Methods, devices, equipment and media for determining the closed-loop current of active distribution networks

Abstract

This invention discloses a method, apparatus, electronic device, and storage medium for determining the closed-loop current of an active distribution network. Its features include: if a closed-loop operation is detected in the active distribution network, determining the switching position of the operated closed-loop switch, and determining the target electrical island corresponding to the active distribution network based on the switch position; for each target electrical island, performing power flow calculations based on the Newton-Raphson method to obtain a first Jacobian matrix corresponding to the power flow balance information of the target electrical island before the closed-loop switch is closed, and a second Jacobian matrix corresponding to the power flow change information of the target electrical island after the closed-loop switch is closed; constructing a third Jacobian matrix of the active distribution network based on the first and second Jacobian matrices corresponding to each target electrical island, and calculating the closed-loop current of the active distribution network based on the third Jacobian matrix. This achieves rapid scanning and calculation of power flow in a large-scale power grid with multiple closed-loop switches.

Description

Technical Field

[0001] This invention relates to the field of power system technology, and in particular to a method, apparatus, equipment and medium for determining the closed-loop current of an active distribution network. Background Technology

[0002] Currently, China's power distribution network follows the principle of "closed-loop design, open-loop operation." When a fault occurs in the distribution network or maintenance is required, power is typically cut off first, then the load is transferred, and power is restored only after the fault is cleared or maintenance is completed. Clearly, this operating mode increases the number of power outages and prolongs their duration, leading to reduced power supply reliability. To improve power supply reliability, power companies use closed-loop operation of the distribution network to achieve uninterrupted load transfer.

[0003] The loop closure operation in a distribution network alters the power flow distribution, causing changes in the steady-state current of each branch. This alteration can lead to overload problems on certain lines, ultimately causing relay protection devices to trip. This is a major cause of loop closure operation failures. Therefore, before performing a loop closure operation, dispatchers can use computer programs to quickly calculate the current after loop closure, providing a useful reference. However, in actual power grid operation, due to the large number of loop closure switches to consider, the power flow scan after the loop closure operation requires calculations on a large number of closed switches, resulting in excessively long calculation times and making it difficult to apply in practice. Summary of the Invention

[0004] This invention provides a method, apparatus, equipment, and medium for determining the closed-loop current in an active power distribution network, in order to solve the problem of excessively long calculation time for closed-loop power flow and achieve rapid calculation of closed-loop power flow.

[0005] According to one aspect of the present invention, a method for determining the closed-loop current of an active distribution network is provided, comprising:

[0006] If a loop-closing operation is detected for an active distribution network, the switch position of the operated loop-closing switch is determined, and the target electrical island corresponding to the active distribution network is determined based on the switch position. The target electrical island includes the main grid electrical island, the left distribution network electrical island, and the right distribution network electrical island.

[0007] For each target electrical island, power flow calculation is performed on the target electrical island based on the Newton-Raphson method to obtain a first Jacobian matrix corresponding to the power flow balance information of the target electrical island before the closing of the loop switch and a second Jacobian matrix corresponding to the power flow change information of the target electrical island after the closing of the loop switch.

[0008] The third Jacobian matrix of the active distribution network is constructed based on the first Jacobian matrix and the second Jacobian matrix corresponding to each of the target electrical islands, and the loop current of the active distribution network is calculated based on the third Jacobian matrix.

[0009] According to another aspect of the present invention, a device for determining the closed-loop current of an active power distribution network is provided, comprising:

[0010] The loop-closing detection module is used to determine the switch position of the operated loop-closing switch if a loop-closing operation for an active distribution network is detected, and to determine the target electrical island corresponding to the active distribution network based on the switch position. The target electrical island includes the main grid electrical island, the left distribution network electrical island, and the right distribution network electrical island.

[0011] The power flow calculation module is used to perform power flow calculation on each target electrical island based on the Newton-Raphson method to obtain a first Jacobian matrix corresponding to the power flow balance information of the target electrical island before the closing of the loop switch and a second Jacobian matrix corresponding to the power flow change information of the target electrical island after the closing of the loop switch.

[0012] The loop current calculation module is used to construct the third Jacobian matrix of the active distribution network based on the first Jacobian matrix and the second Jacobian matrix corresponding to each of the target electrical islands, and to calculate the loop current of the active distribution network based on the third Jacobian matrix.

[0013] According to another aspect of the present invention, an electronic device is provided, the electronic device comprising:

[0014] At least one processor; and

[0015] A memory communicatively connected to the at least one processor; wherein,

[0016] The memory stores a computer program that can be executed by the at least one processor, which enables the at least one processor to perform the loop current method for active distribution networks according to any embodiment of the present invention.

[0017] According to another aspect of the present invention, a computer-readable storage medium is provided, the computer-readable storage medium storing computer instructions for causing a processor to execute and implement the loop current method for an active power distribution network according to any embodiment of the present invention.

[0018] The technical solution of this invention involves determining the switching position of the closed loop switch if a closed loop operation is detected in an active distribution network, and identifying the target electrical island corresponding to the active distribution network based on the switch position. The target electrical island includes a main grid electrical island, a left-side distribution network electrical island, and a right-side distribution network electrical island. For each electrical island, node values ​​are obtained. For each target electrical island, power flow calculation is performed based on the Newton-Raphson method to obtain a first Jacobian matrix corresponding to the power flow balance information of the target electrical island before the closed loop switch is closed, and a second Jacobian matrix corresponding to the power flow change information of the target electrical island after the closed loop switch is closed. By performing power flow calculation separately for each electrical island, the computational load in power flow calculation can be effectively reduced, and the calculation speed can be improved. Power flow calculation is performed again after the closed loop switch is closed, improving the accuracy of the closed loop switch change calculation. A third Jacobian matrix of the active distribution network is constructed based on the first and second Jacobian matrices corresponding to each target electrical island, and the closed loop current of the active distribution network is calculated based on the third Jacobian matrix. By calculating the power flow of the three electrical islands and splicing the Jacobian matrix, the closed-loop current of the active distribution network is calculated. This solves the problem that calculating the closed-loop power flow of a large number of closed-loop switches would lead to excessively long power flow scanning calculation time, and enables fast calculation of closed-loop power flow.

[0019] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a flowchart of a method for determining the loop current of an active power distribution network according to an embodiment of the present invention;

[0022] Figure 2 This is an example diagram of a target electrical island provided in an embodiment of the present invention;

[0023] Figure 3 This is a flowchart of another method for determining the loop current of an active distribution network provided by an embodiment of the present invention;

[0024] Figure 4 This is a flowchart of another method for determining the loop current of an active distribution network provided by an embodiment of the present invention;

[0025] Figure 5 This is a schematic diagram of the structure of a device for determining the closed-loop current of an active power distribution network provided in an embodiment of the present invention;

[0026] Figure 6 This is a schematic diagram of the structure of an electronic device that implements the method for determining the closed-loop current of an active power distribution network according to an embodiment of the present invention. Detailed Implementation

[0027] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0028] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0029] Figure 1 This invention provides a flowchart for determining the closed-loop current of an active distribution network, as described in Embodiment 1. This embodiment is applicable to the determination of the closed-loop current of a large-scale active distribution network through power flow calculation. The method can be executed by a device for determining the closed-loop current of an active distribution network, which can be implemented in hardware and / or software and can be configured in an electronic device. Figure 1 As shown, the method includes:

[0030] S110. If a loop-closing operation is detected for an active distribution network, determine the switch position of the operated loop-closing switch, and determine the target electrical island corresponding to the active distribution network based on the switch position.

