Power system frequency security domain calculation method and device and electronic equipment

Abstract

The invention discloses a power system frequency security domain calculation method, which comprises the following steps: analyzing influence factors of system frequency security by using a system frequency response model, determining an operation space of a frequency security domain based on the influence factors, performing time domain simulation in the operation space by combining actual transient parameters of a whole network, and searching boundary points meeting frequency security conditions. And the simulated boundary points are fitted to draw the system frequency security domain, and the boundary of the security domain is defined according to the system frequency security evaluation index when the operation space is defined, so that the frequency security of the system can be analyzed according to the operation mode of the power system.

Description

Technical Field

[0001] The present invention relates to power grid frequency security analysis technology, and in particular to a method, device and electronic equipment for calculating the frequency security domain of a power system. Background Art

[0002] With the widespread access to new energy (such as wind power, solar energy, etc.), the structure of the power system has changed significantly, and the system frequency regulation capability faces huge challenges. Traditional power systems are mainly based on synchronous generators, which have large inertia and help stabilize the frequency of the power grid. However, with the increase in the penetration rate of new energy, traditional synchronous machines are gradually replaced by new energy. Since wind and solar power generation devices have almost no inertia, the change in the power structure of the system leads to a decrease in the system inertia, which reduces the system frequency support capacity. When the power grid is disturbed, the frequency is more likely to fluctuate, the frequency changes faster, and the difficulty of frequency regulation increases.

[0003] Secondly, the unpredictability and intermittency of renewable energy generation (such as solar power generation depends on sunshine, wind power generation depends on wind power) make frequency regulation more difficult. With the shutdown of synchronous machines, traditional frequency regulation resources are reduced, and renewable energy usually does not have the ability to regulate frequency, or its ability to participate in frequency regulation is weak, so the frequency regulation burden of new power systems is increased.

[0004] In addition, the introduction of renewable energy reduces the system inertia, and the insufficient system inertia response may lead to a large rate of change of frequency (RoCoF) in the system. The large fluctuations in renewable energy power generation increase the demand for secondary frequency regulation in the system. Traditional units are unable to respond quickly, which may trigger RoCoF protection action, causing system equipment to go offline, further deteriorating the system frequency, and the system faces the risk of large-scale load shedding and machine shedding.

[0005] Therefore, it is necessary to study the frequency stability of the power grid system under a high proportion of renewable energy penetration to ensure the frequency stability of the power system. Summary of the invention

[0006] Based on this, the present invention aims to propose a method, device and electronic equipment for calculating the frequency security domain of an electric power system, which can reflect the frequency security of the system through the calculation of the frequency security domain.

[0007] In a first aspect, the present invention provides a method for calculating a frequency security domain of a power system, wherein the output structure of the power system includes new energy sources, and the method comprises:

[0008] Construct a frequency response model of the system and use it to determine the factors affecting the frequency stability of the system;

[0009] Determine the operating space of the frequency security domain based on influencing factors, and define the boundaries of the frequency security domain based on the power system frequency security assessment indicators;

[0010] Based on the defined boundaries, time domain simulation is performed in the operating space combined with the actual transient parameters of the entire network to search for boundary points that meet the frequency safety conditions, and the frequency safety domain of the system is drawn by curve fitting of the boundary points.

[0011] Furthermore, the operating space of the frequency safety domain is determined according to the frequency response model, including:

[0012] Taking the influencing factors as the spatial dimensions of the operating space, a multi-dimensional operating space of the frequency safety domain is established, and the multi-dimensional operating space includes more than three dimensions;

[0013] Reduce the multi-dimensional operating space to a three-dimensional operating space.

[0014] Furthermore, the multi-dimensional operation space includes five dimensions: FLC reserve, primary frequency regulation reserve, total kinetic energy of system synchronous machine, system disturbance and load. The multi-dimensional operation space is reduced to a three-dimensional operation space, including:

[0015] The two dimensions of system disturbance and load are simplified and eliminated. Based on the extreme operation scenarios of the system, the system maximum active power imbalance and the annual minimum load level are used as boundary conditions for calculation. The five-dimensional safety domain is simplified to a three-dimensional operation space constructed by the three dimensions of FLC reserve, primary frequency regulation reserve, and total kinetic energy of the system synchronous machine. The FLC reserve dimension is divided into several discrete sections, and a two-dimensional frequency safety domain coordinate system is established on each section with the primary frequency regulation reserve as the horizontal coordinate and the total kinetic energy of the system synchronous machine as the vertical coordinate.

