Turbine speed control system monitoring and energy regulation method based on hydraulic servo state quantity fusion

Abstract

This invention relates to the technical field of steam turbine control, and particularly to a monitoring and energy regulation method for a steam turbine speed control system based on hydraulic servo state quantity fusion. The method includes: segmenting the system based on the sequential relationship between the hydraulic actuator pressure state and the valve displacement state to form a hysteresis loop segment index, facilitating the location of hysteresis; generating hydraulic hysteresis state tags by comparing the hysteresis loop segment index with a reference hysteresis loop index to distinguish abnormal types such as start-up hysteresis, servo jamming, position leakage, and return friction; further generating energy regulation quantities by combining the power response position after valve displacement, allowing the hysteresis identification results to be directly converted into opening limit, valve position holding, or load correction; and finally, adjusting the valve opening command or unit load command by the steam turbine speed controller to reduce load fluctuations and valve over-adjustment caused by hydraulic hysteresis, thereby improving speed regulation stability.

Description

Technical Field

[0001] This invention relates to the technical field of steam turbine control, and in particular to a monitoring and energy regulation method for a steam turbine speed control system based on the fusion of hydraulic servo state variables. Background Technology

[0002] During the hydraulic servo regulation of the high-pressure regulating valve of a grid-connected steam turbine generator unit, the turbine speed controller outputs a regulating valve opening command based on the unit load command or primary frequency regulation requirement. The electro-hydraulic servo valve changes the pressure state of the hydraulic actuator, which in turn pushes the high-pressure regulating valve to produce a valve displacement. The change in the high-pressure regulating valve opening further alters the steam inlet to the turbine and causes changes in the unit's active power state. Due to factors such as zero bias of the electro-hydraulic servo valve, oil circuit leakage of the hydraulic actuator, increased valve stem friction, delayed valve position feedback, and fluctuations in fire-resistant oil pressure, it is possible that the hydraulic actuator pressure has entered the pressurization state while the regulating valve position is still low. Hydraulic servo hysteresis phenomena include situations where the valve displacement state remains unchanged, the valve position has entered a holding state while the hydraulic actuator pressure state continues to fluctuate, and the valve displacement state has entered a reducing opening state while the hydraulic actuator pressure state has not been depressurized in time. Traditional speed control monitoring often relies on valve position deviation, valve opening feedback, and sudden changes in downstream pressure or load to make judgments. It is difficult to distinguish whether the hysteresis occurs during pressure start-up, displacement follow-up, valve position holding, or pressure return based on the sequential relationship between the changes in hydraulic actuator pressure state and valve displacement state. Therefore, it is difficult to accurately correlate the location of hydraulic hysteresis with subsequent abnormal power response.

[0003] For example, CN115773158A discloses a method for detecting and locating valve faults in steam turbines. This method collects historical data related to regulating valves under normal operating conditions of the unit. Based on comprehensive flow commands, actual flow through the valves, and feedback values ​​of each valve opening, it obtains valve flow characteristic curves and valve opening characteristic curves. It then determines the valve fault type and location based on the linearity, dispersion, and dispersion of the flow characteristics and valve opening characteristics. However, the key technical aspect of this method lies in judging valve faults based on the dispersion of valve flow characteristics and valve opening characteristics. It fails to classify the hydraulic actuator pressure state into pressure-increasing, pressure-reducing, pressure-bearing, and pressure-relief states, nor does it classify the valve displacement state into increased opening, decreased opening, and holding states. Furthermore, it does not generate a hysteresis loop segment index based on the sequential relationship between the hydraulic actuator pressure state and the valve displacement state. Therefore, the method disclosed in CN115773158A still suffers from problems such as difficulty in subdividing the hydraulic actuator hysteresis stage and a disconnect between valve fault judgment and speed control adjustment when monitoring the hydraulic servo hysteresis of high-pressure regulating valves in grid-connected steam turbine generator units.

[0004] For example, CN104330260A discloses a fault diagnosis method for sudden load changes in turbine sequence valves based on high-pressure valve opening and closing tests. This method addresses sudden load changes caused by hardware or software faults in the high-pressure valve during sequence valve operation. It uses high-pressure valve opening and closing tests, valve stem actuation observation, load change phenomenon analysis, and high-pressure valve flow characteristic curve verification to determine the causes of faults such as software faults, hardware faults, system jamming, valve head detachment, or loose connections. However, this method relies on high-pressure valve opening and closing tests and the diagnostic process after a sudden load change; its technical focus is on the fault diagnosis. The testing and cause localization did not compare the pressure start-up segment, displacement follow-up segment, valve position holding segment, and pressure return segment during the normal operation of the turbine speed control system. Nor did it combine the hydraulic hysteresis status label with the power response position after the valve displacement to generate the opening limit, valve position holding amount, or load correction amount. Therefore, the method disclosed in CN104330260A still has the problem of relying on the test condition for diagnosis and difficulty in online adjustment of power response abnormalities caused by hydraulic hysteresis under the peak shaving and frequency regulation conditions of the unit.

[0005] Given that existing turbine valve fault detection technologies suffer from problems such as overemphasizing valve flow characteristic diagnosis, overemphasizing high-pressure valve test diagnosis, lacking segmented identification of the hydraulic hysteresis process between the hydraulic actuator pressure state and the valve displacement state, and difficulty in directly converting hysteresis identification results into load regulation quantities, this invention proposes a turbine speed control system monitoring and energy regulation method based on hydraulic servo state quantity fusion. This method solves the problem of how to segmented identification of the hysteresis stage between the hydraulic actuator pressure state and the valve displacement state in the high-pressure valve hydraulic servo hysteresis scenario, and how to convert the hysteresis identification results into speed control quantities. Summary of the Invention

[0006] The purpose of this section is to outline some aspects of the embodiments of the present invention and to briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section, as well as in the abstract and title of the present application, to avoid obscuring the purpose of this section, the abstract and title of the invention. Such simplifications or omissions shall not be used to limit the scope of the present invention.

[0007] In view of the aforementioned existing problems, the present invention is proposed.

[0008] To solve the above-mentioned technical problems, the present invention provides the following technical solution: As a preferred embodiment of the monitoring and energy regulation method for a turbine speed control system based on hydraulic servo state fusion described in this invention, wherein: the turbine speed control system is divided into segments according to the sequential relationship between the change of hydraulic motor pressure state and valve displacement state, and a hysteresis loop segment index is generated. The hysteresis loop fragment index is compared with the baseline hysteresis loop index formed based on the healthy operating conditions to generate hydraulic hysteresis state labels. Based on the power response position of the hydraulic hysteresis state label after the valve displacement, an energy adjustment amount is generated; The energy regulation amount is sent to the turbine speed controller, which then adjusts the valve opening command or the unit load command.

