Improvement method and system for overcoming frequency modulation mechanical dead zone of water turbine governor

Abstract

The invention belongs to the technical field of power system control, and the method comprises the following steps: improving a manual failure area unit of primary frequency modulation, when a frequency deviation delta F'exceeds a frequency dead zone Ef, increasing a superposition amount for the calculated frequency deviation delta F, and when primary frequency modulation action is carried out, adding a delay filtering link; optimization is carried out on the superposition amount and the delay link for adaptive adjustment, and prediction and multi-stage frequency modulation are carried out during a primary frequency modulation action; and when the primary frequency is reset, a return difference link is added. According to the method, the algorithm of the manual failure area is improved, a step-type frequency superposition amount is added to the calculated frequency difference, and the adjustment amount of frequency modulation is increased, so that the problem of insufficient integration of frequency modulation is overcome; when the frequency deviation is weak, a step type is added to form a larger output signal, the signal output form is a sudden change form, and the dead zone of each link is overcome; time delay and return difference are increased, and frequent jitter which is useless for primary frequency modulation and is caused by frequency crossing of a frequency dead zone edge of a power grid system is prevented.

Description

Technical Field

[0001] This invention belongs to the field of power system control technology, and in particular, it is an improved method for overcoming the mechanical dead zone of frequency regulation in a hydro turbine governor. Background Technology

[0002] Primary frequency regulation is one of the essential functions of a hydropower unit, and it is implemented in the turbine governor. Currently, the conventional method for implementing primary frequency regulation is relatively simple: when the governor detects that the frequency fluctuation of the power grid system exceeds the artificially set dead zone (the frequency regulation dead zone), it outputs a change in the guide vane (or active power) corresponding to the frequency range, according to the droop formula. This changes the guide vane opening and the unit's active power, ultimately achieving a balance between power generation and load consumption, thereby ensuring that the system frequency remains within the rated frequency range.

[0003] However, due to the existence of electrical dead zones (inherent calculation cycle, digital-to-analog conversion delay, etc.) and mechanical dead zones (caused by mechanical stress deformation, idle travel between hinges, etc.) and friction in the various components of the speed governor, transmission mechanism, and water guiding mechanism, the final change in guide vane opening is often less than the theoretically calculated change during actual operation. Under a certain frequency difference, insufficient guide vane opening will lead to insufficient active power change. The power grid, based on its primary frequency regulation assessment calculation method, verifies the actual active power change against the theoretical calculation. Through statistical analysis of assessment big data, if the number of instances of insufficient change is less than 80%, the power plant is assessed based on insufficient primary frequency regulation integral power, resulting in significant economic losses for the power plant. Simultaneously, the problem of insufficient primary frequency regulation integral power also weakens the contribution of primary frequency regulation to the frequency adjustment of the power grid system, thus reducing the effectiveness of frequency regulation.

[0004] Therefore, this invention proposes a new frequency regulation method based on existing primary frequency regulation. This method can greatly improve the response speed of primary frequency regulation, compensate for the problem of insufficient integrated power, avoid power plant being subject to grid assessment, and also improve the performance of precise frequency regulation of the power grid system. Summary of the Invention

[0005] In view of the aforementioned existing problems, this invention is proposed. This invention proposes an improved method and system for overcoming the mechanical dead zone of a turbine governor. This invention provides an improved method for primary frequency regulation of a hydroelectric unit, solving the problem of insufficient action caused by the mechanical dead zone in turbine governors during minute adjustments. The key to this invention is to add a small amount of compensation during frequency regulation, increase the action delay, and reduce the hysteresis during return. This ensures that the primary frequency regulation action is sufficiently large, preventing malfunctions and avoiding frequent adjustments.

[0006] To address the aforementioned technical problems, an improved method for overcoming the mechanical dead zone of frequency regulation in a turbine governor is proposed, including:

[0007] An improvement is made to the artificial failure zone unit of primary frequency modulation, when the frequency deviation ΔF' exceeds the frequency dead zone E. f Then, a superposition amount is added to the calculated frequency deviation ΔF. When performing a frequency modulation operation, a delay filtering stage is added. The superposition amount and delay stage are optimized and adaptively adjusted. Prediction and multi-level frequency modulation are performed during a frequency modulation operation. A hysteresis stage is added during a frequency recovery process.

[0008] As a preferred embodiment of the improved method for overcoming the mechanical dead zone of frequency regulation in the turbine governor described in this invention, the increased superposition amount includes when the frequency setpoint and the system frequency deviation ΔF' exceed the artificial failure zone E. f Then, the frequency difference in the two directions of the calculated frequency deviation ΔF—the open and closed directions of the guide vane—is calculated. When the frequency is higher than the upper dead zone, the guide vane is closed; when the frequency is lower than the lower dead zone, the guide vane is open. An additional, unconditional θ is added, thereby increasing the magnitude of |ΔF|.

