Method and device for improving voltage stability margin of power system, medium and equipment

Abstract

The invention discloses a voltage stability margin improving method and device of an electric power system, a medium and equipment, and relates to the technical field of operation and maintenance of the electric power system. Under the condition that the voltage stability margin of the power system is smaller than a stability threshold value, calculating the global sensitivity of each tie line in the power system; the global sensitivity represents the influence degree of the corresponding tie line on the voltage stability margin of the power system; according to the global sensitivity of each tie line, determining a target tie line participating in voltage stability margin improvement; solving the tie line active power modulation model according to the operation parameters of the target tie line to obtain the active power adjustment amount of the target tie line; and adjusting the power of the target tie line through the active power adjustment amount of the target tie line so as to improve the voltage stability margin of the power system. According to the method, the voltage stability margin of the electric power system can be improved under active directional modulation with relatively low cost on the basis of existing coordinable resources.

Description

Technical Field

[0001] The present invention relates to the field of power system operation and maintenance technology, and in particular to a method, device, medium and equipment for improving voltage stability margin of a power system. Background Art

[0002] At present, with the interconnection of modern large power grids and the large-scale development and utilization of new energy, the reactive voltage support capacity of the system has gradually declined, which has aggravated the complexity of voltage stability analysis. Since the voltage stability of the power system is closely related to reactive power, the improvement of transient voltage stability margin generally takes optimizing reactive power distribution and improving voltage stability margin as the primary goal. However, there is also a strong coupling relationship between system voltage stability and active power. For large-scale transmission networks, when the reactive power supply at the receiving end is limited, the transmission of active power of the tie line has a certain regulatory potential for improving the voltage stability margin.

[0003] However, there is a lack of research on the improvement of voltage stability margin by active power in existing technologies. On the other hand, the formulation of preventive control measures requires a certain economic cost, especially for new generation phase regulators and STATCOMs, which often need to solve the trade-off between safety and economy in the operation planning stage.

[0004] Therefore, there is an urgent need in the prior art for a method of improving the voltage stability margin of a power system under active power directional modulation at a lower cost. Summary of the invention

[0005] Based on this, it is necessary to provide a method, device, medium and equipment for improving the voltage stability margin of the power system to address the above-mentioned technical problems. The method can improve the voltage stability margin of the power system under active directional modulation at a lower cost based on existing coordinated resources.

[0006] The present invention adopts the following technical solutions: The present invention provides a method for improving voltage stability margin of an electric power system, comprising: When the voltage stability margin of the power system is less than the stability threshold, the global sensitivity of each tie line in the power system is calculated; the global sensitivity indicates the influence of the corresponding tie line on the voltage stability margin of the power system; According to the global sensitivity of each tie line, determine the target tie line that participates in improving the voltage stability margin; According to the operating parameters of the target tie line, the tie line active modulation model is solved to obtain the active power adjustment of the target tie line; the tie line active modulation model includes the objective function and tie line power balance constraints, tie line adjustable capacity limit constraints, voltage stability margin improvement constraints and voltage operation level and other voltage constraints; the objective function is constructed with the goal of minimizing the cost required to adjust the target tie line; The power of the target interconnection line is adjusted by adjusting the active power of the target interconnection line to improve the voltage stability margin of the power system.

[0007] Preferably, calculating the global sensitivity of each tie line in the power system includes: Obtain the active power and voltage stability margin of each tie line in the historical time period; The global sensitivity of each tie line is determined according to the active power and voltage stability margin of each tie line in the historical time period.

[0008] Preferably, the calculation formula of global sensitivity includes: ; in, is the global sensitivity matrix, and the element values ​​in the global sensitivity matrix represent the global sensitivity of each tie line. , is the number of tie lines; Represents the voltage stability margin, express The transpose of express The Gram matrix of , express The inverse of and Respectively i The contact line and j Active power of the interconnection lines; , yes , , express The transpose of Active power The probability distribution function of represents the bias term, for dimension and all elements are Column vector of ; Represents the product of corresponding matrix elements.

