Method and device for determining number of low-voltage users and computer program product

Abstract

The invention provides a method and device for determining the number of low-voltage users and a computer program product. The method comprises the steps of obtaining a first user number at a first moment; acquiring a power supply radius difference value; determining a second user number at a second moment according to the power supply radius difference value; and calculating the sum of the first user number and the second user number to obtain the target user number. According to the scheme, the problems that the number of low-voltage users in a plurality of transformer areas in the area cannot be predicted and a reference basis cannot be provided for a power supply enterprise to predict the low-voltage condition in a single transformer area or a district in advance in the prior art are solved.

Description

Technical Field

[0001] The present application relates to the technical field of distribution network analysis, and in particular to a method, device, computer program product and system for determining the number of low-voltage users. Background Art

[0002] In recent years, with the development of the economy, the load of rural power grids has grown rapidly, and the electricity demand of users has continued to increase. However, the current rural power grid lines are dilapidated, the power supply distance is too long, and the wire diameter is too thin, resulting in insufficient terminal voltage, which seriously affects the normal electricity consumption of rural power grid users. Power supply companies monitor the voltage data of each user station area terminal and user smart meter through the system, statistically analyze the voltage fluctuations over a period of time, select the stations that meet the low voltage judgment standards, and then transform and upgrade these low-voltage stations through relevant operation and maintenance means or engineering projects, thereby solving the low voltage problem.

[0003] The existing method can quickly determine whether the voltage value of a certain node in the current low-voltage line network in the substation has reached low voltage (less than 198V is considered low voltage). In addition, this method can also be used to analyze and predict newly registered low-voltage users to determine whether low voltage will occur after they are connected.

[0004] However, this method cannot predict the number of low-voltage users in multiple substations in the region, and cannot provide a reference for power supply companies to predict low voltage conditions in a single substation or area in advance. Summary of the invention

[0005] The main purpose of the present application is to provide a method, device, computer program product and user quantity determination system for determining the number of low-voltage users, so as to at least solve the problem in the prior art that it is impossible to predict the number of low-voltage users in multiple substations in a region, and it is impossible to provide a reference basis for power supply companies to predict the low voltage situation in a single substation or area in advance.

[0006] In order to achieve the above-mentioned purpose, according to one aspect of the present application, a method for determining the number of low-voltage users is provided, including: obtaining the first number of users at a first moment, wherein the first number of users is the number of user nodes whose voltage value is less than or equal to a preset voltage value in the power supply area of ​​the transformer at the first moment; obtaining a power supply radius difference, wherein the power supply radius difference is the difference between the first maximum power supply radius of the transformer at the first moment and the second maximum power supply radius of the transformer at the second moment, and the first moment is earlier than the second moment; determining the second number of users at the second moment according to the power supply radius difference, wherein the second number of users is the number of newly added user nodes whose voltage value is less than or equal to the preset voltage value in the power supply area of ​​the transformer at the second moment, wherein the power supply radius difference is positively correlated with the second number of users; calculating the sum of the first number of users and the second number of users to obtain the target number of users.

[0007] Optionally, obtaining the power supply radius difference includes: obtaining a first current value, wherein the first current value is the phase current value of the transformer at the first moment; determining the first maximum power supply radius according to the first current value, wherein the first maximum power supply radius is a power supply radius that is greater than the preset voltage value and can be provided by the transformer at the first moment; determining a second current value according to the first current value, wherein the second current value is the phase current value of the transformer at the second moment; determining the second maximum power supply radius according to the second current value, wherein the second maximum power supply radius is a power supply radius that is greater than the preset voltage value and can be provided by the transformer at the second moment; and calculating the difference between the first maximum power supply radius and the second maximum power supply radius to obtain the power supply radius difference.

[0008] Optionally, obtaining the first current value includes: calculating the first current value according to a first formula, wherein the first formula is:

[0009]

[0010] I0 represents the first current value, R represents the resistance value of the transformer, η% represents the maximum load rate of the transformer at the first moment, and n represents the number of outgoing line loops of the transformer at the first moment.

[0011] Optionally, determining the first maximum power supply radius according to the first current value includes: calculating the first maximum power supply radius according to a second formula, wherein the second formula is:

[0012]

[0013] L0 represents the first maximum power supply radius, U0 represents the single-phase voltage value output by the transformer, S represents the cross-section of the conductor transmitted by the transformer, and ρ represents the resistivity of the conductor transmitted by the transformer.

[0014] Optionally, determining the second current value according to the first current value includes: calculating the second current value according to a third formula, wherein the third formula is:

[0015]

[0016] I X represents the second current value, α represents the natural growth rate of load, dp i represents the reported load of the user node of a single phase, β i The coefficient representing the reported load, Indicates the power factor of the reported load, sp i Represents the reported load of the user node of the three phases.

[0017] Optionally, determining the second maximum power supply radius according to the second current value includes: calculating the second maximum power supply radius according to a fourth formula, wherein the fourth formula is:

[0018]

[0019] L x Indicates the second maximum power supply radius.

[0020] Optionally, determining the number of second users at the second moment according to the power supply radius difference includes: calculating the number of second users according to a fifth formula, wherein the fifth formula is:

[0021]

[0022] D represents the number of the second users, W represents the number of the first users, and L M represents the current maximum power supply radius of the transformer, and ΔL represents the power supply radius difference.

[0023] According to another aspect of the present application, a device for determining the number of low-voltage users is provided, comprising: a first acquisition unit, used to acquire the first number of users at a first moment, wherein the first number of users is the number of user nodes whose voltage value is less than or equal to a preset voltage value in the power supply area of ​​the transformer at the first moment; a second acquisition unit, used to acquire a power supply radius difference, wherein the power supply radius difference is the difference between a first maximum power supply radius of the transformer at the first moment and a second maximum power supply radius of the transformer at the second moment, and the first moment is earlier than the second moment; a determination unit, used to determine the second number of users at the second moment according to the power supply radius difference, wherein the second number of users is the number of newly added user nodes whose voltage value is less than or equal to the preset voltage value in the power supply area of ​​the transformer at the second moment, and wherein the power supply radius difference is positively correlated with the second number of users; and a calculation unit, used to calculate the sum of the first number of users and the second number of users to obtain a target number of users.

