Wide-area power grid secondary frequency modulation control method and system based on bidirectional adaptive event triggering and dynamic boundary layer sliding mode

Abstract

The present application relates to the technical field of automatic control of power system, and specifically discloses a wide-area power grid secondary frequency modulation control method and system based on bidirectional adaptive event triggering and dynamic boundary layer sliding mode, comprising: obtaining real-time operation parameters of each frequency modulation resource in the wide-area power grid; constructing an open-loop secondary frequency modulation dynamic model based on the above parameters; dynamically adjusting the triggering threshold according to the system state and establishing an event triggering judgment rule; combining the physical ramp rate constraint to construct a closed-loop nonlinear frequency modulation model; introducing a dynamic sliding mode boundary layer mechanism controlled by the real-time frequency deviation; analyzing the robust stability and anti-interference performance of the system based on Lyapunov stability theory, and solving the optimal closed-loop control parameters; real-time acquisition of the wide-area power grid regional control deviation, intelligent issuance and update of the secondary frequency modulation power control instruction. The present application improves the frequency stability of the wide-area power grid, reduces the control frequency and communication load, prolongs the service life of the equipment, and adapts to the high penetration rate of new energy scenarios.

Description

Technical Field

[0001] This invention relates to the field of power system automatic control technology, and in particular to a wide-area power grid secondary frequency regulation control method and system based on bidirectional adaptive event triggering and dynamic boundary layer sliding mode. Background Technology

[0002] With the large-scale integration of renewable energy sources with high penetration rates, modern wide-area power grids exhibit significant characteristics of low inertia and strong stochasticity. Due to the large spatial span and diverse active power regulation resources within wide-area power grids, the frequency stability of the system is highly dependent on the coordinated response of various frequency regulation resources (such as synchronous generators, controllable load energy storage devices, and energy storage batteries). When the region experiences severe load fluctuations or sudden changes in renewable energy output, frequency deviations caused by multi-source power imbalances are easily amplified and widely propagated, seriously affecting power quality and the safety and stability of the power grid. Therefore, coordinated secondary frequency regulation control oriented towards multiple controllable resources has become a key and critical issue that urgently needs to be addressed for the safe and stable operation of modern wide-area power grids.

[0003] Traditional secondary frequency modulation (DFFM) often employs periodic control strategies. Frequent command updates not only increase the burden on wide-area communication but also easily lead to frequent switching and starting / stopping of physical DFFM equipment, shortening equipment lifespan and resulting in low resource utilization. To address this, Event-Triggered Control (ETC) has been introduced into secondary DFFM to reduce control frequency. However, existing triggering methods often rely on fixed thresholds or unidirectional adjustment mechanisms that reset instantaneously when errors increase. These mechanisms cannot flexibly adapt to the bidirectional evolution of frequency deviations, easily leading to control response lag or excessive command redundancy, making it difficult to guarantee the economic efficiency of system operation.

[0004] On the other hand, controllable load energy storage devices (such as electrohydrogen generation devices) are becoming a promising emerging frequency regulation resource in wide-area power grids due to their wide regulation range and fast power response. However, when such controllable loads participate in secondary frequency regulation, their operation is inevitably limited by physical constraints such as power ramp-up rate, switching frequency, and safety thresholds. If the frequency regulation strategy ignores these nonlinear constraints, it can easily lead to accelerated equipment aging, exceeding operational limits, or even frequency regulation failure. In addition, wide-area power grids constantly face complex uncertainties such as strong external power disturbances from multiple sources and cross-regional communication delays. Traditional linear control methods are significantly insufficient in terms of system stability and anti-interference robustness when dealing with such multiple constraints and complex operating conditions.

[0005] In secondary frequency regulation of wide-area power grids, sliding mode control is widely used due to its strong robustness. However, its inherent switching characteristics can cause high-frequency chattering, which severely exacerbates the physical losses of actuators such as controllable loads and energy storage. To suppress chattering, traditional methods often introduce a sliding mode boundary layer of fixed thickness. However, this leads to a dilemma: if the boundary layer is too large, it reduces steady-state accuracy; if it is too small, it is difficult to suppress chattering.

[0006] Therefore, there is an urgent need for a novel secondary frequency regulation method that comprehensively considers event triggering mechanisms, the robustness of sliding mode control, the physical characteristics of electric hydrogen production devices, and the chattering problem introduced by sliding mode control, in order to improve the frequency stability and control efficiency of isolated wide-area power grids under complex operating environments. Summary of the Invention

[0007] To address the aforementioned problems in the prior art, this invention provides a method for secondary frequency regulation of controllable loads in wide-area power grids based on bidirectional adaptive event triggering and dynamic boundary layer sliding mode. This method solves the problems of heavy communication burden, risk due to neglect of equipment constraints, weak anti-interference capability, and chattering caused by traditional control.

