Transient power angle stability evaluation index calculation method, system and device based on point-by-point grouping and storage medium

Abstract

The invention discloses a transient power angle stability evaluation index calculation method, system and device based on point-by-point grouping, and a storage medium. The method comprises the steps of obtaining a phase angle and a frequency of a synchronous generator at each simulation time point in a transient process after preset disturbance in a preset power grid operation state; calculating an inertia center phase angle and an inertia center frequency of the power grid at each simulation time point; for each simulation time point, grouping the synchronous generators at each simulation time point according to whether the phase angle of the synchronous generator is greater than the inertia center phase angle of the power grid; determining a transient power angle stability evaluation index calculation period and a stability mark; calculating a transient power angle stability evaluation index of each time period; and determining a final transient power angle stability evaluation index and a stability mark after preset disturbance in a preset power grid operation state. According to the method, the possible difference of the influence of each time point of the synchronous generator on the power angle stability in the transient process is fully considered, and a basis is provided for quantitative evaluation of the transient power angle stability of the power system after different operation states and different disturbances.

Description

Technical Field

[0001] This invention belongs to the field of transient stability analysis of power systems, and specifically relates to a method, system, equipment and storage medium for calculating transient power angle stability evaluation index based on point-by-point grouping. Background Technology

[0002] The Transient Stability Assessment Index (TSAI) is a key indicator for evaluating a power system's ability to maintain synchronous operation after a large disturbance. Existing calculation methods fall into two categories: time-domain simulation-based methods and energy function methods. Time-domain simulation-based methods are further divided into those based on multiple simulations and those based on a single simulation. The multiple simulation-based method determines the power system operating state corresponding to the critical stability of the transient power angle after a large disturbance through repeated simulations, using the distance between this state and the initial state to characterize the TSAI in the initial state. This method involves a large computational load. The single simulation-based method extracts margin information from a single simulation result. For example, the extended equal-area method groups synchronous generators based on their phase angle trajectories, and the TSAI is determined based on the equivalence between the two groups. However, this method does not fully consider the potential differences in the impact of synchronous generators on power angle stability at different points in time during the transient process. The energy function method refers to constructing a transient energy function based on Lyapunov stability theory. It quantizes the margin by the difference between potential energy and kinetic energy. It does not require time-domain simulation and has a fast calculation speed. However, this method is usually based on simplified models (such as classical second-order models) and is difficult to handle complex models of real-world systems. Summary of the Invention

[0003] Purpose of the invention: The purpose of this invention is to provide a method, system, device and storage medium for calculating transient power angle stability evaluation index based on point-by-point grouping, which fully considers the possible differences in the impact of synchronous generators on power angle stability at different points in time during the transient process.

[0004] Technical solution: The present invention provides a method for calculating transient power angle stability evaluation index based on point-by-point grouping, comprising:

[0005] The inertia, phase angle, and frequency of the synchronous generator at each simulation time point are obtained based on time-domain simulation during the transient process after a preset disturbance under the preset power grid operating state.

[0006] Based on the inertia, phase angle, and frequency of the synchronous generator at each simulation time point, calculate the inertia center phase angle and inertia center frequency of the power grid at each simulation time point.

[0007] For each simulation time point, the synchronous generators at each simulation time point are grouped according to whether the phase angle of the synchronous generator is greater than the phase angle of the inertia center of the power grid.

[0008] Based on the phase angle difference of the inertia center between synchronous generator groups and the maximum phase angle difference of synchronous generators at each simulation time point, the calculation period and stability indicator of transient power angle stability evaluation index are determined.

[0009] Based on the transient power angle stability assessment index, the power grid inertia center frequency and synchronous generator frequency and inertia at each simulation time point within the time period are calculated, and the transient power angle stability assessment index for each time period is calculated.

[0010] Based on the transient power angle stability assessment index and stability indicator for each time period, the final transient power angle stability assessment index and stability indicator after the preset disturbance under the preset power grid operating state are determined.

