Method and system for evaluating load carrying capacity of power distribution network for accommodating electric vehicle charging load

Abstract

The application relates to a power distribution network receiving electric vehicle charging load carrying capacity evaluation method and system, which comprises the following steps: acquiring basic parameters of the power distribution network, dividing the power distribution network according to the time and space characteristics of the electric vehicle load, and acquiring the total regular load curve of the power distribution network system according to the typical load curve of different functional areas; setting system operation limit conditions, configuring and setting the overcurrent protection according to the total regular load curve of the system, and obtaining the maximum load current flowing through the protection under different limit conditions; determining the limit condition of limiting the electric vehicle access scale according to the load current value flowing through the protection under each limit condition, and obtaining the evaluation result of the maximum accessible scale of the electric vehicle according to the limit condition and the evaluation benchmark. The application can eliminate the adverse effects of the electric vehicle charging load on the power distribution network and can be applied in the field of power distribution network planning.

Description

Technical Field

[0001] This invention relates to the field of power distribution network planning, and in particular to a method and system for assessing the load-carrying capacity of a power distribution network to accommodate electric vehicle charging loads. Background Technology

[0002] Currently, electric vehicles are primarily connected to the grid as charging loads. Their use as energy storage for grid discharge is still in the pilot project stage and has limited practical application. The large-scale integration of electric vehicles will pose significant challenges to the power grid, particularly in terms of load, operation and maintenance, and planning. Due to the highly random spatiotemporal distribution of electric vehicles, as the number of electric vehicles increases, disorderly charging can lead to a substantial increase in load, easily resulting in peak-load spikes, which significantly impacts the safe and reliable operation of the distribution network. Therefore, how to reasonably assess the distribution network's capacity to handle electric vehicle charging loads has become a pressing technical problem that needs to be solved. Summary of the Invention

[0003] To address the aforementioned problems, the purpose of this invention is to provide a method and system for assessing the load-carrying capacity of a power distribution network to accommodate electric vehicle charging loads, which can eliminate the adverse effects of electric vehicle charging loads on the power distribution network.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: a method for assessing the load-carrying capacity of a distribution network for electric vehicle charging, comprising: acquiring basic parameters of the distribution network; dividing the distribution network into functional zones according to the spatiotemporal characteristics of electric vehicle load; and obtaining the total conventional load curve of the distribution network system based on the typical load curves of different functional zones; setting system operating constraints; configuring and setting overcurrent protection based on the total conventional load curve of the system to obtain the maximum load current flowing through the protection under different constraints; determining the constraints limiting the scale of electric vehicle access based on the load current values ​​flowing through the protection under each constraint; and obtaining the assessment result of the maximum accessible scale of electric vehicles based on the constraints and assessment criteria.

[0005] Furthermore, the configuration and setting of the overcurrent protection includes:

[0006] The initial scale of electric vehicles is set according to the capacity and voltage level of the power distribution network;

[0007] Simulate the electric vehicle charging load by allocating the electric vehicle charging load of each functional area to each charging node according to the conventional load ratio, and then superimpose it with the conventional load to obtain the total load.

[0008] The system determines whether the total load meets the requirements based on the system's operating constraints. If it does, the maximum load current flowing through the protection is obtained.

[0009] Furthermore, the system operating constraints include: system rated capacity, node voltage deviation, and overcurrent protection sensitivity. This invention employs three constraints, particularly increasing overcurrent protection sensitivity, to more comprehensively reflect the distribution network's capacity to accommodate electric vehicle charging loads.

[0010] Furthermore, determining whether the total load meets the demand includes:

[0011] Determine if the system load is overloaded. If "yes", obtain the maximum load current flowing through the protection; if "no", determine the voltage deviation at the end node of the system.

[0012] Determine whether the voltage deviation at the end node of the system meets the requirements. If "yes", obtain the maximum load current flowing through the protection; otherwise, perform an overcurrent protection sensitivity assessment.

