A fault monitoring and control correction method for a steam turbine governing system

Abstract

The application discloses a kind of for steam turbine governing system's fault monitoring and control correction method, comprising: by according to the sequential relationship and the consistent relationship between the opening degree instruction of governing valve, the actual opening degree of governing valve, oil motor pressure state and servo valve driving state, the action process of governing valve is divided, and continuous governing valve action is divided into the action piece with different physical characteristics of receiving;Through the correlation determination of governing valve opening degree deviation, oil motor pressure state and servo valve driving state, the abnormal performance of actuator side is identified;Then through the consistency determination of speed acquisition channel state, valve position feedback channel state and servo driving channel state, the abnormal performance of channel side is identified;Finally, the governing valve state label and link state label cross check, avoid feedback channel abnormal misjudgment as actuator abnormality, and generate governing valve control correction amount accordingly;Steam turbine governing system fault source distinguishing accuracy and governing valve control correction stability are improved.

Description

Technical Field

[0001] This invention relates to the technical field of turbine speed control, and in particular to a fault monitoring and control correction method for turbine speed control systems. Background Technology

[0002] As large thermal power units, combined heat and power units, and industrial drive steam turbines develop towards higher parameters, larger capacity, and faster load response, steam turbine speed control systems have gradually evolved from early mechanical hydraulic speed control to control systems centered on digital electro-hydraulic regulation systems. These systems typically form a control network through speed acquisition channels, valve position feedback channels, servo drive channels, servo valves, hydraulic actuators, and control valves. They regulate steam flow by adjusting the valve opening, thereby maintaining the stability of unit speed, load, and operating condition transitions. Because the valve operation is simultaneously affected by the valve opening command, the actual valve opening, the hydraulic actuator pressure status, the servo valve drive status, and the speed feedback status, fault manifestations are often… There are multiple sources of coupling characteristics. For example, valve opening deviation may originate from abnormal hydraulic actuator pressure, servo valve drive deviation, or valve actuator lag, or from abnormal valve position feedback channel, speed acquisition channel, or servo drive channel. Existing turbine speed control system fault monitoring technologies mostly rely on model output error, oil pressure threshold, valve position deviation, or single control loop status as the basis for judgment. While these technologies can provide alarms or diagnoses for some faults, they lack segmented representation of the valve action stages during the continuous process of valve operation from start-up, following, pressure bearing, to return. They also lack a control correction mechanism that cross-checks the actuator-side status with the acquisition, feedback, and drive channel status. Therefore, when there is a deviation between the actual valve opening and the valve opening command, existing technologies are prone to misjudging feedback channel abnormalities as actuator abnormalities, or hydraulic actuator pressure abnormalities as deviations in conventional speed control parameters. This leads to unnecessary control corrections, causing valve fluctuations, load disturbances, or fault location errors.

[0003] For example, CN103089342A discloses a method for correcting the model parameters of a steam turbine and its speed control system. This method establishes a model of the steam turbine and its speed control system of a power grid generator set, and determines whether the model output data exceeds the error threshold under disturbance conditions. Then, it performs at least one correction operation among dynamic inequality correction, regenerative system correction, and nonlinear characteristic correction to obtain a corrected model of the steam turbine and its speed control system. The method focuses on model parameter correction and model output matching, and is suitable for improving the consistency between the steam turbine and its speed control system model and the actual operating data. However, it does not establish starting segment, following segment, pressure-bearing segment, and return segment based on the valve action process, nor does it form a valve action segment index based on the sequential relationship and consistent change relationship between the valve opening command, the actual valve opening, the hydraulic motor pressure state, and the servo valve drive state. Therefore, in actual speed control, the method provided by CN103089342A is difficult to distinguish whether the valve opening deviation is caused by an abnormality on the actuator side or by an abnormality in the speed acquisition channel, valve position feedback channel or servo drive channel. It has problems such as insufficient differentiation of fault sources and insufficient control correction basis to match the valve action stage.

[0004] For example, CN110593964A discloses a method and system for diagnosing faults in the opening process of a feedwater pump turbine's fast-closing valve. This method sends a start command to the fast-closing oil control valve and the starting oil control valve, monitors the output oil pressure of the fast-closing oil control valve and the starting oil control valve, and determines whether the output oil pressure reaches or remains within the corresponding oil pressure range within a specific time period. This allows for the differentiation of fault types such as faults in the fast-closing oil control valve, faults in the starting oil control valve, and abnormalities in the mechanical valve body or oil circuit despite normal operation of the electrical control signal circuit. This method can diagnose faults in the oil pressure changes during the opening process of the feedwater pump turbine's fast-closing valve. However, its judgment is mainly based on the fast-closing oil control valve, the starting oil control valve, and their output oil pressure. It does not continuously correlate the valve opening command, the actual valve opening, the oil motor pressure status, and the servo valve drive status according to the valve action stage, nor does it make a consistency judgment between the valve execution status and the speed acquisition channel status, the valve position feedback channel status, and the servo drive channel status. Therefore, the method provided by CN110593964A is difficult to suppress erroneous corrections caused by feedback channel anomalies in the closed-loop control scenario of the valve in a steam turbine speed control system, and it is also difficult to generate differentiated valve control correction amounts based on different valve actions.

[0005] In summary, given that existing fault monitoring technologies for steam turbine speed control systems suffer from insufficient expression of the valve action phase, unclear distinction between actuator abnormalities and control channel abnormalities, and difficulty in directly supporting valve control correction with fault diagnosis results, this invention proposes a fault monitoring and control correction method for steam turbine speed control systems. This method aims to address the problem of erroneous corrections caused by the inability to distinguish between actuator-side faults and acquisition, feedback, and drive channel-side faults when the steam turbine speed control system is in a valve deviation state. 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: a method for fault monitoring and control correction of a steam turbine speed regulation system, comprising: Based on the sequential and consistent relationship between the valve opening command, the actual valve opening, the hydraulic motor pressure state, and the servo valve drive state in the turbine speed control system, the valve action process is divided and a valve action segment index is generated. Based on the valve action segment index, the valve opening deviation, hydraulic motor pressure status and servo valve drive status in the turbine speed control system are correlated and determined to generate valve status labels. Based on the valve action segmentation index, the consistency of the speed acquisition channel status, valve position feedback channel status and servo drive channel status in the turbine speed control system is determined, and a link status label is generated. The valve status label and the link status label are cross-checked to generate a valve control correction value, which is then sent to the turbine speed controller.