[0016] Furthermore, based on the defined boundaries, time domain simulation is performed in the operating space in combination with the actual transient parameters of the entire network to search for boundary points that meet the frequency safety conditions, including:

[0017] For each slice of the FLC alternate dimension, perform the following process:

[0018] Adjust the total kinetic energy of the system synchronous machine, the output of new energy and the startup mode, perform time domain simulation by changing the total kinetic energy and primary frequency modulation of the system, and record the coordinate points that meet the system frequency safety assessment index in the frequency safety domain coordinate system, and the coordinate points constitute the boundary of the frequency safety domain;

[0019] The frequency safety region of the system is drawn by curve fitting for the coordinate points.

[0020] Furthermore, the safety boundary of the frequency safety domain is defined according to the system frequency safety assessment index, including:

[0021] In the frequency safety domain coordinate system, the system maximum frequency change rate is used to define the lower boundary of the frequency safety domain, the maximum frequency deviation is used to define the curve boundary of the frequency safety domain, and the quasi-steady-state frequency deviation is used to define the left boundary of the frequency safety domain. The frequency safety domain is the upper right space surrounded by the lower boundary, the curve boundary and the left boundary.

[0022] Furthermore, the total kinetic energy of the system synchronous machine, the output of new energy and the startup mode are adjusted. By changing the total kinetic energy of the system and the primary frequency modulation, time domain simulation is performed. The coordinate points that meet the system frequency safety assessment indicators are recorded in the frequency safety domain coordinate system, including:

[0023] The minimum system synchronous machine total kinetic energy under the frequency change rate safety constraint is calculated according to the system maximum frequency change rate. On the basis of satisfying the minimum system synchronous machine total kinetic energy, the first operation mode point that just satisfies the maximum frequency deviation is searched through time domain simulation, and the coordinate point corresponding to the first operation mode point is used as the starting point of the boundary.

[0024] The primary frequency modulation of the system is changed with a fixed step size, and the total kinetic energy of the system synchronous machine is increased. The second operating mode point that meets the maximum frequency deviation requirement is searched through time domain simulation until the system frequency peak and recovery frequency just meet the system frequency safety requirements, and the corresponding coordinate point is recorded as the end point of the boundary.

[0025] Further, the curve fitting includes Lagrange interpolation method.

[0026] In a second aspect, the present invention provides a power system frequency security domain calculation device, comprising:

[0027] A frequency response model building module is used to build a frequency response model of the system and use the frequency response model to determine the factors affecting the frequency stability of the system;

[0028] An operation space determination module is used to determine the operation space of the frequency security domain based on influencing factors and define the boundary of the frequency security domain according to the power system frequency security assessment index;

[0029] The simulation and fitting module is used to perform time domain simulation based on the defined boundaries in the operating space combined with the actual transient parameters of the entire network, search for boundary points that meet the frequency safety conditions, and draw the frequency safety domain of the system by curve fitting of the boundary points.

[0030] In a third aspect, the present invention provides an electronic device comprising a memory storing computer executable instructions and a processor, wherein when the computer executable instructions are executed by the processor, the device executes each step of the method for calculating the frequency security domain of a power system provided in the first aspect.

[0031] In a fourth aspect, the present invention provides a readable storage medium storing a computer executable program, which, when executed, can implement the various steps of the method for calculating the frequency security domain of a power system provided in the first aspect.

[0032] It can be seen from the above technical solutions that the present invention has the following beneficial effects:

[0033] The present invention provides a method for calculating the frequency safety domain of an electric power system. The method uses a system frequency response model to analyze influencing factors of the system frequency safety, determines the operating space of the frequency safety domain based on the influencing factors, performs time domain simulation in the operating space in combination with actual transient parameters of the entire network, searches for boundary points that meet frequency safety conditions, and draws the system frequency safety domain by fitting the simulated boundary points. When defining the operating space, the boundary of the safety domain is defined according to the system frequency safety evaluation index, which is conducive to analyzing the frequency safety of the system according to the operating mode of the electric power system. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0035] Figure 1 A flowchart of a method for calculating a frequency security region of a power system provided by an embodiment of the present invention;