[0008] To achieve the above objectives, this invention provides a wide-area power grid secondary frequency regulation control method based on bidirectional adaptive event triggering and dynamic boundary layer sliding mode, comprising the following steps: S1. Obtain the operating parameters of the wide area power grid and the operating parameters of the equipment participating in secondary frequency regulation, wherein the equipment includes a controllable load type energy storage device, a synchronous generator and an energy storage battery; S2. Based on the operating parameters of the wide area power grid and the operating parameters of the equipment, construct a dynamic model for open-loop secondary frequency regulation of the wide area power grid; S3. Construct an integral sliding surface containing wide-area power grid state variables and integral terms, and derive the equivalent sliding controller. S4. Design a bidirectional adaptive event triggering mechanism to generate event triggering thresholds that are smoothly and gradually adjusted in both directions as the state deviation of the wide-area power grid system increases or decreases; based on the event triggering thresholds, construct event triggering determination rules for determining whether the state data of the wide-area power grid system needs to be transmitted. S5. Combining the open-loop secondary frequency regulation dynamic model with the physical power ramp-up rate constraints of the controllable load energy storage device, synchronous generator, and energy storage battery, construct a closed-loop secondary frequency regulation system model considering nonlinear saturation truncation constraints. S6. Stability analysis of wide-area power grid systems based on Lyapunov-Krasovskii functional analysis and To improve anti-interference performance, a first set of matrix inequalities containing controller gain and event triggering parameters is constructed. The linear matrix inequalities are linearized using the congruent transformation technique to obtain a linear set of matrix inequalities. Solving the linear set of matrix inequalities yields the controller feedback gain and event triggering weight matrix parameters. S7. Design an event-triggered secondary frequency modulation sliding mode control law and introduce a dynamic sliding mode boundary layer that adaptively scales with the real-time frequency deviation. S8. Real-time acquisition of wide-area power grid frequency deviation, and issuance of secondary frequency regulation power control command by driving sliding mode control law according to the event triggering judgment rule; when the frequency deviation increases, the dynamic sliding mode boundary layer adaptively expands to suppress high-frequency chattering of the system; when the frequency deviation decreases, the dynamic sliding mode boundary layer adaptively contracts to improve the steady-state control accuracy of secondary frequency regulation.

[0009] Preferably, in step S2, the step of constructing the open-loop secondary frequency regulation dynamic model of the wide-area power grid includes: S21. Select the electric hydrogen production device as a controllable load type energy storage device, and construct it as a first-order inertial frequency-power response model to obtain the frequency-active power response model of the electric hydrogen production device. S22. Construct a dynamic characteristic model of a synchronous generator, including a governor dynamic characteristic model and a turbine dynamic characteristic model; S23. Construct a linear regulation model for energy storage batteries; S24. Combine the frequency-active power response model of the electric hydrogen production device, the dynamic characteristic model of the synchronous generator, the linear regulation model of the energy storage battery, and the frequency deviation feedback relationship in the operating parameters of the wide area power grid. Use the frequency regulation participation condition to construct the control command allocation relationship of the wide area power grid and establish an open-loop secondary frequency regulation dynamic model of the wide area power grid.

[0010] Preferably, in S24, the expression for the frequency modulation participation condition is: ; In the formula, This is the reference output active power adjustment for the synchronous generator. This is the adjustment amount for the reference output active power of the energy storage battery. This is the reference hydrogen production power adjustment amount for the electro-hydrogen production equipment; , and For frequency modulation participation factor, , This is a secondary frequency modulation command.

[0011] Preferably, in S4, the event triggering threshold is adjusted through the following bilateral dynamic update mechanism: ; ; In the formula, for The event trigger threshold at any given time. for The frequency deviation of the wide-area power grid load at any given time; , , , ; This is the minimum trigger threshold value; This is the maximum trigger threshold. These are bilateral adaptive parameters.

[0012] Preferably, in S5, the physical power ramp rate constraint includes: Ramp-up constraints for electro-hydrogen production units: ; In the formula, The maximum active power adjustment rate limit for the electro-hydrogen production unit; Synchronous generator ramping constraints: ; In the formula, This is the maximum active power regulation rate limit for synchronous generators; Energy storage battery ramping constraints: ; In the formula, This is the maximum active power adjustment rate limit for energy storage batteries.

[0013] Preferably, in S7, the expression for the adaptive scaling of the thickness of the dynamic sliding mode boundary layer with frequency deviation is: ; ; In the formula, The thickness of the boundary layer of the sliding surface. , These are the upper and lower boundaries of the boundary layer thickness of the sliding surface, respectively. It is the scaling factor. It is the frequency deviation after sampling through the event triggering mechanism.

[0014] The present invention also provides a wide-area power grid secondary frequency regulation control system based on bidirectional adaptive event triggering and dynamic boundary layer sliding mode, which applies the above method and includes a state monitoring module, an event triggering decision module, a sliding mode control module, a boundary layer adaptive adjustment module, and a cooperative execution module; Status monitoring module: used to collect the frequency deviation of the wide area power grid in real time, as well as the operating power parameters of the controllable load hydrogen production unit, synchronous generator, and energy storage battery, and transmit them to the event triggering decision module through the communication network; Event-triggered decision module: includes a bidirectional adaptive threshold unit and an event determination unit; the bidirectional adaptive threshold unit is used to dynamically calculate the event trigger threshold based on the real-time frequency deviation; the event determination unit is used to determine the timing of updating and transmitting control commands based on the comparison result between the state deviation and the event trigger threshold. Sliding mode control module: used to generate a sliding mode control law based on an integral sliding surface combined with communication delay compensation when an event is triggered; Boundary layer adaptive adjustment module: used to adaptively adjust the thickness of the sliding mode boundary layer according to the real-time frequency deviation. When the frequency deviation increases, the boundary layer expands to suppress high-frequency chattering, and when the frequency deviation decreases, the boundary layer contracts to improve steady-state control accuracy. Cooperative execution module: Used to receive the final secondary frequency modulation control command after reconstruction by the boundary layer adaptive adjustment module, and accordingly coordinate the active power of the controllable load type energy storage device, the output of the synchronous generator and the charging and discharging power of the energy storage battery.

[0015] A computer device includes a processor, a memory, and a computer program stored in the memory. When the computer program is executed by the processor, it implements the wide-area power grid secondary frequency regulation control method based on bidirectional adaptive event triggering and dynamic boundary layer sliding mode.