[0031] The target electrical island includes the main grid electrical island, the left distribution network electrical island, and the right distribution network electrical island.

[0032] In electrical operations, loop closing can refer to the operation of closing a network consisting of lines, transformers, or circuit breakers in series during power system operation. Typically, it can be the operation of closing a loop closing switch. It is understood that one or more loop closing switches can exist in an active distribution network.

[0033] Specifically, in an active distribution network, a loop-closing operation targeting the active distribution network is detected, the switching position of the operated loop-closing switch is determined, and the target electrical island corresponding to the active distribution network is determined based on the switching position.

[0034] Figure 2 This is an example diagram of a target electrical island provided in an embodiment of the present invention. Figure 2 As shown: The target electrical island includes the upper main grid electrical island, the left distribution network electrical island, and the right distribution network electrical island. The loop-closing switch is located between the left and right distribution network electrical islands; the main grid electrical island and the left distribution network electrical island also include boundary nodes M and C; the left and right distribution network electrical islands also include boundary nodes A and B; and the main grid electrical island and the right distribution network electrical island also include boundary nodes N and D.

[0035] Optionally, in an active distribution network, before the loop closing operation, network parameters related to the loop closing operation are collected, such as the impedance Z between two arbitrary nodes. ij The admittance Y of the node to ground i Then, the nodal admittance matrix of the relevant network can be obtained. Furthermore, the self-admittance Y of the nodes can be derived. ij =G ij +jB ij Mutual admittance of nodes Y ij =G ij +jB ij Initial voltage V at the node i Node injection power P i and Q i Then, power flow equilibrium equations are constructed based on the collected network parameters.

[0036] S120. For each target electrical island, power flow calculation is performed on the target electrical island based on the Newton-Raphson method to obtain a first Jacobian matrix corresponding to the power flow balance information of the target electrical island before the closing of the loop switch and a second Jacobian matrix corresponding to the power flow change information of the target electrical island after the closing of the loop switch.

[0037] Considering that in the power flow calculations of the left and right distribution network electrical islands before loop closure, the nodes connected to the main grid electrical island are considered as slack nodes (power sources). However, after loop closure, the two boundary nodes of the left and right distribution network electrical islands are no longer considered as slack nodes, but as PQ nodes in the new ring network. Therefore, we can determine the target electrical island corresponding to the loop closure operation, and for each target electrical island, perform power flow calculations based on the Newton-Raphson method to obtain the first Jacobian matrix corresponding to the power flow balance information of each target electrical island before the loop closure. Then, we can calculate the second Jacobian matrix corresponding to the power flow change information of each target electrical island after the loop closure based on the Newton-Raphson method.

[0038] S130. Construct the third Jacobian matrix of the active distribution network based on the first Jacobian matrix and the second Jacobian matrix corresponding to each of the target electrical islands, and calculate the loop current of the active distribution network based on the third Jacobian matrix.

[0039] Specifically, the first Jacobian matrix corresponding to the power flow balance information before the closing of the loop switch for each target electrical island and the second Jacobian matrix corresponding to the power flow change information after the closing of the loop switch for each target electrical island are spliced ​​together to obtain the third Jacobian matrix of the active distribution network. Then, the loop current of the active distribution network is calculated through the third Jacobian matrix.

[0040] The technical solution of this invention involves determining the switching position of the closed loop switch if a closed loop operation is detected in an active distribution network, and identifying the target electrical island corresponding to the active distribution network based on the switch position. The target electrical island includes a main grid electrical island, a left-side distribution network electrical island, and a right-side distribution network electrical island. For each electrical island, node values ​​are obtained. For each target electrical island, power flow calculation is performed based on the Newton-Raphson method to obtain a first Jacobian matrix corresponding to the power flow balance information of the target electrical island before the closed loop switch is closed, and a second Jacobian matrix corresponding to the power flow change information of the target electrical island after the closed loop switch is closed. By performing power flow calculation separately for each electrical island, the computational load in power flow calculation can be effectively reduced, and the calculation speed can be improved. Power flow calculation is performed again after the closed loop switch is closed, improving the accuracy of the closed loop switch change calculation. A third Jacobian matrix of the active distribution network is constructed based on the first and second Jacobian matrices corresponding to each target electrical island, and the closed loop current of the active distribution network is calculated based on the third Jacobian matrix. By calculating the power flow of the three electrical islands and splicing the Jacobian matrix, the closed-loop current of the active distribution network is calculated. This solves the problem that calculating the closed-loop power flow of a large number of closed-loop switches would lead to excessively long power flow scanning calculation time, and enables fast calculation of closed-loop power flow.

[0041] Figure 3 This invention provides another flowchart for determining the loop current in an active distribution network. This embodiment specifically illustrates the calculation of the first and second Jacobian matrices in a large active distribution network power flow, as follows: Figure 3 As shown, the method includes:

[0042] S210. If a loop-closing operation is detected for an active distribution network, determine the switch position of the operated loop-closing switch, and determine the target electrical island corresponding to the active distribution network based on the switch position.

[0043] S220. Determine at least two power flow calculation nodes of the target electrical island.

[0044] The power flow calculation node can be understood as a node in an active distribution network used for power flow calculation. Each target electrical island may include multiple power flow calculation nodes. In this embodiment of the invention, the power flow calculation node includes at least the boundary nodes of the target electrical island. In other words, the power flow calculation node includes the boundary nodes of the target electrical island, and may also include other nodes besides the boundary nodes.

[0045] Continue Figure 2 Between the main grid electrical island and the left distribution network electrical island, there may be power flow calculation nodes M and C; between the left distribution network electrical island and the right distribution network electrical island, there may be power flow calculation nodes A and B; between the main grid electrical island and the right distribution network electrical island, there may be power flow calculation nodes N and D. Power flow calculation nodes M and N can serve as boundary nodes of the main grid electrical island, power flow calculation nodes A and C can serve as boundary nodes of the left distribution network electrical island, and power flow calculation nodes B and D can serve as boundary nodes of the right distribution network electrical island.

[0046] Specifically, when performing power flow calculations, the boundary nodes located at the connection points of each target electrical island can be used as two power flow calculation nodes for the target electrical island.

