Power system load frequency control method considering disturbance compensation and related device

Abstract

The invention discloses a power system load frequency control method considering disturbance compensation and a related device, and belongs to the technical field of power system regulation and control. The method comprises the following steps: respectively carrying out frequency modulation characteristic analysis on a speed regulator, a prime mover and a generator-load of the power system, and establishing a subsystem nominal model of the multi-region interconnected power system; designing a disturbance observer to observe external unknown disturbance to obtain a disturbance estimation value, and further obtaining a subsystem load frequency control model containing disturbance compensation information; based on a distributed model prediction control strategy, a distributed model prediction controller considering disturbance compensation is designed according to the subsystem load frequency control model containing the disturbance compensation information; when a certain area in the interconnected power system is disturbed, the frequency deviation of each sub-area is adjusted to be zero through a distributed model prediction controller considering disturbance compensation, and it is ensured that power exchange between connecting lines in the sub-areas and the interconnected areas of the connecting lines is kept in a zero steady state.

Description

Technical Field

[0001] The invention belongs to the technical field of power system regulation and control, and relates to a power system load frequency control method considering disturbance compensation and a related device. Background Art

[0002] In recent years, with the continuous development of the power system, the power system has developed from a traditional single region to a cross-regional interconnection. The interconnected power system can achieve power mutual assistance and support between regions. When a power failure or power supply shortage occurs in a certain area, other areas can provide support through interconnection, thereby improving the power supply reliability and stability of the entire power system. However, this interconnected structure also makes the power system face a more complex operating environment and greater challenges.

[0003] Load frequency control of power systems is one of the key technologies to achieve stable operation of power systems and improve the reliability of power systems. With the continuous expansion of the scale of power systems and the increase in power exchange between regions, the frequency deviation between regions and the power deviation of tie lines have an increasingly significant impact on the operation of power systems. Therefore, the reasonable design and optimization of load frequency control strategies can effectively regulate the frequency and power exchange between regions, maintain the stable operation of power systems, and improve the safety and reliability of power systems. Stable power supply is the basis of various activities in modern society, and the continuous innovation and improvement of load frequency control technology will help reduce the failure rate and power outage rate of power systems, improve the stability and reliability of power supply, and provide strong support for social and economic development.

[0004] The load frequency control technology of multi-regional interconnected power systems is of great significance to energy security, stable operation of power systems, and social and economic development. Strengthening the research and application of load frequency control technology and continuously improving its technical level and application effect will help promote the development of power systems in a safe, efficient and sustainable direction, and promote the healthy development of the power industry and the sustainable development of social economy.

[0005] At present, distributed model predictive controllers are mostly used for load frequency control of power systems; however, the models for optimization and solution in existing distributed model predictive controllers mostly use the system nominal model, which does not fully consider the impact of disturbances on the power system, and only regards load changes as a disturbance that causes frequency deviation changes. Therefore, stable control only through distributed predictive controllers established by the nominal system will lead to a decrease in controller accuracy. In addition, some methods introduce load disturbances into the model as known quantities, but for real systems, external disturbances are generally unknown and constantly changing, and cannot be directly introduced into the model as a known quantity. Summary of the invention

[0006] The purpose of the present invention is to provide a power system load frequency control method and related devices considering disturbance compensation, so as to solve the technical problem in the prior art that the distributed model predictive controller is greatly affected by external unknown disturbances and it is difficult to accurately perform load frequency control.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions: In a first aspect, the present invention provides a method for controlling load frequency of a power system considering disturbance compensation, comprising the following steps: The frequency regulation characteristics of the power system's speed governor, prime mover and generator-load are analyzed respectively, and the influence of the power of the inter-regional tie line is considered in the generator-load link to establish a subsystem nominal model of the multi-regional interconnected power system; Based on the observer principle, a disturbance observer is designed to observe external unknown disturbances and obtain the disturbance estimation value; Introducing the disturbance estimation value into the subsystem nominal model to obtain a subsystem load frequency control model containing disturbance compensation information; Based on the distributed model predictive control strategy, a distributed model predictive controller considering disturbance compensation is designed according to the subsystem load frequency control model containing disturbance compensation information; When a disturbance occurs in a certain area of ​​the interconnected power system, the frequency deviation of each sub-area is adjusted to zero through the distributed model predictive controller considering disturbance compensation, and the power exchange between the interconnection line in the sub-area and its interconnected area is maintained in a zero steady state.