[0011] Furthermore, the calculation formulas for the inertia center phase angle and inertia center frequency of the power grid at each simulation time point are as follows:

[0012]

[0013] In the formula, θ i ω i These represent the phase angle and frequency of the power grid's inertia center at the i-th simulation time point, respectively; G i M represents the complete set of synchronous generators in the power grid at the i-th simulation time point; i.g θ i.g ω i.g Let be the inertia, phase angle, and frequency of the synchronous generator g at the i-th simulation time point, respectively.

[0014] Furthermore, for each simulation time point, the synchronous generators at each simulation time point are grouped according to whether their phase angle is greater than the phase angle of the grid's inertia center, including:

[0015] The complete set G of synchronous generators in the power grid at the i-th simulation time point i The phase angle of the synchronous generator is greater than the phase angle θ of the grid inertia center. i The set of all synchronous generators is called the phase-leading synchronous generator set G at the i-th simulation time point. i.u ,Will The phase lag synchronous generator set G at the i-th simulation time point i.d .

[0016] Furthermore, based on the phase angle difference of the inertia centers among the synchronous generator groups and the maximum phase angle difference of the synchronous generators at each simulation time point, the calculation period and stability indicators for the transient power angle stability assessment index are determined, including:

[0017] The phase angle difference θ between the inertia centers of the synchronous generator group at the i-th simulation time point is calculated using the following formula. i.ud The phase angle difference of the inertia center between the synchronous generator groups at each simulation time point was obtained;

[0018]

[0019] Among them, G i.u M represents the leading synchronous generator set at the i-th simulation time point; i.g θ i.g These represent the inertia and phase angle of the synchronous generator g at the i-th simulation time point; G i.d For the phase-lag synchronous generator set at the i-th simulation time point;

[0020] The simulation point at which the phase angle difference between the inertia centers of the synchronous generator groups reaches its extreme value in each simulation time point is taken as the critical simulation time point.

[0021] The simulation point at which the maximum phase angle difference of the synchronous generator first exceeds the set value for transient power angle instability judgment in each simulation point is taken as the critical simulation point;

[0022] The number of key simulation time points is used as the number of calculation periods for the transient power angle stability evaluation index. Based on the timing of the key simulation time points during the transient process, the period between the first simulation time point and the first key simulation time point during the transient process is used as the calculation period for the first transient power angle stability evaluation index. The period between the first key simulation time point and the second key simulation time point is used as the calculation period for the second transient power angle stability evaluation index, and so on. The period between the second-to-last key simulation time point and the last key simulation time point is used as the calculation period for the last transient power angle stability evaluation index.

[0023] If the maximum phase angle difference of the synchronous generator at each simulation point in the calculation period of the transient power angle stability evaluation index is not greater than the transient power angle instability judgment setting value, then the stability flag for that period is set to stable; otherwise, the stability flag for that period is set to unstable.

[0024] Furthermore, the calculation formulas for the transient power angle stability evaluation index for each time period are as follows:

[0025]

[0026] In the formula, x i η represents the kinetic energy deviation rate of all synchronous generators in the power grid relative to the center frequency of inertia at the i-th simulation time point; j For the calculation of the transient power angle stability assessment index, I is the transient power angle stability assessment index corresponding to the j-th transient power angle stability assessment index; j.s I j.e These represent the start and end times of the simulation time corresponding to the calculation period of the j-th transient power angle stability evaluation index; Δt i ω represents the duration between the i-th simulation time point and the (i+1)-th simulation time point; up ω dnThese are the upper and lower limits of the set transient frequency safety values; G i.u G represents the leading synchronous generator set at the i-th simulation time point; i.d For the phase lag synchronous generator set at the i-th simulation time point; ω i ω is the center frequency of the power grid's inertia at the i-th simulation time point; i.g M is the frequency of the synchronous generator g at the i-th simulation time point; i.g Let g be the inertia of the synchronous generator g at the i-th simulation time point.