[0016] A computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the wide-area power grid secondary frequency regulation control method based on bidirectional adaptive event triggering and dynamic boundary layer sliding mode.

[0017] The present invention employs the above-mentioned wide-area power grid secondary frequency regulation control method and system based on bidirectional adaptive event triggering and dynamic boundary layer sliding mode, and has the following beneficial effects: (1) The present invention adopts a bidirectional adaptive event triggering mechanism, which adjusts the triggering threshold smoothly in both directions according to the system frequency deviation, thereby significantly reducing the wide area communication load and data transmission frequency; effectively avoids the problem of frequent equipment operation caused by the indiscriminate issuance of frequency modulation commands under traditional periodic control, significantly reduces the response frequency and wear of physical frequency modulation equipment, and extends the service life of the equipment; (2) This invention adopts a robust sliding mode control as the core control algorithm and innovatively introduces a dynamic sliding mode boundary layer mechanism controlled by real-time frequency deviation, which completely breaks the inherent contradiction between chattering and control accuracy in traditional sliding mode control. When the wide-area power grid is subjected to strong disturbances and drastic frequency fluctuations, the boundary layer expands adaptively to smooth the control signal, fundamentally suppressing the inherent high-frequency chattering phenomenon of sliding mode control and protecting the hardware from electrical and mechanical losses. When the system tends to a steady state, the boundary layer contracts adaptively, ensuring strict secondary frequency modulation control accuracy. (3) This invention establishes a closed-loop nonlinear model based on the equipment ramp rate constraint, and analyzes the stability based on the Lyapunov-Krasovskii function. With its strong anti-interference capabilities, the sliding mode controller can handle disturbances and delays, ensuring the frequency stability of the wide-area power grid. (4) This invention incorporates a controllable load electric hydrogen production device into frequency regulation, expands the frequency regulation resources of the wide-area power grid through frequency regulation participation factor allocation control commands, and adapts to the source-load fluctuations under high-penetration new energy; Attached Figure Description

[0018] Figure 1 This is a flowchart of a wide-area power grid secondary frequency regulation control method based on bidirectional adaptive event triggering and dynamic boundary layer sliding mode according to an embodiment of the present invention; Figure 2 This is a comparison chart of closed-loop load frequency deviation with P2H device as the variable in an embodiment of the present invention, which is a wide-area power grid secondary frequency regulation control method based on bidirectional adaptive event triggering and dynamic boundary layer sliding mode. Figure 3 This is a comparison chart of closed-loop load frequency deviations using different sliding mode controls in a wide-area power grid secondary frequency regulation control method based on bidirectional adaptive event triggering and dynamic boundary layer sliding mode according to an embodiment of the present invention. Figure 4 This is a comparison diagram of the system control triggering interval with P2H device as the variable in a wide area power grid secondary frequency regulation control method based on bidirectional adaptive event triggering and dynamic boundary layer sliding mode according to an embodiment of the present invention; wherein, (a) is dynamic sliding mode control with P2H added, (b) is dynamic sliding mode control without P2H added, and (c) is negative feedback control with P2H added. Figure 5 This is a comparison diagram of the system control trigger intervals of a wide-area power grid secondary frequency regulation control method based on bidirectional adaptive event triggering and dynamic boundary layer sliding mode according to an embodiment of the present invention; wherein, (a) is dynamic sliding mode control and (b) is static sliding mode control; Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments and the accompanying drawings. It should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0020] Example 1, such as Figure 1As shown, a wide-area power grid secondary frequency regulation control method based on bidirectional adaptive event triggering and dynamic boundary layer sliding mode is presented. This method is executed by computer equipment, specifically by a terminal or server alone, or by a terminal and server working together. In the first embodiment, the method is applied to a controllable load type electro-hydrogen production unit participating in wide-area power grid secondary frequency regulation control as an example for detailed explanation. This includes: 1. Obtain the operating parameters of the wide-area power grid and the operating parameters of the equipment participating in secondary frequency regulation.

[0021] The controllable load type energy storage device is selected as the electric hydrogen production device (P2H); the operating parameters of each device participating in the secondary frequency regulation of the wide area power grid include: the operating parameters of the controllable load type electric hydrogen production device, the operating parameters of the synchronous generator, and the operating parameters of the energy storage battery.

[0022] 2. Based on the operating parameters of the wide-area power grid and the operating parameters of the equipment, construct a dynamic model for open-loop secondary frequency regulation of the wide-area power grid.

[0023] Based on the operating parameters of each device involved in secondary frequency regulation, a frequency-active power response model, a synchronous generator dynamic characteristic model, and an energy storage battery model are constructed for a controllable load-type electro-hydrogen production device. Then, based on the above three types of device models and combined with the operating parameters of the wide-area power grid, an open-loop secondary frequency regulation dynamic model of the wide-area power grid is constructed to accurately describe the multi-source power supply characteristics of the wide-area power grid and the dynamic evolution process of each frequency regulation resource, and to establish a multi-source collaborative wide-area power grid frequency regulation operation architecture.

[0024] In the multi-source collaborative wide-area power grid frequency regulation operation architecture, by deeply integrating controllable load-type electro-hydrogen production devices into the wide-area power grid secondary frequency regulation system, the coordinated optimization and regulation of heterogeneous energy storage resources can be achieved, thereby significantly expanding the active power regulation resource reserves of the wide-area power grid.

[0025] The specific steps include: 2.1 Based on the operating parameters of the equipment involved in secondary frequency regulation, a frequency-active power response model, a synchronous generator dynamic characteristic model, and an energy storage battery model are constructed for a controllable load type electro-hydrogen production device.