[0008] Furthermore, the frequency regulation characteristics of the speed regulator, prime mover and generator-load of the power system are analyzed respectively, and the influence of the power of the inter-regional tie line is considered in the generator-load link to establish the subsystem nominal model of the multi-regional interconnected power system, specifically including: According to the working principle of load frequency control of the power system, the frequency regulation characteristics of the speed governor, prime mover and generator-load are analyzed respectively, and a simplified model of the load frequency control system of the power system is established; the expression of the simplified model of the load frequency control system of the power system is:

[0009] in, is the system frequency deviation, for The first derivative of ; is the generator damping coefficient; is the generator moment of inertia; is the generator output power deviation, for The first derivative of ; The disturbance to the system; is the turbine time constant; is the change of the speed regulator valve, for The first derivative of ; is the feedback coefficient; is the speed regulator time constant; is the change in the reference set value; According to the simplified model of load frequency control system of power system, the influence of power of inter-regional interconnection line is considered in the generator-load link. By dynamically analyzing the power exchange model of interconnection line, the subsystem nominal model of multi-regional interconnected power system is established.

[0010] Furthermore, the subsystem nominal model of the multi-region interconnected power system is:

[0011] in, For sub-region The frequency deviation, for The first derivative of ; For sub-region Generator damping factor; For sub-region Generator moment of inertia; For sub-region Generator output power deviation, for The first derivative of ; For sub-region The tie line power deviation, for The first derivative of ; For sub-region the disturbance; For sub-region The turbine time constant, For sub-region Governor valve change, for The first derivative of ; For sub-region Feedback coefficient; For sub-region Governor time constant; For sub-region Reference set value change; For sub-region With neighbor sub-region The synchronization power factor between Neighbor sub-region Frequency deviation; For sub-region Regional control deviations; For sub-region The frequency deviation factor of The position limit constraints of the governor valve are:

[0012] in, For sub-region Reference setpoint change.

[0013] Furthermore, in the step of designing a disturbance observer based on the observer principle to observe the external unknown disturbance and obtain the disturbance estimate, the expression of the disturbance observer is:

[0014] in, is the internal state variable of the disturbance observer, for The first derivative of ; is the disturbance observer gain; For sub-region state variables; is the nominal model equation of the subsystem without disturbance; For sub-region Control input of Neighbor sub-region state variables; For sub-region An estimate of the amount of external disturbance.

[0015] Furthermore, the expression of the subsystem load frequency control model containing disturbance compensation information is:

[0016] Among them, the system matrix , , , and They are: , , , , ; in, is the state variable of the region, For sub-region The frequency deviation, For sub-region Generator output power deviation, For sub-region Governor valve change, For sub-region The tie line power deviation; is the control input; is the disturbance observation estimate of the disturbance observer; For sub-region Generator damping factor; For sub-region Generator moment of inertia; For sub-region Governor time constant; For sub-region Feedback coefficient; For sub-region With neighbor sub-region The synchronization power factor between For sub-region Feedback coefficient; For sub-region The turbine time constant; For sub-region Frequency deviation factor.

[0017] Furthermore, the distributed model predictive controller considering disturbance compensation is:

[0018]

[0019]

[0020]

[0021] System Matrix , , and They are: , , ,

[0022] in, Representing sub-region Control frequency; is the cost function; For the prediction time domain; is the disturbance compensation value observed by the disturbance observer; for Time sub-area Predict control inputs; for Time sub-area Predict state trajectories; for Moment Neighbor Sub-Region Predict state trajectories; For sub-region Generator moment of inertia; For sub-region Governor time constant; For sub-region Feedback coefficient; For sub-region With neighbor sub-region The synchronization power factor between For sub-region Feedback coefficient; For sub-region Generator damping factor; For sub-region The turbine time constant.

[0023] Furthermore, the cost function for:

[0024] in, and are weight matrices, and ; For the prediction time domain.