[0009] Preferably, according to the global sensitivity of each tie line, determining the target tie line participating in the improvement of the voltage stability margin includes: The tie line whose global sensitivity is greater than the sensitivity threshold is determined as the target tie line.

[0010] Preferably, before determining the target tie line participating in improving the voltage stability margin according to the global sensitivity of each tie line, the method further comprises: The tie lines whose absolute value of the difference between the active power in the power system and the preset power threshold is less than the preset difference are eliminated.

[0011] Preferably, the objective function is: ; in, is the objective function value, is the number of target contact lines, and Respectively j The active positive adjustment cost coefficient and the active negative adjustment cost coefficient of the target interconnection line; and Respectively j The active positive power adjustment and the active negative power adjustment of the target interconnection line; The tie line power balance constraint is: ; The constraints on the adjustable capacity of the tie line are: ; in, and Respectively j The upper limit and lower limit of active power of the target interconnection line; Before adjustment j Active power of the target interconnection line; The voltage stability margin improvement constraint is: ; in, is the global sensitivity; is the preset minimum voltage stability margin threshold value; is the current voltage stability margin of the power system; is the compensation factor; Voltage constraints such as voltage operating level are: ; in, and To ensure the safe operation of the power system. iThe upper and lower limits of the voltage amplitude of the target tie line; For the i The voltage value of the target interconnection line.

[0012] Preferably, the active power adjustment includes an active positive power adjustment or an active negative power adjustment; and according to the operating parameters of the target tie line, solving the tie line active modulation model to obtain the active power adjustment of the target tie line includes: The operating parameters of the target tie line are substituted into the objective function and various constraints. Under the condition of satisfying various constraints, the active positive power adjustment amount or the active negative power adjustment amount of the target tie line is determined with the objective of minimizing the objective function.

[0013] The present invention provides a device for improving voltage stability margin of an electric power system, comprising: A calculation module, used for calculating the global sensitivity of each tie line in the power system when the voltage stability margin of the power system is less than the stability threshold; the global sensitivity indicates the influence degree of the corresponding tie line on the voltage stability margin of the power system; A first determination module is used to determine a target tie line that participates in improving the voltage stability margin according to the global sensitivity of each tie line; The second determination module is used to solve the tie line active modulation model according to the operating parameters of the target tie line to obtain the active power adjustment amount of the target tie line; the tie line active modulation model includes an objective function and tie line power balance constraints, tie line adjustable capacity limit constraints, voltage stability margin improvement constraints, and voltage operation level and other voltage constraints; the objective function is constructed with the goal of minimizing the cost required to adjust the target tie line; The adjustment module is used to adjust the power of the target interconnection line through the active power adjustment amount of the target interconnection line to improve the voltage stability margin of the power system.

[0014] The present invention provides a computer-readable storage medium, wherein the storage medium stores a computer program, and when the computer program is executed by a processor, the voltage stability margin improvement method of the power system is implemented.

[0015] The present invention provides a computer device, comprising a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the processor implements the voltage stability margin improvement method of the above-mentioned power system when executing the program.

