Transient power angle stability margin calculation method and system

Abstract

The invention discloses a transient power angle stability margin calculation method and system, and the method comprises the steps: carrying out the calculation according to the dynamic response data during the operation fault of a power grid, and obtaining a dominant power division point; equivalence transformation is carried out on the dominant active division point adjacent network, and power grid active balance division point positions corresponding to all time nodes are obtained; the method comprises the following steps: dividing synchronous generators in a power grid into a leading synchronous generator set and a lagging synchronous generator set according to a power grid active balance point; and based on the leading synchronous generator set and the lagging synchronous generator set, obtaining a transient power angle stability margin time period, and calculating the transient power angle stability margin corresponding to the transient power angle stability margin time period. According to the method, the influence of the synchronous generator on the transient power angle stability at each time node is qualitatively judged; an electric power system transient state power angle stability margin evaluation index is designed based on a leading synchronous generator and a lagging synchronous generator, and a basis is provided for transient state power angle stability quantitative evaluation of the electric power system after different operation states and different disturbances.

Description

Technical Field

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

[0002] The increasing complexity and scale of modern power systems have made transient power angle stability margin an indispensable key indicator in power system stability analysis. This indicator assesses the ability of synchronous generators to maintain synchronization and restore stable operation after a large disturbance, directly affecting the safe and stable operation of the power system, power supply quality, and economic benefits. Accurate calculation of transient power angle stability margin is of great significance for preventing large-scale power outages and ensuring power supply.

[0003] Currently, methods for calculating transient power angle stability margin are mainly divided into direct methods and hybrid methods based on time-domain simulation. Direct methods, such as the energy function method and the Lyapunov function method, while computationally fast, have limitations when dealing with complex power system models and are difficult to apply directly to practical engineering. Hybrid methods based on time-domain simulation, such as the extended equal area criterion (EEAC) method, are applicable to complex systems, but their grouping method ignores the time-varying dynamic behavior of generators during transient processes and relies on extrapolating the characteristic curves of equivalent generators based on assumptions, increasing computational uncertainty. Furthermore, high computational complexity is a major challenge for the practical application of this method. Therefore, existing technologies still need improvement in terms of accuracy and practicality. Summary of the Invention

[0004] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0005] In view of the aforementioned existing problems, this invention is proposed. Therefore, this invention provides a method for calculating transient power angle stability margin to solve the problems of inaccurate calculations and high computational complexity in existing technologies when dealing with complex power system models.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0007] In a first aspect, the present invention provides a method for calculating transient power angle stability margin, comprising:

[0008] Acquire dynamic response data during power grid operation faults, and calculate and obtain the dominant active power distribution point based on the dynamic response data during power grid operation faults;

[0009] The dominant active power distribution point neighborhood network is transformed into an equivalent value to obtain the location of the power grid active power balance point at each time node.

[0010] Based on the active power balance points of the power grid, the synchronous generators in the power grid are divided into leading synchronous generator sets and lagging synchronous generator sets.

[0011] Based on the leading synchronous generator set and lagging synchronous generator set corresponding to each time node, the transient power angle stability margin period is obtained, and the transient power angle stability margin corresponding to the transient power angle stability margin period is calculated.

[0012] As a preferred embodiment of the transient power angle stability margin calculation method of the present invention, the calculation of the dominant active power component includes:

[0013] Obtain the network equations and phase angles of the internal potential of the synchronous generators at each time node, calculate the dominant index of each active power distribution point in the power grid at each time node, define the active power distribution point corresponding to the maximum value of the dominant index as the dominant active power distribution point at the current time node, and take the two synchronous generator groups corresponding to the dominant index of the dominant active power distribution point as the two dominant synchronous generator groups at the current time node.

[0014] As a preferred embodiment of the transient power angle stability margin calculation method described in this invention, the formula for calculating the dominant index is:

[0015]

[0016] Among them, L i Let γ be the complete set of active power distribution points at the i-th time node. l.i G is the dominant indicator of the active power distribution point l at the i-th time node. i Let G1 be the complete set of synchronous generators at time point i, and G2 be the two synchronous generator groups corresponding to the dominant index of active power distribution point l at time point i. Let g1 and g2 be the sensitivities of the active power flowing out of active power distribution point l at the i-th time node, respectively. These are the internal potential phase angles of synchronous generator g1 and synchronous generator g2 at the i-th time node, respectively.