[0025] In a second aspect, the present invention provides a power system load frequency control system considering disturbance compensation, comprising: The nominal model building module is used to analyze the frequency regulation characteristics of the speed governor, prime mover and generator-load of the power system respectively, consider the influence of the power of the inter-regional tie line in the generator-load link, and establish the subsystem nominal model of the multi-regional interconnected power system; The disturbance observation module is used to design a disturbance observer based on the observer principle to observe external unknown disturbances and obtain the disturbance estimation value; A disturbance compensation module, used for introducing the disturbance estimation value into the subsystem nominal model to obtain a subsystem load frequency control model containing disturbance compensation information; A predictive controller design module, used for designing a distributed model predictive controller taking disturbance compensation into consideration based on a distributed model predictive control strategy and according to the subsystem load frequency control model containing disturbance compensation information; The regulation module is used to adjust the frequency deviation of each sub-area to zero through the distributed model predictive controller considering disturbance compensation when a disturbance occurs in a certain area in the interconnected power system, and ensure that the power exchange between the interconnection line in the sub-area and its interconnected area is maintained in a zero steady state.

[0026] In a third aspect, the present invention provides a computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of a method for load frequency control of an electric power system taking into account disturbance compensation when executing the computer program.

[0027] In a fourth aspect, the present invention provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of a method for load frequency control of an electric power system taking into account disturbance compensation.

[0028] Compared with the prior art, the present invention has the following beneficial effects: The present invention discloses a method and related device for load frequency control of a power system considering disturbance compensation. By respectively analyzing the frequency regulation characteristics of the speed regulator, prime mover and generator-load of the power system in detail, and especially considering the influence of the power of the regional tie line in the generator-load link, the present invention establishes a more accurate subsystem nominal model of a multi-region interconnected power system. The subsystem nominal model of a multi-region interconnected power system can more comprehensively reflect the dynamic characteristics of the system, and provides a solid foundation for the design of subsequent control strategies. Combined with the design of the disturbance observer, it can observe and estimate external unknown disturbances in real time, and then introduce disturbance compensation information into the subsystem nominal model, effectively suppressing the influence of the disturbance on the frequency stability of the system, and significantly improving the stability and robustness of the power system. And through the subsystem load frequency control model containing disturbance compensation information, a distributed model predictive controller considering disturbance compensation is designed, which can make full use of the local information of each sub-region and realize global coordinated control, so as to more quickly and accurately adjust the frequency deviation of each sub-region to zero, and improve the accuracy and response speed of load frequency control. The present invention can handle both complex objective functions and various complex constraints, and can effectively overcome the problems of uncertainty and nonlinearity in the power system. Therefore, it is particularly suitable for multi-region interconnected power systems with nonlinearity, strong coupling, constraints and uncertainties. Distributed model predictive control has the advantages of high reliability, flexibility, and fast solution, and is very suitable for the control of multi-coupled, geographically dispersed, high-dimensional dynamic complex power systems. The present invention uses the droop control principle to achieve the goal of quickly eliminating frequency deviations while adjusting the system frequency to stabilize while satisfying the actual operating constraints of each sub-region. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0030] Figure 1 is a flow chart of the method of the present invention; Figure 2 is a schematic diagram of the system of the present invention; Figure 3 A flow chart of a distributed predictive control strategy for adjusting load frequency taking disturbance compensation into consideration according to an embodiment of the present invention; Figure 4 This is a load frequency control structure diagram of a regional interconnected power system according to a third embodiment of the present invention; Figure 5 A structural diagram of a distributed predictive control strategy taking disturbance compensation into account according to an embodiment of the present invention; Figure 6 This is an observation curve diagram of the disturbance observer for the step load disturbance of sub-area 2 according to an embodiment of the present invention; FIG7 (a) is a frequency deviation response curve of a subsystem according to an embodiment of the present invention, FIG7 (b) is a regional control deviation response curve according to an embodiment of the present invention, FIG7 (c) is an input response curve of a power system according to an embodiment of the present invention, and FIG7 (d) is a tie-line power response curve according to an embodiment of the present invention; Figure 8 It is a schematic diagram of the computer device structure of the present invention. DETAILED DESCRIPTION

[0031] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments. It should be noted that the embodiments and features in the embodiments of the present application can be combined with each other without conflict.

[0032] The following detailed description is an exemplary description, which is intended to provide further detailed description of the present invention. Unless otherwise specified, all technical terms used in the present invention have the same meaning as those generally understood by those skilled in the art to which the present application belongs. The terms used in the present invention are only for describing specific embodiments, and are not intended to limit exemplary embodiments according to the present invention.