[0013] Determine whether the overcurrent protection sensitivity meets the requirements. If "yes", reset the initial electric vehicle scale. If "no", obtain the maximum load current flowing through the protection.

[0014] Furthermore, the maximum load current flowing through the protection under the two limiting conditions of the system's rated capacity and node voltage deviation is obtained through power flow calculation; the maximum load current flowing through the protection under the overcurrent protection sensitivity limiting condition is directly obtained based on the sensitivity requirements.

[0015] Furthermore, determining the scale of electric vehicle access includes:

[0016] By comparing the magnitude of the current flowing through the protected load under various limiting conditions, and by using the overcurrent value of the protection device itself and the difference between the current before the electric vehicles were connected, the power that can still be connected can be calculated, and the scale of electric vehicle connection can be determined.

[0017] Furthermore, the acquisition of the evaluation results includes:

[0018] The evaluation benchmark is the power flow at various time periods under normal load. The evaluation benchmark is compared with the power flow distribution after the electric vehicle charging load is connected, and the difference in power flow through each line is compared. The final evaluation result is obtained by using three limiting conditions: system rated capacity, node voltage deviation and overcurrent protection sensitivity.

[0019] A power distribution network load carrying capacity assessment system for electric vehicle charging includes: a first processing module for acquiring basic parameters of the power distribution network, dividing the power distribution network into functional zones according to the spatiotemporal characteristics of electric vehicle load, and obtaining the total conventional load curve of the power distribution network system based on typical load curves of different functional zones; a second processing module for setting system operating constraints, configuring and setting overcurrent protection based on the total conventional load curve of the system, and obtaining the maximum load current flowing through the protection under different constraints; and an assessment result output module for determining the constraints on the scale of electric vehicle access based on the load current values ​​flowing through the protection under each constraint, and obtaining the assessment result of the maximum scale of electric vehicles that can be accessed based on the constraints and assessment criteria.

[0020] A computer-readable storage medium storing one or more programs, the one or more programs including instructions that, when executed by a computing device, cause the computing device to perform any of the methods described above.

[0021] A computing device includes: one or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, and the one or more programs include instructions for performing any of the methods described above. Attached Figure Description

[0022] Figure 1 This is a flowchart of a method for assessing the load-bearing capacity of a power distribution network to accommodate electric vehicle charging loads, according to one embodiment of the present invention.

[0023] Figure 2 This is an improved IEEE-33 node distribution network topology diagram in one embodiment of the present invention;

[0024] Figure 3 This is a typical daily load variation curve for different functional areas in one embodiment of the present invention;

[0025] Figure 4a This is a conventional load curve under Example 1 in one embodiment of the present invention;

[0026] Figure 4b This is a conventional load curve under Example 2 in one embodiment of the present invention;

[0027] Figure 4c This is a conventional load curve under Example 3 in one embodiment of the present invention;

[0028] Figure 4d This is a conventional load curve under Example 4 in one embodiment of the present invention. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention are within the scope of protection of the present invention.

[0030] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0031] Since large-scale electric vehicle (EV) charging loads can adversely affect distribution network protection, this invention, based on the system rated capacity and node voltage deviation as limiting conditions for EV charging load acceptance, adds overcurrent protection sensitivity as a limiting condition. Using these three conditions as constraints, the invention analyzes the distribution network's capacity to accept EV charging loads. The invention includes: obtaining basic distribution network parameters to determine evaluation criteria; dividing the distribution network into functional zones according to the spatiotemporal characteristics of EV loads; obtaining the overall conventional load curve of the distribution network system based on typical load curves of different functional zones; setting system operating constraints; configuring and setting overcurrent protection based on the overall conventional load curve of the system to obtain the maximum load current flowing through the protection under different constraints; determining the main limiting factors restricting the scale of EV access based on the load current values ​​flowing through the protection under each constraint; and obtaining the evaluation result of the maximum acceptable scale of EV access based on the main limiting factors and evaluation criteria. This invention can eliminate the adverse effects of EV charging loads on the distribution network.