[0036] Figure 2 A flowchart of a method for calculating a frequency security region of a power system provided by another embodiment of the present invention;

[0037] Figure 3 A frequency response curve diagram of a power system provided by an embodiment of the present invention;

[0038] Figure 4 A schematic diagram of system frequency safety domain simulation and boundary curve fitting provided by an embodiment of the present invention;

[0039] Figure 5 A structural diagram of a power system frequency security domain calculation device provided by an embodiment of the present invention;

[0040] Figure 6 This is a diagram of the electronic device architecture provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0041] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] At present, there have been studies on the thermal stability safety domain, voltage safety domain, inertia safety domain, frequency band oscillation safety domain, etc. of power systems, but there are fewer studies on the characterization of frequency safety domain, especially for power grid structures with a high proportion of renewable energy penetration. The main purpose of calculating the frequency safety domain is to determine whether the system frequency can be maintained within the allowable range when various disturbances occur in the power system (such as generator failure, load fluctuation, etc.) to prevent the system frequency from being too high or too low, thereby causing equipment damage or system collapse. System frequency stability is particularly important for renewable energy power systems.

[0043] In addition to being affected by system inertia, system frequency stability is also affected by primary frequency regulation and standby. At the same time, under asynchronous grid partitioning, the DC frequency limit control (FLC) capacity adjustment will also significantly affect the frequency change after a fault.

[0044] Based on the above, the present invention provides a method, device and electronic device for calculating the frequency security domain of a power system through the following embodiments, which reflects the frequency security of the system through the calculation of the frequency security domain.

[0045] See also Figure 1 An embodiment of the present invention provides a method for calculating a frequency security region of a power system, comprising the following steps:

[0046] Step S110: construct a frequency response model of the system, and use the frequency response model to determine factors affecting the frequency stability of the system.

[0047] In this step, by analyzing the frequency stability excitation mechanism of the power system, especially the power system with a high proportion of new energy, the frequency response model of the system is constructed to analyze the key factors affecting the frequency security of the system. The frequency response model usually includes the inertial response of the generator set, the primary frequency regulation response, the secondary frequency regulation response, the frequency response of the load, and the system regulator and controller.

[0048] Step S120. Determine the operating space of the frequency security domain based on the influencing factors, and define the boundary of the frequency security domain according to the power system frequency security assessment index.

[0049] The frequency safety domain refers to the set of all possible states in which the system frequency can be maintained within the allowable range when facing various possible disturbances (such as load changes and generator failures). It is used to characterize the safe area in which the power system can maintain stable operation under frequency disturbances. Based on the frequency response model, the operating space in which the system can operate stably under different disturbance conditions can be determined, and the frequency safety domain can be further drawn on this basis.

[0050] Specifically, the influencing factors of frequency safety are determined according to the frequency response model, and the influencing factors are used to construct a multi-dimensional operating space of the frequency safety domain. For practical application and simplified analysis, the multi-dimensional operating space can be reduced in dimension. In this embodiment, the dimension is reduced to a three-dimensional operating space.

[0051] In a further embodiment, the three-dimensional operating space of the present invention is represented by three dimensions: FLC reserve, primary frequency modulation reserve and total kinetic energy of the system synchronous machine. Specifically, the dimension of FLC reserve is divided into a number of discrete sections, and a frequency safety domain coordinate system is established on each section with the primary frequency modulation reserve as the horizontal coordinate and the total kinetic energy of the system synchronous machine as the vertical coordinate, that is, the three-dimensional operating space is further decomposed into the curved boundaries of several two-dimensional planes.

[0052] Step S130. Based on the defined boundaries, time domain simulation is performed in the operating space in combination with the actual transient parameters of the entire network, boundary points that meet the frequency safety conditions are searched, and the frequency safety domain of the system is drawn by curve fitting of the boundary points.

