workload of manual phase adjustment.

[0037] 3) The present invention reduces the number of three-phase imbalance analyses and shortens the analysis time by setting a phase adjustment window period; merges multiple phase adjustment schemes to avoid excessive phase switching by actual users on site; sorts the processed data by average three-phase imbalance and maximum load rate, and selects the top n schemes for verification again; selects reasonable schemes as the final phase adjustment recommendations to support on-site phase adjustment; multiple screening and verification are all aimed at reducing the workload of on-site phase adjustment and improving management efficiency.

[0038] 4) The present invention outputs a phase adjustment scheme with the minimum number of phase adjustment users and the minimum number of on-site construction times under the premise of ensuring the three-phase imbalance and single-phase load rate of the substation, which is used for the overload control of the single-phase load rate in the substation, reduces the three-phase imbalance, thereby reducing the single-phase load rate and line loss rate, making the power grid more economical to achieve the purpose of reducing losses, saving energy and increasing distribution reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 Schematic diagram of the process of the single-phase load rate overload control method of the present invention;

[0040] Figure 2 The figure is a flow chart of generating commutation suggestions based on three-phase current imbalance analysis in the present invention. DETAILED DESCRIPTION

[0041] 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 part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0042] Frequent manual phase adjustment is due to the lack of plan calculation and generation. Instead, phase adjustment is performed based on the experience of on-site personnel. However, under uncertain and fluctuating user loads, manual phase adjustment often still results in three-phase imbalance, a drawback of manual phase adjustment. The purpose of this application is to generate an optimal phase adjustment plan that eliminates three-phase imbalance over a period of approximately three months (determined by the different load conditions of summer and winter peaks).

[0043] Example 1

[0044] This embodiment relates to a method for managing single-phase load rate overload in a low-voltage area. Figure 1 As shown, the following steps are included:

[0045] Step 1: Based on the three-phase voltage, three-phase current, active power and reactive power data at the head end of the substation, calculate the load rate, three-phase current imbalance and single-phase load rate of the substation at each moment of the day, and determine whether the judgment conditions of the key substation are met (four conditions are met at the same time: the load rate is greater than the first threshold, the three-phase current imbalance is greater than the second threshold, the single-phase load rate is greater than the third threshold, and the duration is greater than 1 hour); if yes, set the substation as a key substation, and set the date of the corresponding data as the data analysis date.

[0046] The key substations are those that will need to undergo three-phase imbalance analysis and then single-phase load rate overload control.

[0047] The data analysis date is the date corresponding to the data used when performing three-phase imbalance analysis in key substations.

[0048] Step 2: Collect the phase information of users in key substations, and obtain the three-phase current curve data of users at 96 moments on the data analysis date in key substations.

[0049] Step 3: Based on the data from step 2, perform three-phase current imbalance analysis and generate commutation suggestions, such as Figure 2 ,include:

[0050] Step 31, based on the data from the second step, calculate the total current of the ABC three-phase users in the substation at 96 moments respectively, and at the same time calculate the substation load rate, three-phase current imbalance, and single-phase load rate at each moment based on the three-phase current curve data. If the judgment conditions of the key substation are met, these moments are set as phase-adjusting window periods. The phase-adjusting window period is based on performing three-phase imbalance analysis at these moments. The purpose of setting the phase-adjusting window period is to reduce the number of three-phase imbalance analyses and shorten the analysis time. According to the above logic, the current data of users in the substation on each data analysis date is analyzed to generate phase-adjusting window period data for multiple dates. The phase-adjusting window period data includes the data analysis date and the corresponding data time array.

[0051] Step 32: Based on the phase adjustment window data and the total current data of the three-phase users in the substation area, a three-phase imbalance analysis is performed to generate a corresponding phase adjustment plan for each time instant. The phase adjustment plan is a recommended access phase plan for a specific user. The three-phase imbalance analysis method used is prior art and will not be further described in this application.

[0052] Step 33: merge the phase modulation schemes with the same phase modulation methods in the multiple phase modulation schemes to reduce the subsequent analysis time.

