Low-frequency oscillation control methods, devices, electronic equipment and storage media

Abstract

This invention provides a low-frequency oscillation control method, apparatus, electronic device, and storage medium. The method relates to the field of power system detection technology and includes: inputting data to be processed into at least one controller to obtain a first identification result output by each controller; the data to be processed is generated by a low-frequency oscillation mode of the power system; based on the first identification results output by each controller, determining the distance between each first identification result and a preset identification result of each controller; based on the distances corresponding to each controller, determining a target controller from among the controllers; the target controller is used to control the data to be processed within a target range. The method provided by this invention achieves the control of the data to be processed within a target range, improving the control effect of the data and thus enhancing the control performance of the power system.

Description

Technical Field

[0001] This invention relates to the field of power system detection technology, and in particular to a low-frequency oscillation control method, device, electronic equipment, and storage medium. Background Technology

[0002] With the development of power technology, power systems are becoming increasingly complex, and low-frequency oscillations are gradually becoming one of the main safety factors in power systems. Currently, the control of low-frequency oscillations in power systems with wind power integration is an urgent problem to be solved.

[0003] In related technologies, a single controller is used to control low-frequency oscillations in power systems, stabilizing the voltage within a target range. However, due to the complexity of low-frequency oscillations in actual power systems, using a single controller is unlikely to achieve satisfactory control results. Summary of the Invention

[0004] This invention provides a low-frequency oscillation control method, device, electronic device, and storage medium to overcome the shortcomings of poor control performance in the prior art and to control the data to be processed within a better target range.

[0005] This invention provides a low-frequency oscillation control method, the method comprising:

[0006] The data to be processed is input into at least one controller to obtain the first identification result output by each controller; the data to be processed is generated by the low-frequency oscillation mode of the power system.

[0007] Based on the first identification result output by each controller, the distance between each first identification result and the preset identification result of each controller is determined respectively;

[0008] Based on the distances corresponding to each controller, a target controller is determined from each controller; the target controller is used to control the data to be processed within a target range.

[0009] According to a low-frequency oscillation control method provided by the present invention, determining a target controller from among the controllers based on the distances corresponding to each controller includes:

[0010] The distance corresponding to each controller is compared with the preset threshold corresponding to each controller to determine the judgment result;

[0011] Based on the judgment results corresponding to each controller, the target controller is determined from each controller.

[0012] According to a low-frequency oscillation control method provided by the present invention, determining a target controller from among the controllers based on the judgment results corresponding to each controller includes:

[0013] If the judgment result corresponding to each controller is less than the preset threshold, the first identification result output by each controller is input into the switching function for calculation to determine the performance index corresponding to each controller.

[0014] Based on the performance indicators corresponding to each controller, the target performance indicators are determined;

[0015] Based on the target performance indicators, a target controller is determined from among the controllers.

[0016] According to a low-frequency oscillation control method provided by the present invention, the controller includes at least one of the following: an iterative identification linear controller, a nonlinear controller including nonlinear increments, a nonlinear controller not including nonlinear increments, and a nonlinear controller based on the square term of the nonlinear increments; wherein, the nonlinear controller based on the square term of the nonlinear increments is expressed by formula (1):

[0017] A(z -1 )y(k+1)=B(z -1 u(k) + v[x(k-1)] + Δv[x(k)] 2 (1)

[0018] Among them, z -1 Denotes the delay operator, A(z) -1 B(z) represents the set of parameters for the output data added to the delay operator. -1 Let represent the set of parameters of the input data with the delay operator added; y(k+1) represent the output data at the next time step, k represents the k-th time step, u(k) represent the input data, x(k) represent the data vector, v[x(k-1)] represents the higher-order smooth nonlinear function, and Δv[x(k)] represents the higher-order smooth nonlinear function. 2 This represents the squared term of the nonlinear increment.

[0019] According to a low-frequency oscillation control method provided by the present invention, the step of determining the distance between each first identification result and a preset identification result of each controller based on the first identification result output by each controller includes:

[0020] Based on the first identification result output by each controller, the distance between each first identification result and the preset identification result of each controller is calculated.

[0021] According to the low-frequency oscillation control method provided by the present invention, the switching function is expressed by formula (2):

[0022]

[0023] Where i represents the i-th controller, k represents the k-th time, and a i (l) represents the dead-zone function. Δ represents the boundary of the nonlinear increment Δv[x(k)], e i (l) represents the error value calculated using model i, w(l-1) represents the data vector at time l-1, c represents a constant, N is a positive integer, and l is a positive integer.

[0024] The present invention also provides a low-frequency oscillation control device, the device comprising:

[0025] An identification module is used to input the data to be processed into at least one controller and determine the first identification result output by each controller; the data to be processed is generated by a low-frequency oscillation mode of a power system.

[0026] The first determining module determines the distance between each first identification result and the preset identification result of each controller based on the first identification result output by each controller.

[0027] The second determining module is used to determine a target controller from among the controllers based on the distances corresponding to each controller; the target controller is used to control the data to be processed within a target range.