[0009] The beneficial effects of this invention are as follows: Based on the sequential and consistent relationship between the valve opening command, the actual valve opening, the hydraulic actuator pressure state, and the servo valve drive state, this invention divides the valve action process, enabling the continuous valve action to be divided into action segments with different physical connection characteristics. Furthermore, by determining the correlation between valve opening deviation, hydraulic actuator pressure state, and servo valve drive state, abnormal behavior on the actuator side is identified. Then, by determining the consistency of the speed acquisition channel state, valve position feedback channel state, and servo drive channel state, abnormal behavior on the channel side is identified. Finally, the valve status label and the link status label are cross-checked to avoid misjudging feedback channel abnormalities as actuator abnormalities, and valve control correction values ​​are generated accordingly. This improves the accuracy of fault source differentiation and the stability of valve control correction in the turbine speed control system. 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 fault monitoring and control correction method for a steam turbine speed control system according to the present invention. Figure 2 This is a schematic diagram illustrating the process of dividing the starting segment, following segment, pressure-bearing segment, and return segment 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] This embodiment is applied to the scenario of monitoring and controlling the fault correction of valve opening deviation during the load regulation process of the high-pressure regulating valve of a thermal power unit. The turbine speed regulation system of the thermal power unit includes a turbine speed controller, a high-pressure regulating valve, a hydraulic actuator, a servo valve, a valve position sensor, a speed acquisition module, and a servo drive module. During the load regulation process, the turbine speed controller outputs a regulating valve opening command. The servo drive module outputs a drive current to the servo valve according to the regulating valve opening command. The servo valve adjusts the oil pressure state on the oil inlet and return sides of the hydraulic actuator. The hydraulic actuator drives the high-pressure regulating valve to produce a large opening or small closing action. The valve position sensor collects the actual opening of the regulating valve, and the speed acquisition module collects the turbine speed state.

[0015] In this embodiment, the valve opening command is the target opening percentage of the high-pressure valve output by the turbine speed controller, with a value range of 0% to 100%; the actual valve opening is the actual opening percentage of the high-pressure valve output by the valve position sensor, with a value range of 0% to 100%; the hydraulic actuator pressure status is represented by the hydraulic actuator inlet side pressure, return side pressure, and the pressure difference formed between the two; the servo valve drive status is represented by the drive current output by the servo drive module to the servo valve coil; the sampling interval is 10ms, the single judgment window is 200ms, corresponding to 20 sampling positions.

[0016] According to an embodiment of the present invention, in combination Figure 1 , Figure 2 The flowchart shown illustrates a fault monitoring and control correction method for a steam turbine speed control system, which specifically includes the following steps: S1. Based on the sequential and consistent relationships between the valve opening command, actual valve opening, hydraulic actuator pressure state, and servo valve drive state in the turbine speed control system, the valve action process is divided, and a valve action segment index is generated. Note that the following should be noted in this step: S1.1 Synchronously arrange the valve opening command, actual valve opening, hydraulic motor pressure status, and servo valve drive status in the turbine speed control system at the same sampling time to form a valve action status sequence.

[0017] Specifically, the valve opening command is obtained from the high-pressure valve control output of the turbine speed controller; the actual valve opening is obtained from the high-pressure valve stem position sensor; the hydraulic actuator pressure status is obtained from the hydraulic actuator inlet-side pressure transmitter and the hydraulic actuator return-side pressure transmitter; and the servo valve drive status is obtained from the current detection unit at the output of the servo drive module. Before entering the fault monitoring unit of the turbine speed controller, all four types of signals are accompanied by a sampling time. When the difference in sampling time between the four types of signals is no greater than 2ms, the four types of signals are merged into the same sampling position. When the difference in sampling time between any signal is greater than 2ms, the signal is merged into the sampling position with the smaller time distance according to the numerical change order of two adjacent sampling positions. This forms a sequence of valve action states arranged in ascending order of sampling positions.

[0018] Furthermore, each sampling position in the valve action state sequence includes the valve opening command, the actual valve opening, the hydraulic actuator pressure state, and the servo valve drive state; among which, the valve opening command state includes the increase state, the decrease state, and the hold state; the actual valve opening state includes the open state, the close state, and the stationary state; the hydraulic actuator pressure state includes the pressure increase state, the pressure decrease state, and the pressure stabilization state; and the servo valve drive state includes the increase drive state, the decrease drive state, and the drive stabilization state.

[0019] Specifically, when the valve opening command increment between two adjacent sampling positions is not less than 0.2%, the valve opening command status is in the increasing state; when the valve opening command decrement between two adjacent sampling positions is not less than 0.2%, the valve opening command status is in the decreasing state; when the valve opening command change between two adjacent sampling positions is less than 0.2%, the valve opening command status is in the holding state; the actual valve opening status is divided into large opening, small closing, and stationary states according to a change boundary of 0.15%; the hydraulic actuator pressure status is divided into pressure increase, pressure decrease, and pressure stabilization states according to a change boundary of 0.05MPa; and the servo valve drive status is divided into increased drive, decreased drive, and stable drive states according to a change boundary of 0.3mA.

[0020] S1.2. Generate the sequence of valve actions based on the changes in the valve opening command, the servo valve drive state, the hydraulic actuator pressure state, and the actual valve opening in the valve action state sequence.

[0021] Specifically, the sequence of valve actions includes the order of the changes in the valve opening command, the servo valve drive state, the hydraulic actuator pressure state, and the actual valve opening in the valve action state sequence; among which: In the valve action state sequence, the sampling position where the valve opening command first changes from the holding state to the increasing state or the decreasing state is determined as the change position of the valve opening command; the sampling position where the servo valve drive state first changes from the drive smooth state to the increase drive state or the decrease drive state is determined as the change position of the servo valve drive state; the sampling position where the hydraulic actuator pressure state first changes from the pressure smooth state to the pressure increase state or the pressure decrease state is determined as the change position of the hydraulic actuator pressure state; and the sampling position where the actual valve opening first changes from the stationary state to the open state or the closed state is determined as the change position of the actual valve opening. When the positions of the valve opening command change, the servo valve drive state change, the hydraulic motor pressure state change, and the actual valve opening change are arranged sequentially, and the sampling position interval between adjacent change positions is no more than 5 sampling positions, a command drive pressure opening succession relationship is generated. This relationship indicates that the load adjustment command first enters the speed controller, the servo valve then generates a drive response, the hydraulic motor pressure changes again, and the actual valve opening finally undergoes mechanical action, which conforms to the normal action sequence of the high-pressure valve hydraulic servo execution process. When the change in the servo valve drive state occurs earlier than the change in the valve opening command, an abnormal sequential relationship is generated. This relationship indicates that the servo drive change is not caused by the current valve opening command, and there may be servo drive channel disturbance or residual influence from historical control quantities. Similarly, when the change in the actual valve opening occurs earlier than the change in the hydraulic actuator pressure state, an abnormal sequential relationship is generated. This relationship indicates that the hydraulic connection between the valve position feedback change and the hydraulic actuator pressure change is inconsistent, and there may be abnormal valve position feedback channel or false opening changes caused by valve mechanical clearance. When the change in pressure state of the hydraulic actuator has occurred, and no change in the actual opening of the control valve has occurred in the subsequent 6 consecutive sampling positions, a pressure-no-opening continuity relationship is generated. This relationship indicates that the hydraulic actuator has generated a pressure change, but the high-pressure control valve has not generated a corresponding large opening or small closing action, which may be due to hydraulic actuator jamming, control valve linkage obstruction, or abnormal mechanical resistance of the actuator.

