Frequency dynamic trajectory prediction method and device, electronic equipment and storage medium

Abstract

The invention discloses a frequency dynamic trajectory prediction method and device, electronic equipment and a storage medium, which are used for solving the technical problems that the real-time performance of the current related technology is difficult to meet the requirement of online prediction and is not suitable for a low-damping power grid. The method comprises the following steps: considering active power flow distribution and synchronous machine rotor motion in a power system, and constructing a state space model of primary frequency modulation of the power system; based on the state space model, establishing a disturbance information extraction model at the moment of disturbance occurrence; according to the disturbance information extraction model, solving a disturbance vector of the power system after disturbance; and performing trajectory prediction by combining the state space model and the disturbance vector to obtain a frequency dynamic trajectory of the power system. The method is not only suitable for online prediction, but also can solve the defect that the traditional technology is not suitable for a low-damping power grid, provides reference for operation of a new energy power system, and guarantees safe and stable operation of the system.

Description

Technical Field

[0001] This invention relates to the field of power system technology, and in particular to a method, apparatus, electronic device, and storage medium for predicting frequency dynamic trajectory. Background Technology

[0002] As the proportion of new energy sources in primary energy gradually increases, the dominant position of synchronous generator units will be weakened, and a large number of power electronic sources will be connected to the grid. Since these power electronic sources do not have the function of participating in the primary frequency regulation of the system under normal control, the overall primary frequency regulation capability of the system will decrease significantly. This deficiency will directly lead to a significant decline in power quality, and may even trigger grid disconnection, posing a serious threat to the safe and stable operation of the power system and causing significant economic losses.

[0003] In recent years, various novel control strategies have been proposed using traditional technologies to achieve the goal of enabling power electronic power sources to participate in system frequency regulation. The diverse control strategies and complex response characteristics of power electronic power sources have made the system frequency response increasingly complex, posing a significant challenge to frequency stability assessment. The output of new energy units exhibits randomness and volatility. Simultaneously, the high penetration rate of new energy sources will severely reduce the frequency stability margin of the power grid. In synchronous generator-dominated power systems, the frequency stability of the system is typically checked offline based on the maximum possible disturbance. However, this method is highly conservative and is generally difficult to implement in power systems with high new energy penetration. In such systems, online assessment of the system's dynamic frequency trajectory and proactive implementation of stability control measures is an economical and effective approach.

[0004] Dynamic frequency trajectory prediction is a key technology for improving primary frequency regulation performance. However, current dynamic frequency trajectory prediction methods have two shortcomings. Firstly, the real-time performance of current methods is insufficient for online prediction. This is because traditional methods typically require a certain length of time series as the basis for trajectory fitting, inevitably reducing the timeliness of prediction. Secondly, traditional dynamic frequency trajectory prediction methods usually assume that the entire system shares a unified frequency, predicting the dynamic frequency trajectory under a single disturbance. This approach is not suitable for low-damped power grids. Therefore, there is an urgent need to propose a highly timely dynamic frequency trajectory prediction method to address the problems faced by current related technologies. Summary of the Invention

[0005] This invention provides a frequency dynamic trajectory prediction method, device, electronic device, and storage medium to solve or partially solve the technical problem that current related technologies are unable to meet the requirements of online prediction in terms of real-time performance and are not applicable to low-damped power grids.

[0006] This invention provides a frequency dynamic trajectory prediction method, the method comprising:

[0007] Considering the active power flow distribution and synchronous machine rotor motion in the power system, a state-space model of the primary frequency regulation of the power system is constructed.

[0008] Based on the state-space model, a disturbance information extraction model is established at the instant the disturbance occurs;

[0009] Based on the disturbance information extraction model, the disturbance vector of the power system after the disturbance occurs is calculated;

[0010] By combining the state-space model and the disturbance vector, frequency trajectory prediction is performed to obtain the dynamic frequency trajectory of the power system.

[0011] Optionally, the process of constructing a state-space model for primary frequency regulation of the power system, considering the active power flow distribution and synchronous machine rotor motion, includes:

[0012] Considering the active power flow distribution of the power system, a DC power flow model is constructed;

[0013] Based on the DC power flow model, the electromagnetic power change vector of the synchronous machine in the power system and the output power change vector of the frequency-modulated asynchronous machine power supply are derived through model simplification.

[0014] Based on the key operating parameters of the synchronous machine in the power system, the synchronous machine rotor motion equation and the simplified model of the speed governor are constructed.

[0015] Simultaneously considering the bus frequency offset, virtual inertia, and virtual damping coefficient of the frequency-regulating asynchronous power supply in the power system, a virtual synchronous control model is constructed.

[0016] Based on the DC power flow model, the electromagnetic power change vector, the output power change vector, the synchronous machine rotor motion equation, the simplified speed governor model, and the virtual synchronous control model, a state-space model for the primary frequency regulation of the power system is constructed.

