Method and device for characterizing grid coupling characteristics, storage medium, and computer device

Abstract

The present application discloses a method and device for characterizing grid coupling characteristics, a storage medium, and a computer device, which are applied to a receiving-end power grid. The method includes: obtaining a plurality of power-receiving nodes in the receiving-end power grid, where the energy of the power-receiving nodes is DC energy or new energy, and the new energy includes wind power generation energy and photovoltaic power generation energy; selecting any power-receiving node with DC energy as the energy, and any power-receiving node with new energy as the energy, and obtaining the reactive voltage coupling characteristics between the selected power-receiving nodes according to the reactive voltage dynamic characteristics of the DC energy and the reactive voltage dynamic characteristics of the new energy; calculating the coupling degree value between the power-receiving nodes based on the reactive voltage coupling characteristics between the selected power-receiving nodes, and determining the characterization result of the coupling characteristics between the selected power-receiving nodes based on the comparison between the coupling degree value between the power-receiving nodes and a preset coupling degree threshold, so as to realize the characterization of the coupling degree of DC and new energy across voltage levels.

Description

Technical Field

[0001] The present application relates to the technical field of power systems, and particularly to a method and device for characterizing grid coupling characteristics, a storage medium, and a computer device. Background Art

[0002] With the change of the new power system form, some receiving-end power grids have the characteristics of multi-circuit DC feeding, increasing proportion of new energy and decreasing proportion of conventional power sources in the receiving-end power grid, showing strong power electronics characteristics. Compared with the voltage dynamic characteristics of conventional power sources, the external characteristics of power electronic devices depend on the external characteristics of converters and are closely related to controllers. If the DC feeding ratio increases, the start-up and standby of conventional power sources in the receiving-end power grid are insufficient and the reactive power support capacity of new energy is limited, which may increase the risk of transient voltage instability in the receiving-end power grid. Summary of the Invention

[0003] In view of this, the present application provides a method and device for characterizing grid coupling characteristics, a storage medium, and a computer device, which are applied to a receiving-end power grid. Multiple power receiving nodes in the receiving-end power grid are obtained, where the energy of the power receiving nodes is DC energy or new energy, and the new energy includes wind power generation energy and photovoltaic power generation energy; any power receiving node with DC energy as the energy and any power receiving node with new energy as the energy are selected, and according to the reactive power-voltage dynamic characteristics of DC energy and the reactive power-voltage dynamic characteristics of new energy, the reactive power-voltage coupling characteristics between the selected power receiving nodes are obtained; based on the reactive power-voltage coupling characteristics between the selected power receiving nodes, the coupling degree value between the power receiving nodes is calculated, and based on the comparison between the coupling degree value between the power receiving nodes and a preset coupling degree threshold, the coupling characteristic characterization result between the selected power receiving nodes is determined, which can realize the characterization of the coupling degree of DC and new energy across voltage levels.

[0004] According to one aspect of the present application, a method for characterizing grid coupling characteristics is provided, which is applied to a receiving-end power grid; the method includes:

[0005] Obtain multiple power receiving nodes in the receiving-end power grid, where the energy of the power receiving nodes is DC energy or new energy, and the new energy includes wind power generation energy and photovoltaic power generation energy;

[0006] Select any power receiving node with DC energy as the energy and any power receiving node with new energy as the energy, and according to the reactive power-voltage dynamic characteristics of DC energy and the reactive power-voltage dynamic characteristics of new energy, obtain the reactive power-voltage coupling characteristics between the selected power receiving nodes;

[0007] Based on the reactive power-voltage coupling characteristics between the selected power receiving nodes, calculate the coupling degree value between the power receiving nodes, and based on the comparison between the coupling degree value between the power receiving nodes and a preset coupling degree threshold, determine the coupling characteristic characterization result between the selected power receiving nodes.

[0008] Optionally, calculating the coupling degree value between the receiving power nodes based on the reactive voltage coupling characteristics between the selected receiving power nodes includes:

[0009] Obtaining the voltage amplitude change conditions of the selected receiving power nodes;

[0010] Calculating the coupling degree value between the receiving power nodes based on the coupling degree value calculation formula between the receiving power nodes and the voltage amplitude change conditions of each selected receiving power node, where the coupling degree value calculation formula between the receiving power nodes is:

[0011]

[0012] D ij represents the coupling degree value between receiving power node i and receiving power node j, and α ij represents the voltage amplitude change of receiving power node i when the voltage amplitude change of receiving power node j is ΔU j , and α ji represents the voltage amplitude change of receiving power node j when the voltage amplitude change of receiving power node i is ΔU i .

[0013] Optionally, obtaining the voltage amplitude change conditions of the selected receiving power nodes includes:

[0014] Obtaining the reactive power increments of each selected receiving power node;

[0015] Calculating the voltage amplitude change conditions of the selected receiving power nodes based on the voltage amplitude change calculation formula and the reactive power increments of each selected receiving power node, where the voltage amplitude change calculation formula is:

[0016]

[0017] α ij represents the voltage amplitude change of receiving power node i when the voltage amplitude change of receiving power node j is ΔU j , and α ji represents the voltage amplitude change of receiving power node j when the voltage amplitude change of receiving power node i is ΔU i , μ i,j represents the voltage influence degree of receiving power node i on receiving power node j, and respectively represent the reactive voltage coefficients of receiving power nodes i and j, and ΔQ i and ΔQ j respectively represent the reactive power increments of receiving power nodes i and j.

[0018] Optionally, obtaining the reactive power increments of each selected receiving power node includes:

[0019] Calculate the reactive power increment of each selected power receiving node based on the reactive power increment calculation formula, where the reactive power increment calculation formula is:

[0020]

[0021] ΔQ i represents the reactive power increment of power receiving node i, and respectively represent the reactive power-voltage sensitivities of node i, node j, and the commutation bus node k of the DC converter station, ΔU i represents the change in voltage amplitude of power receiving node i, μ i,j represents the voltage influence degree of power receiving node i on power receiving node j, μ i,k represents the voltage influence degree of power receiving node i on the commutation bus node k of the converter station.

[0022] Optionally, before calculating the reactive power increment of each selected power receiving node based on the reactive power increment calculation formula, the method further includes:

[0023] Calculate the voltage influence degree between power receiving nodes based on the first voltage influence degree calculation formula, and calculate the voltage influence degree between the power receiving node and the commutation bus node of the converter station based on the second voltage influence degree calculation formula, where the first voltage influence degree calculation formula is:

[0024]

[0025] The second voltage influence degree calculation formula is:

[0026]

[0027] μ i,j represents the voltage influence degree of power receiving node i on power receiving node j, μ i,k represents the voltage influence degree of power receiving node i on the commutation bus node k of the converter station, ΔQ i represents the reactive power increment of power receiving node i, ΔQ i,j and ΔQ i,k respectively represent the reactive power increment flowing from power receiving node i to power receiving node j and power receiving node k.