[0009] When ΔF < ΔF', it is considered that the dead zone has been entered, and frequency modulation is performed; if ΔF' > E... f Then ΔF = ΔF' - E f +θ, at this point the system is at high frequency, and a frequency modulation action is performed.

[0010] If ΔF' < -E f Then ΔF=ΔF'-(-E) f )+(-θ)=ΔF+E f -θ, at this point the system is at a low frequency, and a frequency adjustment action is performed.

[0011] Where θ is confined to (0, E) f It can adapt to different compensation requirements for different actual actuation amounts of guide vane opening within a certain range.

[0012] As a preferred embodiment of the improved method for overcoming the mechanical dead zone of frequency regulation in the turbine governor described in this invention, the addition of a hysteresis loop includes adding a hysteresis loop in the primary frequency regulation return stage: when -(E f -0.01)≤ΔF'≤E f When the value is -0.01, ΔF = 0, and a frequency modulation reset is performed, increasing the hysteresis by 0.01Hz. If the reset condition is not met, the process waits to execute the frequency modulation action.

[0013] As a preferred embodiment of the improved method for overcoming the mechanical dead zone of frequency regulation in the turbine governor described in this invention, the added delay filtering stage includes adding a delay filtering stage T after ΔF, which monitors the grid frequency deviation ΔF in real time. When ΔF is less than X, the timing delay begins. When the delay satisfies T∈[x,y], the frequency difference is adjusted and PID calculation is performed to obtain the guide vane setpoint change.

[0014] As a preferred embodiment of the improved method for overcoming the mechanical dead zone of frequency regulation in the turbine governor described in this invention, the adaptive adjustment of the superposition amount and delay element includes real-time monitoring of the system's frequency deviation, analysis and modeling of the system's historical data, and adjustment of the superposition amount and delay element through an adaptive control algorithm, with an adaptive rate of:

[0015] u(t) = u(t-1) + Δu(t)

[0016] Δu(t)=e(t)*ε

[0017] e(t) = r(t) - y(t)

[0018] Where Δu(t) is the adjustment amount calculated based on the error function and the adaptive law, r(t) is the output of the reference model, y(t) is the output of the actual system, e(t) is the error function, and ε is the adaptive law coefficient.

[0019] As a preferred embodiment of the improved method for overcoming the mechanical dead zone of frequency regulation in the turbine governor described in this invention, the multi-level frequency regulation includes performing a multi-level frequency regulation strategy in a single frequency regulation operation. Based on the magnitude of the frequency deviation ΔF, the current frequency regulation levels are determined to be: first-level frequency regulation, second-level frequency regulation, and third-level frequency regulation. Based on the current frequency regulation level n, the corresponding frequency regulation action is selected, and the corresponding frequency regulation action is executed.

[0020] ΔP f =K n *Δf

[0021] Where, ΔP f Δf is the frequency modulation quantity, K is the frequency modulation coefficient, n is the frequency modulation level (n = 1, 2, 3), and Δf is the frequency difference signal.

[0022] As a preferred embodiment of the improved method for overcoming the mechanical dead zone of frequency regulation in the turbine governor described in this invention, the predictive control frequency regulation includes, during a single frequency regulation operation, predicting the trend of system frequency change in advance through a predictive control algorithm: establishing a prediction model based on the current system state and historical data.

[0023]

[0024] in, ω is the autoregressive coefficient. n ΔF'(t) and ΔF'(h) are the current system frequency modulation deviation and the historical system frequency modulation deviation given by the system, respectively, and ΔF(t) and ΔF(h) are the calculated current system frequency modulation deviation and the historical system frequency modulation deviation.

[0025] Based on the prediction model, the trend of system frequency change is predicted, and the guide vane is adjusted accordingly: if Δf(t) exceeds the prediction threshold, it indicates that the system frequency will rise, so the guide vane opening is increased to increase the system's power generation; if Δf(t) is less than the prediction threshold, it indicates that the system frequency will fall, so the guide vane opening is decreased to reduce the system's power generation.

[0026] Another objective of this invention is to provide an improved system for overcoming the mechanical dead zone of frequency regulation in a turbine governor. This invention improves the performance of the turbine governor in terms of frequency regulation mechanical dead zone, thereby enhancing the governor's stability and efficiency. Through the combined action of components such as a superimposed quantity adjustment module, a prediction and optimization module, a hysteresis module, and a delay module, optimized control of the turbine governor is achieved. In this process, the system can monitor and predict the operating state of the turbine governor in real time, adjusting its parameters to eliminate the frequency regulation mechanical dead zone, thus achieving more precise and faster turbine speed regulation. Simultaneously, the system can adapt to load changes in the turbine governor, ensuring its stable operation under various operating conditions. This system aims to improve the performance of the turbine governor, reduce energy consumption, and improve the operating efficiency of the power system.

