Method and system for calculating transient power angle stability margin of power system

Abstract

The application discloses a kind of power system transient power angle stability margin calculation method and system, including determining the corresponding energy balance fulcrum of each simulation time point after disturbance;For each time point, two synchronous generator sets are divided into two synchronous generator sets with energy balance fulcrum as boundary, according to the difference between the rotor inertia center angle of two synchronous generator sets, the lead or lag attribute of synchronous generator set is determined;According to the difference between the rotor inertia center angle of lead generator set and lag generator set, the time period and sub-period of stability margin calculation are determined;According to the rotor inertia center frequency of all time points in each sub-period, the rotational inertia of synchronous generator and frequency and time point number, the transient power angle stability margin corresponding to each sub-period is calculated, and the minimum value is taken as the transient power angle stability margin of power grid after disturbance. The corresponding system is also disclosed. The application provides a basis for quantitative evaluation of power system transient power angle stability under different operating conditions after different disturbances.

Description

Technical Field

[0001] This invention relates to a method and system for calculating transient power angle stability margin in a power system, belonging to the field of power system stability analysis technology. Background Technology

[0002] A method for calculating the transient power angle stability margin of a power system based on the extended equal area criterion has been applied in engineering. This method maps the operating trajectories of all synchronous generators in the disturbed power system to a series of time-varying single-machine infinite bus (OMIB) mapping trajectories through a complementary group inertia center-relative motion transformation. Then, based on the power-angle curves of the OMIBs, the stability margin of each OMIB mapping is determined by calculating the kinetic energy acceleration area and kinetic energy deceleration area. The minimum stability margin is taken as the transient power angle stability margin of the power system after the disturbance. However, this method groups synchronous generators based on the entire transient process, without distinguishing the differences in the impact of different generator groupings on transient power angle stability at different points in time. Furthermore, for stable mapping trajectories, this method requires extrapolating the electromagnetic power-angle curves and mechanical power-angle curves of equivalent generators, using the potential kinetic energy reduction area as the transient power angle stability margin of the power system after the disturbance. Summary of the Invention

[0003] The technical problem to be solved by this invention is: in the process of calculating the transient power angle stability margin of a power system, how to dynamically group synchronous generators at each simulation point in the transient process, and directly calculate the transient power angle stability margin of the power system after the disturbance based on the essential characteristic of synchronous generators in the power grid maintaining synchronous operation.

[0004] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0005] Firstly, a method for calculating the transient power angle stability margin of a power system is provided, including:

[0006] For the preset power grid operating state, determine the power grid energy balance pivot point corresponding to each simulation time point after the preset disturbance;

[0007] For each simulation time point, the synchronous generators are divided into two sets of synchronous generators with the grid energy balance support point as the boundary, thus obtaining the two sets of synchronous generators corresponding to each simulation time point;

[0008] For each simulation time point, the rotor inertia center angle of the two synchronous generator sets is calculated. The synchronous generator set with the larger rotor inertia center angle is defined as the leading synchronous generator set, and the synchronous generator set with the smaller rotor inertia center angle is defined as the lagging synchronous generator set.

[0009] Based on the difference in rotor inertia center angle between the leading synchronous generator set and the lagging synchronous generator set at each simulation time point, the time period and sub-time period for calculating the transient power angle stability margin of the power grid are determined.

[0010] Based on the transient power angle stability margin of the power grid, the rotational inertia and frequency of the synchronous generator in the power grid at each simulation time point during the calculation period are calculated, and the center frequency of the rotor inertia of the synchronous generator in the power grid at each simulation time point is calculated.

[0011] Based on the transient power angle stability margin of the power grid, calculate the rotor inertia center frequency, synchronous generator rotational inertia and frequency, and simulation time point of the synchronous generator in the power grid at all simulation time points in each sub-period, and calculate the transient power angle stability margin of the power grid corresponding to that sub-period.

[0012] The minimum value among the transient power angle stability margins of the power grid corresponding to each sub-period is taken as the transient power angle stability margin of the power grid after the disturbance.

[0013] In some embodiments, for a preset power grid operating state, determining the power grid energy balance pivot point corresponding to each simulation time point after a preset disturbance includes:

[0014] Time-domain simulations of preset disturbances are performed for preset power grid operating conditions to obtain admittance matrices for network equation calculation at each simulation time point after the preset disturbance.