[0032] In one embodiment of the present invention, a method for assessing the load-carrying capacity of a power distribution network for electric vehicle charging is provided. In this embodiment, as shown... Figure 1 As shown, the method includes the following steps:

[0033] 1) Obtain the basic parameters of the distribution network, divide the distribution network into functional zones according to the spatiotemporal characteristics of electric vehicle load, and obtain the total conventional load curve of the distribution network system based on the typical load curves of different functional zones;

[0034] 2) Set system operating limits and configure and set the overcurrent protection according to the system's total conventional load curve to obtain the maximum load current flowing through the protection under different limiting conditions.

[0035] 3) Based on the load current values ​​flowing through the protection under each limiting condition, determine the limiting conditions for the scale of electric vehicles connected to the network, and obtain the evaluation results of the maximum scale of electric vehicles that can be connected to the network based on the limiting conditions and evaluation criteria.

[0036] In step 1) above, the basic parameters of the distribution network include: rated voltage, rated capacity, network topology, node conventional load, line parameters, etc. These basic parameters are used as the evaluation benchmark.

[0037] Step 2) above involves configuring and setting the overcurrent protection, including the following steps:

[0038] 2.1) Initialize the electric vehicle scale according to the capacity and voltage level of the distribution network, that is, the number of electric vehicles connected in different functional areas of the distribution network;

[0039] 2.2) Simulate electric vehicle charging load, distribute the electric vehicle charging load of each functional area to each charging node according to the conventional load ratio, and superimpose it with the conventional load to obtain the total load;

[0040] In this embodiment, the Monte Carlo random sampling method is used to simulate the charging load of electric vehicles.

[0041] 2.3) Determine whether the total load meets the requirements based on the system operating constraints. If it does, obtain the maximum load current flowing through the protection.

[0042] The system operating limitations include: system rated capacity, node voltage deviation, and overcurrent protection sensitivity.

[0043] In step 2.3) above, determining whether the total load meets the demand includes the following steps:

[0044] 2.3.1) Determine whether the system load is overloaded. If "yes", obtain the maximum load current flowing through the protection. If "no", determine the voltage deviation at the end node of the system.

[0045] 2.3.2) Determine whether the voltage deviation at the end node of the system meets the requirements. If "yes", obtain the maximum load current flowing through the protection; if "no", perform an overcurrent protection sensitivity judgment.

[0046] 2.3.3) Determine whether the overcurrent protection sensitivity meets the requirements. If “yes”, reset the initial electric vehicle scale. If “no”, obtain the maximum load current flowing through the protection.

[0047] In the above embodiments, the maximum load current flowing through the protection under the two limiting conditions of system rated capacity and node voltage deviation is obtained through power flow calculation; the maximum load current flowing through the protection under the overcurrent protection sensitivity limiting condition is directly obtained according to the sensitivity requirements.

[0048] In step 3) above, determining the scale of electric vehicle access is specifically as follows:

[0049] By comparing the magnitude of the current flowing through the protected load under various limiting conditions, and by using the overcurrent value of the protection device itself and the difference between the current before the electric vehicles were connected, the power that can still be connected can be calculated, and the scale of electric vehicle connection can be determined.

[0050] In step 3) above, obtaining the evaluation results includes:

[0051] The evaluation benchmark is the power flow at various time periods under normal load. The evaluation benchmark is compared with the power flow distribution after the electric vehicle charging load is connected. After the electric vehicles are fully connected, the difference in power flow through each line is compared. The final evaluation result is obtained by using three limiting conditions: system rated capacity, node voltage deviation and overcurrent protection sensitivity.