[0017] As a preferred embodiment of the transient power angle stability margin calculation method of the present invention, the equivalent transformation of the dominant active power distribution point neighborhood network includes:

[0018] By performing Y-Δ network equivalent transformation on the neighboring network of the dominant active power distribution point, the transformed power grid includes two sub-networks connected by a T-shaped network consisting of 3 equivalent nodes, 2 equivalent branches and 1 equivalent load branch, and the two synchronous generator dominant groups at the current time node are located in different sub-networks;

[0019] The active power flowing into the equivalent load branch from the two equivalent branches is equal, and the electrical distance between the node connected to the equivalent load branch and the dominant active power distribution point is the smallest. The equivalent node connected to the equivalent load branch is taken as the active power balancing distribution point.

[0020] As a preferred embodiment of the transient power angle stability margin calculation method described in this invention, the synchronous generators in the power grid are divided into a leading synchronous generator set and a lagging synchronous generator set, including:

[0021] Based on the backtracking of the network equivalent transformation process, the specific location of the active power balance point on the element in the network before the transformation is obtained. The specific locations of the active power balance point on the element are connected to form the dividing line of the power grid. The synchronous generators in the power grid are divided into two sets of synchronous generators using the dividing line as the boundary.

[0022] Calculate the rotor inertia center angle of the two synchronous generator sets respectively. By comparing the size of the rotor inertia center angles of the two synchronous generator sets, the synchronous generator with the larger rotor inertia center angle is classified into the leading synchronous generator set, and the synchronous generator with the smaller rotor inertia center angle is classified into the lagging synchronous generator set.

[0023] As a preferred embodiment of the transient power angle stability margin calculation method described in this invention, the transient power angle stability margin includes:

[0024] Calculate the difference in rotor inertia center angle between the leading synchronous generator set and the lagging synchronous generator set corresponding to each time node, obtain the transient power angle stability margin period, and calculate the synchronous generator rotor inertia center frequency within the transient power angle stability margin period.

[0025] Based on the center frequency of the synchronous generator rotor inertia, the transient power angle stability margin corresponding to the transient power angle stability margin period is calculated, and the minimum transient power angle stability margin is taken as the transient power angle stability margin after a grid fault occurs.

[0026] As a preferred embodiment of the transient power angle stability margin calculation method described in this invention, it further includes:

[0027] Based on the moment of inertia and frequency of the synchronous generator during the transient power angle stability margin period, calculate the center frequency of the synchronous generator rotor inertia during the transient power angle stability margin period.

[0028] Based on the moment of inertia, frequency, and rotor inertia center frequency of the synchronous generator during the transient power angle stability margin period, the transient power angle stability margin corresponding to each transient power angle stability margin period is calculated.

[0029] Secondly, the present invention provides a system for calculating transient power angle stability margin, comprising,

[0030] The dominant active power distribution point acquisition module is used to acquire dynamic response data when the power grid is in operation and to calculate and acquire the dominant active power distribution point based on the dynamic response data when the power grid is in operation and to acquire the dominant active power distribution point.

[0031] The active power balance point acquisition module is used to perform equivalent transformation on the neighboring network of the dominant active power balance point to obtain the location of the power grid active power balance point corresponding to each time node.

[0032] The generator partitioning module is used to partition the synchronous generators in the power grid into a leading synchronous generator set and a lagging synchronous generator set according to the active power balance point of the power grid.

[0033] The stability margin acquisition module is used to obtain the transient power angle stability margin period based on the leading synchronous generator set and the lagging synchronous generator set corresponding to each time node, and to calculate the transient power angle stability margin corresponding to the transient power angle stability margin period.

[0034] Thirdly, the present invention provides a computing device, comprising:

[0035] Memory and processor;

[0036] The memory is used to store computer-executable instructions, and the processor is used to execute the computer-executable instructions. When the computer-executable instructions are executed by the processor, they implement the steps of the transient power angle stability margin calculation method.