[0028] The present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the low-frequency oscillation control method as described above.

[0029] The present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the low-frequency oscillation control method as described above.

[0030] The present invention also provides a computer program product, including a computer program that, when executed by a processor, implements the low-frequency oscillation control method as described above.

[0031] The low-frequency oscillation control method, apparatus, electronic device, and storage medium provided by the present invention input the data to be processed into at least one controller to obtain the first identification result output by each controller; then, based on the first identification result output by each controller, the distance between each first identification result and the preset identification result of each controller is determined, and a target controller is determined from among the controllers. This achieves the control of the data to be processed within the target range, improves the control effect of the data, and thus improves the control performance of the power system. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0033] Figure 1 This is one of the flowcharts of the low-frequency oscillation control method provided by the present invention;

[0034] Figure 2 This is the second flowchart of the low-frequency oscillation control method provided by the present invention;

[0035] Figure 3 This is the third flowchart of the low-frequency oscillation control method provided by the present invention;

[0036] Figure 4 This is a schematic diagram of the switching control sequence provided by the present invention;

[0037] Figure 5 This is a schematic diagram showing the result of the low-frequency oscillation control method of the present invention;

[0038] Figure 6 This is a schematic diagram of the low-frequency oscillation control device provided by the present invention;

[0039] Figure 7 This is a schematic diagram of the structure of the electronic device provided by the present invention. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0041] The low-frequency oscillation control method provided by the present invention will be described in detail below with reference to the accompanying drawings, through some embodiments and application scenarios.

[0042] This invention provides a low-frequency oscillation control method applicable to control scenarios involving low-frequency oscillations in power systems connected to wind power. The method involves inputting data to be processed into at least one controller, obtaining a first identification result output by each controller; the data to be processed is generated by a low-frequency oscillation mode of the power system; based on the first identification results output by each controller, the distance between each first identification result and a preset identification result of each controller is determined; based on the distances corresponding to each controller, a target controller is determined from among the controllers; the target controller is used to control the data to be processed within a target range. The method provided by this invention achieves the control of the data to be processed within a target range, improving the control effect of the data and thus enhancing the control performance of the power system.

[0043] The following is combined Figures 1-5 The low-frequency oscillation control method of the present invention is described.

[0044] Figure 1 This is one of the flowcharts illustrating the low-frequency oscillation control method provided by the present invention, such as... Figure 1 As shown, the method includes 101-103, wherein:

[0045] Step 101: Input the data to be processed into at least one controller to obtain the first identification result output by each controller; the data to be processed is generated by the low-frequency oscillation mode of the power system.

[0046] It should be noted that the low-frequency oscillation control method provided by this invention is applicable to control scenarios of low-frequency oscillations when wind power is connected to the power system. The executing entity of this method can be a low-frequency oscillation control device, such as an electronic device, or a control module in the low-frequency oscillation control device for executing the low-frequency oscillation control method.

[0047] Specifically, the data to be processed generated by the low-frequency oscillation mode of the power system is input into at least one controller to obtain the first identification result output by each controller; wherein, the data to be processed is generated by the low-frequency oscillation mode of the power system, that is, the data to be processed has low-frequency oscillation characteristics; the data to be processed is data outside the target range, for example, the data to be processed is voltage data or current data outside the target range; the first identification result can be data outside the target range or data within the target range.

[0048] Step 102: Based on the first identification result output by each controller, determine the distance between each first identification result and the preset identification result of each controller.

[0049] Specifically, a preset identification result is preset for each controller, and the distance between the first identification result of each controller and the preset identification result corresponding to each controller is determined based on the first identification result output by each controller.

[0050] Step 103: Based on the distance corresponding to each controller, determine the target controller from each controller; the target controller is used to control the data to be processed within the target range.

[0051] Specifically, based on the distance between the first identification result of each controller and the preset identification result of each controller, a target controller capable of controlling the data to be processed within the target range is determined.

[0052] The low-frequency oscillation control method provided by the present invention inputs the data to be processed into at least one controller to obtain the first identification result output by each controller; then, based on the first identification result output by each controller, the distance between each first identification result and the preset identification result of each controller is determined, and a target controller is determined from each controller. This achieves the control of the data to be processed within the target range, improves the control effect of the data, and thus improves the control performance of the power system.

[0053] Optionally, the controller includes at least one of the following: an iterative identification linear controller, a nonlinear controller including nonlinear increments, a nonlinear controller not including nonlinear increments, and a nonlinear controller based on the square of the nonlinear increment; wherein the nonlinear controller based on the square of the nonlinear increment is represented by formula (1):

[0054] A(z -1 )y(k+1)=B(z -1 u(k) + v[x(k-1)] + Δv[x(k)] 2 (1)

[0055] Among them, z -1 Denotes the delay operator, A(z) -1 B(z) represents the set of parameters for the output data added to the delay operator. -1 Let represent the set of parameters of the input data to be processed with the delay operator added; y(k+1) represent the output data at the next time step, k represents the k-th time step; u(k) represent the input data to be processed; x(k) represent the data vector; v[x(k-1)] represents the higher-order smooth nonlinear function; Δv[x(k)] represents the higher-order smooth nonlinear function. 2 This represents the squared term of the nonlinear increment.