[0052] Implementation Example: This embodiment uses, for example... Figure 2 The improved IEEE-33 node distribution network shown was simulated and verified. The system base capacity was 10 MVA, the rated voltage at the power supply end was 12.66 kV, the total active load at each node was 3715 kW, the total reactive load was 2300 kVar, the system rated capacity was 5700 kVA, and the system impedances under the maximum and minimum operating modes were X and X, respectively. s,max =3.1Ω, X s,min =6.9Ω. The overcurrent protection configuration for this distribution network line is as follows: Figure 2 As shown, CB1, CB2, CB3, CB4, CB5, and CB6 are respectively, with a reliability coefficient of 100%. The self-starting coefficient of the motor is Kms = 1.3, and the return coefficient is Kre = 0.95. The near backup sensitivity coefficient is required to be greater than or equal to 1.3.

[0053] Based on the analysis of electric vehicle travel data from a certain city, it was found that electric vehicle travel activities mainly occur in residential areas, commercial areas, and work areas. Typical daily load variation curves for different functional areas are shown below. Figure 3 As shown.

[0054] To evaluate the maximum scale of electric vehicle access under different scenarios, this embodiment sets up four simulation cases, as follows:

[0055] Case 1: The distribution network area is a residential area. The corresponding nodes in the example are 2 to 33. Each node in this residential area is set as an electric vehicle charging node.

[0056] Case 2: The power distribution network area includes residential areas and working areas. The working areas correspond to nodes 2-6 and 19-25, while the residential areas correspond to nodes 7-18 and 26-33. All nodes in each functional area are set as electric vehicle charging nodes.

[0057] Case 3: The power distribution network area includes residential areas, work areas and commercial areas. The nodes corresponding to the residential areas are 9-18 and 26-33, the nodes corresponding to the commercial areas are 7-8 and 23-25, and the nodes corresponding to the work areas are 2-6 and 19-22. All nodes in each functional area are set as electric vehicle charging nodes.

[0058] Case 4: This power distribution network area includes residential areas, work areas, and commercial areas. The nodes corresponding to the residential areas are 2-6, 9-22, 26-28, and 33; the nodes corresponding to the commercial areas are 7-8 and 23-25; and the nodes corresponding to the work areas are 29-32. Nodes 4, 12, 19, 21, 27, and 28 in the residential areas are set as electric vehicle charging nodes; nodes 7 and 25 in the commercial areas are set as electric vehicle charging nodes; and nodes 29 and 32 in the work areas are set as electric vehicle charging nodes.

[0059] Simulation Result Analysis: Based on Figure 3 Typical daily load variation curves for each functional area are obtained by proportionally scaling the known load parameters of each node in the IEEE-33 node distribution network to obtain the 24-hour load variation curves for each node in the system. The loads of each node are then superimposed to obtain the conventional load curves for distribution networks in Cases 1 to 4, respectively. Figures 4a to 4d As shown.

[0060] Depend on Figures 4a to 4d It can be seen that in Case 1, peak residential electricity loads occurred at 11:00 AM and 7:00 PM, with the maximum load peak approaching the system's rated capacity. Cases 2 through 4 showed similar trends in the distribution network's conventional load curves: high load from 10:00 AM to 7:00 PM (peak load period), low load from 11:00 PM to 7:00 AM the following day, and the maximum load peak at 6:00 PM. The overcurrent protection settings and sensitivity verification for the IEEE-33 node distribution network were performed, and the results are shown in Table 1.

[0061] Table 1 Overcurrent Protection Setting and Sensitivity Verification

[0062]

[0063] Based on relevant calculations and analysis, the following conclusions can be drawn: Case 1, limited by the system's rated capacity at 19:00, has a maximum capacity of 800 electric private vehicles; Case 2, limited by the end node 18 at 18:00, has a maximum capacity of 1000 electric private vehicles; Case 3, limited by the system's rated capacity at 13:00, has a maximum capacity of 65 electric taxis; at 18:00, limited by the voltage of the end node 18, its maximum capacity of electric private vehicles is 1125; Case 4, limited by the sensitivity of protection CB1 at 13:00, has a maximum capacity of 70 electric taxis; at 18:00, limited by the system's capacity, its maximum capacity of electric private vehicles is 2500.

