Method and device for determining the location of an embedded dc grid connection based on system coupling characteristics

Abstract

The application discloses an embedded direct-current grid-connection position determination method and device based on system coupling characteristics, and relates to the technical field of power transmission. The method comprises the following steps: performing calculation and processing based on first structural parameters of a target area power grid and an embedded direct-current system to be grid-connected, so as to obtain a voltage stiffness index; when the voltage stiffness index meets a preset voltage stiffness constraint condition, performing calculation and processing based on second structural parameters and operating parameters of a fault blocking simulation pre-fault flow transfer branch, so as to obtain a current parameter after fault blocking simulation; when the current parameter meets a preset current constraint condition corresponding to the flow transfer branch, calculating a multi-infeed interaction factor index and a voltage-reactive power sensitivity index; and when the multi-infeed interaction factor index and the voltage-reactive power sensitivity index meet a preset condition, determining a candidate grid-connection position as a target grid-connection position. The application can provide a reference for embedded direct-current planning and operation, and guarantee the safe and stable operation of an AC-DC power grid.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power transmission, in particular to a method and device for determining an embedded DC grid-connected position based on system coupling characteristics, a storage medium and an electronic device. BACKGROUND

[0002] With the increasing complexity of power grid structure and the continuous expansion of source and load scale, the provincial grid structure gradually presents problems such as excessive short-circuit current and limited carrying capacity of key sections. Embedded DC is a kind of DC power transmission system with sending and receiving ends located in a synchronous power grid, which is a form of power grid strengthening and mainly plays a role in power flow control and grid optimization. However, the current engineering practice experience of embedded DC is still insufficient. The construction of embedded DC will have an impact on the operation characteristics of the power system, and the interaction mechanism between the two is not clear. The lack of analysis methods for analyzing the coupling characteristics of embedded DC and existing AC / DC systems leads to problems such as power transmission congestion and excessive short-circuit current. SUMMARY

[0003] Therefore, the present application provides a method and device for determining an embedded DC grid-connected position based on system coupling characteristics, a storage medium and an electronic device, which mainly aims to solve the problem of power transmission congestion and excessive short-circuit current caused by the lack of analysis methods for analyzing the coupling characteristics of embedded DC and existing AC / DC systems.

[0004] To solve the above problems, the present application provides a method for determining an embedded DC grid-connected position based on system coupling characteristics, which comprises:

[0005] Based on the first structural parameters of the target regional power grid and the embedded DC system to be grid-connected, the voltage stiffness index of the embedded DC system at the candidate grid-connected position is obtained through calculation and processing;

[0006] When the voltage stiffness index meets the preset voltage stiffness constraint condition, fault locking simulation is performed on the embedded DC system, and based on the second structural parameters and operating parameters of the power flow transfer branch before fault locking simulation, the current parameters of the embedded DC system after fault locking simulation corresponding to the power flow transfer branch are obtained through calculation and processing;

[0007] When the current parameters meet the preset current constraint condition corresponding to the power flow transfer branch, the multi-infeed interaction factor index and the voltage-reactive power sensitivity index between the embedded DC system and the original DC system in the target regional power grid are calculated;

[0008] When the multi-infeed interaction factor index and the voltage-reactive power sensitivity index meet the preset condition, the candidate grid-connected position is determined as the target grid-connected position of the embedded DC system.

[0009] Optionally, the first structural parameters of the target regional power grid and the embedded direct-current system to be connected to the grid are calculated and processed to obtain a voltage stiffness index of the embedded direct-current system at the candidate grid-connected position, specifically comprising:

[0010] A Thevenin equivalent circuit comprising the target regional power grid and the embedded direct-current system is constructed.

[0011] The Thevenin equivalent circuit is calculated based on the first structural parameters of the target regional power grid and the embedded direct-current system to be connected to the grid, to obtain a Thevenin equivalent potential and a first Thevenin equivalent impedance of the target regional power grid at the candidate grid-connected position.

[0012] The Thevenin equivalent potential, the first Thevenin equivalent impedance, and the second equivalent impedance of the embedded direct-current system are calculated and processed to obtain a voltage stiffness index of the embedded direct-current system at the candidate grid-connected position.

[0013] Optionally, when the voltage stiffness index meets a preset voltage stiffness constraint condition, a fault lockout simulation is performed on the embedded direct-current system, and the second structural parameters and operating parameters of the power flow transfer branch before the fault lockout simulation are calculated and processed to obtain a current parameter corresponding to the fault lockout simulation of the power flow transfer branch, specifically comprising:

[0014] When the voltage stiffness index is greater than or equal to a preset voltage stiffness threshold value, a fault lockout simulation is performed on the embedded direct-current system to obtain a pre-fault current parameter of the candidate grid-connected position before the fault lockout simulation;

[0015] The admittance parameter of the power flow transfer branch and the current parameter are calculated and processed to obtain a power flow transfer factor corresponding to the power flow transfer branch;

[0016] The current parameter and the power flow transfer factor are multiplied to obtain a power flow transfer component corresponding to the power flow transfer branch;

[0017] The power flow transfer component and the current parameter are added to obtain the current parameter of the power flow transfer branch after the fault lockout simulation.

[0018] Optionally, when the current parameter meets a preset current constraint condition corresponding to the power flow transfer branch, a multi-infeed interaction factor index and a voltage-reactive sensitivity index between the embedded direct-current system and the original direct-current system in the target regional power grid are calculated, specifically comprising:

[0019] when the current parameter is less than or equal to the maximum current value corresponding to the power flow transfer branch, performing calculation and processing based on voltage parameters of the original DC system and the embedded DC system to obtain a multi-infeed interaction factor index;

[0020] adopting a voltage-reactive power sensitivity evaluation method to evaluate reactive power and voltage micro-increment changes of the embedded DC system at the candidate grid-connected position to obtain a voltage-reactive power sensitivity index.

[0021] Optionally, the calculation and processing based on the voltage parameters of the original DC system and the embedded DC system to obtain the multi-infeed interaction factor index specifically include:

[0022] obtaining a first voltage parameter of the original DC system before the embedded DC system is at the candidate grid-connected position, a second voltage parameter of the original DC system after the embedded DC system is at the candidate grid-connected position, and a third voltage parameter of the embedded DC system at the candidate grid-connected position;

[0023] performing subtraction operation and processing based on the first voltage parameter and the second voltage parameter to obtain a first difference value;

[0024] performing absolute value calculation and processing on the first difference value to obtain a voltage change amount;

[0025] performing calculation and processing based on the power change amount, the third voltage parameter, and a predetermined voltage drop parameter to obtain the multi-infeed interaction factor index.

