Accurate control method for load of incremental power distribution network

Abstract

The invention discloses an incremental power distribution network load accurate control method, and belongs to the technical field of power grid coordination. According to the method, the problem that the increment power distribution network load is difficult to accurately regulate and control due to the fact that the operation risk of the power grid after energy storage access is difficult to evaluate in the prior art is solved, the increment power distribution network load is compared with the low-voltage load shedding threshold value, the low-voltage load shedding operation is performed on the load in combination with the priority of each intelligent power distribution terminal, and the power distribution network load can be accurately regulated and controlled. The load of the power distribution network can be automatically reduced when the frequency or the voltage is abnormal, and the stable operation of the incremental power distribution network is ensured; a load control scheme is formulated to ensure that electricity limiting measures are taken when incremental power distribution network load control is implemented, so that the influence on users is reduced to the greatest extent; and the operation risk of the power grid after the energy storage access is evaluated in advance, the matching scheme of the new energy, the energy storage and the load in different time periods of the region under different output modes is analyzed, the optimal source grid load storage control strategy is provided, and the flexible control of the light storage load is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of power grid coordination, and in particular to a method for precise control of incremental distribution network load. Background Art

[0002] The so-called incremental distribution network refers to the newly added distribution network in addition to the distribution network already built by the power grid company; the power grid in the power system is layered according to the voltage level, the transmission network belongs to the high voltage level, and the distribution network belongs to the low voltage level. Generally, the power grid with a voltage level of 220 (330) kilovolts or above is the transmission network, and the power grid below is the distribution network; and the "incremental" distribution network corresponds to the concept of "stock". In recent years, with the explosive growth of the scale of installed capacity of new energy power generation and the access of charging piles and energy storage facilities, the role and tasks of the distribution network have undergone tremendous changes; the construction of new energy storage, as an important part of building a new power system, is of great significance to promoting the green transformation of energy, ensuring power supply safety, and improving the consumption of new energy; the relevant supporting policies for the coordinated development of new energy storage and new energy are constantly being improved, laying the foundation for the innovative application of new energy storage technology and high-quality development.

[0003] However, as new energy storage and renewable energy sources are connected to the regional power grid, it is difficult to assess the operational risks of the power grid after the energy storage is connected. At the same time, it is difficult to accurately control the incremental distribution network load, thereby reducing the coordination function of the existing incremental distribution network load.

[0004] Therefore, the existing needs are not met, and we propose a precise control method for the incremental distribution network load. Summary of the invention

[0005] The purpose of the present invention is to provide a precise control method for the load of an incremental distribution network. By comparing the load of the incremental distribution network with the low-voltage load reduction threshold, and combining the priority of each intelligent distribution terminal, the load is subjected to low-voltage load reduction operation, which helps the distribution network to automatically reduce the load when the frequency or voltage is abnormal, and ensure the stable operation of the incremental distribution network; formulate a load control plan to ensure that power-limiting measures are taken when implementing the load control of the incremental distribution network to minimize the impact on users; and conduct an advance assessment of the operating risks of the power grid after the energy storage is connected, analyze the coordination of new energy with energy storage and regional loads in different time periods under different output modes, propose the optimal source-grid-load-storage control strategy, realize flexible control of light-storage-load, and solve the problems raised in the above-mentioned background technology.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] The incremental distribution network load precise control method comprises the following steps:

[0008] S1. Establish an incremental distribution network load management system to obtain and analyze the incremental distribution network load information in real time based on the intelligent distribution terminal, including: the change trend, peak value and valley value of the incremental distribution network load, and accurately predict the incremental distribution network load change;

[0009] S2. Establish the priority of each smart distribution terminal, calculate the comprehensive score of all branch loads of the smart distribution terminal according to the total amount of incremental distribution network loads of each level uploaded by the smart distribution terminal, and obtain the priority of each smart distribution terminal according to the score ranking;

[0010] S3. Establish a low-frequency and low-voltage load reduction system. Based on the total load of each level of incremental distribution network uploaded by the intelligent distribution terminal and the priority of each intelligent distribution terminal, pre-build, enter and adjust the low-frequency and low-voltage load reduction plan of the incremental distribution network load to achieve low-frequency load reduction operation on the incremental distribution network load;

[0011] S4. Establish an accident power restriction and new energy grid connection safety and stability control system, formulate a load control plan through the accident power restriction subsystem, ensure that power restriction measures are taken when implementing incremental distribution network load control, and minimize the impact on users; also through the mutual cooperation of the stabilization control master station, stabilization substation and terminal station in the new energy grid connection safety and stability control subsystem, the controllable loads of energy storage, photovoltaic power stations and substations are included in the control master station to achieve flexible and precise load control;

[0012] S5. Establish a coordinated control system for photovoltaic, storage and load, conduct an early assessment of the operational risks of the power grid after the access of energy storage, and carry out optimization analysis of the safety and stability control strategy after the access of energy storage, as well as an economic assessment of commercial operation; analyze the coordination of new energy with energy storage and regional loads at different time periods under different output modes, propose the optimal source-grid-load-storage control strategy, and realize flexible control of photovoltaic, storage and load.

[0013] Furthermore, the method further comprises the following steps:

[0014] S6. Establish an information interaction platform, and use the wireless transmission network as the transmission medium to enable data interaction between the incremental distribution network load management system, intelligent distribution terminals, low-frequency and low-voltage load reduction system, and emergency power restriction and new energy grid connection safety and stability control systems. Ensure that data interfaces are developed between the systems to achieve linkage and optimize the incremental distribution network load control strategy.