[0056] Specifically, the data to be processed is input into an iterative identification linear controller, a nonlinear controller including nonlinear increments, a nonlinear controller without nonlinear increments, and a nonlinear controller based on the square of the nonlinear increment, respectively. The iterative identification linear controller is used to calculate the data to be processed, and the identification result output by the iterative identification linear controller is obtained. The nonlinear controller including nonlinear increments, the nonlinear controller without nonlinear increments, and the nonlinear controller based on the square of the nonlinear increment are used to perform parameter identification on the data to be processed by estimating the nonlinear increments, and the identification results output by the nonlinear controller including nonlinear increments, the nonlinear controller without nonlinear increments, and the nonlinear controller based on the square of the nonlinear increment are obtained, respectively.

[0057] It should be noted that this invention uses a power system identification model structure for closed-loop identification. A typical single-input single-output nonlinear dynamic system is represented by the following formula (3), i.e.

[0058] y(k+1)=f[y(k),y(k-1),…,y(kn s +1),u(k),u(k-1),…,u(km s (3)

[0059] Where u(k)∈R, y(k)∈R, k represents time k, u(k) represents the input data at time k, y(k) represents the output data at time k, f(·)∈R, f(·) represents a continuously differentiable nonlinear function, and n s and m s This indicates the order of a single-input, single-output nonlinear dynamic system.

[0060] Expanding equation (3) at the origin using Taylor expansion, we obtain equation (4), which is...

[0061]

[0062] Among them, a i and b j Let x(k) represent the first-order coefficients at the origin, and x(k) represent the data vector, x(k) = [y(k), ..., y(k+1-n). s ),u(k),…,u(km s )] T v[x(k)] represents a higher-order smooth nonlinear function, i.e., in the unmodeled dynamics, n s and m s This indicates the order of a single-input, single-output nonlinear dynamic system.

[0063] In practice, v[x(k)] consists of two parts: the previous value v[x(k-1)] and the nonlinear increment Δv[x(k)], which can be expressed by formula (5), i.e.

[0064] v[x(k)]=v[x(k-1)]+Δv[x(k)] (5)

[0065] Therefore, when the unit delay operator z is added... -1 Then, the system represented by formula (4) can be further represented by formula (6), that is, the nonlinear controller including nonlinear increments can be expressed as:

[0066] A(z -1 )y(k+1)=B(z -1 u(k)+v[x(k-1)]+Δv[x(k)] (6)

[0067] Among them, z -1 Denotes the delay operator, A(z) -1 B(z) represents the set of parameters for the output data added to the delay operator. -1 ) represents the set of parameters of the input data to be added to the delay operator, y(k+1) represents the output data of the next time step, k represents the kth time step, u(k) represents the input data, v[x(k-1)] represents the value of the previous step, and Δv[x(k)] represents the nonlinear increment.

[0068] For the nonlinear controller with nonlinear increments represented by formula (6), two cases can be considered.

[0069] 1) If the dynamic changes of the unmodeled system are not very drastic, the nonlinear increment can be ignored. Therefore, the controller can be designed using formula (7), that is, the nonlinear controller without nonlinear increment can be expressed as:

[0070] A(z -1 )y(k+1)=B(z -1 )u(k)+v[x(k-1)] (7)

[0071] Among them, z -1 Denotes the delay operator, A(z) -1 B(z) represents the set of parameters for the output data added to the delay operator. -1 ) represents the set of parameters of the input data to be added to the delay operator, y(k+1) represents the output data of the next time step, k represents the kth time step, u(k) represents the input data, and v[x(k-1)] represents the value of the previous time step.

[0072] 2) If the dynamic changes of the unmodeled system are too drastic, the nonlinear increment cannot fully compensate for the loss of v[x(k-1)] and v[x(k)]. In this case, the square term of the nonlinear increment is used for compensation design. Therefore, the controller can be designed according to formula (1), that is, the nonlinear controller based on the square term of the nonlinear increment can be expressed as:

[0073] A(z -1 )y(k+1)=B(z -1 u(k) + v[x(k-1)] + Δv[x(k)] 2 (1)

[0074] Among them, z -1 Denotes the delay operator, A(z) -1 B(z) represents the set of parameters for the output data added to the delay operator. -1 Let represent the set of parameters of the input data with the delay operator added; y(k+1) represent the output data at the next time step, k represents the k-th time step, u(k) represent the input data, x(k) represent the data vector, v[x(k-1)] represents the higher-order smooth nonlinear function, and Δv[x(k)] represents the higher-order smooth nonlinear function. 2 This represents the squared term of the nonlinear increment.