[0026] Optionally, the adoption of the voltage-reactive power sensitivity evaluation method to evaluate the reactive power and voltage micro-increment changes of the embedded DC system at the candidate grid-connected position to obtain the voltage-reactive power sensitivity index specifically includes:

[0027] constructing a power flow calculation correction equation;

[0028] performing conversion on the correction equation to obtain a conversion equation under the condition that active power is unchanged;

[0029] solving the conversion equation based on a first operating parameter of the embedded DC system before the embedded DC system is at the candidate grid-connected position and a second operating parameter of the embedded DC system after the embedded DC system is at the candidate grid-connected position to obtain the voltage-reactive power sensitivity index of the embedded DC system at the candidate grid-connected position.

[0030] Optionally, the method further includes:

[0031] when the voltage stiffness index does not satisfy a preset voltage stiffness constraint condition, or the current parameter does not satisfy a preset current constraint condition corresponding to the power flow transfer branch, or the multi-infeed interaction factor index and the voltage-reactive power sensitivity index do not satisfy a preset condition, the candidate grid-connected position is excluded.

[0032] To solve the above problems, the application provides an embedded direct-current grid-connected position determination device based on system coupling characteristics, which comprises:

[0033] A first calculation module is configured to perform calculation and processing based on first structural parameters of a target regional power grid and an embedded direct-current system to be grid-connected, so as to obtain a voltage stiffness index of the embedded direct-current system at a candidate grid-connected position.

[0034] A second calculation module is configured to, when the voltage stiffness index satisfies a preset voltage stiffness constraint condition, perform fault blocking simulation on the embedded direct-current system, perform calculation and processing based on second structural parameters and operating parameters of a power flow transfer branch before fault blocking simulation, so as to obtain a current parameter of the power flow transfer branch after fault blocking simulation.

[0035] A third calculation module is configured to, when the current parameter satisfies a preset current constraint condition corresponding to the power flow transfer branch, calculate a multi-infeed interaction factor index and a voltage-reactive power sensitivity index between the embedded direct-current system and an original direct-current system in the target regional power grid.

[0036] A determination module is configured to, when the multi-infeed interaction factor index and the voltage-reactive power sensitivity index satisfy a preset condition, determine the candidate grid-connected position as a target grid-connected position of the embedded direct-current system.

[0037] To solve the above problems, the application provides a storage medium, which stores a computer program. When the computer program is executed by a processor, the steps of the embedded direct-current grid-connected position determination method based on system coupling characteristics are implemented.

[0038] To solve the above problems, the application provides an electronic device, which at least comprises a memory and a processor. The memory stores a computer program. When the processor executes the computer program stored in the memory, the steps of the embedded direct-current grid-connected position determination method based on system coupling characteristics are implemented.

[0039] The beneficial effects in the application: the application obtains the voltage support of the alternating current power grid to the embedded direct current system through the calculation of the voltage stiffness of the preset embedded direct current system access point, excludes the candidate grid-connected position that does not meet the voltage support, and preliminarily screens the candidate grid-connected position; when the voltage support of the access point meets the condition, the current parameters after fault blocking simulation corresponding to the power flow transfer branch reflecting the power flow coupling degree of the alternating current line and the embedded direct current system are calculated, the candidate grid-connected position that may cause large-scale power flow transfer and cause overload of the multi-loop alternating current line is excluded, and the candidate grid-connected position is further screened; finally, the multi-infeed interaction factor index and the voltage-reactive power sensitivity index between the embedded direct current system and the original direct current system in the target regional power grid are calculated, which are used for evaluating the voltage coupling characteristics between the embedded direct current and the existing direct current system, the candidate grid-connected position that finally meets the preset condition of the multi-infeed interaction factor index and the voltage-reactive power sensitivity index is determined as the target grid-connected position of the embedded direct current system, and the candidate grid-connected position with high voltage coupling degree between direct current systems is excluded, so that the application can provide a reference for the planning and operation of the embedded direct current, and guarantee the safe and stable operation of the alternating current and direct current power grid.

[0040] The above description is only a summary of the technical scheme of the application. In order to enable the technical means of the application to be more clearly understood, and to be implemented according to the content of the specification, and in order to enable the above and other purposes, characteristics and advantages of the application to be more apparent and easy to understand, the following specific embodiments of the application are described. BRIEF DESCRIPTION OF DRAWINGS

[0041] Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The accompanying drawings are intended to further assist in understanding the preferred embodiments, and are not considered limiting of the present application. Moreover, like reference numerals denote like parts throughout the several views in the drawings. In the drawings:

[0042] Figure 1 A flowchart of a system coupling characteristic-based embedded direct current grid-connected position determination method provided by an embodiment of the application is shown;

[0043] Figure 2 A flowchart of a system coupling characteristic-based embedded direct current grid-connected position determination method provided by another embodiment of the application is shown;

[0044] Figure 3 A circuit structure schematic diagram of a Thevenin equivalent circuit including the target regional power grid and the embedded direct current system of the embodiment of the application is shown;

[0045] Figure 4 A power flow transfer factor solving equivalent network circuit structure schematic diagram of the embodiment of the application is shown.

[0046] Figure 5 A structure block diagram of an embedded direct current grid-connected position determination device based on system coupling characteristics provided by another embodiment of the application is shown. DETAILED DESCRIPTION

[0047] Various aspects and features of the present application are described herein with reference to the drawings.

[0048] It is to be understood that various alterations, modifications, and improvements can be made to the embodiments of the application herein disclosed. Accordingly, it is intended to embrace all such alterations, modifications, and improvements as fall within the scope and spirit of the application.

[0049] The accompanying drawings incorporated in and forming a part of the specification illustrate embodiments of the present application and, together with the general description of the application given above, and the detailed description of the embodiments given below, serve to explain the principles of the present application.

[0050] These and other characteristics of the present application will become apparent from the following description and appended claims, taken in conjunction with the accompanying drawings.

[0051] It should also be understood that, although the terms "first" and "second" are used herein to describe various elements and / or steps, these elements and / or steps should not be limited by these terms. These terms are only used to distinguish one element or step from another. Thus, a first element could be termed a second element without departing from the scope of the present application.