[0017] Optionally, the construction of a DC power flow model considering the active power flow distribution of the power system includes:

[0018] Simultaneously considering the electromagnetic power change vector and power angle vector of the synchronous machine in the power system, the output power change vector and phase vector of the frequency-modulated asynchronous machine power supply, the load change vector and load bus vector, and combining the admittance block matrix, a DC power flow model is constructed.

[0019] Optionally, the key operating parameters include power angle, speed variation, mechanical power, electromagnetic power, rotor inertia time constant, damping coefficient, reheat time constant, droop coefficient, and high-pressure boiler ratio; the construction of the synchronous machine rotor motion equation and simplified speed governor model based on the key operating parameters of the synchronous machine in the power system includes:

[0020] Based on the power angle, the change in rotational speed, the mechanical power, the electromagnetic power, the rotor inertia time constant, and the damping coefficient, the synchronous machine rotor motion equation is constructed.

[0021] A simplified model of the governor is constructed based on the reheat time constant, the droop coefficient, and the proportion of high-pressure boiler.

[0022] Optionally, the step of establishing a disturbance information extraction model at the instant of disturbance occurrence based on the state-space model includes:

[0023] Construct the frequency dynamic trajectory model of the state-space model at the instant the disturbance occurs;

[0024] A transformation matrix is ​​introduced to transform the frequency dynamic trajectory model into a feature root vector model, which serves as a disturbance information extraction model at the moment the disturbance occurs.

[0025] Optionally, the step of solving the disturbance vector of the power system after a disturbance occurs based on the disturbance information extraction model includes:

[0026] Obtain the current system state and substitute the current system state into the disturbance information extraction model;

[0027] The disturbance information extraction model, which incorporates the current system state, is differentiated to obtain the state variable change rate model of the power system after the disturbance occurs; the state variable change rate model includes the disturbance vector to be solved.

[0028] Based on the disturbance vector to be solved, and considering the abrupt changes in the rate of change of rotational speed and frequency caused by the disturbance, an equivalent model of the difference matrix is ​​constructed; the difference matrix is ​​introduced into the equivalent model of the difference matrix.

[0029] Obtain the measured rate of change of the rotational speed and frequency of the power system at each moment after the disturbance occurs;

[0030] For each time moment, calculate the angle between the measured rate of change mutation and each column vector in the difference matrix;

[0031] Determine the position of the column vector with the smallest included angle in the difference matrix, and determine the perturbation position based on the vector position;

[0032] Based on the frequency change rate and moment of inertia of all synchronous and asynchronous power supplies in the power system at the specified time, the disturbance value of the load at the disturbance location at the specified time is calculated.

[0033] By integrating the disturbance values ​​at various times after the disturbance occurs, a disturbance vector of the power system after the disturbance occurs is constructed.

[0034] Optionally, the solution of the state-space model at the instant of the disturbance is represented as a frequency dynamic trajectory model; the step of combining the state-space model and the disturbance vector to predict the frequency trajectory and obtain the frequency dynamic trajectory of the power system includes:

[0035] The disturbance vector is substituted into the frequency dynamic trajectory model, and the frequency trajectory prediction calculation is performed through the frequency dynamic trajectory model to obtain the frequency dynamic trajectory of the power system after the disturbance occurs.

[0036] The present invention also provides a frequency dynamic trajectory prediction device, comprising:

[0037] The state-space model building unit is used to construct the state-space model of the primary frequency regulation of the power system, taking into account the active power flow distribution and synchronous machine rotor motion in the power system.

[0038] The disturbance information extraction model establishment unit is used to establish a disturbance information extraction model at the instant of disturbance occurrence based on the state space model.

[0039] The disturbance vector solving unit is used to extract the model based on the disturbance information and solve the disturbance vector of the power system after the disturbance occurs.

[0040] The frequency trajectory prediction unit is used to combine the state-space model and the disturbance vector to predict the frequency trajectory and obtain the dynamic frequency trajectory of the power system.

[0041] The present invention also provides an electronic device, the device comprising a processor and a memory:

[0042] The memory is used to store program code and transmit the program code to the processor;

[0043] The processor is configured to execute the frequency dynamic trajectory prediction method as described above, according to the instructions in the program code.

[0044] The present invention also provides a computer-readable storage medium for storing program code for performing the frequency dynamic trajectory prediction method as described in any of the preceding claims.

[0045] As can be seen from the above technical solutions, the present invention has the following advantages:

[0046] A frequency dynamic trajectory prediction method based on modal analysis is proposed. First, considering the active power flow distribution and synchronous machine rotor motion in the power system, a state-space model of the power system's primary frequency regulation is constructed. Then, based on the state-space model, a disturbance information extraction model is established at the instant of a disturbance. Next, according to the disturbance information extraction model, the disturbance vector of the power system after the disturbance occurs is solved. Finally, the frequency trajectory is predicted by combining the state-space model and the disturbance vector to obtain the power system's frequency dynamic trajectory. The technical solution provided by this invention can effectively predict subsequent frequency dynamic trajectories using the disturbance information extracted from the state-space model and the system state change rate information. It is not only applicable to online prediction but also overcomes the limitation of traditional techniques in low-damped power grids, providing a reference for the operation of new energy power systems and ensuring the safe and stable operation of the system. Attached Figure Description

[0047] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0048] Figure 1 A flowchart illustrating the steps of a frequency dynamic trajectory prediction method;

[0049] Figure 2 This is a schematic diagram of the overall process of a frequency dynamic trajectory prediction method.