[0047] S230. Construct the first power flow balance equation for each power flow calculation node before the loop switch is closed to obtain a power flow equation set. Use the Newton-Raphson method to perform power flow calculation on the power flow balance equation set to obtain the first Jacobian matrix.

[0048] Optionally, for each target electrical island, a first power flow balance equation is constructed for each power flow calculation node before the loop switch is closed. Then, a power flow equation set is formed by two or more first power flow balance equations. Further, the Newton-Raphson method is used to calculate the power flow balance equation set for each node corresponding to each target electrical island, obtaining the Jacobian matrix corresponding to each target electrical island.

[0049] For example, the first power flow equilibrium equation constructed at node i is shown in the power flow equation set as shown in formula (1):

[0050]

[0051] Where, ΔP i and ΔQ i It is the deviation of the injected active and reactive power at node i; P i s and It refers to the injected active and reactive power at node i; V i and V j These are the voltage magnitudes at nodes i and j, respectively; G ij Y is the mutual admittance between node i and node j. ij The real part, B ij Y is the imaginary part of the mutual admittance between node i and node j. ij =G ij +jB ij ;δ ij =δ i -δ j It is the phase angle difference between the node voltages of node i and node j.

[0052] Furthermore, the Newton-Raphson method was used to perform power flow calculations on the power flow equilibrium equations, and the corrected equation formula (2) was obtained:

[0053]

[0054] In formula (2):

[0055] Then through

[0056] Convert formula (2) into matrix form, as shown in formula (3):

[0057]

[0058] remember

[0059] Then, formula (3) is transformed into formula (4), which is shown below:

[0060] ΔS=JΔx (4)

[0061] Where ΔS is the imbalance quantity; J is the Jacobian matrix; and Δx is the state variable.

[0062] For ease of description, in this embodiment of the invention, the Jacobian matrix corresponding to the main grid electrical island is identified by H, the Jacobian matrix corresponding to the left distribution network electrical island is identified by L, and the Jacobian matrix corresponding to the right distribution network electrical island is identified by R. The process of solving the Jacobian matrix can refer to the solution process of J in equations (1) to (4) above.

[0063] S240. Determine the power flow change information of the boundary nodes of the target electrical island before and after the loop switch is closed, and construct a second Jacobian matrix based on the power flow change information.

[0064] Among them, the power flow change information refers to the changes in the power flow balance information before the closing of the loop switch at the boundary node and the power flow balance information after the closing of the loop switch. That is, the information on the changes in the power flow distribution at the boundary node before and after the closing of the loop switch.

[0065] Specifically, after the boundary node loop is closed, the power flow balance information before and after the loop is closed is used to determine the power flow change information of the boundary node of the target electrical island before and after the loop is closed, and a second Jacobian matrix is ​​constructed based on the power flow change information.

[0066] Optionally, determining the power flow change information of the boundary nodes of the target electrical island before and after the loop switch is closed, and constructing a second Jacobian matrix based on the power flow change information, includes: constructing voltage amplitude constraint equations and voltage phase angle constraint equations for each boundary node of the target electrical island after the loop switch is closed, as well as power flow change equations for each boundary node; and constructing a second Jacobian matrix based on the voltage amplitude constraint equations, the voltage phase angle constraint equations, and the power flow change equations.

[0067] Since the voltage amplitude and phase angle at the connection points between the main grid electrical island and the distribution grid electrical island are equal, six constraint equations were extended based on the original power flow balance equations of the target electrical island, and these equations were continued to be used. Figure 2 After the loop switch is closed, the voltage magnitude and phase angle constraint equations for boundary nodes M and C between the main grid electrical island and the left distribution network electrical island are as shown in equations (5) and (6):

[0068] Δδ MC =δ M -δ C (5)

[0069] ΔVMC =V M -V C (6)

[0070] Where, Δδ MC Let ΔV be the unbalanced phase angle of the node voltages at boundary nodes M and C. MC This represents the imbalance in the voltage magnitudes of boundary nodes M and C.

[0071] Similarly, the voltage magnitude and phase angle constraint equations for boundary nodes N and D between the main grid electrical island and the right-side distribution network electrical island are shown in equations (7) and (8):

[0072] Δδ ND =δ N -δ D (7)

[0073] ΔV ND =V N -V D (8)

[0074] Where, Δδ ND Let ΔV be the unbalanced phase angle of the node voltages at boundary nodes N and D. ND This represents the imbalance in the node voltage magnitudes of boundary nodes N and D.

[0075] Similarly, the voltage magnitude and phase angle constraint equations for boundary nodes A and B between the left and right electrical islands of the distribution network are shown in equations (9) and (10):

[0076] Δδ AB =δ A -δ B (9)

[0077] ΔV AB =V A -V B (10)

[0078] Where, Δδ AB Let ΔV be the unbalanced phase angle of the node voltages at boundary node A and boundary node B. AB This represents the imbalance in the voltage magnitudes of boundary node A and boundary node B.

[0079] Furthermore, six state variables were added to the power flow balance equations, namely ΔP at the connection between the left-side distribution network electrical island and the main network electrical island. MC and ΔQ MC(Taking the flow from boundary node M to boundary node C as the positive direction), ΔP at the connection between the right-side distribution network electrical island and the main network electrical island. ND and ΔQ ND (Taking the flow from boundary node N to boundary node D as the positive direction), ΔP at the connection between the left and right electrical islands of the distribution network. AB and ΔQ AB (Taking the flow from boundary node A to boundary node B as the positive direction). The power flow equations for each of the boundary nodes change after the loop is closed as follows:

[0080] The power flow equations at boundary node A and boundary node B are shown in equations (11) to (14), respectively:

[0081]

[0082]

[0083]

[0084]

[0085] Among them, P AB and Q AB These represent the active power and reactive power flowing from boundary node A to boundary node B, respectively.

[0086] The power flow equations at boundary node M and boundary node C are shown in equations (15) to (18), respectively:

[0087]

[0088]

[0089]

[0090]

[0091] Among them, P MC and Q MC These represent the active power and reactive power flowing from boundary node M to boundary node C, respectively.

[0092] The power flow equations at boundary node N and boundary node D are shown in equations (18) to (22), respectively:

[0093]

[0094]

[0095]

[0096]

[0097] Among them, P ND and Q ND These represent the active power and reactive power flowing from boundary node N to boundary node D, respectively.

[0098] Specifically, the voltage magnitude constraint equation, voltage phase angle constraint equation, and power flow change equation of each boundary node of the target electrical island after the loop switch is closed are constructed respectively. Based on the voltage magnitude constraint equation, voltage phase angle constraint equation, and power flow change equation of each boundary node after the loop switch is closed, the second Jacobian matrix is ​​constructed.

