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

Abstract

The present invention discloses a method, device, medium and equipment for improving the voltage stability margin of a power system, which relates to the technical field of power system operation and maintenance. When the voltage stability margin of the power system is less than the stability threshold, calculate 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; determine the target tie line participating in the improvement of the voltage stability margin according to the global sensitivity of each tie line; solve 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 amount of the target tie line; 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. This method can improve the voltage stability margin of the power system under active power directional modulation with less cost based on existing coordinated resources.

Description

Technical Field

[0001] The present invention relates to the technical field of power system operation and maintenance, and particularly to a method, device, medium and equipment for improving the 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 power voltage support capacity of the system gradually decreases, exacerbating the complexity of voltage stability problem analysis. Since the voltage stability degree of a power system is closely related to reactive power, generally, improving the transient voltage stability margin takes optimizing reactive power distribution and enhancing the voltage stability margin as the primary goal. However, there is also a strong coupling relationship between the system voltage stability and active power. Moreover, for large transmission networks, when the receiving-end reactive power sources are limited, the transmission of tie-line active power has a certain regulatory potential for improving the voltage stability margin.

[0003] However, the research on improving the voltage stability margin by active power in the prior art is relatively scarce. On the other hand, the formulation of preventive control measures requires a certain economic cost. Especially for new-generation synchronous condensers and STATCOMs and other devices, the trade-off between safety and economy often needs to be solved in the operation planning stage.

[0004] Therefore, there is an urgent need in the prior art for a method to improve the voltage stability margin of a power system under active power directional modulation with less cost. Summary of the Invention

[0005] Based on this, in view of the above technical problems, it is necessary to provide a method, device, medium and equipment for improving the voltage stability margin of a power system, which can improve the voltage stability margin of a power system under active power directional modulation with less cost based on existing coordinated resources.

[0006] The present invention adopts the following technical solutions:

[0007] The present invention provides a method for improving the voltage stability margin of a power system, including:

[0008] When the voltage stability margin of the power system is less than the stability threshold, calculate 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;

[0009] Determine the target tie-line participating in improving the voltage stability margin according to the global sensitivity of each tie-line;

[0010] Solve the active power modulation model of the target tie line according to the operating parameters of the target tie line to obtain the active power adjustment amount of the target tie line; the active power modulation model of the tie line includes an objective function and voltage constraint conditions such as a tie line power balance constraint condition, a tie line adjustable capacity limit constraint condition, a voltage stability margin improvement constraint condition, and a voltage operation level; the objective function is constructed with the goal of minimizing the cost required to adjust the target tie line.

[0011] 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.

[0012] Preferably, calculate the global sensitivity of each tie line in the power system, including:

[0013] Obtain the active power and voltage stability margin of each tie line within the historical time period;

[0014] Determine the global sensitivity of each tie line according to the active power and voltage stability margin of each tie line within the historical time period.

[0015] Preferably, the calculation formula of the global sensitivity includes:

[0016] ;

[0017] Among them, is the global sensitivity matrix, and the element value in the global sensitivity matrix represents the global sensitivity of each tie line, , is the number of tie lines; represents the voltage stability margin, represents transpose; represents Gram matrix of, and , represents inverse; and are the active powers of the i th tie line and the j th tie line respectively; , is column vector of, , represents transpose, is the active power probability distribution function; represents the bias term, is dimensional and all elements are column vector of; Indicates the product of the corresponding elements of the matrix.

[0018] Preferably, according to the global sensitivity of each tie line, determining the target tie lines participating in improving the voltage stability margin includes:

[0019] Determining the tie lines with global sensitivity greater than the sensitivity threshold as the target tie lines.

[0020] Preferably, before determining the target tie lines participating in improving the voltage stability margin according to the global sensitivity of each tie line, the method further includes:

[0021] Eliminating 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.