[0015] Further, after the incremental distribution network load management system is established in S1, the following steps are included:

[0016] Collect multiple sets of historical incremental distribution network load information, clean and normalize the historical incremental distribution network load information; use the multiple sets of historical incremental distribution network load information as sample sets, and divide them into multiple sets of training sets and test sets;

[0017] Construct an incremental distribution network load forecasting model, import the training set into the incremental distribution network load forecasting model for training, and output the training results; then import the test set into the incremental distribution network load forecasting model for testing, and output the test results; compare the two results to ensure that the test results are consistent with the training results; then optimize and iterate the incremental distribution network load forecasting model according to different groups of training sets and test sets to ensure the accuracy of the incremental distribution network load forecasting model early warning.

[0018] Furthermore, after the incremental distribution network load information is acquired and analyzed in real time according to the intelligent distribution terminal in S1, the following steps are included:

[0019] The incremental distribution network load information is cleaned and normalized, the preprocessed incremental distribution network load information is imported into the incremental distribution network load early warning model for prediction, and then the current incremental distribution network load prediction result is output, and the current incremental distribution network load prediction result is uploaded to the information interaction platform for data interaction based on the wireless transmission network.

[0020] Furthermore, the calculation of the comprehensive scores of all branch loads of the intelligent distribution terminal in S2 specifically includes the following steps:

[0021] Classify the loads in the incremental distribution network and divide them into primary loads, secondary loads, tertiary loads or industrial loads, commercial loads, and residential loads according to the importance of the loads or the power consumption characteristics of the loads;

[0022] Based on the total amount of incremental distribution network load at each level uploaded by each smart distribution terminal, load calculation is performed according to the total capacity of the smart distribution terminal, the operating conditions of the smart distribution terminal and the power supply capacity of the power grid, and the load information of each smart distribution terminal is obtained. Combined with the load category of each smart distribution terminal, the priority of each smart distribution terminal is established.

[0023] Furthermore, the S3 pre-constructs, enters and adjusts the incremental distribution network load low-frequency and low-voltage load reduction plan, which specifically includes the following steps:

[0024] According to the total load of each level of incremental distribution network uploaded by the smart distribution terminal, a low-frequency and low-voltage load reduction threshold is preset to determine whether the load information of the incremental distribution network exceeds the threshold range. If it does not exceed the threshold range, no low-frequency load reduction operation is performed; if it exceeds the threshold range, combined with the priority of each smart distribution terminal, it is determined to cut off the load of the smart distribution terminal of a certain load category, and based on this, a low-frequency and low-voltage load reduction plan for the incremental distribution network is formulated to restore the frequency balance of the incremental distribution network; among them, the low-frequency and low-voltage load reduction plan for the incremental distribution network includes at least three or more.

[0025] Furthermore, the S3 pre-constructs, enters and adjusts the incremental distribution network load low-frequency and low-voltage load reduction plan, and also includes the following steps:

[0026] After formulating the low-frequency and low-voltage load shedding plan for the incremental distribution network load, the low-frequency and low-voltage load shedding plan for the incremental distribution network load is entered into the low-frequency and low-voltage load shedding system through the human-machine module in the low-frequency and low-voltage load shedding system, and the low-frequency and low-voltage load shedding plan for the incremental distribution network load is rehearsed. According to the rehearsal results, the deficiencies of the plan are adjusted in time to avoid grid operation errors.

[0027] Further, after the low-frequency and low-voltage load reduction plan for the incremental distribution network load is pre-built, entered and adjusted in S3, the following steps are included:

[0028] The total load of each level of incremental distribution network is calculated through the real-time data of incremental distribution network load uploaded by each intelligent distribution terminal. The low-frequency and low-voltage load reduction scheme of the entered incremental distribution network load is judged and selected according to the current total load of the incremental distribution network, and a standard low-frequency and low-voltage automatic load shedding scheme report is generated. The automatic load shedding function in the low-frequency and low-voltage load shedding system is controlled to control the switching or closing of part of the load equipment in the incremental distribution network, so as to realize the low-frequency load shedding operation of the incremental distribution network load.

[0029] Furthermore, in the new energy grid-connected safety and stability control subsystem in S4, the stability control main station is located in the hub substation or power plant, and is responsible for aggregating information, forming control strategies and sending control commands; the stability control substation is located in the important substation or power plant, and is responsible for collecting information and sending it to the main station; the terminal station executes the control commands and provides feedback, and ensures the stability and safety of new energy power generation when connected to the grid through real-time monitoring and control.

[0030] Furthermore, the light-storage-load coordination control system is established in S5, which specifically includes the following steps:

[0031] Construct an energy storage control model and a new energy access model, import the energy storage, photovoltaic power station and controllable load information of each substation included in the control master station into the energy storage control model and the new energy access model for drills, analyze the transient safety and stability characteristics of the power grid, assess the operating risks of the power grid after energy storage access in advance, and optimize the power grid safety and stability control strategy based on the analysis results.

[0032] Furthermore, the comprehensive scores of all branch loads of the intelligent distribution terminal are calculated, including:

[0033] Obtain the load change curve of each branch load of the intelligent power distribution terminal, and determine the peak power consumption period parameters and valley power consumption period parameters of each branch load according to the load change curve;

[0034] Respectively obtain multiple power consumption indicators of each branch load under power consumption peak time period parameters and power consumption valley time period parameters;

[0035] Determine the electricity user based on the electricity consumption index, determine the load source characteristics based on the electricity user, and determine the strong correlation characteristics of each branch load based on the load source characteristics;

[0036] Acquire the modification attribute of the strongly correlated feature, and determine the modification subject of the modification attribute, wherein the modification subject includes: natural and artificial;

[0037] Determine the peak-cutting potential value or valley-flattening potential value of the strongly correlated feature according to the modified subject;

[0038] Determine the load variation range of each branch load according to the peak shaving potential value or the valley leveling potential value, and determine the load regulation score of each branch load according to the load variation range;

[0039] The effective static response load and the effective dynamic response load of each branch load are extracted respectively, and the demand response settlement score of each branch load is determined according to the effective static response load and the effective dynamic response load;

[0040] Determining a load supply score for each branch load based on the demand response settlement score;

[0041] Obtaining the grid topology structure of each branch load, determining the load loss factor according to the grid topology structure, and determining the load loss ratio of each branch load according to the load loss factor, grid data, and a preset grid utilization efficiency evaluation index;

[0042] The load loss score of each branch load is determined according to the load loss ratio, and the comprehensive score of all branch loads of the intelligent distribution terminal is calculated according to the load loss score, load supply score and load regulation score and their respective preset weights.