[0037] Fourthly, the present invention provides a computer-readable storage medium storing computer-executable instructions that, when executed by a processor, implement the steps of the transient power angle stability margin calculation method.

[0038] Compared with the prior art, the beneficial effects of this invention are as follows: Synchronous generators in the power grid are dynamically grouped according to the specific location of the active power balance point of the power grid at each time node after the disturbance, enabling a qualitative judgment of the impact of synchronous generators on transient power angle stability at each time node; Based on the kinetic energy deviation of the leading and lagging synchronous generators relative to the rotor inertia centers of all synchronous generators, a transient power angle stability margin assessment index for the power system is designed, which aligns with the essential requirement of synchronous operation of all synchronous generators in the power grid, providing a basis for quantitative assessment of the transient power angle stability of the power system under different operating conditions and after different disturbances. Attached Figure Description

[0039] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0040] Figure 1 This is a schematic diagram of the overall process of the transient power angle stability margin calculation method according to an embodiment of the present invention. Detailed Implementation

[0041] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0042] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0043] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0044] This invention is described in detail with reference to the schematic diagrams. When detailing the embodiments of this invention, for ease of explanation, the cross-sectional views illustrating the device structure may be partially enlarged, not adhering to the usual scale. Furthermore, the schematic diagrams are merely examples and should not be construed as limiting the scope of protection of this invention. In actual fabrication, the three-dimensional spatial dimensions of length, width, and depth should be included.

[0045] Furthermore, in the description of this invention, it should be noted that the terms "upper," "lower," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the system or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. In addition, the terms "first," "second," or "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0046] Unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" in this invention should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; similarly, they can refer to mechanical connections, electrical connections, or direct connections, or indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0047] Example 1

[0048] Reference Figure 1 As an embodiment of the present invention, a method for calculating transient power angle stability margin is provided, comprising:

[0049] S100: Acquire dynamic response data when the power grid is in operation and obtain the dominant active power distribution point based on the dynamic response data when the power grid is in operation and obtain the dynamic response data.

[0050] In this embodiment of the application, the dynamic response data during power grid operation faults mainly includes real-time collected power grid operation status parameters, current and voltage waveforms recorded by the fault recorder, action records of protection devices, and simulation data generated by simulation analysis software.

[0051] Specifically, the power grid monitoring system collects real-time operating status parameters of various devices in the power grid, including but not limited to voltage, current, active power, reactive power, frequency, and phase angle. These parameters are continuously monitored during normal grid operation and respond rapidly when a fault occurs, recording key data changes before and after the fault. For specific fault events, more detailed and specialized data are collected; for example, fault recorders are used to accurately record current and voltage waveforms over a period of time before and after the fault. Combining the above data, simulation analysis software is also needed to model and simulate the power grid, simulating the dynamic response process of the power grid after a fault occurs. These simulation analyses can generate a large amount of simulation data, including network equations corresponding to each time point, the internal potential phase angle of synchronous generators, and generator active power output. This data is of great significance for a deeper understanding of the power grid fault mechanism, assessment of power grid stability, and the development of effective control strategies.

[0052] Preferably, the network equations and the phase angle of the internal potential of the synchronous generators are obtained at each time node, the dominant index of each active power distribution point in the power grid at each time node is calculated, the active power distribution point corresponding to the maximum value of the dominant index is defined as the dominant active power distribution point at the current time node, and the two synchronous generator groups corresponding to the dominant index of the dominant active power distribution point are taken as the two dominant synchronous generator groups at the current time node.

[0053] In this embodiment of the application, the network equations include mathematical equations describing the electrical connections between various components in the power grid. These equations are based on circuit theory and electromagnetic field theory and are used to represent the relationship between parameters such as voltage, current, and power of the power grid under different operating conditions.

[0054] The preferred formula for calculating the dominant indicator is:

[0055]

[0056] Among them, L i Let γ be the complete set of active power distribution points at the i-th time node. l.i G is the dominant indicator of the active power distribution point l at the i-th time node. i Let G1 be the complete set of synchronous generators at time point i, and G2 be the two synchronous generator groups corresponding to the dominant index of active power distribution point l at time point i. Let g1 and g2 be the sensitivities of the active power flowing out of active power distribution point l at the i-th time node, respectively. Let g1 and g2 be the internal potential phase angles of the synchronous generators g1 and g2 at the i-th time node, respectively.