[0026] (1) Construct a frequency-electrolysis power response model for P2H equipment.

[0027] Will As the inertial time constant of the electrolytic cell section of the P2H equipment, For the conversion efficiency of the electrolytic cell, This is the reference hydrogen production power adjustment for the P2H equipment.

[0028] and Generally, it is obtained based on the actual operating parameters of P2H equipment. When the electrolysis power of the electrolyzer changes, the conversion efficiency of the electrolyzer will reach a new stable point due to microbubble transport, reactant concentration diffusion and other reasons. This chemical reaction process has typical time delay characteristics, so it is modeled as a first-order inertial link.

[0029] The frequency-electrolysis power response model of P2H equipment is expressed as follows: ; In the formula, This indicates the electrolysis power of the P2H equipment. for The first derivative.

[0030] (2) Construct a dynamic characteristic model of a synchronous generator.

[0031] Synchronous generators (SGs) use governors to control the valve opening, thereby adjusting the natural gas intake to change the mechanical power output of the steam turbine, which in turn drives the synchronous generator to adjust its output electrical power.

[0032] Will As the time constant of the SG speed controller As the time constant of the steam turbine. For the increment of the valve opening of the SG speed controller, for The first derivative. To output mechanical power to the steam turbine, for The first derivative. This is the reference output active power adjustment for SG. For the frequency deviation of the wide area power grid load, Let SG be the droop coefficient. The dynamic characteristic model of the synchronous generator is expressed as: ; ; (3) Construct a battery energy storage (BESS) model.

[0033] BESS responds to the secondary frequency regulation command of the wide-area power grid by adjusting the output active power of the power electronic inverter.

[0034] The energy storage battery model is represented as follows: ; In the formula, The output active power of BESS for The first derivative, For BESS time constant, The BESS unit adjustment factor is used. This is the reference output active power adjustment for BESS.

[0035] 2.2 Based on the frequency-electrolysis power response model of P2H equipment, the dynamic characteristic model of synchronous generator and energy storage battery, and combined with the operating parameters of wide area power grid, a dynamic characteristic model of wide area power grid is constructed.

[0036] When a frequency deviation is caused by uncertain power fluctuations on both the source and load sides of a wide-area power grid, the dynamic characteristic model of the wide-area power grid under the coordinated participation of SG, BESS, and P2H in the secondary frequency regulation of the wide-area power grid is expressed as follows: ; In the formula, and These represent the inertia and damping coefficient of the wide-area power grid, respectively. For photovoltaic power generation output power, The output power of the wind turbine. Due to load fluctuations, For wide area power grid load fluctuations, for The first derivative.

[0037] 2.3 Based on the frequency-electrolysis power response model of P2H equipment, the dynamic characteristic model of synchronous generator, the energy storage battery model, and the dynamic characteristic model of wide-area power grid, an open-loop secondary frequency regulation dynamic model is obtained by adopting the frequency regulation participation condition.

[0038] The expression for the FM participation condition is: ; In the formula, This is the reference output active power adjustment for the synchronous generator. This is the adjustment amount for the reference output active power of the energy storage battery. This is the reference hydrogen production power adjustment amount for the electro-hydrogen production equipment; , and For frequency modulation participation factor, , This is a secondary frequency modulation command.

[0039] Combining the models constructed in steps 2.1 and 2.2 with the frequency regulation participation conditions, an open-loop secondary frequency regulation dynamic model is obtained to represent the open-loop dynamic characteristics of secondary frequency regulation in a wide-area power grid. The secondary frequency regulation dynamic model is represented by state-space equations: ; ; ; ; ; ; ; ; 3. A two-sided dynamic update mechanism is adopted to design the trigger threshold, and the event triggering judgment rules are designed based on the trigger threshold.

[0040] 3.1 Construct an integral sliding surface containing wide-area power grid state variables and integral terms, and derive an equivalent sliding controller for subsequent stability analysis of the system.

[0041] To enhance the robustness of wide-area power grids to secondary frequency regulation under various scenarios, for the controller... A sliding mode control design method is adopted.

[0042] Based on the quadratic frequency modulation model and the state-space equations, the following integral sliding surface is constructed: ; In the formula, It is a definite matrix, and The matrix must satisfy the matrix Reversible.

[0043] Differentiating the above equation, we get: ; When the system state reaches the sliding surface, it satisfies and Equals 0. Substituting the system's state-space equations into the above equation, we get: ; make The equivalent sliding mode controller is obtained: .

[0044] 3.2 Design an event-triggered secondary frequency regulation scheme to reduce the number of responses from the P2H system participating in the secondary frequency regulation of the wide-area power grid. An event-triggered detector is installed to monitor the load operating status information of the wide-area power grid. The reference operating points of each device participating in the secondary frequency regulation of the wide-area power grid are only updated when the operating status of the wide-area power grid degrades to a preset threshold. This effectively reduces the response frequency of frequency regulation equipment, including P2H equipment, and extends their service life.

[0045] The event triggering determination rule is expressed as follows: ; In the formula, The sampling period is , For the current moment Wide area power grid load status quantity and the last trigger time Deviation vector of load state variables in wide-area power grid Let be the performance weight matrix, and ; for The event trigger threshold at any given time. and These represent the first and second consecutive signals that satisfy the triggering condition. The second sampling and the first Second sampling, This indicates the current transmitted wide-area power grid load status quantity.