[0022] For example, during a load adjustment process where the high-pressure regulating valve is adjusted from 42.0% to 46.0%, the valve opening command changes from a holding state to an increasing state at the 3rd sampling position, the servo valve drive state changes from a stable drive state to an increasing drive state at the 4th sampling position, the hydraulic actuator pressure state changes from a stable pressure state to a boosting pressure state at the 6th sampling position, and the actual valve opening changes from a stationary state to a fully open state at the 8th sampling position. In this case, a command-driven pressure opening continuity relationship is generated. If, in another judgment window, the hydraulic actuator pressure state changes to a boosting pressure state at the 5th sampling position, but the actual valve opening remains stationary until the 12th sampling position, then a pressure opening continuity relationship is generated.

[0023] S1.3. Generate a consistent relationship between the valve action changes based on the direction and magnitude of changes in the valve opening command, actual valve opening, hydraulic motor pressure state, and servo valve drive state in the valve action state sequence.

[0024] Specifically, the consistency of changes in valve movement includes consistency in the direction of change and consistency in the magnitude of change; among which: First, determine the direction of change of the valve opening command, the actual valve opening, the hydraulic motor pressure status, and the servo valve drive status according to the numerical changes between two adjacent sampling positions; then determine the magnitude of change of the valve opening command, the actual valve opening, the hydraulic motor pressure status, and the servo valve drive status according to the magnitude of the numerical changes between two adjacent sampling positions. The direction of change is determined by the sequence of four types of signals: a positive continuity relationship is generated when the valve opening command is increasing, the servo valve drive is increasing, the hydraulic actuator pressure is increasing, and the actual valve opening is wide open; a positive continuity relationship is also generated when the valve opening command is decreasing, the servo valve drive is decreasing, the hydraulic actuator pressure is decreasing, and the actual valve opening is closing; a direction deviation relationship is generated when the valve opening command and the servo valve drive are in the same direction, but the hydraulic actuator pressure does not increase or decrease with the servo valve drive; a direction deviation relationship is also generated when the hydraulic actuator pressure has increased or decreased, but the actual valve opening has not widened or closed. The continuity of amplitude variation is determined by the continuity of numerical changes between adjacent sampling positions: when the valve opening command changes, the servo valve drive state changes in the same direction within 5 adjacent sampling positions, the hydraulic actuator pressure state changes in the same direction within 5 subsequent sampling positions, and the actual valve opening changes in the same direction within 8 subsequent sampling positions. If the amplitude of the actual valve opening change does not show a reverse change or a stagnant change for 3 consecutive sampling positions, a continuity of amplitude variation is generated. If any adjacent sampling position shows a change in the opposite direction to the command, or if the amplitude of the actual valve opening change is less than 0.05% within 3 consecutive sampling positions, a discontinuous amplitude variation is generated.

[0025] For example, during the high-pressure regulating valve opening adjustment process, if the valve opening command increases from 42.0% to 46.0% within 200ms, the servo valve drive state increases from 12.0mA to 15.5mA, the hydraulic actuator inlet pressure increases from 8.6MPa to 9.1MPa, and the actual valve opening increases from 42.1% to 45.7%, and the actual valve opening does not decrease at any sampling position, then a positive continuity relationship and an amplitude continuity relationship are generated. If the hydraulic actuator inlet pressure has already increased from 8.6MPa to 9.1MPa, and the actual valve opening is 42.1%, 42.1%, and 42.1% in three consecutive sampling positions, then a directional deviation relationship and an amplitude discontinuity relationship are generated.

[0026] S1.4. Based on the sequential relationship of the regulating valve actions and the consistency of the regulating valve action changes, the regulating valve action state sequence is divided into starting segment, following segment, pressure-bearing segment, and return segment, and a regulating valve action segment index is generated according to the segment sequence.

[0027] Specifically, the valve action state sequence is divided into starting segment, following segment, pressure-bearing segment, and return segment, including: When the sequence of valve actions is a command-driven pressure opening succession relationship, and the valve opening command changes from a holding state to an increasing state or a decreasing state, the servo valve drive state changes to an increasing drive state or a decreasing drive state according to the valve opening command, but the actual valve opening has not yet formed a continuous opening state or a continuous closing state, the valve action state sequence is divided into a starting segment. When the relationship between the changes in the valve action is a positive succession relationship, and the direction of change of the actual valve opening is consistent with the direction of change of the valve opening command, and the range of change of the actual valve opening is continuously followed by the range of change of the valve opening command, the valve action state sequence is divided into a following segment. When the pressure state of the hydraulic actuator has changed to the pressure increase state or the pressure decrease state, the servo valve drive state remains in the increase drive state or the decrease drive state, and the change range of the actual opening of the regulating valve does not change continuously with the pressure state of the hydraulic actuator, the sequence of regulating valve action states is divided into pressure-bearing segments. When the gate opening command changes from an increasing or decreasing state to a holding state, or when the direction of the gate opening command changes in the opposite direction and the actual gate opening returns to the opening position indicated by the gate opening command, the sequence of gate action states is divided into return segments.

[0028] Furthermore, the starting segment uses the change position of the valve opening command as the starting point and the sampling position preceding the sampling position where the actual valve opening first forms a continuous opening or closing state as the ending point; the following segment uses the sampling position where the actual valve opening first forms a continuous opening or closing state as the starting point and the sampling position preceding the sampling position where the change amplitude of the actual valve opening begins to be less than 0.05% as the ending point; the pressure segment uses the hydraulic actuator pressure state after it has switched to a pressurization state or a depressurization state. Furthermore, the sampling position where the actual opening of the damper does not form a continuous change is the starting point of the segmentation, and the sampling position before the sampling position where the actual opening of the damper resumes a continuous change is the ending point of the segmentation; the return segmentation starts at the sampling position where the damper opening command changes from an increasing or decreasing state to a holding state, or where the damper opening command changes in the opposite direction, and ends at the sampling position where the actual opening of the damper enters the neighborhood of the opening position indicated by the damper opening command; the neighborhood of the opening position is a range of 0.3% on both sides of the value of the damper opening command.