[0015] For the admittance matrix used for network equation calculation at each simulation time point, the power grid is converted into a 3-node, 5-branch network that meets the set conditions through static network equivalence. The nodes include two equivalent power source nodes and one equivalent load node. The network branches include three ground-connected branches of the nodes and two branches between the equivalent power source nodes and the equivalent load node. The set condition is that the current injected from the two equivalent power source nodes into the equivalent load node is equal.

[0016] For each simulation time point, the position of the equivalent load node in the pre-equivalence power grid is determined by backtracking the static network equivalent process, and this position is used as the energy balance fulcrum of the power grid.

[0017] For each simulation time point, the rotor inertia center angles of the synchronous generators in the two synchronous generator sets are calculated. The synchronous generator set with the larger rotor inertia center angle is defined as the leading synchronous generator set, and the synchronous generator set with the smaller rotor inertia center angle is defined as the lagging synchronous generator set, including:

[0018]

[0019]

[0020] In the formula, A i B iThese are the two sets of synchronous generators corresponding to the i-th simulation time point. A respectively i B i The rotor inertia center angle of the synchronous generator at the i-th simulation time point, M i.a δ i.a A respectively i The moment of inertia and internal electromotive force phase angle of the synchronous generator at the i-th simulation time point, M i.b δ i.b B respectively i The moment of inertia and internal electromotive force phase angle of the synchronous generator b at the i-th simulation time point.

[0021] In some embodiments, the time period and sub-time period for calculating the transient power angle stability margin of the power grid are determined based on the difference in the rotor inertia center angle between the leading synchronous generator set and the lagging synchronous generator set at each simulation time point, including:

[0022] If the i-th simulation time point corresponds to A i For the leading synchronous generator set, the difference δ between the rotor inertia center angles of the leading synchronous generator set and the lagging synchronous generator set at the i-th simulation time point is calculated. i Set as Otherwise, the difference δ between the rotor inertia center angles of the leading synchronous generator set and the lagging synchronous generator set corresponding to the i-th simulation time point is calculated. i Set as

[0023] For each simulation time point δ i The time series data consists of at least one data point greater than or equal to δ. s Then, record the minimum value of the sequence number corresponding to the data as I. e And will be in I e Previously and with I e The index record corresponding to the nearest extreme point is I. s The start and end numbers corresponding to the time period for calculating the transient power angle stability margin of the power grid are determined as I. s and I e There is one sub-time period, and the start and end numbers of the sub-time period are I and I, respectively. s and I eOtherwise, record the number of extreme points as M, sort the extreme points in ascending order of their corresponding serial numbers, and determine the starting and ending serial numbers of the time period for calculating the transient power angle stability margin of the power grid as 1 and the serial number corresponding to the Mth extreme point, respectively. There are M sub-time periods. The starting and ending serial numbers of the first sub-time period are 1 and the serial number corresponding to the first extreme point, respectively. The starting and ending serial numbers of the second sub-time period are the serial numbers corresponding to the first and second extreme points, respectively. And so on, the starting and ending serial numbers of the Mth sub-time period are the serial numbers corresponding to the (M-1)th and Mth extreme points, respectively.

[0024] Where, δ s To set parameters.

[0025] In some embodiments, the moment of inertia and frequency of the synchronous generator in the power grid at each simulation point in time are calculated based on the transient power angle stability margin of the power grid, and the center frequency of the rotor inertia of the synchronous generator in the power grid at each simulation point in time is calculated, including:

[0026]

[0027] In the formula, ω j.k Let M be the rotor inertia center frequency of the synchronous generator in the power grid at the k-th simulation time point within the j-th sub-period of the power grid transient power angle stability margin calculation period, G be the total set of synchronous generators in the power grid, and M be the frequency of the synchronous generator in the power grid. j.k.g ω j.k.g These represent the moment of inertia and frequency of the synchronous generator g in G at the k-th simulation time point within the j-th sub-period of the power grid transient power angle stability margin calculation period.