[0046] Among them, the trigger threshold A bilateral dynamic update mechanism is adopted, which adaptively increases as the control error decreases, to trigger the threshold. Represented as: ; ; In the formula, for The event trigger threshold at any given time. for The frequency deviation of the wide-area power grid load at any given time; , , , ; This is the minimum trigger threshold value; This is the maximum trigger threshold. These are bilateral adaptive parameters.

[0047] When the control error, i.e., the wide-area power grid frequency deviation, decreases, the trigger threshold gradually increases, thereby updating the reference operating points of each device participating in the secondary frequency regulation of the wide-area power grid at a lower interaction frequency, thus reducing the number of times the wide-area power grid load frequency is controlled. Conversely, when the control error increases, the trigger threshold immediately returns to the preset minimum value, thereby controlling each device participating in the secondary frequency regulation of the wide-area power grid at a more frequent interaction frequency, thus increasing the number of times the wide-area power grid frequency is controlled.

[0048] When the frequency deviation increases This means that the trigger threshold gradually decreases from its current value to a preset minimum value. .

[0049] Therefore, in the same scenario, compared with the one-sided dynamic update mechanism, the design of the trigger threshold using the two-sided dynamic update mechanism can further reduce the control frequency, i.e. the interaction frequency, of the secondary frequency regulation of the wide-area power grid.

[0050] 4. Based on the open-loop secondary frequency regulation dynamic model, and combined with the physical power ramp-up rate constraints of the controllable load energy storage device, synchronous generator, and energy storage battery, a closed-loop secondary frequency regulation system model considering nonlinear saturation truncation constraints is constructed. 4.1 Physical power ramp rate constraint.

[0051] Ramp-up constraints include ramp-up constraints for P2H equipment, ramp-up constraints for synchronous generators, and ramp-up constraints for energy storage batteries.

[0052] Assuming the secondary frequency regulation of the wide-area power grid adopts a feedback control scheme, according to the event triggering judgment rule, within the interval between two adjacent event triggers, since the control performance of the secondary frequency regulation of the wide-area power grid has not yet decreased below the preset level, the control command remains unchanged. Therefore, under ideal circumstances, the control command for the secondary frequency regulation of the wide-area power grid within two adjacent trigger intervals is expressed as follows: ; In the formula, To control the gain, For transmission delay, , d To determine the maximum transmission delay, the trigger interval will be... Based on sampling period Divided into sets , , , where, definition ,Depend on have ; Substituting, we get: ; In practical applications, existing commercial P2H equipment is generally constrained by the chemical reaction rate. In order to avoid the risk of explosion caused by a decrease in hydrogen purity due to excessively rapid changes in electrolysis power, it is necessary to strictly limit the electrolysis power ramp-up range of P2H equipment. The same ramp-up rate limit applies to synchronous generators and energy storage batteries. Ramp-up constraints include ramp-up constraints for P2H equipment, ramp-up constraints for synchronous generators, and ramp-up constraints for energy storage batteries.

[0053] ramp-up constraints for power generation hydrogen (P2H) units: ; In the formula, The maximum active power adjustment rate limit for the electro-hydrogen production unit; Synchronous generator ramping constraints: ; In the formula, This is the maximum active power regulation rate limit for synchronous generators; Energy storage battery ramping constraints: ; In the formula, This is the maximum active power adjustment rate limit for energy storage batteries.

[0054] 4.2 Further combining the frequency modulation participation condition in step 2, the actual control command is expressed in nonlinear form. The equivalent control command under this saturation constraint can be expressed as: ; ; In the formula, Represents the saturation function. A function describing the degree of nonlinear saturation. The physical meaning of is to characterize the difference between the ideal control input and the actual input. The points where the graph of the function intersects the horizontal axis are respectively and .

[0055] Further define the function ; and The graphs of the functions intersect at two points with x-coordinates, namely... and And satisfy: ; ; Therefore, for any positive definite matrix Π, we always have: ; Finally, based on the open-loop secondary frequency modulation dynamic model and the above description, the closed-loop secondary frequency modulation system model is obtained, which is expressed as: ; .

[0056] 5. Stability analysis of wide-area power grid systems based on Lyapunov-Krasovskii functional theory and To improve anti-interference performance, a first set of matrix inequalities containing controller gain and event triggering parameters is constructed. The linear matrix inequalities are then linearized using congruent transformation to obtain a set of linear matrix inequalities. Solving the set of linear matrix inequalities yields the controller feedback gain and event triggering weight matrix parameters, resulting in a closed-loop secondary frequency modulation scheme.

[0057] 5.1 Based on the event triggering judgment rule and the closed-loop quadratic frequency modulation model, the first set of linear matrix inequalities is obtained using Lyapunov stability theory.

[0058] Given scalar , , , , If a matrix exists and symmetric positive definite matrices P , Q , M , R If Φ and Π satisfy the first set of matrix inequalities, then the wide-area power grid LFC system with event-triggered mechanism is asymptotically stable under the bounded transmission delay [0, d], and is responsive to external power. Damping performance. The first set of matrix inequalities is expressed as: ; ; In the formula, , , , , , , , , , , , , , , , , , , , , , , .

[0059] 5.2. Eliminate nonlinear terms by using cong{Λ,Λ} and diag{Λ,Λ,Λ,Λ,I,Ψ,Λ,I} respectively on the left and right sides of the first matrix inequality group, where Λ = P -1 ,Ψ=Π -1 , , , , , This yields the second set of linear matrix inequalities.

[0060] Given scalar , , , , If scalars and matrices exist , Y and positive definite matrix Θ , , , The second linear matrix inequality is satisfied, therefore the closed-loop LFC system is asymptotically stable, and the sliding mode controller gain is... K = Y -1 The performance weight matrix is The second set of linear matrix inequalities is: ; ; In the formula, , , , , , , , , , , , , , , , , , , , , , , , .

