Calculation method of network following type wind power voltage stability boundary in network following / constructing wind power combined sending-out system and voltage stability improving method

Abstract

The invention discloses a method for calculating a grid following type wind power voltage stability boundary in a grid following / constructing wind power combined sending-out system and a voltage stability improving method, and belongs to the field of new energy power generation. And judging whether the voltage stability problem exists in the following grid type wind power under different outputs of the following grid type wind power and the combination of the potential reference values in the nodes of the following grid type wind power, so as to solve the combination boundary of different outputs of the following grid type wind power under the voltage stability constraint. According to the improvement method, under the condition that the voltage stability risk exists in the following wind power, the voltage stability of the system is improved by improving the internal potential reference value in the voltage droop control of the construction wind power, so that the voltage stability margin of the system is improved, the safe and stable operation of the system is guaranteed by a relatively economical means, and the system reliability is improved. And a feasible technical path is provided for safe, stable and economical operation of a novel power system.

Description

Technical Field

[0001] This invention belongs to the field of new energy power generation, and more specifically, relates to a method for calculating the voltage stability boundary of grid-connected wind power in a grid-connected wind power transmission system and a method for improving voltage stability. Background Technology

[0002] The joint transmission of multiple types of renewable energy through shared transmission channels has become a typical operational scenario. Currently, renewable energy units such as wind power and photovoltaic power employ either a grid-following control strategy that relies on phase-locked loops (PLLs) for synchronous grid connection and a grid-building control strategy that relies on virtual synchronous machines (VSMs) for synchronous grid connection and stability. The interrelationships between the control strategies of different types of renewable energy present new challenges to the stable operation of the system.

[0003] Regarding voltage stability, unlike traditional thermal power units, grid-connected wind and solar power units employ low-voltage ride-through (LVRT) control strategies. When the terminal voltage drops significantly, the control unit reduces active power output and increases reactive power output to prevent grid disconnection. However, LVRT control also introduces new voltage stability issues. Existing research indicates that when system faults cause fluctuations in the terminal voltage of grid-connected wind power units, these units may frequently enter and exit LVRT control states, leading to frequent voltage oscillations. Furthermore, if the terminal voltage level of grid-connected wind power units is low, they may be unable to exit LVRT control states after entering them, resulting in continuous voltage oscillations.

[0004] With the commissioning of wind turbines with different control types, wind farms are shifting from grid-connected control to a combination of grid-connected and grid-connected control. Because grid-connected wind power provides some support for system stability, combined grid-connected / grid-connected wind power transmission systems are gradually becoming a new type of sending-end system. Currently, analyses of voltage stability issues in grid-connected wind power are often conducted in single-unit grid-connected systems or systems bundled with either wind or thermal power, or solar or thermal power; research on combined grid-connected / grid-connected wind power transmission systems is relatively limited. Furthermore, the assessment methods for the voltage stability boundary of grid-connected wind power still rely heavily on electromagnetic transient simulation calculations, lacking quantitative analytical assessment methods.

[0005] Regarding strategies to improve voltage stability in grid-connected wind power, commonly used methods include configuring reactive power compensation devices such as SVG and SVC. This approach effectively addresses voltage stability issues in grid-connected wind power, but it increases equipment investment costs. Summary of the Invention

[0006] To address the aforementioned deficiencies or improvement needs of existing technologies, this invention provides a method for calculating the voltage stability boundary of grid-connected wind power in a grid-connected / grid-connected wind power combined transmission system and a method for improving voltage stability. This method can quantitatively analyze the combined output boundary of grid-connected / grid-connected wind power corresponding to the voltage stability of grid-connected wind power, and can be used to guide the establishment of a system safety and stability control strategy.