[0050] Figure 3 This is an example diagram of the modified IEEE 39-node system network topology.

[0051] Figure 4 Example graph showing the comparison between simulation results and prediction results of frequency response for some units;

[0052] Figure 5 This is a structural block diagram of a frequency dynamic trajectory prediction device. Detailed Implementation

[0053] This invention provides a frequency dynamic trajectory prediction method, device, electronic device, and storage medium to solve or partially solve the technical problem that current related technologies are unable to meet the requirements of online prediction in terms of real-time performance and are not applicable to low-damped power grids.

[0054] To make the objectives, features, and advantages of this invention more apparent and understandable, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described below are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0055] As an example, in power systems with high penetration of new energy sources, online assessment of the system's dynamic frequency trajectory and proactive implementation of stabilization measures are an economical and effective approach. Dynamic frequency trajectory prediction is a key technology for improving primary frequency regulation performance. However, current dynamic frequency trajectory prediction methods have two shortcomings. First, the real-time performance of current trajectory prediction methods is insufficient for online prediction. This is because traditional methods typically require a certain length of time series as the basis for trajectory fitting, inevitably reducing the timeliness of prediction. Second, traditional dynamic frequency trajectory prediction methods usually assume that the entire system shares a unified frequency, predicting the dynamic frequency trajectory under a single disturbance. This approach is not suitable for low-damped power grids. Therefore, there is an urgent need to propose a highly timely dynamic frequency trajectory prediction method to address the problems faced by current related technologies.

[0056] Therefore, one of the core inventive points of this invention is to propose a frequency dynamic trajectory prediction method based on modal analysis. First, considering the active power flow distribution and synchronous machine rotor motion in the power system, a state-space model of the system's primary frequency regulation is established. Then, based on the state-space model, disturbance information is extracted. Furthermore, based on the disturbance information and combined with modal analysis, the subsequent frequency dynamic trajectory is predicted to obtain the frequency dynamic trajectory prediction result. The technical solution provided by this invention can effectively utilize the system state change rate information to predict the subsequent frequency dynamic trajectory based on the disturbance information extracted from the state-space model. It is not only applicable to online prediction but also solves the deficiency of traditional technologies being unsuitable for low-damped power grids, providing a reference for the operation of new energy power systems and ensuring the safe and stable operation of the system.

[0057] Reference Figure 1 The diagram illustrates a flowchart of a frequency dynamic trajectory prediction method provided by an embodiment of the present invention, which may specifically include the following steps:

[0058] Step 101: Considering the active power flow distribution and synchronous machine rotor motion in the power system, construct the state-space model of the primary frequency regulation of the power system.

[0059] This invention achieves frequency dynamic trajectory prediction of the system through modal analysis. Therefore, this step mainly establishes the state-space model of the system's primary frequency modulation.

[0060] In some embodiments, considering the active power flow distribution and synchronous machine rotor motion in the power system, the implementation process of constructing the state-space model of the primary frequency regulation of the power system may specifically include the following steps S01 to S05:

[0061] Step S01: Consider the active power flow distribution of the power system and construct a DC power flow model;

[0062] Step S02: Based on the DC power flow model, through model simplification, derive the electromagnetic power change vector of the synchronous machine in the power system, and the output power change vector of the power supply of the frequency-modulated asynchronous machine.

[0063] Step S03: Based on the key operating parameters of the synchronous machine in the power system, construct the synchronous machine rotor motion equation and the simplified model of the speed governor;

[0064] Step S04: Simultaneously consider the bus frequency offset, virtual inertia, and virtual damping coefficient of the frequency-regulating asynchronous power supply in the power system, and construct a virtual synchronous control model.

[0065] Step S05: Based on the DC power flow model, electromagnetic power change vector, output power change vector, synchronous machine rotor motion equation, speed governor simplified model and virtual synchronous control model, construct the state space model of primary frequency regulation of the power system.

[0066] Furthermore, the process of constructing a DC power flow model in step S01, which considers the active power flow distribution of the power system, may specifically include: simultaneously considering the electromagnetic power change vector and power angle vector of the synchronous machine in the power system, the output power change vector and phase vector of the frequency-modulated asynchronous machine power supply, the load change vector and the load bus vector, and combining the admittance block matrix to construct a DC power flow model.

[0067] Furthermore, the key operating parameters of the synchronous machine in the power system mentioned in step S03 may include the power angle, speed change, mechanical power, electromagnetic power, rotor inertia time constant, damping coefficient, reheat time constant, droop coefficient, and the proportion of high-pressure boilers. Therefore, the specific implementation process for constructing the synchronous machine rotor motion equation and the simplified governor model based on the key operating parameters of the synchronous machine in the power system may include: constructing the synchronous machine rotor motion equation based on the power angle, speed change, mechanical power, electromagnetic power, rotor inertia time constant, and damping coefficient; and constructing the simplified governor model based on the reheat time constant, droop coefficient, and the proportion of high-pressure boilers.