[0022] Preferably, the objective function is:

[0023] ;

[0024] Wherein, is the objective function value, is the number of target tie lines, and are respectively the active positive adjustment cost coefficient and the active negative adjustment cost coefficient of the j th target tie line; and are respectively the active positive power adjustment amount and the active negative power adjustment amount of the j th target tie line;

[0025] The tie line power balance constraint condition is:

[0026] ;

[0027] The tie line adjustable capacity limit constraint condition is:

[0028] ;

[0029] Wherein, and are respectively the upper limit value and the lower limit value of the active power of the j th target tie line; is the active power of the j th target tie line before adjustment;

[0030] The voltage stability margin improvement constraint condition is:

[0031] ;

[0032] Wherein, 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;

[0033] The voltage operation level and other voltage constraint conditions are:

[0034] ;

[0035] Among them, and are respectively the upper limit and the lower limit of the voltage amplitude of the i th target tie line to ensure the safe operation of the power system; is the i th voltage value of the target tie line.

[0036] Preferably, 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 tie line, the active power modulation model of the tie line is solved to obtain the active power adjustment amount of the target tie line, including:

[0037] Substitute the operating parameters of the target tie line into the objective function and each constraint condition. Under the condition of satisfying each constraint condition, with the minimization of the objective function as the goal, determine the active positive power adjustment amount or the active negative power adjustment amount of the target tie line.

[0038] The present invention provides a device for improving the voltage stability margin of a power system, including:

[0039] A calculation module, configured 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 represents the influence degree of the corresponding tie line on the voltage stability margin of the power system;

[0040] A first determination module, configured to determine the target tie line participating in the improvement of the voltage stability margin according to the global sensitivity of each tie line;

[0041] A second determination module, configured to solve 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 amount of the target tie line; the active power modulation model of the tie line includes an objective function and tie line power balance constraint conditions, tie line adjustable capacity limit constraint conditions, voltage stability margin improvement constraint conditions, and voltage operation level and other voltage constraint conditions; the objective function is constructed with the goal of minimizing the cost required to adjust the target tie line;

[0042] An adjustment module, configured 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.

[0043] The present invention provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the method for improving the voltage stability margin of the above-mentioned power system.

[0044] The present invention provides a computer device, including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the program, it implements the method for improving the voltage stability margin of the above-mentioned power system.

[0045] The above at least one technical solution adopted by the present invention can achieve the following beneficial effects:

[0046] In the present invention, when it is necessary to improve the voltage stability margin of a power system, first, the global sensitivity of each tie line in the power system is determined, and the target tie line participating in the improvement of the voltage stability margin is determined through the global sensitivity of each tie line in the power system. Since the global sensitivity represents the influence degree of the tie line on the voltage stability margin of the power system, determining the target tie line based on the global sensitivity of each tie line in the power system can effectively determine the target tie line. In this way, on the basis of ensuring the effective adjustment of the voltage stability margin, the number of tie lines participating in the voltage stability modulation can be reduced, and the modulation cost can be reduced; moreover, the active power modulation model of the tie line includes an objective function and voltage constraint conditions such as tie line power balance constraint conditions, tie line adjustable capacity limit constraint conditions, voltage stability margin improvement constraint conditions, and voltage operation level; the objective function is constructed with the goal of minimizing the cost required to adjust the target tie line. In this way, by solving the active power modulation model of the tie line, the optimal active power adjustment amount for the target tie line can be obtained, ensuring the minimum cost of adjusting the voltage stability margin of the power system. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] The drawings described herein are used to provide a further understanding of the present invention and form a part of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0048] Figure 1 is a schematic flow chart of a method for improving the voltage stability margin of a power system provided by the present invention;

[0049] Figure 2 is a schematic flow chart of another method for improving the voltage stability margin of a power system provided by the present invention;

[0050] Figure 3 is a schematic structural diagram of a power test system provided by the present invention;

[0051] Figure 4 is a schematic diagram for comparing the calculation results of a global sensitivity provided by the present invention;

[0052] Figure 5 Voltage amplitude increase effect diagram of a method for improving voltage stability margin of a power system provided by the present invention;

[0053] Figure 6 Schematic diagram of a device for improving voltage stability margin of a power system provided by the present invention;

[0054] Figure 7 Schematic diagram of a computer device for implementing a method for improving voltage stability margin of a power system provided by the present invention. Detailed implementation manners

[0055] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments of the present invention and the corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0056] The execution subject of the method for improving the voltage stability margin of the power system in the present invention can be a server set up in a service platform, or devices such as a desktop computer or a notebook computer that can execute the solution of the present invention. For the convenience of description, only the server is used as the execution subject for illustration below.