[0028] In some embodiments, based on the transient power angle stability margin of the power grid, the rotor inertia center frequency, the moment of inertia and frequency of the synchronous generator in the power grid at all simulation time points within each sub-period are calculated, along with the number of simulation time points. The transient power angle stability margin of the power grid corresponding to that sub-period is then calculated, including:

[0029]

[0030] In the formula, η j Let α and β be the transient power angle stability margin of the power grid corresponding to the j-th sub-period of the calculation period, where β is greater than 0. j.s I j.e These are the start and end numbers of the j-th sub-period corresponding to the calculation period of the power grid transient power angle stability margin, respectively. j.k D j.kThese represent the leading and lagging synchronous generator sets corresponding to the k-th simulation time point within the j-th sub-period of the power grid transient power angle stability margin calculation period, respectively. G is the complete set of synchronous generators in the power grid, and M is the leading and lagging synchronous generator sets corresponding to the k-th simulation time point within the j-th sub-period of the power grid transient power angle stability margin calculation period. j.k.g ω j.k.g These represent the moment of inertia and frequency of the synchronous generator g in G at the k-th simulation time point within the j-th sub-period of the power grid transient power angle stability margin calculation period, respectively. j.k ω is the rotor inertia center frequency of the synchronous generator in the power grid at the k-th simulation time point within the j-th sub-period of the power grid transient power angle stability margin calculation period. up.g ω dn.g These are the upper and lower limits of the transient frequency safety for the synchronous generator g, respectively.

[0031] In some embodiments, when the pre-set power grid under the preset power grid operating state is composed of two or more asynchronous sub-power grids after a preset disturbance, each asynchronous sub-power grid is processed independently.

[0032] Secondly, a power system transient power angle stability margin calculation system is provided, including,

[0033] Energy balance pivot point determination module: For a preset power grid operating state, determine the power grid energy balance pivot point corresponding to each simulation time point after a preset disturbance;

[0034] Synchronous generator set generation module: For each simulation time point, the synchronous generator is divided into two synchronous generator sets with the grid energy balance support point as the boundary, and the two synchronous generator sets corresponding to each simulation time point are obtained.

[0035] Synchronous generator set attribute determination module: For each simulation time point, calculate the rotor inertia center angle of the generators in the two synchronous generator sets, and define the synchronous generator set with the larger rotor inertia center angle as the leading synchronous generator set, and the synchronous generator set with the smaller rotor inertia center angle as the lagging synchronous generator set.

[0036] The module for determining the time period and sub-time period for margin calculation is as follows: Based on the difference in the rotor inertia center angle between the leading synchronous generator set and the lagging synchronous generator set at each simulation time point, the time period and sub-time period for calculating the transient power angle stability margin of the power grid are determined.

[0037] Rotor inertia center frequency calculation module: Based on the transient power angle stability margin of the power grid, calculate the rotational inertia and frequency of the synchronous generator in the power grid at each simulation time point, and calculate the rotor inertia center frequency of the synchronous generator in the power grid at each simulation time point;

[0038] Sub-period stability margin calculation module: Based on the power grid transient power angle stability margin, calculate the rotor inertia center frequency, synchronous generator rotational inertia and frequency, and simulation time point of the synchronous generator in the power grid at all simulation time points in each sub-period, and calculate the power grid transient power angle stability margin corresponding to that sub-period;

[0039] Grid stability margin determination module: Take the minimum value of the grid transient power angle stability margin corresponding to each sub-time period as the transient power angle stability margin of the grid after the disturbance.

[0040] Thirdly, a computer-readable storage medium is provided for storing one or more programs, the one or more programs including instructions that, when executed by a computing device, cause the computing device to perform a method for calculating the transient power angle stability margin of a power system.

[0041] Fourthly, a computing device is provided, comprising one or more processors, one or more memories, and one or more programs, wherein the one or more programs are stored in the one or more memories and configured to be executed by the one or more processors, and the one or more programs include instructions for performing a method for calculating the transient power angle stability margin of a power system.