[0068] Specifically, the frequency shift in an AC power grid is caused by active power imbalance. In a transmission network, changes in active power have a negligible impact on AC voltage. Therefore, in frequency analysis, the distribution of reactive power and the influence of AC voltage in the grid can generally be ignored. In this embodiment of the invention, the DC power flow model shown in the following equation is used to simulate the distribution of active power flow in the network:

[0069]

[0070] in, A vector composed of the changes in the electromagnetic power of the synchronizing machine; This represents the output power change vector of the power supply participating in the frequency modulation asynchronous machine; This represents the vector composed of load changes (i.e., the disturbance vector to be solved). , , , , , , , , Represents the admittance block matrix; This is a vector composed of the power angles of the synchronizing machine; A vector composed of the phases of the asynchronous machine's power supply; This represents the vector composed of load buses.

[0071] By simplifying the model, eliminate The electromagnetic power change vector of the synchronous machine in the power system can be obtained as follows:

[0072]

[0073] in,

[0074]

[0075] Similarly, the output power change vector of the power supply participating in the frequency modulation asynchronous machine can be obtained as follows:

[0076]

[0077] in,

[0078]

[0079] The rotor motion equation of the synchronous machine can be expressed as:

[0080]

[0081] in, and They represent the first The power angle and speed variation of each synchronous machine; and They represent the first The mechanical and electromagnetic power of a synchronous machine; and These represent the rotor inertia time constant and damping coefficient of the synchronous machine, respectively.

[0082] Mechanical power change Determined by the speed governor. A simplified model of the speed governor can be written as:

[0083]

[0084] In the formula, For the first The reheat time constant of a synchronous machine; For the first The droop coefficient of each synchronizer; For the first The proportion of high-pressure boilers in a single synchronous machine.

[0085] Furthermore, considering that the asynchronous power supply uses virtual synchronous control to participate in frequency modulation, then the first... Phase change of the bus connected to the asynchronous power supply and output power change The virtual synchronization control model shown below should be satisfied:

[0086]

[0087] In the formula, This refers to the frequency offset of the bus connected to the asynchronous machine power supply. The virtual inertia of the asynchronous machine power supply; This is the virtual damping coefficient of the asynchronous machine power supply.

[0088] Based on the models constructed above, the following state-space model of the system's primary frequency regulation can be obtained through integration:

[0089]

[0090]

[0091]

[0092]

[0093]

[0094] In the formula, The state-space system matrix; Input matrix to state space; It is a vector composed of the changes in the mechanical power of the synchronizing machine; A vector composed of the changes in the synchronous machine's rotational speed; A vector composed of the frequency changes of the asynchronous machine's power supply. and These are the rotor inertia vector and damping vector of the synchronous machine; and Represents the virtual inertia and damping vector of the asynchronous machine power supply; A vector consisting of the droop coefficients of the synchronizing machine; A vector composed of the proportion of high-pressure boilers in the synchronous machine; It is a vector consisting of the reheat time constants of the synchronous machine.

[0095] Step 102: Based on the state-space model, establish a disturbance information extraction model at the instant the disturbance occurs;

[0096] In this embodiment of the invention, steps 102 and 103 mainly establish a disturbance information extraction method. Specifically, this step is primarily based on the state-space model constructed in the preceding steps, establishing a disturbance information extraction model for the instant the disturbance occurs.

[0097] In some embodiments, the implementation process of establishing a disturbance information extraction model at the moment of disturbance occurrence based on a state-space model may specifically include: firstly, constructing a frequency dynamic trajectory model of the state-space model at the moment of disturbance occurrence; then introducing a transformation matrix to transform the frequency dynamic trajectory model into a feature root vector model, which serves as the disturbance information extraction model at the moment of disturbance occurrence.

[0098] Specifically, at the instant the disturbance occurs, the solution of the state-space model can be represented as the frequency dynamic trajectory model shown below:

[0099]

[0100] in, It is a unit vector; Let be the perturbation vector, where one element is non-zero and the others are zero.

[0101] Further development yields the following eigenvector model (defined in this embodiment as a disturbance information extraction model at the instant of disturbance occurrence):

[0102]

[0103] in, The transformation matrix; The number of state variables; These are characteristic roots.

[0104] Step 103: Based on the disturbance information extraction model, solve for the disturbance vector of the power system after the disturbance occurs;

[0105] This step mainly uses the disturbance information extraction model constructed in the previous steps to solve for the disturbance vector of the power system after a disturbance occurs. In some embodiments, the implementation process of solving for the disturbance vector of the power system after a disturbance occurs based on the disturbance information extraction model may specifically include the following steps S11 to S18:

[0106] Step S11: Obtain the current system state and substitute it into the disturbance information extraction model;

[0107] Step S12: Differentiate the disturbance information extraction model that incorporates the current system state to obtain the state variable change rate model of the power system after the disturbance occurs; the state variable change rate model includes the disturbance vector to be solved;

[0108] Step S13: Based on the disturbance vector to be solved, and considering the abrupt changes in the rate of change of rotational speed and frequency caused by the disturbance, construct an equivalent model of the difference matrix; the difference matrix is ​​introduced into the equivalent model of the difference matrix.