[0075] Since the aforementioned designs of nonlinear controllers including nonlinear increments, nonlinear controllers without nonlinear increments, and nonlinear controllers based on the square term of nonlinear increments all use nonlinear increments Δv[x(k)], and Δv[x(k)] is unknown, a nonlinear increment estimation algorithm is used to estimate Δv[x(k)]. The parameter identification equation of the nonlinear increment estimation algorithm can be expressed by the following formula (8), i.e.

[0076]

[0077] in, Let represent the estimated value of Δv[x(k)], where Δv[x(k)] represents the nonlinear increment. This represents the estimated value of the output, a. i and b j Let x(k) represent the first-order coefficients at the origin, and x(k) represent the data vector, x(k) = [y(k), ..., y(k+1-n). s ),u(k),…,u(km s )] T v[x(k-1)] represents the value of v[x(k)] in the previous cycle, v[x(k)] represents a higher-order smooth nonlinear function, and n s and m s This indicates the order of a single-input, single-output nonlinear dynamic system.

[0078] The iterative identification of linear controllers will be introduced next.

[0079] In linear system control, an iterative identification method is used for system identification. The controller design steps based on the iterative identification method are as follows:

[0080] Step 1) For a given reduced-order power system model, online iterative identification processing is performed using noise-like signals of low-frequency oscillation modes of the power system. The least squares method is used to perform iterative closed-loop identification of the reduced-order model to determine the type of the given reduced-order power system model.

[0081] In this application, the reduced-order power system model G can be expressed by formula (9):

[0082]

[0083] Where z represents the variable parameters of the reduced-order model G.

[0084] Step 2) Determine the initial linear controller K based on the closed-loop stability condition of the power system; where the closed-loop stability condition is 1 + GK = 0; the initial linear controller is expressed by formula (10), i.e.

[0085]

[0086] Step 3) Calculate the Vinnicombe distance δ between data B1 obtained from the initial linear controller K and the preset data B2 based on the Vinnicombe distance. v (B1, B2). Here, the Vinnicombe distance represents the distance between two frequency responses, and can also be used as a measure of the distance between two transfer functions, denoted by the symbol δ. v The Vinnicombe distance between the two transfer functions G1 and G2 is expressed by formula (11), i.e.

[0087]

[0088] Where ω represents the frequency of the transfer function, j represents the imaginary part, and κ(G1(e iω ),G2(e iω )) represents the chord distance between the projection points of G1 and G2 onto the unit Riemann sphere, expressed by formula (12):

[0089]

[0090] Where ω represents the frequency of the transfer function, j represents the imaginary part, ω(G) represents the number of counterclockwise loops of the Nyquist curve around the point of the transfer function G, and the Nyquist curve avoids these poles when G has poles on the imaginary axis. η(G2) represents the number of poles in the open right half of the transfer function G2. This represents the number of poles in the closed right half of the transfer function G1.

[0091] κ(G1(e i ω),G2(e i ω)) is expressed by the following formula (13), that is

[0092]

[0093] Among them, G1 * (e jω ) = G2 * (e -jω ).

[0094] Step 4) Based on the calculated δ v (B1,B2), determine whether |δv(B1,B2)|≤0.05, that is, determine whether the error between the data obtained by the initial linear controller K and the preset data is less than 0.05.

[0095] Step 5) If the condition is met, the initial linear controller K is the optimal damped controller, i.e., the linear controller is iteratively identified, and K is used. op This indicates that if the conditions are not met, steps 2) through 4) are repeated to continue calculating the controller until the conditions are met. When the conditions are met, the controller is the optimal damped controller, i.e., the iteratively identified linear controller, using K... op This indicates that the system model obtained at this point is the optimal power system model, using G. op Indicates; where K op G can be expressed using formula (14). op Expressed using formula (15), that is:

[0096]

[0097]

[0098] Where z represents the variable parameter.

[0099] The method provided by this invention combines four types of controllers: iterative identification linear controller, nonlinear controller including nonlinear increment, nonlinear controller without nonlinear increment, and nonlinear controller based on the square term of nonlinear increment. This enables the data to be processed to be controlled within the target range, thereby improving the control effect of the data and thus enhancing the control performance of the power system.

[0100] Optionally, the specific implementation of step 102 above includes:

[0101] Based on the first identification result output by each controller, the distance between each first identification result and the preset identification result of each controller is calculated.

[0102] Specifically, based on the first identification results output by each controller, namely the first identification results output by the iteratively identified linear controller, the nonlinear controller including the nonlinear increment, the nonlinear controller excluding the nonlinear increment, and the nonlinear controller based on the square term of the nonlinear increment, the Vinnicombe distance between the first identification result corresponding to each controller and the preset identification result of the controller can be calculated using the above formula (10).

[0103] The method provided by this invention further judges the identification results of each controller by calculating the distance between the first identification result output by each controller and the preset identification result of each controller, laying the groundwork for subsequent switching control, thereby controlling the data to be processed within the target range, improving the control effect of the data, and thus improving the control performance of the power system.