[0064] In Case 1 and Case 2, when the maximum number of electric private cars were connected, the load current flowing through protection CB3 exceeded its original setting. In Case 3, when the maximum number of electric taxis and private cars were connected, the load current flowing through protection CB3 and CB4 exceeded their original protection settings. In Case 4, when the maximum number of electric taxis and private cars were connected, the load current flowing through protection CB3, CB4, and CB6 exceeded their original protection settings. To prevent maloperation of the protections, the settings of protection CB3, CB4, and CB6 need to be increased. However, the sensitivity of each protection still meets the requirements after the settings are modified.

[0065] In one embodiment of the present invention, a system for assessing the load-carrying capacity of a power distribution network for electric vehicle charging is provided, comprising:

[0066] The first processing module acquires basic parameters of the distribution network, divides the distribution network into functional zones according to the spatiotemporal characteristics of electric vehicle load, and obtains the total conventional load curve of the distribution network system based on the typical load curves of different functional zones.

[0067] The second processing module sets system operating constraints and configures and sets the overcurrent protection based on the system's overall conventional load curve to obtain the maximum load current flowing through the protection under different constraints.

[0068] The evaluation result output module determines the limiting conditions for the scale of electric vehicles to be connected based on the load current value flowing through the protection under each limiting condition, and obtains the evaluation result of the maximum scale of electric vehicles that can be connected based on the limiting conditions and the evaluation benchmark.

[0069] The second processing module described above configures and sets the overcurrent protection, including:

[0070] Initialize the scale of electric vehicles based on the capacity and voltage level of the power distribution network;

[0071] Simulate the electric vehicle charging load by allocating the electric vehicle charging load of each functional area to each charging node according to the conventional load ratio, and then superimpose it with the conventional load to obtain the total load.

[0072] The system determines whether the total load meets the requirements based on the system's operating constraints. If it does, the maximum load current flowing through the protection is obtained.

[0073] The system operating limitations include: system rated capacity, node voltage deviation, and overcurrent protection sensitivity.

[0074] In the above embodiments, determining whether the total load meets the demand includes:

[0075] Determine if the system load is overloaded. If "yes", obtain the maximum load current flowing through the protection; if "no", determine the voltage deviation at the end node of the system.

[0076] Determine whether the voltage deviation at the end node of the system meets the requirements. If "yes", obtain the maximum load current flowing through the protection; otherwise, perform an overcurrent protection sensitivity assessment.

[0077] Determine whether the overcurrent protection sensitivity meets the requirements. If "yes", reset the initial electric vehicle scale. If "no", obtain the maximum load current flowing through the protection.

[0078] In the above embodiments, the maximum load current flowing through the protection under the two limiting conditions of system rated capacity and node voltage deviation is obtained through power flow calculation; the maximum load current flowing through the protection under the overcurrent protection sensitivity limiting condition is directly obtained according to the sensitivity requirements.

[0079] The determination of the scale of electric vehicle access in the above evaluation result output module is as follows:

[0080] By comparing the magnitude of the current flowing through the protected load under various limiting conditions, and by using the overcurrent value of the protection device itself and the difference between the current before the electric vehicles were connected, the power that can still be connected can be calculated, and the scale of electric vehicle connection can be determined.

[0081] The evaluation result output module described above includes the following steps for obtaining the evaluation results:

[0082] The evaluation benchmark is the power flow at various time periods under normal load. The evaluation benchmark is compared with the power flow distribution after the electric vehicle charging load is connected, and the difference in power flow through each line is compared. The final evaluation result is obtained by using three limiting conditions: system rated capacity, node voltage deviation and overcurrent protection sensitivity.

[0083] The system provided in this embodiment is used to execute the above-described method embodiments. For specific processes and details, please refer to the above embodiments, which will not be repeated here.