[0033] The present invention is further described in detail below in conjunction with the accompanying drawings: See also Figure 1 The embodiment of the present invention discloses a method for controlling the load frequency of a power system considering disturbance compensation, comprising the following steps: S1, analyze the frequency regulation characteristics of the speed governor, prime mover and generator-load of the power system respectively, and consider the influence of the power of the inter-regional tie line in the generator-load link to establish the subsystem nominal model of the multi-regional interconnected power system; S101, according to the working principle of power system load frequency control, the frequency regulation characteristics of several components such as speed governor, prime mover, generator-load are analyzed respectively, and the simplified model of power system load frequency control system is established as follows: (1) in, is the system frequency deviation, for The first derivative of ; is the generator damping coefficient; is the generator moment of inertia; is the generator output power deviation, for The first derivative of ; The disturbance to the system; is the turbine time constant; is the change of the speed regulator valve, for The first derivative of ; is the feedback coefficient; is the speed regulator time constant; is the change in the reference set value.

[0034] S102, based on the simplified model of the load frequency control system of the power system, considering the influence of the power of the inter-regional tie line in the generator-load link, and establishing a subsystem nominal model of the multi-regional interconnected power system by dynamically analyzing the tie line power exchange model; Consider a A multi-area interconnected system consisting of 3 control areas, the power deviation of the interconnection line It can be expressed as: (2) in, For sub-region With neighbor sub-region The synchronous power factor, Neighbor sub-region Frequency deviation; For sub-region frequency deviation.

[0035] The mathematical model of the generator-load link considering the influence of the inter-regional tie line power is: (3) It can be seen that when a disturbance occurs in a certain area of ​​the interconnected power system, the frequency of the interconnected subsystem will also deviate due to the influence of the tie line. Therefore, it is necessary to calculate the frequency deviation of each area. Adjust to zero, and exchange power with the interconnected areas through the interconnection lines in the current area to ensure the interconnection line power deviation between areas Maintain in zero steady state. The system output is composed of frequency deviation and tie line power deviation, which is called regional control deviation. . It is expressed as: (4) in, For sub-region The regional control deviation, For sub-region The frequency deviation factor.

[0036] The subsystem nominal model of the multi-regional interconnected power system is: (5) in, For sub-region The frequency deviation, for The first derivative of ; For sub-region Generator damping factor; For sub-region Generator moment of inertia; For sub-region Generator output power deviation, for The first derivative of ; For sub-region The tie line power deviation, for The first derivative of ; For sub-region the disturbance; For sub-region The turbine time constant, For sub-region Governor valve change, for The first derivative of ; For sub-region Feedback coefficient; For sub-region Governor time constant; For sub-region Reference set value change; For sub-region With neighbor sub-region The synchronization power factor between Neighbor sub-region Frequency deviation; For sub-region Regional control deviations; For sub-region The frequency deviation factor.

[0037] In addition, due to mechanical limitations, the valve position cannot be changed outside a certain range. Therefore, the governor valve position limitation should be considered in actual control, and the corresponding control input constraint can be expressed as: (6) in, For sub-region Reference setpoint change.

[0038] S2, based on the observer principle, a disturbance observer is designed to observe external unknown disturbances and obtain the disturbance estimate; Considering the impact of external unknown disturbances on the system in the actual environment, based on the observer principle, a disturbance observer is designed to observe the external unknown disturbances. The disturbance observer is used to estimate the disturbance in the system, and the dynamic model of the disturbance observer can be expressed as: (7) in, is the internal state variable of the disturbance observer, for The first derivative of ; is the disturbance observer gain; For sub-region state variables; is the nominal model equation of the subsystem without disturbance; For sub-region Control input of Neighbor sub-region state variables; For sub-region The estimated value of the external disturbance. The estimated error of the disturbance can be expressed as: (8) Assuming that in the actual process, the disturbance The change of is slower than the change of the system state. The time derivative of is 0. The dynamics of the disturbance estimation error can be expressed as: (9) The above formula shows that by properly choosing the disturbance observer function , which can ensure the asymptotic stability of the system and thus realize the effective observation of unknown disturbances in the system.

[0039] S3, introducing the disturbance estimation value into the subsystem nominal model to obtain a subsystem load frequency control model containing disturbance compensation information; The disturbance estimation value observed by the observer is introduced into the subsystem nominal model to compensate for the influence of external unknown disturbance on the system in the real environment, and a subsystem load frequency control model containing disturbance compensation information is established. The load frequency control model of each sub-area can be expressed as: (10) in, is the state variable of the region, is the control input, is the disturbance observation estimate of the disturbance observer. Among them, the system matrix , , , and They are: , , , , .