[0052] The above and other aspects, features, and advantages of the present application will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings in which:

[0053] Specific embodiments of the present application are described herein with reference to the accompanying drawings. However, it will be apparent to those having ordinary skill in the art that a variety of modifications and changes can be made to the embodiments described without departing from the scope and spirit of the application. Accordingly, all such modifications and changes are intended to be included within the scope of the application.

[0054] The specification can use phrases like "in one embodiment", "in another embodiment", "in yet another embodiment", or "in other embodiments", which can refer to one or more of the same or different embodiments of the application.

[0055] An embedded direct current grid-connected position determination method based on system coupling characteristics is provided by embodiments of the present application, as shown in Figure 1 The method comprises the steps of:

[0056] Step S101: based on the first structural parameters of the target regional power grid and the embedded direct current system to be connected to the grid, a voltage stiffness index of the embedded direct current system at the candidate grid-connected position is obtained through calculation and processing;

[0057] In the specific implementation process, the Thevenin equivalent circuit containing the target regional power grid and the embedded direct current system is constructed, and the voltage stiffness index of the embedded direct current system at the candidate grid-connected position is obtained by calculating the Thevenin equivalent circuit based on the first structural parameters of the target regional power grid and the embedded direct current system to be connected to the grid. The first structural parameters include node voltage, impedance and other parameters.

[0058] Step S102: when the voltage stiffness index meets the preset voltage stiffness constraint condition, fault locking simulation is performed on the embedded direct current system, and based on the second structural parameters and operating parameters of the power flow transfer branch before fault locking simulation, a current parameter after fault locking simulation corresponding to the power flow transfer branch is obtained through calculation and processing;

[0059] In the specific implementation process, the second structural parameters include admittance parameters of the power flow transfer branch; the operating parameters include pre-fault current parameters of the power flow transfer branch before fault locking simulation; when the voltage stiffness index is greater than or equal to a preset voltage stiffness threshold, fault locking simulation is performed on the embedded direct current system to obtain the pre-fault current parameters of the candidate grid-connected position before fault locking simulation; based on the admittance parameters of the power flow transfer branch and the current parameters, a power flow transfer factor corresponding to the power flow transfer branch is obtained through calculation and processing; based on the current parameters and the power flow transfer factor, a power flow transfer component corresponding to the power flow transfer branch is obtained through multiplication operation processing; based on the power flow transfer component and the current parameters, the current parameters after fault locking simulation corresponding to the power flow transfer branch after fault locking simulation are obtained through addition operation processing.

[0060] Step S103: when the current parameter meets the preset current constraint condition corresponding to the power flow transfer branch, a multi-infeed interaction factor index and a voltage-reactive power sensitivity index between the embedded direct current system and the original direct current system in the target regional power grid are calculated;

[0061] In the specific implementation process, when the current parameter is less than or equal to the maximum current value corresponding to the power flow transfer branch, a multi-infeed interaction factor index is obtained through calculation and processing based on the voltage parameters of the original direct current system and the embedded direct current system; the voltage-reactive power sensitivity index is obtained by evaluating the reactive power and voltage micro-increase change of the embedded direct current system at the candidate grid-connected position using a voltage-reactive power sensitivity evaluation method.

[0062] Step S104: When the multi-infeed interaction factor index and the voltage-reactive power sensitivity index meet preset conditions, the candidate grid-connected position is determined as the target grid-connected position of the embedded DC system.

[0063] In the specific implementation process, when the multi-infeed interaction factor is small, it indicates that the coupling degree between the two DC systems is small; if the multi-infeed interaction factor is large but the voltage-reactive power sensitivity is small, it indicates that the coupling degree between the two DC systems is also small; if the multi-infeed interaction factor is large and the voltage-reactive power sensitivity is also large, it indicates that the coupling degree between the two DC systems is large.

[0064] The application obtains the voltage support of the AC power grid on the embedded DC system through the calculation of the voltage stiffness of the preset embedded DC system access point, excludes the candidate grid-connected positions that do not meet the voltage support, and preliminarily screens the candidate grid-connected positions; when the voltage support of the access point meets the conditions, the current parameters after the fault blocking simulation of the power flow transfer branch that reflects the power flow coupling degree between the AC line and the embedded DC system are calculated, the candidate grid-connected positions that may cause large-scale power flow transfer and lead to overloading of the multi-loop AC line are excluded, and the candidate grid-connected positions are further screened; finally, the multi-infeed interaction factor index and the voltage-reactive power sensitivity index between the embedded DC system and the original DC system in the target regional power grid are calculated, which are used to evaluate the voltage-reactive power coupling characteristics between the embedded DC and the existing DC system, and the candidate grid-connected position that finally meets the preset conditions of the multi-infeed interaction factor index and the voltage-reactive power sensitivity index is determined as the target grid-connected position of the embedded DC system, which excludes the candidate grid-connected positions with high voltage coupling degree between the DC systems. The application can provide a reference for the planning and operation of the embedded DC, and ensure the safe and stable operation of the AC / DC power grid.

[0065] Another embodiment of the application provides another embedded DC grid-connected position determination method based on system coupling characteristics, as shown in Figure 2 , which comprises the following steps:

[0066] Step S201: constructing a Thevenin equivalent circuit comprising the target regional power grid and the embedded DC system;

[0067] In the specific implementation process, the Thevenin equivalent circuit comprising the target regional power grid and the embedded DC system is constructed as shown in Figure 3 , and the target regional power grid is represented by adopting a Thevenin equivalent potential and a Thevenin equivalent impedance in series. The Thevenin equivalent potential Eth is equal to the no-load voltage at the candidate grid-connected position SYS when the embedded DC system is not connected to the power grid , and the Thevenin equivalent impedance The equivalent impedance of the network as seen from the point SYS when each individual power supply in the fundamental frequency positive sequence network is zeroed.

