Low-voltage business expansion access method, low-voltage business expansion access method device, computer equipment and computer-readable storage medium

Abstract

The embodiment of the present application discloses a low-voltage business expansion access method, a low-voltage business expansion access method device, a computer device and a computer-readable storage medium. The method includes the following steps: obtaining low-voltage substation topology map data to construct a substation node model, the substation node model includes multiple nodes; obtaining the flow data of the nodes in the substation node model within a predetermined time period; bringing the flow data into the node model to solve the flow voltage of the node, and summarizing the flow voltage to construct a voltage drop model; obtaining the access demand of the business expansion load, bringing the access demand into the voltage drop model to obtain the access plan and output it. Therefore, the present application can construct a voltage drop model that reflects the voltage change in the back-end area after the load is connected, and then use the demand of the load that needs to be connected to predict the voltage change in the back-end area after the load is connected to the node to obtain the access plan and output it, which solves the defect in the prior art that there is no flow calculation to solve the optimal access plan for low-voltage business expansion.

Description

Technical Field

[0001] The present application belongs to the technical field of power distribution systems, and in particular relates to a low-voltage business expansion access method, a low-voltage business expansion access method device, a computer device, and a computer-readable storage medium. Background Art

[0002] The low-voltage distribution system is located at the end of the power system and is the last mile connecting the power system and power users. The load characteristics of the low-voltage distribution network are becoming increasingly complex, and voltage stability issues are becoming prominent. Especially during business expansion, the connection of new loads may cause local voltage drops, affecting power supply quality. Currently, there is no technical guidance for low-voltage business expansion and renovation work. The "connection first, then governance" principle is still adopted on site. There is no predictive method to support whether the new load can meet customer electricity demand after connection. The open capacity calculated according to the empirical formula can no longer measure the actual load capacity of the distribution network, and it is difficult to play the role of the grid in expanding and supporting the open capacity of distribution. How to scientifically and reasonably predict the voltage drop after load connection is a technical problem that needs to be solved urgently by those skilled in the art.

[0003] The preceding description is intended to provide general background information and does not necessarily constitute prior art. Summary of the Invention

[0004] Based on this, it is necessary to address the above problems and propose a low-voltage business expansion access method, a low-voltage business expansion access method device, a computer device and a computer-readable storage medium, which can effectively predict the optimal solution for new loads to access the power grid.

[0005] The present application solves the technical problem by adopting the following technical solutions:

[0006] The present application provides a low-voltage business expansion access method, including the following steps: obtaining low-voltage substation topology map data to construct a substation node model, the substation node model includes multiple nodes; obtaining the flow data of the nodes in the substation node model within a predetermined time period; bringing the flow data into the node model to solve the flow voltage of the node, and summarizing the flow voltage to construct a voltage drop model; obtaining the access requirements of the business expansion load, bringing the access requirements into the voltage drop model to obtain an access plan and output it.

[0007] In an optional embodiment of the present application, a substation node model is constructed, including: constructing a substation node intermediate model based on low-voltage substation topology data, the substation node intermediate model including a substation transformer and multiple user nodes; obtaining line information and voltage information of the user node based on the low-voltage substation topology data, and calculating one by one whether the node merging conditions are met between multiple user nodes based on the line information and voltage information; if the node merging conditions are met between multiple user nodes, a merge mark is assigned to the user nodes that meet the node merging conditions; if the node merging conditions are not met between multiple user nodes, an independent mark is assigned to the user nodes that do not meet the node merging conditions; the user nodes in the substation node intermediate model are merged according to the merge mark, and the user nodes with independent marks are retained; the sorted user nodes and substation transformers are marked as nodes to obtain the substation node model.

[0008] In an optional embodiment of the present application, whether the node merging conditions are met between multiple user nodes is calculated one by one according to the line information and voltage information, including: the line information includes the transformer length and overlapping length of each user node, the transformer length is used to indicate the line length from the user node to the substation transformer, and the overlapping length is used to indicate the line length of all overlapping parts from the user node to the substation transformer; the adjacency index between each user node is calculated according to the transformer length and overlapping length; when the adjacency index is less than or equal to a preset similarity threshold, it is determined that the user node does not meet the node merging conditions; when the adjacency index is greater than the preset similarity threshold, the user node is marked as an intermediate node; voltage information is obtained, the voltage information includes the node voltage value of the intermediate node at time p, and the average substation voltage value at time p, where p is an arbitrary constant; the similarity index of the intermediate node is calculated according to the node voltage value and the average substation voltage value; when the similarity index is less than or equal to the preset similarity threshold, it is determined that the intermediate node does not meet the node merging conditions; when the similarity index is greater than the preset similarity threshold, it is determined that the intermediate node meets the node merging conditions.