[0042] The beneficial effects achieved by this invention are as follows: This invention considers the differences in the impact of different synchronous generator groupings at various points in time on the transient power angle stability of the power grid. Based on the power grid energy balance pivot point during the transient process, the synchronous generators are dynamically grouped. According to the kinetic energy deviation of the leading and lagging synchronous generators relative to the rotor inertia centers of all synchronous generators during the transient process, a transient power angle stability margin evaluation index for the power system is designed. This is in line with the essential characteristic requirement of synchronous generators in the power grid to maintain synchronous operation, and provides a basis for the quantitative evaluation of the transient power angle stability of the power system under different operating conditions and after different disturbances. Attached Figure Description

[0043] Figure 1 This is a flowchart of a method according to an embodiment of the present invention. Detailed Implementation

[0044] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0045] Example 1

[0046] like Figure 1 As shown, the method for calculating the transient power angle stability margin of a power system includes the following steps:

[0047] Step 1: For the preset power grid operating state, determine the power grid energy balance pivot point corresponding to each simulation time point after the preset disturbance.

[0048] The specific process is as follows:

[0049] 11) Perform time-domain simulation of preset disturbances for preset power grid operating conditions, and obtain the admittance matrix for network equation calculation at each simulation time point after the preset disturbance;

[0050] 12) For the admittance matrix used for network equation calculation at each simulation time point, the power grid is converted into a 3-node, 5-branch network that meets the set conditions through static network equivalence. The nodes include two equivalent power supply nodes and one equivalent load node. The network branches include three ground-connected branches of the nodes and two branches between the equivalent power supply nodes and the equivalent load node. The set condition is that the current injected into the equivalent load node by the two equivalent power supply nodes is equal.

[0051] 13) For each simulation time point, the position of the equivalent load node in the pre-equivalence power grid is determined by backtracking the static network equivalent process, and this position is used as the energy balance support point of the power grid.

[0052] The grid energy balance pivot point changes dynamically during transient processes, and there is a corresponding grid energy balance pivot point at each simulation point in time.

[0053] Step 2: For each simulation time point, divide the synchronous generators into two synchronous generator sets with the grid energy balance pivot as the boundary, and obtain the two synchronous generator sets corresponding to each simulation time point.

[0054] Step 3: For each simulation time point, calculate the rotor inertia center angle of the two synchronous generator sets. Define the synchronous generator set with the larger rotor inertia center angle as the leading synchronous generator set, and define the synchronous generator set with the smaller rotor inertia center angle as the lagging synchronous generator set.

[0055] The specific calculation formula is as follows:

[0056]

[0057]

[0058] In the formula, A i B i These are the two sets of synchronous generators corresponding to the i-th simulation time point. A respectively i B i The rotor inertia center angle of the synchronous generator at the i-th simulation time point, M i.a δ i.a A respectively i The moment of inertia and internal electromotive force phase angle of the synchronous generator at the i-th simulation time point, M i.b δ i.b B respectivelyi The moment of inertia and internal electromotive force phase angle of the synchronous generator b at the i-th simulation time point.

[0059] Step 4: Based on the difference in rotor inertia center angle between the leading synchronous generator set and the lagging synchronous generator set at each simulation time point, determine the time period and sub-time period for calculating the transient power angle stability margin of the power grid.

[0060] The specific process is as follows:

[0061] 41) If the A corresponding to the i-th simulation time point i For the leading synchronous generator set, the difference δ between the rotor inertia center angles of the leading synchronous generator set and the lagging synchronous generator set at the i-th simulation time point is calculated. i Set as Otherwise, the difference δ between the rotor inertia center angles of the leading synchronous generator set and the lagging synchronous generator set corresponding to the i-th simulation time point is calculated. i Set as

[0062] 42) For each simulation time point δ i The time series data consists of at least one data point greater than or equal to δ. s Then, record the minimum value of the sequence number corresponding to the data as I. e And will be in I e Previously and with I e The index record corresponding to the nearest extreme point is I. s The start and end numbers corresponding to the time period for calculating the transient power angle stability margin of the power grid are determined as I. s and I e There is one sub-time period, and the start and end numbers of the sub-time period are I and I, respectively. s and I e Otherwise, record the number of extreme points as M, sort the extreme points in ascending order of their corresponding serial numbers, and determine the starting and ending serial numbers of the time period for calculating the transient power angle stability margin of the power grid as 1 and the serial number corresponding to the Mth extreme point, respectively. There are M sub-time periods. The starting and ending serial numbers of the first sub-time period are 1 and the serial number corresponding to the first extreme point, respectively. The starting and ending serial numbers of the second sub-time period are the serial numbers corresponding to the first and second extreme points, respectively. And so on, the starting and ending serial numbers of the Mth sub-time period are the serial numbers corresponding to the (M-1)th and Mth extreme points, respectively.