[0068] Step S202: Calculate the Thevenin equivalent circuit based on the first structural parameters of the target regional power grid and the embedded direct-current system to be connected to the grid, to obtain the Thevenin equivalent potential and the first Thevenin equivalent impedance of the target regional power grid at the candidate grid-connected position;

[0069] In the specific implementation process, first, the first structural parameters representing the topological structure of the target regional power grid are obtained, including the parameters of lines, transformers, generators and other elements; based on the first structural parameters, a node admittance matrix Y n is constructed; the candidate grid-connected position of the embedded direct-current system to be connected to the grid is determined as an equivalent node; and the Thevenin equivalent potential and the first Thevenin equivalent impedance are calculated based on the equivalent node Specifically, the first Thevenin equivalent impedance can be calculated by the inverse matrix of the node admittance matrix. The Thevenin equivalent potential can be calculated by the node voltage equation.

[0070] Step S203: Perform calculation and processing based on the Thevenin equivalent potential, the first Thevenin equivalent impedance and the second equivalent impedance of the embedded direct-current system, to obtain the voltage stiffness index of the embedded direct-current system at the candidate grid-connected position;

[0071] In the specific implementation process, the second equivalent impedance of the embedded direct-current system is calculated and processed based on the electrical design parameters of the embedded direct-current system The first Thevenin equivalent impedance and the second equivalent impedance are subjected to addition operation processing to obtain the sum of Thevenin equivalent impedances, and the second equivalent impedance and the sum of Thevenin equivalent impedances are subjected to division operation processing to obtain the initial voltage stiffness index; the initial voltage stiffness index is subjected to absolute value operation processing to obtain the voltage stiffness index, and the calculation mathematical formula of the voltage stiffness index is shown in the following formula (1):

[0072]

[0073] Wherein, K vtg is the voltage stiffness, U sys is the voltage amplitude of the port of the grid-connected device after accessing the power grid, U sys0 is the no-load voltage amplitude of the access point, is the Thevenin equivalent impedance of the system, is the direct-current equivalent impedance.

[0074] The mathematical expression of the voltage stiffness constraint condition in the specific implementation process can be shown in the following formula (2):

[0075] K vtg ≥K vtgmin (2)

[0076] Wherein, K vtgmin is a voltage stiffness threshold value for meeting the voltage support strength of the AC system to the embedded DC system, the voltage stiffness threshold value can be 0.9, and the voltage stiffness threshold value can be set according to actual needs. The value range of the voltage stiffness K vtg is [0, 1]. When Z th is equal to zero, the voltage stiffness K vtg is equal to 1; when K vtg is equal to infinity, the voltage stiffness K vtg is equal to 0. Generally, when K vtg is greater than 0.9, the AC system is considered to be a strong system; when K vtg is less than 0.9, the AC system is considered to be a weak system, and there is a security risk; when K vtg is between 0.9 and 0.95, the AC system is considered to be a medium-strength system.

[0077] When the voltage stiffness index does not meet the preset voltage stiffness constraint condition, the candidate grid-connected position is excluded.

[0078] Step S204: When the voltage stiffness index is greater than or equal to the preset voltage stiffness threshold value, fault blocking simulation is performed on the embedded DC system, and a pre-fault current parameter of the candidate grid-connected position before the fault blocking simulation is obtained.

[0079] After the embedded DC system is fault blocked, the network topology structure changes, and the power flow on it will be transferred to other normally operating AC lines in the system. If the DC system capacity is large, it may cause large-scale power flow transfer, and in severe cases, it may even cause multi-loop AC line overload, ultimately threatening the safe and stable operation of the entire system. Assuming that the current injected into the network by each node in the system before and after the line l is cut off is unchanged, according to the superposition principle, the power flow distribution in the network after the line l is cut off can be considered to be composed of two parts: the power flow before the line l is cut off and the power flow transfer component caused by the line l cut-off. Since the power grid operates at a fixed frequency, the network parameters are basically a constant, which is related to the network topology structure and parameters. Therefore, the transfer power flow component is linearly related to the equivalent excitation source (a current source with the same size and opposite direction as the current on the line l before the fault). For example, Figure 4An equivalent network diagram for calculating the power flow transfer factor is shown, assuming that the system includes n nodes and b lines (including the cut-off branch), wherein the cut-off branch is numbered as branch b, and the corresponding nodes are numbered as the first end n and the last end n+1; the to-be-solved transferred branch is numbered as branch k, and the corresponding nodes are numbered as the first end l and the last end m. The fault current parameters of the candidate grid-connected position before the fault is simulated are collected is the current on the line k before the fault.

[0080] Step S205: Based on the admittance parameter of the power flow transfer branch and the current parameter, a power flow transfer factor corresponding to the power flow transfer branch is obtained through calculation and processing.

[0081] In the specific implementation process, the mathematical expression of the power flow transfer factor can be shown in the following formula (3):

[0082]

[0083] wherein, τ kb is the power flow transfer factor of branch b relative to branch k; is the current on the line k before the fault. is the power flow transfer component; Y k is the admittance of branch k, and Δ is the determinant of the node admittance matrix Y n . ni is the algebraic cofactor of the element in the nth row and the ith column (i=l, m) in the node admittance matrix Y n .

[0084] Step S206: Based on the current parameter and the power flow transfer factor, a power flow transfer component corresponding to the power flow transfer branch is obtained through multiplication operation processing.

[0085] In the specific implementation process, the mathematical expression of the power flow transfer component can be shown in the following formula (4):

[0086] I k,T = τ kl I b,M (4)

[0087] wherein, I b , M is the current on the line b before the fault, I k , T is the power flow transfer component; τ kb is the power flow transfer factor of branch k relative to branch b.

[0088] Step S207: performing an addition operation based on the power flow transfer component and the current parameter to obtain the current parameter corresponding to the power flow transfer branch after fault blocking simulation;

[0089] In the implementation process, the mathematical formula for calculating the current parameter can be shown in the following formula (5):

[0090] I = I k,T + I k,M (5)

[0091] Wherein: I k，M is the current on the line k before the fault, I k，T is the power flow transfer component; I is the current parameter.

[0092] In the implementation process, in order to ensure that the line is not overloaded, the mathematical formula that the line current after removal should satisfy can be shown in the following formula (6):

[0093] I k,T + I k,M ≤ I kmax (6)

[0094] Wherein, I kmax is the maximum current value that meets the safe operation of the line k. After the new embedded DC is built, the voltage coupling between the DC system and the original DC system will occur. If the voltage coupling between the DC systems is high, it may lead to simultaneous commutation failure of multiple DCs, threatening the safe and stable operation of the system.