[0040] in, For sub-region Generator damping factor; For sub-region Generator moment of inertia; For sub-region Governor time constant; For sub-region Feedback coefficient; For sub-region With neighbor sub-region The synchronization power factor between For sub-region Feedback coefficient; For sub-region The turbine time constant; For sub-region Frequency Deviation Factor S4, based on a distributed model predictive control strategy, designing a distributed model predictive controller taking disturbance compensation into consideration according to the subsystem load frequency control model containing disturbance compensation information; According to the subsystem load frequency control model containing disturbance information established by S3, a distributed model predictive control controller (Disturbance compensation distributed model prediction control, DC-DMPC) is designed based on the distributed model predictive control strategy.

[0041] The distributed model predictive controller considering disturbance compensation is: (11) (12a) (12b) (12c) Cost Function Designed for: (13) in, and are weight matrices, and , represents the prediction time domain, Representing sub-region Control frequency; is the cost function; For the prediction time domain; is the disturbance compensation value observed by the disturbance observer; for Time sub-area Predict control inputs; for Time sub-area Predict state trajectories; for Moment Neighbor Sub-Region Predict state trajectories; For sub-region Generator moment of inertia; For sub-region Governor time constant; For sub-region Feedback coefficient; For sub-region With neighbor sub-region The synchronization power factor between For sub-region Feedback coefficient; For sub-region Generator damping factor; For sub-region The turbine time constant, formula (12a) is the LFC (Load Frequency Control) dynamic model with disturbance compensation information that satisfies formula (10), and formula (12b) is the time constant of the steam turbine. is the real state of the system, and formula (12c) is the control quantity constraint.

[0042] S5, when a disturbance occurs in a certain area of ​​the interconnected power system, the frequency deviation of each sub-area is adjusted to zero through the distributed model predictive controller considering disturbance compensation, and the power exchange between the interconnection line in the sub-area and its interconnected area is ensured to be maintained in a zero steady state.

[0043] The controller designed by S4 is used for load frequency control. When a disturbance occurs in a certain area of ​​the interconnected power system, the distributed controller of each sub-area adjusts the frequency deviation of its area to zero and ensures that the power exchange between the tie line in the current area and the area it is interconnected with is maintained in a zero steady state.

[0044] Among many control strategies, model predictive control can handle both complex objective functions and various complex constraints, and can effectively overcome the uncertainty and nonlinearity in the system. Therefore, it is particularly suitable for multi-regional interconnected power systems with nonlinearity, strong coupling, constraints and uncertainties. With the continuous expansion and interconnection of power systems, distributed model predictive control has the advantages of high reliability, flexibility, fast solution, etc., and can coordinate multiple local controllers to achieve global optimization or Nash optimization. It is very suitable for the control of multi-coupled, geographically dispersed, high-dimensional dynamic complex power systems.

[0045] In the load frequency control problem in the multi-region interconnected power system, the goal is to design a local DC-DMPC controller for each sub-region, and quickly stabilize the system frequency deviation and interconnection power deviation to zero under the premise of satisfying the control constraints. In actual control, in order to protect the power generation unit, it is expected that the control action of the valve will not change too much. Considering the above goals, for the sub-region , cost function The weight matrix and The values ​​of are , . Sampling time , prediction time domain At the same time, in order to ensure the optimization problem At the initial moment It is feasible to set the initial states of the three sub-areas to The present invention utilizes the nonlinear optimization function in the MATLAB optimization tool Solve the optimization problem online and obtain the control quantity at the current moment.

[0046] Load frequency control is the core of power grid frequency regulation technology. Its basic task is to adjust the power supply frequency of the power system and keep it at the reference value (50Hz) to ensure the power supply quality and the safe, reliable and economical operation of the power system. When the load of the power system changes suddenly, the frequency of the power system will inevitably deviate. The sensor measures this deviation and feeds it back to the controller. Through the droop control principle, the system frequency can be adjusted to be stable while meeting the actual operating constraints of each sub-area, so as to achieve the goal of quickly eliminating frequency deviation. Based on the observer principle, the present invention adopts a disturbance observer to observe external unknown disturbances, introduces disturbance estimates into the subsystem nominal model to compensate for the errors caused by disturbances and various uncertainties, improve the prediction accuracy of the controller, reduce the calculation time of the controller to solve the optimization problem, and finally obtain the required offset-free tracking performance.