[0024] According to another aspect of the present application, a computer program product is provided, comprising a computer program, wherein when the computer program is executed by a processor, the computer program implements the steps of any one of the methods for determining the number of low-voltage users.

[0025] According to another aspect of the present application, a system for determining the number of users is provided, comprising: one or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and are configured to be executed by the one or more processors, and the one or more programs include a method for determining the number of low-voltage users to execute any one of the above-described methods.

[0026] By applying the technical solution of the present application, the number of low-voltage users can be determined by the power supply range of the transformer. With the application of the power grid, more and more equipment is added to the power grid, which requires a large amount of voltage to supply power. As the number of equipment that needs to be powered increases, the maximum power supply radius of the transformer will also decrease. As the power supply radius decreases, the voltage value obtained by the user node at the end of the power supply will become smaller and smaller, making the user node at the end of the power supply become a low-voltage user node (less than 198V is a low-voltage user node). Therefore, this solution can determine the number of low-voltage users in a single substation or area by changing the power supply radius of the transformer, thereby solving the problem in the prior art that it is impossible to provide a reference basis for power supply companies to predict low voltage conditions in a single substation or area in advance. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The drawings constituting part of the present application are used to provide a further understanding of the present application. The exemplary embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0028] Figure 1 A hardware structure block diagram of a mobile terminal for performing a method for determining the number of low-voltage users provided in an embodiment of the present application is shown;

[0029] Figure 2 A schematic flow chart of a method for determining the number of low-voltage users provided in accordance with an embodiment of the present application is shown;

[0030] Figure 3 A schematic diagram showing the shrinkage of the power supply radius under normal voltage is shown;

[0031] Figure 4 A structural block diagram of a device for determining the number of low-voltage users provided according to an embodiment of the present application is shown.

[0032] The above drawings include the following reference numerals:

[0033] 102, processor; 104, memory; 106, transmission device; 108, input and output devices. DETAILED DESCRIPTION

[0034] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0035] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0036] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0037] In addition to system background monitoring, the voltage on the user side can also be judged and predicted through the line voltage loss table. As shown in Table 1, Table 1 shows the voltage drop of a single 70mm2 aluminum core overhead line. Given the wire diameter of the front-end conductor of the user node and the node load, and the distance of the node, the corresponding voltage drop value can be queried through the table. Assuming that the single-phase voltage at the output end of the transformer remains unchanged at 220V, the voltage value of the user node can be obtained, thereby determining whether there is low voltage.

[0038] Table 1

[0039]

[0040] As introduced in the background technology, the prior art is unable to predict the number of low-voltage users in multiple substations in a region, and is unable to provide a reference basis for power supply companies to predict the low voltage situation in a single substation or area in advance. To solve the above problems, the embodiments of the present application provide a method, device, computer program product and user quantity determination system for determining the number of low-voltage users.

[0041] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0042] The method embodiments provided in the embodiments of the present application can be executed in a mobile terminal, a computer terminal or a similar computing device. Taking running on a mobile terminal as an example, Figure 1 FIG. 1 is a hardware structure block diagram of a mobile terminal of a method for determining the number of low-voltage users according to an embodiment of the present invention. Figure 1 As shown, the mobile terminal may include one or more ( Figure 1Only one is shown in the figure) a processor 102 (the processor 102 may include but is not limited to a processing device such as a microprocessor MCU or a programmable logic device FPGA) and a memory 104 for storing data, wherein the mobile terminal may also include a transmission device 106 and an input / output device 108 for communication functions. It can be understood by those skilled in the art that Figure 1 The structure shown is only for illustration and does not limit the structure of the mobile terminal. Figure 1 More or fewer components as shown, or with Figure 1 Different configurations are shown.

[0043] The memory 104 can be used to store computer programs, for example, software programs and modules of application software, such as the computer program corresponding to the display method of device information in the embodiment of the present invention. The processor 102 executes various functional applications and data processing by running the computer program stored in the memory 104, that is, the above method is implemented. The memory 104 may include a high-speed random access memory, and may also include a non-volatile memory, such as one or more magnetic storage devices, flash memory, or other non-volatile solid-state memory. In some examples, the memory 104 may further include a memory remotely arranged relative to the processor 102, and these remote memories can be connected to the mobile terminal via a network. Examples of the above-mentioned network include but are not limited to the Internet, an intranet, a local area network, a mobile communication network, and a combination thereof. The transmission device 106 is used to receive or send data via a network. The above-mentioned specific examples of the network may include a wireless network provided by a communication provider of the mobile terminal. In one example, the transmission device 106 includes a network adapter (Network Interface Controller, referred to as NIC), which can be connected to other network devices through a base station so as to communicate with the Internet. In one example, the transmission device 106 may be a radio frequency (RF) module, which is used to communicate with the Internet wirelessly.

[0044] In this embodiment, a method for determining the number of low-voltage users running on a mobile terminal, a computer terminal or a similar computing device is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0045] Figure 2 FIG. 1 is a flow chart of a method for determining the number of low-voltage users according to an embodiment of the present application. Figure 2 As shown, the method comprises the following steps:

[0046] Step S201, obtaining the first number of users at a first moment, wherein the first number of users is the number of user nodes whose voltage value is less than or equal to a preset voltage value in a power supply area of ​​the transformer at the first moment;

[0047] Specifically, during the operation of the transformer at the current first moment, the transformer supplies power to the power supply area, which includes multiple user nodes. The user nodes can be powered. The user nodes are users who need power supply. They are the end of the power system, that is, the final destination of power transmission, usually connected to the user equipment or load. At this node, electrical energy is converted into other forms of energy for users to use, such as light energy, thermal energy, etc. However, some users are far away and the voltage value they get is low voltage. The preset voltage value is 198V. User nodes with a voltage less than 198V are all low voltage. Therefore, the number of first users at the current first moment can be obtained.