[0063] Where, δ s To set the parameters, it is usually set to 180°.

[0064] Step 5: Calculate the moment of inertia and frequency of the synchronous generator in the power grid at each simulation point in time based on the transient power angle stability margin of the power grid, and calculate the center frequency of the rotor inertia of the synchronous generator in the power grid at each simulation point in time.

[0065] The specific calculation formula is as follows:

[0066]

[0067] In the formula, ω j.k Let M be the rotor inertia center frequency of the synchronous generator in the power grid at the k-th simulation time point within the j-th sub-period of the power grid transient power angle stability margin calculation period, G be the total set of synchronous generators in the power grid, and M be the frequency of the synchronous generator in the power grid. j.k.g ω j.k.g These represent the moment of inertia and frequency of the synchronous generator g in G at the k-th simulation time point within the j-th sub-period of the power grid transient power angle stability margin calculation period.

[0068] Step 6: Calculate the rotor inertia center frequency, synchronous generator moment of inertia and frequency, and simulation time point number of the synchronous generator in the power grid at all simulation time points within each sub-period based on the power grid transient power angle stability margin. Calculate the power grid transient power angle stability margin corresponding to that sub-period.

[0069] The specific calculation formula is as follows:

[0070]

[0071] In the formula, η j This refers to the transient power angle stability margin of the power grid corresponding to the j-th sub-period in the calculation period of the power grid transient power angle stability margin. α and β are set parameters, where β is greater than 0, α is usually set to 1, and β is usually set to 2. j.s I j.e These are the start and end numbers of the j-th sub-period corresponding to the calculation period of the power grid transient power angle stability margin, respectively. j.k D j.k These represent the leading and lagging synchronous generator sets corresponding to the k-th simulation time point within the j-th sub-period of the power grid transient power angle stability margin calculation period, respectively. G is the complete set of synchronous generators in the power grid, and M is the leading and lagging synchronous generator sets corresponding to the k-th simulation time point within the j-th sub-period of the power grid transient power angle stability margin calculation period. j.k.g ω j.k.g These represent the moment of inertia and frequency of the synchronous generator g in G at the k-th simulation time point within the j-th sub-period of the power grid transient power angle stability margin calculation period, respectively. j.k ω is the rotor inertia center frequency of the synchronous generator in the power grid at the k-th simulation time point within the j-th sub-period of the power grid transient power angle stability margin calculation period. up.g ω dn.gThese are the upper and lower limits of the transient frequency safety for the synchronous generator g, respectively. They are usually set to 1.02 times and 0.96 times the rated frequency of the synchronous generator, respectively. Different upper and lower limits of transient frequency safety can also be set according to the different requirements of the synchronous generator for transient frequency safety.

[0072] Step 7: Take the minimum value of the transient power angle stability margin of the power grid corresponding to each sub-time period as the transient power angle stability margin of the power grid after the disturbance.

[0073] For cases where the pre-set power grid is composed of two or more asynchronous sub-grids after a pre-set disturbance under the pre-set power grid operating state, each asynchronous sub-grid is handled independently.

[0074] The larger the transient power angle stability margin of the power grid obtained by the above method, the higher the transient power angle stability of the power grid. Conversely, the smaller the transient power angle stability margin of the power grid, the lower the transient power angle stability of the power grid.

[0075] The above method enables the calculation of the transient power angle stability margin of the power system, providing a basis for the quantitative assessment of the transient power angle stability of the power system under different operating conditions and after different disturbances.

[0076] Example 2

[0077] A power system transient power angle stability margin calculation system includes,

[0078] Energy balance pivot point determination module: For a preset power grid operating state, determine the power grid energy balance pivot point corresponding to each simulation time point after a preset disturbance;

[0079] Synchronous generator set generation module: For each simulation time point, the synchronous generator is divided into two synchronous generator sets with the grid energy balance support point as the boundary, and the two synchronous generator sets corresponding to each simulation time point are obtained.

