Method and device for determining lowest point of frequency of power system, equipment and storage medium

Abstract

The invention relates to a power system frequency lowest point determination method and device, equipment and a storage medium. The method comprises the following steps: based on each order frequency coefficient of a generator speed regulator in a power system under power step disturbance, a virtual frequency modulation coefficient of a new energy unit, each order frequency coefficient of a load and a frequency coefficient of direct current frequency limit control FLC modulation, performing frequency modulation on the basis of the virtual frequency modulation coefficient of the new energy unit; determining an initial frequency maximum deviation point of the power system and an initial time lowest point corresponding to the initial frequency maximum deviation point; and correcting the initial frequency maximum deviation point and the initial time lowest point to obtain a target frequency maximum deviation point corresponding to the initial frequency maximum deviation point and a target time lowest point corresponding to the target frequency maximum deviation point. The method can accurately determine the lowest frequency point of the power system.

Description

Technical Field

[0001] The present application relates to the technical field of power system frequency stability analysis and control, and in particular to a method, device, equipment and storage medium for determining the lowest frequency point of a power system. Background Art

[0002] With the large-scale grid connection of clean and low-carbon energy such as wind power and photovoltaics and ultra-high voltage direct current, the power system with synchronous machines as the main body has gradually evolved into a power system with new energy as the main body, showing an increasingly obvious low inertia trend. The system frequency response capability is weakened after active disturbance, and frequency stability faces severe challenges.

[0003] In order to accurately evaluate and control the frequency of the power system, it is necessary to know the lowest point of the frequency, that is, the maximum frequency deviation and the time of the lowest frequency point. Most of the existing frequency prediction methods use time domain simulation method, simplified model method and data driven method, but these frequency prediction methods have problems such as low prediction accuracy and lack of interpretability of prediction results. Summary of the invention

[0004] Based on this, it is necessary to provide a method, device, equipment and storage medium for determining the lowest frequency point of an electric power system in response to the above-mentioned technical problems, which can accurately determine the lowest frequency point of the electric power system.

[0005] In a first aspect, the present application provides a method for determining a minimum frequency point of a power system, the method comprising:

[0006] Based on the various order frequency coefficients of the generator speed governor under power step disturbance, the virtual frequency modulation coefficient of the new energy unit, the various order frequency coefficients of the load and the frequency coefficient of the DC frequency limit control FLC modulation in the power system, the initial frequency maximum deviation point of the power system and the initial time minimum point corresponding to the initial frequency maximum deviation point are determined; wherein, the various order frequency coefficients of the generator speed governor under power step disturbance include the zero-order frequency coefficient of the engine and the second-order frequency coefficient of the engine, and the various order frequency coefficients of the load include the zero-order frequency coefficient of the load and the first-order frequency coefficient of the load;

[0007] The initial frequency maximum deviation point and the initial time minimum point are corrected to obtain the target frequency maximum deviation point corresponding to the initial frequency maximum deviation point and the target time minimum point corresponding to the target frequency maximum deviation point.

[0008] In one embodiment, based on the frequency coefficients of each order of the generator speed regulator under the power step disturbance, the virtual frequency modulation coefficient of the new energy unit, the frequency coefficients of each order of the load and the frequency coefficient of the DC frequency limit control FLC modulation in the power system, the initial frequency maximum deviation point of the power system and the initial time minimum point corresponding to the initial frequency maximum deviation point are determined, including:

[0009] Based on the frequency coefficients of each order of the generator speed regulator under the power step disturbance in the power system, the virtual frequency regulation coefficient of the new energy unit, the frequency coefficient of each order of the load, the frequency coefficient of the DC, the system equivalent damping constant and the active disturbance suffered by the system, the first frequency coefficient and the maximum deviation point of the initial frequency are determined; based on the product of the first frequency coefficient and the maximum deviation point of the initial frequency, the initial time minimum point corresponding to the maximum deviation point of the initial frequency is determined.

[0010] In one embodiment, based on frequency coefficients of various orders of the generator speed regulator under power step disturbance, virtual frequency regulation coefficients of new energy units, frequency coefficients of various orders of loads, frequency coefficients of direct current, system equivalent damping constant and active disturbance suffered by the system, determining the first frequency coefficient and the maximum deviation point of the initial frequency includes:

[0011] Based on the virtual frequency regulation coefficient of the new energy units in the power system, the various order frequency coefficients of the load, the frequency coefficient of the direct current and the system equivalent damping constant, the first intermediate coefficient is determined; the ratio of the second order frequency coefficient of the engine and the first intermediate coefficient is determined as the first frequency coefficient; based on the first intermediate coefficient, the zero order frequency coefficient of the load, the zero order frequency coefficient of the engine and the active disturbance suffered by the system, the maximum deviation point of the initial frequency is determined.

[0012] In one embodiment, determining the maximum deviation point of the initial frequency based on the first intermediate coefficient, the load zero-order frequency coefficient, the engine zero-order frequency coefficient and the active disturbance amount suffered by the system includes:

[0013] The result of adding the load zero-order frequency coefficient and the engine zero-order frequency coefficient minus the active disturbance suffered by the system is used to obtain the second intermediate coefficient; the ratio of the second intermediate coefficient to the first intermediate coefficient is determined as the maximum deviation point of the initial frequency.

[0014] In one of the embodiments, it includes: fitting the power-frequency response curve of the generator speed governor based on the historical frequency and historical power of the power system to obtain the frequency coefficients of each order of the generator speed governor under the power step disturbance; obtaining the virtual frequency coefficient of the new energy unit based on the frequency regulation characteristics of the new energy unit; obtaining the frequency coefficients of each order of the load based on the frequency regulation characteristics of the load; and obtaining the frequency coefficient of the DC FLC modulation based on the frequency regulation characteristics of the DC FLC modulation.

[0015] In one embodiment, the initial frequency maximum deviation point and the initial time minimum point are corrected to obtain the target frequency maximum deviation point corresponding to the initial frequency maximum deviation point and the target time minimum point corresponding to the target frequency maximum deviation point, including:

[0016] The initial frequency maximum deviation point and the initial time minimum point are input into a pre-trained back propagation neural network BPNN model to correct the initial frequency maximum deviation point and the initial time minimum point, so as to obtain the target frequency maximum deviation point corresponding to the initial frequency maximum deviation point and the target time minimum point corresponding to the target frequency maximum deviation point; wherein the BPNN model is trained based on the historical operation data of the power system; the historical operation data includes frequency, power, time, power shortage, frequency minimum point, system equivalent inertia constant, system equivalent damping constant and generator speed regulator parameters.

[0017] In a second aspect, the present application further provides a device for determining the lowest frequency point of a power system, the device comprising:

[0018] An initial determination module is used to determine the initial frequency maximum deviation point of the power system and the initial time minimum point corresponding to the initial frequency maximum deviation point based on the various order frequency coefficients of the generator speed governor under power step disturbance, the virtual frequency modulation coefficient of the new energy unit, the various order frequency coefficients of the load and the frequency coefficient of the DC frequency limit control FLC modulation in the power system; wherein the various order frequency coefficients of the generator speed governor under power step disturbance include the zero-order frequency coefficient of the engine and the second-order frequency coefficient of the engine, and the various order frequency coefficients of the load include the zero-order frequency coefficient of the load and the first-order frequency coefficient of the load;

[0019] The correction module is used to correct the initial frequency maximum deviation point and the initial time minimum point to obtain the target frequency maximum deviation point corresponding to the initial frequency maximum deviation point and the target time minimum point corresponding to the target frequency maximum deviation point.