[0061] 5.3. Based on the second set of linear matrix inequalities, the event triggering judgment rule and the control parameters of the closed-loop quadratic frequency modulation model are obtained, namely, the performance weight matrix in the event triggering judgment rule and the sliding mode controller control gain and performance weight matrix in the closed-loop quadratic frequency modulation model. Sliding mode controller gain K = Y -1 ; Based on the control parameters, event triggering rules, and closed-loop secondary frequency modulation model, a closed-loop secondary frequency modulation scheme is obtained.

[0062] 6. Design a suitable sliding mode control law so that the system state can reach the sliding surface and slide along the sliding surface within a finite time, thereby enhancing the robustness of the wide-area power grid in the face of uncertain load disturbances.

[0063] For wide-area power grid systems, under the action of event-triggered mechanisms, there exists a scalar , making ||e ( i k h )||≤ γ || x ( t k h According to the event triggering rules, there is a period of time between two event triggers. ,Right now: ; In the formula, λ min and λ max These are the minimum and maximum eigenvalues ​​of the positive definite matrix Φ, respectively. ,make Then you can get .

[0064] The difference between the actual input and the ideal input There exists an upper bound value. , making the inequality Established. According to The definition has Combined with the following formula: ; You can get ∥ ( u ( t ))∥ / λ ≤ u max +∥ ( u ( t After sorting the items, we get: ,in .make Then the above equation is proved.

[0065] Design a time-triggered load frequency sliding mode control law. u ( t To ensure that the sliding surface meets the requirements If < 0 is true, then the following formula should be satisfied: ; ; In the formula, ε=γ ( JB ) -1 || JBK |||| x ( t k h )||+ ρ || JB ||+ W || JH ||+ ε 0, ε 0 > 0 is a given small scalar, and ϒ is the boundary layer thickness of the sliding surface.

[0066] 7. Real-time acquisition of the wide-area power grid load frequency deviation, and adoption of a closed-loop secondary frequency regulation scheme. When the wide-area power grid load frequency deviation decreases, the control frequency of the closed-loop secondary frequency regulation scheme on the wide-area power grid load frequency is reduced; when the wide-area power grid load frequency deviation increases, the control frequency of the closed-loop secondary frequency regulation scheme on the wide-area power grid load frequency is increased to stabilize the wide-area power grid load frequency.

[0067] During the execution of the closed-loop secondary frequency regulation scheme, a dynamic sliding mode boundary layer controlled by the real-time frequency deviation is introduced. Based on the real-time evolution characteristics of the wide-area power grid load frequency deviation, the boundary layer thickness of the sliding mode controller is adaptively adjusted. Specifically, through the adaptive scaling adjustment of the dynamic sliding mode boundary layer, the inherent high-frequency chattering of sliding mode control is suppressed, and the steady-state control accuracy of the secondary frequency regulation is ensured. Its dynamic evolution process includes: During the execution cycle of the secondary frequency control controller, the real-time collected wide-area power grid frequency deviation is used as the state input, driving the boundary layer thickness to scale in real time according to the magnitude of the frequency deviation: ; ; In the formula, The thickness of the boundary layer of the sliding surface. , These are the upper and lower boundaries of the boundary layer thickness of the sliding surface, respectively. It is the scaling factor. It is the frequency deviation after sampling through the event triggering mechanism.

[0068] When the frequency deviation of the wide-area power grid load increases, it indicates that the system is subjected to strong external active power disturbance. At this time, the dynamic sliding mode boundary layer is driven to expand adaptively. The discontinuous switching terms in the sliding mode control law are smoothed by the continuous saturation function, thereby smoothing the output signal of the control law. This fundamentally suppresses the high-frequency chattering phenomenon inherent in sliding mode control and protects the actuators of the controllable load type electric hydrogen production device, gas turbine generator and energy storage battery from mechanical and electrical wear. When the load frequency deviation of the wide-area power grid decreases, it indicates that the unbalanced power of the system is gradually suppressed. At this time, the dynamic sliding mode boundary layer is driven to adaptively shrink, reducing the steady-state error convergence domain of the control system, thereby strictly ensuring the steady-state control accuracy of the closed-loop secondary frequency regulation scheme and realizing the coordinated control of load frequency with high precision and chatter suppression in the wide-area power grid.

[0069] This invention discloses a wide-area power grid secondary frequency regulation control system based on bidirectional adaptive event triggering and dynamic boundary layer sliding mode, comprising a state monitoring module, an event triggering decision module, a sliding mode control module, a boundary layer adaptive adjustment module, and a cooperative execution module. Status monitoring module: used to collect the frequency deviation of the wide area power grid in real time, as well as the operating power parameters of the controllable load hydrogen production unit, synchronous generator, and energy storage battery, and transmit them to the event triggering decision module through the communication network; Event-triggered decision module: includes a bidirectional adaptive threshold unit and an event determination unit; the bidirectional adaptive threshold unit is used to dynamically calculate the event trigger threshold based on the real-time frequency deviation; the event determination unit is used to determine the timing of updating and transmitting control commands based on the comparison result between the state deviation and the event trigger threshold. Sliding mode control module: used to generate a sliding mode control law based on an integral sliding surface combined with communication delay compensation when an event is triggered; Boundary layer adaptive adjustment module: used to adaptively adjust the thickness of the sliding mode boundary layer according to the real-time frequency deviation. When the frequency deviation increases, the boundary layer expands to suppress high-frequency chattering, and when the frequency deviation decreases, the boundary layer contracts to improve steady-state control accuracy. Cooperative execution module: Used to receive the final secondary frequency modulation control command after reconstruction by the boundary layer adaptive adjustment module, and accordingly coordinate the active power of the controllable load type energy storage device, the output of the synchronous generator and the charging and discharging power of the energy storage battery.