[0080] Synchronous generator set attribute determination module: For each simulation time point, calculate the rotor inertia center angle of the generators in the two synchronous generator sets, and define the synchronous generator set with the larger rotor inertia center angle as the leading synchronous generator set, and the synchronous generator set with the smaller rotor inertia center angle as the lagging synchronous generator set.

[0081] The module for determining the time period and sub-time period for margin calculation is as follows: Based on the difference in the rotor inertia center angle between the leading synchronous generator set and the lagging synchronous generator set at each simulation time point, the time period and sub-time period for calculating the transient power angle stability margin of the power grid are determined.

[0082] Rotor inertia center frequency calculation module: Based on the transient power angle stability margin of the power grid, calculate the rotational inertia and frequency of the synchronous generator in the power grid at each simulation time point, and calculate the rotor inertia center frequency of the synchronous generator in the power grid at each simulation time point;

[0083] Sub-period stability margin calculation module: Based on the power grid transient power angle stability margin, calculate the rotor inertia center frequency, synchronous generator rotational inertia and frequency, and simulation time point of the synchronous generator in the power grid at all simulation time points in each sub-period, and calculate the power grid transient power angle stability margin corresponding to that sub-period;

[0084] Grid stability margin determination module: Take the minimum value of the grid transient power angle stability margin corresponding to each sub-time period as the transient power angle stability margin of the grid after the disturbance.

[0085] Example 3

[0086] A computer-readable storage medium storing one or more programs, the one or more programs including instructions that, when executed by a computing device, cause the computing device to perform the power system transient power angle stability margin calculation method described in Embodiment 1.

[0087] Example 4

[0088] A computing device includes one or more processors, one or more memories, and one or more programs, wherein the one or more programs are stored in the one or more memories and configured to be executed by the one or more processors, and the one or more programs include instructions for executing the method for calculating the transient power angle stability margin of a power system as described in Embodiment 1.

[0089] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0090] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0091] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0092] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0093] The above are merely 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 are included within the scope of the claims of the present invention pending approval.

Claims

1. A method for calculating the transient power angle stability margin of a power system, characterized in that, include: For the preset power grid operating state, determine the power grid energy balance pivot point corresponding to each simulation time point after the preset disturbance; For each simulation time point, the synchronous generators are divided into two sets of synchronous generators with the grid energy balance support point as the boundary, thus obtaining the two sets of synchronous generators corresponding to each simulation time point; For each simulation time point, the rotor inertia center angle of the two synchronous generator sets is calculated. The synchronous generator set with the larger rotor inertia center angle is defined as the leading synchronous generator set, and the synchronous generator set with the smaller rotor inertia center angle is defined as the lagging synchronous generator set. Based on the difference in rotor inertia center angle between the leading synchronous generator set and the lagging synchronous generator set at each simulation time point, the time period and sub-time period for calculating the transient power angle stability margin of the power grid are determined. Based on the transient power angle stability margin of the power grid, the rotational inertia and frequency of the synchronous generator in the power grid at each simulation time point during the calculation period are calculated, and the center frequency of the rotor inertia of the synchronous generator in the power grid at each simulation time point is calculated. Based on the transient power angle stability margin of the power grid, calculate the rotor inertia center frequency, synchronous generator moment of inertia and frequency, and simulation time point of the synchronous generator in the power grid at all simulation time points within each sub-period. Calculate the corresponding transient power angle stability margin of the power grid for that sub-period, including: In the formula, η j Let α and β be the transient power angle stability margin of the power grid corresponding to the j-th sub-period of the calculation period, where β is greater than 0. j.s I j.e These are the start and end numbers of the j-th sub-period corresponding to the calculation period of the power grid transient power angle stability margin, respectively. j.k D j.k These represent the leading and lagging synchronous generator sets corresponding to the k-th simulation time point within the j-th sub-period of the power grid transient power angle stability margin calculation period, respectively. G is the complete set of synchronous generators in the power grid, and M is the leading and lagging synchronous generator sets corresponding to the k-th simulation time point within the j-th sub-period of the power grid transient power angle stability margin calculation period. j.k.g ω j.k.g These represent the moment of inertia and frequency of the synchronous generator g in G at the k-th simulation time point within the j-th sub-period of the power grid transient power angle stability margin calculation period, respectively. j.k ω is the rotor inertia center frequency of the synchronous generator in the power grid at the k-th simulation time point within the j-th sub-period of the power grid transient power angle stability margin calculation period. up.g ω dn.g These are the upper and lower limits of the transient frequency safety for the synchronous generator g, respectively. The minimum value among the transient power angle stability margins of the power grid corresponding to each sub-period is taken as the transient power angle stability margin of the power grid after the disturbance.