[0057] The technical solutions provided by the embodiments of the present invention will be described in detail below in conjunction with the drawings.

[0058] Figure 1 Schematic diagram of the process of a method for improving the voltage stability margin of a power system in the present invention, specifically including the following steps:

[0059] S101, when the voltage stability margin of the power system is less than the stability threshold, calculate 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.

[0060] The server can monitor the voltage stability margin in the power system in real time. When the voltage stability margin of the power system is less than the stability threshold, the voltage stability margin of the power system is improved.

[0061] Among them, the continuous power flow method can be used to calculate the voltage stability margin of the power system; for example, assume that the limit power of voltage stability in the power system is , and the current operating power of the power system is , then the voltage stability margin ; the stability threshold can be the safe operating threshold of the power system.

[0062] Optionally, calculate the global sensitivity of each tie line in the power system, including: obtaining the active power and voltage stability margin of each tie line within a historical time period; determining the global sensitivity of each tie line according to the active power and voltage stability margin of each tie line within the historical time period.

[0063] The historical time period can be a preset duration before the current moment. For example, the historical time period can be within the past 5 minutes before the current moment.

[0064] The active power and voltage stability margin of each tie line at each moment within the historical time period can be obtained. Taking the active power and voltage stability margin of each tie line at each moment within the historical time period as inputs and substituting them into the calculation formula of the global sensitivity, the global sensitivity of each tie line in the power system can be obtained.

[0065] Preferably, the calculation formula of the global sensitivity includes:

[0066] (1);

[0067] Wherein, is the global sensitivity matrix, and the element value in the global sensitivity matrix represents the global sensitivity of each tie line. , is the number of tie lines; represents the voltage stability margin. represents transpose; represents Gram matrix of, and , represents inverse; and are respectively the active power of the i th tie line and the j th tie line; , is column vector of, , represents transpose, is the active power probability distribution function; represents the bias term, is dimensional and all elements are column vector of; represents the product of the corresponding elements of the matrix.

[0068] In an exemplary embodiment, the construction process of the global sensitivity calculation formula includes:

[0069] S1. Obtain the sensitivity function between the active power X of the tie line and the voltage stability margin y as shown in formula (2).

[0070] (2);

[0071] where

[0072] S2. Select a function h ( x ) to fit the sensitivity function f ( X ):

[0073] (3);

[0074] where H is the Hilbert space, and m ( X ) is the fitting function defined in the Hilbert space.

[0075] S3. Further rewrite m ( X ) into the form of a kernel function, as shown in formula (4).

[0076] (4);

[0077] where represents the Gram matrix of , and , is an element in the active power X, and are the active powers of the i-th tie line and the j-th tie line respectively, represents the inverse of ; is the column vector of K , , represents the transpose of .

[0078] S4. Expand by analysis of variance kernel to obtain formula (5).

[0079] (5);

[0080] where represents the bias term, is a column vector of dimensions with all elements being ; ​​Denotes the product of the corresponding elements of the matrix.

[0081] S5. Thus, combining with formula (5), formula (4) can be written as:

[0082] (6);

[0083] Wherein, Denotes The transpose of, and the summation symbol Denotes the summation over all Satisfying i And j For example, when , the terms of the summation include: when , ; when , ; when , .

[0084] S6. Calculate the global sensitivity expression of the quasi-Monte Carlo sequence (Sobol’):

[0085] (7);

[0086] Wherein, Is the interpolation function I Indexed by , , Is The transpose of, Denotes The variance of, Denotes The variance of.

[0087] S102. Determine the target tie lines participating in improving the voltage stability margin according to the global sensitivities of each tie line.

[0088] There can be multiple target tie lines.

[0089] In the power system, some tie lines have relatively little influence on the voltage stability margin of the receiving-end system or the node voltage, that is, the values of the global sensitivities obtained through S101 are small. Based on this, the number of tie lines to be adjusted can be reduced to further reduce the computational complexity and cost.

[0090] For example, determine the tie lines with global sensitivities greater than the sensitivity threshold as the target tie lines, that is, the tie lines corresponding to smaller global sensitivities do not participate in the process of improving the voltage stability margin.