[0043] Furthermore, before obtaining the priority of each intelligent power distribution terminal according to the ranking of the scores, the following steps are also included:

[0044] Obtain the changes in the operating parameters of each intelligent distribution terminal when the branch load is working, and construct the operating disturbance linearization matrix of each intelligent distribution terminal according to the changes in the operating parameters;

[0045] Obtain the minimum characteristic root of each intelligent distribution terminal under the current working condition according to the working condition disturbance linearization matrix;

[0046] The minimum characteristic root of each intelligent power distribution terminal under standard working conditions is obtained, and the working condition stability maintenance coefficient of each intelligent power distribution terminal is calculated according to the minimum characteristic root of each intelligent power distribution terminal under current working conditions and the minimum characteristic root under standard working conditions:

[0047]

[0048] Among them, S i is represented by the operating stability maintenance coefficient of the i-th intelligent distribution terminal, μ is represented by the linear load limit hyperparameter, and D 1i It is represented as the minimum characteristic root of the i-th intelligent distribution terminal under the current working condition, D 2i It is expressed as the minimum characteristic root of the i-th intelligent distribution terminal under standard working conditions, A i It is expressed as the maintenance coefficient of the i-th intelligent distribution terminal, α is the influence factor of the operating stability margin of the intelligent distribution terminal on the fluctuation degree of the load state variable, F i represents the number of branch loads of the i-th intelligent distribution terminal, j represents the j-th branch load, Q 1j Expressed as the maximum load of the j-th branch load, Q 2j It is expressed as the minimum load of the i-th branch load;

[0049] The priority evaluation weight of the working condition stability maintenance coefficient of the intelligent power distribution terminal and the priority evaluation weight of the comprehensive score of the branch load of each intelligent power distribution terminal are respectively set;

[0050] All intelligent distribution terminals are prioritized based on the set weights, the operating stability maintenance coefficient of each intelligent distribution terminal, and the score ranking.

[0051] Compared with the prior art, the present invention has the following beneficial effects:

[0052] The present invention establishes an incremental distribution network load management system, a low-frequency and low-voltage load reduction system, an accident power restriction and a stability system, and utilizes a wireless communication network to realize data linkage, thereby enhancing the understanding of the actual load situation of the incremental distribution network; compares the incremental distribution network load with a preset low-voltage load reduction threshold, and combines the priority of each intelligent distribution terminal to realize low-voltage load reduction operation on the incremental distribution network load while minimizing the impact on users, which helps to automatically reduce the load when the frequency or voltage of the incremental distribution network is abnormal, thereby ensuring the stable operation of the incremental distribution network; at the same time, a load control plan is formulated to ensure that power restriction measures are taken when implementing the incremental distribution network load control to minimize the impact on users; and the operation risk of the power grid after the energy storage is connected is evaluated in advance, and the optimization analysis of the safety and stability control strategy after the energy storage is connected and the economic evaluation of commercial operation are carried out; the coordination plan of new energy with energy storage and load in different periods of time in different output modes is analyzed, and the optimal source-grid-load-storage control strategy is proposed to realize flexible control of light-storage-load. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 The figure is a flow chart of the intelligent inspection method for passenger documents of the present invention. DETAILED DESCRIPTION

[0054] The following will be combined with 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.

[0055] In order to solve the current technical problem that it is difficult to assess the operation risk of the power grid after the new energy storage and new energy are connected to the regional power grid, and it is difficult to accurately control the load of the incremental distribution network, thereby reducing the load coordination function of the existing incremental distribution network, please refer to Figure 1 , this embodiment provides the following technical solutions:

[0056] In this embodiment, taking the incremental distribution network as an example of the country's first batch of incremental distribution network services, 4 220kV substations have been built. The current power load is about 1 million kilowatts. The users in the region are mainly petrochemical enterprises with continuous production, with high load density and stable load. At the same time, the incremental distribution network responds to the dual carbon goals and carries out the construction of new energy projects. Currently, 4 110kV photovoltaic booster stations have been built and put into operation, with a total installed capacity on the DC side of 285MW.

[0057] The incremental distribution network load precise control method comprises the following steps:

[0058] S1. Establish an incremental distribution network load management system, obtain and analyze the incremental distribution network load information in real time based on the intelligent distribution terminal, including: the change trend, peak value and valley value of the incremental distribution network load, and accurately predict the incremental distribution network load change; before making an accurate prediction, the following operations need to be performed in advance, specifically including the following steps:

[0059] Collect multiple groups of historical incremental distribution network load information, clean and normalize the historical incremental distribution network load information to ensure the validity and authenticity of the information data; use multiple groups of historical incremental distribution network load information as sample sets, and divide them into multiple training sets and test sets; specifically, collect multiple groups of incremental distribution network load information in Xuwei New District as sample data, pre-process them and divide them into sample sets, and use the two divided data as feature sets for training and testing the incremental distribution network load prediction model, and continuously update and iterate the incremental distribution network load prediction model according to the subsequent continuously updated incremental distribution network load information to ensure the accuracy and validity of the incremental distribution network load prediction model.