[0016] At least one of the above technical solutions adopted by the present invention can achieve the following beneficial effects: In the present invention, when it is necessary to improve the voltage stability margin of the power system, first, the global sensitivity of each interconnection line in the power system is determined, and the target interconnection line participating in the improvement of the voltage stability margin is determined by the global sensitivity of each interconnection line in the power system. Since the global sensitivity represents the degree of influence of the interconnection line on the voltage stability margin of the power system, the target interconnection line is determined by the global sensitivity of each interconnection line in the power system, and the target interconnection line can be effectively determined. In this way, the number of interconnection lines participating in the voltage stability margin modulation can be reduced on the basis of ensuring the effective adjustment of the voltage stability margin, thereby reducing the modulation cost; and the interconnection line active modulation model includes an objective function and voltage constraints such as interconnection line power balance constraints, interconnection line adjustable capacity limit constraints, voltage stability margin improvement constraints and voltage operation level constraints; the objective function is constructed with the goal of minimizing the cost required to adjust the target interconnection line, so that by solving the interconnection line active modulation model, the optimal active power adjustment amount for the target interconnection line can be obtained, ensuring that the cost of adjusting the voltage stability margin of the power system is minimized. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings: Figure 1 A schematic flow chart of a method for improving voltage stability margin of an electric power system provided by the present invention; Figure 2 A schematic flow chart of another method for improving voltage stability margin of an electric power system provided by the present invention; Figure 3 A schematic diagram of the structure of an electric power testing system provided by the present invention; Figure 4 A schematic diagram for comparing the calculation results of a global sensitivity provided by the present invention; Figure 5 A voltage amplitude improvement effect diagram of a method for improving voltage stability margin of an electric power system provided by the present invention; Figure 6 A schematic diagram of a voltage stability margin improving device for a power system provided by the present invention; Figure 7 A schematic diagram of a computer device for realizing a method for improving voltage stability margin of an electric power system provided by the present invention. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the specific embodiments of the present invention and the corresponding drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0019] The execution subject of the method for improving the voltage stability margin of the power system in the present invention may be a server set on the business platform, or a device such as a desktop computer, a laptop computer, etc. that can execute the solution of the present invention. For the convenience of description, the following description is based on the server as the execution subject.

[0020] The technical solutions provided by various embodiments of the present invention are described in detail below in conjunction with the accompanying drawings.

[0021] Figure 1 The present invention is a flow chart of a method for improving voltage stability margin of a power system, which specifically includes the following steps: S101, when the voltage stability margin of the power system is less than the stability threshold, calculating the global sensitivity of each tie line in the power system; the global sensitivity represents the influence of the corresponding tie line on the voltage stability margin of the power system.

[0022] The server can monitor the voltage stability margin in the power system in real time, and when the voltage stability margin of the power system is less than the stability threshold, the voltage stability margin of the power system is increased.

[0023] The voltage stability margin of the power system can be calculated using the continuous power flow method. For example, the voltage stability limit power of the power system is , the current operating power of the power system is , then the voltage stability margin ; The stability threshold can be a safe operation threshold of the power system.

[0024] Optionally, calculating the global sensitivity of each tie line in the power system includes: obtaining the active power and voltage stability margin of each tie line in a historical time period; and determining the global sensitivity of each tie line according to the active power and voltage stability margin of each tie line in the historical time period.

[0025] The historical time period may be a preset time period before the current moment. For example, the historical time period may be within 5 minutes before the current moment.

[0026] The active power and voltage stability margin of each tie line at each moment in the historical time period can be obtained. The active power and voltage stability margin of each tie line at each moment in the historical time period are used as input and substituted into the calculation formula of the global sensitivity to obtain the global sensitivity of each tie line in the power system.

[0027] Preferably, the calculation formula of global sensitivity includes: (1); in, is the global sensitivity matrix, and the element values ​​in the global sensitivity matrix represent the global sensitivity of each tie line. , is the number of tie lines; Represents the voltage stability margin, express The transpose of express The Gram matrix of , express The inverse of and Respectively i The contact line and j Active power of the interconnection lines; , yes , , express The transpose of Active power The probability distribution function of represents the bias term, for dimension and all elements are Column vector of ; Represents the product of corresponding matrix elements.

[0028] In an exemplary embodiment, the process of constructing the global sensitivity calculation formula includes: S1, obtain the active power X and voltage stability margin of the tie line y The sensitivity function between , as shown in formula (2).

[0029] (2); in, .

[0030] S2, select a function h ( x ) Fitting sensitivity function f (X ): (3); in, H is a Hilbert space, m ( X ) is the fitting function defined in the Hilbert space.

[0031] S3, m ( X ) is further rewritten into the form of kernel function, as shown in formula (4).

[0032] (4); in, express The Gram matrix of , is the element in active power X, and are the active powers of the ith tie line and the jth tie line respectively, express The inverse of yes K , , express The transpose of .

[0033] S4, analyzed by ANOVA Expand it and we get formula (5).

[0034] (5); in, represents the bias term, for dimension and all elements are Column vector of ; Represents the product of corresponding matrix elements.