[0091] In practical applications, the transmission power of some tie lines in the power system may already be close to the transmission limit. Therefore, the transmission power limit does not allow this part of the tie lines to participate in the adjustment of the voltage stability margin, which further reduces the computational complexity and the cost of improving the voltage stability margin. Therefore, before determining the target tie lines participating in the improvement of the voltage stability margin according to the global sensitivity of each tie line, the tie lines with the absolute value of the difference between the active power and the preset power threshold in the power system less than the preset difference can be excluded, that is, the tie lines for which the global sensitivity is calculated are the non-excluded tie lines in the power system.

[0092] Optionally, it can also be to calculate the global sensitivity of all tie lines in the power system, and then determine the tie lines with the absolute value of the difference between the active power and the preset power threshold in the power system greater than or equal to the preset difference and the global sensitivity greater than the sensitivity threshold as the target tie lines.

[0093] S103. Solve 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 amount of the target tie line; the active power modulation model of the tie line includes the objective function and voltage constraint conditions such as the tie line power balance constraint condition, the tie line adjustable capacity limit constraint condition, the voltage stability margin improvement constraint condition, and the voltage operation level; the objective function is constructed with the goal of minimizing the cost required to adjust the target tie line.

[0094] The objective function is:

[0095] (8);

[0096] Wherein, is the objective function value, is the number of target tie lines, and are respectively the positive active power adjustment cost coefficient and the negative active power adjustment cost coefficient of the j th target tie line; and are respectively the positive active power adjustment amount and the negative active power adjustment amount of the j th target tie line.

[0097] It should be noted that each target tie line corresponds to a positive active power adjustment amount or a negative active power adjustment amount. The positive active power adjustment amount is a positive number, indicating the amount of active power that needs to be increased for the corresponding target tie line. The negative active power adjustment amount is a negative number, indicating the amount of active power that needs to be decreased for the corresponding target tie line. When the positive active power adjustment amount of the target tie line is a positive number, the negative active power adjustment amount of the target tie line should be 0; when the negative active power adjustment amount of the target tie line is a negative number, the positive active power adjustment amount of the target tie line should be 0; when both the positive active power adjustment amount and the negative active power adjustment amount of the target tie line are 0, it means that the active power of the target tie line is not adjusted.

[0098] The tie line power balance constraint condition is:

[0099] (9).

[0100] Formula (9) indicates that the sum of the amount of active power that needs to be increased and the amount of active power that needs to be decreased among all target tie lines should be 0.

[0101] The tie line adjustable capacity limit constraint condition is:

[0102] (10);

[0103] Wherein, and are respectively the upper limit value and the lower limit value of the active power of the j th target tie line; is the active power of the j th target tie line before adjustment.

[0104] The voltage stability margin improvement constraint condition is:

[0105] (11);

[0106] Wherein, 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.

[0107] The voltage operation level and other voltage constraint conditions are:

[0108] (12);

[0109] Wherein, and are respectively the iThe upper and lower limits of the voltage amplitude of the target tie line; is the i voltage value of the target tie line.

[0110] Therefore, based on the above objective function and various constraint conditions, determine the active power adjustment amount of each tie line; specifically, the active power adjustment amount includes the positive active power adjustment amount or the negative active power adjustment amount; according to the operating parameters of the target tie line, solve the active power modulation model of the tie line to obtain the active power adjustment amount of each tie line, including: substituting the operating parameters of the target tie line into the objective function and various constraint conditions, and taking the minimization of the objective function as the goal under the condition of satisfying various constraint conditions, determine the positive active power adjustment amount or the negative active power adjustment amount of the target tie line.

[0111] S104, 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.

[0112] Adjust the power of the target tie line through the active power adjustment amount of the target tie line. After the active power directional modulation of the target tie line, re-obtain the voltage stability margin of the power system, and re-execute steps S101 - S104 to re-adjust the active power of the tie line until the adjusted voltage stability margin is greater than or equal to the stability threshold, thus completing the voltage stability margin improvement strategy.

[0113] In the present invention, first, a calculation method based on data-driven global sensitivity is proposed to determine an effective tie line (target tie line) for adjusting the voltage stability margin; further, a tie line active power modulation model for improving the voltage stability margin is constructed, comprehensively considering objectives such as the operability of the control measures and the control cost, taking into account the control capacity of the adjustable resources and operation constraints such as power balance, and studying the method for improving the voltage stability margin. Compared with the traditional method, it has a better effect of improving the stability margin and is completely realized based on the measurement data calculation, avoiding system modeling, so it has high practical application value.