[0009] In an optional embodiment of the present application, the flow data is brought into the node model to solve the flow voltage of the node, including: obtaining the flow data of the node during the heavy load period of the transformer, the flow data including the node voltage, node active power and node reactive power; writing the node voltage equation according to the flow data, and using a preset method to solve the node voltage equation to obtain the flow voltage.

[0010] In an optional embodiment of the present application, a node voltage equation is written based on the power flow data, and the node voltage equation is solved using a preset method to obtain the power flow voltage, including: treating the first node in the node as a balance node and the remaining nodes as PQ nodes, and writing the node voltage equation based on the power flow data:

[0011]

[0012] Y nn is the self-admittance of the corresponding node, Y 1n 、Y n1 is the mutual admittance between nodes 1 and n; is the node voltage; P n is the node active power; Q n is the node reactive power; j is the imaginary unit in the complex number, j 2 =-1; the iterative solution equation can be obtained by using the forward-backward method to solve the node voltage equation. The iterative solution equation is expressed as:

[0013]

[0014] Iterative calculation solves the equations iteratively until the voltage calculation results of all nodes in the iterative solution of the equations converge, and the converged calculation results of the nodes are marked as power flow voltages.

[0015] In an optional embodiment of the present application, the node voltage equation is iteratively calculated until the voltage calculation results of all nodes in the node voltage equation converge, including: ignoring the influence of the phase angle difference within the node voltage on the amplitude, replacing the node voltage with a simplified voltage, where the simplified voltage only takes the amplitude of the node voltage, and the simplified voltage is expressed as:

[0016]

[0017] Substitute the simplified voltage into the iterative solution equation to obtain the simplified solution equation, which is expressed as:

[0018]

[0019] The simplified solution equation is solved iteratively until the voltage calculation results of all nodes in the simplified solution equation converge.

[0020] In an optional embodiment of the present application, the access demand is brought into the voltage drop model to obtain the access plan and output it, including: determining the access mode according to the access demand, the access mode includes a first access mode and a second access mode; when the access mode is the first access mode, obtaining the access load in the access demand, bringing the access load into the voltage drop model, calculating the first voltage drop value generated after the load is connected to all nodes, generating the access plan according to the first voltage drop value and outputting it; when the access mode is the second access mode, obtaining the branch line modification plan and access load in the access demand, modifying the voltage drop model according to the branch line modification plan; bringing the access load into the modified voltage drop model, calculating the second voltage drop value generated after the load is connected to all nodes, generating the access plan according to the second voltage drop value and outputting it.

[0021] The present application also provides a low-voltage business expansion access device, including: a modeling module, used to obtain low-voltage substation topology map data to construct a substation node model, the substation node model includes multiple nodes; a calculation module, used to obtain the flow data of the nodes in the substation node model within a predetermined time period; the flow data is brought into the node model to solve the flow voltage of the node, and the flow voltage is summarized to construct a voltage drop model; a simulation module, used to obtain the access requirements of the business expansion load, bring the access requirements into the voltage drop model to obtain the access plan and output it.

[0022] The present application also provides a computer device, comprising a processor and a memory: the processor is configured to execute a computer program stored in the memory to implement the aforementioned method.

[0023] The present application also provides a computer-readable storage medium storing a computer program, which implements the aforementioned method when the computer program is executed by a processor.

[0024] The embodiments of the present application have the following beneficial effects:

[0025] The present application can use the low-voltage substation topology data to build a substation solution model before the load is connected, and solve the current voltage to obtain a voltage drop model that reflects the voltage change in the back-end area after the load is connected. Then, using the demand of the load that needs to be connected, the voltage change in the back-end area of the load access node is predicted to obtain the access plan and output it, which solves the defect in the existing technology that there is no current calculation to solve the optimal access plan for low-voltage business expansion. At the same time, the characteristics of the low-voltage distribution network are also used in the calculation process to simplify the iteration and greatly reduce the amount of calculation.