[0009] The beneficial effects of this invention are as follows: This invention divides the hydraulic hysteresis process into segments based on the sequential relationship between the hydraulic actuator pressure state and the valve displacement state, forming a hysteresis loop segment index. This allows the hydraulic hysteresis process to be divided into stages such as pressure start-up, displacement follow-up, valve position holding, and pressure return, facilitating the location of hysteresis occurrence. By comparing the hysteresis loop segment index with the reference hysteresis loop index, a hydraulic hysteresis state label is generated, which can distinguish abnormal types such as start-up hysteresis, follow-up jamming, stabilization leakage, and return friction. Furthermore, by combining the power response position after valve displacement, an energy adjustment amount is generated, allowing the hysteresis identification result to be directly converted into opening limit, valve position holding, or load correction. Finally, the turbine speed controller adjusts the valve opening command or unit load command, reducing load fluctuations and valve over-adjustment caused by hydraulic hysteresis and improving speed regulation stability. Attached Figure Description

[0010] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein: Figure 1 This is a flowchart illustrating the monitoring and energy regulation method for a steam turbine speed control system based on hydraulic servo state quantity fusion, as shown in this invention. Detailed Implementation

[0011] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0012] Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without inventive effort should fall within the scope of protection of this invention.

[0013] 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.

[0014] According to an embodiment of the present invention, in combination Figure 1 The flowchart shown illustrates a monitoring and energy regulation method for a steam turbine speed control system based on hydraulic servo state variable fusion, which specifically includes the following steps: S1. Based on the sequential relationship between the hydraulic actuator pressure state and the valve displacement state in the turbine speed control system, the system is segmented to generate a hysteresis loop segment index. Note that the following should be noted in this step: S1.1 Divide the hydraulic actuator pressure state into pressure increase state, pressure decrease state, pressure bearing state and pressure relief state, and divide the valve displacement state into opening increase state, opening decrease state and holding state. Arrange the hydraulic actuator pressure state and valve displacement state in a one-to-one correspondence according to the sampling point number to form a hydraulic actuator pressure-valve displacement state sequence. S1.2 In the hydraulic actuator pressure-valve displacement state sequence, the section where the hydraulic actuator pressure state changes from the pressurized state or the depressurized state to the pressurized state and the valve displacement state is in the holding state is divided into pressure start segment; the section where the hydraulic actuator pressure state is in the pressurized state and the valve displacement state changes from the holding state to the open state is divided into displacement follow-up segment; the section where the valve displacement state is in the holding state and the hydraulic actuator pressure state switches between the pressurized state and the pressurized state is divided into valve position holding segment; the section where the valve displacement state changes from the holding state to the open state and the hydraulic actuator pressure state changes from the pressurized state to the depressurized state is divided into pressure return segment; S1.3 Generate a hysteresis loop segment index according to the arrangement order of pressure start segment, displacement follow-up segment, valve position holding segment and pressure return segment.

[0015] In a preferred embodiment, the method is applied to the scenario of monitoring and regulating the hydraulic servo hysteresis of the high-pressure regulating valve of a grid-connected steam turbine generator set. In this embodiment, the turbine speed control system is a digital electro-hydraulic regulation system, and the regulating valve is the high-pressure regulating valve of the steam turbine, specifically the high-pressure regulating valve that regulates the entry of high-pressure steam into the high-pressure cylinder of the steam turbine. The pressure state of the hydraulic actuator is derived from the pressure transmitter of the hydraulic actuator inlet chamber or control chamber corresponding to the high-pressure regulating valve. The pressure transmitter is installed on the side of the hydraulic actuator hydraulic pipeline close to the hydraulic actuator cylinder body, and the hydraulic actuator pressure sampling value is in MPa. The valve displacement state is derived from the valve position feedback device connected to the high-pressure regulating valve stem. The valve position feedback device adopts a linear displacement sensor or a valve position encoder, and the valve displacement sampling value is expressed as a percentage of the full stroke of the regulating valve. The hydraulic actuator pressure sampling value and the regulating valve displacement sampling value are obtained by the same digital electro-hydraulic regulation system according to the same sampling point number. In this embodiment, the interval between adjacent sampling points is 20ms, and each sampling point number corresponds to one hydraulic actuator pressure sampling value and one regulating valve displacement sampling value.

[0016] Specifically, the pressure states of the hydraulic actuator are divided into pressure-increasing state, pressure-reducing state, pressure-bearing state, and pressure-relieving state, including: Obtain the hydraulic motor pressure sampling values ​​of the same valve at two adjacent sampling points, and calculate the pressure difference formed by the hydraulic motor pressure sampling value of the later sampling point relative to the hydraulic motor pressure sampling value of the previous sampling point; When the pressure difference is positive and the pressure difference is greater than the pressure change dead zone, the oil motor pressure state of the next sampling point is classified as the pressure rise state. The pressure change dead zone is determined by the allowable fluctuation of the oil motor pressure in the steady-state load test of the turbine speed control system. When the pressure difference is negative, the absolute value of the pressure difference is greater than the pressure change dead zone, and the hydraulic motor pressure sampling value of the next sampling point is between the lower pressure limit and the upper pressure limit, the hydraulic motor pressure state of the next sampling point is classified as a pressure reduction state. When the hydraulic motor pressure sampling value at the next sampling point is between the lower pressure limit and the upper pressure limit, and the absolute value of the pressure difference is not greater than the pressure change dead zone, the hydraulic motor pressure state at the next sampling point is classified as a pressure state. When the hydraulic motor pressure sample value at the next sampling point is less than the lower pressure limit and the pressure difference is negative, the hydraulic motor pressure state at the next sampling point is classified as a depressurization state. The lower pressure limit is the minimum hydraulic motor pressure required to keep the valve displacement constant, and the upper pressure limit is the maximum hydraulic motor pressure required to keep the valve displacement constant without causing the valve to open further.

[0017] Furthermore, the valve displacement state is divided into three states: increasing opening, decreasing opening, and holding, including: Obtain the valve displacement sampling values ​​of the same valve at two adjacent sampling points, and calculate the displacement difference formed by the valve displacement sampling value of the later sampling point relative to the valve displacement sampling value of the previous sampling point; When the displacement difference is positive and the displacement difference is greater than the displacement change dead zone, the valve displacement state of the next sampling point is divided into an increased opening state. The displacement change dead zone is determined by the larger of the displacement resolution of the valve position feedback device and the allowable valve position jitter during steady-state operation of the turbine speed control system. When the displacement difference is negative and the absolute value of the displacement difference is greater than the displacement change dead zone, the valve displacement state of the next sampling point is classified as the reduced opening state. When the absolute value of the displacement difference is not greater than the displacement change dead zone, the valve displacement state of the next sampling point is classified as a holding state.

[0018] In this embodiment, the sequence of changes refers to the sequential relationship between the change in hydraulic actuator pressure and the change in valve displacement during the same high-pressure valve operation, based on the sampling point numbers. Specifically, during normal hydraulic servo operation, after the high-pressure valve receives an adjustment request to increase its opening direction, the hydraulic actuator pressure first changes from the pressure-bearing range to the pressure-increasing direction, and then the valve displacement changes from the holding state to the increasing opening state. When the valve enters the vicinity of the target opening, the hydraulic actuator pressure returns to the pressure-bearing range, and the valve displacement enters the holding state. When the high-pressure valve receives an adjustment request to decrease its opening direction, the hydraulic actuator pressure changes from the pressure-bearing range to the pressure-reducing direction, and then the valve displacement changes from the holding state to the decreasing opening state. In this embodiment, the sequence of changes is not based solely on comparing pressure magnitude or valve position size, but rather on comparing the sampling point positions where the hydraulic actuator pressure changes and the sampling point positions where the valve displacement changes, using the sampling point numbers as a reference.