[0020] In a third aspect, the present application further provides a computer device, including a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the following steps are implemented:

[0021] Based on the various order frequency coefficients of the generator speed governor under power step disturbance, the virtual frequency modulation coefficient of the new energy unit, the various order frequency coefficients of the load and the frequency coefficient of the DC frequency limit control FLC modulation in the power system, the initial frequency maximum deviation point of the power system and the initial time minimum point corresponding to the initial frequency maximum deviation point are determined; wherein, the various order frequency coefficients of the generator speed governor under power step disturbance include the zero-order frequency coefficient of the engine and the second-order frequency coefficient of the engine, and the various order frequency coefficients of the load include the zero-order frequency coefficient of the load and the first-order frequency coefficient of the load;

[0022] The initial frequency maximum deviation point and the initial time minimum point are corrected to obtain the target frequency maximum deviation point corresponding to the initial frequency maximum deviation point and the target time minimum point corresponding to the target frequency maximum deviation point.

[0023] In a fourth aspect, the present application further provides a computer-readable storage medium having a computer program stored thereon, wherein when the computer program is executed by a processor, the following steps are implemented:

[0024] Based on the various order frequency coefficients of the generator speed governor under power step disturbance, the virtual frequency modulation coefficient of the new energy unit, the various order frequency coefficients of the load and the frequency coefficient of the DC frequency limit control FLC modulation in the power system, the initial frequency maximum deviation point of the power system and the initial time minimum point corresponding to the initial frequency maximum deviation point are determined; wherein, the various order frequency coefficients of the generator speed governor under power step disturbance include the zero-order frequency coefficient of the engine and the second-order frequency coefficient of the engine, and the various order frequency coefficients of the load include the zero-order frequency coefficient of the load and the first-order frequency coefficient of the load;

[0025] The initial frequency maximum deviation point and the initial time minimum point are corrected to obtain the target frequency maximum deviation point corresponding to the initial frequency maximum deviation point and the target time minimum point corresponding to the target frequency maximum deviation point.

[0026] In a fifth aspect, the present application further provides a computer program product, including a computer program, which implements the following steps when executed by a processor:

[0027] Based on the various order frequency coefficients of the generator speed governor under power step disturbance, the virtual frequency modulation coefficient of the new energy unit, the various order frequency coefficients of the load and the frequency coefficient of the DC frequency limit control FLC modulation in the power system, the initial frequency maximum deviation point of the power system and the initial time minimum point corresponding to the initial frequency maximum deviation point are determined; wherein, the various order frequency coefficients of the generator speed governor under power step disturbance include the zero-order frequency coefficient of the engine and the second-order frequency coefficient of the engine, and the various order frequency coefficients of the load include the zero-order frequency coefficient of the load and the first-order frequency coefficient of the load;

[0028] The initial frequency maximum deviation point and the initial time minimum point are corrected to obtain the target frequency maximum deviation point corresponding to the initial frequency maximum deviation point and the target time minimum point corresponding to the target frequency maximum deviation point.

[0029] The above-mentioned method, device, equipment, storage medium and program product for determining the lowest frequency point of the power system obtains the various order frequency coefficients of the generator speed regulator under power step disturbance, the virtual frequency modulation coefficient of the new energy unit, the various order frequency coefficients of the load and the frequency coefficient of the DC frequency limit control FLC modulation in the power system; then, it can be analyzed and calculated based on the various order frequency coefficients of the generator speed regulator under power step disturbance, the virtual frequency modulation coefficient of the new energy unit, the various order frequency coefficients of the load and the frequency coefficient of the DC frequency limit control FLC modulation, so as to determine the initial frequency maximum deviation point of the power system and the initial time lowest point corresponding to the initial frequency maximum deviation point; further, the initial frequency maximum deviation point and the initial time lowest point corresponding to the initial frequency maximum deviation point are corrected to obtain more accurate target frequency maximum deviation point and target time lowest point. This scheme takes into account the power-frequency characteristics of various heterogeneous resources in the power system, that is, obtains the frequency coefficients of each order of the generator speed regulator under the power step disturbance, the virtual frequency modulation coefficient of the new energy unit, the frequency coefficients of each order of the load and the frequency coefficient of the DC frequency limit control FLC modulation, so as to achieve a comprehensive consideration of the power system; further, the calculated initial frequency maximum deviation point and initial time minimum point are further corrected, so that the final determined target frequency maximum deviation point and target time minimum point are more accurate, thereby achieving the accurate determination of the lowest frequency point of the power system. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the related technologies, the drawings required for use in the embodiments or the related technical descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0031] FIG1 is an application environment diagram of a method for determining the lowest frequency point of a power system provided in an embodiment of the present application;

[0032] FIG2 is a schematic flow chart of a method for determining the lowest frequency point of a power system provided in an embodiment of the present application;

[0033] FIG3 is a schematic diagram of a process for determining the maximum deviation point of the initial frequency and the minimum point of the initial time provided in an embodiment of the present application;

[0034] FIG4 is a schematic diagram of a process for determining a first frequency coefficient and a maximum deviation point of an initial frequency provided in an embodiment of the present application;

[0035] FIG5 is a flow chart of another method for determining the lowest frequency point of a power system provided in an embodiment of the present application;

[0036] FIG6 is a structural block diagram of a device for determining the lowest frequency point of a power system provided in an embodiment of the present application;

[0037] FIG7 is a structural block diagram of another device for determining the lowest frequency point of a power system provided in an embodiment of the present application;

[0038] FIG8 is a diagram of the internal structure of a computer device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0040] The method for determining the lowest frequency point of the power system provided in the embodiment of the present application can be applied to the application environment shown in FIG1. ​​Among them, the terminal 102 communicates with the server 104 through the network. The data storage system can store the data that the server 104 needs to process. The data storage system can be integrated on the server 104, or it can be placed on the cloud or other network servers. The server 104 calculates the initial frequency maximum deviation point of the power system and the initial time minimum point corresponding to the initial frequency maximum deviation point based on the frequency coefficients of the generator speed regulator under the power step disturbance, the virtual frequency modulation coefficient of the new energy unit, the frequency coefficients of the load, and the frequency coefficient of the DC frequency limit control FLC modulation, and corrects the calculated initial frequency maximum deviation point and initial time minimum point, so as to obtain a more accurate target frequency maximum deviation point and target time minimum point, and the target frequency maximum deviation point and target time minimum point are displayed through the terminal 102. Among them, the terminal 102 can be, but is not limited to, various personal computers, laptops, smart phones, tablet computers, Internet of Things devices and portable wearable devices, and the Internet of Things devices can be smart speakers, smart TVs, smart air conditioners, smart car-mounted devices, etc. The portable wearable device may be a smart watch, a smart bracelet, a head-mounted device, etc. The server 104 may be implemented as an independent server or a server cluster consisting of multiple servers.