[0104] Figure 2 This is a second schematic flowchart of the low-frequency oscillation control method provided by the present invention, as shown below. Figure 2 As shown, the method includes 201-204, wherein:

[0105] Step 201: Input the data to be processed into at least one controller to obtain the first identification result output by each controller; the data to be processed is generated by the low-frequency oscillation mode of the power system.

[0106] Step 202: Based on the first identification result output by each controller, determine the distance between each first identification result and the preset identification result of each controller.

[0107] Optionally, the explanations and descriptions of steps 201-202 can refer to the explanations and descriptions of steps 101-102 above, and the same technical effect can be achieved. To avoid repetition, they will not be repeated here.

[0108] Step 203: Compare the distance corresponding to each controller with the preset threshold corresponding to each controller, and determine the judgment result;

[0109] Step 204: Based on the judgment results corresponding to each controller, determine the target controller from each controller.

[0110] Specifically, the distance corresponding to each controller is compared with the preset threshold corresponding to each controller. It is determined whether the distance corresponding to each controller is less than the preset threshold corresponding to each controller, thereby determining whether each controller should terminate the identification calculation.

[0111] For example, the distance corresponding to the iterative identification linear controller is compared with the preset threshold of the iterative identification linear controller, where the preset threshold of the iterative identification linear controller is 0.01. If the distance corresponding to the iterative identification linear controller is less than 0.01, the iterative identification linear controller terminates the identification calculation; otherwise, the iterative identification linear controller continues to be used to identify and calculate the data to be processed until the distance corresponding to the iterative identification linear controller is less than 0.01.

[0112] The distance corresponding to the nonlinear controller including the nonlinear increment is compared with a preset threshold of 0.05 for the nonlinear controller including the nonlinear increment. If the distance corresponding to the nonlinear controller including the nonlinear increment is less than 0.05, the identification calculation for the nonlinear controller including the nonlinear increment is terminated; otherwise, the identification calculation for the data to be processed continues using the nonlinear controller including the nonlinear increment until the distance corresponding to the nonlinear controller including the nonlinear increment is less than 0.05. The preset thresholds for the nonlinear controller without the nonlinear increment and the nonlinear controller based on the square of the nonlinear increment are both 0.05, and their judgment process is the same as that for the nonlinear controller including the nonlinear increment. Therefore, to avoid repetition, this will not be described again.

[0113] The low-frequency oscillation control method provided by this invention determines the judgment result by comparing the distance corresponding to each controller with the preset threshold corresponding to each controller, and then determines the target controller from each controller based on the judgment result. This achieves the control of the data to be processed within the target range, improves the control effect of the data, and thus improves the control performance of the power system.

[0114] Optionally, step 204 above can be implemented by including the following steps:

[0115] Step 1) When the judgment result corresponding to each controller is less than the preset threshold, the first identification result output by each controller is input into the switching function for calculation to determine the performance index corresponding to each controller.

[0116] Step 2) Determine the target performance index based on the performance index corresponding to each controller;

[0117] Step 3) Based on the target performance index, determine the target controller from among the controllers.

[0118] Specifically, based on the iterative identification of the linear controller and three nonlinear incremental controllers described above, the system is switched using the following control strategy to form a closed-loop structure of the control system. The control strategy compares the distance between the first identification result output by each controller and the preset identification results of the four controllers. A target performance index is then introduced through a switching function to filter the four controllers, determine the target controller, and switch to it, thereby achieving system control by the target controller.

[0119] In this process, if the judgment results of each controller are all less than the preset threshold, the first identification result output by each controller is input into the switching function for calculation to determine the performance index of each controller.

[0120] Optionally, the switching function is expressed by formula (2):

[0121]

[0122] Where i represents the i-th controller, k represents the k-th time, and a i (l) represents the dead-zone function. Δ represents the boundary of the nonlinear increment Δv[x(k)], e i (l) represents the error value calculated using model i, w(l-1) represents the data vector at time l-1, c represents a constant, N is a positive integer, and l is a positive integer.

[0123] Specifically, This indicates the rate of increase of different signals in a controlled power system, thereby increasing the system's robustness.

[0124] In practice, the performance indicators of each controller are calculated based on the switching function, and J is used. i The following steps are taken: When i = 1, calculate the performance index J1 of the iterative identification linear controller; when i = 2, calculate the performance index J2 of the nonlinear controller including the nonlinear increment; when i = 3, calculate the performance index J3 of the nonlinear controller excluding the nonlinear increment; when i = 4, calculate the performance index J4 of the nonlinear controller based on the square term of the nonlinear increment.

[0125] Based on the calculated values ​​of performance indices J1, J2, J3, and J4, the performance index with the smallest value among these four performance indices is selected as the target performance index. The controller corresponding to this target performance index is the target controller. That is, the target controller is determined from the iteratively identified linear controller, nonlinear controller including nonlinear increment, nonlinear controller without nonlinear increment, and nonlinear controller based on the square term of nonlinear increment. The system is then switched to the target controller for control, thereby controlling the data within the target range.