[0095] Step S208: when the current parameter is less than or equal to the maximum current value corresponding to the power flow transfer branch, performing calculation based on the voltage parameters of the original DC system and the embedded DC system to obtain a multi-infeed interaction factor index;

[0096] I k,T + I k,M ≤ I kmaxFor the receiving-end system with multiple HVDC lines feeding in, especially in the case of concentrated DC drop points, the interaction between the HVDC lines cannot be ignored. In the multi-infeed HVDC system, the electrical distance between the DC inversion stations is short, and the interaction between DC and DC and between DC and AC is stronger. The result of this interaction makes the response of the DC system worse. In order to determine the influence of the interaction between the DCs on the commutation process, the multi-infeed interaction factor (MIIF) is used to evaluate the index. The definition is that when the symmetrical three-phase reactor is put into the commutation bus i so that the voltage drop on the bus is exactly 1%, the voltage change of the commutation bus j. The mathematical expression of the multi-infeed interaction factor index can be shown in the following formula (7):

[0097]

[0098] Where, when there are two DC commutation stations numbered i and j in the system, V i is the voltage of the AC bus of the commutation station i; and △V j is the voltage change of the AC bus of the commutation station j. The MIIF measures the voltage interaction between the two inversion stations, and the larger the MIIF, the higher the voltage coupling degree between the two commutation stations. By using the multi-infeed interaction factor, the coupling degree of different DC commutation buses can be estimated. Generally, when MIIF≥0.1, further security and stability verification of the embedded DC system scheme needs to be made in combination with simulation. The current parameter does not satisfy a preset current constraint condition corresponding to the power flow transfer branch, and the candidate grid-connected position is excluded.

[0099] Step S209: The voltage-reactive sensitivity evaluation method is used to evaluate the reactive power and voltage micro-increase change of the embedded DC system at the candidate grid-connected position, and a voltage-reactive sensitivity index is obtained.

[0100] In the specific implementation process of this step, a power flow calculation correction equation is constructed. The calculation mathematical formula of the correction equation can be shown in the following formula (8):

[0101]

[0102] Where, P is the active power vector; Q is the reactive power vector; θ is the node voltage angle vector; U is the node voltage amplitude vector, and J is the Jacobian matrix. The correction equation is converted under the condition that the active power is unchanged, and a conversion equation is obtained. By setting ΔP=0, i.e., keeping the active power unchanged, the following initial conversion equation (9) can be obtained:

[0103]

[0104] The conversion equation is obtained by deforming the initial conversion equation, and a mathematical expression of the conversion equation can be shown in the following formula (10):

[0105]

[0106] The conversion equation is solved based on a first operation parameter of the embedded DC system before the candidate grid-connected position and a second operation parameter of the embedded DC system after the candidate grid-connected position, to obtain the voltage-reactive power sensitivity index of the embedded DC system at the candidate grid-connected position. Specifically, the first operation parameter and the second operation parameter are calculated and processed to obtain a node voltage amplitude change vector and a reactive power change vector; the Jacobian matrix reflecting the voltage-reactive power sensitivity index is obtained based on the calculation and processing of the node voltage amplitude change vector and the reactive power change vector, and the matrix J R is a simplified U-Q Jacobian matrix. It is assumed that two DC converter stations are connected to node i and node j respectively, and the element J R of the ith row and jth column of J Rij represents the U-Q sensitivity of node i to node j. J Rij The greater the element J

[0107] Step S210: When the multi-infeed interaction factor index and the voltage-reactive power sensitivity index meet a preset condition, the candidate grid-connected position is determined as the target grid-connected position of the embedded DC system.

[0108] In the specific implementation process, if the multi-infeed interaction factor is small, it indicates that the electrical distance between the two DC systems is large and the coupling degree is small, and when the preset condition is met, the candidate grid-connected position is determined as the target grid-connected position of the embedded DC system. The multi-infeed interaction factor is greater than or equal to 0.1 when it is large, and less than 0.1 when it is small. If the multi-infeed interaction factor is large, but the voltage-reactive power sensitivity is small, it indicates that the electrical distance between the two DC systems is small, but the grid has strong reactive power fluctuation suppression effect on the converter station bus, and the coupling degree is small, and when the preset condition is met, the candidate grid-connected position is determined as the target grid-connected position of the embedded DC system. The value of the voltage-reactive power sensitivity is determined according to the relative size of each node of the entire target area power grid, and the value of the voltage-reactive power sensitivity is determined to be large or small. If the multi-infeed interaction factor is large and the voltage-reactive power sensitivity is also large, it indicates that the electrical distance between the two DC systems is small, and the grid has strong reactive power fluctuation suppression effect on the converter station bus, and the coupling degree is large. When the preset condition is not met, the candidate grid-connected position cannot be used as the target grid-connected position of the embedded DC system.

[0109] This application calculates the voltage stiffness of the pre-set embedded DC transmission system access point to obtain the voltage support effect of the AC grid on the embedded DC system, eliminating candidate grid connection locations that do not meet the voltage support effect, and performing preliminary screening of candidate grid connection locations. When the voltage support effect of the access point meets the conditions, the current parameters corresponding to the power flow transfer branch reflecting the power flow coupling degree between the AC line and the embedded DC system are calculated after fault blocking simulation, eliminating candidate grid connection locations that may lead to large-scale power flow transfer and overload of multiple AC lines, and further screening candidate grid connection locations. Finally, the multi-infeed interaction factor index and voltage-reactive power sensitivity index between the embedded DC system and the existing DC system in the target area grid are calculated to evaluate the voltage coupling characteristics between the embedded DC and the existing DC system. The candidate grid connection locations that finally meet the pre-set conditions for the multi-infeed interaction factor index and voltage-reactive power sensitivity index are determined as the target grid connection locations of the embedded DC system, eliminating candidate grid connection locations with a high degree of voltage coupling between DC systems. This application can provide a reference for the planning and operation of embedded DC, ensuring the safe and stable operation of AC and DC power grids.

[0110] Another embodiment of this application provides an embedded DC grid-connected location determination device based on system coupling characteristics, such as... Figure 5 As shown, it includes:

[0111] The first calculation module 1 is used to perform calculations based on the first structural parameters of the target area power grid and the embedded DC system to be connected to the grid, to obtain the voltage stiffness index of the embedded DC system at the candidate grid connection location.