[0099] Optionally, constructing the second Jacobian matrix based on the voltage magnitude constraint equation, the voltage phase angle constraint equation, and the power flow variation equation includes: taking partial derivatives of the voltage magnitude constraint equation and the voltage phase angle constraint equation with respect to the voltage magnitude and voltage phase angle, respectively, to obtain a first identity matrix corresponding to the target electrical island; determining the power flow variation in the power flow variation equation based on the first power flow balance equation corresponding to the boundary node; taking partial derivatives of the power flow variation equation with respect to the power flow variation to obtain a second identity matrix corresponding to the target electrical island; and determining the second Jacobian matrix based on the first identity matrix and the second identity matrix, respectively.

[0100] Specifically, by taking the partial derivatives of the voltage amplitude constraint equation and the voltage phase angle constraint equation with respect to the voltage amplitude and voltage phase angle, respectively, a first identity matrix corresponding to the target electrical island is obtained. Further, the first identity matrix can be subjected to matrix transformations to obtain a second Jacobian matrix, wherein the matrix transformations include at least one of matrix transpose, negation, and padding of matrix elements with zeros.

[0101] For example, such as Figure 2 Taking boundary node M and boundary node C as examples: According to formulas (5) and (6), the voltage amplitude ΔV between boundary node M and boundary node C between the main grid electrical island and the left distribution network electrical island is known. MC and voltage phase angle Δδ MC By taking the partial derivatives from formulas (1) to (4), the first identity matrix is ​​finally obtained as shown below:

[0102] For example, the first identity matrices of boundary nodes M, N, A, B, C, and D can be respectively and

[0103] Furthermore, based on the first tidal current balance equation corresponding to the boundary node, the tidal current change amount in the tidal current change equation is determined. The partial derivative of the tidal current change equation with respect to the tidal current change amount is then taken to obtain the second identity matrix corresponding to the target electrical island. Further, the second identity matrix can be subjected to matrix transformation processing to obtain the second Jacobian matrix, wherein the matrix transformation processing includes at least one of matrix transpose, taking a negative number, and padding matrix elements with zeros.

[0104] Optional, such as Figure 2 Taking the middle boundary node M and boundary node C as examples, the power flow change of the power flow equations of boundary nodes M and C is determined as shown in formulas (15) to (18), and then the partial derivatives are obtained by formulas (1) to (4) to obtain the second identity matrix.

[0105] For example, the second Jacobian matrix corresponding to boundary nodes M, N, A, B, C, and D may each further include -E. M -E N -E A -E B -E C and -E D .

[0106] In this embodiment of the invention, the second Jacobian matrix may include a transformation matrix of the first identity matrix and the second identity matrix.

[0107] S250. Construct the third Jacobian matrix of the active distribution network based on the first Jacobian matrix and the second Jacobian matrix corresponding to each of the target electrical islands, and calculate the loop current of the active distribution network based on the third Jacobian matrix.

[0108] The technical solution of this invention, if a loop-closing operation is detected in an active distribution network, determines the switching position of the operated loop-closing switch, and determines the target electrical island corresponding to the active distribution network based on the switch position. The target electrical island includes a main grid electrical island, a left-side distribution network electrical island, and a right-side distribution network electrical island. Based on the boundary nodes between each electrical island, the network parameters of the boundary nodes are obtained. For each target electrical island, power flow calculation is performed based on the Newton-Raphson method to obtain a first Jacobian matrix corresponding to the power flow balance information of the target electrical island before the loop-closing switch is closed. By performing power flow calculation separately for each electrical island, power flow can be effectively reduced. The calculations are streamlined to reduce computational load and increase speed. Power flow calculations are performed again upon loop closure to improve accuracy. Partial derivatives of the voltage amplitude constraint equation, voltage phase angle constraint equation, and power flow change equations at boundary nodes are used to derive the first and second identity matrices. The second Jacobian matrix is ​​then determined based on these matrices. By modifying and expanding the power flow equations, errors caused by loop closure operations in the active distribution network's power flow equations are reduced. A third Jacobian matrix for the active distribution network is constructed based on the first and second Jacobian matrices corresponding to each target electrical island. The loop current of the active distribution network is then calculated using this third Jacobian matrix. By calculating the power flow of the three electrical islands and concatenating the Jacobian matrices to calculate the loop current of the active distribution network, the problem of excessively long power flow scanning calculations caused by performing loop power flow calculations on a large number of loop closure switches is solved, enabling rapid calculation of loop power flow.

[0109] Figure 4 This invention provides another flowchart for determining the loop current in an active distribution network. This embodiment specifically illustrates the calculation of the first and second Jacobian matrices in a large active distribution network power flow, as follows: Figure 4 As shown, the method includes:

[0110] S310. If a loop-closing operation is detected for an active distribution network, determine the switch position of the operated loop-closing switch, and determine the target electrical island corresponding to the active distribution network based on the switch position.

[0111] S320. For each target electrical island, power flow calculation is performed on the target electrical island based on the Newton-Raphson method to obtain a first Jacobian matrix corresponding to the power flow balance information of the target electrical island before the closing of the loop switch and a second Jacobian matrix corresponding to the power flow change information of the target electrical island after the closing of the loop switch.

[0112] S330. The first Jacobian matrix and the second Jacobian matrix corresponding to each of the target electrical islands are concatenated, and the concatenated matrix is ​​sparsified to obtain the third Jacobian matrix of the active power distribution network, wherein the first Jacobian matrix of the main grid electrical island is located at the upper left corner of the third Jacobian matrix.

[0113] Optionally, after concatenating the first and second Jacobian matrices and sparsifying the concatenated matrix, the resulting third Jacobian matrix contains singular matrices L and R in the first Jacobian matrix, and non-singular matrices H in the Jacobian matrix of the main grid electrical island. Furthermore, in the third Jacobian matrix, the Jacobian matrix H of the main grid electrical island is placed in the upper left corner for elimination. During the iterative calculation, the Jacobian matrices L and R of the left and right distribution network electrical islands are continuously modified.

[0114] S340. Determine the active power deviation and reactive power deviation at the connection points of the left distribution network electrical island and the main network electrical island, the right distribution network electrical island and the main network electrical island, and the left distribution network electrical island and the right distribution network electrical island.

[0115] Specifically, the active power deviation and reactive power deviation at the connection points between the left distribution network electrical island and the main network electrical island, the right distribution network electrical island and the main network electrical island, and the left distribution network electrical island and the right distribution network electrical island are determined respectively.

[0116] like Figure 2 As shown, the active power deviation and reactive power deviation at the connection between the distribution network electrical island and the main network electrical island on the left are respectively: ΔP MC ΔQ MC The active power deviation and reactive power deviation at the connection point between the right-side distribution network electrical island and the main network electrical island are respectively: ΔP ND and ΔQ ND The active power deviation and reactive power deviation at the connection points between the left and right electrical islands of the distribution network are respectively: ΔP AB ΔQ AB .

[0117] S350. Construct the power flow correction equation of the active distribution network based on the third Jacobian matrix, the active power deviation, and the reactive power deviation, and calculate the closed loop current of the active distribution network based on the power flow correction equation.