[0047] Example: See also Figure 3 This embodiment discloses a method for controlling the load frequency of a power system considering disturbance compensation. The multi-region interconnected power system is a thermal power generating unit comprising three interconnected regions. Each thermal power generating unit is composed of a speed governor, a non-reheat steam turbine and a generator-load model. The load frequency control structure diagram of the three-region interconnected power system is shown in the attached figure. Figure 4 As shown, the controller in the figure adopts the control strategy proposed by the present invention. In addition, all three sub-areas may be disturbed by external loads. and due to the randomness of the external environment, external load disturbance Often unknown and changing.

[0048] The method of the present invention is used to simulate the three-region interconnected power system in this embodiment, and the simulation environment is MATLAB R2022b. The parameters of the three-region interconnected power system are shown in Table 1: Table 1 Parameters of generator sets in the three-region interconnected power system

[0049] Based on the above scheme, the structural block diagram of the distributed model prediction strategy considering disturbance compensation proposed by the present invention is shown in the attached figure. Figure 5 The disturbance observer observes the external unknown disturbances to the system in the real environment and estimates the disturbance Introduce the subsystem nominal model to establish the DC-DMPC (Direct Current-Dynamic Matrix Predictive Control) optimization problem. This improves the prediction accuracy and obtains more accurate control quantity. .

[0050] In order to evaluate the anti-disturbance performance of the sub-area under the control of the method of the present invention under load disturbance, it is assumed that the sub-area 2 is subjected to an external variable step load disturbance, and the change of the step load disturbance is as follows: (14) Attached Figure 6 The disturbance observer is shown to be able to detect the random load disturbance in sub-area 2. The solid line in the figure is the actual disturbance change curve, and the dotted line is the disturbance observer's estimate of the disturbance. The results show that when the external load When a sudden change occurs, the disturbance observer can complete the tracking and estimation of the changed disturbance value within 5 seconds, indicating that the disturbance observer can quickly track and stabilize near the changed value, verifying the effectiveness of the tracking performance of the designed disturbance observer.

[0051] Figures 7 (a), 7 (b), 7 (c) and 7 (d) show the response curves of the sub-regions under the DC-DMPC strategy of the method of the present invention. For comparison, under the same parameter setting conditions, the system response results under the action of the DMPC controller are also given. Among them, Figure 7 (a) is the frequency deviation response curve of the subsystem; Figure 7 (b) is the regional control deviation response curve; Figure 7 (c) is the input response curve of the power system; Figure 7 (d) is the interconnection line power response curve. Through the analysis of the simulation results, it can be seen that when the external load disturbance in sub-region 2 When there is a change, due to the influence of the multi-regional interconnected power system, the system states of sub-regions 1 and 3 will also change. Analysis of Figure 7(a) and Figure 7(d) shows that under the control of the DC-DMPC strategy, the multi-regional interconnected power system can reduce the frequency deviation to and tie line power deviation Drive to zero while satisfying the input constraints. However, the system under the DMPC strategy without considering disturbance compensation has errors, and the errors increase with the increase of disturbances. As shown in Figure 7(c), the generator power is constantly adjusted and changed with the external load disturbance and stabilized near the load change value, which indicates that the imbalance between supply and demand caused by the load disturbance has been compensated by the output power of the unit. In order to further reflect the effectiveness of the method of the present invention, Table 2 summarizes the total CPU calculation time of the two methods under the same simulation time.

[0052] Table 2 The corresponding CPU running time under the two strategies

[0053] From the analysis of Table 2, we can see that by properly designing the disturbance observer gain , and introduce the disturbance estimation value into the subsystem nominal model for compensation, which can significantly improve the prediction accuracy of DMPC, make the control quantity more accurate, and effectively reduce the calculation time. Specifically, after adopting the DC-DMPC strategy, the total CPU (Central Processing Unit) calculation time is only 58.48% of the DMPC strategy, which effectively reduces the calculation time and improves the calculation efficiency. This result verifies the effectiveness of disturbance compensation in improving prediction accuracy and reducing CPU calculation time in the subsystem nominal model.