[0041] In an exemplary embodiment, as shown in FIG2 , a method for determining the lowest frequency point of a power system is provided. The method is described by taking the application of the method to the server 104 in FIG1 as an example, and the method may include the following steps:

[0042] S201, based on the frequency coefficients of each order of the generator speed regulator under the power step disturbance, the virtual frequency modulation coefficient of the new energy unit, the frequency coefficients of each order of the load and the frequency coefficient of the DC frequency limit control FLC modulation in the power system, determine the initial frequency maximum deviation point of the power system and the initial time minimum point corresponding to the initial frequency maximum deviation point.

[0043] Among them, the various order frequency coefficients of the generator speed governor under the power step disturbance may include but are not limited to the engine zero-order frequency coefficient and the engine second-order frequency coefficient; the virtual frequency regulation coefficient of the new energy unit may include but is not limited to the equivalent droop coefficient of the new energy; the various order frequency coefficients of the load may include but are not limited to the load zero-order frequency coefficient and the load first-order frequency coefficient; the frequency coefficient of the frequency limit control FLC modulation may include but is not limited to the frequency-related gain coefficient.

[0044] Optionally, the initial frequency maximum deviation point and the initial time minimum point are the maximum frequency deviation point and the time minimum point corresponding to the maximum frequency deviation point calculated considering the dynamic process of system frequency response in the power system with multiple heterogeneous resources. Among them, the dynamic process of system frequency response in the power system with multiple heterogeneous resources can be represented by data such as the active output of each resource participating in the primary frequency regulation, the active disturbance suffered by the system, the system equivalent inertia constant, the system equivalent damping constant, and the frequency deviation. Optionally, the active output of each resource participating in the primary frequency regulation can be determined by the speed regulator of the synchronous generator, the frequency control strategy of new energy, the DC FLC modulation characteristics and the frequency characteristics of the load.

[0045] Exemplarily, the frequency coefficients of each order of the generator speed regulator under the power step disturbance, the virtual frequency modulation coefficient of the new energy unit, the frequency coefficients of each order of the load and the frequency coefficient of the DC FLC (frequency limit control, FLC) frequency limit control modulation can be input into the frequency minimum point model; then, the frequency minimum point calculation formula in the frequency minimum point model can be combined to determine the initial frequency maximum deviation point of the power system and the initial time minimum point corresponding to the initial frequency maximum deviation point.

[0046] S202, correcting the initial frequency maximum deviation point and the initial time minimum point to obtain the target frequency maximum deviation point corresponding to the initial frequency maximum deviation point and the target time minimum point corresponding to the target frequency maximum deviation point.

[0047] Among them, the target frequency maximum deviation point can represent the predicted value of the system frequency maximum deviation point when the power system is disturbed; the target time minimum point can represent the predicted value of the system frequency at the time point when the target frequency maximum deviation point is reached.

[0048] Exemplarily, the initial frequency maximum deviation point and the initial time minimum point can be analyzed and corrected by the minimum point correction model, and the target frequency maximum deviation point and the target time minimum point corresponding to the target frequency maximum deviation point can be obtained.

[0049] The above-mentioned method for determining the lowest frequency point of the power system obtains the various order frequency coefficients of the generator speed regulator under the power step disturbance, the virtual frequency regulation coefficient of the new energy unit, the various order frequency coefficients of the load and the frequency coefficient of the DC frequency limit control FLC modulation in the power system; then, it can be analyzed and calculated based on the various order frequency coefficients of the generator speed regulator under the power step disturbance, the virtual frequency regulation coefficient of the new energy unit, the various order frequency coefficients of the load and the frequency coefficient of the DC frequency limit control FLC modulation, so as to determine the initial frequency maximum deviation point of the power system and the initial time lowest point corresponding to the initial frequency maximum deviation point; further, the initial frequency maximum deviation point and the initial time lowest point corresponding to the initial frequency maximum deviation point are corrected to obtain a more accurate target frequency maximum deviation point and target time lowest point. This scheme takes into account the power-frequency characteristics of various heterogeneous resources in the power system, that is, obtains the frequency coefficients of each order of the generator speed regulator under the power step disturbance, the virtual frequency modulation coefficient of the new energy unit, the frequency coefficients of each order of the load and the frequency coefficient of the DC frequency limit control FLC modulation, so as to achieve a comprehensive consideration of the power system; further, the calculated initial frequency maximum deviation point and initial time minimum point are further corrected, so that the final determined target frequency maximum deviation point and target time minimum point are more accurate, thereby achieving the accurate determination of the lowest frequency point of the power system.

[0050] Based on the above embodiment, the embodiment of the present application explains the above embodiment S201 in detail. Specifically, the process of determining the maximum deviation point of the initial frequency and the minimum point of the initial time in the embodiment of the present application, as shown in FIG3, specifically includes the following steps:

[0051] S301, based on the frequency coefficients of various orders of the generator speed regulator under power step disturbance in the power system, the virtual frequency regulation coefficient of the new energy unit, the frequency coefficients of various orders of the load, the frequency coefficient of the DC, the system equivalent damping constant and the active disturbance suffered by the system, determine the first frequency coefficient and the maximum deviation point of the initial frequency.

[0052] It should be noted that the frequency coefficients of each order of the generator speed regulator under power step disturbance, the virtual frequency regulation coefficient of the new energy unit, the frequency coefficients of each order of the load and the frequency coefficient of the DC can all be obtained in advance. The specific acquisition process is as follows.

[0053] (1) Based on the historical frequency and historical power of the power system, the power-frequency response curve of the generator speed governor is fitted to obtain the frequency coefficients of each order of the generator speed governor under power step disturbance.

[0054] For example, the fitted power-frequency response curve can be expressed by a high-order expression, which can be expressed as follows:

[0055] (1)

[0056] in, Indicates the mechanical power deviation output by the system synchronous generator speed regulator; , , and represents the polynomial coefficients related to the rate of change of each order of frequency, represents the zero-order frequency coefficient of the engine, represents the first-order frequency coefficient of the engine, represents the second-order frequency coefficient of the engine, represents the third-order frequency coefficient of the engine, Indicates the frequency deviation of the power system.

[0057] Furthermore, considering the accuracy of fitting and the complexity of calculation, equation (1) can be simplified into a second-order polynomial to describe the active power-frequency characteristics of the generator speed regulator before the frequency minimum point is reached. Optionally, the simplified equation (1) can be expressed as:

[0058] (2)

[0059] (2) Based on the frequency regulation characteristics of the new energy units, the virtual frequency regulation coefficient of the new energy units is obtained.

[0060] It should be noted that most of the current new energy stations participate in the frequency regulation of the power system by implementing virtual synchronization control, virtual inertia control and droop control to achieve frequency response. Among them, the above control schemes are to simulate the frequency response characteristics of the synchronous generator rotor through the control of power electronic inverters and algorithms. The power-frequency characteristics of the new energy unit considering virtual inertia control and droop control can be expressed as:

[0061] (3)

[0062] in, Indicates the power response of the new energy unit actively participating in frequency regulation, represents the equivalent droop coefficient of new energy, Represents the equivalent virtual inertia coefficient.