[0112] The second calculation module 2 is used to perform fault blocking simulation on the embedded DC system when the voltage stiffness index meets the preset voltage stiffness constraint conditions. It performs calculation processing based on the second structural parameters and operating parameters of the power flow transfer branch before the fault blocking simulation to obtain the current parameters after the fault blocking simulation corresponding to the power flow transfer branch.

[0113] The third calculation module 3 is used to calculate the multi-feed interaction factor index and voltage-reactive power sensitivity index between the embedded DC system and the original DC system in the target area power grid when the current parameters meet the preset current constraint conditions corresponding to the power flow transfer branch.

[0114] The determination module 4 is used to determine the candidate grid connection location as the target grid connection location of the embedded DC system when the multi-feed interaction factor index and the voltage-reactive power sensitivity index meet preset conditions.

[0115] In the specific implementation process, the first calculation module 1 is specifically configured to: construct a Thevenin equivalent circuit containing the target regional power grid and the embedded DC system; perform calculation on the Thevenin equivalent circuit based on first structural parameters of the target regional power grid and the embedded DC system to be connected to the grid, to obtain a Thevenin equivalent potential of the target regional power grid at the candidate grid-connected position and a first Thevenin equivalent impedance; and perform calculation and processing based on the Thevenin equivalent potential, the first Thevenin equivalent impedance and a second equivalent impedance of the embedded DC system, to obtain a voltage stiffness index of the embedded DC system at the candidate grid-connected position.

[0116] In the specific implementation process, the second calculation module 2 is specifically configured to: when the voltage stiffness index is greater than or equal to a preset voltage stiffness threshold, perform fault locking simulation on the embedded DC system, to obtain a pre-fault current parameter of the candidate grid-connected position before the fault locking simulation; perform calculation and processing based on an admittance parameter of the power flow transfer branch and the current parameter, to obtain a power flow transfer factor corresponding to the power flow transfer branch; perform multiplication operation and processing based on the current parameter and the power flow transfer factor, to obtain a power flow transfer component corresponding to the power flow transfer branch; and perform addition operation and processing based on the power flow transfer component and the current parameter, to obtain a post-fault current parameter of the power flow transfer branch after the fault locking simulation.

[0117] In the specific implementation process, the third calculation module 3 is specifically configured to: when the current parameter is less than or equal to a maximum current value corresponding to the power flow transfer branch, perform calculation and processing based on voltage parameters of the original DC system and the embedded DC system, to obtain a multi-infeed interaction factor index; and perform evaluation on a reactive power and voltage micro-increase change of the embedded DC system at the candidate grid-connected position by using a voltage-reactive power sensitivity evaluation method, to obtain a voltage-reactive power sensitivity index.

[0118] In the specific implementation process, the third calculation module 3 is further configured to: obtain a first voltage parameter of the original DC system before the embedded DC system at the candidate grid-connected position, a second voltage parameter of the original DC system after the embedded DC system at the candidate grid-connected position and a third voltage parameter of the embedded DC system at the candidate grid-connected position; perform subtraction operation and processing based on the first voltage parameter and the second voltage parameter, to obtain a first difference value; perform absolute value calculation and processing on the first difference value, to obtain a voltage change amount; and perform calculation and processing based on the power source change amount, the third voltage parameter and a predetermined voltage drop parameter, to obtain the multi-infeed interaction factor index.

[0119] In the implementation process, the third calculation module 3 is further configured to: construct a power flow calculation correction equation; convert the correction equation to obtain a conversion equation under the condition that active power is unchanged; and solve the conversion equation based on first operation parameters of the embedded DC system before the candidate grid-connected position and second operation parameters of the embedded DC system after the candidate grid-connected position to obtain the voltage-reactive power sensitivity index of the embedded DC system at the candidate grid-connected position.

[0120] In the implementation process, the device further comprises a filtering module, which is specifically configured to: exclude the candidate grid-connected position when the voltage stiffness index does not satisfy a preset voltage stiffness constraint condition, or the current parameter does not satisfy a preset current constraint condition corresponding to the power flow transfer branch, or the multi-infeed interaction factor index and the voltage-reactive power sensitivity index do not satisfy a preset condition.

[0121] The application obtains the voltage support of the AC power grid on the embedded DC system by calculating the voltage stiffness of the preset embedded DC system access point, excludes the candidate grid-connected position that does not satisfy the voltage support, and preliminarily screens the candidate grid-connected position; when the voltage support of the access point satisfies the condition, the current parameter after fault blocking simulation corresponding to the power flow transfer branch reflecting the degree of power flow coupling between the AC line and the embedded DC system is calculated, the candidate grid-connected position that may cause large-scale power flow transfer and cause overload of the multi-loop AC line is excluded, and the candidate grid-connected position is further screened; finally, the multi-infeed interaction factor index and the voltage-reactive power sensitivity index between the embedded DC system and the original DC system in the target regional power grid are calculated, which are used to evaluate the voltage coupling characteristics between the embedded DC and the existing DC system, the candidate grid-connected position that finally satisfies the preset condition of the multi-infeed interaction factor index and the voltage-reactive power sensitivity index is determined as the target grid-connected position of the embedded DC system, and the candidate grid-connected position with high voltage coupling degree between DC systems is excluded. The application can provide a reference for the planning and operation of the embedded DC, and guarantee the safe and stable operation of the AC / DC power grid.

[0122] Another embodiment of the application provides a storage medium storing a computer program, which is executed by a processor to implement the following method steps:

[0123] Step one, based on the first structure parameters of the target regional power grid and the embedded DC system to be grid-connected, the voltage stiffness index of the embedded DC system at the candidate grid-connected position is obtained through calculation and processing;

[0124] Step two, when the voltage stiffness index meets the preset voltage stiffness constraint condition, fault blocking simulation is performed on the embedded DC system, and the current parameters corresponding to the fault blocking simulation after the second structural parameters and the operating parameters of the power flow transfer branch before the fault blocking simulation are calculated and processed.

[0125] Step three, when the current parameters meet the preset current constraint condition corresponding to the power flow transfer branch, the multi-infeed interaction factor index and the voltage-reactive power sensitivity index between the embedded DC system and the original DC system in the target regional power grid are calculated.

[0126] Step four, when the multi-infeed interaction factor index and the voltage-reactive power sensitivity index meet the preset condition, the candidate grid-connected position is determined as the target grid-connected position of the embedded DC system.