[0053] Further analysis is conducted for scenarios where too many users switch phases in a single phase adjustment scheme (for example, the number of users switching phases exceeds 10% of the total users). If the first user switches from phase A to phase B, and the second user switches from phase B to phase A, and the current difference between the first and second users does not exceed 1 ampere, the first and second users will not switch phases. This process aims to reduce the number of phase adjustment users and avoid excessive phase switching on site.

[0054] If after analysis, a single phase adjustment scheme still results in excessive phase switching by users, the scheme is deemed unreasonable, and other reasonable schemes are considered as alternative phase adjustment schemes and analyzed in the next step.

[0055] In step 34, the alternative phase modulation scheme is substituted into different data analysis dates. Based on the phase and current data after phase modulation, the three-phase current imbalance and single-phase load factor are calculated for each of the 96 time points on each data analysis date. The daily average three-phase imbalance and the average of the maximum load factor among the three-phase load factors (A, B, C, and D) at each time point are then calculated for each data analysis date. The daily average three-phase imbalance and the average of the maximum load factor among the three-phase load factors (A, B, C, and D) at each time point are then averaged for all data analysis dates to obtain the average three-phase imbalance and the average of the maximum load factor among the three-phase load factors (A, B, C, and D) at each time point for the alternative phase modulation scheme.

[0056] Step 35 repeats step 34 and loops through all alternative phase adjustment schemes to obtain the average three-phase imbalance for each alternative phase adjustment scheme for all data analysis dates and the average maximum load factor among the three-phase load factors A, B, and C at each time point. All alternative phase adjustment schemes are sorted from smallest to largest based on the average three-phase imbalance and the average maximum load factor among the three-phase load factors A, B, and C at each time point.

[0057] Step 36, take the first n groups (n≥5) of alternative phase adjustment schemes in step 35, and bring them into the user current data of all data analysis dates, calculate the substation load rate, three-phase current imbalance, and single-phase load rate according to the data after phase adjustment of the alternative phase adjustment scheme, if the load rate, three-phase current imbalance, and single-phase load rate are greater than the set threshold, and the duration is greater than 1 hour, then the scheme is considered unreasonable and abandoned. Verify the n groups of alternative phase adjustment schemes in turn. If there is a reasonable scheme after all the alternative phase adjustment schemes are verified, the reasonable scheme is the final phase adjustment recommendation. If there is no reasonable scheme after all the phase adjustment schemes are verified, it is considered that there is no final phase adjustment recommendation for the substation, and it is recommended that the substation increase the substation capacity or add a new substation to improve the substation load rate overload situation. This application does not describe this situation.

[0058] The final phase adjustment recommendation is 1-5 phase adjustment plans, with a maximum of 5 phase adjustment plans and a minimum of 1 phase adjustment plan.

[0059] In this embodiment, the load rate setting threshold is 50%, the three-phase current imbalance setting threshold is 25%, and the single-phase load rate setting threshold is 100%.

[0060] Step 4: After the final phase adjustment suggestion is generated, it is sent to the on-site phase adjustment personnel for on-site phase adjustment.

[0061] During on-site phase adjustment, if some users in the phase adjustment proposal are not capable of phase adjustment, feedback will be provided. The phase adjustment plan will be adjusted and the new phase adjustment plan results will be verified. If the results are reasonable, on-site phase adjustment will be carried out according to the new phase adjustment plan. If the results are unreasonable, the user's phase will be locked, imbalance analysis will be conducted again, and new phase adjustment recommendations will be issued for on-site phase adjustment.

[0062] Step 5: After commutation is complete, return to Step 1 and continue acquiring the three-phase voltage, three-phase current, active power, and reactive power data at the substation headend. Calculate the substation load factor, three-phase current imbalance, and single-phase load factor at each time of the day. Verify that the load factor, three-phase current imbalance, and single-phase load factor are greater than the corresponding set thresholds and persist for more than one hour.