[0029] The valve action segment index includes segment name, segment start sampling time, segment end sampling time, valve action sequence, valve action consistency, and segment order. The segment order is arranged as starting segment, following segment, pressure-bearing segment, and return segment. When no pressure-bearing segment appears during a load regulation process, the valve action segment index is arranged as starting segment, following segment, and return segment. When there is no pressure opening connection, the pressure-bearing segment is inserted after the starting segment or among the following segments, and arranged in the order of actual sampling positions.

[0030] It should be noted that by incorporating the changes in commands, servo drive, hydraulic motor pressure, and actual valve opening during the high-pressure valve load adjustment process into the same time series, and dividing the valve action into segments according to the physical sequence of the hydraulic servo execution process, the problems of unclear action process boundaries and mixed fault judgment objects in valve opening deviation fault monitoring are solved. As a result, the status judgment can be performed separately for the start-up, following, pressure bearing, and return processes in subsequent steps, reducing misjudgments caused by simply judging faults based on valve opening deviation.

[0031] S2. Based on the valve action segment index, correlate and determine the valve opening deviation, hydraulic actuator pressure status, and servo valve drive status in the turbine speed control system, and generate valve status labels. Note that the following points should be noted in this step: S2.1. According to the valve action segment index, extract the valve opening deviation, hydraulic motor pressure status and servo valve drive status from the starting segment, following segment, pressure bearing segment and return segment respectively to form a segment status combination.

[0032] Specifically, the damper opening deviation is the difference between the damper opening command and the actual damper opening at the same sampling position; when the damper opening command is greater than the actual damper opening, the damper opening deviation is an opening deviation; when the damper opening command is less than the actual damper opening, the damper opening deviation is a closing deviation; when the absolute value of the difference between the damper opening command and the actual damper opening is less than 0.3%, the damper opening deviation is a minor deviation.

[0033] Furthermore, the method for extracting the valve opening deviation, hydraulic motor pressure status, and servo valve drive status from the starting segment, following segment, pressure-bearing segment, and return segment is as follows: Based on the segment start sampling time and segment end sampling time in the valve action segment index, extract the valve opening deviation, hydraulic motor pressure status, and servo valve drive status corresponding to each sampling position within the same segment range from the valve action status sequence; arrange them according to the order of sampling time to form a segment status combination; wherein the segment status combination includes segment name, sampling time, valve opening deviation, hydraulic motor pressure status, servo valve drive status, and sequence number within the segment.

[0034] Preferably, the segmented state combination does not change the original sampling order in the valve action state sequence, which facilitates the subsequent determination of the relationship between the valve opening deviation and the servo valve drive state, as well as the relationship between the hydraulic motor pressure state and the valve opening deviation.

[0035] For example, if the sampling time of the starting segment is 10:15:20.120 and the sampling time of the starting segment is 10:15:20.180, then the valve opening deviation, hydraulic motor pressure status and servo valve drive status of 7 sampling positions are extracted from this time range and arranged at 10ms intervals to form the segment status combination corresponding to the starting segment.

[0036] S2.2. Based on the relationship between the valve opening deviation and the servo valve drive state in the segmented state combination, determine the valve opening response relationship; when the servo valve drive state has changed and the valve opening deviation increases in the continuous sampling position, determine the valve opening response relationship as the valve response lag relationship.

[0037] Specifically, first, it is determined whether the servo valve drive state has changed from a stable drive state to an increased drive state or a decreased drive state; then, it is determined whether the valve opening deviation has increased within the continuous sampling positions after the change in the servo valve drive state; in this embodiment, the increase refers to: within three consecutive sampling positions after the change in the servo valve drive state, the absolute value of the valve opening deviation increases successively, and the increase at the third sampling position relative to the first sampling position is not less than 0.5%; when the valve opening deviation meets the above-mentioned increase condition, the valve opening response relationship is determined as the valve response lag relationship.

[0038] When the servo valve drive state has changed, and the absolute value of the valve opening deviation decreases successively in three consecutive sampling positions, and the decrease in the third sampling position relative to the first sampling position is not less than 0.5%, the valve opening response relationship is determined to be a valve response convergence relationship; when the servo valve drive state has changed, and the absolute value change of the valve opening deviation in three consecutive sampling positions is less than 0.2%, the valve opening response relationship is determined to be a valve response stagnation relationship; when the servo valve drive state has not changed and the valve opening deviation increases, the valve opening response relationship is determined to be a drive disengagement relationship.

[0039] For example, in a certain large-scale adjustment, the servo valve drive state increases from 12.0mA to 13.2mA at 10:15:20.130. Subsequently, the valve opening deviations at three sampling positions are 1.0%, 1.4%, and 1.7%, respectively. The third sampling position increases by 0.7% relative to the first sampling position. Therefore, the valve opening response relationship is determined to be a valve response hysteresis relationship. This relationship indicates that the servo valve has generated a drive change, but the high-pressure valve has not reduced the opening deviation in the drive direction.

[0040] S2.3. Based on the relationship between the change in hydraulic motor pressure state and valve opening deviation in the segmented state combination, determine the hydraulic motor pressure relationship; when the hydraulic motor pressure state has formed a pressure increase state or a pressure decrease state, and the valve opening deviation does not converge with the hydraulic motor pressure state, the hydraulic motor pressure relationship is determined to be an abnormal pressure relationship.

[0041] Specifically, first, it is determined whether the hydraulic actuator pressure has reached a boosting or depressurizing state; then, it is determined whether the valve opening deviation converges with the hydraulic actuator pressure state. In this embodiment, convergence means that within five consecutive sampling positions after the hydraulic actuator pressure reaches a boosting or depressurizing state, the absolute value of the valve opening deviation generally decreases, and the decrease at the fifth sampling position relative to the first sampling position is not less than 0.6%. At the same time, within these five consecutive sampling positions, the absolute value of the valve opening deviation must not increase twice consecutively, and the increase each time must not exceed 0.2%.