[0048] Step S202, obtaining a power supply radius difference, wherein the power supply radius difference is a difference between a first maximum power supply radius of the transformer at the first moment and a second maximum power supply radius of the transformer at the second moment, the first moment being earlier than the second moment;

[0049] Specifically, as the number of devices that need power supply increases, the maximum power supply radius of the transformer will also decrease. As the power supply radius decreases, the voltage value obtained by the user node at the end of the power supply will become smaller and smaller, making the user node at the end of the power supply become a low-voltage user node (less than 198V is a low-voltage user node).

[0050] Specifically, the first maximum power supply radius of the transformer at the first moment and the second maximum power supply radius of the transformer at the second moment can be obtained, and the difference between the two radii is calculated to obtain the reduced power supply area of ​​the transformer, that is, the power supply radius difference.

[0051] Step S203, determining the number of second users at the second moment according to the power supply radius difference, wherein the number of second users is the number of newly added user nodes whose voltage value is less than or equal to the preset voltage value in the power supply area of ​​the transformer at the second moment, wherein the power supply radius difference is positively correlated with the number of second users;

[0052] Specifically, as the voltage value obtained by the user node at the power supply end becomes smaller and smaller, the user node at the power supply end becomes a low-voltage user node, and the user changes from a normal user to a low-voltage user, that is, the second user number is obtained. The larger the power supply radius difference, the greater the second user number.

[0053] Step S204: Calculate the sum of the first number of users and the second number of users to obtain the target number of users.

[0054] Specifically, the original number of low-voltage first users and the newly added number of low-voltage second users are added to obtain the total number of low-voltage users at the second moment, that is, the target number of users.

[0055] Through this embodiment, the number of low-voltage users can be determined by the power supply range of the transformer. With the application of the power grid, more and more equipment is added to the power grid, which requires a large amount of voltage to supply power. As the number of equipment that needs to be powered increases, the maximum power supply radius of the transformer will also decrease. As the power supply radius decreases, the voltage value obtained by the user node at the end of the power supply will become smaller and smaller, making the user node at the end of the power supply become a low-voltage user node (less than 198V is a low-voltage user node). Therefore, this solution can determine the number of low-voltage users in a single substation or area through the change of the power supply radius of the transformer, thereby solving the problem in the prior art that it is impossible to provide a reference basis for power supply companies to predict the low voltage situation in a single substation or area in advance.

[0056] Specifically, low voltage in the substation is generally concentrated at the end of the distribution and transformation power supply range, so the calculation and analysis of the power supply boundary range of the substation can understand the number and distribution of low-voltage users to a certain extent. The definition of low-voltage substations by power supply companies is that the low-voltage users they contain must exceed a certain number or proportion. Substations that meet this standard can be called low-voltage substations, so that power supply companies will invest in and approve projects for the substations. The overall project funds are generally issued in advance to solve the problems of existing and incremental low-voltage substations. The existing problem is the low-voltage substations that have been monitored to meet the standards, and the incremental problem is the low-voltage substations that may appear this year. This number is generally fuzzy estimated based on past experience, and there is no quantitative calculation and prediction. Therefore, scientific prediction of the number of low-voltage users and low-voltage substations is of great reference significance for accurately grasping the incremental low-voltage substations and issuing project investment amounts based on evidence.

[0057] Specifically, the above-mentioned scheme of the present application can quickly predict the number of low-voltage users in a single substation or area, and can provide a basis for power supply companies to list them as key monitoring targets, thereby facilitating power supply companies to intervene in advance and carry out preliminary work for low-voltage substation transformation.

[0058] Specifically, the solution of the present application utilizes the following voltage drop formula to determine the substation current within the predicted year, thereby calculating the power supply distance for the voltage to drop from the transformer output terminal U0 to the low voltage critical value of 198V. As the predicted current increases, the power supply distance will decrease under the same voltage drop, so low voltage will occur to users at the border.

[0059] In the specific implementation process, obtaining the power supply radius difference can be achieved through the following steps: obtaining a first current value, wherein the first current value is the phase current value of the transformer at the first moment; determining the first maximum power supply radius according to the first current value, wherein the first maximum power supply radius is a power supply radius greater than the preset voltage value that can be provided by the transformer at the first moment; determining a second current value according to the first current value, wherein the second current value is the phase current value of the transformer at the second moment; determining the second maximum power supply radius according to the second current value, wherein the second maximum power supply radius is a power supply radius greater than the preset voltage value that can be provided by the transformer at the second moment; calculating the difference between the first maximum power supply radius and the second maximum power supply radius to obtain the power supply radius difference.

[0060] In this scheme, as the number of devices that need to be powered increases, the maximum power supply radius of the transformer will also decrease. The power supply radius that the transformer can provide at the first moment and is greater than the preset voltage value can be subtracted from the power supply radius that the transformer can provide at the second moment and is greater than the preset voltage value. The difference between the two power supply radii can be obtained, and the number of second users added after the power supply is reduced can be further accurately determined later.

[0061] Specifically, assuming that the single-phase voltage output by the secondary side of the transformer is U0, the single-phase user will have a voltage drop loss ΔU when the load current is transmitted in the loop composed of the live wire and the neutral wire, which can be calculated by the voltage drop formula: ΔU=2*I*R (multiplied by 2 because each phase of the circuit is composed of the live wire and the neutral wire, so it is equivalent to 2 times the resistance from the power supply point to the power consumption point). According to the low voltage judgment standard, single-phase voltage values ​​below 198V are all low voltages. Therefore, the voltage value obtained by the terminal single-phase user after the voltage drop loss should be 198V. The voltage drop ΔU at this time should be the maximum allowable voltage drop, so the following relationship can be obtained: U0-ΔU=198, ΔU=2*I*R=U0-198, where R=ρ·L / S, substituting into the above formula, we can get:

[0062] (It is derived by substituting the resistance formula into the voltage drop formula to show which factors are related to the power supply distance L from the distribution transformer to the user end).

[0063] Among them, L represents the length of the wire from the secondary output terminal of the transformer to the user side, S represents the cross-section of the wire, I represents the magnitude of the current transmitted by the wire, ρ represents the resistivity of the wire, and R represents the resistance of the wire.