[0026] The above description is only an overview of the technical solution of this application. In order to more clearly understand the technical means of this application, which can be implemented in accordance with the contents of the description, and to make the above and other purposes, features and advantages of this application more obvious and easy to understand, the following preferred embodiments are specifically described in detail with reference to the accompanying drawings. It should be understood that the above general description and the detailed description below are only exemplary and explanatory and do not limit this application. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0028] in:

[0029] Figure 1A flowchart of a low-voltage business expansion access method provided by an embodiment;

[0030] Figure 2 A diagram showing the relationship between internal functional modules of a low-voltage business expansion access method and device provided by one embodiment;

[0031] Figure 3 The present invention is a schematic block diagram of the structure of a computer device provided by an embodiment. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0033] In the existing business expansion process, the access of new loads may cause local voltage drops and affect the power supply quality. At present, there is no technical guidance for low-voltage business expansion and expansion and renovation work. The on-site still adopts the "first access, then governance" principle. There is no prediction method to support whether the new load can meet the customer's electricity demand after access; or the open capacity calculated according to the empirical formula cannot continue to measure the actual load capacity of the distribution network, and it is difficult to play the role of the grid in expanding and supporting the open capacity of the distribution network. For this reason, this application proposes a low-voltage business expansion access method for scientifically and reasonably predicting the voltage drop after the load is connected, and using the access plan with the least impact on the output load to guide the low-voltage business expansion. In order to clearly describe a low-voltage business expansion access method provided in this embodiment, please refer to Figure 1 , including steps S110 to S130.

[0034] Step S110: obtaining low-voltage substation topology data to construct a substation node model, which includes a plurality of nodes.

[0035] In one embodiment, the low-voltage substation topology map data can be directly obtained by using the data collected by the existing electricity consumption information collection system, without installing any auxiliary equipment on site. Specifically, the low-voltage substation topology map data may include but is not limited to the topological wiring diagram of the distribution transformer, branch box, fire point and user location, as well as the length and model parameters of the line connecting each point. The acquired low-voltage substation topology map data will be used to construct a substation node model. The substation node model includes multiple nodes, and each node can be a transformer location, a user node location, etc. in a low-voltage substation. The substation node model is used to display the mathematical relationship between the connections of each node in the substation, which is convenient for analyzing and mining the correlation between each other, so as to complete the generation of the optimal business expansion plan for the low-voltage substation. Specifically, the method proposed in this application can be operated using an embedded system as an execution terminal, and can also be operated separately in the corresponding equipment, greatly improving the work efficiency of on-site staff.

[0036] In one embodiment, step S110: constructing a substation node model, including: constructing a substation node intermediate model based on low-voltage substation topology data, the substation node intermediate model includes a substation transformer and multiple user nodes; obtaining line information and voltage information of the user node based on the low-voltage substation topology data, and calculating one by one whether the node merging conditions are met between multiple user nodes based on the line information and voltage information; if the node merging conditions are met between multiple user nodes, a merge mark is assigned to the user nodes that meet the node merging conditions; if the node merging conditions are not met between multiple user nodes, an independent mark is assigned to the user nodes that do not meet the node merging conditions; the user nodes in the substation node intermediate model are merged according to the merge mark, and the user nodes with independent marks are retained; the sorted user nodes and substation transformers are marked as nodes to obtain the substation node model.

[0037] In one embodiment, it is understandable that when analyzing the voltage drop change after a new load is connected to the substation, due to the large number of nodes in a substation, the amount of calculation will be very large and the difficulty of calculation will increase sharply. For this reason, the similar nodes in the substation can be merged to simplify the calculation complexity of the model. The specific simplification process can first construct an intermediate model of the substation node based on the low-voltage substation topology data. The intermediate model of the substation node is actually a substation model that includes all nodes in the substation. At this time, the intermediate model of the substation node includes a substation transformer and multiple user nodes. The user node is actually the user node corresponding to all users in the substation. If the intermediate model of the substation node is analyzed and calculated at this time, the amount of calculation will be extremely large, and it will be difficult to quickly obtain the analysis results. For this reason, the similar user nodes can be merged to simplify the calculation complexity.

[0038] Specifically, the line information and voltage information of the user nodes can be obtained, and whether the node merging conditions are met between multiple user nodes can be calculated one by one based on the line information and voltage information.