[0054] See also Figure 2 , an embodiment of the present invention discloses a power system load frequency control system considering disturbance compensation, including a nominal model building module, a disturbance observation module, a disturbance compensation module and a predictive controller design module; Among them, the nominal model establishment module is used to analyze the frequency regulation characteristics of the speed regulator, prime mover and generator-load of the power system respectively, consider the influence of the power of the inter-regional interconnection line in the generator-load link, and establish the subsystem nominal model of the multi-region interconnected power system; the disturbance observation module is used to design a disturbance observer based on the observer principle to observe the external unknown disturbance and obtain the disturbance estimation value; the disturbance compensation module is used to introduce the disturbance estimation value into the subsystem nominal model to obtain the subsystem load frequency control model containing disturbance compensation information; the predictive controller design module is used to design a distributed model predictive controller considering disturbance compensation based on the distributed model predictive control strategy according to the subsystem load frequency control model containing disturbance compensation information; the adjustment module is used to adjust the frequency deviation of each sub-region to zero through the distributed model predictive controller considering disturbance compensation when a disturbance occurs in a certain area of ​​the interconnected power system, and ensure that the power exchange between the interconnection line in the sub-region and its interconnected area is maintained in a zero steady state.

[0055] In one embodiment of the present invention, see Figure 8, a computer device is provided, the computer device includes a processor and a memory, the memory is used to store a computer program, the computer program includes program instructions, and the processor is used to execute the program instructions stored in the computer storage medium. The processor may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc. It is the computing core and control core of the terminal, which is suitable for implementing one or more instructions, and is specifically suitable for loading and executing one or more instructions in the computer storage medium to implement the corresponding method flow or corresponding function; the processor described in the embodiment of the present invention can be used for the operation of the power system load frequency control method considering disturbance compensation.

[0056] The present invention also provides a storage medium, specifically a computer-readable storage medium (Memory), which is a memory device in a computer device for storing programs and data. It is understandable that the computer-readable storage medium here can include both built-in storage media in the computer device and, of course, extended storage media supported by the computer device. The computer-readable storage medium provides a storage space, which stores the operating system of the terminal. In addition, one or more instructions suitable for being loaded and executed by the processor are also stored in the storage space, and these instructions can be one or more computer programs (including program codes). It should be noted that the computer-readable storage medium here can be a high-speed RAM memory or a non-volatile memory (non-volatile memory), such as at least one disk memory. The processor can load and execute one or more instructions stored in the computer-readable storage medium to implement the corresponding steps of the power system load frequency control method considering disturbance compensation in the above embodiment.

[0057] It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0058] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0059] These computer program instructions may also be stored in a computer readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture including an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0060] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process in the computer or other programmable device. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for controlling power system load frequency considering disturbance compensation, characterized in that: The following steps are involved: The frequency regulation characteristics of the power system's speed governor, prime mover and generator-load are analyzed respectively, and the influence of the power of the inter-regional tie line is considered in the generator-load link to establish a subsystem nominal model of the multi-regional interconnected power system; Based on the observer principle, a disturbance observer is designed to observe external unknown disturbances and obtain the disturbance estimation value; Introducing the disturbance estimation value into the subsystem nominal model to obtain a subsystem load frequency control model containing disturbance compensation information; Based on the distributed model predictive control strategy, a distributed model predictive controller considering disturbance compensation is designed according to the subsystem load frequency control model containing disturbance compensation information; When a disturbance occurs in a certain area of ​​the interconnected power system, the frequency deviation of each sub-area is adjusted to zero through the distributed model predictive controller considering disturbance compensation, and the power exchange between the tie line in the sub-area and its interconnected area is maintained in a zero steady state.

2. A method for controlling power system load frequency considering disturbance compensation according to claim 1, characterized in that: The steps of analyzing the frequency regulation characteristics of the speed regulator, prime mover and generator-load of the power system respectively, and considering the influence of the power of the inter-regional tie line in the generator-load link to establish the subsystem nominal model of the multi-regional interconnected power system specifically include: According to the working principle of load frequency control of the power system, the frequency regulation characteristics of the speed governor, prime mover and generator-load are analyzed respectively, and a simplified model of the load frequency control system of the power system is established; the expression of the simplified model of the load frequency control system of the power system is: in, is the system frequency deviation, for The first derivative of ; is the generator damping coefficient; is the generator moment of inertia; is the generator output power deviation, for The first derivative of ; The disturbance to the system; is the turbine time constant; is the change of the speed regulator valve, for The first derivative of ; is the feedback coefficient; is the speed regulator time constant; is the change in the reference set value; According to the simplified model of load frequency control system of power system, the influence of power of inter-regional interconnection line is considered in the generator-load link. By dynamically analyzing the power exchange model of interconnection line, the subsystem nominal model of multi-regional interconnected power system is established.