[0070] Example 2: Simulation Verification.

[0071] To verify the effectiveness of the electrogenerated hydrogen-assisted secondary frequency regulation method for isolated wide-area power grids, a simulation model was built in the Matlab / Simulink environment. The P2H device was selected as an alkaline electrolyzer, and the relevant simulation parameters are shown in Table 1. The sampling time of the simulation model was 0.01 s, and the external power disturbance w(t) experienced by the system was... t The signal occurs at t=1s and is set as a step signal with a peak value of 0.1. The effectiveness of the electro-hydrogen-assisted islanded wide-area power grid secondary frequency regulation method in this embodiment is verified by comparing the closed-loop secondary frequency regulation scheme assisted by the P2H device with that assisted by the P2H device. Simulation parameter settings are shown in Table 1.

[0072] Table 1 Simulation Parameter Settings

[0073] Simulation results for the closed-loop secondary frequency modulation scheme assisted by the P2H device and the closed-loop secondary frequency modulation scheme without the P2H device are shown in Table 2. Figure 2 , Figure 3 , Figure 4 , Figure 5 As shown.

[0074] Table 2 Simulation Results

[0075] The results show that the frequency deviation absolute value integral (IAE) of the scheme provided by the present invention is reduced by 31.1% and 31.7% respectively compared with the scheme using negative feedback control and without P2H device, the frequency deviation peak value is reduced by 25.2% and 31.2%, and the cumulative trigger number is only 2 more than the method using negative feedback control, and 32 fewer than the scheme without P2H device.

[0076] It is evident that when performing secondary frequency regulation on a wide-area power grid, combining a P2H device with a sliding mode controller can effectively enhance the anti-interference capability of the entire system and accelerate the system's regulation speed.

[0077] Therefore, this invention adopts the above-mentioned wide-area power grid secondary frequency regulation control method and system based on bidirectional adaptive event triggering and dynamic boundary layer sliding mode. 1) It adopts a bidirectional adaptive event triggering mechanism, which adjusts the trigger threshold according to the smooth evolution of the system frequency deviation in both directions, significantly reducing the wide-area communication load and data transmission frequency; effectively avoiding the problem of frequent equipment operation caused by the indiscriminate issuance of frequency regulation commands under traditional periodic control, significantly reducing the response frequency and wear of physical frequency regulation equipment, and extending the service life of the equipment; 2) It adopts a sliding mode control with strong robustness as the core control algorithm, and innovatively... A dynamic sliding mode boundary layer mechanism controlled by real-time frequency deviation is introduced, completely breaking the inherent contradiction between chattering and control accuracy in traditional sliding mode control. When the wide-area power grid is subjected to strong disturbances and drastic frequency fluctuations, the boundary layer adaptively expands to smooth the control signal, fundamentally suppressing the inherent high-frequency chattering phenomenon of sliding mode control and protecting the hardware from electrical and mechanical losses. When the system tends to a steady state, the boundary layer adaptively contracts, ensuring strict secondary frequency modulation control accuracy. 3) A closed-loop nonlinear model is established in conjunction with equipment ramp-up rate constraints, and stability is analyzed based on the Lyapunov-Krasovskii function. Anti-interference performance: The sliding mode controller can cope with disturbances and delays, ensuring the frequency stability of the wide-area power grid; 4) Incorporate controllable load electric hydrogen production devices into frequency regulation, expand the frequency regulation resources of the wide-area power grid through frequency regulation participation factor allocation control commands, and adapt to the source-load fluctuations under high-penetration new energy.

[0078] It is worth noting that all contents not described in detail in this invention are existing technologies and are well known to those skilled in the art.

[0079] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A wide-area power grid secondary frequency regulation control method based on bidirectional adaptive event triggering and dynamic boundary layer sliding mode, characterized in that, Includes the following steps: S1. Obtain the operating parameters of the wide area power grid and the operating parameters of the equipment participating in secondary frequency regulation, wherein the equipment includes a controllable load type energy storage device, a synchronous generator and an energy storage battery; S2. Based on the operating parameters of the wide area power grid and the operating parameters of the equipment, construct a dynamic model for open-loop secondary frequency regulation of the wide area power grid; S3. Construct an integral sliding surface containing wide-area power grid state variables and integral terms, and derive the equivalent sliding controller. S4. Design a bidirectional adaptive event triggering mechanism to generate event triggering thresholds that are smoothly and gradually adjusted in both directions as the state deviation of the wide-area power grid system increases or decreases. Based on the event triggering threshold, an event triggering determination rule is constructed to determine whether the status data of the wide area power grid system needs to be transmitted; S5. Combining the open-loop secondary frequency regulation dynamic model with the physical power ramp-up rate constraints of the controllable load energy storage device, synchronous generator, and energy storage battery, construct a closed-loop secondary frequency regulation system model considering nonlinear saturation truncation constraints. S6. Stability analysis of wide-area power grid systems based on Lyapunov-Krasovskii functional analysis and To improve anti-interference performance, a first set of matrix inequalities containing controller gain and event triggering parameters is constructed. The linear matrix inequalities are linearized using the congruent transformation technique to obtain a linear set of matrix inequalities. Solving the linear set of matrix inequalities yields the controller feedback gain and event triggering weight matrix parameters. S7. Design an event-triggered secondary frequency modulation sliding mode control law and introduce a dynamic sliding mode boundary layer that adaptively scales with the real-time frequency deviation. S8. Real-time acquisition of wide-area power grid frequency deviation, and issuance of secondary frequency regulation power control command by driving sliding mode control law according to the event triggering judgment rule; when the frequency deviation increases, the dynamic sliding mode boundary layer adaptively expands to suppress high-frequency chattering of the system; when the frequency deviation decreases, the dynamic sliding mode boundary layer adaptively contracts to improve the steady-state control accuracy of secondary frequency regulation.