[0035] S5, therefore, combined with formula (5), formula (4) can be written as: (6); in, express The transpose and sum symbol of Satisfaction with all of i and j To sum, for example, when When , the terms to be summed include: hour, ;when hour, ;when hour, .

[0036] S6, calculate the global sensitivity expression of the Quasi-Monte Carlo sequence (Sobol'): (7); in, For I The interpolation function for the index , , for The transpose of express The variance of express The variance of .

[0037] S102, determining a target tie line that participates in improving the voltage stability margin according to the global sensitivity of each tie line.

[0038] There can be multiple target contact lines.

[0039] In the power system, some tie lines have relatively little impact on the voltage stability margin or node voltage of the receiving system, that is, the value of the global sensitivity obtained by S101 is small, so the number of tie lines that need to be adjusted can be reduced to further reduce the calculation complexity and cost.

[0040] For example, the tie line with a global sensitivity greater than a sensitivity threshold is determined as the target tie line, that is, the tie line corresponding to the smaller global sensitivity does not participate in the voltage stability margin improvement process.

[0041] In practical applications, the transmission power of some interconnection lines in the power system may be close to the transmission limit. Therefore, its transmission power limit does not allow this part of the interconnection lines to participate in the adjustment of the voltage stability margin, which further reduces the calculation complexity and the cost of improving the voltage stability margin. Therefore, before determining the target interconnection lines participating in the improvement of the voltage stability margin based on the global sensitivity of each interconnection line, the interconnection lines whose absolute value of the difference between the active power in the power system and the preset power threshold is less than the preset difference can be eliminated, that is, the interconnection lines calculated by the parameter global sensitivity are the interconnection lines that have not been eliminated in the power system.

[0042] Optionally, the global sensitivity of all tie lines in the power system may be calculated, and then tie lines whose absolute value of the difference between the active power in the power system and a preset power threshold is greater than or equal to the preset difference and whose global sensitivity is greater than the sensitivity threshold are determined as target tie lines.

[0043] S103, solving the active power modulation model of the tie line according to the operating parameters of the target tie line to obtain the active power adjustment of the target tie line; the active power modulation model of the tie line includes an objective function and voltage constraints such as tie line power balance constraints, tie line adjustable capacity limit constraints, voltage stability margin improvement constraints and voltage operation level constraints; the objective function is constructed with the goal of minimizing the cost required to adjust the target tie line.

[0044] The objective function is: (8); in, is the objective function value, is the number of target contact lines, and Respectively j The active positive adjustment cost coefficient and the active negative adjustment cost coefficient of the target interconnection line; and Respectively j The active positive power adjustment and active negative power adjustment of the target interconnection line.

[0045] It should be noted that each target interconnection line corresponds to an active positive power adjustment amount or an active negative power adjustment amount. The active positive power adjustment amount is a positive number, indicating that the active power amount of the corresponding target interconnection line needs to be increased, and the active negative power adjustment amount is a negative number, indicating that the active power amount of the corresponding target interconnection line needs to be reduced. When the active positive power adjustment amount of the target interconnection line is a positive number, the active negative power adjustment amount of the target interconnection line should be 0; when the active negative power adjustment amount of the target interconnection line is a negative number, the active positive power adjustment amount of the target interconnection line should be 0; when the active positive power adjustment amount and the active negative power adjustment amount of the target interconnection line are both 0, it means that the active power of the target interconnection line is not adjusted.

[0046] The tie line power balance constraint is: (9).

[0047] Formula (9) indicates that the sum of the active power required to be increased and the active power required to be reduced in all target tie lines should be 0.

[0048] The constraints on the adjustable capacity of the tie line are: (10); in, and Respectively j The upper limit and lower limit of active power of the target interconnection line; Before adjustment jThe active power of the target interconnection line.

[0049] The voltage stability margin improvement constraint is: (11); in, is the global sensitivity; is the preset minimum voltage stability margin threshold value; is the current voltage stability margin of the power system; is the compensation factor.