[0027] As a preferred embodiment of the improved system for overcoming the mechanical dead zone of frequency regulation in the turbine governor described in this invention, it includes: a superposition adjustment module, a prediction and optimization module, a hysteresis module, and a delay module.

[0028] The superposition adjustment module improves the artificial failure zone unit of primary frequency regulation by adding a frequency superposition, thereby increasing the electrical output at the moment the primary frequency regulation action begins. This overcomes the dead zone and inertia of the mechanical and hydraulic links, increases the guide vane opening to deepen the change in the guide vane, avoids the power plant's primary frequency regulation being assessed by the power grid, increases the contribution of primary frequency regulation, and facilitates precise frequency control of the power grid.

[0029] The prediction and optimization module provides adjustment strategies for the turbine governor by predicting the grid load over a future period, maintaining a stable operating state when the grid load changes, and optimizing the superposition amount and delay of the turbine governor according to the changes in grid load.

[0030] The hysteresis module adds a hysteresis stage to the frequency recovery process, meaning the hysteresis dead zone is less than the frequency dead zone and less than 0.01Hz.

[0031] The delay module adds a delay filter during a frequency modulation operation to prevent frequent adjustments caused by frequency jitter and mismeasurement, thus ensuring a smooth transition of the speed controller's output signal.

[0032] A computer device includes a memory and a processor, the memory storing a computer program, characterized in that the processor executes the computer program as a step in a method for improving a turbine governor to overcome a frequency regulation mechanical dead zone.

[0033] A computer-readable storage medium having a computer program stored thereon, characterized in that the computer program, when executed by a processor, is the step of a method for improving a turbine governor to overcome a frequency regulation mechanical dead zone.

[0034] The beneficial effects of this invention are as follows: This solution improves upon the principle of ordinary primary frequency regulation, mainly by improving the algorithm for the artificial failure zone, specifically by adding a step-type frequency superposition to the calculated frequency difference. This has two advantages: first, it increases the adjustment range of frequency regulation, thereby overcoming the problem of insufficient integration in frequency regulation; second, when the frequency deviation is slight, adding this step-type superposition can generate a larger output signal, with the signal output in an abrupt form, which is beneficial for overcoming dead zones in various stages; and third, by adding delay and hysteresis in the primary frequency regulation action and return stage, it can prevent frequent jitter caused by the power grid system frequency crossing the frequency dead zone edge, which is detrimental to primary frequency regulation. Attached Figure Description

[0035] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, wherein:

[0036] Figure 1 The above is a flowchart of an improved method for overcoming the mechanical dead zone of frequency regulation in a water turbine governor, as provided in one embodiment of the present invention.

[0037] Figure 2 The diagram shows the characteristic curves of the unit in the artificial failure zone (frequency dead zone) before improvement of an improved method for overcoming the mechanical dead zone of frequency regulation in a turbine governor, as provided in an embodiment of the present invention.

[0038] Figure 3 This is a simplified diagram illustrating the calculation of frequency regulation deviation before the improvement of an improved method for overcoming the mechanical dead zone of frequency regulation in a turbine governor, as provided in an embodiment of the present invention.

[0039] Figure 4This is a schematic diagram of the dead zone distribution in the guide vane control stage of an improved method for overcoming the mechanical dead zone of a frequency-regulating turbine governor, provided as an embodiment of the present invention.

[0040] Figure 5 This is a schematic diagram of the guide vane variation curve of a turbine unit under actual grid frequency fluctuations, provided as an embodiment of the present invention, for an improved method of overcoming the mechanical dead zone of frequency regulation in a turbine governor.

[0041] Figure 6 The above is a unit characteristic curve of the artificial failure zone (frequency dead zone) of the primary frequency regulation after the improvement of the improved method of the turbine governor to overcome the mechanical dead zone of frequency regulation provided in an embodiment of the present invention.

[0042] Figure 7 This is a simplified diagram illustrating the improved primary frequency regulation differential calculation method for a turbine governor that overcomes the mechanical dead zone of frequency regulation, as provided in an embodiment of the present invention.

[0043] Figure 8 The present invention provides a system functional architecture diagram of an improved system for overcoming the mechanical dead zone of frequency regulation in a turbine governor according to an embodiment of the present invention. Detailed Implementation

[0044] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0045] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0046] Secondly, the term "an embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places throughout this specification does not necessarily refer to the same embodiment, nor is it an embodiment that is mutually exclusive, either alone or selectively, with other embodiments.

[0047] This invention is described in detail with reference to the schematic diagrams. When detailing the embodiments of this invention, for ease of explanation, the cross-sectional views illustrating the device structure may be partially enlarged, not adhering to the usual scale. Furthermore, the schematic diagrams are merely examples and should not be construed as limiting the scope of protection of this invention. In actual fabrication, the three-dimensional spatial dimensions of length, width, and depth should be included.