[0127] A person of ordinary skill in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer readable storage medium. When the computer program is executed, it can include the processes of the above-mentioned embodiments. Any reference to memory, storage, database or other medium used in the embodiments provided in the present 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. As an illustration but not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), 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) and the like.

[0128] Those skilled in the art can clearly understand that, for the convenience and brevity of description, only the division of the above-mentioned functional units and modules is exemplified. In actual application, the above-mentioned functions can be completed by different functional units and modules according to needs, that is, the internal structure of the device is divided into different functional units or modules to complete all or part of the functions described above.

[0129] The specific implementation process of the above method steps can refer to the above-mentioned embodiments of the embedded direct current grid-connected position determination method based on system coupling characteristics, which will not be repeated here.

[0130] The application obtains the voltage support of the alternating current power grid to the embedded direct current system by calculating the voltage stiffness of the preset embedded direct current transmission system access point, excludes the candidate grid-connected positions that do not meet the voltage support, and preliminarily screens the candidate grid-connected positions; when the voltage support of the access point meets the condition, the current parameters after fault blocking simulation of the power flow transfer branch corresponding to the coupling degree of the power flow of the alternating current line and the embedded direct current system are calculated, the candidate grid-connected positions that may cause large-scale power flow transfer and cause overload of the multi-loop alternating current line are excluded, and the candidate grid-connected positions are further screened; finally, the multi-infeed interaction factor index and the voltage-reactive power sensitivity index between the embedded direct current system and the original direct current system in the target regional power grid are calculated, which are used to evaluate the voltage coupling characteristics between the embedded direct current and the existing direct current system, the candidate grid-connected positions that finally meet the preset conditions of the multi-infeed interaction factor index and the voltage-reactive power sensitivity index are determined as the target grid-connected position of the embedded direct current system, and the candidate grid-connected positions with high voltage coupling degree between direct current systems are excluded. The application can provide a reference for the planning and operation of embedded direct current, and guarantee the safe and stable operation of the alternating current and direct current power grid.

[0131] Another embodiment of the application provides an electronic device, which can be a server. The electronic device includes a processor, a memory, a network interface and a database connected by a system bus. The processor of the electronic device is used to provide computing and control capabilities. The memory of the electronic device includes non-volatile and / or volatile storage media, internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The network interface of the electronic device is used to communicate with the external client through the network connection. The electronic device program is executed by the processor to realize the function or step of the server side of the embedded direct current grid-connected position determination method based on system coupling characteristics.

[0132] In one embodiment, an electronic device, which can be a client, is provided. The electronic device includes a processor, a memory, a network interface, a display screen and an input device connected through a system bus. Among them, the processor of the electronic device is used to provide computing and control capabilities. The memory of the electronic device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operating system and the computer program in the non-volatile storage medium to run. The network interface of the electronic device is used to communicate with an external server through a network connection. The electronic device program is executed by the processor to implement the functions or steps of a client side of an embedded DC grid-connected position determination method based on system coupling characteristics.

[0133] Another embodiment of the present application provides an electronic device, at least including a memory and a processor, the memory stores a computer program, and the processor implements the following method steps when executing the computer program on the memory:

[0134] Step one, based on the first structural parameters of the target regional power grid and the embedded DC system to be connected to the grid, the voltage stiffness index of the embedded DC system at the candidate grid-connected position is obtained through calculation and processing;

[0135] Step two, when the voltage stiffness index meets the preset voltage stiffness constraint condition, the embedded DC system is simulated for fault blocking, and based on the second structural parameters and operating parameters of the power flow transfer branch before fault blocking simulation, the current parameters corresponding to the fault blocking simulation after the power flow transfer branch are obtained through calculation and processing;

[0136] Step three, when the current parameter meets the preset current constraint condition corresponding to the power flow transfer branch, the multi-infeed interaction factor index and the voltage-reactive power sensitivity index between the embedded DC system and the original DC system in the target regional power grid are calculated;

[0137] Step four, when the multi-infeed interaction factor index and the voltage-reactive power sensitivity index meet the preset condition, the candidate grid-connected position is determined as the target grid-connected position of the embedded DC system.

[0138] The specific implementation process of the above method steps can be referred to the above-mentioned embodiment of the embedded DC grid-connected position determination method based on system coupling characteristics, which will not be repeated here.

[0139] The application obtains the voltage support of the alternating current power grid on the embedded direct current system through the calculation of the voltage stiffness of the preset embedded direct current system access point, excludes the candidate grid-connected positions that do not meet the voltage support, and preliminarily screens the candidate grid-connected positions; when the voltage support of the access point meets the condition, the current parameters after fault blocking simulation corresponding to the power flow transfer branch reflecting the power flow coupling degree of the alternating current line and the embedded direct current system are calculated, the candidate grid-connected positions that may cause large-scale power flow transfer and cause the overload of the multi-loop alternating current line are excluded, and the candidate grid-connected positions are further screened; finally, the multi-infeed interaction factor index and the voltage-reactive power sensitivity index between the embedded direct current system and the original direct current system in the target regional power grid are calculated, which are used for evaluating the voltage coupling characteristics between the embedded direct current and the existing direct current system, the candidate grid-connected positions that finally meet the preset conditions of the multi-infeed interaction factor index and the voltage-reactive power sensitivity index are determined as the target grid-connected positions of the embedded direct current system, and the candidate grid-connected positions with high voltage coupling degree between direct current systems are excluded, so that the application can provide a reference for the planning and operation of the embedded direct current, and guarantee the safe and stable operation of the alternating current and direct current power grid.

[0140] The above embodiments are only exemplary embodiments of the application and are not used to limit the application, and the protection scope of the application is defined by the claims. Those skilled in the art can make various modifications or equivalent replacements to the application within the spirit and protection scope of the application, and the modification or equivalent replacement is also regarded as falling within the protection scope of the application.