[0019] In this embodiment, the lower pressure limit is taken as 9.60 MPa and the upper pressure limit is taken as 10.20 MPa. The lower and upper pressure limits are obtained by a steady-state load test of the high-pressure control valve at around 50% opening. Specifically, under the conditions of unit grid connection, load of 70% of rated load, main steam pressure fluctuation not exceeding 0.20 MPa, and no step change in control valve opening command for 10 minutes, the hydraulic actuator pressure range when the displacement change of the high-pressure control valve stem does not exceed 0.15% of the full stroke is recorded; the lowest pressure that can maintain the control valve displacement without decreasing is taken as the lower pressure limit, and the highest pressure that does not cause the control valve to continue to open is taken as the upper pressure limit.

[0020] In this embodiment, the pressure change dead zone is set to 0.06 MPa. The pressure change dead zone is determined by the maximum allowable fluctuation of the hydraulic actuator pressure within 10 minutes during the steady-state load test. When the hydraulic actuator pressure fluctuation is between 0.04 MPa and 0.06 MPa during the steady-state load test, 0.06 MPa is used as the pressure change dead zone in this embodiment to eliminate the influence of pressure transmitter noise and small pulsations in the hydraulic pipeline on the state division.

[0021] In this embodiment, the displacement resolution of the valve position feedback device is 0.05% of the full stroke, the allowable valve position jitter during steady-state operation of the turbine speed control system is 0.12% of the full stroke, and the displacement change dead zone is 0.12% of the full stroke. Therefore, when the valve displacement change between adjacent sampling points is greater than 0.12% of the full stroke and the change direction is the opening direction, the valve displacement state of the next sampling point is the opening state; when the valve displacement change between adjacent sampling points is greater than 0.12% of the full stroke and the change direction is the closing direction, the valve displacement state of the next sampling point is the closing state; when the valve displacement change between adjacent sampling points is not greater than 0.12% of the full stroke, the valve displacement state of the next sampling point is the holding state.

[0022] When forming the hydraulic actuator pressure-valve displacement state sequence, each sampling point number includes both the hydraulic actuator pressure state and the valve displacement state. For example, sampling point number 1001 corresponds to a hydraulic actuator pressure sampling value of 9.82 MPa and a valve displacement sampling value of 38.10% of the full stroke, while sampling point number 1002 corresponds to a hydraulic actuator pressure sampling value of 9.90 MPa and a valve displacement sampling value of 38.12% of the full stroke. Since the pressure difference is greater than 0.06 MPa and the displacement difference is not greater than 0.12% of the full stroke, the hydraulic actuator pressure state corresponding to sampling point number 1002 is in the boosting state, and the valve displacement state is in the holding state. After processing consecutive sampling points in the same way, the hydraulic actuator pressure-valve displacement state sequence arranged by sampling point number is obtained.

[0023] It should be noted that the pressure initiation segment, displacement follow-up segment, valve position holding segment, and pressure return segment are all composed of continuous sampling points. Specifically, the starting position of the pressure initiation segment is the first sampling point where the hydraulic actuator pressure changes from a pressurized or depressurized state to a pressurized state, and the ending position of the pressure initiation segment is the sampling point before the valve displacement first changes from a holding state to a partially open state. If the hydraulic actuator pressure has already increased, but the valve displacement is still in a holding state, this segment reflects the initiation stage where hydraulic pressure has been established but the valve stem has not yet followed the movement. The starting position of the displacement follow-up segment is the first sampling point where the valve displacement changes from a holding state to a partially open state. The termination position of the displacement follow-up segment is the sampling point before the valve displacement state returns to the holding state; the starting position of the valve position holding segment is the first sampling point when the valve displacement state returns to the holding state, and the ending position of the valve position holding segment is the sampling point before the valve displacement state leaves the holding state; within this segment, the hydraulic actuator pressure can switch between the pressure-bearing state and the pressure-boosting state; the starting position of the pressure return segment is the first sampling point when the valve displacement state changes from the holding state to the de-opening state and the hydraulic actuator pressure state changes from the pressure-bearing state to the pressure-relief state, and the ending position of the pressure return segment is the sampling point before the valve displacement state returns to the holding state.

[0024] Specifically, the hysteresis loop segment index generated in step S1 includes the segment name, starting sampling point number, ending sampling point number, pressure state arrangement within the segment, displacement state arrangement within the segment, pressure start value, pressure end value, displacement start value, and displacement end value. For example, the pressure start segment corresponds to sampling point numbers 1002 to 1007, the displacement follow-up segment corresponds to sampling point numbers 1008 to 1020, the valve position holding segment corresponds to sampling point numbers 1021 to 1045, and the pressure return segment corresponds to sampling point numbers 1046 to 1060. The hysteresis loop segment index is generated in the above order.

[0025] Preferably, this embodiment converts the originally continuously changing pressure sampling values ​​and valve position sampling values ​​in the hydraulic servo action of the high-pressure regulating valve into hysteresis loop segment indexes with clear boundaries, thus solving the problem of lacking comparable segment boundaries between the hydraulic actuator pressure changes and the regulating valve displacement changes. By defining the state through pressure change dead zone, displacement change dead zone, lower pressure limit, and upper pressure limit, the interference of steady-state pressure pulsation and valve position feedback jitter on state division can be reduced, so that subsequent hysteresis identification does not rely on single-point outliers, thereby improving the stability of high-pressure regulating valve hydraulic servo hysteresis monitoring.

[0026] S2. Compare the hysteresis loop segment index with the baseline hysteresis loop index formed based on healthy operating conditions, and generate hydraulic hysteresis state labels. Note that the following points should be noted in this step: S2.1. Based on the pressure start segment, displacement follower segment, valve position holding segment and pressure return segment in the hysteresis loop segment index, pair them one by one with the reference pressure start segment, reference displacement follower segment, reference valve position holding segment and reference pressure return segment in the reference hysteresis loop index to form a matching group of segments with the same name. S2.2. In the same-name segment pairing group, compare the pressure initiation segment, displacement follower segment, valve position holding segment, and pressure return segment in the hysteresis loop segment index with the reference pressure initiation segment, reference displacement follower segment, reference valve position holding segment, and reference pressure return segment in the reference hysteresis loop index, respectively, comparing their pressure change direction, displacement change direction, pressure change amplitude, and displacement change amplitude; wherein: When the pressure change of the pressure starter segment is greater than that of the reference pressure starter segment, and the displacement change of the pressure starter segment is less than that of the reference pressure starter segment, a start-up hysteresis tag is generated. When the pressure change direction of the displacement follower segment is opposite to the displacement change direction of the displacement follower segment, or when the displacement change amplitude of the displacement follower segment is less than the displacement change amplitude of the reference displacement follower segment, a follower tag is generated. When the valve position holding segment is in a holding state and the pressure change of the valve position holding segment is greater than the pressure change of the reference valve position holding segment, a stable leakage tag is generated. When the valve displacement state of the pressure return segment is in the reduced opening state, and the hydraulic pressure state of the pressure return segment has not switched to the depressurization state, a return friction tag is generated. Hydraulic hysteresis status labels include starting hysteresis label, follow-up jamming label, stabilization leakage label, and return friction label.