[0048] Furthermore, in the description of this invention, it should be noted that the terms "upper," "lower," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are used solely for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. In addition, the terms "first," "second," or "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0049] Unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" in this invention should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; similarly, they can refer to mechanical connections, electrical connections, or direct connections, or indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0050] Example 1

[0051] Reference Figures 1-7 This is the first embodiment of the present invention, which provides an improved method for overcoming the mechanical dead zone of frequency regulation in a turbine governor, comprising:

[0052] For hydropower units, such as Figure 4 As shown, in the control stage of the governor guide vane opening, dead zones caused by various factors, such as the inherent pitch of the main and auxiliary components, mechanical deformation, friction, and equipment mass inertia, all contribute to the dead zone. These dead zones cause the guide vane opening feedback to not be completely consistent with the guide vane setpoint. That is, after a frequency regulation operation is calculated, the governor guide vane setpoint will change by a certain amount, but the final change in guide vane opening may not be consistent with the theoretical calculation, i.e., ΔY. F ≠ΔY c There is a discrepancy between the two, and ΔY F Less than ΔY c Since the actual change in guide vane volume is insufficient, the resulting change in active power is also insufficient. Therefore, it is easy to understand why power plant units experience insufficient integrated power output for performance assessment.

[0053] Similarly, when the generating unit operates under a large power grid, its frequency fluctuations are slow, the gradient is gentle, and the amplitude is weak. This results in a gentle change in the guide vane setpoint ΔYc, making the signal output less conducive to generating a strong execution signal to overcome various dead zones in the execution process. This process can be... Figure 5The red curve above represents the frequency fluctuation of the power grid system, and outside the frequency dead zone, its change process, calculated according to the guide vane setting, is represented by the blue curve, which mirrors the frequency. However, the speed governor is a mechanical, electrical, and hydraulic system. The guide vane setting is a digital quantity change, and the guide vane feedback will not perfectly follow it in time, and the action amount is also insufficient, as can be seen from the black curve in the figure.

[0054] In view of the two inherent problems mentioned above that are difficult to solve on their own, this invention proposes a new primary frequency regulation method to address the issue of insufficient guide vane (active power) actuation in actual primary frequency regulation operation. This method can be defined as "improved" primary frequency regulation. The main idea is to add a nonlinear processing step, i.e., adding a frequency superposition, in the manual failure zone. This allows for a larger electrical output at the instant the primary frequency regulation begins. This not only effectively overcomes the dead zone and inertia of the mechanical-hydraulic links but also adds an extra guide vane opening, significantly increasing the guide vane variation. This prevents the power plant's primary frequency regulation from being assessed by the power grid and also increases the contribution of primary frequency regulation, facilitating precise frequency control of the power grid.

[0055] S1: Improve the artificial failure zone unit for primary frequency modulation; when the frequency deviation ΔF' exceeds the frequency dead zone E... f Then, a superposition amount is added to the calculated frequency deviation ΔF, and a delay filtering stage is added when a frequency modulation action is performed.

[0056] The primary frequency regulation function is only invoked when the unit is operating in grid-connected mode. Since the unit's frequency is the same as the grid system frequency, the frequency deviation is the frequency setpoint F. c With unit frequency F g The difference in feedback, i.e., ΔF' = F c -F g .

[0057] Before the improvement, the artificial failure zone (frequency dead zone) unit was a unit that, under automatic operation, could be manually controlled within a specified range of controlled parameters to prevent the speed controller from adjusting. Its characteristic curve was as follows: Figure 2 As shown, its mathematical expression is:

[0058] If ΔF'>E f Then ΔF = ΔF' - E f The system operates at high frequency, with a single frequency modulation action.

[0059] If ΔF' < -E f Then ΔF=ΔF'-(-E) f )=ΔF+E f The system operates at low frequency, requiring a single frequency modulation action.

[0060] If -E f≤ΔF'≤E f If ΔF = 0, then the frequency modulation returns to normal.

[0061] E f The typical value range is 0–0.5 Hz, but it is usually set to 0.05 Hz when the primary frequency regulation function is activated. The common practice in China for calculating the primary frequency regulation droop formula is as follows: when the power grid system frequency changes, the change ΔF′′ exceeds (-E... f E f After passing through an artificial failure zone unit, the ΔF value is obtained, and then this value is adjusted and calculated, such as... Figure 3 As shown. The given change in guide vane ΔY is obtained. c , that is ΔY c = ΔF / bp. Where bp is the permanent slip coefficient, which is a set value, generally in the range of 0 to 10%, and the domestic empirical value is generally 4%.

[0062] Preferably, the improved setting is when the frequency deviation ΔF' from the system frequency exceeds the artificial failure zone E. f Then, the frequency difference in the two directions of the calculated frequency deviation ΔF—the open and closed directions of the guide vane—is calculated. When the frequency is higher than the upper dead zone, the guide vane is closed; when the frequency is lower than the lower dead zone, the guide vane is open. An additional, unconditional θ is added, thereby increasing the magnitude of |ΔF|.