[0063] Example 2

[0064] This embodiment also relates to a method for managing single-phase load rate overload in a low-voltage area, comprising the following steps:

[0065] Step 1: After obtaining the substation model and substation operation data, perform substation status analysis and calculation, which mainly includes the following steps:

[0066] 11. Based on the three-phase voltage, three-phase current and power (active power, reactive power) data of the substation head end 96, calculate the substation load rate, three-phase current imbalance and single-phase load rate at each time of the day.

[0067] Data can be collected during either the summer or winter periods of high load, and phase change before winter or summer can be implemented for a single transformer substation. Single-phase load factor overload control is not considered for the spring and autumn periods of stable load.

[0068] 12. Based on the analysis results of the substation status, screen out substations where the load rate is greater than the first threshold (for example, 50%), the three-phase imbalance is greater than the second threshold (for example, 25%), and the single-phase load rate is greater than the third threshold (for example, 100%) and lasts for more than 1 hour as key substations, and the date of the corresponding data is used as the data analysis date.

[0069] Step 2: After obtaining the key substation, collect information for the key substation to obtain the phase information of users in the key substation and the current curve data of users in the substation on the corresponding data analysis date.

[0070] Step 3: After the key substations are funded, the single-phase load rate overload control analysis and calculation of the low-voltage substations is carried out, which mainly includes the following steps:

[0071] 31. Based on the user phase and the user's current data at 96 moments, calculate the total current of phase A users, phase B users, and phase C users in the substation at 96 moments.

[0072] Based on the total current of ABC three-phase users, the load rate of the substation, the three-phase current imbalance, and the single-phase load rate are calculated at each moment.

[0073] The moment when the load rate is greater than 50%, the three-phase imbalance is greater than 25%, and the single-phase load rate is greater than 100% for more than 1 hour is selected as the phase adjustment window period.

[0074] 32. Take the data moments of different window periods on different data analysis dates as phase adjustment moments, and conduct three-phase imbalance analysis of the substation area based on these moments and the user currents at the corresponding moments.

[0075] 33. After the three-phase imbalance analysis is completed, multiple phase adjustment schemes are generated for different phase adjustment moments, and the schemes with exactly the same phase adjustment methods are merged.

[0076] Further analysis shows that if too many users switch phases in a single phase adjustment scheme (the number of users switching phases exceeds a set ratio of total users, such as 10%), if the first user switches from phase A to phase B, and the second user switches from phase B to phase A, and the current difference between the first and second users does not exceed 1 ampere, then the first and second users do not switch phases.

[0077] After analysis, if there is still a situation where users in a single phase adjustment scheme have too many phase changes, then the phase adjustment scheme is considered unreasonable and other phase adjustment schemes are selected as alternative phase adjustment schemes.

[0078] 34. Substitute the alternative phase adjustment schemes into different data analysis dates in turn, calculate the substation load rate, three-phase current imbalance, and single-phase load rate at 96 moments on different data analysis dates, and count the daily average three-phase imbalance, daily maximum three-phase imbalance, the average maximum load rate among the ABC three-phase load rates at each moment of the day, and the daily maximum single-phase load rate on each data analysis date.

[0079] 35. For each alternative phase adjustment scheme, average the daily average three-phase imbalance across different data analysis dates and the average maximum load factor among the three-phase load factors A, B, and C at each time point in the day. This results in the average three-phase imbalance across all data analysis dates and the average maximum load factor among the three-phase load factors A, B, and C at each time point for each alternative phase adjustment scheme. The alternative phase adjustment scheme with the smallest of these two values ​​is considered the optimal phase adjustment scheme. If these two values ​​are the same, the average maximum load factor among the three-phase load factors A, B, and C at each time point is prioritized.

[0080] 36. Verify whether there is a situation where the load rate is greater than 50%, the three-phase imbalance is greater than 25%, and the single-phase load rate is greater than 100% for more than 1 hour after phase adjustment according to the optimal phase adjustment plan.

[0081] If the optimal phase adjustment scheme does not exist, the final phase adjustment recommendation is used. If the optimal phase adjustment scheme does exist, the final phase adjustment recommendation cannot be generated for this substation. It is recommended that the substation capacity be increased or a new substation be added.