[0053] Specifically, the boundary of the safety domain is a key factor in constituting the safety domain. To draw the safety domain, its boundary and its definition must be clarified first. In a further embodiment, the present invention uses five dimensions to characterize the operating space of system frequency safety. The five dimensions include FLC standby, primary frequency modulation standby, total kinetic energy of system synchronous machine, system disturbance and load. On this basis, step S130 specifically includes the following steps:

[0054] For each slice of the FLC alternate dimension, perform the following process:

[0055] Adjust the total kinetic energy of the system synchronous machine, the output of new energy and the startup mode, perform time domain simulation by changing the total kinetic energy and primary frequency modulation of the system, and record the coordinate points that meet the system frequency safety assessment index in the frequency safety domain coordinate system, and the coordinate points constitute the boundary of the frequency safety domain;

[0056] The frequency safety region of the system is drawn by curve fitting for the coordinate points.

[0057] In a further embodiment, for the several two-dimensional planes divided as mentioned above, the above-mentioned frequency safety domain drawing process can be executed for each two-dimensional plane, and their union can be obtained in actual application, or the frequency safety domain corresponding to each FLC spare slice can be input separately.

[0058] In a further embodiment, in the frequency safety domain coordinate system, the system's maximum frequency change rate is used to define the lower boundary of the frequency safety domain, the maximum frequency deviation is used to define the curve boundary of the frequency safety domain, and the quasi-steady-state frequency deviation is used to define the left boundary of the frequency safety domain. The frequency safety domain is the upper right space surrounded by the lower boundary, the curve boundary and the left boundary.

[0059] In a further embodiment, the process of recording coordinate points in the frequency safety domain coordinate system in the time domain simulation includes:

[0060] The minimum system synchronous machine total kinetic energy under the frequency change rate safety constraint is calculated according to the system maximum frequency change rate. On the basis of satisfying the minimum system synchronous machine total kinetic energy, the first operation mode point that just satisfies the maximum frequency deviation is searched through time domain simulation, and the coordinate point corresponding to the first operation mode point is used as the starting point of the boundary.

[0061] The primary frequency modulation of the system is changed with a fixed step size, and the total kinetic energy of the system synchronous machine is increased. The second operating mode point that meets the maximum frequency deviation requirement is searched through time domain simulation until the system frequency peak and recovery frequency just meet the system frequency safety requirements, and the corresponding coordinate point is recorded as the end point of the boundary.

[0062] In order to further illustrate the frequency safety domain calculation method provided by the present invention, Figure 2~Figure 4 This will be further introduced.

[0063] See also Figure 2~Figure 4 An embodiment of the present invention provides a method for calculating a frequency security domain of a power system, including system frequency response model construction, security domain boundary definition, and time domain simulation.

[0064] According to the inertia center theory, the rotor swing equation of the synchronous generator in the aggregation system can be used to obtain the equivalent rotor swing equation of the system, and then the expression of the power system frequency response process under active power disturbance is obtained as follows:

[0065] (1)

[0066] in, represents the change of the system input mechanical power, Represents the change of the system output electromagnetic power, Indicates the change of system frequency. When the system power is balanced, the input mechanical power is equal to the electromagnetic power, and the system frequency remains stable. When a fault occurs, the system electromagnetic power changes, generating unbalanced power, causing the system frequency to change. The active power of the load changes with the change of frequency, which is manifested as the frequency response of the load. At the same time, when the system frequency changes beyond the DC frequency load control (FLC) dead zone, the electromagnetic power is also affected by the DC FLC. The following expression for the change of system electromagnetic power after a fault can be obtained, assuming that the per-unit value of the disturbance power is :

[0067] (2)

[0068] Where D is the frequency regulation effect coefficient of the load; assuming that the DC FLC response has no dead zone and only considers the proportional control link, the response of the DC FLC based on the frequency difference is also simplified to express.

[0069] The mechanical power change after the disturbance is provided by the synchronous machine speed regulator. The low-order model of the primary frequency modulation response of the speed regulator is adopted, and the time constant speed of the synchronous generator speed regulator of the system aggregation is considered. The expression of the mechanical power change of the system input after the disturbance is:

[0070] (3)

[0071] in, is the aggregation coefficient of the system speed regulator, Synchronous machine high pressure turbine coefficient aggregation parameters, is the time constant of the synchronous generator governor, It is the aggregation parameter of the speed governor adjustment coefficient of the synchronous unit.

[0072] Substituting the above equations (2) and (3) into equation (1), the frequency analytical expression of the power system can be obtained through Laplace transformation:

[0073] (4)

[0074] According to the above formula (4), the frequency response model of the system is constructed as follows: Figure 3 As shown in the figure, from the constructed model, it can be determined that the factor affecting the system frequency security is mainly the DC FLC regulation capability. , primary frequency modulation ( , , ), system disturbance , System inertia and load frequency regulation capability .