[0063] When ΔF < ΔF', it is considered that the dead zone has been entered, and frequency modulation is performed; if ΔF' > E... f Then ΔF = ΔF' - E f +θ, at this point the system is at high frequency, and a frequency modulation action is performed;

[0064] If ΔF' < -E f Then ΔF=ΔF'-(-E) f )+(-θ)=ΔF+E f -θ, at this point the system is at a low frequency, and a frequency adjustment action is performed;

[0065] If -(E f -0.01)≤ΔF'≤E f If the value is -0.01, then ΔF = 0, and a frequency modulation recovery is performed, increasing the hysteresis by 0.01Hz.

[0066] Where θ is confined to (0, E) f Within a certain range, the compensation requirements for different actual action amounts of the guide vane opening are adapted, and θ is generally taken in the range of (0, 0.1Hz).

[0067] After ΔF, a delay filter T is added to monitor the grid frequency deviation ΔF in real time. When ΔF is less than X, the timing delay begins. When the delay satisfies T∈[x,y], where in this invention, T∈[0.2s,1s], it prevents the frequency from frequently crossing the dead zone edge or the frequency measurement itself from fluctuating, causing frequent operation of the speed controller. The frequency difference is adjusted and PID calculation is performed to obtain the guide vane setpoint change, preventing a frequency regulation malfunction caused by a brief fluctuation in the system frequency or a frequency measurement error.

[0068] S2: Optimize and adaptively adjust the superposition amount and delay, and perform prediction and multi-level frequency modulation during a single frequency modulation operation.

[0069] Furthermore, by monitoring the system's frequency deviation in real time and analyzing and modeling the system's historical data, an adaptive control algorithm is used to adjust the superposition amount and delay element. The adaptive rate is:

[0070] u(t) = u(t-1) + Δu(t)

[0071] Δu(t)=e(t)*ε

[0072] e(t) = r(t) - y(t)

[0073] Where Δu(t) is the adjustment amount calculated based on the error function and the adaptive law, r(t) is the output of the reference model, y(t) is the output of the actual system, e(t) is the error function, and ε is the adaptive law coefficient.

[0074] It should be noted that in a single frequency modulation operation, a multi-level frequency modulation strategy is implemented. Based on the magnitude of the frequency deviation ΔF, the current frequency modulation levels are determined as: Level 1, Level 2, and Level 3. Based on the current frequency modulation level n, the corresponding frequency modulation action is selected and executed.

[0075] ΔP f =K n *Δf

[0076] Where, ΔP f Let K be the frequency modulation input, K be the frequency modulation coefficient, n be the frequency modulation level (n = 1, 2, 3), and Δf be the frequency difference signal. By introducing a multi-level frequency modulation strategy, an appropriate frequency modulation action can be selected based on the magnitude of the frequency deviation, thereby improving the flexibility and response speed of frequency modulation.

[0077] It should also be noted that in a single frequency modulation operation, the predictive control algorithm predicts the trend of system frequency changes in advance: a predictive model is established based on the current system state and historical data.

[0078]

[0079] in, ω is the autoregressive coefficient. n ΔF'(t) and ΔF'(h) are the current system frequency modulation deviation and the historical system frequency modulation deviation given by the system, respectively, and ΔF(t) and ΔF(h) are the calculated current system frequency modulation deviation and the historical system frequency modulation deviation.

[0080] Based on the prediction model, the trend of system frequency change is predicted, and the guide vane is adjusted accordingly: if Δf(t) exceeds the prediction threshold, it indicates that the system frequency will rise, so the guide vane opening is increased to increase the system's power generation; if Δf(t) is less than the prediction threshold, it indicates that the system frequency will fall, so the guide vane opening is decreased to reduce the system's power generation.

[0081] S3: Add a hysteresis circuit when performing a single frequency recovery process.

[0082] Furthermore, in a frequency modulation recovery stage, a hysteresis stage is added: when -(E f -0.01)≤ΔF'≤E f When the frequency is -0.01 Hz, ΔF = 0, and a frequency regulation reset is performed, increasing the hysteresis by 0.01 Hz. If the reset condition is not met, the frequency regulation action is waited for execution. This serves two purposes: First, it prevents frequent adjustments during reset and operation when the grid system frequency crosses the dead zone edge, which could lead to severe oscillations in the guide vane opening and abnormal power fluctuations. Second, adding a hysteresis condition to the reset condition makes it less prone to reset, allowing for more thorough primary frequency regulation and a larger guide vane operation, which is beneficial for assessing integrated power.

[0083] Example 2

[0084] Reference Figures 1-7 As an embodiment of the present invention, an improved method for overcoming the mechanical dead zone of frequency regulation in a water turbine governor is provided. In order to verify the beneficial effects of the present invention, scientific demonstration is carried out through experiments.

[0085] The test was conducted according to the calculation method in Example 1, and the results are as follows:

[0086] 1. The system frequency setpoint is 50Hz, the actual system frequency is 50.1Hz, and the frequency deviation ΔF' is 0.1Hz.