[0109] Step S14: Obtain the measured rate of change of the rotational speed and frequency of the power system at each moment after the disturbance occurs;

[0110] For each moment, the load disturbance value can be solved by performing steps S15 to S17:

[0111] Step S15: Calculate the angle between the measured rate of change mutation and each column vector in the difference matrix one by one;

[0112] Step S16: Determine the position of the column vector with the smallest included angle in the difference matrix, and determine the perturbation position based on the vector position;

[0113] Step S17: Based on the frequency change rate and moment of inertia of all synchronous and asynchronous power supplies in the power system at time t, solve for the disturbance value of the load at the disturbance location at time t.

[0114] Step S18: Integrate the disturbance values ​​at each time point after the disturbance occurs to construct the disturbance vector of the power system after the disturbance occurs.

[0115] Specifically, the rate of change of the system's state variables after a disturbance is:

[0116]

[0117] When the system is subjected to disturbances, the current system state can be determined through measurement. Assuming the location and magnitude of the disturbance are known, the disturbance vector can be determined. This allows for easy acquisition of the time-domain expressions for the speed of each unit and the frequency of the asynchronous power supply bus under disturbance. Conversely, attempting to derive the derivative given the abrupt change in the rate of frequency change is problematic. However, it is extremely difficult. The reason is that the number of unknowns and the number of equations are not equal.

[0118] Further analysis suggests that the system contains... One synchronizer, Given an asynchronous power supply, the known rate of change of the unit or bus frequency is: The number of equations that can be used is (the number of equations is ). However, in reality, there is no necessary correlation between the number of loads and the number of generators and asynchronous power sources. A can have any number of elements, thus leading to There is either no solution or infinitely many solutions. In reality, the probability of active disturbances occurring simultaneously at both points is very small. Therefore, There is usually only one non-zero element in a set. The non-zero element is in... The location within is unknown. Generally speaking, Two elements in different positions cause all The probability of having the same rate of change is extremely small. Therefore, the location of the disturbance can be determined by the proportional relationship between the rates of change of different frequencies, and the magnitude of the disturbance can be determined by the magnitude of the rate of change.

[0119] Next, we will explain in detail how to determine the size and location of the disturbance.

[0120] The rate of change of the state variables consists of two parts: the first part is determined by the previous system operating state, and the second part is caused by the disturbance. Taking into account the portion related to the unit speed and the frequency of the asynchronous power supply bus, and considering the abrupt changes in the rate of change of speed and frequency due to the disturbance, an equivalent difference matrix model can be constructed as shown below:

[0121]

[0122] in, It is a difference matrix.

[0123] Select matrix The first in Column vector, represented as The abrupt changes in the rotational speed and frequency rate obtained from the actual measurements in the system will be used to form a vector. Then the vector and The included angle between them can be expressed as:

[0124]

[0125] in, For vectors and The angle between them.

[0126] Assumption for Column vectors and The smallest angle between the vectors is then the vectors The Middle The element represents the location of the perturbation. The perturbation location can be determined by the following formula:

[0127]

[0128] This indicates the location of the disturbance, i.e., the disturbance vector. The position of the non-zero element.

[0129] Once the location of the disturbance is determined, the magnitude of the disturbance at that location can be accurately calculated using the measured rotational speed and frequency change rate. The frequency change rate multiplied by the moment of inertia equals the unbalanced power of the synchronous or asynchronous power supply. At the very beginning of the disturbance, because the speed governor of the synchronous machine unit has not yet activated, the sum of the unbalanced power of all synchronous or asynchronous power supplies is the magnitude of the load disturbance. Specifically, the disturbance value at the disturbance location at a certain moment after the disturbance occurs can be calculated using the following formula:

[0130]

[0131] in, For the first The inertia of a power source. For the first The frequency of the power supply.

[0132] Step 104: Combine the state-space model and the disturbance vector to predict the frequency trajectory and obtain the dynamic frequency trajectory of the power system.

[0133] This step mainly uses the disturbance vector obtained in the previous steps to calculate the frequency dynamic trajectory of the dynamic system after the disturbance.

[0134] Based on the preceding discussion, the solution of the state-space model constructed in this embodiment of the invention at the instant of disturbance is represented as a frequency dynamic trajectory model. The process of combining the state-space model and the disturbance vector to predict the frequency trajectory and obtain the frequency dynamic trajectory of the power system can specifically include: substituting the disturbance vector into the frequency dynamic trajectory model, performing frequency trajectory prediction calculations through the frequency dynamic trajectory model, and obtaining the frequency dynamic trajectory of the power system after the disturbance occurs.