2. The method for calculating the transient power angle stability margin of a power system according to claim 1, characterized in that: For a preset power grid operating state, determine the power grid energy balance pivot points corresponding to each simulation time point after the preset disturbance, including: Time-domain simulations of preset disturbances are performed for preset power grid operating conditions to obtain admittance matrices for network equation calculation at each simulation time point after the preset disturbance. For the admittance matrix used for network equation calculation at each simulation time point, the power grid is converted into a 3-node, 5-branch network that meets the set conditions through static network equivalence. The nodes include two equivalent power source nodes and one equivalent load node. The network branches include three ground-connected branches of the nodes and two branches between the equivalent power source nodes and the equivalent load node. The set condition is that the current injected from the two equivalent power source nodes into the equivalent load node is equal. For each simulation time point, the position of the equivalent load node in the pre-equivalence power grid is determined by backtracking the static network equivalent process, and this position is used as the energy balance fulcrum of the power grid.

3. The method for calculating the transient power angle stability margin of a power system according to claim 1, characterized in that: For each simulation time point, the rotor inertia center angles of the synchronous generators in the two synchronous generator sets are calculated. The synchronous generator set with the larger rotor inertia center angle is defined as the leading synchronous generator set, and the synchronous generator set with the smaller rotor inertia center angle is defined as the lagging synchronous generator set, including: In the formula, A i B i These are the two sets of synchronous generators corresponding to the i-th simulation time point. A respectively i B i The rotor inertia center angle of the synchronous generator at the i-th simulation time point, M i.a δ i.a A respectively i The moment of inertia and internal electromotive force phase angle of the synchronous generator at the i-th simulation time point, M i.b δ i.b B respectively i The moment of inertia and internal electromotive force phase angle of the synchronous generator b at the i-th simulation time point.

4. The method for calculating the transient power angle stability margin of a power system according to claim 1 or 3, characterized in that: Based on the difference in rotor inertia center angle between the leading and lagging synchronous generator sets at each simulation time point, the time period and sub-time period for calculating the transient power angle stability margin of the power grid are determined, including: If the i-th simulation time point corresponds to A i For the leading synchronous generator set, the difference δ between the rotor inertia center angles of the leading synchronous generator set and the lagging synchronous generator set at the i-th simulation time point is calculated. i Set as Otherwise, the difference δ between the rotor inertia center angles of the leading synchronous generator set and the lagging synchronous generator set corresponding to the i-th simulation time point is calculated. i Set as A respectively i B i The rotor inertia center angle of the intermediate synchronous generator at the i-th simulation time point; For each simulation time point δ i The time series data consists of at least one data point greater than or equal to δ. s Then, record the minimum value of the sequence number corresponding to the data as I. e And will be in I e Previously and with I e The index record corresponding to the nearest extreme point is I. s The start and end numbers corresponding to the time period for calculating the transient power angle stability margin of the power grid are determined as I. s and I e There is one sub-time period, and the start and end numbers of the sub-time period are I and I, respectively. s and I e Otherwise, record the number of extreme points as M, sort the extreme points in ascending order of their corresponding serial numbers, and determine the starting and ending serial numbers of the time period for calculating the transient power angle stability margin of the power grid as 1 and the serial number corresponding to the Mth extreme point, respectively. There are M sub-time periods. The starting and ending serial numbers of the first sub-time period are 1 and the serial number corresponding to the first extreme point, respectively. The starting and ending serial numbers of the second sub-time period are the serial numbers corresponding to the first and second extreme points, respectively. And so on, the starting and ending serial numbers of the Mth sub-time period are the serial numbers corresponding to the (M-1)th and Mth extreme points, respectively. Where, δ s To set parameters.

