Transient stability control method and system for equilibrium point continuation of power system after disturbance

Abstract

The invention discloses a transient stability control method and system for a power system with equilibrium point continuation after disturbance, and the method comprises the steps: firstly building a steady-state mathematical expression of each dynamic element, and constructing a solving model of a system equilibrium point in combination with a power network equation; then, a homotopy method is introduced, homotopy parameter values at saddle node bifurcation points are solved, and whether balance points still exist in the system or not is judged; and for the condition of system instability, further deriving the sensitivity of the fault parameter of the homotopy curve at the saddle node bifurcation point to each control variable, and optimizing the adjustment strategy of the adjustable parameter in combination with the sensitivity and the control cost. Through a systematic search method, the optimal control scheme with the lowest cost is determined on the premise that the stability margin is met, and therefore the economical efficiency and effectiveness of control measures are improved. The optimization adjustment direction of each adjustable parameter can be accurately identified, the effectiveness of a control scheme is ensured, and accurate operation is provided for stability recovery of a power system.

Description

Background Art

[0002] Accurately analyzing the operating equilibrium point of the system after being disturbed and giving an analytical control basis is crucial for identifying the reasons for instability and formulating effective control strategies.

[0003] Currently, the methods for obtaining the equilibrium point of the power system mainly rely on time-domain simulation and power flow calculation. Although time-domain simulation can relatively accurately reflect the dynamic characteristics of the system, its computational complexity is huge, making it difficult to meet the requirements of rapid stability assessment; while the power flow calculation method, although having high computational efficiency, is difficult to accurately depict the dynamic behavior of the system, resulting in its limitations in instability analysis. In addition, traditional control strategies usually adopt the method of adjusting the generator output in groups for stability control, but such methods are difficult to accurately evaluate the control effect without analytical guidance.

[0004] Therefore, it is urgent to develop more efficient equilibrium point calculation methods and explore accurate control strategies based on analytical theory guidance to improve the security and stability of the power system. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a transient stability control method and system for a power system with extended equilibrium points after being disturbed, aiming at the deficiencies in the above-mentioned prior art. By establishing an equilibrium point solution model of the system after being disturbed under the network structure retention model, the differential equation of the system is avoided to solve, which is used to solve the technical problems of large matrix dimension and slow calculation speed. Through the gradient information at the saddle-node bifurcation point, an analytical basis for formulating control strategies is given, realizing the efficient and accurate control of the power system.

[0006] The present invention adopts the following technical solutions: A transient stability control method for a power system with extended equilibrium points after being disturbed, comprising the following steps: S1. Conduct a power flow calculation on the power system before being disturbed to obtain the initial steady-state parameters, which are used as the iteration initial values and evaluate the initial operating characteristics of the power system; based on the power system topology, construct a steady-state analysis model and introduce a dynamic element model, and derive the steady-state mathematical expression of the power system; S2. Based on the steady-state mathematical expression of the power system derived in step S1, parameterize the fault parameters of the power system according to different fault types; use the homotopy method to iteratively solve the saddle-node bifurcation point, analyze the equilibrium state of the power system under different fault parameters, and judge whether the system still has a stable equilibrium point after the fault occurs; S3. For the situation where the power system loses its equilibrium point under a specific fault, calculate the sensitivity of the fault parameters to the control variables at the saddle-node bifurcation point, identify the variables that have the most significant impact on stability; based on the sensitivity analysis results, optimize the control variable adjustment strategy to make the fault parameters exceed the set critical value to ensure the system returns to stability.

[0007] Preferably, when deriving the steady-state mathematical expression of the power system, the actual operating frequency of the system after being disturbed is used to construct a solution model for the equilibrium point of the entire system after being disturbed.

[0008] Preferably, the solution model for the equilibrium point of the entire system after being disturbed is as follows:

[0009] where, represents all unknown state variables; represents adjustable control parameters, which respectively correspond to adjusting the opening to adjust the output of the synchronous generator set, adjusting the excitation voltage to adjust the terminal voltage of the generator, adjusting the load size, and adjusting the active power output of the wind farm.

[0010] Preferably, the homotopy method is used for iterative solution of the saddle-node bifurcation point, analyzing the equilibrium state of the power system under different fault parameters, and judging whether the system still has a stable equilibrium point after the fault occurs. Specifically: After the system is disturbed, the homotopy method is used for iterative solution. By introducing the homotopy parameter , the evolution process of the power system is traced respectively under the conditions of removing the line after three-phase short circuit, output change and load change; when , the power system is in the steady state before the disturbance occurs; when , it corresponds to the state of the power system after being disturbed; through the homotopy method solution, is gradually increased until , at this time, a saddle-node bifurcation point appears in the power system after being disturbed. Suppose there is a solution at the saddle-node bifurcation point. Keeping the control parameters unchanged, that is, , the saddle-node bifurcation point of the system after being disturbed before taking control measures is solved . If , a balance point manifold is found at , indicating that there is still a stable equilibrium point in the system after being disturbed; no equilibrium point is found at , and the power system after being disturbed has become unstable.

[0011] Preferably, after removing the line after three-phase short circuit, the admittance matrix after the disturbance occurs is:

[0012] where, is the admittance matrix of the power system before being disturbed, is the homotopy parameter, is the change amount of the admittance matrix of the power system after being disturbed; Output change, the generator output at node a changes from to , then we have:

[0013] where, is the value of the generator output at node a during the disturbance process, is the initial value of the generator output at node a before the disturbance, is the final value of the generator output at node a after the disturbance; Load change, the load at node b changes from to , then we have:

[0014] where, is the value of the load at node b during the disturbance process, is the initial value of the load at node b before the disturbance, is the final value of the load at node b after the disturbance.

[0015] Preferably, solve the post-disturbance system saddle-node bifurcation point before taking control measures, specifically as follows:

[0016] where, is the parameterized full-system equilibrium point solving model, are the system variables at the saddle-node bifurcation point, is the corresponding homotopy parameter value at the saddle-node bifurcation point, are adjustable parameters.