[0126] It should be noted that the choice of constant c in the switching function has a certain impact on the smoothness of the switching performance. Therefore, in this embodiment, the constant c is selected in a step size of 10, and the range from 1 to 1000 is selected. The optimal constant c in this range is selected according to the input data, thereby achieving better control performance.

[0127] The low-frequency oscillation control method provided by this invention, after the judgment results of each controller are all less than a preset threshold, inputs the first identification result output by each controller into a switching function for calculation. The switching function determines the performance index corresponding to each controller. From the performance index corresponding to each controller, the performance index with the smallest value is determined as the target performance index. The controller corresponding to the target performance index is the target controller, and the system is switched to the target controller for control. This achieves the control of the data to be processed within the target range, improves the control effect of the data, and thus improves the control performance of the power system.

[0128] Figure 3 This is the third flowchart of the low-frequency oscillation control method provided by the present invention, as shown below. Figure 3 As shown, the method includes 301-316, wherein:

[0129] Step 301: For the given reduced-order power system model, online iterative identification processing is performed using noise-like signals of the low-frequency oscillation mode of the power system.

[0130] Step 302: Use the least squares method to perform iterative closed-loop identification on the reduced-order model to determine the type of the given reduced-order power system model;

[0131] Step 303: Determine the iteratively identified linear controller based on the iterative identification method;

[0132] Step 304: Input the data to be processed into the iterative identification linear controller to obtain the first identification result output by the iterative identification linear controller;

[0133] Step 305: Calculate the Vinnicombe distance between the first identification result and the preset identification result;

[0134] Step 306: Determine if the Vinnicombe distance is less than 0.01; if yes, proceed to step 314; if no, proceed to step 304.

[0135] Step 307: Use a nonlinear incremental estimation algorithm to identify the parameters of the unknown nonlinear increment Δv[x(k)].

[0136] Step 308: Based on the estimated nonlinear increment, design a nonlinear controller that includes the nonlinear increment, a nonlinear controller that does not include the nonlinear increment, and a nonlinear controller based on the square term of the nonlinear increment.

[0137] Step 309: Input the data to be processed into a nonlinear controller including nonlinear increment, a nonlinear controller without nonlinear increment, and a nonlinear controller based on the square term of nonlinear increment, respectively, and obtain the first identification results output by the nonlinear controller including nonlinear increment, the nonlinear controller without nonlinear increment, and the nonlinear controller based on the square term of nonlinear increment, respectively.

[0138] Step 310: Calculate the Vinnicombe distance between the first identification result, which includes the nonlinear increment of the nonlinear controller output, and the preset identification result;

[0139] Step 311: Calculate the Vinnicombe distance between the first identification result (excluding nonlinear increments) of the nonlinear controller output and the preset identification result;

[0140] Step 312: Calculate the Vinnicombe distance between the first identification result output by the nonlinear controller based on the squared term of the nonlinear increment and the preset identification result;

[0141] Step 313: Determine whether the calculated Vinnicombe distance for each controller is less than 0.05; if yes, proceed to step 314; if no, proceed to step 309.

[0142] Step 314: Input the first identification results of the iteratively identified linear controller, the nonlinear controller including nonlinear increment, the nonlinear controller without nonlinear increment, and the nonlinear controller based on the square term of nonlinear increment into the switching function for calculation to obtain the performance index corresponding to each controller.

[0143] Step 315: Determine the target performance indicators based on the performance indicators corresponding to each controller;

[0144] Step 316: Based on the target performance indicators, determine the target controller and switch to the target controller for system control.

[0145] It should be noted that in this embodiment of the application, IEEE PMU data and 10 machines and 39 nodes are used as basic data, and the voltage data of Sub1 and the first 1600 cycles of Ln1 are used as input data to be processed.

[0146] Figure 4 This is a schematic diagram of the switching control sequence provided by the present invention, as shown below. Figure 4 As shown, the control sequence represents the controllers that perform control in the system, starting from... Figure 4 As can be seen, during the time periods of 0s-200s, 200s-600s, and 600s-1200s, the first controller (iterative identification linear controller), the second controller (nonlinear controller including nonlinear increment), and the third controller (nonlinear controller excluding nonlinear increment) respectively provide control. At 1200s, the system switches to the fourth controller (nonlinear controller based on the square term of nonlinear increment) for control. That is, from 1200s to 1600s, the system is controlled by the nonlinear controller based on the square term of nonlinear increment, thus keeping the data within a stable range.

[0147] Figure 5 This is a schematic diagram showing the result of the low-frequency oscillation control method of the present invention, as shown below. Figure 5 As shown, taking voltage data as an example, within 0-50s, the voltage data input to the controller is in the range of 204.95V to 205.2V. By switching the four controllers through the switching function, the voltage data gradually tends to a stable state after 100s, and the voltage data stabilizes within a small target range.