[0027] It should be noted that the healthy operating condition in this embodiment refers to the operating state of the high-pressure regulating valve hydraulic servo system of the grid-connected steam turbine generator unit being free from jamming, internal leakage, abnormal valve stem friction, abnormal valve position feedback, and speed regulation oil pressure alarm. Specifically, the healthy operating condition in this embodiment includes the following conditions: the unit is in grid-connected operation; the unit load is between 60% and 90% of the rated load; the main steam pressure fluctuation does not exceed 0.30 MPa; the speed regulation oil header pressure is between 13.50 MPa and 14.50 MPa; the high-pressure regulating valve position feedback deviation does not exceed 0.30% of the full stroke; after the high-pressure regulating valve increases or decreases its opening, the direction of the unit's active power change is consistent with the direction of the regulating valve displacement change; and the digital electro-hydraulic control system does not exhibit low oil motor pressure, servo valve failure, valve position feedback failure, or abnormal load fluctuation alarms.

[0028] Specifically, after the unit has undergone a hot start-up following maintenance, passed the static test of the speed control system, and stabilized the grid load, the same high-pressure control valve is selected for a step opening test and a small disturbance test. The valve opening change in the step opening test is from 1.00% to 3.00% of the full stroke, and the valve opening change in the small disturbance test is from 0.30% to 0.80% of the full stroke. For each test, the hydraulic motor pressure sampling value, control valve displacement sampling value, control valve opening command, and unit active power sampling value are recorded. After removing test segments with sudden drops in main steam pressure, grid frequency deviations exceeding 0.05Hz, or valve position feedback jumps exceeding 0.50% of the full stroke, the remaining test segments are considered healthy operating condition segments.

[0029] Furthermore, the method for forming a baseline hysteresis loop index based on healthy operating conditions includes: processing each healthy operating condition segment according to the same state division rules as S1 to form a healthy pressure start-up segment, a healthy displacement follow-up segment, a healthy valve position holding segment, and a healthy pressure return segment; aligning multiple healthy segments under the same segment name according to the length from the start sampling point to the end sampling point; obtaining the pressure change direction, displacement change direction, pressure change amplitude, and displacement change amplitude for the aligned healthy segments; and selecting the median performance as the baseline pressure start-up segment, the baseline displacement follow-up segment, the baseline valve position holding segment, and the baseline pressure return segment.

[0030] Preferably, using the median performance rather than the result of a single test as the benchmark can reduce the impact of local steam disturbances or minor drift of the pressure sensor on the benchmark during a single test.

[0031] In this embodiment, the pressure change direction refers to the direction of change of the hydraulic actuator pressure sampling value within the same segment from the segment start position to the segment end position. When the hydraulic actuator pressure sampling value at the segment end position is higher than the hydraulic actuator pressure sampling value at the segment start position and exceeds the pressure change dead zone, the pressure change direction is an increasing direction. When the hydraulic actuator pressure sampling value at the segment end position is lower than the hydraulic actuator pressure sampling value at the segment start position and exceeds the pressure change dead zone, the pressure change direction is a decreasing direction. When the difference between the two does not exceed the pressure change dead zone, the pressure change direction is a stable direction. The displacement change direction refers to the direction of change of the valve displacement sampling value within the same segment from the segment start position to the segment end position. When the valve displacement sampling value at the segment end position is higher than the valve displacement sampling value at the segment start position and exceeds the displacement change dead zone, the displacement change direction is an increasing direction. When the valve displacement sampling value at the segment end position is lower than the valve displacement sampling value at the segment start position and exceeds the displacement change dead zone, the displacement change direction is a decreasing direction. When the difference between the two does not exceed the displacement change dead zone, the displacement change direction is a constant direction.

[0032] Pressure change amplitude refers to the difference between the hydraulic motor pressure sample value at the end position of the segment and the hydraulic motor pressure sample value at the beginning position of the segment within the same segment. If there are multiple local rise and fall processes within the segment, the difference between the highest and lowest hydraulic motor pressure sample values ​​within the segment is used as the pressure change amplitude. Displacement change amplitude refers to the difference between the valve displacement sample value at the end position of the segment and the valve displacement sample value at the beginning position of the segment within the same segment. If there is reciprocating jitter within the segment, the difference between the maximum and minimum valve displacement sample values ​​within the segment is used as the displacement change amplitude.

[0033] It should also be noted that the starting hysteresis label indicates that the hydraulic actuator pressure has reached a level greater than the healthy baseline pressure build-up process, but the high-pressure valve displacement change is less than the healthy baseline displacement change. This indicates that when the high-pressure valve transitions from a stationary state to an operating state, there is an increase in starting resistance, an increase in initial valve stem friction, or insufficient low-speed creep of the hydraulic actuator. For example, if the pressure change amplitude of the pressure starting segment is 0.72 MPa, the pressure change amplitude of the reference pressure starting segment is 0.38 MPa, and the displacement change amplitude of the pressure starting segment is 0.04% of the full stroke, while the displacement change amplitude of the reference pressure starting segment is 0.18% of the full stroke, then a starting hysteresis label will be generated.

[0034] The "follow-up jamming" label indicates that during the displacement follow-up stage, the direction of change in hydraulic motor pressure is opposite to the direction of change in valve displacement, or the change in valve displacement is significantly smaller than that of the reference displacement follow-up segment. This indicates that the change in hydraulic motor pressure cannot be effectively converted into a change in valve stem displacement, which may be due to valve stem jamming, increased connecting rod friction, discontinuous servo valve output, or abnormal hydraulic motor sealing resistance. For example, if the hydraulic motor pressure continues to rise in the displacement follow-up segment, but the valve displacement only increases by 0.20% of the full stroke, while the displacement change of the reference displacement follow-up segment is 0.85% of the full stroke, then a follow-up jamming label will be generated.

[0035] A "stable position leak" label indicates that the high-pressure valve displacement is maintained, but the hydraulic actuator pressure change is greater than that of the reference valve position holding segment. This suggests that the system needs to generate greater pressure compensation to maintain the same valve position, which may be due to internal leakage in the hydraulic actuator, micro-leakage in the hydraulic lines, leakage in the servo valve at the neutral position, or wear of the seals. For example, if the valve displacement change of the valve position holding segment does not exceed 0.12% of the full stroke, but the pressure change reaches 0.46 MPa, while the pressure change of the reference valve position holding segment is 0.15 MPa, then a "stable position leak" label will be generated.