[0042] When the hydraulic actuator pressure has reached a boosting or depressurizing state, but the valve opening deviation does not meet the above convergence conditions, the hydraulic actuator pressure connection relationship is determined to be an abnormal pressure connection relationship; when the hydraulic actuator pressure has reached a boosting or depressurizing state, and the valve opening deviation meets the above convergence conditions, the hydraulic actuator pressure connection relationship is determined to be a normal pressure connection relationship; when the hydraulic actuator pressure has not reached a boosting or depressurizing state, but the servo valve drive state has reached an increasing or decreasing drive state, the hydraulic actuator pressure connection relationship is determined to be a pressure non-response relationship.

[0043] For example, during a high-pressure valve opening process, the hydraulic actuator pressure changed from a stable state to a boosting state at 10:15:20:150. Subsequently, the valve opening deviations at five sampling locations were 1.8%, 1.9%, 2.0%, 2.1%, and 2.2%, respectively. The valve opening deviation did not decrease with the decrease in hydraulic actuator pressure; instead, it increased continuously. Therefore, the hydraulic actuator pressure connection relationship was determined to be an abnormal pressure connection relationship. This relationship indicates that although the hydraulic actuator had generated a boosting state, the high-pressure valve opening deviation did not decrease with hydraulic drive, and the cause of the fault was closer to the hydraulic actuator, valve linkage, or valve actuator side.

[0044] S2.4. Generate valve status labels based on the valve opening response relationship and the hydraulic actuator pressure connection relationship: When the valve opening response relationship is a valve response lag relationship and the hydraulic actuator pressure connection relationship is an abnormal pressure connection relationship, an actuator abnormal label is generated. When the valve opening response relationship is a valve response lag relationship and the hydraulic motor pressure connection relationship does not form an abnormal pressure connection relationship, a servo drive deviation label is generated. When the valve opening deviation converges with the hydraulic motor pressure state, a normal valve following label is generated.

[0045] It should be noted that by using the above process, the valve opening deviation is correlated with the servo valve drive status and the hydraulic actuator pressure status within a segment, which solves the problem that the valve opening deviation alone cannot distinguish between servo drive deviation and actuator abnormality. As a result, valve status labels oriented towards the source of the fault can be formed during the high-pressure valve load adjustment process, providing a direct basis for the selection of subsequent control correction amounts and reducing the situation of misjudging mechanical jamming as control parameter deviation.

[0046] S3. Based on the valve action segmentation index, perform consistency determination on the status of the speed acquisition channel, valve position feedback channel, and servo drive channel in the turbine speed control system, and generate link status tags. Note that the following points should be noted in this step: S3.1. According to the valve action segment index, extract the speed acquisition channel status, valve position feedback channel status and servo drive channel status from the start segment, follow segment, pressure segment and return segment respectively to form a segment channel status combination.

[0047] Specifically, the speed acquisition channel status is obtained from the turbine speed sensor, speed acquisition module, and turbine speed controller speed input terminal. The speed acquisition channel status includes normal speed change status, speed stagnation status, and speed sudden change status. The valve position feedback channel status is obtained from the valve position sensor, valve position signal isolation module, and turbine speed controller valve position input terminal. The valve position feedback channel status includes synchronous valve position change status, stagnant valve position, jump valve position, and discontinuous valve position. The servo drive channel status is obtained from the servo drive module control output terminal, servo valve coil current detection unit, and servo drive feedback terminal. The servo drive channel status includes normal drive change status, stagnant drive status, jump drive status, and discontinuous drive status.

[0048] Furthermore, the method for extracting the speed acquisition channel status, valve position feedback channel status, and servo drive channel status from the starting segment, following segment, pressure-bearing segment, and return segment is as follows: Based on the segment start sampling time and segment end sampling time in the valve action segment index, the speed acquisition channel status, valve position feedback channel status, and servo drive channel status corresponding to each sampling position are retrieved from the same judgment window of the turbine speed controller; arranged in the order of sampling time to form a segment channel status combination; wherein the segment channel status combination includes segment name, sampling time, speed acquisition channel status, valve position feedback channel status, servo drive channel status, and sequence number within the segment.

[0049] Preferably, the segmented channel state combination and the segmented state combination use the same segment name and the same sampling time range, which facilitates the subsequent cross-verification of channel-side anomalies and gate execution-side anomalies.

[0050] S3.2. Based on the relationship between the changes in the speed acquisition channel state and the valve position feedback channel state in the segmented channel state combination, determine the acquisition feedback consistency relationship; when the valve position feedback channel state changes synchronously with the actual opening of the regulating valve, and the speed acquisition channel state does not show a stagnant or abrupt state, the acquisition feedback consistency relationship is determined as the acquisition feedback normal relationship.

[0051] Specifically, in the follow-up segment and the return segment, when the valve position feedback channel status changes synchronously with the actual opening of the control valve, and the speed acquisition channel status does not show a speed stagnation state or a speed change state, the acquisition feedback consistency relationship is determined to be the acquisition feedback normal relationship.

[0052] The valve position feedback channel state changes synchronously with the actual opening of the control valve. This means that the direction of change of the valve position feedback channel state is consistent with the direction of change of the actual opening of the control valve, and the starting points of the two changes are no more than 2 sampling positions apart. When the actual opening of the control valve is in the open state, the valve position feedback channel state is also in the valve position synchronously increasing state. When the actual opening of the control valve is in the closed state, the valve position feedback channel state is also in the valve position synchronously decreasing state.

[0053] Furthermore, the determination rule for the speed stagnation state in this embodiment is as follows: during the load adjustment process, the actual opening degree of the regulating valve has changed continuously, and under the background that the pressure in front of the turbine main steam valve and the unit load command have both changed, the speed change in the speed acquisition channel is less than 1 r / min in 5 consecutive sampling positions.

[0054] Furthermore, the determination rule for sudden speed change in this embodiment is as follows: if the change in the speed acquisition channel state is greater than 20 r / min between two adjacent sampling positions, and the valve position feedback channel state and the actual valve opening do not show a corresponding synchronous change; if the valve position feedback channel state remains unchanged for four consecutive sampling positions, while the actual valve opening or servo valve drive state has changed continuously, the valve position feedback channel state is determined to be in a valve position stagnation state; if the change in the valve position feedback channel state is greater than 1.0% between two adjacent sampling positions, and the servo valve drive state and the hydraulic actuator pressure state do not show a corresponding successive change, the valve position feedback channel state is determined to be in a valve position jump state.