[0084] In one embodiment of the present invention, a computing device is provided, which can be a terminal and may include: a processor, a communication interface, memory, a display screen, and an input device. The processor, communication interface, and memory communicate with each other via a communication bus. The processor provides computing and control capabilities. The memory includes a non-volatile storage medium and internal memory. The non-volatile storage medium stores an operating system and a computer program. When the computer program is executed by the processor, it implements a method for assessing the load-bearing capacity of a power distribution network for accepting electric vehicle charging loads. The internal memory provides an environment for the operation of the operating system and computer program in the non-volatile storage medium. The communication interface is used for wired or wireless communication with external terminals. Wireless communication can be achieved through Wi-Fi, a management network, NFC (Near Field Communication), or other technologies. The display screen can be a liquid crystal display or an e-ink display. The input device can be a touch layer covering the display screen, or buttons, a trackball, or a touchpad mounted on the casing of the computing device, or an external keyboard, touchpad, or mouse, etc. The processor can call logic instructions in memory to execute the following methods: obtain basic parameters of the distribution network; divide the distribution network into functional zones according to the spatiotemporal characteristics of electric vehicle loads; obtain the total conventional load curve of the distribution network system based on the typical load curves of different functional zones; set system operating constraints; configure and set overcurrent protection based on the total conventional load curve of the system; obtain the maximum load current flowing through the protection under different constraints; determine the constraints on the scale of electric vehicle access based on the load current values ​​flowing through the protection under each constraint; and obtain the evaluation result of the maximum scale of electric vehicles that can be accessed based on the constraints and evaluation criteria.

[0085] Furthermore, the logical instructions in the aforementioned memory can be implemented as software functional units and sold or used as independent products, and can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0086] Those skilled in the art will understand that the structure of the above-described computing device is only a partial structure related to the solution of this application and does not constitute a limitation on the computing device to which the solution of this application is applied. A specific computing device may include more or fewer components, or combine certain components, or have different component arrangements.

[0087] In one embodiment of the present invention, a computer program product is provided, the computer program product including a computer program stored on a non-transitory computer-readable storage medium, the computer program including program instructions, when the program instructions are executed by a computer, the computer can execute the methods provided in the above-described method embodiments, such as: obtaining basic parameters of the distribution network, dividing the distribution network into functional zones according to the spatiotemporal characteristics of electric vehicle load, and obtaining the total conventional load curve of the distribution network system according to the typical load curves of different functional zones; setting system operation constraints, configuring and setting overcurrent protection according to the total conventional load curve of the system, and obtaining the maximum load current flowing through the protection under different constraints; determining the constraints limiting the scale of electric vehicle access according to the load current value flowing through the protection under each constraint, and obtaining the evaluation result of the maximum accessible scale of electric vehicles according to the constraints and evaluation criteria.

[0088] In one embodiment of the present invention, a non-transitory computer-readable storage medium is provided, which stores server instructions that cause a computer to execute the methods provided in the above embodiments, including, for example,: acquiring basic parameters of the distribution network; dividing the distribution network into functional zones according to the spatiotemporal characteristics of electric vehicle loads; and acquiring the total conventional load curve of the distribution network system based on typical load curves of different functional zones; setting system operating constraints; configuring and setting overcurrent protection based on the total conventional load curve of the system; obtaining the maximum load current flowing through the protection under different constraints; determining the constraints limiting the scale of electric vehicle access based on the load current values ​​flowing through the protection under each constraint; and obtaining the evaluation result of the maximum accessible scale of electric vehicles based on the constraints and evaluation criteria.

[0089] The computer-readable storage medium provided in the above embodiments has a similar implementation principle and technical effect to the above method embodiments, and will not be described again here.