[0036] The return friction label indicates that the high-pressure control valve has entered the reduced opening state, but the hydraulic actuator pressure has not transitioned to the depressurization state according to the health benchmark. This indicates that there is mechanical friction, poor valve stem return, insufficient spring return force, or obstruction of oil circuit depressurization during the return phase of the high-pressure control valve. For example, if the valve displacement decreases from 42.30% of the full stroke to 41.70% of the full stroke during the pressure return segment, but the hydraulic actuator pressure remains between 9.75MPa and 9.92MPa and does not fall below the lower pressure limit of 9.60MPa, then a return friction label will be generated.

[0037] Preferably, this embodiment compares the current hydraulic servo action of the high-pressure regulating valve with the baseline hysteresis action formed under the healthy state using corresponding segments, which solves the problem that it is difficult to distinguish different types of hydraulic hysteresis based solely on the current pressure value or the current valve position value. Through corresponding segment pairing groups and hydraulic hysteresis status tags, abnormalities in the start-up stage, follow-up stage, stabilization stage, and return stage can be located separately, so that the subsequent energy regulation amount is no longer generated based on a general alarm signal, but based on the specific hysteresis type, thereby improving the targeting of load regulation actions.

[0038] S3. Generate the energy adjustment amount based on the power response position of the hydraulic hysteresis state label after the valve displacement. Note that the following should be noted in this step: S3.1. Based on the termination sampling point number of the segment where the hydraulic hysteresis status label is located, establish a sequential association between the valve displacement status after the termination sampling point number and the unit's active power status according to the sampling point number; when the valve displacement status changes to the increased opening state, and the unit's active power status is in the maintained or decreased state, the power response position is determined as the power hysteresis position; when the valve displacement status is in the maintained state, and the unit's active power status alternates between the increased and decreased states between adjacent sampling points, the power response position is determined as the power fluctuation position; when the valve displacement status changes to the decreased opening state, and the unit's active power status is in the decreased state, the power response position is determined as the power drop position. S3.2 When the hydraulic hysteresis status label is a start-up hysteresis label or a follow-up jamming label, and the power response position is a power hysteresis position, the opening limit amount is formed according to the reverse constraint relationship of the valve opening increment. The reverse constraint relationships include: when the valve displacement state is in an increased opening state and the power response position is in a power lag position, the upper limit of the subsequent valve opening increment is set to be less than the current valve opening increment, forming an increased opening limit relationship; when the valve displacement state is in a maintained state and the unit's active power state is in a maintained or reduced state, the subsequent valve opening increment is kept at zero, forming a maintained limit relationship; when the valve displacement state changes from an increased opening state to a maintained state and the unit's active power state is in a maintained or reduced state, the upper limit of the subsequent valve opening increment is set to be less than the current valve opening increment, forming a decreasing limit relationship; wherein, the reverse constraint relationship consists of at least one of the increased opening limit relationship, the maintained limit relationship, and the decreasing limit relationship; S3.3 When the hydraulic hysteresis state label is a stable leakage label and the power response position is a power fluctuation position, the current valve displacement state is used as the holding object to form the valve position holding amount; S3.4 When the hydraulic hysteresis status label is the return friction label and the power response position is the power drop position, the load correction amount is formed according to the reduction of the unit's active power status. S3.5. Use the opening limit, valve position holding amount, or load correction amount as energy regulation amount.

[0039] It should be noted that the active power status of the unit in this embodiment includes an increased state, a decreased state, and a maintained state. The active power status of the unit is derived from the active power sampling value of the unit from the generator outlet power transmitter or the plant-level monitoring system. The active power sampling value of the unit is in MW and is arranged with the valve displacement status according to the same sampling point number or the sampling point number after time synchronization.

[0040] In this embodiment, the unit is a 600MW grid-connected steam turbine generator unit, and the power change dead zone is 0.60MW. The power change dead zone is determined by the allowable fluctuation of active power within 30 minutes of steady-state load operation of the unit. When the active power fluctuation is between 0.40MW and 0.60MW under the same steady-state load conditions, 0.60MW is taken as the power change dead zone.

[0041] Specifically, the "rising state" refers to an increase of more than 0.60MW in the active power sampled value of the unit at the subsequent sampling point compared to the previous sampling point; the "falling state" refers to a decrease of more than 0.60MW in the active power sampled value of the unit at the subsequent sampling point compared to the previous sampling point; and the "maintaining state" refers to a change in active power between adjacent sampling points that does not exceed 0.60MW. To reduce the impact of grid connection frequency disturbances, sampling points with a sudden drop in main steam pressure exceeding 0.30MPa or a grid connection frequency deviation exceeding 0.05Hz can be excluded from the power response position determination. After exclusion, adjacent sampling points continue to establish a sequential association between the valve displacement state and the active power state according to the original sampling point numbering order.

[0042] Furthermore, based on the termination sampling point number of the segment where the hydraulic hysteresis state label is located, the continuous sampling points after the termination sampling point number are selected as the power response determination interval. In this embodiment, the power response determination interval is the sampling points within 3 seconds after the termination sampling point number of the segment where the label is located. When the sampling point interval is 20ms, the power response determination interval contains 150 sampling points. The determination length of 3 seconds is chosen because the response of the high-pressure regulating valve displacement to the active power of the grid-connected steam turbine generator unit is usually delayed by the steam duct volume, steam flow and unit inertia. Too short an interval is difficult to cover the power response, while too long an interval is easy to mix in the main steam pressure regulation and grid frequency regulation disturbance.

[0043] It should be noted that the power lag position refers to a situation where, within the power response determination interval, the high-voltage control valve displacement state has switched to an increased opening state, but the unit's active power state remains in a maintained or decreased state. For example, if the hydraulic hysteresis state label is located at sampling point number 1020, and the control valve displacement state is in an increased opening state from sampling points number 1021 to 1060, while the unit's active power state is continuously in a maintained state, and a decreased state appears at sampling point number 1061, then the positions corresponding to sampling points number 1021 to 1061 are determined as the power lag positions.

[0044] The power fluctuation position refers to the situation where, within the power response determination interval, the high-voltage regulating valve displacement is in a stable state, but the active power of the unit repeatedly increases and decreases between adjacent sampling points. In this embodiment, if at least three alternations between increasing and decreasing states occur within 20 consecutive sampling points, and the regulating valve displacement remains stable, then the range of these consecutive sampling points is determined as the power fluctuation position.

[0045] The power drop position refers to the situation where, within the power response judgment range, the high-voltage control valve displacement state has shifted to a reduced-open state, and the unit's active power state is in a reduced state. For example, the hydraulic hysteresis state label is the return friction label, and the sampling point number of the segment where the label is located is 2050. Within the sampling point numbers 2051 to 2100, the control valve displacement state changes from a maintained state to a reduced-open state, and at the same time, the unit's active power decreases from 435.00MW to 431.80MW. Furthermore, the reduced state is met multiple times between adjacent sampling points. In this case, the sampling point range is determined as the power drop position.