[0060] Construct an incremental distribution network load prediction model, import the training set into the incremental distribution network load prediction model for training, and output the training results; then import the test set into the incremental distribution network load prediction model for testing, and output the test results; compare the two results to ensure that the test results are consistent with the training results; then optimize and iterate the incremental distribution network load prediction model according to different groups of training sets and test sets to ensure the accuracy of the incremental distribution network load prediction model warning; specifically, import the training set into the incremental distribution network load prediction model for training to establish the characteristic points of the incremental distribution network load prediction model; then import a corresponding set of test sets into the trained incremental distribution network load prediction model for testing to verify the accuracy of the output results of the incremental distribution network load prediction model; after the test results currently output by the incremental distribution network load prediction model are consistent with the training results, the optimized incremental distribution network load prediction model is obtained, and then the incremental distribution network load prediction model is put into use for the current accurate prediction of the incremental distribution network load change.

[0061] After the incremental distribution network load prediction model is successfully constructed and trained, the model is put into use at the current stage. Specifically, after the incremental distribution network load information is acquired and analyzed in real time according to the intelligent distribution terminal, the following steps are included:

[0062] The incremental distribution network load information is cleaned and normalized, the preprocessed incremental distribution network load information is imported into the incremental distribution network load early warning model for prediction, and then the current incremental distribution network load prediction result is output, and the current incremental distribution network load prediction result is uploaded to the information interaction platform based on the wireless transmission network for data interaction; specifically, the incremental distribution network load information currently obtained is preprocessed, imported into the optimized incremental distribution network load prediction model for prediction processing, and the prediction result is output, so as to obtain the prediction result of the current incremental distribution network load change, and make corresponding load control strategy based on the prediction result.

[0063] S2. Establish the priority of each smart distribution terminal, calculate the comprehensive score of all branch loads of the smart distribution terminal according to the total amount of incremental distribution network loads of each level uploaded by the smart distribution terminal, and obtain the priority of each smart distribution terminal according to the score sorting; wherein, calculating the comprehensive score of all branch loads of the smart distribution terminal specifically includes the following steps:

[0064] The loads in the incremental distribution network are classified into primary load, secondary load, tertiary load or industrial load, commercial load and residential load according to their importance or power consumption characteristics. Specifically, by setting priorities, it helps to give priority to key loads when controlling the loads of the incremental distribution network, such as emergency command and disposal departments, radio, television and other users related to safety and social order.

[0065] Based on the total amount of incremental distribution network load at each level uploaded by each smart distribution terminal, load calculation is performed according to the total capacity of the smart distribution terminal, the operation status of the smart distribution terminal and the power supply capacity of the power grid, and the load information of each smart distribution terminal is obtained. The priority of each smart distribution terminal is established in combination with the load category to which each smart distribution terminal belongs;

[0066] For example, in this embodiment, the Xuwei New Area can be divided into industrial load, commercial load, and residential load according to its power load attributes. The areas with more power equipment and denser population among the industrial load, commercial load, and residential load are further classified as the highest load level, the areas with power equipment and population second only to the previous level are classified as the middle load level, and the areas with fewer power equipment and sparser population are classified as the lowest load level. Therefore, according to the above-mentioned load priority allocation, when performing load control, starting from the lowest load level, the load is cut off preferentially at the substation or intelligent distribution terminal that affects the least users, thereby ensuring that the incremental distribution network load is accurately controlled while minimizing the impact on users.

[0067] S3. Establish a low-frequency and low-voltage load reduction system. Based on the total amount of incremental distribution network loads at each level uploaded by the intelligent distribution terminal and the priority of each intelligent distribution terminal, pre-build, enter and adjust the low-frequency and low-voltage load reduction plan for the incremental distribution network load to achieve low-frequency load reduction operations on the incremental distribution network load; wherein, pre-build, enter and adjust the low-frequency and low-voltage load reduction plan for the incremental distribution network load, specifically including the following steps:

[0068] A low-frequency and low-voltage load shedding threshold is preset based on the total load of each level of incremental distribution network uploaded by the smart distribution terminal to determine whether the load information of the incremental distribution network exceeds the threshold range. If it does not exceed the threshold range, no low-frequency load shedding operation is performed; if it exceeds the threshold range, combined with the priority of each smart distribution terminal, it is determined to cut off the load of the smart distribution terminal of a certain load category, and based on this, a low-frequency and low-voltage load shedding plan for the incremental distribution network load is formulated to restore the frequency balance of the incremental distribution network; among them, the low-frequency and low-voltage load shedding plan for the incremental distribution network load includes at least three or more; specifically, by configuring the low-frequency and low-voltage automatic load shedding function for the smart distribution terminal, it is helpful to automatically reduce the load when the frequency or voltage of the incremental distribution network is abnormal, so as to ensure the stable operation of the incremental distribution network; once it is decided to implement load shedding, the low-frequency and low-voltage load shedding system will cut off part of the load in a predetermined order.

[0069] After formulating the low-frequency and low-voltage load shedding plan for the incremental distribution network load, the low-frequency and low-voltage load shedding plan for the incremental distribution network load is entered into the low-frequency and low-voltage load shedding system through the human-machine module in the low-frequency and low-voltage load shedding system, and the low-frequency and low-voltage load shedding plan for the incremental distribution network load is rehearsed. According to the rehearsal results, the shortcomings of the plan are adjusted in time to avoid grid operation errors; specifically, the operator formulates and evaluates the load shedding plan based on the real-time data of the incremental distribution network, and evaluates the feasibility and risks of the plan through simulation operations to avoid grid operation errors; by putting the rehearsed low-frequency and low-voltage load shedding plan for the distribution network load into use, the operating load of the incremental distribution network can be effectively reduced, so that the generators and other equipment in the incremental distribution network no longer operate under overload, thereby protecting the normal operation of the power generation equipment; when the frequency returns to normal, the device automatically releases the low-frequency load shedding operation to restore the normal operation of the power system.