[0028] Optionally, the coupling degree value between the power receiving nodes characterizes the critical coupling degree between the DC energy and the new energy under different voltage levels with the trigger of the new energy high-voltage or low-voltage ride-through as the critical condition.

[0029] Optionally, determining the coupling characteristic representation result between the selected power receiving nodes based on the comparison between the coupling degree value between the power receiving nodes and the preset coupling degree threshold includes:

[0030] When the coupling degree value between the power receiving nodes is greater than or equal to the preset coupling degree threshold, the characterization result of the coupling characteristics between the selected power receiving nodes is that there is a coupling relationship;

[0031] When the coupling degree value between the power receiving nodes is less than the preset coupling degree threshold, the characterization result of the coupling characteristics between the selected power receiving nodes is that there is no coupling relationship.

[0032] According to another aspect of the present application, there is provided a device for characterizing the coupling characteristics of a power grid, which is applied to the receiving-end power grid; the device includes:

[0033] A power receiving node acquisition module, configured to acquire a plurality of power receiving nodes in the receiving-end power grid, wherein the energy of the power receiving nodes is DC energy or new energy, and the new energy includes wind power generation energy and photovoltaic power generation energy;

[0034] A coupling characteristic acquisition module, configured to select any power receiving node with DC energy and any power receiving node with new energy, and acquire the reactive voltage coupling characteristics between the selected power receiving nodes according to the reactive voltage dynamic characteristics of the DC energy and the reactive voltage dynamic characteristics of the new energy;

[0035] A coupling characteristic characterization module, configured to calculate the coupling degree value between the power receiving nodes based on the reactive voltage coupling characteristics between the selected power receiving nodes, and determine the characterization result of the coupling characteristics between the selected power receiving nodes based on the comparison between the coupling degree value between the power receiving nodes and the preset coupling degree threshold.

[0036] Optionally, the coupling characteristic characterization module is further configured to:

[0037] Obtain the voltage amplitude change situation of the selected power receiving nodes;

[0038] Based on the coupling degree value calculation formula between the power receiving nodes and the voltage amplitude change situation of each selected power receiving node, calculate the coupling degree value between the power receiving nodes, where the coupling degree value calculation formula between the power receiving nodes is:

[0039]

[0040] D ij represents the coupling degree value between power receiving node i and power receiving node j, and α ij represents that when the voltage amplitude change of power receiving node j is ΔU j the voltage amplitude change of power receiving node i, and α ji represents that when the voltage amplitude change of power receiving node i is ΔU i the voltage amplitude change of power receiving node j.

[0041] Optionally, the coupling characteristic acquisition module is further configured to:

[0042] Obtain the reactive power increments of the selected power-receiving nodes;

[0043] Based on the voltage amplitude change calculation formula and the reactive power increments of the selected power-receiving nodes, calculate the voltage amplitude change conditions of the selected power-receiving nodes, where the voltage amplitude change calculation formula is:

[0044]

[0045] α ij represents the voltage amplitude change of the power-receiving node j as ΔU j when the voltage amplitude change of the power-receiving node i is α ji represents the voltage amplitude change of the power-receiving node i as ΔU i when the voltage amplitude change of the power-receiving node j is μ i,j represents the voltage influence degree of the power-receiving node i on the power-receiving node j, and respectively represent the reactive power-voltage coefficients of the power-receiving nodes i and j, ΔQ i and ΔQ j respectively represent the reactive power increments of the power-receiving nodes i and j.

[0046] Optionally, the coupling characteristic acquisition module is further configured to:

[0047] Based on the reactive power increment calculation formula, calculate the reactive power increments of the selected power-receiving nodes, where the reactive power increment calculation formula is:

[0048]

[0049] ΔQ i represents the reactive power increment of the power-receiving node i, and respectively represent the reactive power-voltage sensitivities of the nodes i, j and the commutation bus node k of the DC converter station, ΔU i represents the voltage amplitude change of the power-receiving node i, μ i,j represents the voltage influence degree of the power-receiving node i on the power-receiving node j, μ i,k represents the voltage influence degree of the power-receiving node i on the commutation bus node k of the converter station.

[0050] Optionally, the coupling characteristic acquisition module is further configured to:

[0051] Based on the first voltage influence degree calculation formula, calculate the voltage influence degrees between the power-receiving nodes, and based on the second voltage influence degree calculation formula, calculate the voltage influence degrees between the power-receiving nodes and the commutation bus nodes of the converter station, where the first voltage influence degree calculation formula is:

[0052]

[0053] The calculation formula for the second voltage influence degree is as follows:

[0054]

[0055] μ i,j represents the voltage influence degree of the power receiving node i on the power receiving node j, and μ i,k represents the voltage influence degree of the power receiving node i on the converter bus node k of the converter station, and ΔQ i represents the reactive power increment of the power receiving node i, and ΔQ i,j and ΔQ i,k respectively represent the reactive power increment flowing from the power receiving node i to the power receiving node j and the power receiving node k.

[0056] Optionally, the coupling degree value between the power receiving nodes characterizes the critical coupling degree between the DC energy and the new energy under different voltage levels with the trigger of the new energy high-voltage or low-voltage crossing as the critical condition.

[0057] Optionally, the coupling characteristic characterization module is further configured to:

[0058] When the coupling degree value between the power receiving nodes is greater than or equal to the preset coupling degree threshold, the coupling characteristic characterization result between the selected power receiving nodes is that there is a coupling relationship;

[0059] When the coupling degree value between the power receiving nodes is less than the preset coupling degree threshold, the coupling characteristic characterization result between the selected power receiving nodes is that there is no coupling relationship.

[0060] According to another aspect of the present application, there is provided a storage medium on which a computer program is stored, and when the program is executed by a processor, the above-mentioned power grid coupling characteristic characterization method is implemented.

[0061] According to still another aspect of the present application, there is provided a computer device, including a storage medium, a processor, and a computer program stored on the storage medium and executable on the processor. When the processor executes the program, the above-mentioned power grid coupling characteristic characterization method is implemented.