[0135] Specifically, after obtaining the estimated result of the disturbance vector, the frequency dynamic trajectory can be calculated using the following formula (for simplicity, the disturbance vector is not considered in the calculation). (Impact)

[0136]

[0137] In the formula, This is the perturbation vector obtained through the aforementioned perturbation information extraction process.

[0138] This invention proposes a frequency dynamic trajectory prediction method based on modal analysis. First, considering the active power flow distribution and synchronous machine rotor motion in the power system, a state-space model of the system's primary frequency regulation is established. Then, based on the state-space model, disturbance information is extracted. Finally, based on the disturbance information and combined with modal analysis, the subsequent frequency dynamic trajectory is predicted, yielding the predicted frequency dynamic trajectory result. The technical solution provided by this invention can effectively utilize the system state change rate information to predict the subsequent frequency dynamic trajectory based on the disturbance information extracted from the state-space model. It is not only applicable to online prediction but also addresses the shortcomings of traditional techniques in low-damped power grids, providing a reference for the operation of new energy power systems and ensuring the safe and stable operation of the system.

[0139] For better explanation, refer to Figure 2 This diagram illustrates the overall flow of a frequency dynamic trajectory prediction method provided by an embodiment of the present invention. It should be noted that this embodiment only provides a brief description of the general flow of frequency dynamic trajectory prediction. The specific implementation process of each step can be understood by referring to the relevant content in the foregoing embodiments, and will not be elaborated upon here. It is understood that the present invention does not impose any limitations on this.

[0140] Step 201: Considering the active power flow distribution and synchronous machine rotor motion in the power system, construct the state-space model of the primary frequency regulation of the power system;

[0141] Step 202: Construct the frequency dynamic trajectory model of the state-space model at the instant the disturbance occurs;

[0142] Step 203: Introduce a transformation matrix to transform the frequency dynamic trajectory model into an eigenvector model, which serves as the disturbance information extraction model at the moment the disturbance occurs;

[0143] Step 204: Based on the disturbance information extraction model, by introducing the difference matrix and solving for the disturbance location, the disturbance values ​​of the load at each time after the disturbance occurs are obtained;

[0144] Step 205: Integrate the various disturbance values ​​to construct the disturbance vector of the power system after the disturbance occurs;

[0145] Step 206: Substitute the disturbance vector into the frequency dynamic trajectory model, and perform frequency trajectory prediction calculation through the frequency dynamic trajectory model to obtain the frequency dynamic trajectory of the power system after the disturbance occurs.

[0146] To enable those skilled in the art to better understand the technical solutions of the present invention, the following specific example is used to illustrate the embodiments of the present invention.

[0147] This example validates the frequency dynamic trajectory prediction method in a modified IEEE 39-node system. The modified IEEE 39-node system network topology is as follows: Figure 3 As shown in the figure. Among them, offshore wind power is connected to the IEEE 39-bus system through a multi-terminal DC system.

[0148] Assuming a 300 MW load step occurs at bus 22, the simulation results and prediction results of the frequency response of some units are compared as follows: Figure 4 As shown. From Figure 4 As can be seen, the analytical curve and the simulated curve show good fit at key points such as the lowest frequency deviation and steady-state deviation. This fully verifies the feasibility and accuracy of the technical solution provided by the embodiments of the present invention.

[0149] Reference Figure 5 The diagram illustrates a structural block diagram of a frequency dynamic trajectory prediction device provided in an embodiment of the present invention, which may specifically include:

[0150] State space model building unit 501 is used to construct a state space model for primary frequency regulation of the power system, taking into account the active power flow distribution and synchronous machine rotor motion in the power system.

[0151] The disturbance information extraction model establishment unit 502 is used to establish a disturbance information extraction model at the instant of disturbance occurrence based on the state space model.

[0152] The disturbance vector solving unit 503 is used to extract the model based on the disturbance information and solve the disturbance vector of the power system after the disturbance occurs.

[0153] The frequency trajectory prediction unit 504 is used to combine the state space model and the disturbance vector to predict the frequency trajectory and obtain the dynamic frequency trajectory of the power system.

[0154] In one optional embodiment, the state-space model construction unit 501 includes:

[0155] The DC power flow model construction unit is used to construct a DC power flow model considering the active power flow distribution of the power system.

[0156] The model simplification unit is used to derive the electromagnetic power change vector of the synchronous machine in the power system and the output power change vector of the frequency-modulated asynchronous machine power supply based on the DC power flow model and through model simplification.

[0157] The synchronous machine model building unit is used to construct the synchronous machine rotor motion equation and the simplified speed governor model based on the key operating parameters of the synchronous machine in the power system.

[0158] The virtual synchronization control model construction unit is used to simultaneously consider the bus frequency offset, virtual inertia and virtual damping coefficient of the frequency-regulating asynchronous power supply in the power system to construct a virtual synchronization control model.

[0159] The state-space model construction subunit is used to construct the state-space model of the primary frequency regulation of the power system based on the DC power flow model, the electromagnetic power change vector, the output power change vector, the synchronous machine rotor motion equation, the speed governor simplified model, and the virtual synchronous control model.