[0064] Specifically, from the above derivation, it can be concluded that when the voltage at the output end of the secondary side of the transformer is fixed, the voltage on the user side is related to the power supply distance L, the cross-section S of the wire, the magnitude of the current I and the resistivity ρ of the wire. When the voltage on the user side reaches the minimum critical value of the normal voltage of 198V, if the cross-section S of the wire, the magnitude of the current I and the resistivity ρ of the wire are known, then L at this time is the maximum power supply radius that the current transformer can provide to meet the normal voltage, recorded as L0. That is to say, within the circular range with the transformer as the center and a radius of L0, users can obtain a normal voltage greater than 198V. Outside the circle with a power supply distance greater than L0, users will experience low voltage. If it is predicted that the low-voltage line current of the transformer will increase to I in the next x years, the current of the transformer will increase to I X From the above formula, we can see that if the conductor cross-section S and resistivity ρ remain unchanged (that is, the transformer area remains the same without modification), the maximum power supply radius that the transformer can provide to meet the normal voltage will be reduced, which is recorded as L. x Therefore, the distribution is L0-L X Users in the system will be changed from normal voltage users to low voltage users, such as Figure 3 As shown in the figure, the star represents the user node that is squeezed out of the normal voltage supply radius, L1 represents the current maximum normal voltage supply radius (it can also be L0, the first maximum power supply radius), L X It indicates the power supply radius with the largest normal voltage predicted after the xth year (i.e. the second largest power supply radius).

[0065] In a specific implementation process, obtaining the first current value can be achieved by the following steps: calculating the first current value according to a first formula, wherein the first formula is:

[0066]

[0067] I0 represents the first current value, R represents the resistance value of the transformer, η% represents the maximum load rate of the transformer at the first moment, and n represents the number of outgoing line loops of the transformer at the first moment. The above formula is only exemplary, and any variation of the formula falls within the protection scope of this application.

[0068] In this scheme, the first current value of each phase of the transformer is currently I0. When the three-phase current of the transformer is balanced, the actual phase current of the transformer can be calculated from the resistance value of the transformer (which can also be called capacity), the maximum load rate and the number of low-voltage outgoing line loops to obtain the first current value. Through this scheme, a more accurate first current value can be obtained.

[0069] Specifically, in the above formula, the cross-section S and resistivity ρ of the low-voltage line in the substation can be obtained from the basic data of the substation. The current current of each phase of the transformer is set to I0. Assuming that when the three-phase current of the transformer is balanced, the actual phase current of the transformer can be obtained by the transformer capacity (that is, the resistance value R of the transformer), the load rate and the number of low-voltage outgoing line loops, and the first formula is obtained, in which η% is the maximum load rate of the transformer in the normal operating mode of the year, and n can also represent the low-voltage outgoing line loop.

[0070] Specifically, according to the distribution transformer capacity and line current formula (In this solution, the capacity is represented by R, and the line voltage in the formula is 0.4kV) It is concluded that the rated current of the distribution transformer is:

[0071]

[0072] When the load rate of the distribution transformer is η%, and the low-voltage outgoing line circuit is n, the line current of the distribution transformer is:

[0073]

[0074] In a specific implementation process, determining the first maximum power supply radius according to the first current value can be achieved by the following steps: calculating the first maximum power supply radius according to a second formula, wherein the second formula is:

[0075]

[0076] L0 represents the first maximum power supply radius, U0 represents the single-phase voltage value output by the transformer, S represents the cross-section of the wire transmitted by the transformer, and ρ represents the resistivity of the wire transmitted by the transformer. The above formula is only exemplary, and any variation of the formula falls within the protection scope of this application.

[0077] In this solution, according to the first current value, by substituting it into the second formula, the first maximum power supply radius can be calculated, that is, the maximum radius at which the current transformer can supply power with normal voltage. Through this solution, a more accurate first maximum power supply radius can be obtained.

[0078] In some embodiments, determining the second current value according to the first current value can be specifically implemented by the following steps: calculating the second current value according to a third formula, wherein the third formula is:

[0079]

[0080] I X represents the second current value, α represents the natural growth rate of load, dp i represents the reported load of the above user node for a single phase, β iThe coefficient representing the reported load, Indicates the power factor of the reported load, sp i The above formula is only exemplary, and any variation of the formula falls within the protection scope of this application.

[0081] In this solution, the third formula defined in this application can be used to predict the current value I of each phase of the transformer in the xth planning year: X , that is, the second current value. The increased current includes the natural growth part and the load part of the newly added package. Through this solution, a more accurate second current value can be obtained.

[0082] Specifically, the above parameters are explained:

[0083] I X : Predict the current of each phase of the transformer in the xth planning year, that is, the second current value;

[0084] I0: the current of each phase of the current transformer, that is, the first current value;

[0085] α: natural growth rate of load, which is determined by the load base of the forecast area and the level of economic development, and is generally 2%-6%;

[0086] dp i : From the current time to the predicted x-th planning year, the i-th reported single-phase user reports the load in the planning year (i=1, 2...N), assuming that the reported single-phase load is evenly connected to the three-phase conductor of each outgoing line of the transformer;

[0087] sp i : From the current time to the predicted x-th planning year, the i-th three-phase user reports the load in the planning year (i=1, 2...N), assuming that the reported three-phase load is evenly connected to each outgoing line of the transformer;

[0088] : The power factor of the i-th registered user;

[0089] β i : Utility coefficient of the ith registered user (i=1, 2...N). The utility coefficient is the stable load value divided by the registered capacity. The selection of the utility coefficient should be verified based on the load development of mature users of the same type in the region. The recommended values ​​of the utility coefficients for residential, commercial, industrial and other load types are 0.35, 0.4, 0.7 and 0.4 respectively.