[0050] Voltage constraints such as voltage operating level are: (12); in, and To ensure the safe operation of the power system. i The upper and lower limits of the voltage amplitude of the target tie line; For the i The voltage value of the target interconnection line.

[0051] Therefore, based on the above objective function and various constraints, the active power adjustment amount of each interconnection line is determined; specifically, the active power adjustment amount includes an active positive power adjustment amount or an active negative power adjustment amount; according to the operating parameters of the target interconnection line, the active modulation model of the interconnection line is solved to obtain the active power adjustment amount of each interconnection line, including: substituting the operating parameters of the target interconnection line into the objective function and various constraints, and under the condition of satisfying various constraints, determining the active positive power adjustment amount or the active negative power adjustment amount of the target interconnection line with the goal of minimizing the objective function.

[0052] S104, adjusting the power of the target interconnection line by adjusting the active power of the target interconnection line to improve the voltage stability margin of the power system.

[0053] The power of the target interconnection line is adjusted by the active power adjustment amount of the target interconnection line. After the target interconnection line is subjected to active directional modulation, the voltage stability margin of the power system is obtained again, and steps S101-S104 are re-executed to re-adjust the active power of the interconnection line until the adjusted voltage stability margin is greater than or equal to the stability threshold, thereby completing the voltage stability margin improvement strategy.

[0054] In this invention, a data-driven global sensitivity calculation method is first proposed to determine the effective voltage stability margin improvement reference tie line (target tie line); further, an active modulation model of the tie line based on voltage stability margin improvement is constructed, and the objectives such as the operability of the control measures and the control cost are comprehensively considered, and the control capacity of the controllable resources and the power balance and other operating constraints are taken into account to study the voltage stability margin improvement method. Compared with the traditional method, it has a better stability margin improvement effect, and is completely based on the measurement data calculation, avoiding system modeling, and thus has a high practical application value.

[0055] In an exemplary embodiment, the present invention also provides a method for improving voltage stability margin of a power system, such as Figure 2 As shown, this embodiment includes the following steps: S201, real-time monitoring of voltage stability margin of power system K 0.

[0056] S202, judgment K 0< K req .

[0057] Among them, K 0 is less than the stability threshold K req If yes, execute step S202; otherwise, continue to execute step S201.

[0058] S203, obtaining tie line operation parameter data, collecting phasor measurement unit data, and setting initial control parameters.

[0059] S204, performing global sensitivity calculation of each tie line.

[0060] The interconnection lines participating in the voltage stability margin modulation are determined according to the global sensitivity of each interconnection line.

[0061] S205, Iteration k max times, solve the active power modulation model of the interconnection line.

[0062] Among them, according to the operating parameters of the tie line participating in the voltage stability margin modulation, the tie line active modulation model is iterated kmax Solve again to obtain the active power adjustment of each parameter interconnection line.

[0063] S206, uploading the active power adjustment amount of each participating interconnection line to the dispatching center.

[0064] S207, update the adjusted voltage stability margin K .

[0065] S208, judgmentK < K req .

[0066] Among them, K Less than the stability threshold K req When the voltage stability margin improvement process of the power system is re-executed.

[0067] In an exemplary embodiment, Figure 3 As shown in the structural diagram of the power test system, the CENTRAL area in the power test system is a heavy load area, and its power supply is mainly provided by the NORTH area through 5 interconnection lines, namely 4031-4041a, 4031-4041b, 4032-4044, 4032-4042 and 4021-4042. In the receiving end area, the load nodes that are focused on are nodes 1, 2, 3, 4, 5, 41, 42, 43, 46 and 47. In addition to the voltage of each load bus, the voltage levels of buses 1043, 1044, 4044 and 4045 also need to be focused on.

[0068] Under normal system operation, due to the randomness and uncertainty of grid-connected renewable energy output, the system dynamic response also has certain volatility. In order to determine the location of the reference tie line, it is necessary to calculate the global sensitivity of the active power change of each tie line to the voltage stability margin. The calculation results of the global sensitivity are as follows: Figure 4 As shown, Spf represents the true value, Smc represents the existing sensitivity method, Skr The calculation method of the global sensitivity provided by the present invention is shown. The system interconnection line power is adjusted according to the global sensitivity calculation result. The stability margin improvement effect is shown in Table 1.