[0046] In S3.2 to S3.5, the opening limit, valve position holding, and load correction are all determined by the hydraulic hysteresis status label and the power response position. When the hydraulic hysteresis status label is a start-up hysteresis label or a follow-up jamming label, and the power response position is a power lag position, it indicates that the high-pressure regulating valve opening action has not yet generated a corresponding increase in active power. If the regulating valve opening command is further expanded, it may cause a sudden increase in power after the hysteresis is released, thus forming an opening limit. The opening limit is based on the current regulating valve opening increment, limiting the subsequent regulating valve opening increment to a small range. For example, if the current regulating valve opening increment is 0.80% of the full stroke and the power lag lasts for 1.20s, then the opening limit can be taken as 0.40% of the full stroke, so that the subsequent regulating valve opening increment does not exceed 0.40% of the full stroke.

[0047] When the hydraulic hysteresis state label is a stable leakage label and the power response position is a power fluctuation position, it indicates that although the high-pressure control valve is in the valve position holding stage, the abnormal hydraulic motor pressure compensation has caused active power fluctuation. Therefore, the current valve displacement state is used as the constraint object to form the valve position holding amount. The valve position holding amount can be taken as the valve displacement sampling value at the beginning of the power fluctuation position. For example, if the high-pressure control valve displacement is 38.20% of the full stroke at the beginning of the power fluctuation position, then the valve position holding amount is 38.20% of the full stroke, and the allowable deviation is limited to 0.12% of the full stroke.

[0048] When the hydraulic hysteresis status label is the return friction label and the power response position is the power drop position, it indicates that the high-pressure regulating valve return process occurs synchronously with the decrease in the unit's active power. Furthermore, the hydraulic actuator's pressure relief is insufficient during the return process, which may lead to an excessively large load drop or unstable regulation. Therefore, a load correction amount is formed according to the decrease in the unit's active power. For example, if the unit's active power drops from 435.00MW to 431.80MW within the power drop position, a decrease of 3.20MW, then the load correction amount can be taken as a value within the range of 2.00MW to 3.20MW, opposite to the direction of decrease. In this embodiment, 2.40MW is used as the load correction amount to avoid a complete one-time offset that could cause reverse load fluctuations.

[0049] Preferably, by further mapping the hydraulic hysteresis type obtained in S2 to the active power response position of the unit, the problem of the lack of direct correspondence between the hydraulic hysteresis monitoring results and the grid-connected load adjustment action is solved; by distinguishing the power hysteresis position, power fluctuation position and power drop position, the starting hysteresis, follow-up jamming, stabilization leakage and return friction can be converted into opening limit amount, valve position holding amount or load correction amount respectively, so that the energy adjustment amount matches the actual action consequences of the high-pressure regulating valve, thereby reducing the risk of load change caused by hysteresis release.

[0050] S4. The energy regulation amount is sent to the turbine speed controller, which then adjusts the valve opening command or the unit load command. Note that the following points should be noted in this step: S4.1 When the energy regulation amount is the opening limit amount or the valve position holding amount, the opening limit amount or the valve position holding amount shall be assigned to the valve opening command regulation branch; when the energy regulation amount is the load correction amount, the load correction amount shall be assigned to the unit load command regulation branch. S4.2 In the regulating branch of the valve opening command, when the energy regulation amount is the opening limit amount, the opening limit amount is used as the upper limit constraint amount of the regulating valve opening command to form the regulating valve opening limit command; when the energy regulation amount is the valve position holding amount, the valve position holding amount is used as the holding constraint amount of the current regulating valve displacement state to form the regulating valve position holding command. S4.3 In the unit load command adjustment branch, the load correction amount is added to the current unit load command to form the unit load correction command; S4.4 When the turbine speed controller receives a valve opening limit command, it removes the portion of the current valve opening command that exceeds the opening limit, forming a valve opening command with the limit set. When the turbine speed controller receives a valve position holding command, it adjusts the current valve opening command to a holding command consistent with the valve position holding amount, forming a valve opening command with the valve position held. When the turbine speed controller receives a unit load correction command, it corrects the current unit load command according to the load correction amount, forming a corrected unit load command.

[0051] In a preferred embodiment, before the energy regulation amount enters the turbine speed controller, it is first branched and categorized by the regulation logic of the digital electro-hydraulic regulation system; the opening limit amount and the valve position holding amount are both categorized into the valve opening command regulation branch, and the load correction amount is categorized into the unit load command regulation branch; the valve opening command regulation branch directly acts on the increased opening portion of the high-pressure valve opening command or the current valve position constraint; the unit load command regulation branch acts on the unit load command and is transmitted to the valve opening command generation stage through the load control loop of the digital electro-hydraulic regulation system.

[0052] Specifically, the valve opening command at the current control moment and the valve opening command at the previous control moment are obtained first, and the additional opening portion between the two is compared. If the additional opening portion is greater than the opening limit, the portion exceeding the opening limit is deleted, and only the additional opening portion not exceeding the opening limit is retained. If the additional opening portion is not greater than the opening limit, the current valve opening command does not impose any additional opening restrictions. For example, if the high-voltage valve opening command at the previous control moment is 38.00% of the full stroke, and the high-voltage valve opening command at the current control moment is 38.90% of the full stroke, the additional opening portion is 0.90% of the full stroke. If the opening limit is 0.40% of the full stroke, then the valve opening command corresponding to the valve opening limit command is 38.40% of the full stroke.

[0053] Furthermore, using the valve displacement sampling value corresponding to the valve position holding amount as the target valve position, the current valve opening command is limited to the allowable deviation range near the target valve position. If the current valve opening command is higher than the upper boundary of the target valve position and the allowable deviation, the current valve opening command is lowered to the target valve position. If the current valve opening command is lower than the lower boundary of the target valve position and the allowable deviation, the current valve opening command is raised to the target valve position. If the current valve opening command is within the allowable deviation range, the current valve opening command continues. For example, if the valve position holding amount is 38.20% of the full stroke and the allowable deviation is 0.12% of the full stroke, the allowable range is 38.08% to 38.32% of the full stroke. If the current valve opening command is 38.70% of the full stroke, the valve opening command corresponding to the valve position holding command is adjusted to 38.20% of the full stroke.

[0054] Furthermore, if the active power of the unit corresponding to the power drop position decreases, the load correction amount is added to the current unit load command in the increasing direction; if the active power of the unit corresponding to the power response position increases abnormally, the load correction amount is added to the current unit load command in the decreasing direction. In this embodiment, the load correction amount in the increasing direction is used for the return friction tag and the power drop position. For example, if the current unit load command is 432.00MW and the load correction amount is 2.40MW, then the unit load command corresponding to the unit load correction command is 434.40MW. If the unit load limit is 450.00MW, then the unit load correction command does not exceed the load limit and can proceed to the subsequent control stage.

[0055] It should be noted that after receiving the valve opening limit command, the turbine speed controller decomposes the current valve opening command into the valve opening command of the previous control moment and the additional opening portion of the current control moment; it compares the additional opening portion of the current control moment with the opening limit amount; it retains only the additional opening portion that is not greater than the opening limit amount; it deletes the additional opening portion that exceeds the opening limit amount; and then it combines the retained additional opening portion with the valve opening command of the previous control moment to form the limited valve opening command. For example, if the valve opening command of the previous control moment is 40.00% of the full stroke, the current valve opening command is 41.20% of the full stroke, and the opening limit amount is 0.50% of the full stroke, then the 0.70% of the full stroke additional opening portion that exceeds 0.50% of the full stroke is deleted, and the limited valve opening command is 40.50% of the full stroke.