[0062] With the above technical solution, a method and device for characterizing the grid coupling characteristics, a storage medium, and a computer device provided by the present application are applied to the receiving-end grid. Multiple power-receiving nodes in the receiving-end grid are obtained, where the energy of the power-receiving nodes is DC energy or new energy, and the new energy includes wind power generation energy and photovoltaic power generation energy. Any power-receiving node with DC energy as the energy and any power-receiving node with new energy as the energy are selected. According to the reactive power-voltage dynamic characteristics of DC energy and the reactive power-voltage dynamic characteristics of new energy, the reactive power-voltage coupling characteristics between the selected power-receiving nodes are obtained. Based on the reactive power-voltage coupling characteristics between the selected power-receiving nodes, the coupling degree value between the power-receiving nodes is calculated. Based on the comparison between the coupling degree value between the power-receiving nodes and a preset coupling degree threshold, the coupling characteristic characterization result between the selected power-receiving nodes is determined, and the characterization of the coupling degree of DC and new energy across voltage levels can be realized.

[0063] The above description is only an overview of the technical solution of the present application. In order to be able to understand the technical means of the present application more clearly, it can be implemented according to the content of the specification. And in order to make the above and other purposes, features, and advantages of the present application more obvious and understandable, the specific embodiments of the present application are specifically given below. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The schematic embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation to the present application. In the drawings:

[0065] Figure 1 A flowchart showing a method for characterizing the grid coupling characteristics provided by an embodiment of the present application is shown;

[0066] Figure 2 A system diagram of grid nodes provided by an embodiment of the present application is shown;

[0067] Figure 3 A flowchart showing another method for characterizing the grid coupling characteristics provided by an embodiment of the present application is shown;

[0068] Figure 4 A schematic diagram of power balance of an inverter station in a DC system provided by an embodiment of the present application is shown;

[0069] Figure 5 A flowchart showing a method for calculating the DC control system equation provided by an embodiment of the present application is shown;

[0070] Figure 6 A system diagram under the coupling of high-voltage DC and new energy across voltage levels provided by an embodiment of the present application is shown;

[0071] Figure 7Shows a schematic diagram of the relationship between a DC node and a new energy node provided by an embodiment of the present application and the voltage drop situation of the new energy node;

[0072] Figure 8 Shows a schematic diagram of the relationship between a DC node and a new energy node provided by an embodiment of the present application and the voltage rise situation of the new energy node;

[0073] Figure 9 Shows a schematic structural diagram of a grid coupling characteristic characterization device provided by an embodiment of the present application. Detailed implementation manners

[0074] The present application will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments. It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other.

[0075] In this embodiment, a method for characterizing grid coupling characteristics is provided. As Figure 1 shown, it is applied to a receiving-end power grid, and the method includes:

[0076] Step 101: Obtain multiple power receiving nodes in the receiving-end power grid, where the energy of the power receiving nodes is DC energy or new energy, and the new energy includes wind power generation energy and photovoltaic power generation energy.

[0077] In the above embodiment of the present application, under the coupling of DC and new energy across voltage levels, based on the reactive voltage sensitivity, a method for characterizing the reactive coupling degree of DC and new energy is proposed, that is, first analyze the reactive voltage dynamic characteristics of the DC transmission system under different grid faults, then analyze the reactive voltage dynamic characteristics of wind farms and photovoltaic power generation under different grid faults respectively, and finally, based on the voltage reactive sensitivity, analyze the reactive voltage coupling characteristics when DC and new energy are connected across voltage levels. Specifically, as Figure 2 shown, obtain multiple power receiving nodes in the receiving-end power grid ( Figure 2 with serial numbers 1 to 38), and the energy of the power receiving nodes is DC energy or new energy, and the new energy includes wind power generation energy and photovoltaic power generation energy.

[0078] Step 102: Select any power receiving node with DC energy as the energy source and any power receiving node with new energy as the energy source, and obtain the reactive voltage coupling characteristics between the selected power receiving nodes according to the reactive voltage dynamic characteristics of the DC energy and the reactive voltage dynamic characteristics of the new energy.

[0079] Step 103: Based on the reactive voltage coupling characteristics between the selected power receiving nodes, calculate the coupling degree value between the power receiving nodes, and determine the characterization result of the coupling characteristics between the selected power receiving nodes based on the comparison between the coupling degree value between the power receiving nodes and a preset coupling degree threshold.

[0080] Next, select any receiving node with DC energy as the power source and any receiving node with new energy as the power source. According to the reactive voltage dynamic characteristics of DC energy and the reactive voltage dynamic characteristics of new energy, obtain the reactive voltage coupling characteristics between the selected receiving nodes. Based on the reactive voltage coupling characteristics between the selected receiving nodes, calculate the coupling degree value between the receiving nodes. Based on the comparison between the coupling degree value between the receiving nodes and the preset coupling degree threshold, determine the characterization result of the coupling characteristics between the selected receiving nodes. In this way, the influence degree of the DC system and new energy across voltage levels can be effectively evaluated.

[0081] By applying the technical solution of this embodiment, multiple receiving nodes in the receiving-end power grid are obtained. Select any receiving node with DC energy as the power source and any receiving node with new energy as the power source. According to the reactive voltage dynamic characteristics of DC energy and the reactive voltage dynamic characteristics of new energy, obtain the reactive voltage coupling characteristics between the selected receiving nodes. Based on the reactive voltage coupling characteristics between the selected receiving nodes, calculate the coupling degree value between the receiving nodes. Based on the comparison between the coupling degree value between the receiving nodes and the preset coupling degree threshold, determine the characterization result of the coupling characteristics between the selected receiving nodes. It is possible to characterize the coupling degree of DC and new energy across voltage levels on the basis of analyzing the influence of the coupling of DC and new energy on the transient voltage stability of the power grid system.

[0082] Further, as a refinement and extension of the specific implementation manner of the above embodiment, in order to fully illustrate the specific implementation process of this embodiment, another method for characterizing the grid coupling characteristics is provided, which is applied to the receiving-end power grid, as Figure 3 shown, and this method includes:

[0083] Step 201: Obtain multiple receiving nodes in the receiving-end power grid, where the energy of the receiving nodes is DC energy or new energy, and the new energy includes wind power generation energy and photovoltaic power generation energy.

[0084] Step 202: Select any receiving node with DC energy as the power source and any receiving node with new energy as the power source. According to the reactive voltage dynamic characteristics of DC energy and the reactive voltage dynamic characteristics of new energy, obtain the reactive voltage coupling characteristics between the selected receiving nodes.