[0039] In one embodiment, whether a node merging condition is satisfied between multiple user nodes is calculated one by one based on line information and voltage information, including: the line information includes the transformer length and overlapping length of each user node, the transformer length is used to indicate the line length from the user node to the transformer in the substation, and the overlapping length is used to indicate the line length of all overlapping parts from the user node to the transformer in the substation; the adjacency index between each user node is calculated based on the transformer length and overlapping length; when the adjacency index is less than or equal to a preset similarity threshold, it is determined that the user node does not satisfy the node merging condition; when the adjacency index is greater than the preset similarity threshold, the user node is marked as an intermediate node; voltage information is obtained, the voltage information includes the node voltage value of the intermediate node at time p, and the average voltage value of the substation at time p, where t is an arbitrary constant; the similarity index of the intermediate node is calculated based on the node voltage value and the average voltage value of the substation; when the similarity index is less than or equal to the preset similarity threshold, it is determined that the intermediate node does not satisfy the node merging condition; when the similarity index is greater than the preset similarity threshold, it is determined that the intermediate node satisfies the node merging condition.

[0040] In one embodiment, the line information includes the transformer length and overlap length of each user node. The transformer length represents the line length from the user node to the transformer in the substation. Assuming there are m user nodes in the substation, the line length corresponding to each user node can be calculated as l1, l2, ..., l m In addition, it is also necessary to obtain the overlapping length, which represents the length of all overlapping lines from the user node to the transformer in the substation. Let the number of overlapping lengths be b, and the lengths are l s (s=1,2,...,b). Therefore, the proximity index between each user node can be calculated based on the station length and overlap length, thereby determining the node proximity between nodes. The node proximity index calculation formula can be referred to as:

[0041]

[0042] And obtain the preset similarity threshold, and determine whether the user node is greater than or equal to the similarity threshold one by one. For ease of understanding, the similarity threshold can be set to 95%. Under other implementation conditions, the similarity threshold can be set to another value. This is only an example for ease of understanding and does not limit the solution. In other words, the node adjacency condition can be expressed as:

[0043] index_distance t ≥95% (t=1,2,…,m) (2)

[0044] If it is greater than or equal to the similarity threshold, it can be determined that the user node meets the node adjacency condition and continue with the subsequent judgment. If it does not meet the condition, it is determined that the node does not meet the node merging condition.

[0045] After the user node meets the node adjacency condition, for the sake of easy distinction, the user node that meets the node adjacency condition is called an intermediate node. Continue to determine whether the intermediate node (r nodes are selected from the m nodes in the previous step) meets the voltage similarity condition. Secondly, it is necessary to obtain voltage information, including the node voltage value of the intermediate node at any time. Assume that the node voltage value of the intermediate node at time p is obtained, which is calculated as V t_p (t=1,2,…,r), and at the same time, it is necessary to obtain the average voltage value of the substation in the substation at time p. The average voltage value of the substation is calculated as The similarity index of the intermediate node is calculated based on the node voltage value and the average voltage value of the substation. The calculation process can be referred to:

[0046]

[0047] At the same time, the preset similarity threshold is obtained to determine whether the intermediate node meets the voltage similarity condition. The similarity threshold can be determined based on the maximum and minimum voltages of the substation at time p. The voltage similarity condition can be expressed as:

[0048] index_voltage≤2%(V max_p -V min_p )(t=1,2,...,r) (4)

[0049] In the above formula, V max_p is the maximum voltage of the platform at time p, V min_p is the minimum voltage at the substation at time p. This means that in the voltage similarity condition described in equation (4), the similarity threshold is 2% of the difference between the maximum and minimum substation voltages. The 2% value is just one possible example for ease of understanding and can be modified based on actual needs. There is no limitation on this.

[0050] Therefore, when the similarity index is greater than the preset similarity threshold, the intermediate node is deemed to meet the voltage similarity condition, and since both the node adjacency condition and the voltage similarity condition are met, the intermediate node can be deemed to meet the node merging condition. Conversely, it can be understood that the node merging condition includes both the node adjacency condition and the voltage similarity condition. In a preferred embodiment, the user node needs to first meet the node adjacency condition and then meet the voltage similarity condition before it can be deemed to meet the node merging condition. If any of the conditions is not met, the user node is deemed to have failed to meet the node merging condition.

[0051] Furthermore, user nodes that meet the node merging conditions can be assigned a merge flag; those that do not meet the node merging conditions are assigned an independent flag. This allows user nodes marked with a merge flag in the substation node intermediate model to be merged, while retaining user nodes marked with independent flags. The organized user nodes and substation transformers are then marked as nodes to obtain the substation node model. In other words, each node in the substation node model is actually considered as a separate node.