[0055] For example, during a high-pressure regulating valve opening process, the actual valve opening increased from 42.1% to 44.0%, and the valve position feedback channel status increased from 42.0% to 43.9%, with the starting points of the two changes differing by one sampling position. At the same time, the change in the speed acquisition channel status between each sampling position was within the range of 2 r / min to 8 r / min, without any state of five consecutive sampling positions less than 1 r / min, or any state of two adjacent sampling positions greater than 20 r / min. In this case, the consistent acquisition feedback relationship is determined to be a normal acquisition feedback relationship.

[0056] S3.3. Based on the change relationship between the servo drive channel state and the valve position feedback channel state in the segmented channel state combination, determine the drive feedback consistency relationship; when the servo drive channel state has changed but the valve position feedback channel state has not changed with the servo drive channel state, the drive feedback consistency relationship is determined to be the drive feedback abnormal relationship.

[0057] Specifically, first determine whether the servo drive channel state has entered the drive change process from the normal drive change state, the drive stable state, or the drive stagnation state; then determine whether the valve position feedback channel state forms a same-direction change within 5 consecutive sampling positions after the servo drive channel state changes; when the servo drive channel state has changed, but the valve position feedback channel state does not form a same-direction change with the servo drive channel state within 5 consecutive sampling positions, the drive feedback consistency relationship is determined to be a drive feedback abnormal relationship.

[0058] When the servo drive channel state is increasing drive change, and the valve position feedback channel state forms a synchronous increase in valve position within 5 consecutive sampling positions, the drive feedback consistency relationship is determined to be a normal drive feedback relationship. When the servo drive channel state is decreasing drive change, and the valve position feedback channel state forms a synchronous decrease in valve position within 5 consecutive sampling positions, the drive feedback consistency relationship is also determined to be a normal drive feedback relationship. When the change in servo drive channel state between two adjacent sampling positions is greater than 2.0mA, and the valve opening command output by the turbine speed controller does not form a corresponding directional change, the servo drive channel state is determined to be a drive jump state, and the drive feedback consistency relationship is determined to be an abnormal drive feedback relationship.

[0059] For example, the servo drive channel status increases from 12.0mA to 13.5mA at 10:15:20.130 and continues to increase in drive state in the subsequent 5 sampling positions. Meanwhile, the valve position feedback channel status remains at 42.1%, 42.1%, 42.1%, 42.1%, and 42.1% during the same period, without forming a synchronous increase in valve position. In this case, the drive feedback consistency relationship is determined to be an abnormal drive feedback relationship. This relationship indicates that the servo drive change does not form a corresponding change on the valve position feedback side. There may be a servo drive channel discontinuity, a stagnant valve position feedback channel, or mechanical blockage of the actuator. Further cross-checking is required in conjunction with the valve status label in step S2.

[0060] S3.4. Generate link status labels based on the consistency relationship between data collection feedback and the consistency relationship between driver feedback: When the data collection feedback consistency relationship is a normal data collection feedback relationship and the driving feedback consistency relationship does not form an abnormal driving feedback relationship, a normal link label is generated. When the data collection and feedback consistency relationship fails to form a normal data collection and feedback relationship, an abnormal data collection and feedback label is generated. When the drive feedback consistency relationship is a drive feedback abnormal relationship, a servo drive link abnormal label is generated.

[0061] It should be noted that by determining the consistency of the same segment based on the valve action segment index for the speed acquisition channel status, valve position feedback channel status, and servo drive channel status, the problem of confusion between channel-side anomalies and execution-side anomalies in high-pressure valve opening deviation fault monitoring is solved. It can identify whether the valve opening deviation comes from an actual execution action anomaly or from an anomaly in the valve position feedback, speed acquisition, or servo drive channel, reducing the risk of speed control system oscillation caused by error compensation.

[0062] S4. Cross-check the valve status label with the link status label to generate the valve control correction value, and send it to the turbine speed controller. Note that the following should be noted in this step: S4.1. According to the order of fragmentation in the damper action fragmentation index, merge the damper status label and link status label of the same fragment to form a label verification combination. The label verification combination includes the fragmentation name, damper status label and link status label.

[0063] Specifically, the order of segments in the valve action segment index is the actual order in which each segment appears in the valve action state sequence; in a complete load regulation process, the sequence is usually: starting segment, following segment, and return segment; when there is no pressure opening connection, a pressure-bearing segment is inserted at the actual position to form a starting segment, pressure-bearing segment, following segment, and return segment, or a starting segment, following segment, pressure-bearing segment, and return segment.

[0064] In this embodiment, the merging method in step S4.1 is as follows: based on the segment name, segment start sampling time, and segment end sampling time in the segment index of the gate action, the gate status label and link status label generated in the same segment are merged into the same label verification combination; the label verification combination includes the segment name, segment start sampling time, segment end sampling time, gate status label, link status label, abnormal occurrence location, and verification conclusion.

[0065] Among them, the anomaly first occurrence position is the sampling position where the anomaly label appears earliest within the same segment; when the gate status label becomes abnormal earlier than the link status label, the anomaly first occurrence position is recorded as the gate side first occurrence; when the link status label becomes abnormal earlier than the gate status label, the anomaly first occurrence position is recorded as the channel side first occurrence; when both become abnormal at the same sampling position, the anomaly first occurrence position is recorded as the synchronization anomaly.

[0066] S4.2. Perform cross-verification of the tuning status label and the link status label in the label verification combination: When the valve status label is the actuator abnormal label and the link status label is the link normal label, the fault source is determined to be on the actuator side; When the valve status label is the actuator abnormal label and the link status label is the data acquisition feedback abnormal label, the source of the fault is determined to be the feedback channel side. When the gate status label is a servo drive deviation label and the link status label is a servo drive link abnormal label, the fault source is determined to be on the servo drive channel side.

[0067] S4.3 Determine the control correction amount of the regulating valve based on the source of the fault: When the source of the fault is on the actuator side, the control correction amount of the regulating gate is determined as the regulating gate opening compensation amount; When the fault originates from the feedback channel side or the servo drive channel side, the adjustment gate control correction amount is determined as the adjustment gate opening holding amount; When the regulating valve status label is the regulating valve following normal label and the link status label is the link normal label, the regulating valve control correction amount is determined as the speed regulation parameter holding amount.