[0085] In the above embodiment of the present application, multiple receiving nodes in the receiving-end power grid are obtained. Select any receiving node with DC energy as the power source and any receiving node with new energy as the power source. According to the reactive voltage dynamic characteristics of DC energy and the reactive voltage dynamic characteristics of new energy, obtain the reactive voltage coupling characteristics between the selected receiving nodes. Specifically:

[0086] First, deduce the reactive voltage characteristics of the inverter side of the DC transmission system, as Figure 4 shown,Figure 4 It is a schematic diagram of power balance for the inverter station of a DC system. U d is the DC voltage on the inverter side; I d is the DC current; P d is the DC active power; Q d is the reactive power consumed by the converter (including the converter transformer), i.e., the converter reactive power; U ac is the converter bus voltage; Q c is the reactive power of the filter, i.e., the compensating reactive power, B c is the filter susceptance; Q a is the reactive power exchanged between the DC and the system.

[0087] The algebraic equation for the reactive power exchanged between the DC receiving end and the system is:

[0088]

[0089] U dr -U d =R d I d ,

[0090] P d =2U d I d ,

[0091]

[0092] Q a =Q d -Q c ,

[0093] U d0 is the no-load DC voltage on the inverter side; N is the number of 6-pulse converters per pole; T is the turns ratio of the converter transformer; γ is the extinction angle on the inverter side; X c is the commutation reactance; is the power factor angle; U dr is the DC voltage on the rectifier side; R d is the DC line resistance; α is the firing angle on the rectifier side; μ is the commutation overlap angle.

[0094] Since a short circuit in the receiving-end AC system is likely to cause DC commutation failure and even lead to DC blocking, the reactive power-voltage dynamic characteristics on the inverter side of the DC system are closely related to the converter bus voltage and the external characteristics of its converters.

[0095] In particular, since the DC control system equations are very complex and there are many nonlinear links such as amplitude limiting, it is difficult to directly calculate using theoretical analytical methods. Generally, numerical integration methods need to be used and with the aid of power system simulation software for solution. The algorithm flow is shown, for example Figure 5 as follows.

[0096] After new energy is connected to the grid, the relationship between the voltage at the grid connection point and the grid voltage is as follows:

[0097]

[0098] is the voltage at the grid connection point; is the voltage at the grid cluster point; is the voltage drop on the transmission line; ΔU is the transverse voltage drop; δU is the longitudinal voltage drop.

[0099] For high-voltage long-distance transmission lines, the transverse component δU of the voltage drop is very small and can be ignored. Therefore, the amplitude of the voltage at the grid connection point can be approximately expressed as:

[0100]

[0101] R g +jX g is the impedance of the long-distance transmission line; P PCC and Q PCC are the active and reactive powers output by the new energy power station respectively.

[0102] When the grid voltage U S is constant and the line parameters have been determined, the voltage at the grid connection point depends on the output power of the new energy power station.

[0103] When the reactive power margin of the new energy power station is sufficient, by adjusting its reactive power output, the stability of the voltage at the grid connection point can be maintained. When the reactive power output of the new energy power station is constant, it can be simplified as:

[0104]

[0105] Among them,

[0106]

[0107] The grid voltage U S is affected by the output power of the new energy power station and the voltage U PCC at the grid connection point. When the reactive power margin of the new energy power station is sufficient, by adjusting its reactive power Q PCC to increase the voltage U PCC at the grid connection point, the adjustment of the grid voltage U S can be achieved.

[0108] Next, analyze the reactive voltage dynamic characteristics of the wind farm during high / low voltage ride-through. When the grid voltage drops, the incremental dynamic reactive current injected by the wind turbine should respond to the change in the voltage at the grid connection point and should satisfy:

[0109] ΔI W= K1×(0.9 - U PCC )×I WN (0.2 ≤ U PCC ≤ 0.9, 1.5 ≤ K1 ≤ 3),

[0110] ΔI w is the increment of dynamic reactive current injected into the wind farm, with the unit of ampere (A); K1 is the proportionality coefficient of dynamic reactive current of the wind farm, and the value range of K1 should be not less than 1.5 and not greater than 3; U PCC is the per-unit value of the grid connection point voltage of the wind farm, with the unit of per-unit value (pu); I WN is the rated current of the wind farm, with the unit of ampere (A).

[0111] When the grid voltage rises, the increment of dynamic reactive current absorbed by the fan should respond to the change of the grid connection point voltage and should satisfy:

[0112] ΔI W = K2×(U PCC - 1.1)×I WN (1.1 ≤ U PCC ≤ 1.3, K2 > 1.5),

[0113] ΔI w is the increment of dynamic reactive current absorbed by the wind farm, with the unit of ampere (A); K2 is the proportionality coefficient of dynamic reactive current of the wind farm, and the value range of K2 should be greater than 1.5; U PCC is the per-unit value of the grid connection point voltage of the wind farm; I WN is the rated current of the wind farm, with the unit of ampere (A).

[0114] Therefore, when the system fault causes the fan to enter the low voltage ride through, the low voltage ride through characteristics of the fan will make the wind farm become a "reactive power source", increasing the voltage of the fan side and the converter bus; when the wind farm enters the high voltage ride through, the high voltage ride through characteristics of the wind farm will make the wind farm become a "reactive power load", reducing the voltage of the fan side and the converter bus.

[0115] Similarly, the photovoltaic power station has reactive voltage dynamic characteristics, and the dynamic reactive current output by the inverter should track the change of the grid connection point voltage in real time and should satisfy:

[0116]

[0117] I pv_Q is the effective value of the dynamic reactive current output by the inverter; K3 and K4 are the proportional values of the dynamic reactive current output by the inverter and the voltage change. The value range of K3 is 1.5 - 2.5, and the value range of K4 is 0 - 1.5; U PCC is the per-unit value of the grid connection point voltage of the photovoltaic power station; I N is the rated output current value of the AC side of the inverter.

[0118] The above embodiments list the reactive power dynamic characteristics of the inverter side of HVDC transmission, the wind farm, and the PV power station. When DC and new energy are connected across voltage levels, their reactive power-voltage characteristics are coupled.

[0119] Step 203: Calculate the reactive power increment of each selected power-receiving node based on the reactive power increment calculation formula, where the reactive power increment calculation formula is:

[0120]

[0121] ΔQ i represents the reactive power increment of the power-receiving node i, and respectively represent the reactive power-voltage sensitivities of node i, node j, and the converter bus node k of the DC converter station, ΔU i represents the change in voltage amplitude of the power-receiving node i, μ i,j represents the voltage influence degree of the power-receiving node i on the power-receiving node j, μ i,k represents the voltage influence degree of the power-receiving node i on the converter bus node k of the converter station.