[0087] After one frequency modulation operation, through the dead zone Ef (0.05Hz) stage, the frequency deviation ΔF = θ = 0.05Hz.

[0088] Multi-stage frequency modulation strategy: single-stage frequency modulation, with a guide vane setpoint variation of (0.05 / 50) / 4%.

[0089] Predictive control frequency modulation: The system frequency is predicted to increase, and the guide vane setpoint is increased by 0.05Hz.

[0090] 2. The system frequency setpoint is 50Hz, the actual system frequency is 49.9Hz, and the frequency deviation ΔF' is -0.1Hz.

[0091] After one frequency modulation operation, through the dead zone Ef (0.05Hz), the frequency deviation ΔF = -θ = -0.05Hz.

[0092] Multi-stage frequency modulation strategy: two-stage frequency modulation, with a guide vane setpoint change of (-0.05 / 50) / 4%.

[0093] Predictive control frequency modulation: It is predicted that the system frequency will decrease, and the guide vane setpoint will be reduced by 0.05Hz.

[0094] 3. The system frequency setpoint is 50Hz, the actual system frequency is 50.05Hz, and the frequency deviation ΔF' is 0.05Hz.

[0095] After one frequency modulation reset, the frequency deviation ΔF = 0.

[0096] Multi-level frequency modulation strategy: Not applicable.

[0097] Predictive control frequency modulation: Not applicable.

[0098] 4. The system frequency setpoint is 50Hz, the actual system frequency is 49.95Hz, and the frequency deviation ΔF' is -0.05Hz.

[0099] After one frequency modulation reset, the frequency deviation ΔF = 0.

[0100] Multi-level frequency modulation strategy: Not applicable.

[0101] Predictive control frequency modulation: Not applicable.

[0102] The system frequency setpoint is 50Hz, the actual system frequency is 50.15Hz, and the frequency deviation ΔF' is 0.15Hz.

[0103] 5. After one frequency modulation operation, after the dead zone Ef (0.05Hz), the frequency deviation ΔF = θ = 0.1Hz.

[0104] Multi-stage frequency modulation strategy: three-stage frequency modulation, with a guide vane setpoint variation of (0.1 / 50) / 4%.

[0105] Predictive control frequency modulation: The system frequency is predicted to increase, and the guide vane setpoint will increase by 0.1 Hz.

[0106] 6. The system frequency setpoint is 50Hz, the actual system frequency is 49.85Hz, and the frequency deviation ΔF' is -0.15Hz.

[0107] After one frequency modulation operation, through the dead zone Ef (0.05Hz) stage, the frequency deviation ΔF = -θ = -0.1Hz.

[0108] Multi-stage frequency modulation strategy: two-stage frequency modulation, with a guide vane setpoint variation of (0.1 / 50) / 4%.

[0109] Predictive control frequency modulation: It is predicted that the system frequency will decrease, and the guide vane setpoint will decrease by 0.1 Hz.

[0110] 7. The system frequency setpoint is 50Hz, the actual system frequency is 50.2Hz, and the frequency deviation ΔF' is 0.2Hz.

[0111] After one frequency modulation operation, through the dead zone Ef (0.05Hz) stage, the frequency deviation ΔF = θ = 0.15Hz.

[0112] Multi-stage frequency modulation strategy: three-stage frequency modulation, with a guide vane setpoint variation of (0.15 / 50) / 4%.

[0113] Predictive control frequency modulation: The system frequency is predicted to increase, and the guide vane setpoint will increase by 0.15Hz.

[0114] 8. The system frequency setpoint is 50Hz, the actual system frequency is 49.7Hz, and the frequency deviation ΔF' is -0.2Hz.

[0115] After one frequency modulation operation, through the dead zone Ef (0.05Hz) stage, the frequency deviation ΔF = -θ = -0.15Hz.

[0116] Multi-stage frequency modulation strategy: single-stage frequency modulation, with a guide vane given change of (-0.15 / 50) / 4%.

[0117] Predictive control frequency modulation: The system frequency is predicted to decrease, and the guide vane setpoint is reduced by 0.15Hz.

[0118] 9. The system frequency setpoint is 50Hz, the actual system frequency is 50.3Hz, and the frequency deviation ΔF' is 0.3Hz.

[0119] After one frequency modulation operation, through the dead zone Ef (0.05Hz) stage, the frequency deviation ΔF = θ = 0.2Hz.

[0120] Multi-stage frequency modulation strategy: three-stage frequency modulation, with guide vane setpoint variation of (0.2 / 50) / 4%.

[0121] Predictive control frequency modulation: The system frequency is predicted to increase, and the guide vane setpoint will increase by 0.2 Hz.

[0122] 10. The system frequency setpoint is 50Hz, the actual system frequency is 49.6Hz, and the frequency deviation ΔF' is -0.3Hz.