[0160] In one optional embodiment, the DC power flow model construction unit is specifically used for:

[0161] Simultaneously considering the electromagnetic power change vector and power angle vector of the synchronous machine in the power system, the output power change vector and phase vector of the frequency-modulated asynchronous machine power supply, the load change vector and load bus vector, and combining the admittance block matrix, a DC power flow model is constructed.

[0162] In one optional embodiment, the key operating parameters include power angle, speed variation, mechanical power, electromagnetic power, rotor inertia time constant, damping coefficient, reheat time constant, droop coefficient, and high-pressure boiler ratio; the synchronous machine model construction unit includes:

[0163] The synchronous machine rotor motion equation construction unit is used to construct the synchronous machine rotor motion equation based on the power angle, the speed change, the mechanical power, the electromagnetic power, the rotor inertia time constant, and the damping coefficient.

[0164] The governor simplified model construction unit is used to construct a governor simplified model based on the reheat time constant, the droop coefficient and the proportion of high-pressure boiler.

[0165] In one optional embodiment, the disturbance information extraction model establishment unit 502 includes:

[0166] A frequency dynamic trajectory model construction unit is used to construct the frequency dynamic trajectory model of the state space model at the instant of the disturbance.

[0167] The eigenvector model construction unit is used to introduce a transformation matrix to transform the frequency dynamic trajectory model into an eigenvector model, which serves as a disturbance information extraction model at the moment of disturbance occurrence.

[0168] In one optional embodiment, the perturbation vector solving unit 503 includes:

[0169] The current system state substitution unit is used to obtain the current system state and substitute the current system state into the disturbance information extraction model;

[0170] The state variable change rate model acquisition unit is used to differentiate the disturbance information extraction model substituted with the current system state to obtain the state variable change rate model of the power system after the disturbance occurs; the state variable change rate model includes the disturbance vector to be solved;

[0171] The difference matrix equivalent model construction unit is used to construct an equivalent model of the difference matrix based on the disturbance vector to be solved, while considering the abrupt changes in the rate of change of rotational speed and frequency caused by the disturbance; the difference matrix is ​​introduced into the equivalent model of the difference matrix.

[0172] The measured rate of change mutation acquisition unit is used to acquire the measured rate of change mutation of the rotational speed and frequency of the power system at each moment after the disturbance occurs.

[0173] Angle calculation unit is used to calculate the angle between the measured rate of change mutation and each column vector in the difference matrix for each time moment.

[0174] The disturbance location determination unit is used to determine the vector position of the column vector with the smallest included angle in the difference matrix, and to determine the disturbance location based on the vector position;

[0175] The disturbance value solving unit is used to solve the disturbance value of the load at the disturbance location at the time based on the frequency change rate and moment of inertia of all synchronous and asynchronous power supplies in the power system at the time.

[0176] The disturbance vector construction unit is used to integrate the disturbance values ​​at various times after the disturbance occurs, and construct the disturbance vector of the power system after the disturbance occurs.

[0177] In one optional embodiment, the solution of the state-space model at the instant of the disturbance is represented as a frequency dynamic trajectory model; the frequency trajectory prediction unit 504 is specifically used for:

[0178] The disturbance vector is substituted into the frequency dynamic trajectory model, and the frequency trajectory prediction calculation is performed through the frequency dynamic trajectory model to obtain the frequency dynamic trajectory of the power system after the disturbance occurs.

[0179] As the device embodiment is basically similar to the method embodiment, it is described in a relatively simple way. For relevant details, please refer to the description of the method embodiment above.

[0180] This invention also provides an electronic device, which includes a processor and a memory:

[0181] The memory is used to store program code and transfer the program code to the processor;

[0182] The processor is used to execute the frequency dynamic trajectory prediction method of any embodiment of the present invention according to the instructions in the program code.

[0183] This invention also provides a computer-readable storage medium for storing program code for executing the frequency dynamic trajectory prediction method of any embodiment of this invention.

[0184] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0185] In the embodiments provided by this invention, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection between devices or units through some interfaces, and may be electrical, mechanical, or other forms.

[0186] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0187] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0188] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0189] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A frequency dynamic trajectory prediction method, characterized in that, include: Considering the active power flow distribution and synchronous machine rotor motion in the power system, a state-space model of the primary frequency regulation of the power system is constructed. Based on the state-space model, a disturbance information extraction model is established at the instant the disturbance occurs; Based on the disturbance information extraction model, the disturbance vector of the power system after the disturbance occurs is calculated; By combining the state-space model and the disturbance vector, frequency trajectory prediction is performed to obtain the dynamic frequency trajectory of the power system.