[0090] Specifically, the first part of the third formula above is the current value predicted after the natural growth of the load, I0 is the current current, α is the natural growth rate of the distribution transformer load, then the load current next year is I0*(1+α), and the load current the year after is I0*(1+α) 2 , and so on, in the forecasted x-th planning year, the distribution transformer load current is I0*(1+α) X The second part of the formula is to calculate the additional current of the newly registered single-phase users. The registered capacity of each user is dp i , the utility coefficient is β i , then the actual capacity of each newly registered single-phase user is dp*β i , then the single-phase capacity and voltage and current (U takes 0.22V) and the single-phase user current is obtained as follows: Sum up the currents of all registered single-phase users, assuming that they are all evenly connected to the three-phase conductors of each outgoing line of the transformer, which is 3*n outgoing lines in total, so the denominator is 3*n. The third part of the formula is to calculate the additional current of the newly registered three-phase users. The basic idea is the same as the second part to calculate the current of single-phase users. The difference is that the current calculated by the three-phase user is the three-phase current, and it is assumed that they are evenly connected to n outgoing lines, so the denominator is n.

[0091] In some embodiments, determining the second maximum power supply radius according to the second current value can be specifically implemented by the following steps: calculating the second maximum power supply radius according to a fourth formula, wherein the fourth formula is:

[0092]

[0093] L x The above formula is only exemplary, and any variation of the formula falls within the protection scope of this application.

[0094] In this scheme, by substituting the second current value into the fourth formula, it is possible to predict the power supply radius L of the normal voltage that the transformer can provide in the xth planning year. x , that is, the second maximum power supply radius. Through this solution, a more accurate second maximum power supply radius can be obtained.

[0095] Specifically, the second and fourth formulas show that in the xth planning year, the normal voltage supply radius that the transformer can provide is reduced from L0 to L X , recorded as ΔL, users in ΔL will become low-voltage users.

[0096] In some embodiments, determining the number of second users at the second moment according to the power supply radius difference may be implemented by the following steps: calculating the number of second users according to the fifth formula, wherein the fifth formula is:

[0097]

[0098] D represents the number of the second users, W represents the number of the first users, and L M represents the maximum power supply radius of the transformer at present, and ΔL represents the power supply radius difference. The above formula is only exemplary, and any variation of the formula falls within the protection scope of this application.

[0099] In this solution, based on the average distribution of transformer locations, the number of second users within the power supply radius difference can be roughly estimated, and the number of newly added user nodes can be obtained through the fifth formula, which further solves the problem in the prior art that it is impossible to provide a reference basis for power supply companies to predict low voltage conditions in a single substation or area in advance.

[0100] Specifically, since the distribution of the number of users from the transformer location is affected by many factors, such as the development of the village, the restrictions on the plot, the location of the transformer, etc., the distribution pattern of the number of users in each substation is different. Therefore, the number of users in ΔL can only be roughly estimated. Assuming that the distance between users and the transformer is evenly distributed, assuming that the total number of low-voltage users in the substation is W, and the farthest power supply radius of the substation is L M , then the average number of users per 1 meter of power supply distance is Therefore, we can roughly estimate the number of users in ΔL, that is, by the xth planning year, we predict the number of new low-voltage users D that will be added in the substation.

[0101] Substituting the second and fourth formulas into the fifth formula, we can get:

[0102]

[0103] In the above formula, the number of low-voltage users in the area is W, and the farthest power supply radius of the area is L. M , transformer output voltage U0, low voltage conductor cross section S, number of low voltage outgoing lines n, transformer capacity R, maximum load rate η%, conductor resistivity ρ, load natural growth rate α, utility coefficient β of the reported user, power factor Newly installed single-phase load dp i and three-phase load sp iThey can all be obtained from the basic data of the substation and the statistics of the work orders reported. The predicted number of new low-voltage users D in the substation can be determined by calculation. When the predicted number D reaches a certain level, the power supply company can list it as a key low-voltage monitoring target and intervene in advance to prevent low voltage phenomena in the later stage.

[0104] In addition, in the solution of this application, multiple factors need to be considered to determine the reduction degree of the transformer power supply radius, including the rated power of the transformer, the power supply line voltage, the power supply line current, the resistance and reactance of the transmission line, the terrain and the environment, etc. The reduction of the power supply radius can be evaluated by the following steps:

[0105] Calculate based on the rated power and rated voltage of the transformer. Calculate the voltage drop based on the load of the distribution line and the resistance loss of the transmission line: This requires considering the resistance, reactance and current of the line. Based on the rated capacity of the transformer and the calculated voltage drop, the maximum distance that the transformer can normally supply power under ideal conditions can be obtained;

[0106] When the voltage is high, the power supply radius can be increased accordingly; when the voltage is low, the power supply radius should be reduced. When the current is large, the power supply radius will decrease due to wire loss and voltage reduction. The greater the resistance and reactance, the greater the power loss, and the power supply radius should be reduced accordingly. For example, in mountainous or swampy areas, due to complex environmental conditions, the power supply radius may be reduced. When the load rate is high, the influence of the distribution line increases, and the power supply radius may be reduced;

[0107] Assuming that a transformer has a rated power of 100kVA and a rated voltage of 400V, under ideal conditions (i.e., without considering other influencing factors), its power supply radius may be initially determined to be 500 meters. If the actual power supply line voltage drops to 380V, the power supply radius may need to be reduced by 10%, that is, to 450 meters, due to the voltage reduction. If the power supply line current is large, assuming that it reaches 80% of the rated current, the power supply radius may need to be reduced by another 5%, that is, to 427.5 meters, due to increased wire losses. If the transformer is located in a mountainous area, due to the complex terrain, the power supply radius may need to be reduced by another 5%, that is, to 406 meters.

[0108] In addition, when the transformer capacity is insufficient due to the increase in user load, the transformer capacity should be increased. This needs to be evaluated and predicted according to the user load. For example, the original transformer capacity is 500kVA, and it is planned to be upgraded to 800kVA to meet the growing user load demand. After the upgrade, the transformer can carry a larger load without causing voltage drop.

[0109] In addition, when the transformer is supplying power at low voltage, if the power supply quality is poor, the load can be distributed reasonably to avoid overloading some areas and causing voltage drops. The load can be monitored and adjusted in real time through smart meters and monitoring systems. If the load continues to grow, consider upgrading the transformer capacity to meet the demand. For example, upgrade a 500kVA transformer to 800kVA to carry a larger load.