[0118] Optionally, the Jacobian matrices of the main grid electrical island, the left distribution network electrical island, and the right distribution network electrical island are H, L, and R, respectively. Correspondingly, the state variable Δx in the Jacobian matrices of the main grid electrical island, the left distribution network electrical island, and the right distribution network electrical island is set as: ΔX H ΔXL ΔX R Furthermore, the active power deviation and reactive power deviation at the connection point between the left-side distribution network electrical island and the main network electrical island are respectively: ΔP MC ΔQ MC The active power deviation and reactive power deviation at the connection point between the right-side distribution network electrical island and the main network electrical island are respectively: ΔP ND and ΔQ ND The active power deviation and reactive power deviation at the connection points between the left and right electrical islands of the distribution network are respectively: ΔP AB ΔQ AB .

[0119] Furthermore, for the main grid electrical island, the left distribution network electrical island, and the right distribution network electrical island, the Jacobian matrices are H, L, and R respectively, and the corresponding state variable Δx is set as: ΔX H ΔX L ΔX R Furthermore, the active power deviation and reactive power deviation at the connection point between the left-side distribution network electrical island and the main network electrical island are respectively: ΔP MC ΔQ MC The active power deviation and reactive power deviation at the connection point between the right-side distribution network electrical island and the main network electrical island are respectively: ΔP ND and ΔQ ND The active power deviation and reactive power deviation at the connection points between the left and right electrical islands of the distribution network are respectively: ΔP AB ΔQ AB It satisfies formula (23). Formula (23) is shown as follows:

[0120] ΔY H =HΔX H

[0121] ΔY L =LΔX L

[0122] ΔY R =RΔX R (twenty three)

[0123] Where, ΔY H The imbalance of the main grid electrical island, ΔY L The unbalance of the electrical island in the left-side distribution network is ΔY. R This represents the imbalance of the electrical island in the right-hand distribution network.

[0124] Power flow calculations are performed using the Newton-Raphson method and converted into matrix form, as shown in formula (24):

[0125]

[0126] in, and Let M, N, A, B, C, and D be the voltage magnitudes and phase angles of the boundary nodes M, N, A, B, C, and D between the target electrical islands. The first identity matrix is ​​obtained by taking partial derivatives from formulas (1) to (4), and the second Jacobian matrix is ​​obtained by matrix transformation. M -E N -E A -E B -E C and -E D The second identity matrix is ​​obtained by taking the partial derivatives of the power flow changes at each boundary node of the target electric island using the power flow change equations for boundary nodes M, N, A, B, C, and D, and then performing matrix transformation on the second Jacobian matrix.

[0127] Furthermore, in formulas (23) and (24), H, L, and R are the Jacobian matrices of the original three electrical islands, with dimensions of 2h×2h, 2l×2l, and 2r×2r, respectively. Wherein:

[0128]

[0129]

[0130]

[0131]

[0132]

[0133]

[0134] It is a 2×2h-order matrix whose M-th column is a 2×2 identity matrix, and all other elements are 0.

[0135]

[0136] It is a 2×2h-order matrix whose Nth column is a 2×2 identity matrix and all other elements are 0, i.e.:

[0137]

[0138] It is a 2×2 identity matrix with the Cth column as the first matrix, and a 2×2l matrix with all other elements being 0.

[0139]

[0140] It is a 2×2 identity matrix with the Dth column as the first matrix, and a 2×2r matrix with all other elements being 0.

[0141]

[0142] It is a 2×2 identity matrix with all other elements being 0, i.e.:

[0143]

[0144] It is a 2×2 r-order matrix with column B being a 2×2 identity matrix and all other elements being 0, i.e.:

[0145]

[0146] Specifically, the power flow correction equations for the active distribution network are constructed based on the third Jacobian matrix, active power deviation, and reactive power deviation, and the closed loop current of the active distribution network is calculated based on the power flow correction equations.

[0147] Optionally, calculating the closed-loop current of the active distribution network based on the power flow correction equation includes: iteratively solving the power flow correction equation using Gaussian elimination to determine the power flow distribution information at the switch position and the voltage magnitude and voltage phase angle of the associated boundary nodes of the closed and open loops; and calculating the closed-loop current of the active distribution network based on the power flow distribution information and the voltage magnitude and voltage phase angle of the associated boundary nodes.

[0148] Specifically, the power flow correction equation is solved iteratively using Gaussian elimination to determine the power flow distribution information at the switch position, as well as the voltage magnitude and voltage phase angle of the associated boundary nodes of the closed and open loops.

[0149] Specifically, the solution process for iteratively solving the power flow correction equations using Gaussian elimination is as follows:

[0150] The original equations of the power flow correction equations:

[0151]

[0152] Step 1:

[0153]

[0154] Step Two:

[0155]

[0156] in:

[0157]

[0158]

[0159]

[0160]

[0161] Step 3:

[0162]

[0163] in:

[0164]

[0165]

[0166]

[0167] ΔY R ′=ΔY R -E D A -1 ΔU ND ′

[0168]

[0169] Step Four:

[0170]

[0171] in:

[0172]

[0173]

[0174]

[0175] ΔY R ′=ΔY R -E D A -1 ΔU ND ′-E D A -1 BL′ -1 ΔY L ′

[0176]

[0177]

[0178] Step 5:

[0179]

[0180] in:

[0181]

[0182]

[0183]

[0184] ΔY R ′=ΔY R -E D A -1 ΔU ND ′-E D A -1 BL ′-1 ΔY L ′

[0185]

[0186]

[0187]

[0188] By substituting back, the first-order correction equation can be solved.

[0189] Furthermore, through multiple iterations, the power flow distribution of the newly formed ring network can be obtained to determine the power flow distribution information at the switch position and the voltage amplitude and voltage phase angle of the associated boundary nodes of the closed and open loops; the closed loop current of the active distribution network can be calculated based on the power flow distribution information and the voltage amplitude and voltage phase angle of the associated boundary nodes.

[0190] For example, with Figure 2 Taking the closed loop current at boundary node A and boundary node B as an example, by using this method to calculate the power flow distribution of the newly formed loop network and the voltage at each boundary node, the complex power S flowing through boundary node A and boundary node B can be calculated. AB =P AB +jQ AB and voltage Furthermore, based on the relationship between complex power and voltage / current in circuit theory: The closed-loop current can be obtained as follows:

[0191] The technical solution of this invention involves determining the switching position of the closed loop switch if a closed loop operation is detected in an active distribution network, and identifying the target electrical islands corresponding to the active distribution network based on the switch positions. These target electrical islands include the main grid electrical island, the left-side distribution network electrical island, and the right-side distribution network electrical island. For each electrical island, boundary node values ​​are obtained. For each target electrical island, power flow calculations are performed based on the Newton-Raphson method to obtain a first Jacobian matrix corresponding to the power flow balance information of the target electrical island before the closed loop switch and a second Jacobian matrix corresponding to the power flow change information of the target electrical island after the closed loop switch. By performing power flow calculations separately for each electrical island, the computational load in power flow calculations can be effectively reduced, and the calculation speed can be improved. Furthermore, power flow calculations are performed again after the closed loop switch is closed, improving the accuracy of the calculation of changes after the closed loop switch is closed. A third Jacobian matrix of the active distribution network is constructed based on the first and second Jacobian matrices corresponding to each target electrical island. The power flow correction equations are iteratively solved using Gaussian elimination, further reducing the amount of data and facilitating rapid calculation of results. By calculating the power flow of the three electrical islands and splicing the Jacobian matrix, the closed-loop current of the active distribution network is calculated. This solves the problem that calculating the closed-loop power flow of a large number of closed-loop switches would lead to excessively long power flow scanning calculation time, and enables fast calculation of closed-loop power flow.