[0057] It should be noted that by using dynamic response data, the dominant indicators of each active power point in the power grid at each time node were calculated, and the active power point that has the greatest impact on the dynamic response of the power grid when a fault occurs—the dominant active power point—was obtained. Furthermore, by considering the sensitivity of synchronous generators to the active power flowing out of the active power point and the phase angle of the generator's internal potential, the propagation mechanism of the fault in the power grid was analyzed in depth. By continuously monitoring and analyzing these indicators, power grid planners and operators can discover potential problems in power grid design and operation, thereby optimizing the power grid structure, improving equipment performance, and perfecting protection configuration, fundamentally improving the safety and operating efficiency of the power grid.

[0058] S102: Perform equivalent transformation on the neighboring network of the dominant active power distribution point to obtain the location of the active power balance distribution point of the power grid at each time node;

[0059] Preferably, by performing Y-Δ network equivalent transformation on the neighboring network of the dominant active power distribution point, the transformed power grid includes two sub-networks connected by a T-shaped network consisting of 3 equivalent nodes, 2 equivalent branches and 1 equivalent load branch, and the two synchronous generator dominant groups at the current time node are located in different sub-networks;

[0060] The active power flowing into the equivalent load branch from the two equivalent branches is equal. The electrical distance between the node connected to the equivalent load branch and the dominant active power distribution point is the smallest. The equivalent node connected to the equivalent load branch is taken as the active power balance distribution point.

[0061] Specifically, after a thorough analysis of the dominant active power distribution point, performing an equivalent transformation on its neighboring networks becomes a crucial step. This operation aims to further simplify the power grid model in order to more clearly reveal the active power balance characteristics of the power grid under fault conditions. This invention uses the Y-Δ network equivalent transformation method to transform the complex power grid structure into a T-type network model consisting of two sub-networks, three equivalent nodes, two equivalent branches, and one equivalent load branch. This transformation not only preserves the main electrical characteristics of the original power grid but also makes the analysis process more intuitive and efficient.

[0062] In the transformed power grid model, the two synchronous generator groups are located in different subnets. When a fault occurs, the mutual influence between different generator groups and the flow of active power are obtained in a timely manner. At the same time, based on the transformed network structure, the equivalent nodes connected to the equivalent load branches are determined as active power balance points.

[0063] The selection of this node is based on two key conditions: first, the active power flowing into the equivalent load branch from the two equivalent branches is equal, ensuring a balanced distribution of active power on both sides of the balance point; second, the electrical distance between the node connected to the equivalent load branch and the dominant active power point is minimized, which means that the node is on the critical path of active power transmission in the power grid, and its stability is crucial to the active power balance of the entire power grid.

[0064] It should be noted that this invention makes the analysis process more efficient and accurate; the clear identification of the active power balance points provides an important basis for assessing the active power balance capability of the power grid under fault conditions; the analysis method of this invention helps those in the art to develop more precise power grid dispatching and control strategies to maintain the stable operation of the power grid after a fault occurs and prevent the further expansion and spread of the fault.

[0065] S104: Based on the active power balance points of the power grid, the synchronous generators in the power grid are divided into leading synchronous generator sets and lagging synchronous generator sets.

[0066] Preferably, by backtracking the network equivalent transformation process, the specific location of the active power balance point on the element in the network before the transformation is obtained, and the specific locations of the active power balance point on the element are connected to form the dividing line of the power grid. The synchronous generators in the power grid are divided into two sets of synchronous generators by using the dividing line as the boundary.

[0067] Preferably, the rotor inertia center angles of the two synchronous generator sets are calculated respectively. By comparing the size of the rotor inertia center angles of the two synchronous generator sets, the synchronous generator with the larger rotor inertia center angle is classified into the leading synchronous generator set, and the synchronous generator with the smaller rotor inertia center angle is classified into the lagging synchronous generator set.