[0070] The total load of each level of incremental distribution network is calculated through the real-time data of incremental distribution network load uploaded by each intelligent distribution terminal, and the low-frequency and low-voltage load reduction scheme of the incremental distribution network load entered is judged and selected according to the current total load of the incremental distribution network, and a standard low-frequency and low-voltage automatic load shedding scheme report is generated, and the automatic load shedding function in the low-frequency and low-voltage load shedding system is controlled to control a part of the load equipment in the incremental distribution network to switch on or off, so as to realize the low-frequency load shedding operation of the incremental distribution network load; specifically, by generating a standard low-frequency and low-voltage automatic load shedding scheme report, complex power grid data can be converted into an intuitive report form, which is convenient for operators to analyze and make decisions, avoid power grid misoperation, reduce the workload of automation maintenance, and ensure the stable operation of the power system.

[0071] For example, in this embodiment, when it is detected that the load frequency of the incremental distribution network is lower than the set threshold, the load reduction link will automatically start, and a part of the secondary loads in the incremental distribution network load, such as the lowest load in the commercial load, will be cut off to reduce the active power shortage of the incremental distribution network load, so that the operating frequency of the incremental distribution network load is stabilized within the normal range. It should be noted that the selection of load removal is based on their importance to the incremental distribution network load and the degree of influence on the entire power grid system; the load removed can be a secondary load or a non-critical load. At the same time, in order to ensure the accuracy and effectiveness of the load reduction measures, the low-frequency and low-voltage load reduction system will set a certain delay to distinguish other faults that may cause frequency fluctuations; the delay is usually between 0.2 and 0.5 seconds to ensure the accurate implementation of the measures; after the basic load reduction measures are implemented, if the incremental distribution network load frequency has not yet returned to the normal range, the backup load reduction measures will be triggered to further cut off part of the load to ensure the stability of the incremental distribution network load frequency; after taking the load reduction measures, the low-frequency and low-voltage load reduction system will take measures to gradually restore the removed loads, and monitor the incremental distribution network load frequency at the same time to ensure that it is restored to the allowed operating level.

[0072] S4. Establish an accident power restriction and new energy grid connection safety and stability control system, formulate a load control plan through the accident power restriction subsystem, ensure that power restriction measures are taken when implementing the incremental distribution network load control, and minimize the impact on users; also through the mutual cooperation of the stabilization control main station, stabilization substation and terminal station in the new energy grid connection safety and stability control subsystem, the energy storage, photovoltaic power station and the controllable load of each substation are included in the control main station to achieve load flexibility and precise control; Among them, the stabilization control main station in the new energy grid connection safety and stability control subsystem is located in the hub substation or power plant, which is responsible for aggregating information, forming control strategies and sending control commands; the stabilization substation is located in an important substation or power plant, which is responsible for collecting information and sending it to the main station, and the terminal station executes the control command and gives feedback; Specifically, the accident power restriction and new energy grid connection safety and stability control system is composed of the accident power restriction subsystem and the new energy grid connection safety and stability control subsystem. In the power system, when an accident or emergency occurs, in order to ensure the frequency and voltage of the incremental distribution network For example, when the incremental distribution network loses effective power supply, in order to maintain the frequency stability of the incremental distribution network, the low-frequency load reduction action can cut off the loads in the industrial load, commercial load, and residential load area with fewer electrical equipment and sparse population, aiming to avoid the collapse of the incremental distribution network and protect the stable operation of the power system; New energy grid connection safety and stability control subsystem: The system is mainly composed of the main station, substation and terminal station. The main station is usually located in the hub substation or in the power plant at the same location as the hub substation. It is responsible for summarizing the operating condition information of each substation, estimating the state of the regional power grid, identifying the operating mode of the regional power grid, and forming a safe and stable control strategy table online; the substation is installed in a more important substation or a power plant associated with the substation, responsible for collecting the operating condition information of the substation and transmitting it to the main station; the terminal station receives the control commands from each station, performs local control, and transmits the control result information to the upper station; through real-time monitoring and rapid response, the stability and safety of new energy grid connection are ensured.

[0073] S5. Establish a photovoltaic, storage and load coordination control system, conduct an early assessment of the operational risks of the power grid after energy storage is connected, conduct optimization analysis of the safety and stability control strategy after energy storage is connected, and conduct an economic evaluation of commercial operation; analyze the coordination scheme of new energy with energy storage and regional loads at different time periods under different output modes, propose the optimal source-grid-load-storage control strategy, and realize photovoltaic, storage and load flexible control; Among them, establishing a photovoltaic, storage and load coordination control system specifically includes the following steps:

[0074] Construct an energy storage control model and a new energy access model, import the energy storage, photovoltaic power station and controllable load information of each substation included in the control main station into the energy storage control model and the new energy access model for drills, analyze the transient safety and stability characteristics of the power grid, assess the operation risks of the power grid after energy storage access in advance, and optimize the power grid safety and stability control strategy according to the analysis results; Specifically, adjust and use the connected energy storage by following the following steps; Functional pre-control: During the period of minimum photovoltaic output every day, consider the predicted photovoltaic output and load plan for the next day, and charge and discharge the energy storage within the limit allowable range of the Nachaohe main transformer and the 110kV Shensu 7WA line, and preset it to the charging or discharging state that meets the maximum needs of the next day, so that it can meet the load demand and the maximum absorption demand of new energy; ② Real-time control: When the main transformer or line is overloaded, or the photovoltaic power generation exceeds expectations, real-time control is taken for energy storage and new energy to ensure equipment safety and maximize the absorption of new energy.