[0017] Preferably, for the case where the post-disturbance power system loses its equilibrium point under a specific fault, adjust the key operating parameters to change the stability boundary of the system; specifically as follows: Adjust the saddle-node bifurcation point in the unstable state to a new saddle-node bifurcation point , to restore the equilibrium state of the system; use to approximate the stability margin of the system, calculate the homotopy parameter at the saddle-node bifurcation point, calculate the sensitivity of the adjustable operating parameter , and conduct a sorting analysis on the sensitivity values of each parameter to increase the parameter , decrease the parameter , and increase to achieve the effect of improving the system stability margin; when adjusting the adjustable parameters to construct a new equilibrium point, select multiple high-sensitivity parameters for coordinated adjustment.

[0018] Preferably, when adjusting the adjustable parameters to construct a new equilibrium point, when the homotopy parameter corresponding to the adjusted saddle-node bifurcation point reaches the set value the homotopy curve and the straight line reappear the intersection point, indicating that there is a stable equilibrium point in the adjusted system; transform the corresponding problem into an optimization problem of solving the minimum control cost; solve the optimization problem of the minimum control cost:

[0019] wherein, and are control parameters the upper and lower bounds of the adjustable range; is the number of control parameters, is the change amount of the homotopy parameter, is the set target value of the homotopy parameter, is the adjustment amount of the adjustable parameter.

[0020] Preferably, the measures of generator tripping and load shedding meet the following conditions:

[0021] wherein, is a control parameter, is the opening of the water turbine / steam turbine, is the active power load, is the active power output of the wind turbine.

[0022] In a second aspect, an embodiment of the present invention provides a transient stability control system for a power system with the continuation of the equilibrium point after disturbance, including: A derivation module that performs power flow calculation on the power system before disturbance, obtains the initial steady-state parameters as the initial values of iteration and evaluates the initial operating characteristics of the power system; constructs a steady-state analysis model based on the power system topology and introduces a dynamic element model to derive the steady-state mathematical expression of the power system; An iteration module that, based on the derived steady-state mathematical expression of the power system, parameterizes the fault parameters of the power system according to different fault types; uses the homotopy method to iteratively solve the saddle-node bifurcation point, analyzes the equilibrium state of the power system under different fault parameters, and determines whether the system still has a stable equilibrium point after the fault occurs; A control module that, for the situation where the power system loses the equilibrium point under a specific fault, calculates the sensitivity of the fault parameters to the control variables at the saddle-node bifurcation point, and identifies the variable that has the most significant impact on stability; based on the sensitivity analysis results, optimizes the control variable adjustment strategy to make the fault parameters exceed the set critical value to ensure the system returns to stability.

[0023] In a third aspect, a computer device includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of the power system transient stability control method for extending the post-disturbance equilibrium point are implemented.

[0024] In a fourth aspect, an embodiment of the present invention provides a computer-readable storage medium including a computer program. When the computer program is executed by a processor, the steps of the power system transient stability control method for extending the post-disturbance equilibrium point are implemented.

[0025] In a fifth aspect, a chip includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of the power system transient stability control method for extending the post-disturbance equilibrium point are implemented.

[0026] In a sixth aspect, an embodiment of the present invention provides an electronic device including a computer program. When the computer program is executed by the electronic device, the steps of the power system transient stability control method for extending the post-disturbance equilibrium point are implemented.

[0027] Compared with the prior art, the present invention has at least the following beneficial effects: A power system transient stability control method for extending the post-disturbance equilibrium point directly solves the algebraic equation under the steady state of the system, avoiding the solution of complex differential equations, saving a large amount of time and computing resources. By using the homotopy method for iterative solution, the convergence is better and the requirement for the initial value is lower. Compared with the traditional method of adjusting the generator output after system grouping, this method can provide an analytical guiding basis for instability control. This analytical characteristic not only helps to deeply understand the system instability mechanism, but also can provide a quantitative theoretical basis for the formulation of control strategies, thus improving the scientificity and reliability of the control scheme.

[0028] Furthermore, a solution model for the post-disturbance equilibrium point of the system considering the dynamic characteristics of components is established, and the actual operating frequency of the post-disturbed system is used as the new reference frequency, so that the reference frame rotates synchronously with the system, eliminating the false dynamics caused by the asynchronous coordinate system and accurately reflecting the stability of the relative power angle.

[0029] Furthermore, by parameterizing the disturbance, the state tracking of the post-disturbed system is realized, which is convenient for quantitatively analyzing the influence of the disturbance on the system and accurately determining the existence of the post-disturbance equilibrium point of the system.

[0030] Furthermore, through sensitivity analysis, the adjustment direction and adjustment amplitude of each control variable are quantified, and the system saddle-node bifurcation point is pulled to the safety threshold through collaborative optimization adjustment, realizing precise and efficient stability control.

[0031] It can be understood that the beneficial effects of the above second aspect to the sixth aspect can be referred to the relevant descriptions in the above first aspect, and will not be repeated here.

[0032] In summary, the present invention greatly improves the calculation efficiency of the system equilibrium point after being disturbed, provides an analytical control basis for emergency control in the case of instability, and optimizes the automatic generation efficiency and accuracy of the control strategy.

[0033] The technical solution of the present invention will be further described in detail below with reference to the drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required to be used in the embodiments of the present application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application, and those of ordinary skill in the art can also obtain other drawings based on these drawings without creative efforts.

[0035] Figure 1 It is a homotopy curve graph before and after measures are taken for the system after being disturbed; Figure 2 It is a flowchart of the present invention; FIG. 3 is a time-domain simulation graph and a homotopy curve graph after the New England 10-machine system is disturbed; Figure 4 It is a time-domain simulation graph after control measures are taken for the New England 10-machine system; Figure 5 It is a geographical connection diagram of the provincial power system; FIG. 6 is a time-domain simulation graph and a homotopy curve graph after the provincial power system is disturbed; Figure 7 It is a time-domain simulation graph after control measures are taken for the provincial power system; Figure 8 It is a schematic diagram of a computer device provided by an embodiment of the present invention; Figure 9 It is a block diagram of an electronic device provided by an embodiment of the present invention.