[0027] Furthermore, based on the transient power angle stability assessment indicators and stability indicators for each time period, the final transient power angle stability assessment indicators and stability indicators after the preset disturbance under the preset grid operating state are determined, including:

[0028] If the transient power angle stability flag is stable in all time periods, the maximum value is extracted from the evaluation index of all time periods and used as the final transient power angle stability evaluation index after the preset disturbance under the preset power grid operating state, and the final stability flag is set to stable; otherwise, the evaluation index of the time period with the transient power angle stability flag as unstable is used as the final transient power angle stability evaluation index after the preset disturbance under the preset power grid operating state, and the final stability flag is set to unstable.

[0029] Furthermore, the synchronous generator includes conventional synchronous generators and virtual synchronous generators.

[0030] Based on the same inventive concept, the present invention provides a transient power angle stability evaluation index calculation system based on point-by-point grouping, comprising:

[0031] The time-domain simulation module is used to obtain the inertia, phase angle, and frequency of the synchronous generator at each simulation time point in the transient process after a preset disturbance under the preset power grid operating state based on time-domain simulation.

[0032] The inertia center phase angle and frequency calculation module is used to calculate the inertia center phase angle and inertia center frequency of the power grid at each simulation time point based on the inertia, phase angle and frequency of the synchronous generator at each simulation time point.

[0033] The synchronous generator grouping module is used to group synchronous generators at each simulation time point based on whether the phase angle of the synchronous generator is greater than the phase angle of the inertia center of the power grid.

[0034] The calculation period and stability indicator determination module is used to determine the calculation period and stability indicator of transient power angle stability evaluation index based on the phase angle difference of the inertia center between synchronous generator groups and the maximum phase angle difference of synchronous generators at each simulation time point.

[0035] The time period evaluation index calculation module is used to calculate the power grid inertia center frequency and synchronous generator frequency and inertia at each simulation time point within the time period based on the transient power angle stability evaluation index, and to calculate the transient power angle stability evaluation index for each time period.

[0036] The final evaluation index and stability indicator determination module is used to determine the final transient power angle stability evaluation index and stability indicator after a preset disturbance under the preset power grid operating state, based on the transient power angle stability evaluation index and stability indicator for each time period.

[0037] Based on the same inventive concept, the present invention provides a transient power angle stability evaluation index calculation device based on point-by-point grouping, comprising a processor and a memory. The memory stores computer instructions, and the processor executes the computer instructions stored in the memory. When the computer instructions are executed by the processor, the device implements the steps of the above-described transient power angle stability evaluation index calculation method based on point-by-point grouping.

[0038] Based on the same inventive concept, the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the above-described method for calculating transient power angle stability evaluation index based on point-by-point grouping.

[0039] Beneficial effects: Compared with the prior art, the significant technical effects of the present invention are as follows: (1) Based on the phase angle and frequency trajectory of the synchronous generator obtained by a detailed model time-domain simulation, the transient power angle stability evaluation index is calculated. Compared with the multiple time-domain simulation method, the calculation speed is faster, and compared with the energy function method, the power grid model has stronger adaptability; (2) By comparing the relative relationship between the phase angle of the synchronous generator and the phase angle of the power grid inertia center at each simulation time point after the disturbance, the synchronous generator is dynamically grouped point by point, so as to realize the qualitative judgment of the influence of the synchronous generator on the transient power angle stability at each simulation time point; (3) Based on the accumulation of the kinetic energy deviation of the synchronous generator relative to the power grid inertia center frequency during the transient process, the transient power angle stability evaluation index of the power system is constructed, which is in line with the essential requirement of each synchronous generator in the power grid to maintain frequency synchronization operation, and provides a basis for the quantitative evaluation of the transient power angle stability of the power system under different operating conditions and different disturbances. Attached Figure Description

[0040] Figure 1 This is a flowchart illustrating a method for calculating transient power angle stability evaluation index based on point-by-point grouping, as disclosed in an embodiment of the present invention.

[0041] Figure 2 This is a schematic diagram of the structure of a transient power angle stability evaluation index calculation system based on point-by-point grouping disclosed in an embodiment of the present invention;

[0042] Figure 3This is a schematic diagram of the structure of a transient power angle stability evaluation index calculation device based on point-by-point grouping disclosed in an embodiment of the present invention. Detailed Implementation

[0043] The technical solution of the present invention will now be described in detail with reference to specific embodiments and accompanying drawings.