[0056] After receiving the valve position holding command, the turbine speed controller compares the current valve opening command with the valve position holding amount. If the current valve opening command deviates from the valve position holding amount by more than the allowable deviation, the current valve opening command is adjusted to the valve position holding amount. If the deviation between the current valve opening command and the valve position holding amount does not exceed the allowable deviation, the current valve opening command is continued. At the same time, the opening rate and closing rate of the valve opening command are limited within the safety valve position change range of the digital electro-hydraulic control system. For example, if the valve position holding amount is 35.60% of the full stroke, the allowable deviation is 0.12% of the full stroke, and the current valve opening command is 35.95% of the full stroke, then the current valve opening command exceeds the upper limit of the allowable range of 35.72% of the full stroke, and the turbine speed controller adjusts the valve opening command to 35.60% of the full stroke.

[0057] It should also be noted that after receiving the unit load correction command, the turbine speed controller superimposes the current unit load command with the load correction amount in the correct direction. The superimposed unit load command is then compared with the unit load upper limit, unit load lower limit, main steam pressure constraint, and the safe range of the control valve opening. When the superimposed unit load command falls within the above ranges, a corrected unit load command is formed. When the superimposed unit load command exceeds the unit load upper limit, the unit load upper limit is used as the corrected unit load command. When the superimposed unit load command is lower than the unit load lower limit, the corrected unit load command is formed. When the unit load is at the lower limit, the lower limit of the unit load is used as the corrected unit load command. For example, if the current unit load command is 432.00MW, the load correction is 2.40MW, the upper limit of the unit load is 450.00MW, and the lower limit of the unit load is 300.00MW, then the corrected unit load command is 434.40MW. If the current unit load command is 449.00MW and the load correction is 2.40MW, then the sum exceeds 450.00MW, and the corrected unit load command is 450.00MW.

[0058] As a preferred example, a 600MW grid-connected steam turbine generator unit operates at a load of 430.00MW. The high-pressure regulating valve opening command increases from 38.00% of its full stroke to 38.90% of its full stroke. The digital electro-hydraulic control system obtains a hydraulic actuator pressure sampling value that increases from 9.82MPa to 10.54MPa, while the high-pressure regulating valve displacement only increases from 38.05% of its full stroke to 38.12% of its full stroke. The pressure change amplitude of the pressure starting segment is greater than that of the reference pressure starting segment, and the displacement change amplitude of the pressure starting segment is less than that of the reference pressure starting segment, thus generating a starting hysteresis label; subsequently, within 3 seconds... Within the power response judgment range, the high-pressure regulating valve displacement state transitions to an increased opening state, but the unit's active power remains between 429.80MW and 430.20MW, failing to form an effective increase state. The power response position is the power lag position. Based on the start-up hysteresis tag and the power lag position, a 0.40% full-stroke opening limit is generated. The turbine speed controller limits the current regulating valve opening command of 38.90% full stroke to 38.40% full stroke. In this way, further increased opening is restricted before the high-pressure regulating valve hysteresis is released, reducing the risk of a sudden surge in the unit's active power after the hysteresis is released.

[0059] Preferably, by converting the energy regulation amount generated by S3 into a valve opening limit command, valve position holding command, or unit load correction command that can be executed by the turbine speed controller, this embodiment solves the problem that the hydraulic hysteresis monitoring results remain at the state identification level and are difficult to participate in grid-connected load regulation. By limiting the opening portion of the valve opening command, constraining the current valve position, and correcting the direction of the unit load command, the hydraulic servo hysteresis monitoring results of the high-pressure valve can directly participate in the unit energy regulation process, thereby reducing the impact of high-pressure valve jamming, leakage, or return friction on the stability of grid-connected load.

[0060] 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. A monitoring and energy regulation method for a steam turbine speed control system based on hydraulic servo state quantity fusion, characterized in that, include: Based on the sequential relationship between the change of hydraulic actuator pressure state and valve displacement state in the turbine speed control system, the system is divided into segments, and a hysteresis loop segment index is generated. The hysteresis loop fragment index is compared with the baseline hysteresis loop index formed based on the healthy operating conditions to generate hydraulic hysteresis state labels. Based on the power response position of the hydraulic hysteresis state label after the valve displacement, an energy adjustment amount is generated; The energy regulation amount is sent to the turbine speed controller, which then adjusts the valve opening command or the unit load command.

2. The monitoring and energy regulation method for a steam turbine speed control system based on hydraulic servo state quantity fusion according to claim 1, characterized in that, Generating the hysteresis loop shard index includes: The hydraulic actuator pressure state is divided into pressure increase state, pressure decrease state, pressure bearing state and pressure relief state, and the valve displacement state is divided into open state, closed state and holding state. The hydraulic actuator pressure state and the valve displacement state are arranged in a one-to-one correspondence according to the sampling point number to form a hydraulic actuator pressure-valve displacement state sequence. In the hydraulic actuator pressure-valve displacement state sequence, the section where the hydraulic actuator pressure state changes from a pressurized state or a depressurized state to a pressurized state while the valve displacement state is in a holding state is divided into a pressure start segment; the section where the hydraulic actuator pressure state is in a pressurized state while the valve displacement state changes from a holding state to an open state is divided into a displacement follow-up segment; the section where the valve displacement state is in a holding state while the hydraulic actuator pressure state switches between a pressurized state and a pressurized state is divided into a valve position holding segment; and the section where the valve displacement state changes from a holding state to a closed state while the hydraulic actuator pressure state changes from a pressurized state to a depressurized state is divided into a pressure return segment. The hysteresis loop segment index is generated according to the arrangement order of the pressure start segment, the displacement follow-up segment, the valve position holding segment, and the pressure return segment.

3. The monitoring and energy regulation method for a steam turbine speed control system based on hydraulic servo state quantity fusion according to claim 2, characterized in that, The pressure states of the hydraulic actuator are divided into pressure boosting, pressure depressurization, pressure bearing, and pressure relief states, including: Obtain the hydraulic motor pressure sampling values ​​of the same valve at two adjacent sampling points, and calculate the pressure difference formed by the hydraulic motor pressure sampling value of the later sampling point relative to the hydraulic motor pressure sampling value of the previous sampling point; When the pressure difference is positive and the pressure difference is greater than the pressure change dead zone, the oil motor pressure state of the next sampling point is classified as a pressure increase state. The pressure change dead zone is determined by the allowable fluctuation of the oil motor pressure in the steady-state load test of the turbine speed control system. When the pressure difference is negative, the absolute value of the pressure difference is greater than the pressure change dead zone, and the hydraulic motor pressure sampling value of the next sampling point is between the lower pressure limit and the upper pressure limit, the hydraulic motor pressure state of the next sampling point is classified as a pressure reduction state. When the hydraulic motor pressure sampling value at the next sampling point is between the lower pressure limit and the upper pressure limit, and the absolute value of the pressure difference is not greater than the pressure change dead zone, the hydraulic motor pressure state at the next sampling point is classified as a pressure-bearing state. When the hydraulic motor pressure sample value at the next sampling point is less than the lower pressure limit and the pressure difference is negative, the hydraulic motor pressure state at the next sampling point is classified as a depressurization state. Wherein, the lower pressure limit is the minimum hydraulic motor pressure required to keep the valve displacement unchanged, and the upper pressure limit is the maximum hydraulic motor pressure required to keep the valve displacement unchanged without causing the valve to continue to open further.