[0069] Table 1

[0070] The feasibility and effectiveness of the method provided by the present invention in improving the voltage stability margin of the power system are further verified by the interconnection line power adjustment results.

[0071] like Figure 5 As shown, Figure 5 A voltage amplitude improvement effect diagram of a method for improving voltage stability margin of a power system provided by the present invention, according to Figure 5 It can be seen from the observed bus voltage amplitudes before and after the adjustment that the method proposed in the present invention can be applied to improving the system voltage stability margin and ensuring voltage stability.

[0072] When applying the voltage stability margin improvement method of the power system provided by the present invention, it is not necessary to Figure 1The steps are executed in the order shown. The specific execution order of the steps can be determined according to needs, and the present invention does not limit this.

[0073] The above is a method for improving the voltage stability margin of a power system provided by one or more embodiments of the present invention. Based on the same idea, the present invention also provides a corresponding device for improving the voltage stability margin of a power system, such as Figure 6 shown.

[0074] Figure 6 A schematic diagram of a voltage stability margin improvement device for a power system provided by the present invention, the device 600 comprises: A calculation module 601 is used to calculate the global sensitivity of each tie line in the power system when the voltage stability margin of the power system is less than the stability threshold; the global sensitivity indicates the influence of the corresponding tie line on the voltage stability margin of the power system; A first determination module 602 is used to determine a target tie line for improving voltage stability margin according to the global sensitivity of each tie line; The second determination module 603 is used to solve the tie line active modulation model according to the operating parameters of the target tie line to obtain the active power adjustment amount of the target tie line; the tie line active modulation model includes an objective function and tie line power balance constraints, tie line adjustable capacity limit constraints, voltage stability margin improvement constraints and voltage operation level and other voltage constraints; the objective function is constructed with the goal of minimizing the cost required to adjust the target tie line; The adjustment module 604 is used to adjust the power of the target interconnection line through the active power adjustment amount of the target interconnection line to improve the voltage stability margin of the power system.

[0075] For the specific definition of the voltage stability margin improvement device of the power system, please refer to the definition of the voltage stability margin improvement method of the power system mentioned above, which will not be repeated here. Each module in the above-mentioned voltage stability margin improvement device of the power system can be implemented in whole or in part by software, hardware and a combination thereof. The above-mentioned modules can be embedded in or independent of the processor in the computer device in the form of hardware, or can be stored in the memory of the computer device in the form of software, so that the processor can call and execute the operations corresponding to the above modules.

[0076] The present invention also provides a computer-readable storage medium, which stores a computer program, which can be used to execute the above Figure 1 A method for improving the voltage stability margin of a power system is provided.

[0077] The present invention also provides Figure 7 The structural diagram of the computer device shown in FIG. Figure 7As shown in the figure, at the hardware level, the computer device includes a processor, an internal bus, a network interface, a memory, and a non-volatile memory, and may also include other hardware required for the business. The processor reads the corresponding computer program from the non-volatile memory into the memory and then runs it to achieve the above Figure 1 A method for improving the voltage stability margin of a power system is provided.

[0078] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided by the present invention can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory or optical memory, etc. Volatile memory can include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM).

[0079] The technical features of the above embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of the present invention.

Claims

1. A method for improving voltage stability margin of a power system, characterized in that: include: When the voltage stability margin of the power system is less than the stability threshold, the global sensitivity of each tie line in the power system is calculated; The global sensitivity represents the influence degree of the corresponding tie line on the voltage stability margin of the power system; Determining a target tie line for improving the voltage stability margin according to the global sensitivity of each tie line; According to the operating parameters of the target tie line, the tie line active modulation model is solved to obtain the active power adjustment of the target tie line; the tie line active modulation model includes an objective function and tie line power balance constraints, tie line adjustable capacity limit constraints, voltage stability margin improvement constraints, voltage operation level and other voltage constraints; the objective function is constructed with the goal of minimizing the cost required to adjust the target tie line; The power of the target tie line is adjusted by adjusting the active power of the target tie line to improve the voltage stability margin of the power system.