[0192] Taking a real regional power grid as an example, assuming that the number of main grid nodes in the operating section is 958, the number of branch lines is 1069, and there are a total of 2272 feeders in the medium-voltage distribution network.

[0193] Using the active distribution network loop-closing current determination method of this invention, loop-closing current scanning calculations were performed on 1383 loopable switches in the distribution network. The calculation time spent by the central processing unit (CPU) was approximately 37 seconds. If the main distribution network model is directly stitched together, treating the three target electrical islands as a single electrical island and performing power flow calculations on the loop-closing states of each switch, the number of computational nodes in the stitched network is 219470, and the number of branches is 221223. The CPU calculation time for the loop-closing current is approximately 487 minutes. Therefore, the active distribution network loop-closing current determination method proposed in this invention, by dividing the target electrical islands and employing efficient sparse matrix processing technology, can significantly shorten the calculation time for batch loop-closing current scanning, better meeting the application requirements for online real-time loop-closing current scanning.

[0194] Figure 5 This is a schematic diagram of the structure of a device for determining the closed-loop current of an active power distribution network according to an embodiment of the present invention. Figure 5 As shown, it includes: a closed-loop detection module 410, a power flow calculation module 420, and a closed-loop current calculation module 430, wherein:

[0195] The loop closing detection module 410 is used to determine the switch position of the closed loop switch if a loop closing operation for an active distribution network is detected, and to determine the target electrical island corresponding to the active distribution network based on the switch position, wherein the target electrical island includes the main grid electrical island, the left distribution network electrical island and the right distribution network electrical island;

[0196] The power flow calculation module 420 is used to perform power flow calculation on each target electrical island based on the Newton-Raphson method to obtain a first Jacobian matrix corresponding to the power flow balance information of the target electrical island before the closing of the loop switch and a second Jacobian matrix corresponding to the power flow change information of the target electrical island after the closing of the loop switch.

[0197] The loop current calculation module 430 is used to construct the third Jacobian matrix of the active distribution network based on the first Jacobian matrix and the second Jacobian matrix corresponding to each of the target electrical islands, and to calculate the loop current of the active distribution network based on the third Jacobian matrix.

[0198] The technical solution of this invention involves determining the switching position of the closed loop switch if a closed loop operation is detected in an active distribution network, and identifying the target electrical island corresponding to the active distribution network based on the switch position. The target electrical island includes a main grid electrical island, a left-side distribution network electrical island, and a right-side distribution network electrical island. For each electrical island, node values ​​are obtained. For each target electrical island, power flow calculation is performed based on the Newton-Raphson method to obtain a first Jacobian matrix corresponding to the power flow balance information of the target electrical island before the closed loop switch is closed, and a second Jacobian matrix corresponding to the power flow change information of the target electrical island after the closed loop switch is closed. By performing power flow calculation separately for each electrical island, the computational load in power flow calculation can be effectively reduced, and the calculation speed can be improved. Power flow calculation is performed again after the closed loop switch is closed, improving the accuracy of the closed loop switch change calculation. A third Jacobian matrix of the active distribution network is constructed based on the first and second Jacobian matrices corresponding to each target electrical island, and the closed loop current of the active distribution network is calculated based on the third Jacobian matrix. By calculating the power flow of the three electrical islands and splicing the Jacobian matrix, the closed-loop current of the active distribution network is calculated. This solves the problem that calculating the closed-loop power flow of a large number of closed-loop switches would lead to excessively long power flow scanning calculation time, and enables fast calculation of closed-loop power flow.

[0199] Optionally, the power flow calculation module 420 is specifically used for:

[0200] At least two power flow calculation nodes of the target electrical island are identified, wherein the power flow calculation nodes include the boundary nodes of the target electrical island;

[0201] The first power flow balance equations of each power flow calculation node are constructed before the closing of the loop switch to obtain a set of power flow equations. The power flow is calculated using the Newton-Raphson method to obtain the first Jacobian matrix.

[0202] Determine the power flow change information of the boundary nodes of the target electrical island before and after the loop switch is closed, and construct a second Jacobian matrix based on the power flow change information.

[0203] Optionally, the power flow calculation module 420 is further used for:

[0204] The voltage amplitude constraint equation and voltage phase angle constraint equation for each boundary node of the target electrical island after the loop switch is closed are respectively constructed, as well as the power flow change equation for each boundary node;

[0205] The second Jacobian matrix is ​​constructed based on the voltage magnitude constraint equation, the voltage phase angle constraint equation, and the power flow change equation.

[0206] Optionally, the power flow calculation module 420 is further used for:

[0207] By taking the partial derivatives of the voltage amplitude constraint equation and the voltage phase angle constraint equation with respect to voltage amplitude and voltage phase, respectively, the first identity matrix corresponding to the target electrical island is obtained.

[0208] The tidal current change amount in the tidal current change equation is determined according to the first tidal current balance equation corresponding to the boundary node. The partial derivative of the tidal current change equation with respect to the tidal current change amount is obtained to obtain the second identity matrix corresponding to the target electric island.

[0209] The second Jacobian matrix is ​​determined based on the first identity matrix and the second identity matrix, respectively.

[0210] Optionally, the closed-loop current calculation module 430 is specifically used for:

[0211] The first Jacobian matrix and the second Jacobian matrix corresponding to each of the target electrical islands are concatenated, and the concatenated matrix is ​​sparsified to obtain the third Jacobian matrix of the active distribution network, wherein the first Jacobian matrix of the main grid electrical island is located at the upper left corner of the third Jacobian matrix.

[0212] Optionally, the closed-loop current calculation module 430 is further used for:

[0213] Determine the active power deviation and reactive power deviation at the connection points between the left distribution network electrical island and the main network electrical island, the right distribution network electrical island and the main network electrical island, and the left distribution network electrical island and the right distribution network electrical island;

[0214] The power flow correction equations for the active distribution network are constructed based on the third Jacobian matrix, the active power deviation, and the reactive power deviation. The closed loop current of the active distribution network is then calculated based on the power flow correction equations.