[0007] To achieve the above objectives, according to a first aspect of the present invention, a method for calculating the voltage stability boundary of grid-connected wind power in a grid-connected wind power combined transmission system is provided, comprising: S1, establish the grid-connected wind power terminal voltage based on the system's equivalent circuit. The mathematical expression of ; in, The mathematical expression is , To match the self-impedance of grid-connected wind turbine nodes, , , , Let S be the equivalent impedance between the infinite power source node S and the bus L. For grid-connected wind power terminal voltage Equivalent impedance between node and bus L The voltage at the infinite power supply node is... , These refer to the active power output and reactive power output of grid-connected wind power, respectively. The phase angle of the terminal voltage of a grid-connected wind turbine; S2, Calculate the transient process after a system failure when the system is running under the target scheduling instruction. minimum value and after system failure recovery steady-state value ,like or If the value is less than the low voltage ride-through command value, then the target scheduling command and the corresponding grid-connected wind power voltage stability problem type are saved to the strategy set, and proceed to S3; if , If all values ​​are not less than the low voltage ride-through command value, then proceed directly to S3; The target scheduling instruction includes , and reference values ​​for active power output and internal potential of grid-connected wind power nodes. ; To isolate the phase angle of the grid-connected wind turbine terminal voltage after system fault isolation maximum value Substitution The mathematical expression is obtained; To be Substitution The mathematical expression is obtained as follows: For the active power of grid-connected wind power equal Reference value hour The value; when When the voltage is less than the low-voltage ride-through command value, the type of voltage stability problem in grid-connected wind power is frequent low-voltage ride-through; when When the voltage is less than the low voltage ride-through command value, the type of voltage stability problem for grid-connected wind power is continuous low voltage ride-through. S3, Modify the target scheduling instruction , or At least one of the following is used to update the target scheduling instruction, return to S2, until the iteration stop condition is met, and use the current strategy set as the grid-type wind power voltage stability boundary strategy set.

[0008] According to a second aspect of the present invention, a method for improving the voltage stability of grid-connected wind power in a grid-connected wind power combined transmission system is provided, comprising: A1 will be part of the system's real-time scheduling instructions. As an index, the corresponding strategy is found from the set of grid-connected wind power voltage stability boundary strategies calculated using the calculation method described in any one of claims 1-4. and These serve as the active power output boundary and reactive power output boundary of grid-connected wind power, respectively. If the real-time dispatch command contains... or If the corresponding boundary is exceeded, the system has a grid-connected wind power voltage stability problem, and proceeds to A2; otherwise, the process ends. The system in question is a wind power transmission system integrated with the grid. A2, improve the real-time scheduling instructions of the system. ; A3, will be improved As an index, the corresponding strategy is found again from the set of grid-connected wind power voltage stability boundary strategies. and To update the active power output boundary and reactive power output boundary of grid-connected wind power respectively; A4, determine the real-time scheduling instruction in or Does it exceed the corresponding updated boundary? If so, raise it again. Return to A3 if necessary, otherwise end the process.

[0009] According to a third aspect of the present invention, an electronic device is provided, comprising: a computer-readable storage medium and a processor; The computer-readable storage medium is used to store executable instructions; The processor is configured to read executable instructions stored in the computer-readable storage medium and execute the method as described in the first or second aspect.

[0010] According to a fourth aspect of the invention, a computer-readable storage medium is provided, the computer-readable storage medium storing computer instructions for causing a processor to perform the method as described in the first or second aspect.

[0011] According to a fifth aspect of the invention, a computer program product is provided, comprising a computer program or instructions that, when executed by a processor, implement the method as described in the first or second aspect.

[0012] In summary, compared with the prior art, the above-described technical solutions conceived by this invention can achieve the following beneficial effects: The present invention provides a method for calculating the voltage stability boundary of grid-connected wind power in a combined grid-connected / grid-connected wind power transmission system. By analyzing the voltage expression of the grid-connected wind power terminals through the system's equivalent circuit, it determines whether there is a voltage stability problem for the grid-connected wind power under different power outputs and internal potential reference values ​​of the grid-connected wind power nodes. The method saves the different power outputs and internal potential reference values ​​of the grid-connected wind power nodes with voltage stability problems to form a set of voltage stability boundary strategies for grid-connected wind power, thereby solving for the boundary of different power output combinations of grid-connected / grid-connected wind power under voltage stability constraints.