[0068] Specifically, when the control correction type is valve opening compensation, the valve opening compensation amount is generated according to the direction of the valve opening deviation; the direction of the valve opening compensation amount is consistent with the convergence direction of the valve opening deviation, the single compensation amplitude is no greater than 0.5%, and the cumulative compensation amplitude within the same following segment is no greater than 1.5%; when the control correction type is valve opening maintenance, a valve opening maintenance amount is generated, which uses the valve opening command value at the current sampling position, and no further opening or closing commands are added within the pressure-bearing segment; this processing is suitable for The system detects mechanical jamming or hydraulic motor immobilization corresponding to the abnormal actuator label, preventing further increase in servo drive pressure and subsequent hydraulic shock. When the control correction type is speed parameter maintenance, a speed parameter maintenance value is generated. This value uses the speed parameter group from the previous sampling position before entering the segment, which includes speed gain parameters, speed integral correction parameters, and speed change suppression parameters. This process is suitable for collecting feedback abnormal labels or servo drive link abnormal labels corresponding to channel abnormal states, preventing the introduction of erroneous channel signals into the speed correction process.

[0069] S4.4 Associate the control correction amount of the regulating valve with the regulating valve action segment index, and send the control correction amount of the regulating valve to the turbine speed controller.

[0070] Specifically, the control correction amount of the regulating valve is matched one-to-one with the segment name, segment start sampling time, segment end sampling time, regulating valve status label, link status label, and control correction type that generate the correction amount, forming a regulating valve control correction combination. The segment name in the regulating valve control correction combination comes from the regulating valve action segment index, the regulating valve status label comes from step S2, the link status label comes from step S3, the control correction type comes from step S4.2, and the regulating valve control correction amount comes from step S4.3. The regulating valve control correction combination is arranged in the order of the segments in the regulating valve action segment index, so that the turbine speed controller can receive the corresponding correction content according to the action stage of the load regulation process.

[0071] Furthermore, the fault monitoring unit sends the valve control correction combination to the valve correction input terminal of the turbine speed controller. After receiving the valve control correction combination, the turbine speed controller first compares the segment name and the current sampling time to confirm that the current sampling time is between the starting sampling time and the ending sampling time of the corresponding segment. Then, it adopts the corresponding valve control correction amount according to the control correction type. For the valve opening compensation type, the turbine speed controller adds the valve opening compensation amount to the current valve opening command. For the valve opening maintenance type, the turbine speed controller uses the valve opening maintenance amount to replace the continuously changing valve opening command. For the speed parameter maintenance type, the turbine speed controller uses the speed parameter group corresponding to the speed parameter maintenance amount and suspends the adjustment of speed parameters based on the valve position feedback changes within the segment.

[0072] For example, during the load increase from 450MW to 465MW in a thermal power unit, the high-pressure regulating valve opening command increases from 42.0% to 46.0%. During the start-up segment from 10:15:20.120 to 10:15:20.180, the regulating valve status label is a servo drive deviation label, the link status label is a link normal label, and the control correction type is regulating valve opening compensation, generating a 0.4% regulating valve opening compensation amount. The fault monitoring unit associates the regulating valve opening compensation amount with the segment start sampling time of 10:15:20.120 and the segment end sampling time of 10:15:20.180, and sends it to the turbine speed controller. After receiving the regulating valve control correction combination at 10:15:20.160, the turbine speed controller corrects the current regulating valve opening command from 44.2% to 44.6%.

[0073] For example, within the pressure-bearing segment from 10:15:20.190 to 10:15:20.260, the valve status label is the actuator abnormal label, the link status label is the link normal label, and the control correction type is the valve opening maintenance type, generating a valve opening maintenance amount of 44.6%. After receiving the valve opening maintenance amount, the turbine speed controller uses 44.6% as the valve opening command within the pressure-bearing segment, pausing the command to continue increasing the valve opening, thus preventing the hydraulic actuator from continuing to bear higher driving pressure when the pressure has increased but the valve has not acted.

[0074] For example, within the following segment from 10:15:20.270 to 10:15:20.350, the link status label is the acquisition feedback abnormal label, the valve status label is the abnormal state corresponding to the valve response lag relationship, and the control correction type is the speed parameter maintenance type. The turbine speed controller uses the speed gain parameter, speed integral correction parameter, and speed change suppression parameter from the previous sampling position before entering this following segment, and no longer increases the valve opening compensation amount based on the abnormal valve position feedback change within this following segment.

[0075] It should be noted that by cross-checking the valve status label and the link status label within the same valve action segment, and converting the verification results into valve opening compensation, valve opening maintenance, or speed control parameter maintenance, the problem of unclear fault sources leading to incorrect correction direction during high-pressure valve opening deviation correction is solved. This enables the formation of differentiated control correction strategies among servo drive deviation, actuator abnormality, and channel abnormality, reducing the risks of valve overcompensation, hydraulic motor pressure shock, and speed control parameter misadjustment.

[0076] 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 method for fault monitoring and control correction in a steam turbine speed control system, characterized in that, include: Based on the sequential and consistent relationship between the valve opening command, the actual valve opening, the hydraulic motor pressure state, and the servo valve drive state in the turbine speed control system, the valve action process is divided and a valve action segment index is generated. Generating the valve action segment index includes: synchronously arranging the valve opening command, actual valve opening, hydraulic actuator pressure status, and servo valve drive status in the turbine speed control system at the same sampling time to form a valve action state sequence; generating the valve action sequence relationship based on the changing positions of the valve opening command, servo valve drive status, hydraulic actuator pressure status, and actual valve opening in the valve action state sequence; generating the valve action change consistency relationship based on the changing direction and amplitude of the valve opening command, actual valve opening, hydraulic actuator pressure status, and servo valve drive status in the valve action state sequence; and dividing the valve action state sequence into starting segment, following segment, pressure-bearing segment, and return segment according to the segment sequence to generate a valve action segment index. Based on the valve action segment index, the valve opening deviation, hydraulic motor pressure status and servo valve drive status in the turbine speed control system are correlated and determined to generate valve status labels. Based on the valve action segmentation index, the consistency of the speed acquisition channel status, valve position feedback channel status and servo drive channel status in the turbine speed control system is determined, and a link status label is generated. The valve status label and the link status label are cross-checked to generate a valve control correction value, which is then sent to the turbine speed controller. Generating the control adjustment amount includes: merging the control status label and the link status label of the same segment according to the segmentation order in the control action segmentation index to form a label verification combination, wherein the label verification combination includes a segmentation name, a control status label, and a link status label; performing cross-verification on the control status label and the link status label in the label verification combination; when the control status label is an actuator abnormal label and the link status label is a link normal label, the fault source is determined to be on the actuator side; when the control status label is an actuator abnormal label and the link status label is a data acquisition feedback abnormal label, the fault source is determined to be on the feedback channel side; when the control status label is... When the servo drive deviation label and the link status label are both servo drive link abnormal labels, the fault source is determined to be on the servo drive channel side; the valve control correction amount is determined based on the fault source; when the fault source is on the actuator side, the valve control correction amount is determined to be the valve opening compensation amount; when the fault source is on the feedback channel side or the servo drive channel side, the valve control correction amount is determined to be the valve opening holding amount; when the valve status label is the valve following normal label and the link status label is the link normal label, the valve control correction amount is determined to be the speed regulation parameter holding amount; the valve control correction amount is associated with the valve action segment index, and the valve control correction amount is sent to the turbine speed controller.