[0063] (3) Based on the frequency modulation characteristics of the load, the frequency coefficients of each order of the load are obtained.

[0064] It should be noted that when the frequency changes, the active power absorbed by the load from the power system will also change, which is the frequency characteristic of the load. In the dynamic process before the frequency reaches the lowest point after the disturbance, the power-frequency dynamic characteristic of the load can be expressed as:

[0065] (4)

[0066] in, Indicates the system active load power deviation. Indicates the system frequency deviation, and represents the load factor related to each frequency order, represents the load zero-order frequency coefficient, Represents the first-order frequency coefficient of the load.

[0067] (4) Based on the frequency modulation characteristics of DC FLC modulation, the frequency coefficient of DC FLC modulation is obtained.

[0068] It should be noted that for power systems with a high proportion of renewable energy, the frequency characteristics can be improved by suppressing the change of the electromagnetic power of the generator through the fast controllable function of DC power and reducing the deviation between it and the mechanical power. A DC frequency limiter can be used to respond to the frequency deviation of the power system. , automatically modulates the DC power. When the DC modulation reserve power is sufficient, its power-frequency dynamic characteristics can be expressed as:

[0069] (5)

[0070] in, Indicates the power deviation of the system DC modulator, is the frequency dependent gain coefficient.

[0071] Furthermore, it is reasonable to determine the first frequency coefficient and the maximum deviation point of the initial frequency by using the frequency coefficients of each order of the generator speed regulator under power step disturbance in the power system, the virtual frequency regulation coefficient of the new energy unit, the frequency coefficient of each order of the load, the frequency coefficient of DC, the system equivalent damping constant and the active disturbance suffered by the system. The specific reasons are as follows.

[0072] The dynamic process of the system frequency response of the power system with multiple heterogeneous resources can be represented by the active output of each resource participating in the primary frequency regulation, the active disturbance suffered by the system, the system equivalent inertia constant, the system equivalent damping constant, and the frequency deviation. The specific representation is as follows:

[0073] (6)

[0074] in, represents the system equivalent inertia constant, represents the system equivalent damping constant, represents the frequency deviation over time, Indicates the active disturbance suffered by the system, It indicates the active output of each resource (synchronous engine, new energy, DC and load) participating in primary frequency regulation.

[0075] Furthermore, each resource participates in the active power output of primary frequency regulation. It can be expressed by the power-frequency dynamic characteristic expressions of each synchronous engine, new energy, DC and load, namely, equation (2) to equation (5). Specifically, it can be expressed as:

[0076] (7)

[0077] in, Indicates the maximum value of frequency deviation in the power system.

[0078] Rearranging formula (7), we get:

[0079] (8)

[0080] in, .

[0081] Furthermore, formula (8) can be simplified to:

[0082] (9)

[0083] in, , , .

[0084] Furthermore, at the lowest frequency point in the power system, hour, To get the maximum value; Based on formula (9), according to the properties of quadratic functions, we know hour, , the maximum deviation point of the initial frequency is c, that is, . Where a is the first frequency coefficient.

[0085] Exemplarily, the frequency coefficients of each order of the generator speed regulator under the power step disturbance, the virtual frequency regulation coefficient of the new energy unit, the frequency coefficients of each order of the load, the frequency coefficient of the DC, the system equivalent damping constant and the active disturbance suffered by the system can be input into the coefficient calculation model, and the coefficient calculation model calculates the first frequency coefficient a and the initial frequency maximum deviation point c. Among them, the coefficient calculation model has been pre-set with a coefficient calculation formula for calculating the first frequency coefficient and the initial frequency maximum deviation point.

[0086] S302: Determine the initial time lowest point corresponding to the initial frequency maximum deviation point based on the product of the first frequency coefficient and the initial frequency maximum deviation point.

[0087] Exemplarily, the product of the first frequency coefficient a and the initial frequency maximum deviation point c can be determined as the third intermediate coefficient; then, the inverse of the third intermediate coefficient is determined as the fourth intermediate coefficient; based on the square root of the fourth intermediate coefficient, the initial time minimum point t corresponding to the initial frequency maximum deviation point is determined. 0 Optional, the initial time minimum point t 0 The determination process can be expressed as:

[0088] (10)

[0089] It should be noted that formula (10) is based on evidence. First, further analysis of formula (9) yields:

[0090] (11)

[0091] Furthermore, by integrating both sides of equation (11), we can obtain:

[0092] (12)

[0093] when When the initial frequency maximum deviation point corresponds to the initial time minimum point t, 0 , which can be specifically expressed as:

[0094] (13)

[0095] In an embodiment of the present application, by first determining the first frequency coefficient and the maximum deviation point of the initial frequency, the initial time lowest point can be determined based on the first frequency coefficient and the maximum deviation point of the initial frequency, thereby realizing the gradual determination of the lowest frequency point of the power system.

[0096] Based on the above embodiment, the embodiment of the present application explains the above embodiment S301 in detail. Specifically, the process of determining the first frequency coefficient and the maximum deviation point of the initial frequency in the embodiment of the present application, as shown in FIG4, specifically includes the following steps:

[0097] S401, determining a first intermediate coefficient based on a virtual frequency modulation coefficient of a new energy unit in the power system, frequency coefficients of each order of the load, a frequency coefficient of DC FLC modulation, and a system equivalent damping constant.

[0098] For example, the equivalent droop coefficient K in the virtual frequency regulation coefficient of the new energy unit can be used. d , the first-order frequency coefficient of the load among the various order frequency coefficients of the load , frequency-dependent gain coefficient in the frequency coefficient of DC FLC modulation and the system equivalent damping constant D sys , determine the first intermediate coefficient R1. Optionally, the process of determining the first intermediate coefficient R can be expressed as:

[0099] (14)

[0100] S402: Determine the ratio of the second-order frequency coefficient of the engine to the first intermediate coefficient as the first frequency coefficient.

[0101] For example, the second-order frequency coefficient of the generator speed regulator under the power step disturbance can be The ratio of the first intermediate coefficient R1 to the first frequency coefficient a is determined as the first frequency coefficient a. Optionally, the determination process of the first frequency coefficient a can be expressed as:

[0102] (15)

[0103] S403, determining the maximum deviation point of the initial frequency based on the first intermediate coefficient, the load zero-order frequency coefficient, the engine zero-order frequency coefficient and the active power disturbance suffered by the system.

[0104] One possible implementation method is to subtract the active disturbance suffered by the system from the result of adding the load zero-order frequency coefficient and the engine zero-order frequency coefficient to obtain a second intermediate coefficient; and determine the ratio of the second intermediate coefficient to the first intermediate coefficient as the maximum deviation point of the initial frequency.

[0105] For example, the load zero-order frequency coefficient of each order frequency coefficient of the load can be The zero-order frequency coefficient of the engine and the generator speed governor under power step disturbance Add them together and compare the result of the addition with the active disturbance P suffered by the system dSubtract from each other to obtain the second intermediate coefficient R2. Optionally, the determination process of the second intermediate coefficient R2 can be expressed as:

[0106] (16)

[0107] Further, the ratio of the second intermediate coefficient R2 to the first intermediate coefficient R1 is determined as the initial frequency maximum deviation point c. Optionally, the determination process of the second intermediate coefficient R2 can be expressed as:

[0108] (17)

[0109] Another possible implementation method is to input the first intermediate coefficient, the load zero-order frequency coefficient, the engine zero-order frequency coefficient and the active disturbance suffered by the system into the frequency minimum point model, and the frequency minimum point model calculates or predicts the frequency minimum point.