[0013] The present invention provides a method for improving the voltage stability of grid-connected wind power in a combined grid-connected / grid-connected wind power transmission system. This method can predict and evaluate the voltage stability characteristics of grid-connected wind power based on the system operation mode and the actual output of the grid-connected / grid-connected wind power. When there is a risk of voltage stability in grid-connected wind power, the method can improve the system voltage stability by increasing the internal potential reference value in the voltage droop control of grid-connected wind power, thereby increasing the system voltage stability margin. This provides a feasible technical path for the safe, stable and economical operation of the system in a relatively economical way. Attached Figure Description

[0014] Figure 1 A flowchart illustrating the calculation method for the voltage stability boundary of grid-connected wind power in a grid-connected wind power combined transmission system provided in this embodiment of the invention; Figure 2(a) and Figure 2(b) are the structural diagram and equivalent circuit diagram of the wind power transmission system combined with the grid, respectively. Figures 3(a) and 3(b) are schematic diagrams of terminal voltage during frequent and continuous low-voltage ride-throughs of grid-connected wind power, respectively. Figure 4 A schematic diagram showing the results of obtaining the voltage stability boundary of grid-connected wind power under given system and control parameters; Figure 5 A flowchart of a method for improving the voltage stability of grid-connected wind power in a grid-connected wind power combined transmission system provided in an embodiment of the present invention; Figures 6(a) to 6(c) They are respectively =180MW A schematic diagram of the electromagnetic transient simulation results of GFL terminal voltage, GFL active / reactive power output, and GFL low-voltage signal when =1.13pu; Figures 7(a) to 7(c) They are respectively =540MW A schematic diagram of the electromagnetic transient simulation results of GFL terminal voltage, GFL active / reactive power output, and GFL low-voltage signal when =1.13pu; Figures 8(a) to 8(c) They are respectively =180MW A schematic diagram of the electromagnetic transient simulation results of GFL terminal voltage, GFL active / reactive power output, and GFL low-voltage signal when =1.22pu; Figures 9(a) to 9(c) They are respectively =540MW A schematic diagram of the electromagnetic transient simulation results of GFL terminal voltage, GFL active / reactive power output, and GFL low-voltage signal when =1.22pu; Figure 10 This is a block diagram for controlling voltage droop in grid-connected wind power systems. Detailed Implementation

[0015] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0016] In grid-connected wind power transmission systems, fault disturbances cause voltage fluctuations at the grid-connected end, leading to voltage instability issues such as frequent and sustained low-voltage ride-throughs, thus threatening the safe and stable operation of the power system. To prevent the risk of voltage instability in grid-connected wind power and improve system voltage levels, this invention proposes a method for calculating the voltage stability boundary of grid-connected wind power in grid-connected wind power transmission systems and a method for improving the voltage stability of grid-connected wind power in such systems. This method can evaluate the voltage stability characteristics of grid-connected wind power under different output combinations and improve system voltage stability by modifying the control strategy of the grid-connected wind power.

[0017] Specifically, this invention provides a method for calculating the voltage stability boundary of grid-connected wind power in a combined grid-connected wind power transmission system, comprising: S1, establish the grid-connected wind power terminal voltage based on the system's equivalent circuit. The mathematical expression for .

[0018] In step S1, the system parameters (including line parameters, transformer parameters, etc.) of the wind power transmission system with / with the grid are determined, as well as the control parameters of the wind power with the grid (including the reference value of the potential inside the wind power node, the virtual impedance of the wind power node and the voltage droop coefficient) and the output of the wind power with / with the grid (including the active power output of the wind power with and without the grid). The mathematical expression of the voltage at the end of the wind power with the grid is determined based on the equivalent circuit of the system.