[0068] In this embodiment of the application, the specific formula for calculating the central angle of rotor inertia of the synchronous generator is as follows:

[0069]

[0070] Among them, A i B i These are the two sets of synchronous generators corresponding to the i-th time node. A respectively i B i The rotor inertia center angle of the synchronous generator at time node i, M i.a δ i.a M represents the moment of inertia and internal electromotive force phase angle of synchronous generator a at time node i, respectively. i.b δ i.b These are the moment of inertia and internal electromotive force phase angle of synchronous generator b at the i-th time node, respectively.

[0071] Specifically, after determining the dividing line, the generators are divided into two groups; for each of these two groups, the rotor inertia center angle of all generators within it is calculated. The rotor inertia center angle is a parameter that reflects the dynamic characteristics of the generator rotor rotation. It takes into account the generator's inertia and kinetic energy, as well as their deviations from the system's average rotational speed.

[0072] After calculating the rotor inertia center angles for the two sets, these two center angles are compared. If the rotor inertia center angle of the first set is greater than that of the second set, then the generators in the first set change their rotational speed faster than the system as a whole after the fault, that is, their behavior is "leading" the system average response, and this set is named the leading synchronous generator set. Conversely, the set with the smaller rotor inertia center angle has a relatively slower change in generator rotational speed, that is, it is "lagging" the system average response, so it is named the lagging synchronous generator set.

[0073] S106: Based on the leading synchronous generator set and lagging synchronous generator set corresponding to each time node, obtain the transient power angle stability margin period and calculate the transient power angle stability margin corresponding to the transient power angle stability margin period.

[0074] Preferably, the difference between the center angle of rotor inertia of the synchronous generators in the leading synchronous generator set and the lagging synchronous generator set corresponding to each time node is calculated to obtain the transient power angle stability margin period, and the center frequency of rotor inertia of the synchronous generators within the transient power angle stability margin period is calculated.

[0075] The specific process for obtaining the transient power angle stability margin time period is as follows: If the A corresponding to the i-th time node is... iFor a leading synchronous generator set, the relative angle δ between the rotor inertia centers of the leading synchronous generator set and the lagging synchronous generator set corresponding to the i-th time node is calculated. i Set as Otherwise, the relative angle δ between the rotor inertia centers of the leading synchronous generator set and the lagging synchronous generator set corresponding to the i-th time node is calculated. i Set as

[0076] For each time node δ i If the time series data consists of at least one data point greater than the power angle difference setpoint δ used to determine transient power angle instability, then... 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 For I e In the case where there were no extreme points before, I s Set to 1, determining the number of time periods for transient power angle stability margin calculation to be 1, with the start and end numbers corresponding to the time periods being I and I, respectively. s and I e Otherwise, determine the number of time periods for calculating the transient power angle stability margin as the number of extreme points, denoted as n. Sort the extreme points in ascending order of their corresponding serial numbers. Determine the starting and ending serial numbers of the first time period as 1 and the serial number of the first extreme point, respectively. The starting and ending serial numbers of the second time period as the serial numbers of the first and second extreme points, respectively, and so on. The starting and ending serial numbers of the nth time period as the serial numbers of the (n-1)th and nth extreme points, respectively.

[0077] Preferably, the center frequency of the synchronous generator rotor inertia during the transient power angle stability margin period is calculated based on the moment of inertia and frequency of the synchronous generator during the transient power angle stability margin period.

[0078] In this embodiment of the application, the specific formula for calculating the rotor inertia center frequency of the synchronous generator at each time node within the time period is as follows:

[0079]

[0080] Where, ω j.k G is the rotor inertia center frequency of the synchronous generator corresponding to the k-th time node within the j-th time period for calculating transient power angle stability margin. j.k M represents the complete set of synchronous generators in the power grid at the k-th time node within the j-th time period for calculating transient power angle stability margin.j.k.g ω j.k.g These are the moment of inertia and frequency of synchronous generator g at the k-th time node within the j-th time period of the transient power angle stability margin calculation;

[0081] Preferably, based on the center frequency of the synchronous generator rotor inertia, the transient power angle stability margin corresponding to the transient power angle stability margin period is calculated, and the minimum transient power angle stability margin is used as the transient power angle stability margin after a grid fault occurs.

[0082] Preferably, the transient power angle stability margin corresponding to each transient power angle stability margin period is calculated based on the moment of inertia, frequency, and rotor inertia center frequency of the synchronous generator during the transient power angle stability margin period.