[0052] Step S120: obtaining the power flow data of the nodes in the substation node model within a predetermined period; bringing the power flow data into the node model to solve the power flow voltage of the node, and summarizing the power flow voltage to construct a voltage sag model.

[0053] In one embodiment, the predetermined time period can specifically be data from a transformer substation during a period of heavy load, such as power flow data during peak electricity consumption. Specifically, this data may include, but is not limited to, phase-by-phase current, voltage, active power, and reactive power parameters at the transformer substation headend (substation supply), as well as current, voltage, active power, and reactive power (three-phase users require phase-by-phase data) at low-voltage users (user terminals). Furthermore, as described above, the transformer substation node model includes merged nodes and independent nodes. The processing methods for these two nodes are also different. For independent nodes, their power flow data retains the data generated by the nodes themselves. For merged nodes, since they are formed by merging multiple user nodes, their power flow data can be processed as follows. First, the merged voltage is the average voltage of all mergeable nodes as the merged node voltage; second, the merged current is the sum of the current values of all mergeable nodes as the merged current; and third, the apparent power is the sum of the apparent powers of all mergeable nodes as the node apparent power. A voltage sag model can then be constructed based on the processed power flow data.

[0054] In one embodiment, step S120: bringing the flow data into the node model to solve the flow voltage of the node, including: obtaining the flow data of the node during the heavy load period of the station transformer, the flow data including the node voltage, node active power and node reactive power; writing the node voltage equation according to the flow data, and using a preset method to solve the node voltage equation to obtain the flow voltage.

[0055] In one embodiment, the first node in the node group is considered as a balance node, and the remaining nodes are considered as PQ nodes. The node voltage equation is written based on the power flow data:

[0056]

[0057] In formula (5), n is the corresponding node number, which is recorded in the substation node model; Y nnis the self-admittance of the corresponding node, Y 1n 、Y n1 is the mutual admittance between nodes 1 and n; is the complex form of the node voltage, is the conjugate form of the node voltage; P n is the node active power; Q n is the node reactive power; j is the imaginary unit in the complex number, j 2 =-1, the above data can be obtained from the node's flow data.

[0058] Furthermore, the forward-backward method can be used to solve the node voltage equation to obtain the iterative solution equation, which is expressed as:

[0059]

[0060] In formula (6), The node voltage values in the kth and k+1th iterations are respectively. The equation is solved iteratively until the voltage calculation results of all nodes in the iterative solution equation converge. The converged calculation results of the nodes are marked as the power flow voltage.

[0061] In one embodiment, due to limitations in measurement device accuracy, number of test calls, and sampling precision, it is currently impossible for household meters to collect accurate real-time data from every load point. Furthermore, the low-voltage distribution network satisfies the R / X integer multiple relationship. Therefore, the calculation of voltage amplitude can approximately ignore the effect of phase angle differences on amplitude in power flow calculations. Therefore, during the iterative calculation process, the node voltage is replaced with a simplified voltage, which only takes the node voltage amplitude as the value, to reduce the computational complexity of the iterative solution. The simplified voltage can be expressed as:

[0062]

[0063] Substitute the simplified voltage in equation (7) into the iterative solution equation of equation (6) to obtain the simplified solution equation, which is expressed as:

[0064]

[0065] The simplified solution equation is solved iteratively until the voltage calculation results for all nodes within the simplified solution equation converge. For the iteration termination condition, an iteration termination threshold ε can be set, specifically 0.01. The specific value range can be set arbitrarily according to requirements. This is only used as an example for explanation, not as a limitation to the solution. If the result obtained after the iteration converges and meets the conditions shown in Equation (9), the calculation result of the last round of iteration can be taken as the power flow voltage of the node.

[0066]

[0067] If the condition shown in formula (9) is not met, continue to iterate according to formula (8).

[0068] Furthermore, after the power flow voltage is obtained, the power flow voltage can be used to calculate |U'1-U1|, |U'2-U2|,..., |U' n -U n |, a voltage sag model is constructed to determine the overall voltage sag in the area before and after load connection. U' is the power flow voltage value at the node after load connection, and U is the power flow voltage value at the node before load connection. The absolute value of the difference between the two reflects the voltage sag. In other words, the voltage sag model is a model that determines the voltage sag value at each node.

[0069] Step S130: Obtain access requirements of business expansion loads, bring the access requirements into the voltage drop model to obtain an access solution, and output it.