[0019] The grid-connected wind power transmission system and its equivalent circuit are shown in Figure 2(a) and (b), respectively. The phasor of the grid-connected wind power terminal voltage is shown in Figure 2(a) and (b). It is the result of the combined effect of the infinite power source, the grid-connected wind power, and the current injected into the nodes of the grid-connected wind power, according to the principle of linear network superposition. As shown in the following formula:

[0020] right Decomposing dq yields:

[0021] Solving the above equation yields the voltage amplitude at the substation terminals of the grid type. The mathematical expression is as follows:

[0022] in, , , Let S be the equivalent impedance between the infinite power source node S and the bus L. For grid-connected wind power terminal voltage Equivalent impedance between node and bus L To match the self-impedance of grid-connected wind turbine nodes, The voltage at the infinite power supply node is... To inject current into grid-connected wind power, To contribute to grid-connected wind power, To match the reactive power output of grid-connected wind power, For the phase angle of the terminal voltage of grid-connected wind power, This refers to the phase angle of the voltage at the wind turbine terminals in the grid-connected system.

[0023] The value is affected by the network terminal voltage. The impact, The solution can be obtained through voltage droop control, and the formula is as follows:

[0024] in The internal potential of a grid-type wind power node. For the virtual impedance of grid-type wind power nodes, The d-axis component of the output current of grid-connected wind power is the active power output of grid-connected wind power. and terminal voltage The ratio determines, The q-axis component of the output current of grid-connected wind power is the active power output of grid-connected wind power. and terminal voltage The ratio determines, This is a reference value for the internal potential of a grid-connected wind power node. This is the voltage droop factor. For reference values ​​of reactive power in grid-connected wind power, To match the phase angle of the grid-connected wind turbine terminal voltage, For the phase angle of the terminal voltage of grid-connected wind power, To match the power factor of grid-connected wind power.

[0025] The solution can be obtained using the following formula:

[0026] S2, Calculate the transient process after a system failure when the system is running under the target scheduling instruction. minimum value and after system failure recovery steady-state value ,like or If the value is less than the low voltage ride-through instruction value, then the target scheduling instruction and the corresponding voltage stability problem type are saved to the strategy set, and proceed to S3; if , If all values ​​are not less than the low voltage ride-through command value, then proceed directly to S3; The target scheduling instruction includes , and reference values ​​for active power output and internal potential of grid-connected wind power nodes. ; To isolate the phase angle of the grid-connected wind turbine terminal voltage after system fault isolation maximum value Substitution The mathematical expression is obtained; To be Substitution The mathematical expression is obtained as follows: For the active power of grid-connected wind power Equivalent to the reference value of active power of grid-connected wind power hour The value; when When the voltage is less than the low-voltage ride-through command value, the type of voltage stability problem is frequent low-voltage ride-through; when When the voltage is less than the low voltage ride-through command value, the type of voltage stability problem is sustained low voltage ride-through.

[0027] In step S2, firstly, based on the mathematical expression for the grid-connected wind turbine terminal voltage, the minimum value of the grid-connected wind turbine terminal voltage during the transient process after a system fault is calculated when the system is running under the target dispatch command. and the steady-state value of the grid-connected wind turbine terminal voltage after fault recovery .

[0028] Based on the expression for the terminal voltage of a grid-connected wind turbine, the terminal voltage characteristic curves of the grid-connected wind turbine can be plotted, as shown in (a) and (b) of Figure 3.

[0029] The phase angle of the grid-type wind turbine terminal voltage after fault clearance can be calculated using the equal area rule. Maximum value ,Will Bring into The expression can be calculated to obtain Based on the network configuration, the output active power is... The expression, when Calculate the phase angle of the terminal voltage of the grid-type wind turbine. ,Will Bring into The expression can be calculated to obtain Among them, the reference value for active power of grid-connected wind power. Configure according to actual needs.

[0030] The expression is shown in the following formula, which applies to grid-connected wind power operating in unity power factor mode. .

[0031]

[0032] like If the value is less than the low voltage ride-through command value, during the fault recovery process, due to the phase angle of the grid-connected wind power... The swaying of wind turbines, along with grid-connected wind power, will cause them to repeatedly enter and exit the low-voltage ride-through state, resulting in frequent low-voltage ride-through phenomena. Under the final steady-state operation after fault recovery, they will exit the low-voltage ride-through state. If... If the voltage is less than the low voltage ride-through command value, the grid-connected wind power will continue to enter the low voltage ride-through state after the fault is recovered, resulting in a continuous low voltage ride-through phenomenon. Under the final steady-state operation after the fault is recovered, it will not exit the low voltage ride-through state.