[0082] Step 4: After the final phase adjustment suggestion is generated, the final phase adjustment suggestion is issued to the substation for on-site phase adjustment.

[0083] During on-site phase adjustment, if some users in the phase adjustment proposal are not capable of phase adjustment, feedback will be provided. The phase adjustment plan will be adjusted and the new phase adjustment plan results will be verified. If the results are reasonable, on-site phase adjustment will be carried out according to the new phase adjustment plan. If the results are unreasonable, the phase of the user will be locked, and the three-phase four-level imbalance analysis will be conducted again. A new phase adjustment plan will be issued for on-site phase adjustment.

[0084] Step 5: After commutation is complete, continuously obtain the three-phase voltage, three-phase current, active power, and reactive power data at the substation headend. Calculate the substation load factor, three-phase current imbalance, and single-phase load factor at each time of the day. Verify whether the load factor is greater than 50%, the three-phase imbalance is greater than 25%, or the single-phase load factor is greater than 100% for more than one hour.

[0085] Example 3

[0086] This embodiment also relates to a low-voltage substation single-phase load rate overload management system, which includes a central processing unit (CPU), a memory and a processor. The memory stores instructions for the processor to implement the above-mentioned low-voltage substation single-phase load rate overload management method. The central processing unit can perform various appropriate actions and processes according to the instructions in the memory.

[0087] There is an interface between this system and the business operation middle-office system, through which the substation model data is obtained from the business operation middle-office system, including substation name, affiliated line, feeder segment model, feeder segment length, feeder segment line system, user phase, down-line model, down-line length and topological relationship and other information.

[0088] There is an interface between the system and the data middle platform, through which the low-voltage substation operation data of the marketing procurement system is obtained from the data middle platform. The low-voltage substation operation data includes the three-phase voltage, three-phase current and power data at the head end of the substation and the voltage, current and power data of the substation users.

[0089] If user identities cannot be obtained from the business operation center system, the system provides a user import function for the area, which allows users to import information such as area name and user identity through Excel. During the model acquisition process, user data that cannot be obtained from the business operation center system can be obtained by importing data.

[0090] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and such modifications or substitutions are intended to be within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be subject to the scope of protection of the claims.

Claims

1. A method for managing single-phase load rate overload in low-voltage areas, characterized in that: The method includes: Step 1: Based on the judgment criteria for key substations, obtain the key substations that require single-phase load rate overload control and the corresponding data analysis date; Step 2: Collect the phase information of users in key areas and the three-phase current curve data of users at 96 moments on the data analysis date; Step 3: Based on the data collected in step 2, perform three-phase current imbalance analysis, generate multiple phase adjustment schemes, and combine and optimize the schemes to generate the final phase change recommendation. Step 4: Issue the final phase adjustment suggestion to the on-site phase adjustment personnel for on-site phase adjustment; Step 5: After the on-site phase adjustment is completed, return to step 1 and continue to obtain substation data to make judgments and adjustments.

2. A method for managing single-phase load rate overload in a low-voltage area according to claim 1, characterized in that: The judgment conditions for the key substation are: the load rate of the substation at each moment of a single day is greater than the first threshold, the three-phase current imbalance is greater than the second threshold, the single-phase load rate is greater than the third threshold, and the duration is greater than 1 hour.

3. A method for managing single-phase load rate overload in a low-voltage area according to claim 2, characterized in that: The data analysis date is the date of the corresponding data when the key substation judgment conditions are met, and is used for three-phase imbalance analysis.

4. A method for managing single-phase load rate overload in a low-voltage area according to claim 1, characterized in that: The process of step three includes: For the data collected in step 2, the total current of the three-phase ABC users in the substation at 96 moments is calculated respectively, and the current data of the users in the substation on each data analysis date is analyzed to generate phase modulation window period data for multiple dates; Based on the phase adjustment window period data and the total current data of the three-phase users in the substation, three-phase imbalance analysis is performed to generate the corresponding phase adjustment plan for each moment; The phase adjustment schemes with the same phase adjustment methods in multiple groups are merged and the reasonable phase adjustment schemes are used as alternative phase adjustment schemes.