[0110] In addition, the power supply radius is defined as the distance from the transformer to the farthest electrical device, which is related to the relationship between the rated voltage of the transformer and the rated power of the farthest electrical device.

[0111] In summary, this solution is to reversely apply the voltage drop formula, derive the farthest power supply radius of the transformer providing normal voltage according to the maximum allowable value of the voltage drop, and derive the difference of the farthest power supply radius according to the difference of the maximum load current carried by the transformer in different periods. The users within the difference are predicted to be prone to low voltage. The calculation of the predicted load current is more reasonable and accurate. The predicted load current is divided into a natural growth part and a new application part. The new application is divided into a single-phase application current and a three-phase application current, and calculated separately. Compared with the existing technology, this solution can quickly predict the number and distribution of low-voltage users that may appear in the substation in the future. This method can not only predict a single substation, but also predict and analyze multiple substations in the region at the same time. This method allows power supply companies to quantitatively analyze the possible low voltage in the region in the future, advance the threshold of low voltage management, and be "prepared for a rainy day."

[0112] The scheme of this application has been applied to actual areas. The definition of low-voltage areas in Province X is that when the number of low-voltage users in the area exceeds 10 or the proportion of low-voltage users in the area to the total number of users in the area is 20% or more, the area is a low-voltage area. Therefore, the method of this scheme is used to predict the number of low-voltage users in each area. When the above judgment criteria are met, it is equivalent to predicting the number of low-voltage areas.

[0113] The scheme of the present application is used to predict the number of low-voltage substations in Province X in 2022 and 2023 (that is, prediction is made based on the basic data of the substations at that time and the installation work orders in 22 and 23). It is calculated that 1,879 new low-voltage substations are predicted in 2022, and the actual number is 1,823, with a deviation of 56 units, and a deviation rate of 3.07%; it is calculated that 1,413 new low-voltage substations are predicted in 2023, and the actual number is 1,348, with a deviation of 65 units, and a deviation rate of 4.82%, thus proving that the method is feasible.

[0114] The embodiment of the present application also provides a device for determining the number of users of a low voltage. It should be noted that the device for determining the number of users of a low voltage in the embodiment of the present application can be used to perform the method for determining the number of users of a low voltage provided in the embodiment of the present application. The device is used to implement the above-mentioned embodiments and preferred implementations, and those that have been described will not be repeated. As used below, the term "module" can implement a combination of software and / or hardware of a predetermined function. Although the device described in the following embodiments is preferably implemented in software, the implementation of hardware, or a combination of software and hardware is also possible and conceived.

[0115] The following introduces a device for determining the number of low-voltage users provided in an embodiment of the present application.

[0116] Figure 4 is a structural block diagram of a device for determining the number of low-voltage users according to an embodiment of the present application. Figure 4 As shown, the device comprises:

[0117] A first acquisition unit 10 is used to acquire the first number of users at a first moment, wherein the first number of users is the number of user nodes whose voltage value is less than or equal to a preset voltage value in the power supply area of ​​the transformer at the first moment;

[0118] A second acquisition unit 20 is used to acquire a power supply radius difference, wherein the power supply radius difference is a difference between a first maximum power supply radius of the transformer at the first moment and a second maximum power supply radius of the transformer at a second moment, and the first moment is earlier than the second moment;

[0119] A determination unit 30 is configured to determine the number of second users at the second moment according to the power supply radius difference, wherein the number of second users is the number of newly added user nodes whose voltage value is less than or equal to the preset voltage value in the power supply area of ​​the transformer at the second moment, wherein the power supply radius difference is positively correlated with the number of second users;

[0120] The calculation unit 40 is used to calculate the sum of the first number of users and the second number of users to obtain the target number of users.

[0121] Through this embodiment, the number of low-voltage users can be determined by the power supply range of the transformer. With the application of the power grid, more and more equipment is added to the power grid, which requires a large amount of voltage to supply power. As the number of equipment that needs to be powered increases, the maximum power supply radius of the transformer will also decrease. As the power supply radius decreases, the voltage value obtained by the user node at the end of the power supply will become smaller and smaller, making the user node at the end of the power supply become a low-voltage user node (less than 198V is a low-voltage user node). Therefore, this solution can determine the number of low-voltage users in a single substation or area through the change of the power supply radius of the transformer, thereby solving the problem in the prior art that it is impossible to provide a reference basis for power supply companies to predict the low voltage situation in a single substation or area in advance.

[0122] In the specific implementation process, the second acquisition unit includes an acquisition module, a first determination module, a second determination module, a third determination module and a first calculation module, the acquisition module is used to acquire the first current value, wherein the first current value is the phase current value of the transformer at the first moment; the first determination module is used to determine the first maximum power supply radius according to the first current value, wherein the first maximum power supply radius is the power supply radius that can be provided by the transformer at the first moment and is greater than the preset voltage value; the second determination module is used to determine the second current value according to the first current value, wherein the second current value is the phase current value of the transformer at the second moment; the third determination module is used to determine the second maximum power supply radius according to the second current value, wherein the second maximum power supply radius is the power supply radius that can be provided by the transformer at the second moment and is greater than the preset voltage value; the first calculation module is used to calculate the difference between the first maximum power supply radius and the second maximum power supply radius to obtain the power supply radius difference.

[0123] In this scheme, as the number of devices that need to be powered increases, the maximum power supply radius of the transformer will also decrease. The power supply radius that the transformer can provide at the first moment and is greater than the preset voltage value can be subtracted from the power supply radius that the transformer can provide at the second moment and is greater than the preset voltage value. The difference between the two power supply radii can be obtained, and the number of second users added after the power supply is reduced can be further accurately determined later.

[0124] In a specific implementation process, the acquisition module includes a first calculation submodule, and the first calculation submodule is used to calculate the first current value according to a first formula, wherein the first formula is:

[0125]

[0126] I0 represents the first current value, R represents the resistance value of the transformer, η% represents the maximum load rate of the transformer at the first moment, and n represents the number of outgoing line loops of the transformer at the first moment. The above formula is only exemplary, and any variation of the formula falls within the protection scope of this application.