[0033] Therefore, in step S2, if If the value is less than the low-voltage ride-through command value, then there is a voltage stability problem with the grid-connected wind power, and the type of voltage stability problem is frequent low-voltage ride-through. The target scheduling command of the system and the corresponding voltage stability problem type are saved to the strategy set, and the process proceeds to S3; if... If the value is less than the low voltage ride-through command value, then there is a voltage stability problem with the grid-connected wind power, and the type of voltage stability problem is continuous low voltage ride-through. The target scheduling command of the system and the corresponding voltage stability problem type are saved to the strategy set, and the process proceeds to S3; if... , If the values ​​are all not less than the low voltage ride-through command value, then there is no voltage stability problem with grid-connected wind power, and it can directly enter S3.

[0034] S3, Modify the target scheduling instruction , or At least one of the following is used to update the target scheduling instruction, return to S2, until the iteration stop condition is met, and use the current strategy set as the grid-type wind power voltage stability boundary strategy set.

[0035] In step S3, the target operating command of the system is modified (i.e., the reference value of the grid-connected wind power output, the grid-connected wind power output, or the grid-connected wind power voltage droop control voltage is modified). (at least one of the following), return to S2, until the iteration stopping condition is met, to obtain different voltage reference values ​​for grid-type wind power voltage droop control. Below is the set of boundary strategies for wind power output corresponding to grid-connected wind power voltage stability.

[0036] In other words, through the above steps, the active power output of the system under different network structures and different network configurations can be obtained. Below, we define the active power output combinations of grid-connected wind power corresponding to frequent low-voltage ride-through phenomena and the active power output combinations of grid-connected wind power corresponding to continuous low-voltage ride-through phenomena. These output combinations constitute the voltage stability boundary strategy set for grid-connected wind power.

[0037] The iteration stopping condition can be set to either the size of the strategy set reaching a preset size or the number of iterations reaching a preset number of iterations. To ensure that the grid-connected wind power voltage stability boundary strategy set covers as many operating instructions as possible that the system may receive, preferably, the iteration stopping condition is: traversing the system step by step according to a first preset step size. , The range of values, and the traversal according to the second preset step size. The range of values ​​for .

[0038] It is understandable that the first and second preset step sizes and , , The value range depends on all the execution instructions that the system may receive. , , The value of is determined.

[0039] The aforementioned grid-connected wind power output boundary strategy set is used to determine whether there is a grid-connected wind power voltage stability problem under real-time operation commands. The determination process includes: The system's real-time scheduling instructions As an index, the corresponding strategy is found from the set of grid-connected wind power voltage stability boundary strategies. and Each of these corresponds one-to-one as the active power output boundary and reactive power output boundary of the grid-connected wind power system. If the real-time dispatch command contains... or If the voltage exceeds the corresponding boundary, the system has a grid-connected wind power voltage stability problem; otherwise, the system does not have a grid-connected wind power voltage stability problem.

[0040] When the system experiences voltage stability issues with grid-connected wind power, the voltage reference value in the grid-connected wind power voltage droop control can be increased. To improve voltage stability, this invention provides a method for improving the voltage stability of grid-connected wind power in a grid-connected wind power combined transmission system, such as... Figure 4 As shown, it includes: A1 will be part of the system's real-time scheduling instructions. As an index, the corresponding strategy is found from the set of grid-connected wind power voltage stability boundary strategies calculated using the calculation method described in the above embodiments. and Each of these corresponds one-to-one as the active power output boundary and reactive power output boundary of the grid-connected wind power system. If the real-time dispatch command contains... or If the corresponding boundary is exceeded, the system has a grid-connected wind power voltage stability problem, and proceeds to A2; otherwise, the system does not have a grid-connected wind power voltage stability problem, and the process ends. The system in question is a wind power transmission system integrated with the grid. A2, improve the real-time scheduling instructions of the system. ; A3, will be improved As an index, the corresponding strategy is found again from the set of grid-connected wind power voltage stability boundary strategies. and To update the active power output boundary and reactive power output boundary of the grid-type wind power respectively one by one; A4, determine the real-time scheduling instruction in or Does it exceed the corresponding updated boundary? If so, raise it again. Return to A3 if necessary, otherwise end the process.