[0075] S6. Establish an information interaction platform, and use the wireless transmission network as the transmission medium to enable data interaction between the incremental distribution network load management system, intelligent distribution terminals, low-frequency and low-voltage load reduction system, and emergency power restriction and new energy grid connection safety and stability control systems. Ensure that data interfaces are developed between the systems to achieve linkage and optimize the incremental distribution network load control strategy.

[0076] Specifically, through the above analysis work, we will conduct an analysis of the safety and stability characteristics of the grid voltage, frequency, and power angle after the access of energy storage, and conduct an early assessment of the operating risks of the grid after the access of energy storage; conduct an optimization analysis of the safety and stability control strategy after the access of energy storage, and an economic evaluation of commercial operation; analyze the coordination of new energy with energy storage and loads in different periods of time under different output modes, and propose the optimal source-grid-load-storage control strategy to lay the foundation for the green and low-carbon operation of the region; finally, build a photovoltaic-storage-load coordinated control system to achieve flexible control of photovoltaic-storage-load.

[0077] The beneficial effects achieved by the above scheme are as follows: through the above operations, the incremental distribution network load management system, low-frequency and low-voltage load reduction system, accident power restriction and new energy grid-connected safety and stability control system cooperate with each other, utilize the existing system to optimize the configuration, develop data interfaces between the systems to achieve linkage, optimize the control strategy, and incorporate the controllable loads of energy storage, photovoltaic power stations and substations into the control master station to achieve flexible and precise load control.

[0078] Working principle: By comparing the incremental distribution network load with the low-voltage load reduction threshold, combined with the priority of each intelligent distribution terminal, the load is reduced by low voltage. This helps the distribution network to automatically reduce the load when the frequency or voltage is abnormal, ensuring the stable operation of the incremental distribution network; formulate a load control plan to ensure that power-limiting measures are taken when implementing the incremental distribution network load control to minimize the impact on users; and conduct an early assessment of the operating risks of the power grid after the energy storage is connected, analyze the coordination of new energy with energy storage and regional loads at different time periods under different output modes, and propose the optimal source-grid-load-storage control strategy to achieve flexible control of photovoltaic storage and load.

[0079] Furthermore, the comprehensive scores of all branch loads of the intelligent distribution terminal are calculated, including:

[0080] Obtain the load change curve of each branch load of the intelligent power distribution terminal, and determine the peak power consumption period parameters and valley power consumption period parameters of each branch load according to the load change curve;

[0081] Respectively obtain multiple power consumption indicators of each branch load under power consumption peak time period parameters and power consumption valley time period parameters;

[0082] Determine the electricity user based on the electricity consumption index, determine the load source characteristics based on the electricity user, and determine the strong correlation characteristics of each branch load based on the load source characteristics;

[0083] Acquire the modification attribute of the strongly correlated feature, and determine the modification subject of the modification attribute, wherein the modification subject includes: natural and artificial;

[0084] Determine the peak-cutting potential value or valley-flattening potential value of the strongly correlated feature according to the modified subject;

[0085] Determine the load variation range of each branch load according to the peak shaving potential value or the valley leveling potential value, and determine the load regulation score of each branch load according to the load variation range;

[0086] The effective static response load and the effective dynamic response load of each branch load are extracted respectively, and the demand response settlement score of each branch load is determined according to the effective static response load and the effective dynamic response load;

[0087] Determining a load supply score for each branch load based on the demand response settlement score;

[0088] Obtaining the grid topology structure of each branch load, determining the load loss factor according to the grid topology structure, and determining the load loss ratio of each branch load according to the load loss factor, grid data, and a preset grid utilization efficiency evaluation index;

[0089] The load loss score of each branch load is determined according to the load loss ratio, and the comprehensive score of all branch loads of the intelligent distribution terminal is calculated according to the load loss score, load supply score and load regulation score and their respective preset weights.

[0090] The beneficial effect of the above technical solution is: by determining the multi-dimensional load score of each branch load and then calculating the comprehensive score, a comprehensive score evaluation can be performed through multiple parameters such as load usage, loss, regulation, etc. of each branch load to ensure a comprehensive evaluation of each branch load.

[0091] Furthermore, before obtaining the priority of each intelligent power distribution terminal according to the ranking of the scores, the following steps are also included:

[0092] Obtain the changes in the operating parameters of each intelligent distribution terminal when the branch load is working, and construct the operating disturbance linearization matrix of each intelligent distribution terminal according to the changes in the operating parameters;

[0093] Obtain the minimum characteristic root of each intelligent distribution terminal under the current working condition according to the working condition disturbance linearization matrix;

[0094] The minimum characteristic root of each intelligent power distribution terminal under standard working conditions is obtained, and the working condition stability maintenance coefficient of each intelligent power distribution terminal is calculated according to the minimum characteristic root of each intelligent power distribution terminal under current working conditions and the minimum characteristic root under standard working conditions:

[0095]

[0096] Among them, S i is represented by the operating stability maintenance coefficient of the i-th intelligent distribution terminal, μ is represented by the linear load limit hyperparameter, and D 1i It is represented as the minimum characteristic root of the i-th intelligent distribution terminal under the current working condition, D 2i It is expressed as the minimum characteristic root of the i-th intelligent distribution terminal under standard working conditions, A i It is expressed as the maintenance coefficient of the i-th intelligent distribution terminal, α is the influence factor of the operating stability margin of the intelligent distribution terminal on the fluctuation degree of the load state variable, F i represents the number of branch loads of the i-th intelligent distribution terminal, j represents the j-th branch load, Q 1j Expressed as the maximum load of the j-th branch load, Q 2j It is expressed as the minimum load of the i-th branch load;

[0097] The priority evaluation weight of the working condition stability maintenance coefficient of the intelligent power distribution terminal and the priority evaluation weight of the comprehensive score of the branch load of each intelligent power distribution terminal are respectively set;

[0098] All intelligent distribution terminals are prioritized based on the set weights, the operating stability maintenance coefficient of each intelligent distribution terminal, and the score ranking.