[0044] Example 1

[0045] Please see Figure 1 , Figure 1 This is a flowchart illustrating a method for calculating transient power angle stability evaluation indices based on point-by-point grouping, as disclosed in an embodiment of the present invention. Figure 1 The described method for calculating transient power angle stability evaluation indices is applicable to power systems, such as for power system transient stability analysis, etc., and the embodiments of this invention are not limited thereto. Figure 1 As shown, the method for calculating the transient power angle stability evaluation index based on point-by-point grouping can include the following operations:

[0046] S1. Based on time-domain simulation, obtain the inertia, phase angle and frequency of the synchronous generator at each simulation time point during the transient process after the preset disturbance under the preset power grid operating state.

[0047] Among them, synchronous generators include conventional synchronous generators and virtual synchronous generators. During transient processes, the inertia of a conventional synchronous generator remains constant, while the inertia of a virtual synchronous generator changes and is related to its control model parameters.

[0048] S2. Calculate the inertia center phase angle and inertia center frequency of the power grid at each simulation time point based on the inertia, phase angle and frequency of the synchronous generator at each simulation time point.

[0049] In this embodiment, the formulas for calculating the inertia center phase angle and inertia center frequency of the power grid at each simulation time point are as follows:

[0050]

[0051] In the formula, θ i ω i These represent the phase angle and frequency of the power grid's inertia center at the i-th simulation time point, respectively; G i M represents the complete set of synchronous generators in the power grid at the i-th simulation time point; i.g θ i.g ω i.g Let be the inertia, phase angle, and frequency of the synchronous generator g at the i-th simulation time point, respectively.

[0052] S3. For each simulation time point, the synchronous generators at each simulation time point are grouped according to whether their phase angle is greater than the phase angle of the grid's inertia center. The details are as follows:

[0053] For the i-th simulation time point, the complete set G of synchronous generators in the power grid at the i-th simulation time point is... i The phase angle of the synchronous generator is greater than the phase angle θ of the grid inertia center. i The set of all synchronous generators is called the phase-leading synchronous generator set G at the i-th simulation time point. i.u ,Will The phase lag synchronous generator set G at the i-th simulation time point i.d .

[0054] S4. Based on the phase angle difference of the inertia center between synchronous generator groups and the maximum phase angle difference of synchronous generators at each simulation time point, determine the calculation period and stability indicator of the transient power angle stability evaluation index.

[0055] The specific implementation process of step S4 is as follows:

[0056] S4.1 Calculate the phase angle difference θ between the inertia centers of the synchronous generator group at the i-th simulation time point using the following formula. i.ud The phase angle difference of the inertia center between the synchronous generator groups at each simulation time point was obtained.

[0057]

[0058] S4.2. The simulation point at which the phase angle difference between the inertia centers of the synchronous generator groups reaches its extreme value in each simulation time point is taken as the key simulation time point.

[0059] It should be noted that if the duration between adjacent extreme points in the phase angle difference time series data of the inertia center between synchronous generator groups is less than the set value (usually 40ms), then such extreme points will be removed from the key simulation time points.

[0060] S4.3. The simulation point at which the maximum phase angle difference of the synchronous generator first exceeds the transient power angle instability judgment setting value (usually set to 360°) in each simulation time point is taken as the key simulation time point.

[0061] S4.4. The number of key simulation time points is used as the number of calculation periods for the transient power angle stability evaluation index. Based on the timing of the key simulation time points during the transient process, the time period between the first simulation time point and the first key simulation time point during the transient process is used as the calculation period for the first transient power angle stability evaluation index. The time period between the first key simulation time point and the second key simulation time point is used as the calculation period for the second transient power angle stability evaluation index. And so on, the time period between the second-to-last key simulation time point and the last key simulation time point is used as the calculation period for the last transient power angle stability evaluation index.