[0036] Among them, 60. Computer device; 61. Processor; 62. Memory; 63. Computer program; 600. Electronic device; 610. Processing unit; 620. Storage unit; 6201. Random access storage unit; 6202. Cache storage unit; 6203. Read-only storage unit; 6204. Program / utilities; 6205. Program module; 630. Bus; 640. Display unit; 650. Input / output interface; 660. Network adapter; 700. External device. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0037] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part rather than all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0038] In the description of the present invention, it should be understood that the terms "including" and "comprising" indicate the presence of the described features, wholes, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or their combinations.

[0039] It should also be understood that the terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the specification of the present invention and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include the plural forms.

[0040] It should be further understood that the term " / and" as used in the specification of the present invention and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations. For example, A and / or B can represent three cases: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in the present invention generally represents an "or" relationship between the contextually related objects.

[0041] It should be understood that although the terms first, second, third, etc. may be used in the embodiments of the present invention to describe preset ranges, etc., these preset ranges should not be limited to these terms. These terms are only used to distinguish the preset ranges from each other. For example, without departing from the scope of the embodiments of the present invention, the first preset range may also be referred to as the second preset range, and similarly, the second preset range may also be referred to as the first preset range.

[0042] Depending on the context, the word "if" as used herein can be interpreted as "when" or "while" or "in response to determining" or "in response to detecting". Similarly, depending on the context, the phrase "if determined" or "if detecting (stated condition or event)" can be interpreted as "when determined" or "in response to determining" or "when detecting (stated condition or event)" or "in response to detecting (stated condition or event)".

[0043] Various structural schematic diagrams according to the disclosed embodiments of the present invention are shown in the accompanying drawings. These figures are not drawn to scale, where for the purpose of clear expression, some details are enlarged and some details may be omitted. The shapes of various regions and layers shown in the figures, as well as their relative sizes and positional relationships, are merely exemplary and may deviate in practice due to manufacturing tolerances or technical limitations. Those skilled in the art can additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0044] The present invention provides a transient stability control method for power systems with extended post-disturbance equilibrium points to accurately analyze the dynamic response of the system after disturbances and provide efficient control decision support. This method first establishes the steady-state mathematical expressions of each dynamic component and constructs a solution model for the system equilibrium point in combination with the power network equations. Subsequently, the homotopy method is introduced to solve the homotopy parameter values at the saddle-node bifurcation point to determine whether the system still has an equilibrium point. For the case of system instability, this method further derives the sensitivities of the homotopy curve to each control variable at the saddle-node bifurcation point with respect to the fault parameters, and optimizes the adjustment strategy of the adjustable parameters by combining the sensitivities and control costs. Through a systematic search method, the optimal control scheme with the lowest cost is determined under the premise of meeting the stability margin, thereby improving the economy and effectiveness of control measures. This study not only provides an efficient calculation tool for the dynamic behavior of the system after being disturbed, but also provides a theoretical basis for instability control based on the analytical analysis method. This strategy can accurately identify the optimal adjustment directions of each adjustable parameter and ensure the effectiveness of the control scheme, providing a precise and operable technical means for the stability restoration of power systems.

[0045] Embodiment 1 Please refer to Figure 2 , a transient stability control method for power systems with extended post-disturbance equilibrium points according to the present invention, includes the following steps: S1. Perform power flow calculations on the pre-disturbed system to obtain the initial steady-state parameters, which are used as the iterative initial values for subsequent analysis and evaluate the initial operating characteristics of the system; construct a steady-state analysis model based on the power system topology, covering power sources, loads, and transmission networks, and introduce dynamic component models to derive the steady-state mathematical expressions of the system to accurately describe its operating characteristics; Construct a system equilibrium point solution model to ensure that the dynamic behavior of the system under steady-state conditions is accurately described. In terms of power source modeling, the present invention selects synchronous generator sets as the research object and uses a sixth-order model to describe their dynamic characteristics. The prime mover takes the most common water turbine as an example, the excitation selects a thyristor rectifier excitation system, the load is described by the ZIP model, and the equations at the grid connection point are considered. This model can comprehensively depict the electromagnetic, mechanical, and excitation system dynamic responses of synchronous generators, thus more accurately reflecting the operating state of the system after being disturbed.

[0046] Specifically, when establishing the steady-state equation, the traditional power frequency is no longer used , but instead, it is replaced with the actual operating frequency of the system after being disturbed to make the description more in line with the actual physical process. Through this method, a model for solving the equilibrium point of the entire system after being disturbed is constructed and abbreviated as follows: (1) Wherein, , , respectively represent the numbers corresponding to synchronous generator sets, wind turbine generator sets, and loads; and are the vectors composed of the output currents of all generators and the vectors composed of all load currents; is the system admittance matrix; is the vector composed of all node voltages; is the system frequency; is the angular position of the generator rotor at node ; and respectively represent the terminal voltage and output current of the generator at node ; and represent the voltage reference value and opening reference value of the generator at node ; , , and are the voltage, current, and wind power of the wind turbine generator set at node , , respectively represent the voltage, current, and active load of the load at node .

[0047] Equation (1) is abbreviated as: (2) Wherein, represents all the unknown state variables in Equation (1); represents the adjustable control parameters. The four quantities in the brackets respectively correspond to adjusting the opening to adjust the output of the synchronous generator set, adjusting the excitation voltage to adjust the terminal voltage of the generator, adjusting the load size, and adjusting the active power output of the wind farm.

[0048] S2. According to different fault types, parameterize the key parameters of the system, such as short-circuit faults, output changes, load changes, etc.; use the homotopy method for iterative solution of the saddle-node bifurcation point, analyze the equilibrium state of the system under different fault parameters, and judge whether the system still has a stable equilibrium point after the fault occurs; When the system is disturbed, in order to describe the continuous change of the disturbance, the homotopy method is used for iterative solution. This method introduces a homotopy parameter to track the evolution process of the system under different disturbance states and ensure the smooth transition of the system from the initial state to the new steady state.