[0148] The low-frequency oscillation control device provided by the present invention is described below. The low-frequency oscillation control device described below can be referred to in correspondence with the low-frequency oscillation control method described above.

[0149] Figure 6 This is a schematic diagram of the low-frequency oscillation control device provided by the present invention, as shown below. Figure 6 As shown, the low-frequency oscillation control device 600 includes: an identification module 601, a first determination module 602, and a second determination module 603; wherein:

[0150] The identification module 601 is used to input the data to be processed into at least one controller to obtain the first identification result output by each controller; the data to be processed is generated by the low-frequency oscillation mode of the power system.

[0151] The first determining module 602 is used to determine the distance between each first identification result and the preset identification result of each controller based on the first identification result output by each controller.

[0152] The second determining module 603 is used to determine a target controller from among the controllers based on the distances corresponding to each controller; the target controller is used to control the data to be processed within a target range.

[0153] The low-frequency oscillation control device provided by the present invention inputs the data to be processed into at least one controller and obtains the first identification result output by each controller; then, based on the first identification result output by each controller, the distance between each first identification result and the preset identification result of each controller is determined, and a target controller is determined from each controller. This achieves the control of the data to be processed within the target range, improves the control effect of the data, and thus improves the control performance of the power system.

[0154] Optionally, the second determining module 603 is specifically used for:

[0155] The distance corresponding to each controller is compared with the preset threshold corresponding to each controller to determine the judgment result;

[0156] Based on the judgment results corresponding to each controller, the target controller is determined from each controller.

[0157] Optionally, the second determining module 603 is specifically used for:

[0158] If the judgment result corresponding to each controller is less than the preset threshold, the first identification result output by each controller is input into the switching function for calculation to determine the performance index corresponding to each controller.

[0159] Based on the performance indicators corresponding to each controller, the target performance indicators are determined;

[0160] Based on the target performance indicators, a target controller is determined from among the controllers.

[0161] Optionally, the controller includes at least one of the following: an iterative identification linear controller, a nonlinear controller including nonlinear increments, a nonlinear controller not including nonlinear increments, and a nonlinear controller based on the square of the nonlinear increment; wherein the nonlinear controller based on the square of the nonlinear increment is represented by formula (1):

[0162] A(z -1 )y(k+1)=B(z -1 u(k) + v[x(k-1)] + Δv[x(k)] 2 (1)

[0163] Among them, z -1 Denotes the delay operator, A(z) -1B(z) represents the set of parameters for the output data added to the delay operator. -1 Let represent the set of parameters of the input data with the delay operator added; y(k+1) represent the output data at the next time step, k represents the k-th time step, u(k) represent the input data, x(k) represent the data vector, v[x(k-1)] represents the higher-order smooth nonlinear function, and Δv[x(k)] represents the higher-order smooth nonlinear function. 2 This represents the squared term of the nonlinear increment.

[0164] Optionally, the first determining module 602 is specifically used for:

[0165] Based on the first identification result output by each controller, the distance between each first identification result and the preset identification result of each controller is calculated.

[0166] Optionally, the switching function is expressed by formula (2):

[0167]

[0168] Where i represents the i-th controller, k represents the k-th time, and a i (l) represents the dead-zone function. Δ represents the boundary of the nonlinear increment Δv[x(k)], e i (l) represents the error value calculated using model i, w(l-1) represents the data vector at time l-1, c represents a constant, N is a positive integer, and l is a positive integer.

[0169] Figure 7 This is a schematic diagram of the physical structure of an electronic device provided by the present invention, such as... Figure 7 As shown, the electronic device 700 may include a processor 710, a communication interface 720, a memory 730, and a communication bus 740, wherein the processor 710, the communication interface 720, and the memory 730 communicate with each other through the communication bus 740. The processor 710 can call logic instructions in the memory 730 to execute a low-frequency oscillation control method, which includes: inputting data to be processed into at least one controller to obtain a first identification result output by each controller; the data to be processed is generated by a low-frequency oscillation mode of a power system; based on the first identification result output by each controller, determining the distance between each first identification result and a preset identification result of each controller; based on the distance corresponding to each controller, determining a target controller from among the controllers; the target controller is used to control the data to be processed within a target range.

[0170] Furthermore, the logical instructions in the aforementioned memory 730 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, essentially, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0171] On the other hand, the present invention also provides a computer program product, the computer program product including a computer program that can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer is able to execute the low-frequency oscillation control method provided by the above methods. The method includes: inputting data to be processed into at least one controller to obtain a first identification result output by each controller; the data to be processed is generated by a low-frequency oscillation mode of a power system; based on the first identification result output by each controller, determining the distance between each first identification result and a preset identification result of each controller; based on the distance corresponding to each controller, determining a target controller from among the controllers; the target controller is used to control the data to be processed within a target range.