[0083] In this embodiment of the application, the specific formula for calculating the transient power angle stability margin corresponding to each time period is as follows:

[0084]

[0085] Where, η j The transient power angle stability margin is calculated for the j-th time period. 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 corresponding to the j-th time period in the transient power angle stability margin calculation, respectively. j.k D j.k M represents the leading and lagging synchronous generator sets corresponding to the k-th time node within the j-th time period of the transient power angle stability margin calculation. j.k.g ω j.k.g These represent the moment of inertia and frequency of the synchronous generator g at the k-th time node within the j-th time period of the transient power angle stability margin calculation, respectively. j.k The rotor inertia center frequency ω of the synchronous generator at the k-th time node within the j-th time period is used to calculate the transient power angle stability margin. r ω is the rated frequency of the synchronous generator. up·g ω dn·g These are the upper and lower limits of the transient frequency safety for the synchronous generator g, respectively.

[0086] It should be noted that this invention, by accurately dividing the leading synchronous generator set and the lagging synchronous generator set, and based on the dynamic characteristics of these sets, effectively identifies and calculates the power angle stability margin period and its corresponding stability margin of the power grid during transient processes. By calculating the change in the relative angle of the rotor inertia center between the leading and lagging generator sets, and combining it with the set power angle difference setting value, the transient power angle stability margin period is determined. After determining the transient power angle stability margin period, the rotor inertia center frequency within the period is calculated. Based on the rotor inertia center frequency, this invention calculates the stability margin corresponding to each transient power angle stability margin period by comprehensively considering the rotational inertia, frequency, and transient frequency safety upper and lower limits of the synchronous generators, and selects the minimum value as the transient power angle stability margin after a power grid fault, thereby improving the accuracy of stability margin calculation and providing an important reference for the safe and stable operation of the power grid.

[0087] The above is a schematic scheme of a transient power angle stability margin calculation method according to this embodiment. It should be noted that the technical solution of the transient power angle stability margin calculation system and the technical solution of the transient power angle stability margin calculation method described above belong to the same concept. For details not described in detail in the technical solution of the transient power angle stability margin calculation system in this embodiment, please refer to the description of the technical solution of the transient power angle stability margin calculation method described above.

[0088] The transient power angle stability margin calculation system in this embodiment includes:

[0089] The dominant active power distribution point acquisition module is used to acquire dynamic response data when the power grid is in operation and to calculate and acquire the dominant active power distribution point based on the dynamic response data when the power grid is in operation and the fault.

[0090] The active power balance point acquisition module is used to perform equivalent transformation on the neighboring network of the dominant active power balance point to obtain the location of the active power balance point of the power grid at each time node.

[0091] The generator partitioning module is used to divide the synchronous generators in the power grid into leading synchronous generator sets and lagging synchronous generator sets according to the active power balance points of the power grid.

[0092] The stability margin acquisition module is used to obtain the transient power angle stability margin period based on the leading synchronous generator set and the lagging synchronous generator set corresponding to each time node, and to calculate the transient power angle stability margin corresponding to the transient power angle stability margin period.

[0093] This embodiment also provides a computing device suitable for calculating transient power angle stability margin, including:

[0094] The system includes a memory and a processor. The memory stores computer-executable instructions, and the processor executes these instructions to implement the transient power angle stability margin calculation method proposed in the above embodiments.

[0095] This embodiment also provides a storage medium storing a computer program that, when executed by a processor, implements the transient power angle stability margin calculation method proposed in the above embodiments.

[0096] The storage medium proposed in this embodiment and the method for calculating transient power angle stability margin proposed in the above embodiments belong to the same inventive concept. Technical details not described in detail in this embodiment can be found in the above embodiments, and this embodiment has the same beneficial effects as the above embodiments.

[0097] Based on the above description of the implementation methods, those skilled in the art can clearly understand that the present invention can be implemented using software and necessary general-purpose hardware, and of course, it can also be implemented using hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as a computer floppy disk, read-only memory (ROM), random access memory (RAM), flash memory, hard disk, or optical disk, etc., including several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods of the various embodiments of the present invention.