[0062] S4.5 If the maximum phase angle difference of the synchronous generator at each simulation time point during the calculation period of the transient power angle stability evaluation index is not greater than the transient power angle instability judgment setting value, then the stability flag for that period is set to stable; otherwise, the stability flag for that period is set to unstable.

[0063] S5. Calculate the center frequency of the power grid inertia and the frequency and inertia of the synchronous generator at each simulation point in time period based on the transient power angle stability evaluation index, and calculate the transient power angle stability evaluation index for each time period.

[0064] In this embodiment, the calculation formulas for the transient power angle stability evaluation index at each time period are as follows:

[0065]

[0066] In the formula, x i η represents the kinetic energy deviation rate of all synchronous generators in the power grid relative to the center frequency of inertia at the i-th simulation time point; j For the calculation of the transient power angle stability assessment index, I is the transient power angle stability assessment index corresponding to the j-th transient power angle stability assessment index; j.s I j.e These represent the start and end times of the simulation time corresponding to the calculation period of the j-th transient power angle stability evaluation index; Δt i ω represents the duration between the i-th simulation time point and the (i+1)-th simulation time point; up ω dn These are the upper and lower limits of the set transient frequency safety, which are usually set to 1.01 times and 0.99 times the rated frequency, respectively, based on the generator's allowable frequency fluctuation range.

[0067] S6. Based on the transient power angle stability assessment index and stability indicator for each time period, determine the final transient power angle stability assessment index and stability indicator after the preset disturbance under the preset power grid operating state.

[0068] If the transient power angle stability flag is stable in all time periods, the maximum value is extracted from the evaluation index of all time periods and used as the final transient power angle stability evaluation index after the preset disturbance under the preset power grid operating state, and the final stability flag is set to stable; otherwise, the evaluation index of the time period with the transient power angle stability flag as unstable is used as the final transient power angle stability evaluation index after the preset disturbance under the preset power grid operating state, and the final stability flag is set to unstable.

[0069] It should be noted that, for cases where the final stability is indicated by stability, the smaller the transient power angle stability evaluation index, the higher the degree of transient power angle stability; for cases where the final stability is indicated by instability, the smaller the transient power angle stability evaluation index, the more severe the degree of transient power angle instability.

[0070] This invention considers the differences in the impact of synchronous generators on power angle stability at different points in time during transient processes. Based on the phase angle of the grid inertia center at each point in time, the synchronous generators are dynamically grouped point by point. Based on the kinetic energy difference of the synchronous generators relative to the grid inertia center frequency at each point in time, the transient power angle stability evaluation index of the power system after disturbance is calculated.

[0071] The above method enables the calculation of transient power angle stability evaluation index of power system based on a single time-domain simulation, providing a basis for rapid comparison of the degree of transient power angle stability of power system under different operating states and different disturbances. It can be used to guide power system planning, operation mode arrangement and control decision optimization.

[0072] Example 2

[0073] Please see Figure 2 , Figure 2 This is a schematic diagram of a transient power angle stability evaluation index calculation system based on point-by-point grouping disclosed in an embodiment of the present invention. This system can realize transient stability analysis of power systems, specifically including:

[0074] The time-domain simulation module is used to obtain the phase angle and frequency of synchronous generators at each simulation time point in the transient process after a preset disturbance under a preset power grid operating state based on time-domain simulation.

[0075] The inertia center phase angle and frequency calculation module is used to calculate the inertia center phase angle and inertia center frequency of the power grid at each simulation time point based on the inertia, phase angle and frequency of the synchronous generator at each simulation time point.

[0076] The synchronous generator grouping module is used to group synchronous generators at each simulation time point based on whether the phase angle of the synchronous generator is greater than the phase angle of the inertia center of the power grid.

[0077] The calculation period and stability indicator determination module is used to determine the calculation period and stability indicator of transient power angle stability evaluation index based on the phase angle difference of the inertia center between synchronous generator groups and the maximum phase angle difference of synchronous generators at each simulation time point.

[0078] The time period evaluation index calculation module is used to calculate the power grid inertia center frequency and synchronous generator frequency and inertia at each simulation time point within the time period based on the transient power angle stability evaluation index, and to calculate the transient power angle stability evaluation index for each time period.