[0099] The beneficial effects of the above technical solution are: by calculating the working condition stability maintenance coefficient of each intelligent power distribution terminal and then comprehensively prioritizing the intelligent power distribution terminals, the priority of the intelligent power distribution terminals can be evaluated in multiple dimensions based on the comprehensive scores of the working condition performance of the intelligent power distribution terminals and the branch load, thereby ensuring the objectivity and reliability of the evaluation results and improving practicality.

[0100] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0101] While the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and alterations may be made to the embodiments without departing from the principles and spirit of the invention.

Claims

1. A method for accurate control of incremental distribution network load, characterized in that: The following steps are involved: S1. Establish an incremental distribution network load management system, obtain and analyze the incremental distribution network load information in real time based on the intelligent distribution terminal, including the change trend, peak value and valley value of the incremental distribution network load, and accurately predict the incremental distribution network load change; S2. Establish the priority of each smart distribution terminal, calculate the comprehensive score of all branch loads of the smart distribution terminal according to the total amount of incremental distribution network loads of each level uploaded by the smart distribution terminal, and obtain the priority of each smart distribution terminal according to the score ranking; S3. Establish a low-frequency and low-voltage load reduction system. Based on the total load of each level of incremental distribution network uploaded by the intelligent distribution terminal and the priority of each intelligent distribution terminal, pre-build, enter and adjust the low-frequency and low-voltage load reduction plan of the incremental distribution network load to achieve low-frequency load reduction operation on the incremental distribution network load; S4. Establish an accident power restriction and new energy grid connection safety and stability control system, formulate a load control plan through the accident power restriction subsystem, ensure that power restriction measures are taken when implementing incremental distribution network load control, and minimize the impact on users; also through the mutual cooperation of the stabilization control master station, stabilization substation and terminal station in the new energy grid connection safety and stability control subsystem, the controllable loads of energy storage, photovoltaic power stations and substations are included in the control master station to achieve flexible and precise load control; S5. Establish a coordinated control system for photovoltaic, storage and load, conduct an early assessment of the operational risks of the power grid after the access of energy storage, and carry out optimization analysis of the safety and stability control strategy after the access of energy storage, as well as an economic assessment of commercial operation; analyze the coordination of new energy with energy storage and regional loads at different time periods under different output modes, propose the optimal source-grid-load-storage control strategy, and realize flexible control of photovoltaic, storage and load.

2. The incremental distribution network load precise control method according to claim 1 is characterized by: The following steps are also included: S6. Establish an information interaction platform, and use the wireless transmission network as the transmission medium to enable data interaction between the incremental distribution network load management system, intelligent distribution terminals, low-frequency and low-voltage load reduction system, and emergency power restriction and new energy grid connection safety and stability control systems. Ensure that data interfaces are developed between the systems to achieve linkage and optimize the incremental distribution network load control strategy.

3. The incremental distribution network load precise control method according to claim 1 is characterized by: After the incremental distribution network load management system is established in S1, the following steps are included: Collect multiple sets of historical incremental distribution network load information, clean and normalize the historical incremental distribution network load information; use the multiple sets of historical incremental distribution network load information as sample sets, and divide them into multiple sets of training sets and test sets; Construct an incremental distribution network load forecasting model, import the training set into the incremental distribution network load forecasting model for training, and output the training results; then import the test set into the incremental distribution network load forecasting model for testing, and output the test results; compare the two results to ensure that the test results are consistent with the training results; then optimize and iterate the incremental distribution network load forecasting model according to different groups of training sets and test sets to ensure the accuracy of the incremental distribution network load forecasting model early warning.

4. The incremental distribution network load precise control method according to claim 3 is characterized by: After the incremental distribution network load information is acquired and analyzed in real time according to the intelligent distribution terminal in S1, the following steps are included: The incremental distribution network load information is cleaned and normalized, the preprocessed incremental distribution network load information is imported into the incremental distribution network load early warning model for prediction, and then the current incremental distribution network load prediction result is output, and the current incremental distribution network load prediction result is uploaded to the information interaction platform for data interaction based on the wireless transmission network.

5. The incremental distribution network load precise control method according to claim 1 is characterized by: The calculation of the comprehensive scores of all branch loads of the intelligent distribution terminal in S2 specifically includes the following steps: Classify the loads in the incremental distribution network and divide them into primary loads, secondary loads, tertiary loads or industrial loads, commercial loads, and residential loads according to the importance of the loads or the power consumption characteristics of the loads; Based on the total amount of incremental distribution network load at each level uploaded by each smart distribution terminal, load calculation is performed according to the total capacity of the smart distribution terminal, the operating conditions of the smart distribution terminal and the power supply capacity of the power grid, and the load information of each smart distribution terminal is obtained. Combined with the load category of each smart distribution terminal, the priority of each smart distribution terminal is established.

6. The incremental distribution network load precise control method according to claim 1 is characterized by: The S3 pre-constructs, enters and adjusts the incremental distribution network load low-frequency and low-voltage load reduction plan, which specifically includes the following steps: According to the total load of each level of incremental distribution network uploaded by the smart distribution terminal, a low-frequency and low-voltage load reduction threshold is preset to determine whether the load information of the incremental distribution network exceeds the threshold range. If it does not exceed the threshold range, no low-frequency load reduction operation is performed; if it exceeds the threshold range, combined with the priority of each smart distribution terminal, it is determined to cut off the load of the smart distribution terminal of a certain load category, and based on this, a low-frequency and low-voltage load reduction plan for the incremental distribution network is formulated to restore the frequency balance of the incremental distribution network; among them, the low-frequency and low-voltage load reduction plan for the incremental distribution network includes at least three or more.