[0098] Example 2

[0099] Referring to Table 1, an embodiment of the present invention provides a method for calculating transient power angle stability margin. To verify its beneficial effects, experimental simulation results are provided.

[0100] Electromagnetic transient simulation was performed on a real power grid. The fault was set as Dunha N-2 fault, the fault time was 2s, and the short circuit duration was 0.2s.

[0101] The network equations and phase angles of the synchronous generator's internal potential are obtained at each time point. The dominant indices of each active power distribution point in the power grid at each time point are calculated. In this embodiment, taking time point 2.3s as an example, the calculation results of the dominant indices of the active power distribution point are shown in Table 1.

[0102] Among them, the three nodes and indicators with the largest dominant indicators are as follows: Hexi node is 0.275, Shazhou node is 0.273, and Haixi node is 0.271. The dominant active point is Hexi node.

[0103] Table 1 Calculation Results of Node Dominance Indicators

[0104] Active points dominant indicators Active points dominant indicators Hexi 0.275 Fish Card 0.235 sandbar 0.273 Lanzhou 0.209 Haixi 0.271 Tara 0.168 Wusheng 0.268 Qaidam 0.120 Jiuquan 0.259 smokestacks 0.028

[0105] As shown in Table 1, under the Dunha N-2 fault scenario, the dominant index of the active power distribution point in the power grid after the fault was analyzed by electromagnetic transient simulation. It was determined that the dominant active power distribution point at 0.3 seconds after the fault, i.e. 2.3 seconds, is the Hexi node, and its dominant index is higher than that of other nodes.

[0106] After obtaining the dominant index results, at each time point, an equivalent transformation is performed on the neighboring network of the dominant active power balance point to obtain the transformed active power balance point location of the power grid at each time point.

[0107] By tracing back through the network equivalent transformation process, the specific location of the active power balance point on the element in the network before the transformation can be obtained.

[0108] Taking 2.3s as an example, the specific locations of the active power balance points in the network before the transformation are the Jiuquan node and the Yuka node. Connecting these specific locations serves as the dividing line of the power grid, further dividing the synchronous generators in the power grid into a leading synchronous generator set and a lagging synchronous generator set. The leading synchronous generators include: Xinkesu, Xinsantang, Xinbazhou, etc., while the lagging synchronous generators include: Shaanxi Xinyi, Shaanxi Binchang, Ningyinchuan, etc.

[0109] Based on the leading and lagging synchronous generator sets corresponding to each time node, the transient power angle stability margin period is obtained as 2s to 2.61s. Based on the obtained transient power angle stability margin period, the corresponding transient power angle stability margin is calculated to be 71.6%.

[0110] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for calculating transient power angle stability margin, characterized in that, include: Acquire dynamic response data during power grid operation faults, and calculate and obtain the dominant active power distribution point based on the dynamic response data during power grid operation faults; The dominant active power distribution point neighborhood network is transformed into an equivalent value to obtain the location of the power grid active power balance point at each time node. Based on the active power balance points of the power grid, the synchronous generators in the power grid are divided into leading synchronous generator sets and lagging synchronous generator sets. Based on the leading synchronous generator set and lagging synchronous generator set corresponding to each time node, the transient power angle stability margin period is obtained, and the transient power angle stability margin corresponding to the transient power angle stability margin period is calculated.

2. The transient power angle stability margin calculation method as described in claim 1, characterized in that, Calculating and obtaining the dominant active power distribution point includes, Obtain the network equations and phase angles of the internal potential of the synchronous generators at each time node, calculate the dominant index of each active power distribution point in the power grid at each time node, define the active power distribution point corresponding to the maximum value of the dominant index as the dominant active power distribution point at the current time node, and take the two synchronous generator groups corresponding to the dominant index of the dominant active power distribution point as the two dominant synchronous generator groups at the current time node.

3. The transient power angle stability margin calculation method as described in claim 2, characterized in that, The formula for calculating the dominant indicator is: Among them, L i Let γ be the complete set of active power distribution points at the i-th time node. l.i G is the dominant indicator of the active power distribution point l at the i-th time node. i Let G1 be the complete set of synchronous generators at time point i, and G2 be the two synchronous generator groups corresponding to the dominant index of active power distribution point l at time point i. Let g1 and g2 be the sensitivities of the active power flowing out of active power distribution point l at the i-th time node, respectively. These are the internal potential phase angles of synchronous generator g1 and synchronous generator g2 at the i-th time node, respectively.