[0122] Step 204: Calculate the voltage influence degree between power-receiving nodes based on the first voltage influence degree calculation formula, and calculate the voltage influence degree between the power-receiving node and the converter bus node of the converter station based on the second voltage influence degree calculation formula, where the first voltage influence degree calculation formula is:

[0123]

[0124] The second voltage influence degree calculation formula is:

[0125]

[0126] μ i,j represents the voltage influence degree of the power-receiving node i on the power-receiving node j, μ i,k represents the voltage influence degree of the power-receiving node i on the converter bus node k of the converter station, ΔQ i represents the reactive power increment of the power-receiving node i, ΔQ i,j and ΔQ i,k respectively represent the reactive power increment flowing from the power-receiving node i to the power-receiving node j and the power-receiving node k.

[0127] Next, calculate the reactive power increment of each selected power-receiving node based on the reactive power increment calculation formula.

[0128] Specifically, according to the power flow calculation equation, the relationship between the state variables P, Q, δ, and U in the power grid system is:

[0129]

[0130] ΔP is the active power increment of the node; ΔQ is the reactive power increment of the node; Δδ is the node voltage angle increment; ΔU is the node voltage amplitude increment. Among them,

[0131] Only consider the influence of changing the node reactive power on the voltage amplitude of other nodes, and ignore the influence generated by the node active power, that is, set the injection amount of active power to 0, and calculate the sub-matrix of the Jacobian matrix in the correction equation.

[0132] Thus, it can be obtained that:

[0133]

[0134] Matrix S Q is the reactive power-voltage sensitivity matrix.

[0135] Next, based on the first voltage influence degree calculation formula, calculate the voltage influence degree between the power receiving nodes, and based on the second voltage influence degree calculation formula, calculate the voltage influence degree between the power receiving node and the converter bus node of the converter station. Specifically, as Figure 6 shown, Figure 6 is the system schematic diagram under the coupling of HVDC and new energy across voltage levels, Figure 6 in which node i represents the concerned bus node, node k represents the converter bus node of the DC converter station, and node j represents the grid connection point of new energy. Therefore:

[0136]

[0137] ΔQ i is the reactive power change amount of node i; are the reactive power-voltage sensitivities of node i, node j, and node k respectively; ΔU i , ΔU j , ΔU k are the voltage change amounts of node i, node j, and node k respectively.

[0138] If reactive power compensation is implemented at the regulating station on the concerned node i, the initial voltage of this node is U i , when the regulating station adds reactive power of ΔQ i , let the reactive power flowing from node i to node j be ΔQ i,j , the reactive power flowing to node k be ΔQ i,k , the reactive power increment of node i itself be ΔQ i,i , the reactive power-voltage sensitivities of node i, node j, and node k and can be expressed as:

[0139]

[0140] ΔU i , ΔU j and ΔU k Represent the voltage changes at node i, node j and node k respectively. The influence μ is used to measure the reactive power support of node i to node j and node k. i,i Indicates the influence of node i on its own node voltage, μ i,j and μ i,k They represent the ability of node i to adjust the voltage of node j and node k respectively:

[0141]

[0142] If we know μ i,j , μ i,k and the reactive power increment ΔQ of node i i , then the reactive power increment ΔQ flowing to node j and node k i,j and ΔQ i,k They can be expressed as:

[0143]

[0144] Finally, the reactive power increment ΔQ of the concerned node i under cross-voltage level coupling can be obtained: i The relationship with the node voltage increment is:

[0145]

[0146] and represents the reactive power-voltage sensitivity of nodes i, j and k; μ i,j and μ i,k Indicates the influence of node i on node j and node k; and Respectively represent the reactive power-voltage coefficient of node i, node j and node k, where:

[0147]

[0148] Step 205, based on the voltage amplitude change calculation formula and the reactive power increment of each selected power receiving node, the voltage amplitude change of the selected power receiving node is calculated, wherein the voltage amplitude change calculation formula is:

[0149]

[0150] μ i,j represents the voltage influence of power receiving node i on power receiving node j, and Respectively represent the reactive voltage coefficient of the receiving nodes i and j, ΔQi and ΔQ j respectively represent the reactive power increments of the power receiving nodes i and j.

[0151] Next, based on the voltage amplitude change calculation formula and the reactive power increments of the selected power receiving nodes, calculate the voltage amplitude change of the selected power receiving nodes.

[0152] Specifically, the degree of connection tightness between nodes is described based on the voltage - reactive power relationship as:

[0153]

[0154] α ij represents the voltage amplitude change of node i when the voltage amplitude change of node j is ΔU j ; α ji represents the voltage amplitude change of node j when the voltage amplitude change of node i is ΔU i

[0155] Step 206, based on the calculation formula for the coupling degree value between power receiving nodes and the voltage amplitude change of the selected power receiving nodes, calculate the coupling degree value between power receiving nodes, where the calculation formula for the coupling degree value between power receiving nodes is:

[0156]

[0157] D ij represents the coupling degree value between power receiving node i and power receiving node j, and α ij represents the voltage amplitude change of power receiving node i when the voltage amplitude change of power receiving node j is ΔU j ; α ji represents the voltage amplitude change of power receiving node j when the voltage amplitude change of power receiving node i is ΔU i

[0158] Next, based on the calculation formula for the coupling degree value between power receiving nodes and the voltage amplitude change of the selected power receiving nodes, calculate the coupling degree value between power receiving nodes. Specifically, use logarithmic transformation to map the mathematical distance to the vector space, and define the coupling relationship D between DC and new energy based on voltage - reactive power sensitivity ij :

[0159] D ij = D ji = lg(α ij ×α ji + 1)×10 2 ,

[0160] α ij ×α ji is to ensure the symmetry of D ij α​​ij ×α ji +1 ensures the positive definiteness of D ij . α ij ×α ji The larger the α coefficient, the stronger the coupling between the two nodes; the lower the α ij ×α ji , the weaker the coupling between the two nodes.

[0161] Step 207: When the coupling degree value between the power receiving nodes is greater than or equal to the preset coupling degree threshold, the characterization result of the coupling characteristics between the selected power receiving nodes is that there is a coupling relationship, where the coupling degree value between the power receiving nodes characterizes the critical coupling degree between the DC energy and the new energy across voltage levels obtained with triggering the new energy high-voltage or low-voltage crossing as the critical condition.

[0162] Step 208: When the coupling degree value between the power receiving nodes is less than the preset coupling degree threshold, the characterization result of the coupling characteristics between the selected power receiving nodes is that there is no coupling relationship.