Claims

1. An embedded DC grid-connected location determination method based on system coupling characteristics, characterized in that, include: The voltage stiffness index of the embedded DC system at the candidate grid connection location is obtained by performing calculations based on the first structural parameters of the target area power grid and the embedded DC system to be connected to the grid. When the voltage stiffness index meets the preset voltage stiffness constraint condition, the embedded DC system is subjected to fault blocking simulation. The second structural parameters and operating parameters of the power flow transfer branch before the fault blocking simulation are calculated and processed to obtain the current parameters after the fault blocking simulation corresponding to the power flow transfer branch. When the current parameters satisfy the preset current constraint conditions corresponding to the power flow transfer branch, calculate the multi-feed interaction factor index and voltage-reactive power sensitivity index between the embedded DC system and the original DC system in the target area power grid. When the multi-feed interaction factor index and the voltage-reactive power sensitivity index meet the preset conditions, the candidate grid connection location is determined as the target grid connection location of the embedded DC system. When the current parameters satisfy the preset current constraint conditions corresponding to the power flow transfer branch, the multi-infeed interaction factor and voltage-reactive power sensitivity index between the embedded DC system and the original DC system in the target area power grid are calculated, specifically including: When the current parameter is less than or equal to the maximum current value corresponding to the power flow transfer branch, the multi-feed interaction factor index is obtained by calculating based on the voltage parameters of the original DC system and the embedded DC system. The voltage-reactive power sensitivity evaluation method is used to evaluate the small changes in reactive power and voltage at the candidate grid connection location of the embedded DC system, and the voltage-reactive power sensitivity index is obtained.

2. The method as described in claim 1, characterized in that, The calculation and processing based on the first structural parameters of the target area power grid and the embedded DC system to be connected to the grid yields the voltage stiffness index of the embedded DC system at the candidate grid connection location, specifically including: Construct a Thevenin equivalent circuit that includes the target area power grid and the embedded DC system; The Thevenin equivalent circuit is calculated based on the first structural parameters of the target area power grid and the embedded DC system to be connected to the grid, so as to obtain the Thevenin equivalent potential and the first Thevenin equivalent impedance of the target area power grid at the candidate grid connection location. The voltage stiffness index of the embedded DC system at the candidate grid connection location is obtained by calculation based on the Thevenin equivalent potential, the first Thevenin equivalent impedance, and the second equivalent impedance of the embedded DC system.

3. The method as described in claim 1, characterized in that, When the voltage stiffness index meets the preset voltage stiffness constraint condition, a fault blocking simulation is performed on the embedded DC system. Based on the second structural parameters and operating parameters of the power flow transfer branch before the fault blocking simulation, calculations are performed to obtain the current parameters corresponding to the power flow transfer branch after the fault blocking simulation, specifically including: When the voltage stiffness index is greater than or equal to the preset voltage stiffness threshold, the embedded DC system is subjected to fault blocking simulation to obtain the pre-fault current parameters of the candidate grid connection position before the fault blocking simulation. The power flow transfer factor corresponding to the power flow transfer branch is obtained by calculation based on the admittance parameter and the current parameter of the power flow transfer branch. Based on the current parameters and the power flow transfer factor, a multiplication operation is performed to obtain the power flow transfer component corresponding to the power flow transfer branch. Based on the power flow transfer component and the current parameter, an addition operation is performed to obtain the current parameter of the power flow transfer branch after the fault blocking simulation.

4. The method as described in claim 1, characterized in that, The calculation and processing based on the voltage parameters of the original DC system and the embedded DC system yields a multi-feed interaction factor index, which specifically includes: The embedded DC system acquires the first voltage parameter of the original DC system before the candidate grid connection location, the second voltage parameter of the original DC system after the candidate grid connection location, and the third voltage parameter of the embedded DC system at the candidate grid connection location. A subtraction operation is performed based on the first voltage parameter and the second voltage parameter to obtain the first difference; The absolute value of the first difference is calculated to obtain the voltage change. The multi-feed interaction factor index is obtained by calculating based on the voltage change, the third voltage parameter, and the predetermined voltage drop parameter.

5. The method as described in claim 1, characterized in that, The voltage-reactive power sensitivity assessment method is used to evaluate the reactive power and voltage micro-increase changes of the embedded DC system at the candidate grid connection location, and the voltage-reactive power sensitivity index is obtained, specifically including: Construct power flow calculation correction equations; The modified equation is transformed while keeping the active power constant, to obtain the transformed equation; The conversion equation is solved based on the first operating parameters of the embedded DC system before the candidate grid connection location and the second operating parameters of the embedded DC system after the candidate grid connection location to obtain the voltage-reactive power sensitivity index of the embedded DC system at the candidate grid connection location.

6. The method as described in claim 1, characterized in that, The method further includes: When the voltage stiffness index does not meet the preset voltage stiffness constraint condition, or the current parameter does not meet the preset current constraint condition corresponding to the power flow transfer branch, or the multi-feed interaction factor index and the voltage-reactive power sensitivity index do not meet the preset conditions, the candidate grid connection location is excluded.

7. An embedded DC grid-connected location determination device based on system coupling characteristics, characterized in that, include: The first calculation module is used to perform calculations based on the first structural parameters of the target area power grid and the embedded DC system to be connected to the grid, to obtain the voltage stiffness index of the embedded DC system at the candidate grid connection location. The second calculation module is used to perform fault blocking simulation on the embedded DC system when the voltage stiffness index meets the preset voltage stiffness constraint conditions. It performs calculations based on the second structural parameters and operating parameters of the power flow transfer branch before the fault blocking simulation to obtain the current parameters after the fault blocking simulation corresponding to the power flow transfer branch. The third calculation module is used to calculate the multi-infeed interaction factor index and voltage-reactive power sensitivity index between the embedded DC system and the original DC system in the target area power grid when the current parameter meets the preset current constraint condition corresponding to the power flow transfer branch. Specifically, it includes: when the current parameter is less than or equal to the maximum current value corresponding to the power flow transfer branch, performing calculation processing based on the voltage parameters of the original DC system and the embedded DC system to obtain the multi-infeed interaction factor index; and using the voltage-reactive power sensitivity evaluation method to evaluate the reactive power and voltage micro-increase changes of the embedded DC system at the candidate grid connection location to obtain the voltage-reactive power sensitivity index. The determination module is used to determine the candidate grid connection location as the target grid connection location of the embedded DC system when the multi-feed interaction factor index and the voltage-reactive power sensitivity index meet preset conditions.

8. A storage medium, characterized in that, The storage medium stores a computer program, which, when executed by a processor, implements the steps of the embedded DC grid-connected location determination method based on system coupling characteristics as described in any one of claims 1-6.

9. An electronic device, characterized in that, It includes at least a memory and a processor, wherein the memory stores a computer program, and the processor, when executing the computer program in the memory, implements the steps of the embedded DC grid-connected location determination method based on system coupling characteristics as described in any one of claims 1-6.

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