[0123] After one frequency modulation operation, through the dead zone Ef (0.05Hz), the frequency deviation ΔF = -θ = -0.2Hz.

[0124] Multi-stage frequency modulation strategy: two-stage frequency modulation, with guide vane setpoint variation of (-0.2 / 50) / 4%.

[0125] Predictive frequency control: The system frequency is predicted to decrease, and the guide vane setpoint is reduced by 0.2Hz. The deviation ΔF' between the system frequency setpoint and the actual system frequency: This data can be used to assess the stability and accuracy of the system frequency. A large deviation indicates potential large fluctuations or measurement errors in the system frequency. By increasing a value of θ, the frequency deviation ΔF is increased, thereby increasing the magnitude of |ΔF|. This allows for more precise adjustment of the guide vane opening, improving the system's regulation capability. Based on the magnitude of the frequency deviation, the appropriate frequency regulation level is selected for adjustment, enabling more precise control of the guide vane opening to adapt to different frequency deviations. The amplitude of the guide vane setpoint change is determined based on the results of primary frequency regulation and multi-level frequency regulation strategies. This controls the change in guide vane opening, thus affecting the system's power generation. By predicting the system frequency change trend through a predictive model and adjusting the guide vane setpoint accordingly, changes in system frequency can be anticipated in advance, allowing for appropriate adjustments and improving the system's response speed and stability.

[0126] Compared with existing technologies, the above data and conclusions demonstrate an improved frequency regulation strategy. By adding the θ value and hysteresis loop after a single frequency regulation action, the system's regulation capability and stability can be improved. Simultaneously, employing a multi-stage frequency regulation strategy and predictive control frequency regulation methods allows for more precise control of the guide vane opening, adapting to different frequency deviation requirements, and anticipating system frequency change trends to make corresponding adjustments. These improvements can enhance the operating efficiency and stability of the power system.

[0127] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

[0128] Example 3

[0129] The third embodiment of the present invention differs from the first two embodiments in that:

[0130] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0131] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device.

[0132] More specific examples of computer-readable media (a non-exhaustive list) include: electrical connections (electronic devices) having one or more wires, portable computer disk drives (magnetic devices), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Furthermore, computer-readable media can even be paper or other suitable media on which the program can be printed, because the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in computer memory.

[0133] It should be understood that various parts of the present invention can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0134] Example 4

[0135] Reference Figure 8 This is the fourth embodiment of the present invention. This embodiment provides an improved system for a turbine governor to overcome the mechanical dead zone of frequency regulation, including a superposition adjustment module, a prediction and optimization module, a hysteresis module, and a delay module.

[0136] The superposition adjustment module improves the artificial failure zone unit of primary frequency regulation by adding a frequency superposition, thereby increasing the electrical output at the moment the primary frequency regulation action begins. This overcomes the dead zone and inertia of the mechanical and hydraulic links, increases the guide vane opening to deepen the change of the guide vanes, avoids the power plant's primary frequency regulation being assessed by the power grid, increases the contribution of primary frequency regulation, and facilitates the precise frequency control of the power grid.

[0137] The prediction and optimization module provides adjustment strategies for the turbine governor by predicting the grid load over a future period, maintaining a stable operating state when the grid load changes, and optimizing the superposition and delay of the turbine governor according to the changes in grid load.

[0138] The hysteresis module adds a hysteresis stage to the first frequency recovery process, meaning the hysteresis dead zone is less than the frequency dead zone, which is less than 0.01Hz.

[0139] When the frequency is adjusted, the delay module adds a delay filter to prevent frequent adjustments caused by frequency jitter and mismeasurement, so that the output signal of the speed controller can be smoothly transitioned.

[0140] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. An improved method for overcoming the mechanical dead zone of frequency regulation in a turbine governor, characterized in that: include, An improvement is made to the artificial failure zone unit of primary frequency modulation, when the frequency deviation ΔF′ exceeds the frequency dead zone E. f Then, a superposition amount is added to the calculated frequency deviation ΔF, and a delay filtering stage is added when a frequency modulation action is performed; The superposition amount and delay are optimized and adaptively adjusted, and prediction and multi-level frequency modulation are performed during a single frequency modulation operation; When performing a single frequency recovery process, a hysteresis circuit is added.

2. The improved method for overcoming the mechanical dead zone of frequency regulation in a turbine governor as described in claim 1, characterized in that: The increased superposition amount includes when the deviation ΔF′ between the given frequency and the system frequency exceeds the artificial failure zone E. f Then, the frequency difference in the two directions of the calculated frequency deviation ΔF—the open and closed directions of the guide vane—is calculated. When the frequency is higher than the upper dead zone, the guide vane is closed; when the frequency is lower than the lower dead zone, the guide vane is open. An additional, unconditional θ is added, thereby increasing the magnitude of |ΔF|. When ΔF < ΔF′, it is considered that the dead zone has been entered, and frequency modulation is performed; if ΔF′ > E, it is considered that the dead zone has been entered. f Then ΔF=ΔF′-E f +θ, at this point the system is at high frequency, and a frequency modulation action is performed; If ΔF′<-E f Then ΔF=ΔF′-(-E) f )+(-θ)=ΔF+E f -θ, at this point the system is at a low frequency, and a frequency adjustment action is performed; Where θ is confined to (0, E) f It can adapt to different compensation requirements for different actual actuation amounts of guide vane opening within a certain range.