4. The method for calculating transient power angle stability margin as described in claim 1 or 2, characterized in that, The equivalent transformation of the dominant active power distribution point neighborhood network includes: By performing Y-Δ network equivalent transformation on the neighboring network of the dominant active power distribution point, the transformed power grid includes two sub-networks connected by a T-shaped network consisting of 3 equivalent nodes, 2 equivalent branches and 1 equivalent load branch, and the two synchronous generator dominant groups at the current time node are located in different sub-networks; The active power flowing into the equivalent load branch from the two equivalent branches is equal, and the electrical distance between the node connected to the equivalent load branch and the dominant active power distribution point is the smallest. The equivalent node connected to the equivalent load branch is taken as the active power balancing distribution point.

5. The transient power angle stability margin calculation method as described in claim 4, characterized in that, The synchronous generators in the power grid are divided into leading synchronous generator sets and lagging synchronous generator sets, including... Based on the backtracking of the network equivalent transformation process, the specific location of the active power balance point on the element in the network before the transformation is obtained. The specific locations of the active power balance point on the element are connected to form the dividing line of the power grid. The synchronous generators in the power grid are divided into two sets of synchronous generators using the dividing line as the boundary. Calculate the rotor inertia center angle of the two synchronous generator sets respectively. By comparing the size of the rotor inertia center angles of the two synchronous generator sets, the synchronous generator with the larger rotor inertia center angle is classified into the leading synchronous generator set, and the synchronous generator with the smaller rotor inertia center angle is classified into the lagging synchronous generator set.

6. The transient power angle stability margin calculation method as described in claim 5, characterized in that, Transient work angle stability margin includes, Calculate the difference in rotor inertia center angle between the leading synchronous generator set and the lagging synchronous generator set corresponding to each time node, obtain the transient power angle stability margin period, and calculate the synchronous generator rotor inertia center frequency within the transient power angle stability margin period. Based on the center frequency of the synchronous generator rotor inertia, the transient power angle stability margin corresponding to the transient power angle stability margin period is calculated, and the minimum transient power angle stability margin is taken as the transient power angle stability margin after a grid fault occurs.

7. The transient power angle stability margin calculation method as described in claim 6, characterized in that, It also includes, Based on the moment of inertia and frequency of the synchronous generator during the transient power angle stability margin period, calculate the center frequency of the synchronous generator rotor inertia during the transient power angle stability margin period. Based on the moment of inertia, frequency, and rotor inertia center frequency of the synchronous generator during the transient power angle stability margin period, the transient power angle stability margin corresponding to each transient power angle stability margin period is calculated.

8. A system for calculating transient power angle stability margin, characterized in that, include, The dominant active power distribution point acquisition module is used to acquire dynamic response data when the power grid is in operation and to calculate and acquire the dominant active power distribution point based on the dynamic response data when the power grid is in operation and to acquire the dominant active power distribution point. The active power balance point acquisition module is used to perform equivalent transformation on the neighboring network of the dominant active power balance point to obtain the location of the power grid active power balance point corresponding to each time node. The generator partitioning module is used to partition the synchronous generators in the power grid into a leading synchronous generator set and a lagging synchronous generator set according to the active power balance point of the power grid. The stability margin acquisition module is used to obtain the transient power angle stability margin period based on the leading synchronous generator set and the lagging synchronous generator set corresponding to each time node, and to calculate the transient power angle stability margin corresponding to the transient power angle stability margin period.

9. An electronic device, comprising: Memory and processor; The memory is used to store computer-executable instructions, and the processor is used to execute the computer-executable instructions. When the computer-executable instructions are executed by the processor, they implement the steps of the transient power angle stability margin calculation method according to any one of claims 1 to 7.

10. A computer-readable storage medium storing computer-executable instructions that, when executed by a processor, implement the steps of the transient power angle stability margin calculation method according to any one of claims 1 to 7.

Images