5. The method for calculating the transient power angle stability margin of a power system according to claim 1, characterized in that: Based on the calculation of the transient power angle stability margin of the power grid, the rotational inertia and frequency of the synchronous generators in the power grid at each simulation time point are calculated, including: In the formula, ω j.k Let M be the rotor inertia center frequency of the synchronous generator in the power grid at the k-th simulation time point within the j-th sub-period of the power grid transient power angle stability margin calculation period, G be the total set of synchronous generators in the power grid, and M be the frequency of the synchronous generator in the power grid. j.k.g ω j.k.g These represent the moment of inertia and frequency of the synchronous generator g in G at the k-th simulation time point within the j-th sub-period of the power grid transient power angle stability margin calculation period.

6. The method for calculating the transient power angle stability margin of a power system according to claim 1, characterized in that: For cases where the pre-set power grid is composed of two or more asynchronous sub-grids after a pre-set disturbance under the pre-set power grid operating state, each asynchronous sub-grid is handled independently.

7. A power system transient power angle stability margin calculation system, characterized in that: include, Energy balance pivot point determination module: For a preset power grid operating state, determine the power grid energy balance pivot point corresponding to each simulation time point after a preset disturbance; Synchronous generator set generation module: For each simulation time point, the synchronous generator is divided into two synchronous generator sets with the grid energy balance support point as the boundary, and the two synchronous generator sets corresponding to each simulation time point are obtained. Synchronous generator set attribute determination module: For each simulation time point, calculate the rotor inertia center angle of the generators in the two synchronous generator sets, and define the synchronous generator set with the larger rotor inertia center angle as the leading synchronous generator set, and the synchronous generator set with the smaller rotor inertia center angle as the lagging synchronous generator set. The module for determining the time period and sub-time period for margin calculation is as follows: Based on the difference in the rotor inertia center angle between the leading synchronous generator set and the lagging synchronous generator set at each simulation time point, the time period and sub-time period for calculating the transient power angle stability margin of the power grid are determined. Rotor inertia center frequency calculation module: Based on the transient power angle stability margin of the power grid, calculate the rotational inertia and frequency of the synchronous generator in the power grid at each simulation time point, and calculate the rotor inertia center frequency of the synchronous generator in the power grid at each simulation time point; Sub-period stability margin calculation module: Based on the grid transient power angle stability margin, this module calculates the rotor inertia center frequency, synchronous generator moment of inertia and frequency, and simulation time point number of the synchronous generator in the grid at all simulation time points within each sub-period. It then calculates the corresponding grid transient power angle stability margin for that sub-period, including: In the formula, η j Let α and β be the transient power angle stability margin of the power grid corresponding to the j-th sub-period of the calculation period, where β is greater than 0. j.s I j.e These are the start and end numbers of the j-th sub-period corresponding to the calculation period of the power grid transient power angle stability margin, respectively. j.k D j.k These represent the leading and lagging synchronous generator sets corresponding to the k-th simulation time point within the j-th sub-period of the power grid transient power angle stability margin calculation period, respectively. G is the complete set of synchronous generators in the power grid, and M is the leading and lagging synchronous generator sets corresponding to the k-th simulation time point within the j-th sub-period of the power grid transient power angle stability margin calculation period. j.k.g ω j.k.g These represent the moment of inertia and frequency of the synchronous generator g in G at the k-th simulation time point within the j-th sub-period of the power grid transient power angle stability margin calculation period, respectively. j.k ω is the rotor inertia center frequency of the synchronous generator in the power grid at the k-th simulation time point within the j-th sub-period of the power grid transient power angle stability margin calculation period. up.g ω dn.g These are the upper and lower limits of the transient frequency safety for the synchronous generator g, respectively. Grid stability margin determination module: Take the minimum value of the grid transient power angle stability margin corresponding to each sub-time period as the transient power angle stability margin of the grid after the disturbance.

8. A computer-readable storage medium for storing one or more programs, characterized in that: The one or more programs include instructions that, when executed by a computing device, cause the computing device to perform any of the methods according to claims 1 to 6.

9. A computing device, characterized in that: include, One or more processors, one or more memories, and one or more programs, wherein the one or more programs are stored in the one or more memories and configured to be executed by the one or more processors, the one or more programs including instructions for performing any of the methods according to claims 1 to 6.

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