[0049] The following takes the line removal, output change, and load change after a three-phase short circuit as examples to introduce the modification idea of the model, and other faults can be inferred by analogy.

[0050] (1)Line removal after a three-phase short circuit Taking the example that a tie line between nodes and is removed after a three-phase short circuit, use and to represent the shunt admittance to ground and the impedance admittance matrix of the line respectively. Then the corresponding elements in , , and change as follows: (3) Thus, we have: (4) Among them, represents the admittance matrix after the disturbance occurs.

[0051] Introduce the parameter to describe the correlation between the systems before and after the disturbance, and thus describe the admittance matrix as: (5) (2)Output change Suppose the output of the generator at node a changes from to , then we have: (6) (3)Load change Suppose the load at node b changes from to , then we have: (7) When the above-mentioned faults occur in the system, incorporate the corresponding equations in equations (5), (6), and (7) into equation (2) and abbreviate it as: (8) Among them, the homotopy parameter has a clear physical meaning: when , the system is in the steady state before the disturbance occurs; and when At this time, it corresponds to the perturbed system state. Solved by the homotopy method, gradually increase until , at this time, a saddle-node bifurcation point appears in the system.

[0052] Assume that there is a solution at the saddle-node bifurcation point in Equation (8), and keep the control parameter unchanged, that is , then the saddle-node bifurcation point of the perturbed system before taking control measures can be solved according to Equation (8) , satisfying: (9) If , that is, if a balance point manifold can be found at , it indicates that there is still a stable equilibrium point in the perturbed system, as shown by the green line in Figure 1 .

[0053] Conversely, if no equilibrium point can be found at , it means that the system has become unstable, as shown by the black line in Figure 1 .

[0054] S3. For the situation where the system loses the equilibrium point under specific faults, calculate the sensitivity of the fault parameters to the control variables at the saddle-node bifurcation point, and identify the variables that have the most significant impact on stability; based on the analysis results, optimize the adjustment strategy of the key control variables to make the fault parameters exceed the set critical value, ensuring that the system recovers stability and improves the overall stability.

[0055] For an unstable system, the stability boundary of the system can be changed by adjusting the key operating parameters (such as the active power output of the generator, etc.). Specifically, the saddle-node bifurcation point in the unstable state can be adjusted to a new saddle-node bifurcation point , as shown by the arrow in Figure 1 , so as to restore the equilibrium state of the system. Use to approximate the stability margin of the system, the larger it is, the better the system stability.

[0056] At the saddle-node bifurcation point , the Jacobian matrix is singular and satisfies: (10) Therefore, there must be a left eigenvector corresponding to the zero eigenvalue, such that: (11) Expand Equation (8) according to the first-order Taylor expansion and ignore other terms except the first term, we get: (12) Thus, multiply both sides of Equation (20) by to obtain The gradient information of the control parameter vector is: (13) where the -th element of is the sensitivity to the -th adjustable parameter .

[0057] Calculate the sensitivity of the homotopy parameter at the saddle-node bifurcation point according to Equation (13), and sort and analyze the sensitivity values of each parameter, as shown in Equation (24).

[0058] (14) Based on this, increase the parameter , decrease the parameter , so as to increase to achieve the effect of improving the system stability margin.

[0059] Since when the system is close to the saddle-node bifurcation point, the sensitivity change trend is linearly distributed, the deviation between its calculated value and the actual value is small, thus ensuring the accuracy of the sensitivity analysis. When adjusting the adjustable parameters to construct a new equilibrium point, a large adjustment of a single parameter may lead to the instability of the system operation. Therefore, a more reasonable strategy is to select multiple high-sensitivity parameters for collaborative adjustment to improve the control effect and enhance the stability of the system.

[0060] When the homotopy parameter corresponding to the adjusted saddle-node bifurcation point reaches the set value , the homotopy curve and the straight line reappear at the intersection point, indicating that there is a stable equilibrium point in the adjusted system. Considering that the adjustment cost needs to be reduced during the adjustment process, that is, the degree of deviation of the adjusted parameter from the original parameter should be minimized as much as possible, then this problem can be transformed into an optimization problem of solving the minimum control cost: (15) where and are the upper and lower bounds of the adjustable range of the control parameter ; is the number of control parameters.

[0061] For the measures of generator tripping and load shedding, considering the system power balance, it is necessary to satisfy: (16) Those skilled in the art can understand that various aspects of the present invention can be implemented as a system, a method, or a program product. Therefore, various aspects of the present invention can be specifically implemented in the following forms, namely: a complete hardware implementation, a complete software implementation (including firmware, microcode, etc.), or an implementation combining hardware and software aspects, which can be collectively referred to as "circuit", "module", or "platform".

[0062] Embodiment 2 The present invention provides a transient stability control system for a power system with extended post-disturbance equilibrium points, which can be used to implement the transient stability control method for the power system with extended post-disturbance equilibrium points. Specifically, the transient stability control system for the power system with extended post-disturbance equilibrium points includes a derivation module, an iteration module, and a control module.

[0063] Among them, the derivation module performs a power flow calculation on the pre-disturbance power system to obtain initial steady-state parameters, which are used as the initial values for iteration and to evaluate the initial operating characteristics of the power system; based on the power system topology, a steady-state analysis model is constructed and a dynamic element model is introduced to derive the steady-state mathematical expression of the power system; The iteration module, based on the derived steady-state mathematical expression of the power system, parameterizes the fault parameters of the power system according to different fault types; uses the homotopy method to iteratively solve the saddle-node bifurcation point, analyzes the equilibrium state of the power system under different fault parameters, and determines whether the system still has a stable equilibrium point after the fault occurs; The control module, for the situation where the power system loses the equilibrium point under a specific fault, calculates the sensitivity of the fault parameters to the control variables at the saddle-node bifurcation point, and identifies the variables that have the most significant impact on stability; based on the sensitivity analysis results, optimizes the control variable adjustment strategy to make the fault parameters exceed the set critical value to ensure the system returns to stability.