[0127] In this scheme, the first current value of each phase of the transformer is currently I0. When the three-phase current of the transformer is balanced, the actual phase current of the transformer can be calculated from the resistance value of the transformer (which can also be called capacity), the maximum load rate and the number of low-voltage outgoing line loops to obtain the first current value. Through this scheme, a more accurate first current value can be obtained.

[0128] In a specific implementation process, the first determination module includes a second calculation submodule, and the second calculation submodule is used to calculate the first maximum power supply radius according to a second formula, wherein the second formula is:

[0129]

[0130] L0 represents the first maximum power supply radius, U0 represents the single-phase voltage value output by the transformer, S represents the cross-section of the wire transmitted by the transformer, and ρ represents the resistivity of the wire transmitted by the transformer. The above formula is only exemplary, and any variation of the formula falls within the protection scope of this application.

[0131] In this solution, according to the first current value, by substituting it into the second formula, the first maximum power supply radius can be calculated, that is, the maximum radius at which the current transformer can supply power with normal voltage. Through this solution, a more accurate first maximum power supply radius can be obtained.

[0132] In some embodiments, the second determination module includes a third calculation submodule, and the third calculation submodule is used to calculate the second current value according to a third formula, wherein the third formula is:

[0133]

[0134] I X represents the second current value, α represents the natural growth rate of load, dp i represents the reported load of the above user node for a single phase, β i The coefficient representing the reported load, Indicates the power factor of the reported load, sp i The above formula is only exemplary, and any variation of the formula falls within the protection scope of this application.

[0135] In this solution, the third formula defined in this application can be used to predict the current value I of each phase of the transformer in the xth planning year:X , that is, the second current value. The increased current includes the natural growth part and the load part of the newly added package. Through this solution, a more accurate second current value can be obtained.

[0136] In some embodiments, the third determination module includes a fourth calculation submodule, and the fourth calculation submodule is used to calculate the second maximum power supply radius according to a fourth formula, wherein the fourth formula is:

[0137]

[0138] L x The above formula is only exemplary, and any variation of the formula falls within the protection scope of this application.

[0139] In this scheme, by substituting the second current value into the fourth formula, it is possible to predict the power supply radius L of the normal voltage that the transformer can provide in the xth planning year. x , that is, the second maximum power supply radius. Through this solution, a more accurate second maximum power supply radius can be obtained.

[0140] In some embodiments, the determination unit includes a second calculation module, and the second calculation module is used to calculate the number of the second users according to a fifth formula, wherein the fifth formula is:

[0141]

[0142] D represents the number of the second users, W represents the number of the first users, and L M represents the maximum power supply radius of the transformer at present, and ΔL represents the power supply radius difference. The above formula is only exemplary, and any variation of the formula falls within the protection scope of this application.

[0143] In this solution, based on the average distribution of transformer locations, the number of second users within the power supply radius difference can be roughly estimated, and the number of newly added user nodes can be obtained through the fifth formula, which further solves the problem in the prior art that it is impossible to provide a reference basis for power supply companies to predict low voltage conditions in a single substation or area in advance.

[0144] The above-mentioned device for determining the number of low-voltage users includes a processor and a memory, and the above-mentioned first acquisition unit, second acquisition unit, determination unit and calculation unit are all stored in the memory as program units, and the processor executes the above-mentioned program units stored in the memory to implement corresponding functions. The above-mentioned modules are all located in the same processor; or, the above-mentioned modules are located in different processors in any combination.

[0145] The processor includes a kernel, which calls the corresponding program unit from the memory. One or more kernels can be set, and the kernel parameters can be adjusted to solve the problem that the existing technology cannot predict the number of low-voltage users in multiple substations in the region, and cannot provide a reference for power supply companies to predict the low voltage situation in a single substation or area in advance.

[0146] The memory may include non-permanent memory in a computer-readable medium, random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM, and the memory includes at least one memory chip.

[0147] An embodiment of the present invention provides a computer-readable storage medium, wherein the computer-readable storage medium includes a stored program, wherein when the program is executed, the device where the computer-readable storage medium is located is controlled to execute the method for determining the number of low-voltage users.

[0148] An embodiment of the present invention provides a processor, and the processor is used to run a program, wherein the method for determining the number of low-voltage users is executed when the program is run.

[0149] An embodiment of the present invention provides a device, which includes a processor, a memory, and a program stored in the memory and executable on the processor. When the processor executes the program, at least the steps of a method for determining the number of low-voltage users are implemented.

[0150] The devices in this article can be servers, PCs, PADs, mobile phones, etc.

[0151] A computer program product includes a non-volatile computer-readable storage medium, wherein the non-volatile computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the method for determining the number of low-voltage users in each embodiment of the present application are implemented.

[0152] The present application also provides a user quantity determination system, comprising one or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and are configured to be executed by the one or more processors, and the one or more programs include methods for executing any of the above-mentioned low-voltage user quantity determination methods.

[0153] Obviously, those skilled in the art should understand that the above modules or steps of the present invention can be implemented by a general computing device, they can be concentrated on a single computing device, or distributed on a network composed of multiple computing devices, they can be implemented by a program code executable by a computing device, so that they can be stored in a storage device and executed by the computing device, and in some cases, the steps shown or described can be executed in a different order than here, or they can be made into individual integrated circuit modules, or multiple modules or steps therein can be made into a single integrated circuit module for implementation. Thus, the present invention is not limited to any specific combination of hardware and software.

[0154] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0155] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0156] These computer program instructions may also be stored in a computer readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture including an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0157] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process in the computer or other programmable device. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0158] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0159] The memory may include non-permanent memory in a computer-readable medium, random access memory (RAM) and / or non-volatile memory in the form of read-only memory (ROM) or flash RAM. The memory is an example of a computer-readable medium.

[0160] Computer readable media include permanent and non-permanent, removable and non-removable media that can be implemented by any method or technology to store information. Information can be computer readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, compact disk read-only memory (CD-ROM), digital versatile disk (DVD) or other optical storage, magnetic cassettes, magnetic disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined herein, computer readable media does not include temporary computer readable media (transitory media), such as modulated data signals and carrier waves.