2. The method according to claim 1, characterized in that The calculating of the global sensitivity of each tie line in the power system comprises: Obtaining the active power and voltage stability margin of each tie line in a historical time period; The global sensitivity of each of the tie lines is determined according to the active power and voltage stability margin of each of the tie lines in a historical time period.

3. The method according to claim 2, characterized in that The calculation formula of the global sensitivity includes: ； in, is the global sensitivity matrix, and the element values ​​in the global sensitivity matrix represent the global sensitivity of each tie line. , is the number of tie lines; Represents the voltage stability margin, express The transpose of express The Gram matrix of , express The inverse of and Respectively i The contact line and j Active power of the interconnection lines; , yes , , express The transpose of Active power The probability distribution function of represents the bias term, for dimension and all elements are Column vector of ; Represents the product of corresponding matrix elements.

4. The method according to claim 1, characterized in that Determining the target tie line participating in improving the voltage stability margin according to the global sensitivity of each tie line includes: A tie line whose global sensitivity is greater than a sensitivity threshold is determined as the target tie line.

5. The method according to claim 1, characterized in that Before determining the target tie line participating in improving the voltage stability margin according to the global sensitivity of each tie line, the method further includes: The tie lines in the power system whose absolute value of the difference between the active power and the preset power threshold is less than the preset difference are eliminated.

6. The method according to claim 1, characterized in that The objective function is: ； in, is the objective function value, is the number of target contact lines, and Respectively j The active positive adjustment cost coefficient and the active negative adjustment cost coefficient of the target interconnection line; and Respectively j The active positive power adjustment and the active negative power adjustment of the target interconnection line; The tie line power balance constraint condition is: ； The tie line adjustable capacity constraint condition is: ； in, and Respectively j The upper limit and lower limit of active power of the target interconnection line; Before adjustment j Active power of the target interconnection line; The voltage stability margin improvement constraint condition is: ； in, is the global sensitivity; is the preset minimum voltage stability margin threshold value; is the current voltage stability margin of the power system; is the compensation factor; The voltage constraints such as the voltage operating level are: ； in, and To ensure the safe operation of the power system. i The upper and lower limits of the voltage amplitude of the target tie line; For the i The voltage value of the target interconnection line.

7. The method according to claim 6, characterized in that The active power adjustment includes an active positive power adjustment or an active negative power adjustment; solving the active power modulation model of the tie line according to the operating parameters of the target tie line to obtain the active power adjustment of the target tie line includes: Substituting the operating parameters of the target tie line into the objective function and various constraints, and determining the active positive power adjustment amount or the active negative power adjustment amount of the target tie line with the goal of minimizing the objective function while satisfying various constraints.

8. A voltage stability margin improvement device for an electric power system, characterized in that: include: A calculation module, used for calculating the global sensitivity of each tie line in the power system when the voltage stability margin of the power system is less than the stability threshold; The global sensitivity represents the influence degree of the corresponding tie line on the voltage stability margin of the power system; A first determination module is used to determine a target tie line participating in improving the voltage stability margin according to the global sensitivity of each tie line; The second determination module is used to solve the tie line active modulation model according to the operating parameters of the target tie line to obtain the active power adjustment amount of the target tie line; the tie line active modulation model includes an objective function and tie line power balance constraints, tie line adjustable capacity limit constraints, voltage stability margin improvement constraints and voltage operation level and other voltage constraints; the objective function is constructed with the goal of minimizing the cost required to adjust the target tie line; The adjustment module is used to adjust the power of the target tie line through the active power adjustment amount of the target tie line to improve the voltage stability margin of the power system.

9. A computer-readable storage medium, characterized in that: The storage medium stores a computer program, and when the computer program is executed by a processor, the method according to any one of claims 1 to 7 is implemented.

10. A computer device, characterized in that: The method comprises a memory, a processor and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the method according to any one of claims 1 to 7 is implemented.

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