[0075] On this basis, the system frequency safety domain can be approximated as a regional operating space in a five-dimensional space. In order to facilitate practical application and simplify analysis, the frequency safety domain needs to be reduced in dimension. In this embodiment, the two dimensions of system disturbance and load frequency regulation capability are reduced, that is, the maximum active power imbalance to be balanced by system frequency regulation is , and considering the minimum load level Frequency safety domain calculation is carried out under the operating mode.

[0076] Through the above-mentioned dimensionality reduction process, the frequency safety domain of the present embodiment is reduced to an operating space represented by three dimensions: FLC reserve, primary frequency modulation reserve and total kinetic energy of the system synchronous machine. Since FLC reserve is a dimension that can be directly and accurately observed and controlled, N sections can be further selected on the FLC reserve dimension to decompose the two-dimensional safety domain boundary in the three-dimensional space into N two-dimensional planes represented by two dimensions: primary frequency modulation reserve and total kinetic energy of the system synchronous machine.

[0077] Specifically, a frequency safety domain coordinate system is established on each slice with the primary frequency regulation reserve as the horizontal coordinate and the total kinetic energy of the system synchronous machine as the vertical coordinate, and the coordinate points that meet the system frequency safety operation requirements are recorded in this coordinate system.

[0078] Figure 3 The frequency response curve of the power system is shown. Figure 3 It can be seen that there are three indicators to describe the frequency stability of the system: maximum frequency change rate ( ), maximum frequency deviation and quasi-steady-state frequency deviation. The significance of the maximum frequency change rate and the maximum frequency deviation is to avoid the action of the three lines of defense of the system, namely primary frequency regulation, secondary frequency regulation and load shedding, and the significance of the quasi-steady-state frequency deviation is to meet the system recovery frequency requirements.

[0079] (1) Frequency safety domain boundary defined by the maximum frequency change rate

[0080] The maximum frequency change rate of the system is expressed as follows:

[0081] (5)

[0082] The variables in formula (5) are all per-unit values. After converting them into nominal values, formula (6) is expressed as:

[0083] (6)

[0084] From the above formula (6), it can be seen that the maximum frequency change rate depends only on the disturbance Total kinetic energy of the synchronous machine , considering the maximum active power imbalance as Under this condition, the maximum frequency change rate is inversely proportional to the total kinetic energy of the system synchronous machine. Considering the requirements of system equipment protection and three lines of defense, the maximum frequency change rate of the system can be comprehensively proposed. According to formula (6), we have:

[0085] (7)

[0086] Then the frequency safety domain boundary defined by the maximum frequency change rate is:

[0087] (8)

[0088] (2) Frequency safety domain boundary defined by quasi-steady-state frequency deviation

[0089] According to the above formula (5), the final value theorem can be obtained:

[0090] (9)

[0091] Combined with the above formula (8), since the system load frequency modulation D is a constant, considering the minimum load level Under the quasi-steady-state frequency deviation, the system is related to the DC FLC capability and the system primary frequency regulation capability. The safety margin under the quasi-steady-state frequency deviation indicator is defined as the FLC standby and primary frequency regulation standby operating points that just meet the system recovery frequency.

[0092] (3) Frequency safety domain boundary defined by maximum frequency deviation

[0093] Based on the above formula (5), the maximum frequency change rate is affected by multiple factors such as DC FLC regulation capability, primary frequency regulation, disturbance, system inertia and load frequency regulation capability. Therefore, the safety margin defined by the maximum frequency deviation is defined as the operating mode that just meets the system's maximum frequency requirement and minimum frequency requirement.

[0094] Based on the frequency response model constructed above and the defined safety boundary, the frequency safety domain calculation process of the system specifically includes the following steps:

[0095] Step S210: Determine the starting point of the security domain boundary.

[0096] Specifically, the system operation mode is adjusted, the penetration rate of new energy is adjusted, and conventional units are shut down to adjust the total kinetic energy of the system synchronous machine to the minimum total kinetic energy of the system synchronous machine under the RoCoF constraint calculated by equation (8). Under this operation mode, the primary frequency regulation standby of each unit is adjusted, and the maximum active power imbalance considered during the fault is , perform time domain simulation in the coordinate system defined above, search for the operating mode point that just meets the maximum frequency deviation requirement, and determine its corresponding coordinate point as the initial point of the safety domain boundary.