[0114] In an exemplary embodiment, the present invention also provides a method for improving the voltage stability margin of a power system, as Figure 2 shown, this embodiment includes the following steps:

[0115] S201, real-time monitor the voltage stability margin of the power system K 0 .

[0116] S202, judge K 0 < K req .

[0117] Among them, when K 0 less than the stability threshold K req , step S202 is executed; otherwise, step S201 is continued to be executed.

[0118] S203. Obtain the operating parameter data of the tie lines, collect the phasor measurement unit data, and set the initial control parameters.

[0119] S204. Perform the global sensitivity calculation for each tie line.

[0120] Among them, according to the global sensitivity of each tie line, the tie lines participating in the voltage stability margin modulation are determined.

[0121] S205. Iterate k max times to solve the active power modulation model of the tie lines.

[0122] Among them, according to the operating parameters of the tie lines participating in the voltage stability margin modulation, the active power modulation model of the tie lines is iteratively kmax solved for times to obtain the active power adjustment amounts of each tie line participating in the adjustment.

[0123] S206. Upload the active power adjustment amounts of each tie line participating in the adjustment to the dispatching center.

[0124] S207. Update the adjusted voltage stability margin K .

[0125] S208. Judge K < K req .

[0126] Among them, when K less than the stability threshold K req , the voltage stability margin improvement process of the power system is re-executed.

[0127] In an exemplary embodiment, as shown in the structure diagram of the power test system Figure 3 , in the power test system, the CENTRAL area is a heavy load area, and its power supply is mainly provided by the NORTH area through 5 tie lines, namely 4031 - 4041a, 4031 - 4041b, 4032 - 4044, 4032 - 4042, and 4021 - 4042. In the receiving area, the key load nodes are nodes 1, 2, 3, 4, 5, 41, 42, 43, 46, and 47. In addition to the voltages of each load bus, the voltage levels of buses 1043, 1044, 4044, and 4045 also need to be focused on.

[0128] Under normal operating conditions of the system, due to the randomness and uncertainty of the output of grid-connected new energy, the dynamic response of the system also has a certain degree of volatility. To determine the position of the participating tie line, it is necessary to calculate the global sensitivity of the active power change of each tie line to the voltage stability margin respectively. The calculation results of the global sensitivity are as Figure 4 shown, Spf represents the true value, Smc represents the existing sensitivity method, Skr represents the calculation method of the global sensitivity provided by the present invention. By adjusting the power of the system tie line according to the calculation results of the global sensitivity, the improvement effect of the stability margin is shown in Table 1.

[0129] Table 1

[0130]

[0131] The adjustment result of the tie line power further verifies the feasibility and effectiveness of the method provided by the present invention in improving the voltage stability margin of the power system.

[0132] As Figure 5 shown, Figure 5 is the voltage amplitude improvement effect diagram of a method for improving the voltage stability margin of a power system provided by the present invention. According to the voltage amplitudes of each observed bus before and after adjustment shown in Figure 5 , it can be seen that the method proposed by the present invention can be applied to improve the voltage stability margin of the system and ensure voltage stability.

[0133] When applying the method for improving the voltage stability margin of the power system provided by the present invention, it is not necessary to execute according to the order of the steps shown in Figure 1 . The specific execution order of each step can be determined according to needs, and the present invention does not limit this.

[0134] The above is the 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, as Figure 6 shown.

[0135] Figure 6 is a schematic diagram of a device for improving the voltage stability margin of a power system provided by the present invention. The device 600 includes:

[0136] A calculation module 601, configured 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 represents the influence degree of the corresponding tie line on the voltage stability margin of the power system;

[0137] A first determination module 602, configured to determine the target tie line participating in improving the voltage stability margin according to the global sensitivity of each tie line;

[0138] A second determination module 603, configured to solve a tie-line active power modulation model according to the operating parameters of a target tie-line, so as to obtain an active power adjustment amount of the target tie-line; the tie-line active power modulation model includes an objective function and voltage constraint conditions such as a tie-line power balance constraint condition, a tie-line adjustable capacity limit constraint condition, a voltage stability margin improvement constraint condition, and a voltage operating level; the objective function is constructed with the goal of minimizing the cost required to adjust the target tie-line.