[0070] In one embodiment, step S130: bringing the access demand into the voltage drop model to obtain the access plan and output it, including: determining the access mode according to the access demand, the access mode includes a first access mode and a second access mode; when the access mode is the first access mode, obtaining the access load in the access demand, bringing the access load into the voltage drop model, calculating the first voltage drop value generated after the load is connected to all nodes, generating an access plan based on the first voltage drop value and outputting it; when the access mode is the second access mode, obtaining the branch line modification plan and access load in the access demand, modifying the voltage drop model according to the branch line modification plan; bringing the access load into the modified voltage drop model, calculating the second voltage drop value generated after the load is connected to all nodes, generating an access plan based on the second voltage drop value and outputting it.

[0071] In one embodiment, the access demand may include an access mode and an access load. The access load is used to record the power information required for the new load to access the substation; the access mode is used to indicate the method that the node will take to access the substation, specifically including a first access mode and a second access mode. Specifically, the first access mode refers to the business expansion access of new users based on the original grid structure; the second access mode refers to the need to invest in distribution network expansion, ensure the user's business expansion needs by adding new power points, and make an estimated assessment of the selection of power points and the voltage level of the back-end area after the user accesses. Therefore, the two modes require different prediction and evaluation processes, which will be described separately here.

[0072] When the access mode is the first access mode, specifically, the key difference from the second access mode is that in this mode, only the connection method of the existing nodes is used for access, and the connection method between the existing nodes will not be changed. Therefore, the voltage drop model constructed in the previous article will not be changed, and the node admittance matrix in formula (5) remains unchanged. Assuming that there are y types of access power point schemes that can be selected, for y types of schemes, the P and Q of the node corresponding to the power access point in formula (5) are modified to characterize the load situation of the node after access. Assuming that the access power point corresponds to node i (taking a single user access as an example, multiple users can be compared), the variable active power and variable reactive power in the access load are obtained, which are respectively calculated as ΔP i and ΔQ i , and modify the P in the i-th row on the right side of formula (5) i , Q i They are (P i +ΔP i )、(Q i +ΔQ i ), as shown in formula (10):

[0073]

[0074] Then, forward and backward calculations are performed according to formula (8) until the condition of formula (9) is met. Thus, the first voltage drop value is obtained, which indicates the voltage change that will occur at each node in the substation node model after the new load is included, thus completing the prediction of y scenarios.

[0075] Furthermore, it can be seen that after predicting all possible access options, the optimal solution can be selected, that is, the one with the least impact on the substation voltage, as the optimal solution output, thereby guiding on-site personnel to complete load access. Specifically, for y solutions, the voltage results obtained after the business expansion access are y, satisfying the conditions of formula (11), that is, the voltage level in the substation after the business expansion meets the power supply business rules, that is, the first voltage drops to the required fluctuation range of (90% to 107%) of the rated voltage:

[0076]

[0077] Taking into account the subsequent business expansion needs, the business expansion plan with the smallest average voltage drop is selected as the optimal business expansion plan and output.

[0078] When the access mode is the second access mode, the existing voltage drop model needs to be changed. Similarly, assuming that there are y options for expanding the power supply point on site, the investment for each of the y options is Sd (d = 1, 2, ..., y). At the same time, according to the branch line modification plan in the access requirements, assuming that a new line is added to the original grid, the branch f corresponding to the new line (the corresponding self-admittance is Y ff , and the original network nodes are Y 1f , Y 2f ,...,Y n+1,f ), the access power point corresponds to the newly added voltage node f, (taking the addition of one branch to the grid and the access of a single user as an example, multiple branches and multiple users can be analogized) to modify the voltage drop model. Specifically, the original formula (5) can be modified to the current formula (12):

[0079]

[0080] Then, perform forward and backward calculations according to formula (8) until the condition of formula (9) is met, thereby obtaining the second voltage drop value. The second voltage drop value indicates the maximum number of voltage drops that will be generated when the new branch is connected to the load in the second access mode. For y solutions, the voltage results after the business expansion access are y, and the condition of formula (11) must also be met. The goal is to minimize the power supply cost of the expanded power point, as shown in formula (13):

[0081]

[0082] Therefore, based on the predicted y options, the business expansion option with the smallest average voltage drop and the smallest investment cost determined according to the access demand is selected as the optimal business expansion option and output.