[0215] Optionally, the closed-loop current calculation module 430 is further used for:

[0216] The power flow correction equation is solved iteratively by Gaussian elimination to determine the power flow distribution information at the switch position and the voltage amplitude and voltage phase angle of the associated nodes of the closed and open loops.

[0217] The closed-loop current of the active distribution network is calculated based on the power flow distribution information and the voltage amplitude and voltage phase angle of the associated nodes.

[0218] The device for determining the closed-loop current of an active distribution network provided in this embodiment of the invention can execute the method for determining the closed-loop current of an active distribution network provided in any embodiment of the invention, and has the corresponding functional modules and beneficial effects of the method.

[0219] Figure 6 A schematic diagram of an electronic device 10 that can be used to implement embodiments of the present invention is shown. The electronic device is intended to represent various forms of digital computers, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device can also represent various forms of mobile devices, such as personal digital processors, cellular phones, smartphones, wearable devices (e.g., helmets, glasses, watches, etc.), and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely illustrative and are not intended to limit the implementation of the invention described and / or claimed herein.

[0220] like Figure 6 As shown, the electronic device 10 includes at least one processor 11 and a memory, such as a read-only memory (ROM) 12 or a random access memory (RAM) 13, communicatively connected to the at least one processor 11. The memory stores computer programs executable by the at least one processor. The processor 11 can perform various appropriate actions and processes based on the computer program stored in the ROM 12 or loaded from storage unit 18 into the RAM 13. The RAM 13 may also store various programs and data required for the operation of the electronic device 10. The processor 11, ROM 12, and RAM 13 are interconnected via a bus 14. An input / output (I / O) interface 15 is also connected to the bus 14.

[0221] Multiple components in electronic device 10 are connected to I / O interface 15, including: input unit 16, such as keyboard, mouse, etc.; output unit 17, such as various types of displays, speakers, etc.; storage unit 18, such as disk, optical disk, etc.; and communication unit 19, such as network card, modem, wireless transceiver, etc. Communication unit 19 allows electronic device 10 to exchange information / data with other devices through computer networks such as the Internet and / or various telecommunications networks.

[0222] Processor 11 can be a variety of general-purpose and / or special-purpose processing components with processing and computing capabilities. Some examples of processor 11 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various special-purpose artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, a digital signal processor (DSP), and any suitable processor, controller, microcontroller, etc. Processor 11 performs the various methods and processes described above, such as the method for determining the closed-loop current in an active power distribution network.

[0223] In some embodiments, the method for determining the closed-loop current of an active distribution network can be implemented as a computer program tangibly contained in a computer-readable storage medium, such as storage unit 18. In some embodiments, part or all of the computer program can be loaded and / or installed on electronic device 10 via ROM 12 and / or communication unit 19. When the computer program is loaded into RAM 13 and executed by processor 11, one or more steps of the method for determining the closed-loop current of an active distribution network described above can be performed. Alternatively, in other embodiments, processor 11 can be configured to perform the method for determining the closed-loop current of an active distribution network by any other suitable means (e.g., by means of firmware).

[0224] Various embodiments of the systems and techniques described above herein can be implemented in digital electronic circuit systems, integrated circuit systems, field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), application-specific standard products (ASSPs), systems-on-a-chip (SoCs), payload-programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various embodiments may include implementations in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which may be a dedicated or general-purpose programmable processor, capable of receiving data and instructions from a storage system, at least one input device, and at least one output device, and transmitting data and instructions to the storage system, the at least one input device, and the at least one output device.

[0225] Computer programs used to implement the methods of the present invention may be written in any combination of one or more programming languages. These computer programs may be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, such that when executed by the processor, the computer programs cause the functions / operations specified in the flowcharts and / or block diagrams to be performed. The computer programs may be executed entirely on a machine, partially on a machine, or as a standalone software package, partially on a machine and partially on a remote machine, or entirely on a remote machine or server.

[0226] In the context of this invention, a computer-readable storage medium can be a tangible medium that may contain or store a computer program for use by or in conjunction with an instruction execution system, apparatus, or device. A computer-readable storage medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination thereof. Alternatively, a computer-readable storage medium may be a machine-readable signal medium. More specific examples of machine-readable storage media include electrical connections based on one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof.

[0227] To provide interaction with a user, the systems and techniques described herein can be implemented on an electronic device having: a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user; and a keyboard and pointing device (e.g., a mouse or trackball) through which the user provides input to the electronic device. Other types of devices can also be used to provide interaction with the user; for example, feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form (including sound input, voice input, or tactile input).

[0228] The systems and technologies described herein can be implemented in computing systems that include backend components (e.g., as data servers), or computing systems that include middleware components (e.g., application servers), or computing systems that include frontend components (e.g., user computers with graphical user interfaces or web browsers through which users can interact with implementations of the systems and technologies described herein), or any combination of such backend, middleware, or frontend components. The components of the system can be interconnected via digital data communication of any form or medium (e.g., communication networks). Examples of communication networks include local area networks (LANs), wide area networks (WANs), blockchain networks, and the Internet.

[0229] A computing system can include clients and servers. Clients and servers are generally located far apart and typically interact through communication networks. The client-server relationship is created by computer programs running on the respective computers and having a client-server relationship with each other. The server can be a cloud server, also known as a cloud computing server or cloud host, which is a hosting product within the cloud computing service system to address the shortcomings of traditional physical hosts and VPS services, such as high management difficulty and weak business scalability.

[0230] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0231] Example 5

[0232] This embodiment provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of the active distribution network closing current determination method provided in any embodiment of the present invention. The method includes:

[0233] If a loop-closing operation is detected for an active distribution network, the switch position of the operated loop-closing switch is determined, and the target electrical island corresponding to the active distribution network is determined based on the switch position. The target electrical island includes the main grid electrical island, the left distribution network electrical island, and the right distribution network electrical island.

[0234] For each target electrical island, power flow calculation is performed on the target electrical island based on the Newton-Raphson method to obtain a first Jacobian matrix corresponding to the power flow balance information of the target electrical island before the closing of the loop switch and a second Jacobian matrix corresponding to the power flow change information of the target electrical island after the closing of the loop switch.

[0235] The third Jacobian matrix of the active distribution network is constructed based on the first Jacobian matrix and the second Jacobian matrix corresponding to each of the target electrical islands, and the loop current of the active distribution network is calculated based on the third Jacobian matrix.

[0236] The computer storage medium of this invention can be any combination of one or more computer-readable media. A computer-readable medium can be a computer-readable signal medium or a computer-readable storage medium. For example, a computer-readable storage medium can be, but is not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples (a non-exhaustive list) of computer-readable storage media include: an electrical connection having one or more wires, a portable computer disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination thereof. In this document, a computer-readable storage medium can be any tangible medium that contains or stores a program that can be used by or in conjunction with an instruction execution system, apparatus, or device.