[0161] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity 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, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0162] From the above description, it can be seen that the above embodiments of the present application achieve the following technical effects:

[0163] 1) The method for determining the number of low-voltage users of the present application can determine the number of low-voltage users by the power supply range of the transformer. With the application of the power grid, more and more equipment is added to the power grid, which requires a large amount of voltage to supply power. As the number of equipment that needs to be powered increases, the maximum power supply radius of the transformer will also decrease. As the power supply radius decreases, the voltage value obtained by the user node at the end of the power supply will become smaller and smaller, making the user node at the end of the power supply become a low-voltage user node (less than 198V is a low-voltage user node). Therefore, this scheme can determine the number of low-voltage users in a single substation or area by changing the power supply radius of the transformer, thereby solving the problem in the prior art that it is impossible to provide a reference basis for power supply companies to predict the low voltage situation in a single substation or area in advance.

[0164] 2) The device for determining the number of low-voltage users of the present application can determine the number of low-voltage users through the power supply range of the transformer. With the application of the power grid, more and more equipment is added to the power grid, which requires a large amount of voltage to supply power. As the number of equipment that needs to be powered increases, the maximum power supply radius of the transformer will also decrease. As the power supply radius decreases, the voltage value obtained by the user node at the end of the power supply will become smaller and smaller, making the user node at the end of the power supply become a low-voltage user node (less than 198V is a low-voltage user node). Therefore, this scheme can determine the number of low-voltage users in a single substation or area through the change of the power supply radius of the transformer, thereby solving the problem in the prior art that it is impossible to provide a reference basis for power supply companies to predict the low voltage situation in a single substation or area in advance.

[0165] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for determining the number of low voltage users, characterized in that: include: Acquire a first number of users at a first moment, wherein the first number of users is the number of user nodes whose voltage value is less than or equal to a preset voltage value in a power supply area of ​​the transformer at the first moment; Obtaining a power supply radius difference, wherein the power supply radius difference is a difference between a first maximum power supply radius of the transformer at the first moment and a second maximum power supply radius of the transformer at the second moment, the first moment being earlier than the second moment; Determine the number of second users at the second moment according to the power supply radius difference, wherein the second number of users is the number of newly added user nodes whose voltage value is less than or equal to the preset voltage value in the power supply area of ​​the transformer at the second moment, wherein the power supply radius difference and the second number of users are positively correlated; The sum of the first number of users and the second number of users is calculated to obtain the target number of users.

2. The method according to claim 1, characterized in that: Get the power supply radius difference, including: Acquire a first current value, wherein the first current value is a phase current value of the transformer at the first moment; Determining the first maximum power supply radius according to the first current value, wherein the first maximum power supply radius is a power supply radius that can be provided by the transformer at the first moment and is greater than the preset voltage value; Determine a second current value according to the first current value, wherein the second current value is a phase current value of the transformer at the second moment; Determining the second maximum power supply radius according to the second current value, wherein the second maximum power supply radius is a power supply radius that can be provided by the transformer at the second moment and is greater than the preset voltage value; A difference between the first maximum power supply radius and the second maximum power supply radius is calculated to obtain the power supply radius difference.

3. The method according to claim 2, characterized in that Obtaining a first current value includes: The first current value is calculated according to a first formula, wherein the first formula is: I0 represents the first current value, R represents the resistance value of the transformer, η% represents the maximum load rate of the transformer at the first moment, and n represents the number of outgoing line loops of the transformer at the first moment.

4. The method according to claim 2, characterized in that: Determining the first maximum power supply radius according to the first current value includes: The first maximum power supply radius is calculated according to a second formula, wherein the second formula is: L0 represents the first maximum power supply radius, U0 represents the single-phase voltage value output by the transformer, S represents the cross-section of the conductor transmitted by the transformer, and ρ represents the resistivity of the conductor transmitted by the transformer.

5. The method according to claim 2, characterized in that: Determining a second current value according to the first current value includes: The second current value is calculated according to a third formula, wherein the third formula is: I X represents the second current value, α represents the natural growth rate of load, dp i represents the reported load of the user node of a single phase, β i The coefficient representing the reported load, Indicates the power factor of the reported load, sp i Represents the reported load of the user node of the three phases.

6. The method according to claim 2, characterized in that Determining the second maximum power supply radius according to the second current value includes: The second maximum power supply radius is calculated according to a fourth formula, wherein the fourth formula is: L x Indicates the second maximum power supply radius.

7. The method according to claim 2, characterized in that: Determining the number of second users at the second moment according to the power supply radius difference includes: The second number of users is calculated according to the fifth formula, wherein the fifth formula is: D represents the number of the second users, W represents the number of the first users, and L M represents the current maximum power supply radius of the transformer, and ΔL represents the power supply radius difference.

8. A device for determining the number of low-voltage users, characterized in that: include: A first acquisition unit, configured to acquire a first number of users at a first moment, wherein the first number of users is the number of user nodes whose voltage value is less than or equal to a preset voltage value in a power supply area of ​​the transformer at the first moment; a second acquiring unit, configured to acquire a power supply radius difference, wherein the power supply radius difference is a difference between a first maximum power supply radius of the transformer at the first moment and a second maximum power supply radius of the transformer at a second moment, the first moment being earlier than the second moment; a determining unit, configured to determine the number of second users at the second moment according to the power supply radius difference, wherein the second number of users is the number of newly added user nodes whose voltage value is less than or equal to the preset voltage value in the power supply area of ​​the transformer at the second moment, wherein the power supply radius difference and the second number of users are positively correlated; A calculation unit is used to calculate the sum of the first number of users and the second number of users to obtain a target number of users.

9. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the method for determining the number of low-voltage users as claimed in any one of claims 1 to 7 are implemented.

10. A system for determining the number of users, 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 are configured to be executed by the one or more processors, and the one or more programs include a method for determining the number of low-voltage users as described in any one of claims 1 to 7.

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