[0097] Step S220: Simulate frequency safety domain boundary points.

[0098] Specifically, with a given step size Change the system operation mode and adjust the startup mode synchronously, increase the total kinetic energy of the system synchronous machine, find the operation mode point that just meets the maximum frequency deviation requirements, record the corresponding total kinetic energy of the synchronous machine and the system primary frequency modulation backup data under the current operation mode, until the system frequency peak and recovery frequency just meet the system frequency safety requirements, and use this operation mode point as the last point of the safety domain boundary.

[0099] Step S230: Perform curve fitting on the simulated discrete coordinate points to draw the frequency safety domain.

[0100] Specifically, for the coordinate points obtained by simulation in steps S210 to S220, the curve boundary of the frequency safety region is obtained by curve fitting using the Lagrange interpolation method. The fitting process is expressed as follows:

[0101] (10)

[0102] The FLC standby is changed and the above S210 to S230 are repeated to calculate the system frequency safety domain under different FLC standby conditions.

[0103] It is understandable that curve fitting is not limited to the interpolation method given in this embodiment, and a suitable interpolation method can be selected according to the selected step size, such as Newton interpolation method, spline interpolation method, piecewise linear interpolation method, etc.

[0104] Figure 4 : represents a simulation and curve fitting schematic diagram given in this embodiment, in which the dotted line parallel to the abscissa corresponds to the minimum system synchronous machine total kinetic energy satisfying the RoCoF constraint, which represents the boundary defined by the maximum frequency change rate, Figure 4 The coordinate point where the green curve in the figure intersects with it is the starting point of the simulation. After that, the simulation searches for the operating mode point that just meets the maximum frequency deviation requirement. The red dot in the coordinate system indicates the point obtained during the simulation that does not meet the definition of the safety domain boundary. The dotted line parallel to the ordinate corresponds to the system recovery frequency requirement. The coordinate point where the green curve in the figure intersects with it is the end point of the simulation. The final green curve is obtained by curve fitting the green coordinate point, which represents the boundary of the system frequency safety domain. The green curve and the area to the right jointly depicted by the two dotted lines represent the frequency safety domain of the system.

[0105] The above disclosed embodiment describes in detail a method for calculating the frequency security domain of a power system. The above disclosed method can be implemented using various forms of equipment. Therefore, the present invention also discloses a device for calculating the frequency security domain of a power system corresponding to the above method. A specific embodiment is given below for detailed description.

[0106] See also Figure 5 An embodiment of the present invention provides a power system frequency security domain calculation device, comprising:

[0107] A frequency response model building module 502 is used to build a frequency response model of the system and determine the factors affecting the frequency stability of the system using the frequency response model;

[0108] An operation space determination module 504 is used to determine the operation space of the frequency security domain based on the influencing factors, and define the boundary of the frequency security domain according to the power system frequency security assessment index;

[0109] The simulation and fitting module 506 is used to perform time domain simulation in the operating space based on the defined boundaries and in combination with the actual transient parameters of the entire network, search for boundary points that meet the frequency safety conditions, and draw the frequency safety domain of the system by curve fitting of the boundary points.

[0110] The implementation principle and technical effects of the device provided in the embodiments of the present application are the same as those of the aforementioned method embodiments. For the sake of brief description, for matters not mentioned in the device embodiment, reference may be made to the corresponding contents in the aforementioned method embodiments.

[0111] The following embodiments are described by taking the method applied to a computer device as an example. It can be understood that the computer device can be any device with computing and processing functions, and can be but not limited to a server or a personal laptop computer, etc. In one embodiment, the computer device can be an application server, and the application server can be a server for running an application to be tested.

[0112] See also Figure 6 , which shows a hardware block diagram of an electronic device, the electronic device is intended to represent various forms of digital computers, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device can also represent various forms of mobile devices, such as personal digital processing, cellular phones, smart phones, wearable devices, and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely examples and are not intended to limit the implementation of the present application described and / or required herein.