[0110] In an embodiment of the present application, the first intermediate coefficient is determined by calculating the virtual frequency modulation coefficient of the new energy unit in the power system, the various order frequency coefficients of the load, the frequency coefficient of the DC FLC modulation and the system equivalent damping constant; then, the first intermediate coefficient and the second order frequency coefficient of the engine are combined to determine the first frequency coefficient, and the first intermediate coefficient, the zero order frequency coefficient of the load, the zero order frequency coefficient of the engine and the active disturbance suffered by the system are combined to finally determine the maximum deviation point of the initial frequency, that is, through step-by-step analysis, the accurate calculation of the first frequency coefficient and the maximum deviation point of the initial frequency is finally achieved.

[0111] On the basis of the above-mentioned embodiment, the embodiment of the present application explains the above-mentioned embodiment S202 in detail. Specifically, the embodiment of the present application involves obtaining the target frequency maximum deviation point and the target time minimum point, which specifically includes: inputting the initial frequency maximum deviation point and the initial time minimum point into a pre-trained back propagation neural network BPNN model to correct the initial frequency maximum deviation point and the initial time minimum point, and obtaining the target frequency maximum deviation point corresponding to the initial frequency maximum deviation point, and the target time minimum point corresponding to the target frequency maximum deviation point.

[0112] Among them, the BPNN model is trained based on the historical operation data of the power system; the historical operation data include frequency, power, time, power shortage, lowest frequency point (including maximum frequency deviation, lowest time point corresponding to maximum frequency deviation), system equivalent inertia constant, system equivalent damping constant and generator speed regulator parameters.

[0113] It should be noted that the training data (i.e., historical operation data) of the BPNN model can be obtained from the historical operation data of the power system or the simulation data of the power system. The training data may include, but are not limited to, the physical parameters of the frequency regulation unit, the power shortage, and the actual frequency minimum point (the actual frequency maximum deviation point and the actual time minimum point corresponding to the actual frequency maximum deviation point). The initial frequency maximum deviation point and the initial time minimum point corresponding to the initial frequency maximum deviation point are used as the input features of the BPNN model, and the actual frequency maximum deviation point and the actual time minimum point corresponding to the actual frequency maximum deviation point are used as the output features of the BPNN model; the input features and output features of the BPNN model are then normalized and fed into the BPNN model for training, and finally a trained BPNN model is obtained.

[0114] In the embodiment of the present application, by introducing the BPNN model, data features can be filtered, effectively reducing the dependence of BPNN on sample data, realizing the correction of the initial frequency maximum deviation point and the initial time minimum point, and further ensuring the prediction accuracy of the power system frequency minimum point.

[0115] Based on the above embodiment, this embodiment provides an optional example of a method for determining the lowest frequency point of a power system. As shown in FIG5 , the specific implementation process is as follows:

[0116] S501, determining a first intermediate coefficient based on a virtual frequency regulation coefficient of a new energy generating unit in the power system, frequency coefficients of each order of the load, a frequency coefficient of direct current, and a system equivalent damping constant.

[0117] Among them, the various order frequency coefficients of the load include the zero-order frequency coefficient of the load and the first-order frequency coefficient of the load.

[0118] S502: Determine the ratio of the second-order frequency coefficient of the engine to the first intermediate coefficient as the first frequency coefficient.

[0119] The second-order frequency coefficient of the engine is the second-order frequency coefficient of the generator speed regulator under power step disturbance. Optionally, each order frequency coefficient of the generator speed regulator under power step disturbance also includes the zero-order frequency coefficient of the engine.

[0120] Optionally, the power-frequency response curve of the generator speed governor can be fitted based on the historical frequency and historical power of the power system to obtain the frequency coefficients of each order of the generator speed governor under the power step disturbance; based on the frequency regulation characteristics of the new energy unit, the virtual frequency regulation coefficient of the new energy unit can be obtained; based on the frequency regulation characteristics of the load, the frequency coefficients of each order of the load can be obtained; based on the frequency regulation characteristics of the DC FLC modulation, the frequency coefficient of the DC FLC modulation can be obtained.

[0121] S503, subtract the active disturbance amount suffered by the system from the result of adding the load zero-order frequency coefficient and the engine zero-order frequency coefficient to obtain a second intermediate coefficient.

[0122] S504: Determine the ratio of the second intermediate coefficient to the first intermediate coefficient as the initial frequency maximum deviation point.

[0123] S505: Determine the initial time lowest point corresponding to the initial frequency maximum deviation point based on the product of the first frequency coefficient and the initial frequency maximum deviation point.

[0124] S506, input the initial frequency maximum deviation point and the initial time minimum point into a pre-trained back propagation neural network BPNN model to correct the initial frequency maximum deviation point and the initial time minimum point, and obtain the target frequency maximum deviation point corresponding to the initial frequency maximum deviation point, and the target time minimum point corresponding to the target frequency maximum deviation point.

[0125] The BPNN model is trained based on the historical operation data of the power system; the historical operation data include frequency, power, time, power shortage, lowest frequency point, system equivalent inertia constant, system equivalent damping constant and generator speed regulator parameters.

[0126] The specific process of S501-S506 can refer to the description of the above method embodiment, and its implementation principle and technical effect are similar, which will not be repeated here.

[0127] It should be understood that, although the various steps in the flowcharts involved in the above-mentioned embodiments are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps does not have a strict order restriction, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above-mentioned embodiments can include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

[0128] Based on the same inventive concept, the embodiment of the present application also provides a device for determining the lowest point of the power system frequency for implementing the method for determining the lowest point of the power system frequency involved above. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme recorded in the above method, so the specific limitations in one or more embodiments of the device for determining the lowest point of the power system frequency provided below can refer to the limitations of the method for determining the lowest point of the power system frequency above, and will not be repeated here.

[0129] In an exemplary embodiment, as shown in FIG6 , a device 1 for determining the lowest frequency point of a power system is provided, comprising: an initial determination module 10 and a correction module 20, wherein:

[0130] The initial determination module 10 is used to determine the initial frequency maximum deviation point of the power system and the initial time minimum point corresponding to the initial frequency maximum deviation point based on the various order frequency coefficients of the generator speed regulator under power step disturbance, the virtual frequency modulation coefficient of the new energy unit, the various order frequency coefficients of the load and the frequency coefficient of the DC frequency limit control FLC modulation in the power system; wherein, the various order frequency coefficients of the generator speed regulator under power step disturbance include the engine zero-order frequency coefficient and the engine second-order frequency coefficient, and the various order frequency coefficients of the load include the load zero-order frequency coefficient and the load first-order frequency coefficient.

[0131] The correction module 20 is used to correct the initial frequency maximum deviation point and the initial time minimum point to obtain the target frequency maximum deviation point corresponding to the initial frequency maximum deviation point and the target time minimum point corresponding to the target frequency maximum deviation point.