[0041] In steps A2 and A3, to ensure that the improved boundary strategy can be found in the grid-connected wind power voltage stability boundary strategy set... Preferably, in steps A2 and A3, the increase is made according to the second preset step size. .

[0042] The method provided by the present invention will be further illustrated below with a specific example.

[0043] The system parameters and grid-type wind power control parameters are shown in Table 1. A three-phase short-circuit fault is set at the point near the collecting bus L of line L1-II, lasting 0.1 seconds before line L1-II is disconnected. The boundary assessment results are as follows: Figure 4 As shown in Figure 3, when the system parameters and network control parameters change, the following results are obtained according to the method shown in Figure 3: Figure 4 The voltage stability boundary of grid-connected wind power is shown under the corresponding operating conditions. Boundary data are collected to form a strategy set.

[0044] If, during actual system operation, under the current operating mode, the combined active power output of grid-connected wind power exceeds the output combination corresponding to the voltage stability boundary of grid-connected wind power in the strategy set, then grid-connected wind power will experience voltage stability issues. This can be addressed based on... Figure 5 The grid-type voltage stabilization improvement method shown is to increase the voltage... This increases the voltage at the grid-connected wind turbine terminals, thereby improving the voltage stability characteristics of grid-connected wind turbines.

[0045] Using the system parameters and network-type equipment control parameters shown in Table 1, for example... Figure 4 The voltage stability boundary assessment results shown are verified. The output of the grid-type equipment is set. =2500MW, Figure 4 The active power output corresponding to frequent low voltage ride-throughs in grid-connected wind power is =180MW, the active power output corresponding to the sustained low voltage ride-through is =540MW. The PSCAD / EMTDC electromagnetic transient simulation results are shown in Figures 6(a)~(c) and 7(a)~(c), respectively. It can be seen that when When the capacity reaches 180MW, grid-connected wind power experiences frequent low-voltage ride-through phenomena. When the capacity reaches 540MW, grid-connected wind power experiences a sustained low-voltage ride-through phenomenon. Figure 4 The evaluation results shown correspond to each other.

[0046]

[0047] Will Increasing the voltage from 1.13 PU to 1.22 PU can effectively improve the voltage stability characteristics of grid-connected wind power. Figures 8(a)~(c) and 9(a)~(c) respectively demonstrate... Upgraded to 1.22 PU. =2500MW, Electromagnetic transient simulation results at 180MW and 540MW respectively. It can be seen that... When the capacity reaches 180MW and 540MW, grid-connected wind power will not experience frequent or continuous low voltage ride-through phenomena, and the voltage stability characteristics will be significantly improved.

[0048] This invention provides an electronic device, including: a computer-readable storage medium and a processor; The computer-readable storage medium is used to store executable instructions; The processor is used to read executable instructions stored in the computer-readable storage medium and execute the calculation method or enhancement method as described in any of the above embodiments.

[0049] This invention provides a computer-readable storage medium storing computer instructions that cause a processor to perform a calculation method or improvement method as described in any of the above embodiments.

[0050] This invention provides a computer program product, including a computer program or instructions, which, when executed by a processor, implement the calculation method or improvement method as described in any of the above embodiments.