[0163] Finally, when the coupling degree value between the power receiving nodes is greater than or equal to the preset coupling degree threshold, the characterization result of the coupling characteristics between the selected power receiving nodes is that there is a coupling relationship; when the coupling degree value between the power receiving nodes is less than the preset coupling degree threshold, the characterization result of the coupling characteristics between the selected power receiving nodes is that there is no coupling relationship.

[0164] In particular, the coupling degree value between the power receiving nodes characterizes the critical coupling degree between the DC energy and the new energy across voltage levels obtained with triggering the new energy high-voltage or low-voltage crossing as the critical condition.

[0165] In a specific embodiment, for example Figure 2 as shown, in the modified New England 10-machine 39-bus system, DC is fed into the power receiving node 8 as the DC node i, and new energy is grid-connected at nodes 5, 6, 32, and 34 as the new energy nodes j, and the sensitivity and coupling relationship between the DC node i and the new energy node j are calculated, and the results are shown in Table 1.

[0166] Table 1

[0167]

[0168] When a three-phase short-circuit fault occurs in the transmission line between the DC near-area power receiving nodes 7 and 8, the relationship between the DC node i and the new energy node j and the voltage drop of the new energy node are as Figure 7 shown. When a bipolar blocking fault occurs in the DC, the relationship between the DC node i and the new energy node j and the voltage rise of the new energy node are as Figure 8 shown. From Figure 7 and Figure 8It can be seen that the voltage drop / lift condition at the new energy grid connection point is closely related to the coupling relationship between the DC node i and the new energy node j.

[0169] The new energy grid connection point can use 0.9 and 1.1 of the voltage amplitude as thresholds to obtain the critical coupling degrees D0.9 and D1.1 under different voltage levels for DC and new energy. When the coupling degree D between the DC node and the new energy node is greater than D0.9, it indicates that there is a coupling relationship between them, and the greater the value of D, the stronger the coupling; vice versa; similarly, when the coupling degree D between the DC node and the new energy node is greater than D1.1, the above conclusion also holds.

[0170] By applying the technical solution of this embodiment, first, the reactive power-voltage characteristics of the inverter side of the DC transmission system and the new energy grid connection system are respectively deduced. On this basis, the dynamic reactive power-voltage characteristics of the system under different voltage levels for DC and new energy are analyzed. Then, based on the concept of voltage-reactive power sensitivity, a characterization method for the coupling characteristics of DC and new energy under different voltage levels is proposed. Finally, taking whether to trigger the high / low voltage ride-through of new energy as the critical condition, the critical coupling degree under different voltage levels for DC and new energy is obtained. Simulation analysis is carried out on the modified New England 10-machine 39-bus system to verify the coupling degree between DC and new energy when a three-phase short circuit occurs in the near area of the DC system, resulting in DC bipolar blocking.

[0171] Further, as Figure 1 a specific implementation of the method, the embodiment of the present application provides a device for characterizing the grid coupling characteristics, which is applied to the receiving-end grid. As Figure 9 shown, the device includes:

[0172] A power receiving node acquisition module 301, configured to acquire a plurality of power receiving nodes in the receiving-end grid, where the energy of the power receiving nodes is DC energy or new energy, and the new energy includes wind power generation energy and photovoltaic power generation energy;

[0173] A coupling characteristic acquisition module 302, configured to select a power receiving node with DC energy as the energy and a power receiving node with new energy as the energy, and acquire the reactive power-voltage coupling characteristics between the selected power receiving nodes according to the reactive power-voltage dynamic characteristics of DC energy and the reactive power-voltage dynamic characteristics of new energy;

[0174] A coupling characteristic characterization module 303, configured to calculate the coupling degree value between the power receiving nodes based on the reactive power-voltage coupling characteristics between the selected power receiving nodes, and determine the characterization result of the coupling characteristics between the selected power receiving nodes based on the comparison between the coupling degree value between the power receiving nodes and a preset coupling degree threshold.

[0175] Optionally, the coupling characteristic characterization module 303 is further configured to:

[0176] Obtain the voltage amplitude change of the selected power receiving node;

[0177] Based on the calculation formula for the coupling degree value between power receiving nodes and the voltage amplitude change of each selected power receiving node, calculate the coupling degree value between power receiving nodes. Among them, the calculation formula for the coupling degree value between power receiving nodes is:

[0178]

[0179] D ij represents the coupling degree value between power receiving node i and power receiving node j, α ij represents the voltage amplitude change of power receiving node i when the voltage amplitude change of power receiving node j is ΔU j , α ji represents the voltage amplitude change of power receiving node i when the voltage amplitude change of power receiving node i is ΔU i , the voltage amplitude change of power receiving node j.

[0180] Optionally, the coupling characteristic acquisition module 302 is further configured to:

[0181] Obtain the reactive power increment of each selected power receiving node;

[0182] Based on the voltage amplitude change calculation formula and the reactive power increment of each selected power receiving node, calculate the voltage amplitude change of the selected power receiving node. Among them, the voltage amplitude change calculation formula is:

[0183]

[0184] α ij represents the voltage amplitude change of power receiving node i when the voltage amplitude change of power receiving node j is ΔU j , α ji represents the voltage amplitude change of power receiving node i when the voltage amplitude change of power receiving node i is ΔU i , the voltage amplitude change of power receiving node j, μ i,j represents the voltage influence degree of power receiving node i on power receiving node j, and respectively represent the reactive power-voltage coefficients of power receiving nodes i and j, ΔQ i and ΔQ j respectively represent the reactive power increments of power receiving nodes i and j.

[0185] Optionally, the coupling characteristic acquisition module 302 is further configured to:

[0186] Based on the reactive power increment calculation formula, calculate the reactive power increment of each selected power receiving node. Among them, the reactive power increment calculation formula is:

[0187]

[0188] ΔQ i represents the reactive power increment of the power receiving node i and respectively represent the reactive power-voltage sensitivities of node i, node j, and the commutation bus node k of the DC converter station. ΔU i represents the change in the voltage amplitude of the power receiving node i, and μ i,j represents the voltage influence degree of the power receiving node i on the power receiving node j, and μ i,k represents the voltage influence degree of the power receiving node i on the commutation bus node k of the converter station.

[0189] Optionally, the coupling characteristic acquisition module 302 is further configured to:

[0190] Calculate the voltage influence degree between power receiving nodes based on the first voltage influence degree calculation formula, and calculate the voltage influence degree between the power receiving node and the commutation bus node of the converter station based on the second voltage influence degree calculation formula, where the first voltage influence degree calculation formula is:

[0191]

[0192] The second voltage influence degree calculation formula is:

[0193]

[0194] μ i,j represents the voltage influence degree of the power receiving node i on the power receiving node j, and μ i,k represents the voltage influence degree of the power receiving node i on the commutation bus node k of the converter station, ΔQ i represents the reactive power increment of the power receiving node i, ΔQ i,j and ΔQ i,k respectively represent the reactive power increment flowing from the power receiving node i to the power receiving node j and the power receiving node k.