[0064] Embodiment 3 The present invention provides a terminal device, which includes a processor and a memory. The memory is used to store a computer program, and the computer program includes program instructions. The processor is used to execute the program instructions stored in the computer storage medium. The processor may be a Central Processing Unit (CPU), or may also be other general-purpose processors, Graphics Processing Unit (GPU), Tensor Processing Unit (TPU), Digital Signal Processor (DSP), Application Specific Integrated Circuit (ASIC), Field-Programmable Gate Array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. It is the computing core and control core of the terminal, and is suitable for implementing one or more instructions, specifically suitable for loading and executing one or more instructions to implement the corresponding method flow or corresponding function; The processor described in the embodiment of the present invention can be used for the operation of the transient stability control method of the power system with the continuation of the post-disturbance equilibrium point, including: Perform a power flow calculation on the power system before the disturbance, obtain the initial steady-state parameters, use them as the initial values for iteration and evaluate the initial operating characteristics of the power system; construct a steady-state analysis model based on the power system topology and introduce a dynamic element model to derive the steady-state mathematical expression of the power system; based on the derived steady-state mathematical expression of the power system, parameterize the fault parameters of the power system according to different fault types; use the homotopy method to iteratively solve the saddle-node bifurcation point, analyze the equilibrium state of the power system under different fault parameters, and determine whether the system still has a stable equilibrium point after the fault occurs; for the situation where the power system loses the equilibrium point under a specific fault, calculate the sensitivity of the fault parameters at the saddle-node bifurcation point to the control variables, and identify the variables that have the most significant impact on stability; based on the sensitivity analysis results, optimize the control variable adjustment strategy to make the fault parameters exceed the set critical value to ensure the system returns to stability.

[0065] Please refer to Figure 8, the terminal device is a computer device. The computer device 60 in this embodiment includes: a processor 61, a memory 62, and a computer program 63 stored in the memory 62 and executable on the processor 61. When the computer program 63 is executed by the processor 61, it implements the power system transient stability control method for the post-disturbance equilibrium point extension in the embodiment. To avoid repetition, it will not be elaborated here one by one. Alternatively, when the computer program 63 is executed by the processor 61, it implements the functions of each model / unit in the power system transient stability control system for the post-disturbance equilibrium point extension in the embodiment. To avoid repetition, it will not be elaborated here one by one.

[0066] The computer device 60 can be a computing device such as a desktop computer, a notebook, a handheld computer, and a cloud server. The computer device 60 may include, but is not limited to, a processor 61 and a memory 62. Those skilled in the art can understand that Figure 8 merely examples of the computer device 60, which do not constitute a limitation on the computer device 60, may include more or fewer components than those shown in the figure, or combine certain components, or different components. For example, the computer device may also include input / output devices, network access devices, buses, etc.

[0067] The so-called processor 61 may be a central processing unit (CPU), or may also be other general-purpose processors, a graphics processing unit (GPU), a tensor processing unit (TPU), a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc.

[0068] The memory 62 may be an internal storage unit of the computer device 60, such as the hard disk or memory of the computer device 60. The memory 62 may also be an external storage device of the computer device 60, such as a plug-in hard disk equipped on the computer device 60, a smart media card (SMC), a secure digital (SD) card, a flash card, etc.

[0069] Further, the memory 62 may also include both internal storage units of the computer device 60 and external storage devices. The memory 62 is used to store computer programs and other programs and data required by the computer device. The memory 62 may also be used to temporarily store data that has been output or is to be output.

[0070] Please refer to Figure 9 , the terminal device is the electronic device 600, and the electronic device 600 is presented in the form of a general computing device. The components of the electronic device may include but are not limited to: at least one processing unit 610, at least one storage unit 620, a bus 630 connecting different platform components (including the storage unit 620 and the processing unit 610), a display unit 640, etc.

[0071] Among them, the storage unit stores program codes, and the program codes can be executed by the processing unit 610, so that the processing unit 610 executes the steps according to various exemplary embodiments of the present invention described in the above method part of this specification. For example, the processing unit 610 can execute steps as shown in Figure 2 .

[0072] The storage unit 620 may include a readable medium in the form of a volatile storage unit, such as a random access storage unit (RAM) 6201 and / or a cache storage unit 6202, and may further include a read-only storage unit (ROM) 6203.

[0073] The storage unit 620 may also include a program / utilities 6204 having a set (at least one) of program modules 6205. Such program modules 6205 include but are not limited to: an operating system, one or more application programs, other program modules, and program data. The implementation of the network environment may be included in each or some combination of these examples.

[0074] The bus 630 may represent one or more of several types of bus structures, including a memory bus or a memory controller, a peripheral bus, a graphics acceleration port, a processing unit, or a local bus using any of the multiple bus structures.

[0075] The electronic device 600 can also communicate with one or more external devices 700 (such as a keyboard, a pointing device, a Bluetooth device, etc.), and can also communicate with one or more devices that enable a user to interact with the electronic device 600, and / or communicate with any device that enables the electronic device 600 to communicate with one or more other computing devices (such as a router, a modem). Such communication can be carried out through the input / output interface 650. Moreover, the electronic device 600 can also communicate with one or more networks (such as a local area network, a wide area network, and / or a public network, such as the Internet) through the network adapter 660. The network adapter 660 can communicate with other modules of the electronic device 600 through the bus 630. It should be understood that although not shown in the figure, other hardware and / or software modules can be used in combination with the electronic device 600, including but not limited to: microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, and data backup storage platforms, etc.

[0076] Embodiment 4 The present invention also provides a storage medium, specifically a computer-readable storage medium, which is a memory device in a terminal device for storing programs and data. It can be understood that the computer-readable storage medium here can include both the built-in storage medium in the terminal device and, of course, the extended storage medium supported by the terminal device. It can be any tangible medium that contains or stores a program, and this program can be used by or in combination with an instruction execution system, apparatus, or device. The computer-readable storage medium provides a storage space that stores the operating system of the terminal. And, in this storage space, one or more instructions suitable for being loaded and executed by the processor are also stored. These instructions can be one or more computer programs (including program codes). It should be noted that more specific examples of the computer-readable storage medium here include: an electrical connection having one or more wires, a portable disk, a hard disk, a random access memory, a read-only memory, an erasable programmable read-only memory, an optical fiber, a portable compact disk read-only memory, an optical storage device, a magnetic storage device, or any suitable combination of the above.