[0051] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for calculating a voltage stability boundary of a grid-following wind power in a grid-following wind power and grid-forming network power joint transmission system, characterized in that, Comprising: S1, according to the equivalent circuit of the system to establish the voltage of the grid-connected wind power terminal mathematical expression; wherein, The mathematical expression of , is the self-impedance of the grid-connected wind power node, , , , is the equivalent impedance between the infinite power supply node S and the bus L, is the grid-connected wind power terminal voltage is the equivalent impedance between the node and the bus L, is the infinite power supply node voltage, , are the active power and the reactive power of the grid-connected wind power, is the phase angle of the grid-connected wind power terminal voltage. S2, Calculate the transient process after a system failure when the system is running under the target scheduling instruction. minimum value and after system failure recovery steady-state value ,like or If the value is less than the low voltage ride-through command value, then the target scheduling command and the corresponding grid-connected wind power voltage stability problem type are saved to the strategy set, and proceed to S3; if , If all values ​​are not less than the low voltage ride-through command value, then proceed directly to S3; The target scheduling instruction includes , and reference values ​​for active power output and internal potential of grid-connected wind power nodes. ; To isolate the phase angle of the grid-connected wind turbine terminal voltage after system fault isolation maximum value Substitution The mathematical expression is obtained; To be Substitution The mathematical expression is obtained as follows: For the active power of grid-connected wind power equal Reference value hour The value; when When the voltage is less than the low-voltage ride-through command value, the type of voltage stability problem in grid-connected wind power is frequent low-voltage ride-through; when When the voltage is less than the low voltage ride-through command value, the type of voltage stability problem for grid-connected wind power is continuous low voltage ride-through. S3, modify at least one of the target scheduling instruction in , or to update the target scheduling instruction, return to S2 until the iteration stopping condition is reached, and take the current strategy set as the grid-connected type wind power voltage stability boundary strategy set.

2. The method of claim 1, wherein, Networked wind power terminal voltage The calculation formula is: wherein, is the grid-forming wind power node internal voltage, is the grid-forming wind power node virtual impedance, , are the grid-forming wind power output current d-axis and q-axis components, respectively, , are the grid-forming wind power active and reactive power outputs, respectively, is the grid-forming wind power node internal voltage reference, is the voltage droop coefficient, is the grid-forming wind power reactive reference, is the grid-forming wind power terminal voltage phase angle, is the grid-following wind power terminal voltage phase angle, is the grid-following wind power terminal power factor.

3. The method of claim 1 or 2, wherein, Grid-connected wind power active power The calculation formula is: wherein, is the grid-forming wind power terminal voltage phase angle, is the grid-following wind power terminal voltage phase angle, is the grid-following wind power terminal power factor.

4. The method of claim 1, wherein, The iteration stopping condition is that the value range of the first preset step is traversed respectively according to the first preset step, and the value range of the second preset step is traversed according to the second preset step. , The value range of the second preset step is traversed according to the second preset step. The value range of the second preset step is traversed according to the second preset step.

5. A method for improving voltage stability of a grid-connected wind power in a grid-connected wind power and transmission system, characterized in that, Comprising: A1, if the real-time dispatch instruction of the system is As an index, find the corresponding and respectively as the active power output boundary and the reactive power output boundary of the grid-connected wind power, if the real-time dispatch instruction or exceeds the corresponding boundary, the system has a grid-connected wind power voltage stability problem, enter A2, otherwise end; The system is a follow / structure network wind power joint transmission system; A2, improving the real-time scheduling instructions of the system ; A3, the improved As an index, again find the corresponding and to update the active power output boundary and the reactive power output boundary of the grid-connected wind power respectively; A4, determine whether the real-time scheduling instruction exceeds the corresponding updated boundary, if yes, again increase the priority of the real-time scheduling instruction or return to A3, otherwise end. return to A3, otherwise end.

6. The method of claim 5, wherein, In steps A2 and A3, both are increased by a second preset step size .

7. An electronic device, comprising: Comprising: The computer readable storage medium and the processor; The computer readable storage medium is used for storing executable instructions; The processor is used for reading the executable instructions stored in the computer readable storage medium, and executing the calculation method of any one of claims 1-4 or the promotion method of claim 5 or 6.

8. A computer-readable storage medium, characterized in that, The computer readable storage medium stores computer instructions, and the computer instructions are used for making the processor execute the calculation method of any one of claims 1-4 or the promotion method of claim 5 or 6.

9. A computer program product comprising computer programs or instructions, characterized in that, The computer program or instructions are executed by the processor to realize the calculation method of any one of claims 1-4 or the promotion method of claim 5 or 6.

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