[0195] Optionally, the coupling degree value between the power receiving nodes characterizes the critical coupling degree between the DC energy and the new energy under different voltage levels with triggering the high-voltage or low-voltage crossing of the new energy as the critical condition.

[0196] Optionally, the coupling characteristic characterization module 303 is further configured to:

[0197] When the coupling degree value between the power receiving nodes is greater than or equal to the preset coupling degree threshold, the coupling characteristic characterization result between the selected power receiving nodes is that there is a coupling relationship;

[0198] When the coupling degree value between the power receiving nodes is less than the preset coupling degree threshold, the coupling characteristic characterization result between the selected power receiving nodes is that there is no coupling relationship.

[0199] It should be noted that for other corresponding descriptions of each functional unit involved in the power grid coupling characteristic characterization device provided in the embodiments of the present application, reference can be made to Figure 1 and Figure 3 the corresponding descriptions in the method, which will not be elaborated here.

[0200] Based on the above as Figure 1 and Figure 3 shown in the method, correspondingly, the embodiments of the present application also provide a storage medium, on which a computer program is stored, and when the computer program is executed by a processor, it implements the power grid coupling characteristic characterization method as shown in Figure 1 and Figure 3 above.

[0201] Based on such an understanding, the technical solution of the present application can be embodied in the form of a software product, and the software product can be stored in a non-volatile storage medium (which can be a CD-ROM, a USB flash drive, a mobile hard disk, etc.), including several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in various implementation scenarios of the present application.

[0202] Based on the above as Figure 1 and Figure 3 shown in the method, and Figure 9 shown in the virtual device embodiment, in order to achieve the above object, the embodiments of the present application also provide a computer device, which can specifically be a personal computer, a server, a network device, etc. The computer device includes a storage medium and a processor; the storage medium is used to store a computer program; the processor is used to execute the computer program to implement the power grid coupling characteristic characterization method as shown in Figure 1 and Figure 3 above.

[0203] Optionally, the computer device may further include a user interface, a network interface, a camera, a radio frequency (RF) circuit, sensors, an audio circuit, a WI-FI module, etc. The user interface may include a display screen (Display), an input unit such as a keyboard (Keyboard), etc. Optionally, the user interface may further include a USB interface, a card reader interface, etc. The network interface may optionally include a standard wired interface, a wireless interface (such as a Bluetooth interface, a WI-FI interface), etc.

[0204] Those skilled in the art can understand that the structure of a computer device provided in this embodiment does not constitute a limitation to the computer device, and it may include more or fewer components, or combine certain components, or have different component arrangements.

[0205] The storage medium may also include an operating system and a network communication module. The operating system is a program for managing and storing the hardware and software resources of a computer device, and supports the operation of information processing programs and other software and / or programs. The network communication module is used to implement communication between components inside the storage medium, as well as communication with other hardware and software in the entity device.

[0206] Through the description of the above embodiments, those skilled in the art can clearly understand that the present application can be implemented by means of software plus a necessary general hardware platform, or can be implemented by hardware to obtain multiple power receiving nodes in the receiving-end power grid, where the energy of the power receiving node is DC energy or new energy, and the new energy includes wind power generation energy and photovoltaic power generation energy; select any power receiving node with DC energy as the energy and any power receiving node with new energy as the energy, and obtain the reactive voltage coupling characteristics between the selected power receiving nodes according to the reactive voltage dynamic characteristics of DC energy and the reactive voltage dynamic characteristics of new energy; based on the reactive voltage coupling characteristics between the selected power receiving nodes, calculate the coupling degree value between the power receiving nodes, and based on the comparison between the coupling degree value between the power receiving nodes and a preset coupling degree threshold, determine the coupling characteristic representation result between the selected power receiving nodes, so as to realize the representation of the coupling degree of DC and new energy across voltage levels.

[0207] Those skilled in the art can understand that the drawings are only schematic diagrams of a preferred implementation scenario, and the modules or processes in the drawings are not necessarily essential for implementing the present application. Those skilled in the art can understand that the modules in the device in the implementation scenario can be distributed in the device in the implementation scenario according to the description of the implementation scenario, or can be correspondingly changed and located in one or more devices different from this implementation scenario. The modules in the above implementation scenario can be combined into one module, or further split into multiple sub-modules.

[0208] The above serial numbers of the present application are only for description and do not represent the advantages or disadvantages of the implementation scenarios. The above disclosure is only several specific implementation scenarios of the present application. However, the present application is not limited thereto, and any changes that can be thought of by those skilled in the art should fall within the protection scope of the present application.

Claims

1. A method for characterizing the grid coupling characteristics, characterized in that, Applied to the receiving-end power grid; the method includes: Obtain multiple power receiving nodes in the receiving-end power grid, where the energy of the power receiving nodes is DC energy or new energy, and the new energy includes wind power generation energy and photovoltaic power generation energy; Select any power receiving node with DC energy as its energy and any power receiving node with new energy as its energy, and obtain the reactive voltage coupling characteristics between the selected power receiving nodes according to the reactive voltage dynamic characteristics of DC energy and the reactive voltage dynamic characteristics of new energy; Obtain the voltage amplitude change of the selected power receiving nodes; Based on the calculation formula for the coupling degree value between power receiving nodes and the voltage amplitude change of each selected power receiving node, calculate the coupling degree value between power receiving nodes, where the coupling degree value between power receiving nodes is obtained by mapping the mathematical distance to the vector space using logarithmic transformation, and the coupling degree value between power receiving nodes is used to characterize the coupling relationship between DC and new energy based on voltage-reactive power sensitivity. The calculation formula for the coupling degree value between power receiving nodes is: D ij = D ji = lg(α ij × α ji + 1) × 10 2 , D ij is the same as D, and equally represents the coupling degree value between the power receiving node i and the power receiving node j. α ji represents the voltage amplitude change of the power receiving node i when the voltage amplitude change of the power receiving node j is ΔU ij ; α j represents the voltage amplitude change of the power receiving node j when the voltage amplitude change of the power receiving node i is ΔU ji ; α i ×α ij is used to ensure the symmetry of D ji ; α ij ×α ij +1 is used to ensure the positive definiteness of D ji ; α ij ×α ij The larger the coefficient, the stronger the coupling between the two nodes. α ji ×α ij The lower it is, the weaker the coupling between the two nodes. ji And and respectively represent the reactive power voltage coefficients of the power receiving nodes i and j. μ i,j represents the voltage influence degree of the power receiving node i on the power receiving node j. μ j,i represents the voltage influence degree of the power receiving node j on the power receiving node i. Q i And Q j respectively represent the reactive powers of the power receiving nodes i and j. U i And U j respectively represent the voltages of the power receiving nodes i and j; Based on the comparison between the coupling degree value between power receiving nodes and the preset coupling degree threshold, determine the characterization result of the coupling characteristics between the selected power receiving nodes.