[0077] The computer-readable storage medium also includes a data signal propagated in a baseband or as part of a carrier wave, which carries the readable program code. Such a propagated data signal can take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. The readable storage medium can also be any readable medium other than the readable storage medium, which can send, propagate, or transmit a program for use by or in conjunction with an instruction execution system, apparatus, or device. The program code contained on the readable storage medium can be transmitted using any appropriate medium, including but not limited to wireless, wired, optical fiber cable, radio frequency, etc., or any suitable combination of the above.

[0078] The program code for performing the operations of the present invention can be written in any combination of one or more programming languages. The programming languages include object-oriented programming languages such as Java, C++, etc., and also include conventional procedural programming languages such as the "C" language or similar programming languages. The program code can be executed entirely on the user's computing device, partially on the user's device, executed as an independent software package, partially on the user's computing device and partially on a remote computing device, or entirely on a remote computing device or server. In the case of a remote computing device, the remote computing device can be connected to the user's computing device through any type of network, including a local area network or a wide area network, or can be connected to an external computing device (e.g., by using an Internet service provider to connect through the Internet).

[0079] One or more instructions stored in the computer-readable storage medium can be loaded and executed by a processor to implement the corresponding steps of the power system transient stability control method for the post-disturbance equilibrium point extension in the above embodiments; one or more instructions in the computer-readable storage medium are loaded and executed by the processor as follows: Perform a power flow calculation on the pre-disturbed power system to obtain the initial steady-state parameters, which are used as the initial values for iteration and to evaluate the initial operating characteristics of the power system; construct a steady-state analysis model based on the power system topology and introduce a dynamic element model to derive the steady-state mathematical expression of the power system; based on the derived steady-state mathematical expression of the power system, parameterize the fault parameters of the power system according to different fault types; use the homotopy method to iteratively solve the saddle-node bifurcation point, analyze the equilibrium states of the power system under different fault parameters, and determine whether the system still has a stable equilibrium point after the fault occurs; for the case where the power system loses its equilibrium point under a specific fault, calculate the sensitivity of the fault parameters at the saddle-node bifurcation point to the control variables to identify the variables that have the most significant impact on stability; based on the sensitivity analysis results, optimize the control variable adjustment strategy to make the fault parameters exceed the set critical value to ensure the system returns to stability.

[0080] In each of the embodiments provided in this application, the database involved may include at least one of a relational database and a non-relational database. The non-relational database may include a distributed database based on blockchain, etc., and is not limited thereto. In each of the embodiments provided in this application, the processor involved may be a general-purpose processor, a central processing unit, a graphics processing unit, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., and is not limited thereto.

[0081] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Usually, the components described and shown in the accompanying drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed present invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0082] To verify the correctness and practicability of the transient stability control strategy for power systems based on the extension of the post-disturbance equilibrium point proposed in the present invention, tests were conducted on the New England 10-machine 39-bus system and an actual provincial power system.

[0083] 1) New England 10-machine system The initial frequency of the system is 50 Hz. Consider the following disturbance conditions.

[0084] Table 1 Description of disturbance information for the New England 10-machine system

[0085] According to the present invention, the operating conditions of the system after being disturbed are analyzed and compared with the simulation results of DSP 2.3.39.2. The final results are shown in the following table: Table 2 Comparison of the calculation results of the present invention with the simulation results of existing simulation software

[0086] As can be seen from Table 2, the error between the final results of the present invention and the existing simulation software is very small, and the required time and computing resources are significantly reduced. For the 3rd disturbance, the time-domain simulation results and homotopy diagrams after the disturbance are shown in Figure 3.

[0087] After the disturbance occurs, the relative power angles between the generator groups G1 and G8, G2 and G10, and G3, G4, G5, G6, G7, and G9 continuously increase, and the system is in an oscillatory out-of-step state. Correspondingly, , indicating that the main reason is that there is no equilibrium point in the system after being disturbed.

[0088] Taking the adjustment of the active power output of the generator as an example, the sensitivity to the active power can be calculated according to Equation (22) and is shown in Table 3 below. (The meaning of the sensitivity here is: for every 100 MW change in the generator output, the change amount at the saddle-node bifurcation point) Table 3 Sensitivity of the homotopy parameter at the saddle-node bifurcation point to the generator output

[0089]

[0090] Set , and formulate the control strategy according to Equations (25) and (26) as follows: (1) Increase the outputs of generators G8 and G1 by 50 MW and 45.73 MW respectively; (2) Decrease the outputs of generators G3 and G5 by 50 MW and 45.73 MW respectively.

[0091] Take control measures 0.2 s after the three-phase short-circuit fault line is removed. The homotopy curve is at the saddle-node bifurcation point , indicating that there is an equilibrium point in the system. The relative power angles of all the network generators gradually converge to the steady-state value after experiencing small fluctuations, and the system finally returns to stability. The time-domain simulation results (as Figure 4 shown) further verify this conclusion. It should be noted that compared with the traditional method that roughly adjusts depending on the overall power angle change of the generator group, the control strategy proposed in this paper is based on analytical analysis, can accurately identify the regulation direction of the key parameters of the system, thereby ensuring the effectiveness and pertinence of the control measures, and significantly improving the reliability of the system stability recovery.

[0092] 2) Actual provincial power system The geographical connection diagram is as Figure 5 shown. The initial frequency of the system is 50 Hz, and the following disturbance conditions are considered.