[0132] In one embodiment, as shown in FIG. 7 , the initial determination module 10 specifically further includes:

[0133] The first determination unit 11 is used to determine the first frequency coefficient and the maximum deviation point of the initial frequency based on the frequency coefficients of each order of the generator speed regulator under the power step disturbance, the virtual frequency regulation coefficient of the new energy unit, the frequency coefficients of each order of the load, the frequency coefficient of the DC, the system equivalent damping constant and the active disturbance suffered by the system.

[0134] The second determining unit 12 is used to determine the initial time lowest point corresponding to the initial frequency maximum deviation point based on the product of the first frequency coefficient and the initial frequency maximum deviation point.

[0135] In one embodiment, the first determining unit 11 is further configured to:

[0136] Based on the virtual frequency regulation coefficient of the new energy units in the power system, the various order frequency coefficients of the load, the frequency coefficient of the direct current and the system equivalent damping constant, the first intermediate coefficient is determined; the ratio of the second order frequency coefficient of the engine and the first intermediate coefficient is determined as the first frequency coefficient; based on the first intermediate coefficient, the zero order frequency coefficient of the load, the zero order frequency coefficient of the engine and the active disturbance suffered by the system, the maximum deviation point of the initial frequency is determined.

[0137] In one embodiment, the first determining unit 11 is further configured to:

[0138] The result of adding the load zero-order frequency coefficient and the engine zero-order frequency coefficient minus the active disturbance suffered by the system is used to obtain the second intermediate coefficient; the ratio of the second intermediate coefficient to the first intermediate coefficient is determined as the maximum deviation point of the initial frequency.

[0139] In one embodiment, the power system frequency minimum point determination device 1 further includes:

[0140] The coefficient determination module is used to fit the power-frequency response curve of the generator speed governor based on the historical frequency and historical power of the power system, and obtain the frequency coefficients of each order of the generator speed governor under the power step disturbance; based on the frequency regulation characteristics of the new energy unit, the virtual frequency regulation coefficient of the new energy unit is obtained; based on the frequency regulation characteristics of the load, the frequency coefficients of each order of the load are obtained; based on the frequency regulation characteristics of the DC FLC modulation, the frequency coefficient of the DC FLC modulation is obtained.

[0141] In one embodiment, the correction module 20 is specifically used for:

[0142] The initial frequency maximum deviation point and the initial time minimum point are input into a pre-trained back propagation neural network BPNN model to correct the initial frequency maximum deviation point and the initial time minimum point, so as to obtain the target frequency maximum deviation point corresponding to the initial frequency maximum deviation point and the target time minimum point corresponding to the target frequency maximum deviation point; wherein the BPNN model is trained based on the historical operation data of the power system; the historical operation data includes frequency, power, time, power shortage, frequency minimum point, system equivalent inertia constant, system equivalent damping constant and generator speed regulator parameters.

[0143] Each module in the above-mentioned power system frequency minimum point determination device can be implemented in whole or in part by software, hardware and a combination thereof. Each of the above-mentioned modules can be embedded in or independent of a processor in a computer device in the form of hardware, or can be stored in a memory in a computer device in the form of software, so that the processor can call and execute operations corresponding to each of the above modules.

[0144] In an exemplary embodiment, a computer device is provided, which may be a server, and its internal structure diagram may be shown in FIG8. The computer device includes a processor, a memory, an input / output interface (Input / Output, referred to as I / O) and a communication interface. The processor, the memory and the input / output interface are connected through a system bus, and the communication interface is connected to the system bus through the input / output interface. The processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the computer device is used to store power system data. The input / output interface of the computer device is used to exchange information between the processor and an external device. The communication interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, a method for determining the lowest frequency point of a power system is implemented.

[0145] Those skilled in the art will understand that the structure shown in FIG. 8 is merely a block diagram of a partial structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than shown in the figure, or combine certain components, or have a different arrangement of components.

[0146] In an exemplary embodiment, a computer device is provided, including a memory and a processor, wherein a computer program is stored in the memory, and when the processor executes the computer program, the following steps are implemented:

[0147] Based on the various order frequency coefficients of the generator speed governor under power step disturbance, the virtual frequency modulation coefficient of the new energy unit, the various order frequency coefficients of the load and the frequency coefficient of the DC frequency limit control FLC modulation in the power system, the initial frequency maximum deviation point of the power system and the initial time minimum point corresponding to the initial frequency maximum deviation point are determined; wherein, the various order frequency coefficients of the generator speed governor under power step disturbance include the zero-order frequency coefficient of the engine and the second-order frequency coefficient of the engine, and the various order frequency coefficients of the load include the zero-order frequency coefficient of the load and the first-order frequency coefficient of the load;

[0148] The initial frequency maximum deviation point and the initial time minimum point are corrected to obtain the target frequency maximum deviation point corresponding to the initial frequency maximum deviation point and the target time minimum point corresponding to the target frequency maximum deviation point.

[0149] In one embodiment, when the processor executes the computer program, the processor further implements the following steps:

[0150] Based on the frequency coefficients of each order of the generator speed regulator under the power step disturbance in the power system, the virtual frequency regulation coefficient of the new energy unit, the frequency coefficient of each order of the load, the frequency coefficient of the DC, the system equivalent damping constant and the active disturbance suffered by the system, the first frequency coefficient and the maximum deviation point of the initial frequency are determined; based on the product of the first frequency coefficient and the maximum deviation point of the initial frequency, the initial time minimum point corresponding to the maximum deviation point of the initial frequency is determined.

[0151] In one embodiment, when the processor executes the computer program, the processor further implements the following steps:

[0152] Based on the virtual frequency regulation coefficient of the new energy units in the power system, the various order frequency coefficients of the load, the frequency coefficient of the direct current and the system equivalent damping constant, the first intermediate coefficient is determined; the ratio of the second order frequency coefficient of the engine and the first intermediate coefficient is determined as the first frequency coefficient; based on the first intermediate coefficient, the zero order frequency coefficient of the load, the zero order frequency coefficient of the engine and the active disturbance suffered by the system, the maximum deviation point of the initial frequency is determined.

[0153] In one embodiment, when the processor executes the computer program, the processor further implements the following steps:

[0154] The result of adding the load zero-order frequency coefficient and the engine zero-order frequency coefficient minus the active disturbance suffered by the system is used to obtain the second intermediate coefficient; the ratio of the second intermediate coefficient to the first intermediate coefficient is determined as the maximum deviation point of the initial frequency.

[0155] In one embodiment, when the processor executes the computer program, the processor further implements the following steps:

[0156] Based on the historical frequency and historical power of the power system, the power-frequency response curve of the generator speed governor is fitted to obtain the frequency coefficients of each order of the generator speed governor under power step disturbance; based on the frequency regulation characteristics of the new energy unit, the virtual frequency regulation coefficient of the new energy unit is obtained; based on the frequency regulation characteristics of the load, the frequency coefficients of each order of the load are obtained; based on the frequency regulation characteristics of the DC FLC modulation, the frequency coefficient of the DC FLC modulation is obtained.