[0237] Computer-readable signal media may include data signals propagated in baseband or as part of a carrier wave, carrying computer-readable program code. Such propagated data signals may take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. Computer-readable signal media may also be any computer-readable medium other than computer-readable storage media, capable of sending, propagating, or transmitting programs for use by or in connection with an instruction execution system, apparatus, or device.

[0238] Program code contained on a computer-readable medium may be transmitted using any suitable medium, including but not limited to: wireless, wire, optical fiber, RF, etc., or any suitable combination thereof.

[0239] Computer program code for performing the operations of this invention can be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, and C++, as well as conventional procedural programming languages—such as the "C" language or similar programming languages. The program code can be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving remote computers, the remote computer can be connected to the user's computer via any type of network, including a local area network (LAN) or a wide area network (WAN), or it can be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0240] Those skilled in the art will understand that the modules or steps of the present invention described above can be implemented using general-purpose computing devices. They can be centralized on a single computing device or distributed across a network of multiple computing devices. Optionally, they can be implemented using computer-executable program code, thereby allowing them to be stored in a storage device for execution by a computing device, or they can be fabricated as separate integrated circuit modules, or multiple modules or steps can be fabricated as a single integrated circuit module. Thus, the present invention is not limited to any particular combination of hardware and software.

[0241] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0242] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A method for determining the closed-loop current of an active distribution network, characterized in that, include: If a loop-closing operation is detected for an active distribution network, the switch position of the operated loop-closing switch is determined, and the target electrical island corresponding to the active distribution network is determined based on the switch position. The target electrical island includes the main grid electrical island, the left distribution network electrical island, and the right distribution network electrical island. For each target electrical island, power flow calculation is performed on the target electrical island based on the Newton-Raphson method to obtain a first Jacobian matrix corresponding to the power flow balance information of the target electrical island before the closing of the loop switch and a second Jacobian matrix corresponding to the power flow change information of the target electrical island after the closing of the loop switch. The third Jacobian matrix of the active distribution network is constructed based on the first Jacobian matrix and the second Jacobian matrix corresponding to each of the target electrical islands, and the loop current of the active distribution network is calculated based on the third Jacobian matrix. The step of constructing the third Jacobian matrix of the active distribution network based on the first Jacobian matrix and the second Jacobian matrix corresponding to each of the target electrical islands includes: The first Jacobian matrix and the second Jacobian matrix corresponding to each of the target electrical islands are concatenated, and the concatenated matrix is ​​sparsified to obtain the third Jacobian matrix of the active distribution network, wherein the first Jacobian matrix of the main grid electrical island is located at the upper left corner of the third Jacobian matrix. The calculation of the closed-loop current of the active distribution network based on the third Jacobian matrix includes: Determine the active power deviation and reactive power deviation at the connection points between the left distribution network electrical island and the main network electrical island, the right distribution network electrical island and the main network electrical island, and the left distribution network electrical island and the right distribution network electrical island; The power flow correction equations for the active distribution network are constructed based on the third Jacobian matrix, the active power deviation, and the reactive power deviation. The closed loop current of the active distribution network is then calculated based on the power flow correction equations.

2. The method according to claim 1, characterized in that, The power flow calculation based on the Newton-Raphson method for the target electrical island, obtaining a first Jacobian matrix corresponding to the power flow balance information of the target electrical island before the closing of the loop switch, and a second Jacobian matrix corresponding to the power flow change information of the target electrical island after the closing of the loop switch, includes: At least two power flow calculation nodes of the target electrical island are identified, wherein the power flow calculation nodes include the boundary nodes of the target electrical island; The first power flow balance equations of each power flow calculation node are constructed before the closing of the loop switch to obtain a set of power flow equations. The power flow is calculated using the Newton-Raphson method to obtain the first Jacobian matrix. Determine the power flow change information of the boundary nodes of the target electrical island before and after the loop switch is closed, and construct a second Jacobian matrix based on the power flow change information.

3. The method according to claim 2, characterized in that, The process of determining the power flow change information of the boundary nodes of the target electrical island before and after the loop switch is closed, and constructing a second Jacobian matrix based on the power flow change information, includes: The voltage amplitude constraint equation and voltage phase angle constraint equation for each boundary node of the target electrical island after the loop switch is closed are respectively constructed, as well as the power flow change equation for each boundary node; The second Jacobian matrix is ​​constructed based on the voltage magnitude constraint equation, the voltage phase angle constraint equation, and the power flow change equation.

4. The method according to claim 3, characterized in that, The construction of the second Jacobian matrix based on the voltage magnitude constraint equation, the voltage phase angle constraint equation, and the power flow variation equation includes: By taking the partial derivatives of the voltage amplitude constraint equation and the voltage phase angle constraint equation with respect to voltage amplitude and voltage phase, respectively, the first identity matrix corresponding to the target electrical island is obtained. The tidal current change amount in the tidal current change equation is determined according to the first tidal current balance equation corresponding to the boundary node. The partial derivative of the tidal current change equation with respect to the tidal current change amount is obtained to obtain the second identity matrix corresponding to the target electric island. The second Jacobian matrix is ​​determined based on the first identity matrix and the second identity matrix, respectively.

5. The method according to claim 1, characterized in that, The calculation of the closed-loop current of the active distribution network based on the power flow correction equation includes: The power flow correction equation is solved iteratively by Gaussian elimination to determine the power flow distribution information at the switch position and the voltage amplitude and voltage phase angle of the associated nodes of the closed and open loops. The closed-loop current of the active distribution network is calculated based on the power flow distribution information and the voltage amplitude and voltage phase angle of the associated nodes.

6. A device for determining the closed-loop current of an active distribution network, capable of executing the method for determining the closed-loop current of an active distribution network according to any one of claims 1-5, characterized in that, include: The loop-closing detection module is used to determine the switch position of the operated loop-closing switch if a loop-closing operation for an active distribution network is detected, and to determine the target electrical island corresponding to the active distribution network based on the switch position. The target electrical island includes the main grid electrical island, the left distribution network electrical island, and the right distribution network electrical island. The power flow calculation module is used to perform power flow calculation on each target electrical island based on the Newton-Raphson method to obtain a first Jacobian matrix corresponding to the power flow balance information of the target electrical island before the closing of the loop switch and a second Jacobian matrix corresponding to the power flow change information of the target electrical island after the closing of the loop switch. The loop current calculation module is used to construct the third Jacobian matrix of the active distribution network based on the first Jacobian matrix and the second Jacobian matrix corresponding to each of the target electrical islands, and to calculate the loop current of the active distribution network based on the third Jacobian matrix.

7. An electronic device, characterized in that, The electronic device includes: At least one processor; and A memory communicatively connected to the at least one processor; wherein, The memory stores a computer program that can be executed by the at least one processor, the computer program being executed by the at least one processor to enable the at least one processor to perform the method for determining the closed loop current of the active distribution network according to any one of claims 1-5.

8. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions that, when executed by a processor, implement the method for determining the closed-loop current of an active power distribution network as described in any one of claims 1-5.

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