2. The method according to claim 1, characterized in that, The obtaining of the voltage amplitude change of the selected power receiving nodes includes: Obtain the reactive power increment of each selected power receiving node; Based on the voltage amplitude change calculation formula and the reactive power increment of each selected power receiving node, calculate the voltage amplitude change of the selected power receiving nodes, where the voltage amplitude change calculation formula is: α ij represents the voltage amplitude change of the power receiving node j as ΔU j when the voltage amplitude change of the power receiving node i is α ji represents the voltage amplitude change of the power receiving node i as ΔU i when the voltage amplitude change of the power receiving node j is μ i,j represents the voltage influence degree of the power receiving node i on the power receiving node j, μ j,i represents the voltage influence degree of the power receiving node j on the power receiving node i and respectively represent the reactive power - voltage coefficients of the power receiving nodes i and j, ΔQ i and ΔQ j respectively represent the reactive power increments of the power receiving nodes i and j 3. The method according to claim 2, wherein The obtaining of the reactive power increment of each selected power receiving node includes: Based on the reactive power increment calculation formula, calculate the reactive power increment of each selected power receiving node, where the reactive power increment calculation formula is: ΔQ i represents the reactive power increment of the power receiving node i, and respectively represent the reactive power-voltage sensitivities of node i, node j, and the commutation bus node k of the DC converter station. ΔU i represents the change in the voltage amplitude of the power receiving node i, and μ i,j represents the voltage influence degree of the power receiving node i on the power receiving node j, and μ i,k represents the voltage influence degree of the power receiving node i on the commutation bus node k of the converter station.

4. The method according to claim 3, characterized in that, Before calculating the reactive power increment of each selected power receiving node based on the reactive power increment calculation formula, the method further includes: Based on the first voltage influence degree calculation formula, calculate the voltage influence degree between power receiving nodes, and based on the second voltage influence degree calculation formula, calculate the voltage influence degree between the power receiving node and the converter bus node of the converter station, where the first voltage influence degree calculation formula is: The second voltage influence degree calculation formula is: μ i,j represents the voltage influence degree of the power receiving node i on the power receiving node j, μ i,k represents the voltage influence degree of the power receiving node i on the commutation bus node k of the converter station, ΔQ i represents the reactive power increment of the power receiving node i, ΔQ i,j and ΔQ i,k respectively represent the reactive power increments flowing from the power receiving node i to the power receiving node j and the power receiving node k.

5. The method according to claim 1, wherein The coupling degree value between power receiving nodes characterizes the critical coupling degree between DC energy and new energy across voltage levels with triggering high-voltage or low-voltage crossing of new energy as the critical condition.

6. The method according to any one of claims 1 to 5, characterized in that The determining of the characterization result of the coupling characteristics between the selected power receiving nodes based on the comparison between the coupling degree value between power receiving nodes and the preset coupling degree threshold includes: When the coupling degree value between power receiving nodes is greater than or equal to the preset coupling degree threshold, the characterization result of the coupling characteristics between the selected power receiving nodes is that there is a coupling relationship; When the coupling degree value between power receiving nodes is less than the preset coupling degree threshold, the characterization result of the coupling characteristics between the selected power receiving nodes is that there is no coupling relationship.

7. A device for characterizing the grid coupling characteristics, characterized in that, Applied to the receiving-end power grid; the device includes: A power receiving node acquisition module, configured to acquire multiple power receiving nodes in the receiving-end power grid, where the energy of the power receiving nodes is DC energy or new energy, and the new energy includes wind power generation energy and photovoltaic power generation energy; A coupling characteristic acquisition module, configured to select a power receiving node with any energy being DC energy and a power receiving node with any energy being new energy, and acquire the reactive voltage coupling characteristic between the selected power receiving nodes according to the reactive voltage dynamic characteristic of the DC energy and the reactive voltage dynamic characteristic of the new energy; A coupling characteristic characterization module, configured to obtain the voltage amplitude change of the selected power receiving nodes, and calculate the coupling degree value between the power receiving nodes based on the coupling degree value calculation formula between the power receiving nodes and the voltage amplitude change of each selected power receiving node. Among them, the coupling degree value between the power receiving nodes is obtained by mapping the mathematical distance to the vector space through logarithmic transformation. The coupling degree value between the power receiving nodes is used to characterize the coupling relationship between the DC and the new energy based on the voltage reactive sensitivity. The coupling degree value calculation formula between the power receiving nodes is: D ij = D ji = lg(α ij × α ji + 1) × 10 2 , D ij is the same as D ji which represents the coupling degree value between the power receiving nodes i and j. α ij represents the voltage amplitude change of the power receiving node j as ΔU j at which time, the voltage amplitude change of the power receiving node i, α ji represents the voltage amplitude change of the power receiving node i as ΔU i at which time, the voltage amplitude change of the power receiving node j, α ij ×α ji is used to ensure the symmetry of D ij , α ij ×α ji +1 is used to ensure the positive definiteness of D ij , α ij ×α ji The larger the coefficient, the stronger the coupling between the two nodes, α ij ×α ji The lower it is, the weaker the coupling between the two nodes and respectively represent the reactive power voltage coefficients of the power receiving nodes i and j, μ i,j represents the voltage influence degree of the power receiving node i on the power receiving node j, μ j,i represents the voltage influence degree of the power receiving node j on the power receiving node i, Q i and Q j respectively represent the reactive power of the power receiving nodes i and j, U i and U j respectively represent the voltages of the power receiving nodes i and j; The coupling characteristic characterization module is further configured to determine the coupling characteristic characterization result between the selected power receiving nodes based on the comparison between the coupling degree value between the power receiving nodes and a preset coupling degree threshold.

8. A storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the method for characterizing the grid coupling characteristics described in any one of claims 1 to 6.

9. A computer device, comprising a storage medium, a processor, and a computer program stored on the storage medium and executable on the processor, characterized in that, When the processor executes the computer program, it implements the method for characterizing the grid coupling characteristics described in any one of claims 1 to 6.

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