[0079] The final evaluation index and stability indicator determination module is used to determine the final transient power angle stability evaluation index and stability indicator after a preset disturbance under the preset power grid operating state, based on the transient power angle stability evaluation index and stability indicator for each time period.

[0080] In an optional implementation, the method for calculating the transient power angle stability assessment index based on point-by-point grouping includes: a) obtaining the phase angle and frequency of synchronous generators at each simulation time point during the transient process after a preset disturbance under a preset power grid operating state; b) calculating the inertia center phase angle and inertia center frequency of the power grid at each simulation time point; c) grouping the synchronous generators at each simulation time point according to whether the phase angle of the synchronous generator is greater than the inertia center phase angle of the power grid; d) determining the calculation period and stability indicator of the transient power angle stability assessment index; e) calculating the transient power angle stability assessment index for each period; f) determining the final transient power angle stability assessment index and stability indicator after a preset disturbance under a preset power grid operating state.

[0081] Example 3

[0082] Please see Figure 3 , Figure 3 This is a schematic diagram of the structure of a transient power angle stability evaluation index calculation device based on point-by-point grouping disclosed in an embodiment of the present invention. Figure 3 The described device can be applied to power systems, such as for power system transient stability analysis, and the embodiments of the present invention are not limited thereto.

[0083] like Figure 3 As shown, the device may include a processor and a memory, the memory storing computer instructions, and the processor executing the computer instructions stored in the memory. When the computer instructions are executed by the processor, the electronic device implements the steps of the method described in the above embodiments and achieves the same technical effect as the above method.

[0084] The memory may include computer system readable media in the form of volatile memory, such as random access memory (RAM) and / or cache memory. The device may further include other removable / non-removable, volatile / non-volatile computer system storage media. By way of example only, the memory may be used to read and write non-removable, non-volatile magnetic media (commonly referred to as a "hard disk drive"). A program / utility having a set (at least one) of program modules may be stored in, for example, memory. Such program modules include, but are not limited to, an operating system, one or more application programs, other program modules, and program data. Each or some combination of these examples may include an implementation of a network environment. The program modules typically perform the functions and / or methods described in the embodiments of the present invention.

[0085] The processor executes various functional applications and data processing by running programs stored in memory, such as the method provided in Embodiment 1 of the present invention.

[0086] Example 4

[0087] Embodiment 4 of the present invention also provides a computer-readable storage medium storing a computer program thereon. When the program is executed by a processor, it implements the steps of the method described in the above embodiments and achieves the same technical effect as the above method.

[0088] The computer storage medium of this invention can be any combination of one or more computer-readable media. A computer-readable medium can be a computer-readable signal medium or a computer-readable storage medium. A computer-readable storage medium can be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of computer-readable storage media (a non-exhaustive list) include: an electrical connection having one or more wires, a portable computer disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination thereof. In this document, a computer-readable storage medium can be any tangible medium that contains or stores a program that can be used by or in conjunction with an instruction execution system, apparatus, or device.

[0089] Computer-readable signal media may include data signals propagated in baseband or as part of a carrier wave, carrying computer-readable program code. Such propagated data signals may take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. Computer-readable signal media may also be any computer-readable medium other than computer-readable storage media, capable of sending, propagating, or transmitting programs for use by or in connection with an instruction execution system, apparatus, or device.

[0090] Program code contained on a computer-readable medium may be transmitted using any suitable medium, including but not limited to wireless, wire, optical fiber, RF, etc., or any suitable combination thereof.

[0091] Computer program code for performing the operations of this invention can be written in one or more programming languages ​​or a combination thereof. Programming languages ​​include object-oriented programming languages ​​such as Java, Smalltalk, and C++, as well as conventional procedural programming languages ​​such as C or similar languages. The program code can be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving remote computers, the remote computer can be connected to the user's computer via any type of network, including a local area network (LAN) or a wide area network (WAN), or it can be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0092] Of course, the computer-executable instructions provided in the embodiments of the present invention are not limited to the above-described method operations, but can also perform related operations in the methods provided in any embodiment of the present invention.