[0083] Therefore, the present application can use the low-voltage substation topology data to construct a substation solution model before the load is connected, and solve the current voltage to obtain a voltage drop model that reflects the voltage changes in the back-end area after the load is connected. Then, using the demand of the load that needs to be connected, the voltage changes in the back-end area of the load access node are predicted to obtain the access plan and output it, which solves the defect in the existing technology that there is no current calculation to solve the optimal access plan for low-voltage business expansion. At the same time, the characteristics of the low-voltage distribution network are also utilized in the calculation process to simplify the iteration and greatly reduce the amount of calculation.

[0084] Figure 2The figure shows the relationship between the internal functional modules of a low-voltage business expansion access device in one embodiment. The low-voltage business expansion access device 20 includes: a modeling module 21, a calculation module 22, and a simulation module 23. The modeling module 21 is used to obtain low-voltage substation topology map data to construct a substation node model, which includes multiple nodes. The calculation module 22 is used to obtain the flow data of the nodes in the substation node model within a predetermined time period; bring the flow data into the node model to solve the flow voltage of the node, and summarize the flow voltage to construct a voltage drop model. The simulation module 23 is used to obtain the access requirements of the business expansion load, bring the access requirements into the voltage drop model to obtain the access plan, and output it.

[0085] Figure 3 FIG1 shows an internal structure diagram of a computer device in an embodiment. The computer device can be a terminal or a server. Figure 3 As shown, the computer device includes a processor, a memory, and a network interface connected via a system bus. The memory includes a non-volatile storage medium and an internal memory. The non-volatile storage medium of the computer device stores an operating system and may also store a computer program. When the computer program is executed by the processor, the processor can implement the low-voltage business expansion access method. The internal memory may also store a computer program. When the computer program is executed by the processor, the processor can implement the low-voltage business expansion access method. Those skilled in the art will understand that Figure 3 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than shown in the figure, or combine certain components, or have a different component arrangement.

[0086] In one embodiment, the present application further proposes a computer-readable storage medium storing a computer program. When the computer program is executed by a processor, the processor executes the steps of the aforementioned method.

[0087] Those skilled in the art will appreciate that all or part of the processes in the above-mentioned embodiments can be implemented by instructing the relevant hardware through a computer program. The program can be stored in a non-volatile computer-readable storage medium. When the program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0088] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0089] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A low-voltage business expansion access method, characterized in that: The steps include: Acquire low-voltage substation topology data to construct a substation node model, wherein the substation node model includes a plurality of nodes; Obtaining the flow data of the node in the substation node model within a predetermined time period; Bringing the power flow data into the node model to solve the power flow voltage of the node, and summarizing the power flow voltage to construct a voltage drop model; Obtaining access requirements of business expansion loads, applying the access requirements to the voltage drop model to obtain an access solution, and outputting the solution; The step of constructing the substation node model includes: Constructing an area node intermediate model according to the low-voltage area topology data, wherein the area node intermediate model includes an area transformer and multiple user nodes; Acquire line length information and voltage information of the user node according to the low-voltage area topology data, and calculate one by one whether a node merging condition is satisfied between a plurality of the user nodes according to the line length information and the voltage information; If the node merging condition is satisfied between the plurality of user nodes, a merge mark is assigned to the user nodes satisfying the node merging condition; if the node merging condition is not satisfied between the plurality of user nodes, an independent mark is assigned to the user nodes not satisfying the node merging condition; The user nodes in the substation node intermediate model are merged according to the merge mark, and the user nodes with the independent mark are retained; the sorted user nodes and the substation transformers are marked as the nodes to obtain the substation node model.

2. The low voltage business expansion access method according to claim 1, wherein: The calculating, one by one according to the line length information and the voltage information, whether a node merging condition is satisfied between the plurality of user nodes includes: The line length information includes the station transformer length and overlapping length of each user node, wherein the station transformer length is used to indicate the line length from the user node to the station transformer, and the overlapping length is used to indicate the length of all overlapping parts of the lines from the user node to the station transformer; Calculate the proximity index between each of the user nodes according to the station variation length and the overlap length; When the proximity index is less than or equal to a preset proximity threshold, determining that the user node does not meet the node merging condition; When the proximity index is greater than a preset proximity threshold, marking the user node as an intermediate node; obtaining the voltage information, the voltage information including the node voltage value of the intermediate node at time p and the average voltage value of the substation at time p, where p is an arbitrary constant; Calculating a similarity index of the intermediate node according to the node voltage value and the average voltage value of the substation; When the similarity index is less than or equal to a preset similarity threshold, determining that the intermediate node does not meet the node merging condition; When the similarity index is greater than a preset similarity threshold, it is determined that the intermediate node meets the node merging condition.