2. The frequency dynamic trajectory prediction method according to claim 1, characterized in that, The state-space model for primary frequency regulation of the power system, considering the active power flow distribution and synchronous machine rotor motion, includes: Considering the active power flow distribution of the power system, a DC power flow model is constructed; Based on the DC power flow model, the electromagnetic power change vector of the synchronous machine in the power system and the output power change vector of the frequency-modulated asynchronous machine power supply are derived through model simplification. Based on the key operating parameters of the synchronous machine in the power system, the synchronous machine rotor motion equation and the simplified model of the speed governor are constructed. Simultaneously considering the bus frequency offset, virtual inertia, and virtual damping coefficient of the frequency-regulating asynchronous power supply in the power system, a virtual synchronous control model is constructed. Based on the DC power flow model, the electromagnetic power change vector, the output power change vector, the synchronous machine rotor motion equation, the simplified speed governor model, and the virtual synchronous control model, a state-space model for the primary frequency regulation of the power system is constructed.

3. The frequency dynamic trajectory prediction method according to claim 2, characterized in that, The construction of a DC power flow model, considering the active power flow distribution of the power system, includes: Simultaneously considering the electromagnetic power change vector and power angle vector of the synchronous machine in the power system, the output power change vector and phase vector of the frequency-modulated asynchronous machine power supply, the load change vector and load bus vector, and combining the admittance block matrix, a DC power flow model is constructed.

4. The frequency dynamic trajectory prediction method according to claim 2, characterized in that, The key operating parameters include power angle, speed variation, mechanical power, electromagnetic power, rotor inertia time constant, damping coefficient, reheat time constant, droop coefficient, and the proportion of high-pressure boiler; the construction of the synchronous machine rotor motion equation and simplified speed governor model based on the key operating parameters of the synchronous machine in the power system includes: Based on the power angle, the change in rotational speed, the mechanical power, the electromagnetic power, the rotor inertia time constant, and the damping coefficient, the synchronous machine rotor motion equation is constructed. A simplified model of the governor is constructed based on the reheat time constant, the droop coefficient, and the proportion of high-pressure boiler.

5. The frequency dynamic trajectory prediction method according to claim 1, characterized in that, The step of establishing a disturbance information extraction model based on the state-space model at the instant of disturbance occurrence includes: Construct the frequency dynamic trajectory model of the state-space model at the instant the disturbance occurs; A transformation matrix is ​​introduced to transform the frequency dynamic trajectory model into a feature root vector model, which serves as a disturbance information extraction model at the moment the disturbance occurs.

6. The frequency dynamic trajectory prediction method according to claim 1, characterized in that, The step of solving the disturbance vector of the power system after a disturbance occurs based on the disturbance information extraction model includes: Obtain the current system state and substitute the current system state into the disturbance information extraction model; The disturbance information extraction model, which incorporates the current system state, is differentiated to obtain the state variable change rate model of the power system after the disturbance occurs; the state variable change rate model includes the disturbance vector to be solved. Based on the disturbance vector to be solved, and considering the abrupt changes in the rate of change of rotational speed and frequency caused by the disturbance, an equivalent model of the difference matrix is ​​constructed; the difference matrix is ​​introduced into the equivalent model of the difference matrix. Obtain the measured rate of change of the rotational speed and frequency of the power system at each moment after the disturbance occurs; For each time moment, calculate the angle between the measured rate of change mutation and each column vector in the difference matrix; Determine the position of the column vector with the smallest included angle in the difference matrix, and determine the perturbation position based on the vector position; Based on the frequency change rate and moment of inertia of all synchronous and asynchronous power supplies in the power system at the specified time, the disturbance value of the load at the disturbance location at the specified time is calculated. By integrating the disturbance values ​​at various times after the disturbance occurs, a disturbance vector of the power system after the disturbance occurs is constructed.

7. The frequency dynamic trajectory prediction method according to any one of claims 1 to 6, characterized in that, The solution of the state-space model at the instant of disturbance occurrence is represented as a frequency dynamic trajectory model; the step of combining the state-space model and the disturbance vector to predict the frequency trajectory and obtain the frequency dynamic trajectory of the power system includes: The disturbance vector is substituted into the frequency dynamic trajectory model, and the frequency trajectory prediction calculation is performed through the frequency dynamic trajectory model to obtain the frequency dynamic trajectory of the power system after the disturbance occurs.

8. A frequency dynamic trajectory prediction device, characterized in that, include: The state-space model building unit is used to construct the state-space model of the primary frequency regulation of the power system, taking into account the active power flow distribution and synchronous machine rotor motion in the power system. The disturbance information extraction model establishment unit is used to establish a disturbance information extraction model at the instant of disturbance occurrence based on the state space model. The disturbance vector solving unit is used to extract the model based on the disturbance information and solve the disturbance vector of the power system after the disturbance occurs. The frequency trajectory prediction unit is used to combine the state-space model and the disturbance vector to predict the frequency trajectory and obtain the dynamic frequency trajectory of the power system.

9. An electronic device, characterized in that, The device includes a processor and a memory: The memory is used to store program code and transmit the program code to the processor; The processor is used to execute the frequency dynamic trajectory prediction method according to any one of claims 1-7 according to the instructions in the program code.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium is used to store program code for executing the frequency dynamic trajectory prediction method according to any one of claims 1-7.

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