3. A method for controlling power system load frequency considering disturbance compensation according to claim 2, characterized in that: The subsystem nominal model of the multi-regional interconnected power system is: in, For sub-region The frequency deviation, for The first derivative of ; For sub-region Generator damping factor; For sub-region Generator moment of inertia; For sub-region Generator output power deviation, for The first derivative of ; For sub-region The tie line power deviation, for The first derivative of ; For sub-region the disturbance; For sub-region The turbine time constant, For sub-region Governor valve change, for The first derivative of ; For sub-region Feedback coefficient; For sub-region Governor time constant; For sub-region Reference set value change; For sub-region With neighbor sub-region The synchronization power factor between Neighbor sub-region Frequency deviation; For sub-region Regional control deviations; For sub-region The frequency deviation factor of The position limit constraints of the governor valve are: in, For sub-region Reference setpoint change.

4. The method for controlling power system load frequency considering disturbance compensation according to claim 1, characterized in that: In the step of designing a disturbance observer based on the observer principle to observe the external unknown disturbance and obtain the disturbance estimation value, the expression of the disturbance observer is: in, is the internal state variable of the disturbance observer, for The first derivative of ; is the disturbance observer gain; For sub-region state variables; is the nominal model equation of the subsystem without disturbance; For sub-region Control input of Neighbor sub-region state variables; For sub-region An estimate of the amount of external disturbance.

5. The method for controlling power system load frequency considering disturbance compensation according to claim 1, characterized in that: The expression of the subsystem load frequency control model containing disturbance compensation information is: Among them, the system matrix , , , and They are: ， ， ， ， ； in, is the state variable of the region, For sub-region The frequency deviation, For sub-region Generator output power deviation, For sub-region Governor valve change, For sub-region The tie line power deviation; is the control input; is the disturbance observation estimate of the disturbance observer; For sub-region Generator damping factor; For sub-region Generator moment of inertia; For sub-region Governor time constant; For sub-region Feedback coefficient; For sub-region With neighbor sub-region The synchronization power factor between For sub-region Feedback coefficient; For sub-region The turbine time constant; For sub-region Frequency deviation factor.

6. A method for controlling power system load frequency considering disturbance compensation according to claim 5, characterized in that: The distributed model predictive controller considering disturbance compensation is: System Matrix , , and They are: ， ， ， in, Representing sub-region Control frequency; is the cost function; For the prediction time domain; is the disturbance compensation value observed by the disturbance observer; for Time sub-area Predict control inputs; for Time sub-area Predict state trajectories; for Moment Neighbor Sub-Region Predict state trajectories; For sub-region Generator moment of inertia; For sub-region Governor time constant; For sub-region Feedback coefficient; For sub-region With neighbor sub-region The synchronization power factor between For sub-region Feedback coefficient; For sub-region Generator damping factor; For sub-region The turbine time constant.

7. A method for controlling power system load frequency considering disturbance compensation according to claim 6, characterized in that: The cost function for: in, and are weight matrices, and ; For the prediction time domain.

8. A power system load frequency control system considering disturbance compensation, characterized in that: include: The nominal model building module is used to analyze the frequency regulation characteristics of the speed governor, prime mover and generator-load of the power system respectively, consider the influence of the power of the inter-regional tie line in the generator-load link, and establish the subsystem nominal model of the multi-regional interconnected power system; The disturbance observation module is used to design a disturbance observer based on the observer principle to observe external unknown disturbances and obtain the disturbance estimation value; A disturbance compensation module, used for introducing the disturbance estimation value into the subsystem nominal model to obtain a subsystem load frequency control model containing disturbance compensation information; A predictive controller design module, used for designing a distributed model predictive controller taking disturbance compensation into consideration based on a distributed model predictive control strategy and according to the subsystem load frequency control model containing disturbance compensation information; The regulation module is used to adjust the frequency deviation of each sub-area to zero through the distributed model predictive controller considering disturbance compensation when a disturbance occurs in a certain area in the interconnected power system, and ensure that the power exchange between the interconnection line in the sub-area and its interconnected area is maintained in a zero steady state.

9. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the method for controlling load frequency of a power system taking disturbance compensation into consideration as described in any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of a method for controlling load frequency of a power system taking disturbance compensation into consideration as described in any one of claims 1 to 7 are implemented.

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