[0157] In one embodiment, when the processor executes the computer program, the processor further implements the following steps:

[0158] The initial frequency maximum deviation point and the initial time minimum point are input into a pre-trained back propagation neural network BPNN model to correct the initial frequency maximum deviation point and the initial time minimum point, so as to obtain the target frequency maximum deviation point corresponding to the initial frequency maximum deviation point and the target time minimum point corresponding to the target frequency maximum deviation point; wherein the BPNN model is trained based on the historical operation data of the power system; the historical operation data includes frequency, power, time, power shortage, frequency minimum point, system equivalent inertia constant, system equivalent damping constant and generator speed regulator parameters.

[0159] In one embodiment, a computer readable storage medium is provided, on which a computer program is stored, and when the computer program is executed by a processor, the following steps are implemented:

[0160] Based on the various order frequency coefficients of the generator speed governor under power step disturbance, the virtual frequency modulation coefficient of the new energy unit, the various order frequency coefficients of the load and the frequency coefficient of the DC frequency limit control FLC modulation in the power system, the initial frequency maximum deviation point of the power system and the initial time minimum point corresponding to the initial frequency maximum deviation point are determined; wherein, the various order frequency coefficients of the generator speed governor under power step disturbance include the zero-order frequency coefficient of the engine and the second-order frequency coefficient of the engine, and the various order frequency coefficients of the load include the zero-order frequency coefficient of the load and the first-order frequency coefficient of the load;

[0161] The initial frequency maximum deviation point and the initial time minimum point are corrected to obtain the target frequency maximum deviation point corresponding to the initial frequency maximum deviation point and the target time minimum point corresponding to the target frequency maximum deviation point.

[0162] In one embodiment, when the computer program is executed by a processor, the following steps are also implemented:

[0163] Based on the frequency coefficients of each order of the generator speed regulator under the power step disturbance in the power system, the virtual frequency regulation coefficient of the new energy unit, the frequency coefficient of each order of the load, the frequency coefficient of the DC, the system equivalent damping constant and the active disturbance suffered by the system, the first frequency coefficient and the maximum deviation point of the initial frequency are determined; based on the product of the first frequency coefficient and the maximum deviation point of the initial frequency, the initial time minimum point corresponding to the maximum deviation point of the initial frequency is determined.

[0164] In one embodiment, when the computer program is executed by a processor, the following steps are also implemented:

[0165] Based on the virtual frequency regulation coefficient of the new energy units in the power system, the various order frequency coefficients of the load, the frequency coefficient of the direct current and the system equivalent damping constant, the first intermediate coefficient is determined; the ratio of the second order frequency coefficient of the engine and the first intermediate coefficient is determined as the first frequency coefficient; based on the first intermediate coefficient, the zero order frequency coefficient of the load, the zero order frequency coefficient of the engine and the active disturbance suffered by the system, the maximum deviation point of the initial frequency is determined.

[0166] In one embodiment, when the computer program is executed by a processor, the following steps are also implemented:

[0167] The result of adding the load zero-order frequency coefficient and the engine zero-order frequency coefficient minus the active disturbance suffered by the system is used to obtain the second intermediate coefficient; the ratio of the second intermediate coefficient to the first intermediate coefficient is determined as the maximum deviation point of the initial frequency.

[0168] In one embodiment, when the computer program is executed by a processor, the following steps are also implemented:

[0169] Based on the historical frequency and historical power of the power system, the power-frequency response curve of the generator speed governor is fitted to obtain the frequency coefficients of each order of the generator speed governor under power step disturbance; based on the frequency regulation characteristics of the new energy unit, the virtual frequency regulation coefficient of the new energy unit is obtained; based on the frequency regulation characteristics of the load, the frequency coefficients of each order of the load are obtained; based on the frequency regulation characteristics of the DC FLC modulation, the frequency coefficient of the DC FLC modulation is obtained.

[0170] In one embodiment, when the computer program is executed by a processor, the following steps are also implemented:

[0171] The initial frequency maximum deviation point and the initial time minimum point are input into a pre-trained back propagation neural network BPNN model to correct the initial frequency maximum deviation point and the initial time minimum point, so as to obtain the target frequency maximum deviation point corresponding to the initial frequency maximum deviation point and the target time minimum point corresponding to the target frequency maximum deviation point; wherein the BPNN model is trained based on the historical operation data of the power system; the historical operation data includes frequency, power, time, power shortage, frequency minimum point, system equivalent inertia constant, system equivalent damping constant and generator speed regulator parameters.

[0172] In one embodiment, a computer program product is provided, comprising a computer program, which, when executed by a processor, implements the following steps:

[0173] Based on the various order frequency coefficients of the generator speed governor under power step disturbance, the virtual frequency modulation coefficient of the new energy unit, the various order frequency coefficients of the load and the frequency coefficient of the DC frequency limit control FLC modulation in the power system, the initial frequency maximum deviation point of the power system and the initial time minimum point corresponding to the initial frequency maximum deviation point are determined; wherein, the various order frequency coefficients of the generator speed governor under power step disturbance include the zero-order frequency coefficient of the engine and the second-order frequency coefficient of the engine, and the various order frequency coefficients of the load include the zero-order frequency coefficient of the load and the first-order frequency coefficient of the load;

[0174] The initial frequency maximum deviation point and the initial time minimum point are corrected to obtain the target frequency maximum deviation point corresponding to the initial frequency maximum deviation point and the target time minimum point corresponding to the target frequency maximum deviation point.

[0175] In one embodiment, when the computer program is executed by a processor, the following steps are also implemented:

[0176] Based on the frequency coefficients of each order of the generator speed regulator under the power step disturbance in the power system, the virtual frequency regulation coefficient of the new energy unit, the frequency coefficient of each order of the load, the frequency coefficient of the DC, the system equivalent damping constant and the active disturbance suffered by the system, the first frequency coefficient and the maximum deviation point of the initial frequency are determined; based on the product of the first frequency coefficient and the maximum deviation point of the initial frequency, the initial time minimum point corresponding to the maximum deviation point of the initial frequency is determined.

[0177] In one embodiment, when the computer program is executed by a processor, the following steps are also implemented:

[0178] Based on the virtual frequency regulation coefficient of the new energy units in the power system, the various order frequency coefficients of the load, the frequency coefficient of the direct current and the system equivalent damping constant, the first intermediate coefficient is determined; the ratio of the second order frequency coefficient of the engine and the first intermediate coefficient is determined as the first frequency coefficient; based on the first intermediate coefficient, the zero order frequency coefficient of the load, the zero order frequency coefficient of the engine and the active disturbance suffered by the system, the maximum deviation point of the initial frequency is determined.

[0179] In one embodiment, when the computer program is executed by a processor, the following steps are also implemented:

[0180] The result of adding the load zero-order frequency coefficient and the engine zero-order frequency coefficient minus the active disturbance suffered by the system is used to obtain the second intermediate coefficient; the ratio of the second intermediate coefficient to the first intermediate coefficient is determined as the maximum deviation point of the initial frequency.