[0093] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for calculating transient power angle stability evaluation index based on point-by-point grouping, characterized in that, include: The inertia, phase angle, and frequency of the synchronous generator at each simulation time point are obtained based on time-domain simulation during the transient process after a preset disturbance under the preset power grid operating state. Based on the inertia, phase angle, and frequency of the synchronous generator at each simulation time point, calculate the inertia center phase angle and inertia center frequency of the power grid at each simulation time point. For each simulation time point, the synchronous generators at each simulation time point are grouped according to whether the phase angle of the synchronous generator is greater than the phase angle of the inertia center of the power grid. Based on the phase angle difference of the inertia center between synchronous generator groups and the maximum phase angle difference of synchronous generators at each simulation time point, the calculation period and stability indicator of transient power angle stability evaluation index are determined. Based on the transient power angle stability assessment index, the power grid inertia center frequency and synchronous generator frequency and inertia at each simulation time point within the time period are calculated, and the transient power angle stability assessment index for each time period is calculated. Based on the transient power angle stability assessment index and stability indicator for each time period, the final transient power angle stability assessment index and stability indicator after the preset disturbance under the preset power grid operating state are determined.

2. The method for calculating transient power angle stability evaluation index based on point-by-point grouping according to claim 1, characterized in that, The formulas for calculating the inertia center phase angle and inertia center frequency of the power grid at each simulation time point are as follows: In the formula, θ i ω i These represent the phase angle and frequency of the power grid's inertia center at the i-th simulation time point, respectively; G i M represents the complete set of synchronous generators in the power grid at the i-th simulation time point; i.g θ i.g ω i.g Let be the inertia, phase angle, and frequency of the synchronous generator g at the i-th simulation time point, respectively.

3. The method for calculating transient power angle stability evaluation index based on point-by-point grouping according to claim 1, characterized in that, For each simulation time point, the synchronous generators at each simulation time point are grouped according to whether their phase angle is greater than the phase angle of the grid's inertia center, including: The complete set G of synchronous generators in the power grid at the i-th simulation time point i The phase angle of the synchronous generator is greater than the phase angle θ of the grid inertia center. i The set of all synchronous generators is called the phase-leading synchronous generator set G at the i-th simulation time point. i.u ,Will The phase lag synchronous generator set G at the i-th simulation time point i.d .

4. The method for calculating transient power angle stability evaluation index based on point-by-point grouping according to claim 1, characterized in that, Based on the phase angle difference of the inertia centers among the synchronous generator groups and the maximum phase angle difference of the synchronous generators at each simulation time point, the calculation period and stability indicators for the transient power angle stability assessment index are determined, including: The phase angle difference θ between the inertia centers of the synchronous generator group at the i-th simulation time point is calculated using the following formula. i.ud The phase angle difference of the inertia center between the synchronous generator groups at each simulation time point was obtained; Among them, G i.u M represents the leading synchronous generator set at the i-th simulation time point; i.g θ i.g These represent the inertia and phase angle of the synchronous generator g at the i-th simulation time point; G i.d For the phase-lag synchronous generator set at the i-th simulation time point; The simulation point at which the phase angle difference between the inertia centers of the synchronous generator groups reaches its extreme value in each simulation time point is taken as the critical simulation time point. The simulation point at which the maximum phase angle difference of the synchronous generator first exceeds the set value for transient power angle instability judgment in each simulation point is taken as the critical simulation point; The number of key simulation time points is used as the number of calculation periods for the transient power angle stability evaluation index. Based on the timing of the key simulation time points during the transient process, the period between the first simulation time point and the first key simulation time point during the transient process is used as the calculation period for the first transient power angle stability evaluation index. The period between the first key simulation time point and the second key simulation time point is used as the calculation period for the second transient power angle stability evaluation index, and so on. The period between the second-to-last key simulation time point and the last key simulation time point is used as the calculation period for the last transient power angle stability evaluation index. If the maximum phase angle difference of the synchronous generator at each simulation point in the calculation period of the transient power angle stability evaluation index is not greater than the transient power angle instability judgment setting value, then the stability flag for that period is set to stable; otherwise, the stability flag for that period is set to unstable.