[0093] Table 4 Description of the disturbance information of the actual provincial power system

[0094] Analyze the operating conditions of the system after being disturbed according to the present invention, and compare with the simulation results of DSP 2.3.39.2. The final results are shown in the following table: ​Table 5 Comparison between the calculation results of the present invention and the simulation results of existing simulation software

[0095] As can be seen from Table 5, the present invention can still effectively improve the calculation efficiency and ensure good accuracy in large-scale power systems. For the 3rd disturbance, the time-domain simulation results and homotopy diagrams after the disturbance are shown in Figure 6.

[0096] After the disturbance occurs, generally speaking, significant out-of-step oscillations occur between the generators on the left side (green frame) and the generators on the right side (blue frame) of the system. According to the calculation in Equation (23), the sensitivities to the active power are shown in Table 6 below.

[0097] Table 6 Sensitivities of homotopy parameters at the saddle-node bifurcation point to the generator output of

[0098]

[0099] Set , and formulate the control strategy according to Equations (25) and (26) as follows: (1) Increase the output powers of the , and generators by 200 MW, 200 MW, and 193.64 MW respectively; (2) Decrease the output powers of the , and generators by 200 MW, 200 MW, and 193.64 MW respectively.

[0100] Take control measures 0.2 s after the three-phase short-circuit fault line is removed. The homotopy curve is at the saddle-node bifurcation point , indicating that there is an equilibrium point in the system. The relative power angles of all network generators gradually converge to the steady-state value after experiencing small fluctuations, and the system finally returns to stability. The time-domain simulation results (as Figure 7 shown) further verify this conclusion.

[0101] In summary, a transient stability control method and system for a power system with extended equilibrium points after disturbance of the present invention realizes the efficient calculation of the equilibrium point of the power system after disturbance and the accurate and rapid generation of the emergency control strategy of the power system under unstable conditions.

[0102] Those skilled in the art can clearly understand that, for the convenience and brevity of description, only the above-mentioned division of each functional unit and module is used as an example. In actual applications, the above functions can be allocated to different functional units and modules according to needs, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. Each functional unit and module in the embodiment can be integrated into a processing unit, or each unit can exist physically alone, or two or more units can be integrated into one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of a software functional unit. In addition, the specific names of each functional unit and module are only for the convenience of mutual distinction and do not limit the protection scope of this application. The specific working processes of the units and modules in the above system can refer to the corresponding processes in the foregoing method embodiments and will not be elaborated herein.

[0103] In the above embodiments, the descriptions of the various embodiments have their own emphases. For the parts not detailed or recorded in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0104] Those of ordinary skill in the art can realize that the units and algorithm steps of each example described in combination with the embodiments disclosed in the present invention can be implemented by electronic hardware, or by a combination of computer software and electronic hardware. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. A professional technician can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present invention.

[0105] In the embodiments provided by the present invention, it should be understood that the disclosed device / terminal and method can be implemented in other ways. For example, the device / terminal embodiments described above are merely illustrative. For example, the division of the modules or units is only a logical function division. In actual implementation, there can be other division methods. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed couplings or direct couplings or communication connections to each other can be through some interfaces. The indirect couplings or communication connections of the devices or units can be in an electrical, mechanical or other forms.

[0106] The units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they can be located in one place or distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0107] In addition, in each embodiment of the present invention, each functional unit can be integrated into one processing unit, or each unit can exist physically alone, or two or more units can be integrated into one unit. The above integrated unit can be implemented in the form of hardware or in the form of a software functional unit.

[0108] If the integrated module / unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on such an understanding, to implement all or part of the processes in the above-described embodiment methods of the present invention, it can also be completed by a computer program instructing relevant hardware. The computer program can be stored in a computer-readable storage medium. When the computer program is executed by a processor, the steps of the above-described method embodiments can be implemented. Among them, the computer program includes computer program code, and the computer program code can be in the form of source code, object code, an executable file, or some intermediate form, etc. The computer-readable medium can include: any entity or device capable of carrying the computer program code, a recording medium, a USB flash drive, a mobile hard disk, a magnetic disk, an optical disk, a computer memory, a read-only memory (ROM), a random access memory (RAM), an electrical carrier signal, a telecommunication signal, and a software distribution medium, etc. It should be noted that the content included in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, the computer-readable medium does not include electrical carrier signals and telecommunication signals.

[0109] This application is described with reference to the flowcharts and / or block diagrams of methods, apparatuses, and computer program products according to embodiments of the present application. It should be understood that each process and / or block in the flowchart and / or block diagram can be implemented by computer program instructions, and the combination of processes and / or blocks in the flowchart and / or block diagram can also be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate a device for implementing the functions specified in Figure 1 one process or multiple processes and / or blocks Figure 1 one block or multiple blocks.

[0110] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory generate a manufactured product including an instruction device, and the instruction device implements the processes in Figure 1One or more processes and / or boxes Figure 1 The functions specified in one or more boxes.

[0111] These computer program instructions can also be loaded onto a computer or other programmable data processing device, so that a series of operation steps are executed on the computer or other programmable device to generate a computer-implemented process. Thus, the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in one Figure 1 One or more processes and / or boxes Figure 1 The steps of the functions specified in one or more boxes.

[0112] The above content is only to illustrate the technical idea of the present invention, and the protection scope of the present invention cannot be limited thereby. Any modification made on the basis of the technical solution according to the technical idea proposed by the present invention falls within the protection scope of the claims of the present invention.

Claims

1. A transient stability control method for a power system with the extension of the post-disturbance equilibrium point, characterized in that, It includes the following steps: S1. Conduct a power flow calculation on the power system before being disturbed to obtain the initial steady-state parameters, which are used as the initial values for iteration and to evaluate the initial operating characteristics of the power system; construct a steady-state analysis model based on the power system topology and introduce a dynamic element model to derive the steady-state mathematical expression of the power system; S2. Based on the steady-state mathematical expression of the power system derived in step S1, parameterize the fault parameters of the power system according to different fault types; use the homotopy method to iteratively solve the saddle-node bifurcation point, analyze the equilibrium states of the power system under different fault parameters, and determine whether the system still has a stable equilibrium point after the fault occurs; S3. For the situation where the power system loses its equilibrium point under a specific fault, calculate the sensitivity of the fault parameters at the saddle-node bifurcation point to the control variables, and identify the variables that have the most significant impact on stability; Based on the sensitivity analysis results, optimize the control variable adjustment strategy to make the fault parameters exceed the set critical value and ensure the system returns to stability.