[0139] An adjustment module 604, configured to adjust 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.

[0140] For the specific limitations of the voltage stability margin improvement device of the power system, reference may be made to the limitations of the voltage stability margin improvement method of the power system in the foregoing text, which will not be elaborated 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 their combination. The above-mentioned modules can be embedded in or independent of a processor in a computer device in the form of hardware, or stored in a memory in a computer device in the form of software, so that the processor can call and execute the operations corresponding to the above-mentioned modules.

[0141] The present invention also provides a computer-readable storage medium, which stores a computer program, and the computer program can be used to execute the above Figure 1 provided voltage stability margin improvement method of the power system.

[0142] The present invention also provides Figure 7 a schematic structural diagram of the computer device shown in, as Figure 7 shown, at the hardware level, the computer device includes a processor, an internal bus, a network interface, a memory, and a non-volatile memory. Of course, other hardware required for other services may also be included. The processor reads the corresponding computer program from the non-volatile memory into the memory and then runs it to implement the above Figure 1 provided voltage stability margin improvement method of the power system.

[0143] Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be completed by instructing relevant hardware through a computer program. 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 methods. Among them, any reference to a memory, storage, database, or other medium used in the embodiments provided by the present invention can include at least one of non-volatile and volatile memories. 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. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc.

[0144] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, 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, it should be considered to be within the scope recorded by 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; Adjusting the power of the target tie line by adjusting the active power of the target tie line to improve the voltage stability margin of the power system; The calculation formula of the global sensitivity includes: Among them, S I is the global sensitivity matrix, and the element values ​​in the global sensitivity matrix represent the global sensitivity of each tie line. d is the number of tie lines; y is the voltage stability margin of the tie lines, T represents the transpose of y; K represents the d×d Gram matrix, and K i,j =K(x i ,x j ), K -1 represents the inverse of K; x i and x j are the active powers of the ith tie line and the jth tie line respectively; Γ i =∫k(x i )k(x i ) T dμ i (x i ), k(x i ) is the column vector of K, 0≤i≤d, k(x i ) T represents k(x i ), μ i (x i ) is the active power x i The probability distribution function of ; M represents the bias term, M is a 1×d-dimensional column vector with all elements being 1; ⊙ represents the product of the corresponding elements of the matrix.

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 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.

4. 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.

5. The method according to claim 1, characterized in that The objective function is: Where C is the objective function value, N is the number of target contact lines, and are respectively the active positive adjustment cost coefficient and the active negative adjustment cost coefficient of the jth target tie line; and are respectively the active positive power adjustment amount and the active negative power adjustment amount of the jth target tie line; The tie line power balance constraint condition is: The tie line adjustable capacity constraint condition is: in, and are respectively the upper limit value and the lower limit value of the active power of the jth target tie line; To adjust the active power of the jth target tie line before; The voltage stability margin improvement constraint condition is: Among them, S I is the global sensitivity; K req is the preset minimum voltage stability margin threshold value; K0 is the current voltage stability margin of the power system; γ is the compensation factor; The voltage constraints such as the voltage operating level are: in, and are the upper and lower limits of the voltage amplitude of the i-th target tie line to ensure the safe operation of the power system; U i is the voltage value of the i-th target tie line.

6. The method according to claim 5, 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.

7. A voltage stability margin improvement device for a 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; The calculation formula of the global sensitivity includes: Among them, S I is the global sensitivity matrix, and the element values ​​in the global sensitivity matrix represent the global sensitivity of each tie line. d is the number of tie lines; y is the voltage stability margin of the tie lines, T represents the transpose of y; K represents the d×d Gram matrix, and K i,j =K(x i ,x j ), K -1 represents the inverse of K; x i and x j are the active powers of the ith tie line and the jth tie line respectively; Γ i =∫k(x i )k(x i ) T dμ i (x i ), k(x i ) is the column vector of K, 0≤i≤d, k(x i ) T represents k(x i ), μ i (x i ) is the active power x i The probability distribution function of ; M represents the bias term, M is a 1×d-dimensional column vector with all elements being 1; ⊙ represents the product of the corresponding elements of the matrix; 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.

8. 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 6 is implemented.

9. 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 6 is implemented.

Images