[0113] like Figure 6 As shown, the electronic device includes: at least one processor 1, at least one communication interface 2, at least one memory 3 and at least one communication bus 4;

[0114] In the embodiment of the present application, the number of the processor 1, the communication interface 2, the memory 3, and the communication bus 4 is at least one, and the processor 1, the communication interface 2, and the memory 3 communicate with each other through the communication bus 4;

[0115] The processor 1 may be a central processing unit CPU, or an application-specific integrated circuit ASIC (Application Specific Integrated Circuit), or one or more integrated circuits configured to implement the embodiments of the present invention, etc.;

[0116] The memory 3 may include a high-speed RAM memory, and may also include a non-volatile memory, such as at least one disk memory;

[0117] The memory stores a program, and the processor can call the program stored in the memory, and the program is used to: implement each processing flow of the aforementioned power system frequency security domain calculation solution.

[0118] An embodiment of the present invention also provides a readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the various processing flows of the power system frequency security domain calculation scheme provided in the above embodiment and / or any possible implementation method in combination with the embodiment are implemented.

[0119] The above-mentioned embodiments have described the present invention in particular detail with respect to possible scenarios, and those skilled in the art will recognize that the present invention can be practiced through other embodiments. The specific naming of components, the capitalization of terms, attributes, data structures, or any other programming or structural aspects are not mandatory or important, and the mechanisms or features of the present invention may have different names, forms, or procedures. The system may be implemented by a combination of hardware and software (as described), entirely by hardware elements, or entirely by software elements. The specific division of functions between the various system components described herein is exemplary only and not mandatory; on the contrary, the functions performed by a single system component may be performed by multiple components, or the functions performed by multiple components may be performed by a single component.

[0120] Those skilled in the art should understand that the various steps of the above disclosed method can be implemented by a general computing device, they can be concentrated on a single computing device, or distributed on a network composed of multiple computing devices, optionally, they can be implemented with program codes executable by the computing device, so that they can be stored in a storage device and executed by the computing device, or they can be made into individual integrated circuit modules, or multiple modules or steps therein can be made into a single integrated circuit module for implementation. Thus, the embodiments of the present invention are not limited to any specific combination of hardware and software.

[0121] These computing device executable programs (also referred to as programs, software, software applications, or code) include machine instructions for programmable processors, and these computing programs can be implemented using high-level procedural and / or object-oriented programming languages, and / or assembly / machine languages. As used herein, the terms "machine-readable medium" and "computer-readable medium" refer to any computer program product, device, and / or device (e.g., disk, optical disk, memory, programmable logic device (PLD)) for providing machine instructions and / or data to a programmable processor, including a machine-readable medium that receives machine instructions as a machine-readable signal. The term "machine-readable signal" refers to any signal for providing machine instructions and / or data to a programmable processor.

[0122] Certain aspects of the present invention include process steps and instructions described herein in the form of algorithms. It should be noted that the process steps and instructions of the present invention can be implemented in software, firmware and / or hardware, and when implemented by software, it can be downloaded, stored on different platforms used by various operating systems and operated from the platforms.

[0123] Those skilled in the art will understand that the structures shown in the accompanying drawings are merely block diagrams of partial structures related to the scheme of the present application, and do not constitute a limitation on the terminal device to which the scheme of the present application is applied. The specific terminal device may include more or fewer components than shown in the figures, or combine certain components, or have a different arrangement of components.

[0124] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "possible design" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0125] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for calculating the frequency security region of a power system, characterized in that: The output structure of the power system includes new energy sources, and the method includes: Constructing a frequency response model of the system, and using the frequency response model to determine factors affecting the frequency stability of the system; Determine the operating space of the frequency security domain based on the influencing factors, and define the boundary of the frequency security domain according to the power system frequency security assessment index; Based on the defined boundary, time domain simulation is performed in the operating space in combination with actual transient parameters of the entire network to search for boundary points that meet frequency safety conditions, and the frequency safety domain of the system is drawn by curve fitting of the boundary points.

2. The method according to claim 1, characterized in that The determining of the operating space of the frequency safety domain based on the influencing factors includes: Taking the influencing factors as the spatial dimensions of the operating space, a multi-dimensional operating space of the frequency safety domain is established, wherein the multi-dimensional operating space includes more than three dimensions; The multi-dimensional operating space is reduced to a three-dimensional operating space.