2. The wide-area power grid secondary frequency regulation control method based on bidirectional adaptive event triggering and dynamic boundary layer sliding mode as described in claim 1, characterized in that, In S2, the steps for constructing the open-loop secondary frequency regulation dynamic model of the wide-area power grid include: S21. Select the electric hydrogen production device as a controllable load type energy storage device, and construct it as a first-order inertial frequency-power response model to obtain the frequency-active power response model of the electric hydrogen production device. S22. Construct a dynamic characteristic model of a synchronous generator, including a governor dynamic characteristic model and a turbine dynamic characteristic model; S23. Construct a linear regulation model for energy storage batteries; S24. Combine the frequency-active power response model of the electric hydrogen production device, the dynamic characteristic model of the synchronous generator, the linear regulation model of the energy storage battery, and the frequency deviation feedback relationship in the operating parameters of the wide area power grid. Use the frequency regulation participation condition to construct the control command allocation relationship of the wide area power grid and establish an open-loop secondary frequency regulation dynamic model of the wide area power grid.

3. The wide-area power grid secondary frequency regulation control method based on bidirectional adaptive event triggering and dynamic boundary layer sliding mode according to claim 2, characterized in that, In S24, the expression for the frequency modulation participation condition is: ； In the formula, This is the reference output active power adjustment for the synchronous generator. This is the adjustment amount for the reference output active power of the energy storage battery. This is the reference hydrogen production power adjustment amount for the electro-hydrogen production equipment; , and For frequency modulation participation factor, , This is a secondary frequency modulation command.

4. The wide-area power grid secondary frequency regulation control method based on bidirectional adaptive event triggering and dynamic boundary layer sliding mode as described in claim 1, characterized in that, In S4, the event triggering threshold is adjusted through the following bilateral dynamic update mechanism: ； ； In the formula, for The event trigger threshold at any given time. for The frequency deviation of the wide-area power grid load at any given time; , , , ; This is the minimum trigger threshold value; This is the maximum trigger threshold. These are bilateral adaptive parameters.

5. The wide-area power grid secondary frequency regulation control method based on bidirectional adaptive event triggering and dynamic boundary layer sliding mode according to claim 1, characterized in that, In S5, the physical power ramp rate constraint includes: Ramp-up constraints for electro-hydrogen production units: ； In the formula, The maximum active power adjustment rate limit for the electro-hydrogen production unit; Synchronous generator ramping constraints: ； In the formula, This is the maximum active power regulation rate limit for synchronous generators; Energy storage battery ramping constraints: ； In the formula, This is the maximum active power adjustment rate limit for energy storage batteries.

6. The wide-area power grid secondary frequency regulation control method based on bidirectional adaptive event triggering and dynamic boundary layer sliding mode according to claim 1, characterized in that, In S7, the expression for the adaptive scaling of the thickness of the dynamic sliding mode boundary layer with frequency deviation is: ； ； In the formula, The thickness of the boundary layer of the sliding surface. , These are the upper and lower boundaries of the boundary layer thickness of the sliding surface, respectively. It is the scaling factor. It is the frequency deviation after sampling through the event triggering mechanism.

7. A wide-area power grid secondary frequency regulation control system based on bidirectional adaptive event triggering and dynamic boundary layer sliding mode, using the method of any one of claims 1-6, characterized in that, It includes a state monitoring module, an event-triggered decision-making module, a sliding mode control module, a boundary layer adaptive adjustment module, and a cooperative execution module; Status monitoring module: used to collect the frequency deviation of the wide area power grid in real time, as well as the operating power parameters of the controllable load hydrogen production unit, synchronous generator, and energy storage battery, and transmit them to the event triggering decision module through the communication network; Event-triggered decision module: includes a bidirectional adaptive threshold unit and an event determination unit; The bidirectional adaptive threshold unit is used to dynamically calculate the event trigger threshold based on the real-time frequency deviation; the event determination unit is used to decide the timing of updating and transmitting control commands based on the comparison result between the state deviation and the event trigger threshold. Sliding mode control module: used to generate a sliding mode control law based on an integral sliding surface combined with communication delay compensation when an event is triggered; Boundary layer adaptive adjustment module: used to adaptively adjust the thickness of the sliding mode boundary layer according to the real-time frequency deviation. When the frequency deviation increases, the boundary layer expands to suppress high-frequency chattering, and when the frequency deviation decreases, the boundary layer contracts to improve steady-state control accuracy. Cooperative execution module: Used to receive the final secondary frequency modulation control command after reconstruction by the boundary layer adaptive adjustment module, and accordingly coordinate the active power of the controllable load type energy storage device, the output of the synchronous generator and the charging and discharging power of the energy storage battery.

8. A computer device, comprising a processor, a memory, and a computer program stored in the memory, characterized in that, When the computer program is executed by the processor, it implements the wide-area power grid secondary frequency regulation control method based on bidirectional adaptive event triggering and dynamic boundary layer sliding mode as described in any one of claims 1-6.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the wide-area power grid secondary frequency regulation control method based on bidirectional adaptive event triggering and dynamic boundary layer sliding mode as described in any one of claims 1-6.

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