[0181] In one embodiment, when the computer program is executed by a processor, the following steps are also implemented:

[0182] Based on the historical frequency and historical power of the power system, the power-frequency response curve of the generator speed governor is fitted to obtain the frequency coefficients of each order of the generator speed governor under power step disturbance; based on the frequency regulation characteristics of the new energy unit, the virtual frequency regulation coefficient of the new energy unit is obtained; based on the frequency regulation characteristics of the load, the frequency coefficients of each order of the load are obtained; based on the frequency regulation characteristics of the DC FLC modulation, the frequency coefficient of the DC FLC modulation is obtained.

[0183] In one embodiment, when the computer program is executed by a processor, the following steps are also implemented:

[0184] The initial frequency maximum deviation point and the initial time minimum point are input into a pre-trained back propagation neural network BPNN model to correct the initial frequency maximum deviation point and the initial time minimum point, so as to obtain the target frequency maximum deviation point corresponding to the initial frequency maximum deviation point and the target time minimum point corresponding to the target frequency maximum deviation point; wherein the BPNN model is trained based on the historical operation data of the power system; the historical operation data includes frequency, power, time, power shortage, frequency minimum point, system equivalent inertia constant, system equivalent damping constant and generator speed regulator parameters.

[0185] It should be noted that the information (including but not limited to power system information, power system equipment information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data fully authorized by all parties, and the collection, use and processing of relevant data must comply with relevant regulations.

[0186] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. Non-relational databases may include distributed databases based on blockchains, etc., but are not limited to this. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., but are not limited to this.

[0187] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0188] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A method for determining the lowest frequency point of a power system, It is characterized in that The method comprises: Based on the various order frequency coefficients of the generator speed regulator under the power step disturbance, the virtual frequency modulation coefficient of the new energy unit, the various order frequency coefficients of the load and the frequency coefficient of the DC frequency limit control FLC modulation in the power system, the initial frequency maximum deviation point of the power system and the initial time minimum point corresponding to the initial frequency maximum deviation point are determined; wherein the various order frequency coefficients of the generator speed regulator under the power step disturbance include the engine zero-order frequency coefficient and the engine second-order frequency coefficient, and the various order frequency coefficients of the load include the load zero-order frequency coefficient and the load first-order frequency coefficient; The initial frequency maximum deviation point and the initial time minimum point are corrected to obtain a target frequency maximum deviation point corresponding to the initial frequency maximum deviation point and a target time minimum point corresponding to the target frequency maximum deviation point.

2. The method according to claim 1, It is characterized in that The method determines the initial frequency maximum deviation point of the power system and the initial time minimum point corresponding to the initial frequency maximum deviation point based on the frequency coefficients of each order of the generator speed regulator under the power step disturbance, the virtual frequency modulation coefficient of the new energy unit, the frequency coefficients of each order of the load and the frequency coefficient of the DC frequency limit control FLC modulation in the power system, including: Determine the first frequency coefficient and the maximum deviation point of the initial frequency based on the frequency coefficients of each order of the generator speed regulator under the power step disturbance, the virtual frequency regulation coefficient of the new energy unit, the frequency coefficient of each order of the load, the frequency coefficient of the direct current, the system equivalent damping constant and the active disturbance suffered by the system in the power system; Based on the product of the first frequency coefficient and the initial frequency maximum deviation point, the initial time lowest point corresponding to the initial frequency maximum deviation point is determined.

3. The method according to claim 2, It is characterized in that The method comprises: determining the first frequency coefficient and the maximum deviation point of the initial frequency based on the frequency coefficients of each order of the generator speed regulator under the power step disturbance, the virtual frequency regulation coefficient of the new energy unit, the frequency coefficient of each order of the load, the frequency coefficient of the direct current, the system equivalent damping constant and the active disturbance suffered by the system, including: Determine the first intermediate coefficient based on the virtual frequency regulation coefficient of the new energy unit in the power system, the frequency coefficients of each order of the load, the frequency coefficient of the direct current and the system equivalent damping constant; Determine the ratio of the second-order frequency coefficient of the engine to the first intermediate coefficient as the first frequency coefficient; The initial frequency maximum deviation point is determined based on the first intermediate coefficient, the load zero-order frequency coefficient, the engine zero-order frequency coefficient and the active power disturbance amount suffered by the system.

4. The method according to claim 3, It is characterized in that The step of determining the maximum deviation point of the initial frequency based on the first intermediate coefficient, the load zero-order frequency coefficient, the engine zero-order frequency coefficient and the active disturbance amount suffered by the system comprises: The active disturbance amount suffered by the system is subtracted from the result of adding the load zero-order frequency coefficient and the engine zero-order frequency coefficient to obtain a second intermediate coefficient; The ratio of the second intermediate coefficient to the first intermediate coefficient is determined as the initial frequency maximum deviation point.

5. The method according to claim 1, It is characterized in that The method further comprises at least one of the following: Based on the historical frequency and historical power of the power system, the power-frequency response curve of the generator speed governor is fitted to obtain the frequency coefficients of each order of the generator speed governor under the power step disturbance; Based on the frequency regulation characteristics of the new energy units, the virtual frequency regulation coefficient of the new energy units is obtained; Based on the frequency modulation characteristics of the load, obtain the frequency coefficients of each order of the load; Based on the frequency modulation characteristics of the DC FLC modulation, the frequency coefficient of the DC FLC modulation is obtained.

6. The method according to claim 1, It is characterized in that The step of correcting the initial frequency maximum deviation point and the initial time minimum point to obtain a target frequency maximum deviation point corresponding to the initial frequency maximum deviation point and a target time minimum point corresponding to the target frequency maximum deviation point includes: The initial frequency maximum deviation point and the initial time minimum point are input into a pre-trained back propagation neural network BPNN model to correct the initial frequency maximum deviation point and the initial time minimum point to obtain the target frequency maximum deviation point corresponding to the initial frequency maximum deviation point and the target time minimum point corresponding to the target frequency maximum deviation point; wherein the BPNN model is trained based on the historical operation data of the power system; the historical operation data includes frequency, power, time, power shortage, frequency minimum point, system equivalent inertia constant, system equivalent damping constant and generator speed regulator parameters.

7. A device for determining the lowest frequency point of a power system, It is characterized in that The device comprises: An initial determination module is used to determine the initial frequency maximum deviation point of the power system and the initial time minimum point corresponding to the initial frequency maximum deviation point based on the various order frequency coefficients of the generator speed regulator under power step disturbance, the virtual frequency modulation coefficient of the new energy unit, the various order frequency coefficients of the load and the frequency coefficient of the DC frequency limit control FLC modulation in the power system; wherein the various order frequency coefficients of the generator speed regulator under power step disturbance include the engine zero-order frequency coefficient and the engine second-order frequency coefficient, and the various order frequency coefficients of the load include the load zero-order frequency coefficient and the load first-order frequency coefficient; The correction module is used to correct the initial frequency maximum deviation point and the initial time minimum point to obtain the target frequency maximum deviation point corresponding to the initial frequency maximum deviation point and the target time minimum point corresponding to the target frequency maximum deviation point.

8. A computer device comprising a memory and a processor, wherein the memory stores a computer program. It is characterized in that When the processor executes the computer program, the steps of the method according to any one of claims 1 to 6 are implemented.

9. A computer-readable storage medium having a computer program stored thereon, It is characterized in that When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

10. A computer program product comprising a computer program, It is characterized in that When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

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