3. An improved method for overcoming the mechanical dead zone of frequency regulation in a turbine governor as described in claim 2, characterized in that: The added hysteresis stage includes adding a hysteresis stage during the first frequency modulation recovery stage: when -(E f -0.01)≤ΔF′≤E f When the value is -0.01, ΔF = 0, and a frequency modulation reset is performed, increasing the hysteresis by 0.01Hz. If the reset condition is not met, the process waits to execute the frequency modulation action.

4. An improved method for overcoming the mechanical dead zone of frequency regulation in a turbine governor as described in claim 3, characterized in that: The added delay filtering stage includes adding a delay filtering stage T after ΔF, which monitors the power grid frequency deviation ΔF in real time. When ΔF is less than X, the timing delay begins. When the delay satisfies T∈[x,y], the frequency difference is adjusted and PID calculation is performed to obtain the guide vane given change.

5. An improved method for overcoming the mechanical dead zone of frequency regulation in a turbine governor as described in claim 4, characterized in that: The adaptive adjustment of the superposition amount and delay element includes real-time monitoring of the system's frequency deviation, analysis and modeling of historical system data, and adjustment of the superposition amount and delay element through an adaptive control algorithm. The adaptive rate is: u(t) = u(t-1) + Δu(t) Δu(t)=e(t)*ε e(t) = r(t) - y(t) Where Δu(t) is the adjustment amount calculated based on the error function and the adaptive law, r(t) is the output of the reference model, y(t) is the output of the actual system, e(t) is the error function, and ε is the adaptive law coefficient.

6. An improved method for overcoming the mechanical dead zone of frequency regulation in a turbine governor as described in claim 5, characterized in that: The multi-level frequency modulation includes implementing a multi-level frequency modulation strategy within a single frequency modulation action. Based on the magnitude of the frequency deviation ΔF, the current frequency modulation levels are determined as: Level 1, Level 2, and Level 3. Based on the current frequency modulation level n, the corresponding frequency modulation action is selected and executed. ΔP f =K n *Δf Where, ΔP f Δf is the frequency modulation quantity, K is the frequency modulation coefficient, n is the frequency modulation level (n = 1, 2, 3), and Δf is the frequency difference signal.

7. An improved method for overcoming the mechanical dead zone of frequency regulation in a turbine governor as described in claim 6, characterized in that: The predictive control frequency modulation includes, during a single frequency modulation operation, using a predictive control algorithm to predict the trend of system frequency changes in advance: a predictive model is established based on the current system state and historical data. in, ω is the autoregressive coefficient. n ΔF′(t) and ΔF′(h) are the current system frequency modulation deviation and the historical system frequency modulation deviation given by the system, respectively, and ΔF(t) and ΔF(h) are the calculated current system frequency modulation deviation and the historical system frequency modulation deviation. Based on the prediction model, the trend of system frequency change is predicted, and the guide vane is adjusted accordingly: if Δf(t) exceeds the prediction threshold, it indicates that the system frequency will rise, so the guide vane opening is increased to increase the system's power generation; if Δf(t) is less than the prediction threshold, it indicates that the system frequency will fall, so the guide vane opening is decreased to reduce the system's power generation.

8. A system employing an improved method for overcoming the mechanical dead zone of a turbine governor as described in any one of claims 1 to 7, characterized in that: It includes a superposition adjustment module, a prediction and optimization module, a hysteresis module, and a delay module; The superposition adjustment module improves the artificial failure zone unit of primary frequency regulation by adding a frequency superposition, thereby increasing a larger electrical output at the moment the primary frequency regulation action begins. This overcomes the dead zone and inertia of the mechanical and hydraulic links, increases the guide vane opening to deepen the change of the guide vanes, avoids the power plant's primary frequency regulation being assessed by the power grid, increases the contribution of primary frequency regulation, and facilitates the precise frequency control of the power grid. The prediction and optimization module provides adjustment strategies for the turbine governor by predicting the grid load over a future period, maintaining a stable operating state when the grid load changes, and optimizing the superposition amount and delay of the turbine governor according to the changes in grid load. The hysteresis module adds a hysteresis stage to the frequency recovery process, meaning the hysteresis dead zone is less than the frequency dead zone and less than 0.01Hz. The delay module adds a delay filter during a frequency modulation operation to prevent frequent adjustments caused by frequency jitter and mismeasurement, thus ensuring a smooth transition of the speed controller's output signal.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 7.

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