[0172] In another aspect, the present invention also provides a non-transitory computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements a low-frequency oscillation control method provided by the above methods. The method includes: inputting data to be processed into at least one controller to obtain a first identification result output by each controller; the data to be processed being generated by a low-frequency oscillation mode of a power system; determining, based on the first identification result output by each controller, a distance between each first identification result and a preset identification result of each controller; determining a target controller from among the controllers based on the distances corresponding to each controller; the target controller being used to control the data to be processed within a target range.

[0173] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0174] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0175] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A low-frequency oscillation control method, characterized in that, The method includes: The data to be processed is input into an iterative identification linear controller, a nonlinear controller including nonlinear increments, a nonlinear controller without nonlinear increments, and a nonlinear controller based on the square of nonlinear increments, respectively. The iterative identification linear controller is used to calculate the data to be processed, and the first identification result output by the iterative identification linear controller is obtained. The nonlinear controller including nonlinear increments, the nonlinear controller without nonlinear increments, and the nonlinear controller based on the square of nonlinear increments are used to estimate the nonlinear increments of the data to be processed for parameter identification, and the first identification results output by the nonlinear controller including nonlinear increments, the nonlinear controller without nonlinear increments, and the nonlinear controller based on the square of nonlinear increments are obtained, respectively. The data to be processed is generated by a low-frequency oscillation mode of a power system. The controllers include: an iterative identification linear controller, a nonlinear controller including nonlinear increments, a nonlinear controller without nonlinear increments, and a nonlinear controller based on the square of nonlinear increments. Based on the first identification result output by each controller, the distance between each first identification result and the preset identification result of each controller is determined respectively; Based on the distances corresponding to each controller, a target controller is determined from each controller; the target controller is used to control the data to be processed within a target range.

2. The low-frequency oscillation control method according to claim 1, characterized in that, The step of determining the target controller from among the controllers based on the distances corresponding to each controller includes: The distance corresponding to each controller is compared with the preset threshold corresponding to each controller to determine the judgment result; Based on the judgment results corresponding to each controller, the target controller is determined from each controller.

3. The low-frequency oscillation control method according to claim 2, characterized in that, The step of determining the target controller from among the controllers based on the judgment results corresponding to each controller includes: If the judgment result corresponding to each controller is less than the preset threshold, the first identification result output by each controller is input into the switching function for calculation to determine the performance index corresponding to each controller. Based on the performance indicators corresponding to each controller, the target performance indicators are determined; Based on the target performance indicators, a target controller is determined from among the controllers.

4. The low-frequency oscillation control method according to any one of claims 1-3, characterized in that, The nonlinear controller based on the squared term of the nonlinear increment is expressed by formula (1): （1） in, Represents the delay operator, This represents the set of parameters for the output data added to the delay operator. This represents the set of parameters for the input data to be added to the delay operator; This represents the output data at the next time step, where k represents the k-th time step. Indicates input data, Represents a data vector. Represents a higher-order smooth nonlinear function. This represents the squared term of the nonlinear increment.

5. The low-frequency oscillation control method according to claim 1, characterized in that, The step of determining the distance between each first identification result and a preset identification result of each controller based on the first identification result output by each controller includes: Based on the first identification result output by each controller, the distance between each first identification result and the preset identification result of each controller is calculated.

6. The low-frequency oscillation control method according to claim 3, characterized in that, The switching function is expressed by formula (2): （2） Where i represents the i-th controller, and k represents the k-th time. Represents the dead-time function, , Represents nonlinear increment The boundary, This represents the error value calculated using the i-model. express The data vector at time step, where c represents a constant and N is a positive integer. l It is a positive integer.

7. A low-frequency oscillation control device, characterized in that, The device includes: An identification module is used to input the data to be processed into an iterative identification linear controller, a nonlinear controller including nonlinear increments, a nonlinear controller without nonlinear increments, and a nonlinear controller based on the square of nonlinear increments, respectively. The iterative identification linear controller is used to calculate the data to be processed, obtaining a first identification result output by the iterative identification linear controller. The nonlinear controllers including nonlinear increments, nonlinear controllers without nonlinear increments, and nonlinear controllers based on the square of nonlinear increments are used to perform parameter identification on the data to be processed by estimating the relevant nonlinear increments, respectively, obtaining the first identification results output by the nonlinear controllers including nonlinear increments, nonlinear controllers without nonlinear increments, and nonlinear controllers based on the square of nonlinear increments, respectively. The data to be processed is generated by a low-frequency oscillation mode of a power system. The controllers include: an iterative identification linear controller, a nonlinear controller including nonlinear increments, a nonlinear controller without nonlinear increments, and a nonlinear controller based on the square of nonlinear increments. The first determining module is used to determine the distance between each first identification result and the preset identification result of each controller based on the first identification result output by each controller. The second determining module is used to determine a target controller from among the controllers based on the distances corresponding to each controller; the target controller is used to control the data to be processed within a target range.

8. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the low-frequency oscillation control method as described in any one of claims 1 to 6.

9. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the low-frequency oscillation control method as described in any one of claims 1 to 6.

10. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by the processor, it implements the low-frequency oscillation control method as described in any one of claims 1 to 6.

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