3. The method according to claim 2, characterized in that The multi-dimensional operation space includes five dimensions, namely, FLC standby, primary frequency regulation standby, total kinetic energy of system synchronous machine, system disturbance and load. The multi-dimensional operation space is reduced to a three-dimensional operation space, including: The two dimensions of system disturbance and load are simplified and eliminated. Based on the extreme operation scenarios of the system, the system maximum active power imbalance and the annual minimum load level are used as boundary conditions for calculation. The five-dimensional safety domain is simplified to a three-dimensional operation space constructed by the three dimensions of FLC reserve, primary frequency regulation reserve, and total kinetic energy of the system synchronous machine. The FLC reserve dimension is divided into several discrete sections, and a two-dimensional frequency safety domain coordinate system is established on each section with the primary frequency regulation reserve as the horizontal coordinate and the total kinetic energy of the system synchronous machine as the vertical coordinate.

4. The method according to claim 3, characterized in that The step of performing time domain simulation in the operation space based on the defined boundary in combination with actual transient parameters of the entire network to search for boundary points that meet frequency safety conditions includes: For each slice of the FLC alternate dimension, perform the following process: Adjust the total kinetic energy of the system synchronous machine, the output of new energy and the startup mode, perform time domain simulation by changing the total kinetic energy and primary frequency modulation of the system, record the information about the primary frequency modulation standby and the total kinetic energy of the synchronous machine that meets the data of the power system frequency security assessment index mode under the time domain simulation in the frequency security domain coordinate system, and record the coordinate points of the security domain boundary on the two-dimensional security domain, and the coordinate points constitute the boundary of the frequency security domain; The frequency safety domain is constructed by curve fitting the coordinate points and drawing the frequency safety domain boundary of the system.

5. The method according to claim 4, characterized in that Defining the boundary of the frequency security domain according to the power system frequency security assessment index includes: In the frequency safety domain coordinate system, the system maximum frequency change rate is used to define the lower boundary of the frequency safety domain, the maximum frequency deviation is used to define the curve boundary of the frequency safety domain, and the quasi-steady-state frequency deviation is used to define the left boundary of the frequency safety domain. The frequency safety domain is the upper right space surrounded by the lower boundary, the curve boundary and the left boundary.

6. The method according to claim 4, characterized in that The total kinetic energy of the synchronous machine, the output of new energy and the startup mode of the system are adjusted, and the time domain simulation is performed by changing the total kinetic energy and primary frequency modulation of the system. The coordinate points that meet the system frequency safety assessment index are recorded in the frequency safety domain coordinate system, including: The minimum system synchronous machine total kinetic energy under the frequency change rate safety constraint is calculated according to the system maximum frequency change rate, and on the basis of satisfying the minimum system synchronous machine total kinetic energy, a first operation mode point that just satisfies the maximum frequency deviation is searched through time domain simulation, and the coordinate point corresponding to the first operation mode point is used as the starting point of the boundary; The primary frequency modulation of the system is changed with a fixed step size, and the total kinetic energy of the system synchronous machine is increased. The second operating mode point that meets the maximum frequency deviation requirement is searched through time domain simulation until the system frequency peak and the recovery frequency just meet the system frequency safety requirements, and the corresponding coordinate point is recorded as the end point of the boundary.

7. The method according to claim 1, characterized in that The curve fitting includes Lagrange interpolation method.

8. A device for calculating frequency security region of a power system, characterized in that: The output structure of the power system includes new energy sources, and the device includes: A frequency response model building module is used to build a frequency response model of the system and use the frequency response model to determine factors affecting the frequency stability of the system; An operation space determination module, used to determine the operation space of the frequency security domain based on the influencing factors, and define the boundary of the frequency security domain according to the power system frequency security assessment index; The simulation and fitting module is used to perform time domain simulation in the operating space based on the defined boundary and the actual transient parameters of the entire network, search for boundary points that meet the frequency safety conditions, and draw the frequency safety domain of the system by curve fitting of the boundary points.

9. An electronic device, characterized in that: The device comprises a memory storing computer executable instructions and a processor. When the computer executable instructions are executed by the processor, the device executes the method for calculating the frequency security domain of a power system as described in any one of claims 1 to 7.

10. A readable storage medium, characterized in that: A computer executable program is stored, and when the program is executed, the method for calculating the frequency security domain of a power system as described in any one of claims 1 to 7 can be implemented.

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