7. The incremental distribution network load precise control method according to claim 6 is characterized by: The S3 pre-constructs, records and adjusts the incremental distribution network load low-frequency and low-voltage load reduction plan, and also includes the following steps: After the low-frequency and low-voltage load shedding plan for the incremental distribution network load is formulated, the low-frequency and low-voltage load shedding plan for the incremental distribution network load is entered into the low-frequency and low-voltage load shedding system through the human-machine module in the low-frequency and low-voltage load shedding system, and the low-frequency and low-voltage load shedding plan for the incremental distribution network load is rehearsed. According to the rehearsal results, the shortcomings of the plan are adjusted in time to avoid grid operation errors; After the low-frequency and low-voltage load reduction plan for the incremental distribution network load is pre-built, entered and adjusted in S3, the following steps are included: The total load of each level of incremental distribution network is calculated through the real-time data of incremental distribution network load uploaded by each intelligent distribution terminal. The low-frequency and low-voltage load reduction scheme of the entered incremental distribution network load is judged and selected according to the current total load of the incremental distribution network, and a standard low-frequency and low-voltage automatic load shedding scheme report is generated. The automatic load shedding function in the low-frequency and low-voltage load shedding system is controlled to control the switching or closing of part of the load equipment in the incremental distribution network, so as to realize the low-frequency load shedding operation of the incremental distribution network load.

8. The incremental distribution network load precise control method according to claim 1 is characterized by: In the S4 new energy grid connection safety and stability control subsystem, the stability control master station is located in the hub substation or power plant, responsible for aggregating information, forming control strategies and sending control commands; the stability control substation is located in the important substation or power plant, responsible for collecting information and sending it to the master station; the terminal station executes the control command and provides feedback, ensuring the stability and safety of new energy power generation when connected to the grid through real-time monitoring and control; The light-storage-load coordination control system is established in S5, which specifically includes the following steps: Construct an energy storage control model and a new energy access model, import the energy storage, photovoltaic power station and controllable load information of each substation included in the control master station into the energy storage control model and the new energy access model for drills, analyze the transient safety and stability characteristics of the power grid, assess the operating risks of the power grid after energy storage access in advance, and optimize the power grid safety and stability control strategy based on the analysis results.

9. The incremental distribution network load precise control method according to claim 1, characterized in that: Calculate the comprehensive score of all branch loads of the intelligent distribution terminal, including: Obtain the load change curve of each branch load of the intelligent power distribution terminal, and determine the peak power consumption period parameters and valley power consumption period parameters of each branch load according to the load change curve; Respectively obtain multiple power consumption indicators of each branch load under power consumption peak time period parameters and power consumption valley time period parameters; Determine the electricity user based on the electricity consumption index, determine the load source characteristics based on the electricity user, and determine the strong correlation characteristics of each branch load based on the load source characteristics; Acquire the modification attribute of the strongly correlated feature, and determine the modification subject of the modification attribute, wherein the modification subject includes: natural and artificial; Determine the peak-cutting potential value or valley-flattening potential value of the strongly correlated feature according to the modified subject; Determine the load variation range of each branch load according to the peak shaving potential value or the valley leveling potential value, and determine the load regulation score of each branch load according to the load variation range; The effective static response load and the effective dynamic response load of each branch load are extracted respectively, and the demand response settlement score of each branch load is determined according to the effective static response load and the effective dynamic response load; Determining a load supply score for each branch load based on the demand response settlement score; Obtaining the grid topology structure of each branch load, determining the load loss factor according to the grid topology structure, and determining the load loss ratio of each branch load according to the load loss factor, grid data, and a preset grid utilization efficiency evaluation index; The load loss score of each branch load is determined according to the load loss ratio, and the comprehensive score of all branch loads of the intelligent distribution terminal is calculated according to the load loss score, load supply score and load regulation score and their respective preset weights.

10. The incremental distribution network load precise control method according to claim 2, characterized in that: Before obtaining the priority of each intelligent power distribution terminal according to the score sorting, it also includes: Obtain the changes in the operating parameters of each intelligent distribution terminal when the branch load is working, and construct the operating disturbance linearization matrix of each intelligent distribution terminal according to the changes in the operating parameters; Obtain the minimum characteristic root of each intelligent distribution terminal under the current working condition according to the working condition disturbance linearization matrix; The minimum characteristic root of each intelligent power distribution terminal under standard working conditions is obtained, and the working condition stability maintenance coefficient of each intelligent power distribution terminal is calculated according to the minimum characteristic root of each intelligent power distribution terminal under current working conditions and the minimum characteristic root under standard working conditions: Among them, S i is represented by the operating stability maintenance coefficient of the i-th intelligent distribution terminal, μ is represented by the linear load limit hyperparameter, and D 1i It is represented as the minimum characteristic root of the i-th intelligent distribution terminal under the current working condition, D 2i It is expressed as the minimum characteristic root of the i-th intelligent distribution terminal under standard working conditions, A i It is expressed as the maintenance coefficient of the i-th intelligent distribution terminal, α is the influence factor of the operating stability margin of the intelligent distribution terminal on the fluctuation of the load state variable, F i represents the number of branch loads of the i-th intelligent distribution terminal, j represents the j-th branch load, Q 1j Expressed as the maximum load of the j-th branch load, Q 2j It is expressed as the minimum load of the i-th branch load; The priority evaluation weight of the working condition stability maintenance coefficient of the intelligent power distribution terminal and the priority evaluation weight of the comprehensive score of the branch load of each intelligent power distribution terminal are respectively set; All intelligent distribution terminals are prioritized based on the set weights, the operating stability maintenance coefficient of each intelligent distribution terminal, and the score ranking.

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