4. The monitoring and energy regulation method for a steam turbine speed control system based on hydraulic servo state quantity fusion according to claim 2, characterized in that, The valve displacement state is divided into an increased opening state, a decreased opening state, and a holding state, including: Obtain the valve displacement sampling values ​​of the same valve at two adjacent sampling points, and calculate the displacement difference formed by the valve displacement sampling value of the later sampling point relative to the valve displacement sampling value of the previous sampling point; When the displacement difference is positive and the displacement difference is greater than the displacement change dead zone, the valve displacement state of the next sampling point is divided into an increased opening state. The displacement change dead zone is determined by the larger of the displacement resolution of the valve position feedback device and the allowable valve position jitter during steady-state operation of the turbine speed control system. When the displacement difference is negative and the absolute value of the displacement difference is greater than the displacement change dead zone, the valve displacement state of the next sampling point is divided into a reduced opening state. When the absolute value of the displacement difference is not greater than the displacement change dead zone, the valve displacement state of the next sampling point is classified as a holding state.

5. The monitoring and energy regulation method for a steam turbine speed control system based on hydraulic servo state quantity fusion according to claim 1, characterized in that, The process of comparing fragments with the same name includes: Based on the pressure start segment, displacement follower segment, valve position holding segment, and pressure return segment in the hysteresis loop segment index, they are paired one-to-one with the reference pressure start segment, reference displacement follower segment, reference valve position holding segment, and reference pressure return segment in the reference hysteresis loop index to form a segment pairing group with the same name. In the same-name segment pairing group, the pressure initiation segment, displacement follower segment, valve position holding segment, and pressure return segment in the hysteresis loop segment index are compared with the reference pressure initiation segment, reference displacement follower segment, reference valve position holding segment, and reference pressure return segment in the reference hysteresis loop index, respectively, in terms of pressure change direction, displacement change direction, pressure change amplitude, and displacement change amplitude; wherein: When the pressure change amplitude of the pressure start-up segment is greater than the pressure change amplitude of the reference pressure start-up segment, and the displacement change amplitude of the pressure start-up segment is less than the displacement change amplitude of the reference pressure start-up segment, a start-up hysteresis tag is generated. When the pressure change direction of the displacement follower segment is opposite to the displacement change direction of the displacement follower segment, or when the displacement change amplitude of the displacement follower segment is less than the displacement change amplitude of the reference displacement follower segment, a follower tag is generated. When the valve position holding segment is in a holding state and the pressure change of the valve position holding segment is greater than the pressure change of the reference valve position holding segment, a stable leakage tag is generated. When the valve displacement state of the pressure return segment is in the reduced opening state, and the hydraulic pressure state of the pressure return segment has not switched to the depressurization state, a return friction tag is generated.

6. The monitoring and energy regulation method for a steam turbine speed control system based on hydraulic servo state quantity fusion according to claim 5, characterized in that, The hydraulic hysteresis status label includes the starting hysteresis label, the follow-up jamming label, the stabilization leakage label, and the return friction label.

7. The monitoring and energy regulation method for a steam turbine speed control system based on hydraulic servo state quantity fusion according to claim 1, characterized in that, Generating the energy regulation amount includes: Based on the termination sampling point number of the segment where the hydraulic hysteresis state label is located, the valve displacement state after the termination sampling point number is sequentially associated with the unit's active power state according to the sampling point number; when the valve displacement state transitions to an increased opening state, and the unit's active power state is in a maintained or decreased state, the power response position is determined as the power hysteresis position; when the valve displacement state is in a maintained state, and the unit's active power state alternates between increased and decreased states between adjacent sampling points, the power response position is determined as the power fluctuation position; when the valve displacement state transitions to a decreased opening state, and the unit's active power state is in a decreased state, the power response position is determined as the power drop position. When the hydraulic hysteresis status label is a start-up hysteresis label or a follow-up jamming label, and the power response position is a power hysteresis position, the opening limit is formed according to the reverse constraint relationship of the valve opening increment. When the hydraulic hysteresis state label is a stable leakage label and the power response position is a power fluctuation position, the current valve displacement state is used as the holding object to form the valve position holding amount; When the hydraulic hysteresis state label is the return friction label and the power response position is the power drop position, the load correction amount is formed according to the reduction of the active power state of the unit. The opening limit, the valve position holding amount, or the load correction amount are used as the energy regulation amount.

8. The monitoring and energy regulation method for a steam turbine speed control system based on hydraulic servo state quantity fusion according to claim 7, characterized in that, The reverse constraint relationship includes: When the valve displacement state is in the increased opening state and the power response position is the power lag position, the upper limit of the subsequent valve opening increment is set to be less than the current valve opening increment, thus forming an increased opening limit relationship. When the valve displacement state is in a holding state and the unit active power state is in a holding or decreasing state, the subsequent valve opening increment will be kept at zero, forming a holding limit relationship. When the valve displacement state changes from the increased opening state to the maintained state, and the unit active power state is maintained or reduced, the upper limit of the subsequent valve opening increment is set to be less than the current valve opening increment upper limit, forming a decreasing limit relationship. The reverse constraint relationship is composed of at least one of the expansion limiting relationship, the maintenance limiting relationship, and the decreasing limiting relationship.

9. The monitoring and energy regulation method for a steam turbine speed control system based on hydraulic servo state quantity fusion according to claim 1, characterized in that, The turbine speed control controller's instructions for adjusting the valve opening or the unit load include: When the energy regulation amount is an opening limit amount or a valve position holding amount, the opening limit amount or the valve position holding amount is assigned to the valve opening command regulation branch; when the energy regulation amount is a load correction amount, the load correction amount is assigned to the unit load command regulation branch. In the valve opening command adjustment branch, when the energy adjustment amount is the opening limit amount, the opening limit amount is used as the upper limit constraint amount of the valve opening command to form the valve opening limit command; when the energy adjustment amount is the valve position holding amount, the valve position holding amount is used as the holding constraint amount of the current valve displacement state to form the valve position holding command. In the unit load command adjustment branch, the load correction amount is superimposed on the current unit load command to form a unit load correction command.

10. The monitoring and energy regulation method for a steam turbine speed control system based on hydraulic servo state quantity fusion according to claim 9, characterized in that, Also includes: When the turbine speed controller receives the valve opening limit command, it removes the portion of the valve opening that exceeds the limit in the current valve opening command, and forms a valve opening command with the limit. When the turbine speed controller receives the valve position holding command, it adjusts the current valve opening command to a holding command consistent with the valve position holding amount, thus forming a valve opening command after valve position holding. When the turbine speed controller receives the unit load correction command, it corrects the current unit load command according to the load correction amount to form the corrected unit load command.

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