3. The low voltage business expansion access method according to claim 1, wherein: Bringing the power flow data into the node model to solve the power flow voltage of the node includes: Acquire the power flow data of the node during a period of heavy load, the power flow data including node voltage, node active power and node reactive power; A node voltage equation is written according to the power flow data, and the node voltage equation is solved using a preset method to obtain the power flow voltage.

4. The low voltage business expansion access method according to claim 3, wherein: The step of writing a node voltage equation according to the power flow data and solving the node voltage equation using a preset method to obtain the power flow voltage includes: The first node in the node is regarded as a balance node, and the rest are regarded as PQ nodes. The node voltage equation is written according to the power flow data: ； is the self-admittance of the corresponding node, 、 is the mutual admittance between nodes 1 and n; is the node voltage; is the active power of the node; is the reactive power of the node; j is the imaginary unit in the complex number, j 2 =-1; The node voltage equation is solved by using the forward-backward method to obtain an iterative solution equation, which is expressed as: ； The iterative solution equation is iteratively calculated until voltage calculation results of all nodes in the iterative solution equation converge, and the converged calculation results of the nodes are marked as the power flow voltage.

5. The low voltage business expansion access method according to claim 4, characterized in that: The iterative calculation of the node voltage equation until voltage calculation results of all nodes in the node voltage equation converge, includes: Ignoring the influence of the phase angle difference within the node voltage on the amplitude, the node voltage is replaced by a simplified voltage. The simplified voltage only takes the amplitude of the node voltage. The simplified voltage is expressed as: ； Substitute the simplified voltage into the iterative solution equation to obtain a simplified solution equation, which is expressed as: ； The simplified solution equation is solved iteratively until voltage calculation results of all nodes in the simplified solution equation converge.

6. The low voltage business expansion access method according to claim 1, wherein: The step of bringing the access requirement into the voltage drop model to obtain and output an access solution includes: An access mode is determined based on the access demand, and the access mode includes a first access mode and a second access mode. The first access mode refers to expanding the access of new users based on the existing network structure; the second access mode refers to the need to invest in distribution network expansion and meet the user's business expansion needs by adding new power points. When the access mode is the first access mode, obtaining an access load in the access requirement, substituting the access load into the voltage drop model, calculating a first voltage drop value generated after the load is connected to all the nodes, and generating and outputting the access plan based on the first voltage drop value; When the access mode is the second access mode, obtain the branch line modification plan and the access load in the access requirement, and modify the voltage drop model according to the branch line modification plan; bring the access load into the modified voltage drop model, calculate the second voltage drop value generated after the load is connected to all the nodes, and generate and output the access plan according to the second voltage drop value.

7. A low-voltage business expansion access device, characterized in that: include: A modeling module is used to obtain low-voltage substation topology data to construct a substation node model, wherein the substation node model includes multiple nodes; A calculation module, used for obtaining the flow data of the nodes in the substation node model within a predetermined time period; Bringing the power flow data into the node model to solve the power flow voltage of the node, and summarizing the power flow voltage to construct a voltage drop model; A simulation module, configured to obtain access requirements of business expansion loads, and to input the access requirements into the voltage drop model to obtain and output an access solution; The modeling module is further used to construct an intermediate model of the substation node according to the low-voltage substation topology map data, wherein the intermediate model of the substation node includes a substation transformer and multiple user nodes; Acquire line length information and voltage information of the user node according to the low-voltage area topology data, and calculate one by one whether a node merging condition is satisfied between a plurality of the user nodes according to the line length information and the voltage information; If a node merging condition is satisfied between multiple user nodes, a merge mark is assigned to the user nodes satisfying the node merging condition; If the node merging condition is not satisfied between the plurality of user nodes, then the user nodes that do not satisfy the node merging condition are assigned independent marks; Merging the user nodes in the station node intermediate model according to the merge mark, and retaining the user nodes with the independent mark; The user nodes and the substation transformers that have been sorted are marked as nodes to obtain the substation node model.

8. A computer device, characterized in that: including processor and memory; The processor is configured to execute the computer program stored in the memory to implement the method according to any one of claims 1 to 6.

9. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the method according to any one of claims 1 to 6 is implemented.

Images