5. The method for calculating transient power angle stability evaluation index based on point-by-point grouping according to claim 1, characterized in that, The calculation formulas for the transient power angle stability assessment indicators for each time period are as follows: In the formula, x i η represents the kinetic energy deviation rate of all synchronous generators in the power grid relative to the center frequency of inertia at the i-th simulation time point; j For the calculation of the transient power angle stability assessment index, I is the transient power angle stability assessment index corresponding to the j-th transient power angle stability assessment index; j.s I j.e These represent the start and end times of the simulation time corresponding to the calculation period of the j-th transient power angle stability evaluation index; Δt i Let be the duration between the i-th simulation time point and the (i+1)-th simulation time point; ω up ω dn These are the upper and lower limits of the set transient frequency safety values; G i.u G represents the leading synchronous generator set at the i-th simulation time point; i.d For the phase lag synchronous generator set at the i-th simulation time point; ω i ω is the center frequency of the power grid's inertia at the i-th simulation time point; i.g M is the frequency of the synchronous generator g at the i-th simulation time point; i.g Let g be the inertia of the synchronous generator g at the i-th simulation time point.

6. The method for calculating transient power angle stability evaluation index based on point-by-point grouping according to claim 1, characterized in that, Based on the transient power angle stability assessment indicators and stability indicators for each time period, the final transient power angle stability assessment indicators and stability indicators after a preset disturbance under the preset power grid operating state are determined, including: If the transient power angle stability flag is stable in all time periods, the maximum value is extracted from the evaluation index of all time periods and used as the final transient power angle stability evaluation index after the preset disturbance under the preset power grid operating state, and the final stability flag is set to stable; otherwise, the evaluation index of the time period with the transient power angle stability flag as unstable is used as the final transient power angle stability evaluation index after the preset disturbance under the preset power grid operating state, and the final stability flag is set to unstable.

7. The method for calculating transient power angle stability evaluation index based on point-by-point grouping according to claim 1, characterized in that, The synchronous generator includes conventional synchronous generators and virtual synchronous generators.

8. A transient power angle stability evaluation index calculation system based on point-by-point grouping, characterized in that, include: The time-domain simulation module is used to obtain the inertia, phase angle, and frequency of the synchronous generator at each simulation time point in the transient process after a preset disturbance under the preset power grid operating state based on time-domain simulation. The inertia center phase angle and frequency calculation module is used to calculate the inertia center phase angle and inertia center frequency of the power grid at each simulation time point based on the inertia, phase angle and frequency of the synchronous generator at each simulation time point. The synchronous generator grouping module is used to group synchronous generators at each simulation time point based on whether the phase angle of the synchronous generator is greater than the phase angle of the inertia center of the power grid. The calculation period and stability indicator determination module is used to determine the calculation period and stability indicator of transient power angle stability evaluation index based on the phase angle difference of the inertia center between synchronous generator groups and the maximum phase angle difference of synchronous generators at each simulation time point. The time period evaluation index calculation module is used to calculate the power grid inertia center frequency and synchronous generator frequency and inertia at each simulation time point within the time period based on the transient power angle stability evaluation index, and to calculate the transient power angle stability evaluation index for each time period. The final evaluation index and stability indicator determination module is used to determine the final transient power angle stability evaluation index and stability indicator after a preset disturbance under the preset power grid operating state, based on the transient power angle stability evaluation index and stability indicator for each time period.

9. A device for calculating transient power angle stability evaluation index based on point-by-point grouping, characterized in that, The device includes a processor and a memory, wherein the memory stores computer instructions, and the processor executes the computer instructions stored in the memory. When the computer instructions are executed by the processor, the device implements the steps of the transient power angle stability evaluation index calculation method based on point-by-point grouping as described in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, implements the steps of the transient power angle stability evaluation index calculation method based on point-by-point grouping as described in any one of claims 1 to 7.

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