2. The transient stability control method for a power system with extended post-disturbance equilibrium point according to claim 1, characterized in that When deriving the steady-state mathematical expression of the power system, the actual operating frequency of the system after being disturbed is used to construct a solution model for the equilibrium point of the entire system after being disturbed.

3. The transient stability control method for a power system with extended post-disturbance equilibrium points according to claim 2, characterized in that, The equilibrium point solution model for the entire system after being disturbed is: Among them, represents all unknown state variables; represents adjustable control parameters, corresponding to adjusting the opening to adjust the output of the synchronous generator set, adjusting the excitation voltage to adjust the generator terminal voltage, adjusting the load size, and adjusting the active power output of the wind farm, respectively.

4. The transient stability control method for a power system with extended post-disturbance equilibrium points according to claim 1, characterized in that Use the homotopy method to iteratively solve the saddle-node bifurcation point, analyze the equilibrium states of the power system under different fault parameters, and determine whether the system still has a stable equilibrium point after the fault occurs. Specifically: After the system is perturbed, the homotopy method is used for iterative solution. By introducing the homotopy parameter , the evolution process of the power system is traced respectively under the conditions of line removal, output change, and load change after three-phase short circuit; when , the power system is in a steady state before the perturbation occurs; when , it corresponds to the state of the power system after being perturbed; through the solution by the homotopy method, is gradually increased until , at this time, a saddle-node bifurcation point appears in the power system after being perturbed. Suppose there is a solution at the saddle-node bifurcation point. Keeping the control parameters unchanged, that is , the saddle-node bifurcation point of the perturbed system before taking control measures is solved . If , a stable equilibrium manifold is found at , indicating that there is still a stable equilibrium point in the perturbed system; no equilibrium point is found at , and the power system after being perturbed has become unstable.

5. The transient stability control method for a power system with extended post-disturbance equilibrium point according to claim 4, characterized in that, After the three-phase short circuit, the line is disconnected, and the admittance matrix after the disturbance occurs is as follows: Among them, is the admittance matrix of the power system before being disturbed, is the homotopy parameter, is the change amount of the admittance matrix of the power system after being disturbed; Output change, the generator output at node a changes from to , then there is: Among them, is the value of the generator output at node a during the disturbance process, is the initial value of the generator output at node a before the disturbance, is the final value of the generator output at node a after the disturbance; When the load changes and the load at node b changes from to , then we have: Among them, is the value of the load at node b during the disturbance process, is the initial value of the load at node b before the disturbance, is the final value of the load at node b after the disturbance.

6. The transient stability control method for a power system with extended post-disturbance equilibrium point according to claim 4, characterized in that, Solve for the saddle-node bifurcation point of the perturbed system before taking control measures , as follows: Among them, is the solution model of the full-system equilibrium point after parameterization, are the variables of the system at the saddle-node bifurcation point, is the corresponding homotopy parameter value at the saddle-node bifurcation point, are adjustable parameters.

7. The transient stability control method for a power system with extended post-disturbance equilibrium points according to claim 1, characterized in that For the situation where the power system after being disturbed loses its equilibrium point under a specific fault, adjust the key operating parameters to change the stability boundary of the system. Specifically as follows: Adjust the saddle-node bifurcation point in the unstable state to a new saddle-node bifurcation point , and restore the equilibrium state of the system; use to approximate the stability margin of the system and calculate the homotopy parameter at the saddle-node bifurcation point for the adjustable operating parameters sensitivity, and sort and analyze the sensitivity values of each parameter to improve the parameter , reduce the parameter , and improve to achieve the effect of improving the system stability margin; when adjusting the adjustable parameters to construct a new equilibrium point, select multiple high-sensitivity parameters for collaborative adjustment.

8. The transient stability control method for a power system with extended post-disturbance equilibrium point according to claim 7, characterized in that, When adjusting the adjustable parameters to construct a new equilibrium point, when the homotopy parameter corresponding to the adjusted saddle-node bifurcation point reaches the set value the homotopy curve and the straight line re-appear an intersection point, indicating that there is a stable equilibrium point in the adjusted system; transform the corresponding problem into an optimization problem of solving the minimum control cost; solve the optimization problem of the minimum control cost: Among them, and are the upper and lower bounds of the adjustable range of the control parameter ; is the number of control parameters, is the change amount of the homotopy parameter, is the set target value of the homotopy parameter, is the adjustment amount of the adjustable parameter.

9. The transient stability control method for a power system with extended post-disturbance equilibrium point according to claim 7, characterized in that The conditions satisfied by the generator tripping and load shedding measures are as follows: Among them, is a control parameter, is the opening of the water turbine / steam turbine, is the active power load, is the active power output of the wind turbine generator set.

10. A transient stability control system for a power system with extended equilibrium points after disturbance, characterized in that, It includes: A derivation module that conducts a power flow calculation on the power system before being disturbed to obtain the initial steady-state parameters, which are used as the initial values for iteration and to evaluate the initial operating characteristics of the power system; Construct a steady-state analysis model based on the power system topology and introduce a dynamic element model to derive the steady-state mathematical expression of the power system; An iteration module that, based on the derived steady-state mathematical expression of the power system, parameterizes the fault parameters of the power system according to different fault types; Use the homotopy method to iteratively solve the saddle-node bifurcation point, analyze the equilibrium states of the power system under different fault parameters, and determine whether the system still has a stable equilibrium point after the fault occurs; A control module that, for the situation where the power system loses its equilibrium point under a specific fault, calculates the sensitivity of the fault parameters at the saddle-node bifurcation point to the control variables, and identifies the variables that have the most significant impact on stability; Based on the sensitivity analysis results, optimize the control variable adjustment strategy to make the fault parameters exceed the set critical value and ensure the system returns to stability.

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