[0090] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0091] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0092] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0093] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for assessing the load-carrying capacity of a power distribution network for electric vehicle charging, characterized in that, include: Obtain basic parameters of the distribution network, divide the distribution network into functional zones according to the spatiotemporal characteristics of electric vehicle load, and obtain the total conventional load curve of the distribution network system based on the typical load curves of different functional zones; The system sets operating constraints and configures and sets the overcurrent protection based on the system's total conventional load curve to obtain the maximum load current flowing through the protection under different constraints. The configuration and setting of the overcurrent protection includes: setting the initial electric vehicle scale according to the distribution network capacity and voltage level; simulating the electric vehicle charging load, distributing the electric vehicle charging load of each functional area to each charging node according to the conventional load ratio, and superimposing it with the conventional load to obtain the total load; determining whether the total load meets the requirements based on the system operating constraints, and if so, obtaining the maximum load current flowing through the protection. Based on the load current values ​​flowing through the protection under various limiting conditions, the limiting conditions for the scale of electric vehicles connected are determined, and the evaluation results of the maximum scale of electric vehicles that can be connected are obtained based on the limiting conditions and evaluation criteria. The determination of the scale of electric vehicle access includes: By comparing the magnitude of the current flowing through the protected load under various limiting conditions, and by using the overcurrent value of the protection device itself and the current difference before the electric vehicles were connected, the remaining power can be calculated, and the scale of electric vehicle connection can be determined. The determination of whether the total load meets the demand includes: Determine if the system load is overloaded. If "yes", obtain the maximum load current flowing through the protection. If "no", determine the voltage deviation at the end node of the system. Determine whether the voltage deviation at the end node of the system meets the requirements. If "yes", obtain the maximum load current flowing through the protection; if "no", perform an overcurrent protection sensitivity assessment. Determine whether the overcurrent protection sensitivity meets the requirements. If "yes", reset the initial electric vehicle scale. If "no", obtain the maximum load current flowing through the protection. The maximum load current flowing through the protection under the two limiting conditions of the system's rated capacity and node voltage deviation is obtained through power flow calculation; the maximum load current flowing through the protection under the overcurrent protection sensitivity limiting condition is directly obtained based on the sensitivity requirements.

2. The method for assessing the load-carrying capacity of a distribution network for electric vehicle charging as described in claim 1, characterized in that, The system operating limitations include: system rated capacity, node voltage deviation, and overcurrent protection sensitivity.

3. The method for assessing the load-carrying capacity of a distribution network for electric vehicle charging as described in claim 1, characterized in that, The acquisition of the evaluation results includes: The evaluation benchmark is the power flow at various time periods under normal load. The evaluation benchmark is compared with the power flow distribution after the electric vehicle charging load is connected, and the difference in power flow through each line is compared. The final evaluation result is obtained by using three limiting conditions: system rated capacity, node voltage deviation and overcurrent protection sensitivity.

4. A system for assessing the load-carrying capacity of a distribution network for electric vehicle charging, used to implement the method for assessing the load-carrying capacity of a distribution network for electric vehicle charging as described in any one of claims 1 to 3, characterized in that, include: The first processing module acquires basic parameters of the distribution network, divides the distribution network into functional zones according to the spatiotemporal characteristics of electric vehicle load, and obtains the total conventional load curve of the distribution network system based on the typical load curves of different functional zones. The second processing module sets system operating constraints and configures and sets the overcurrent protection based on the system's overall conventional load curve to obtain the maximum load current flowing through the protection under different constraints. The evaluation result output module determines the limiting conditions for the scale of electric vehicles to be connected based on the load current value flowing through the protection under each limiting condition, and obtains the evaluation result of the maximum scale of electric vehicles that can be connected based on the limiting conditions and the evaluation benchmark.

5. A computer-readable storage medium for storing one or more programs, characterized in that, The one or more programs include instructions that, when executed by a computing device, cause the computing device to perform any of the methods described in claims 1 to 3.

6. A computing device, characterized in that, include: One or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the one or more programs including instructions for performing any of the methods described in claims 1 to 3.

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