5. A method for managing single-phase load rate overload in a low-voltage area according to claim 4, characterized in that: Based on the data collected in the second step, the total current of the ABC three-phase users in the substation at 96 moments is calculated respectively. At the same time, the substation load rate, three-phase current imbalance and single-phase load rate at each moment are calculated based on the three-phase current curve data. If the judgment conditions of the key substation are met, the corresponding moment will be set as the phase adjustment window period.

6. A method for managing single-phase load rate overload in a low-voltage area according to claim 4, characterized in that: The merging process includes: For a single phase adjustment scheme where the user commutation ratio exceeds the fourth threshold, further processing is performed, specifically: if the first user commutates from phase A to phase B, and the second user commutates from phase B to phase A, and the current difference between the first user and the second user does not exceed 1 ampere, then the first user and the second user do not commutate; After the processing, the user commutation ratio in the phase adjustment scheme is determined again. If the user commutation ratio still exceeds the fourth threshold, the phase adjustment scheme is considered unreasonable; otherwise, the phase adjustment scheme is considered reasonable. A reasonable phase adjustment scheme is selected as an alternative phase adjustment scheme.

7. A method for managing single-phase load rate overload in a low-voltage area according to claim 4, characterized in that: The process of step 3 also includes an optimization process, specifically: Substitute the alternative phase adjustment scheme into different data analysis dates, and process the user phase and user current data after phase adjustment to obtain the average three-phase imbalance of the alternative phase adjustment scheme for all data analysis dates and the average value of the maximum load rate among the three-phase load rates of ABC at each moment, until all alternative phase adjustment schemes are traversed; All alternative phase adjustment schemes are sorted from small to large according to the average three-phase imbalance and the average value of the maximum load rate among the three-phase load rates of ABC at each moment; Take the top n groups of alternative phase adjustment schemes and bring them into the user current data of all data analysis dates. Calculate the substation load factor, three-phase current imbalance, and single-phase load factor based on the phase adjustment data of the alternative phase adjustment schemes. If the judgment conditions of the substation are met, the scheme is considered unreasonable and discarded. Otherwise, the scheme is considered reasonable and the top-ranked reasonable scheme is selected as the final phase adjustment recommendation. If no reasonable solution exists after verification of all alternative phase adjustment schemes, it is considered that there is no final phase adjustment recommendation for the substation, and it is recommended that the substation capacity be increased or a new substation be added to improve the overload situation of the substation load rate.

8. A method for managing single-phase load rate overload in a low-voltage area according to claim 7, characterized in that: The process of calculating the average three-phase imbalance and the average value of the maximum load rate among the ABC three-phase load rates at each moment includes: substituting the alternative phase adjustment scheme into different data analysis dates, calculating the three-phase current imbalance and single-phase load rate at 96 moments on different data analysis dates based on the user phase and user current data after phase adjustment, and summarizing and calculating the daily average three-phase imbalance and the average value of the maximum load rate among the ABC three-phase load rates at each moment of the day for each data analysis date; then taking the average of the daily average three-phase imbalance and the average value of the maximum load rate among the ABC three-phase load rates at each moment of the day for all data analysis dates, and calculating the average three-phase imbalance of all data analysis dates and the average value of the maximum load rate among the ABC three-phase load rates at each moment of the day for the alternative phase adjustment scheme.

9. A method for managing single-phase load rate overload in a low-voltage area according to claim 7, characterized in that: When the average three-phase unbalance is the same as the average value of the maximum load rate among the ABC three-phase load rates at each moment, priority is given to the average value of the maximum load rate among the ABC three-phase load rates at each moment.

10. A low-voltage area single-phase load rate overload management system, comprising a memory and a processor, wherein the memory stores a computer program, characterized in that: When the processor executes the program, the method according to any one of claims 1 to 9 is implemented.

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