2. The fault monitoring and control correction method for a steam turbine speed regulation system according to claim 1, characterized in that, The sequence of valve actions includes the order in which the positions of the valve opening command, the servo valve drive state, the hydraulic actuator pressure state, and the actual valve opening position change are arranged in the valve action state sequence; wherein: The change position of the regulating valve opening command is the sampling position where the regulating valve opening command changes from a holding state to an increasing state or a decreasing state; the change position of the servo valve drive state is the sampling position where the servo valve drive state changes from a holding state to an increasing drive state or a decreasing drive state; the change position of the hydraulic actuator pressure state is the sampling position where the hydraulic actuator pressure state changes from a holding state to a pressurizing state or a depressurizing state; and the change position of the actual regulating valve opening is the sampling position where the actual regulating valve opening changes from a holding state to a wide open state or a narrow closed state. When the position of the change of the valve opening command, the position of the change of the servo valve drive state, the position of the change of the hydraulic motor pressure state, and the position of the change of the actual valve opening are arranged in sequence, a command drive pressure opening succession relationship is generated. When the change position of the servo valve drive state is earlier than the change position of the valve opening command, or the change position of the actual valve opening is earlier than the change position of the hydraulic actuator pressure state, an abnormal sequence relationship is generated. When the change in the pressure state of the hydraulic actuator has occurred but the change in the actual opening of the regulating valve has not occurred, a pressure without opening continuity relationship is generated.

3. The fault monitoring and control correction method for a steam turbine speed regulation system according to claim 1, characterized in that, The consistent relationship of the adjustment valve movement includes the consistent relationship of the change direction and the continuity relationship of the change amplitude; wherein: The consistent direction of change is determined by the increase, decrease, or maintenance of the valve opening command, the servo valve drive state, the hydraulic actuator pressure state, and the actual valve opening between adjacent sampling positions. A positive continuity relationship is generated when the valve opening command and the servo valve drive state change direction are consistent, and the hydraulic actuator pressure state and the actual valve opening change direction follow the direction of the servo valve drive state change. A directional deviation relationship is generated when the valve opening command and the servo valve drive state change direction are consistent, but the hydraulic actuator pressure state or the actual valve opening change direction does not follow the direction of the servo valve drive state change. The change amplitude continuity relationship is determined by the change amplitude of the valve opening command, the servo valve drive state, the hydraulic motor pressure state, and the actual valve opening between adjacent sampling positions; when the change amplitude is transmitted sequentially according to the valve action sequence, a continuous amplitude relationship is generated; when any change amplitude changes in the opposite direction or stagnates at an adjacent continuity position, a discontinuous amplitude relationship is generated.

4. The fault monitoring and control correction method for a steam turbine speed regulation system according to claim 1, characterized in that, The sequence of valve action states is divided into starting segment, following segment, pressure-bearing segment, and return segment, including: When the sequence of valve actions is a command-driven pressure opening succession relationship, and the valve opening command changes from a holding state to an increasing state or a decreasing state, and the servo valve driving state changes to an increasing driving state or a decreasing driving state according to the valve opening command, but the actual valve opening has not yet formed a continuous opening state or a continuous closing state, the valve action state sequence is divided into the starting segment. When the relationship between the changes in the valve action is a positive succession relationship, and the direction of change of the actual opening of the valve is consistent with the direction of change of the valve opening command, and the range of change of the actual opening of the valve is continuously succeeded according to the range of change of the valve opening command, the valve action state sequence is divided into the following segments. When the pressure state of the hydraulic actuator has changed to a pressure increase state or a pressure decrease state, the drive state of the servo valve remains in an increase drive state or a decrease drive state, and the change range of the actual opening of the regulating valve does not change continuously with the pressure state of the hydraulic actuator, the sequence of the regulating valve action state is divided into the pressure-bearing segments. When the valve opening command changes from an increasing or decreasing state to a holding state, or when the direction of change of the valve opening command changes in the opposite direction, and the actual valve opening returns to the opening position indicated by the valve opening command, the valve action state sequence is divided into the return segment.

5. The fault monitoring and control correction method for a steam turbine speed regulation system according to claim 4, characterized in that, Generating the gate status label includes: According to the valve action segment index, extract the valve opening deviation, hydraulic motor pressure state and servo valve drive state from the starting segment, the following segment, the pressure bearing segment and the return segment respectively to form a segment state combination; Based on the relationship between the valve opening deviation and the servo valve drive state in the segmented state combination, the valve opening response relationship is determined; when the servo valve drive state has changed and the valve opening deviation increases in the continuous sampling position, the valve opening response relationship is determined to be a valve response lag relationship. Based on the relationship between the change in hydraulic motor pressure state and valve opening deviation in the segmented state combination, the hydraulic motor pressure relationship is determined; when the hydraulic motor pressure state has formed a pressure increase state or a pressure decrease state, and the valve opening deviation does not converge with the hydraulic motor pressure state, the hydraulic motor pressure relationship is determined to be an abnormal pressure relationship. The valve status label is generated based on the valve opening response relationship and the hydraulic actuator pressure support relationship.

6. The fault monitoring and control correction method for a steam turbine speed regulation system according to claim 5, characterized in that, The regulating valve status label includes: When the valve opening response relationship is a valve response lag relationship and the hydraulic actuator pressure connection relationship is an abnormal pressure connection relationship, an actuator abnormality label is generated. When the valve opening response relationship is a valve response lag relationship and the hydraulic motor pressure connection relationship does not form an abnormal pressure connection relationship, a servo drive deviation label is generated. When the valve opening deviation converges with the hydraulic motor pressure state, a valve following normal label is generated.

7. The fault monitoring and control correction method for a steam turbine speed regulation system according to claim 6, characterized in that, Generating the link status label includes: According to the valve action segment index, the speed acquisition channel status, valve position feedback channel status, and servo drive channel status in the starting segment, the following segment, the pressure bearing segment, and the return segment are extracted respectively to form a segment channel status combination; Based on the change relationship between the speed acquisition channel state and the valve position feedback channel state in the segmented channel state combination, the acquisition feedback consistency relationship is determined; when the valve position feedback channel state changes synchronously with the actual opening of the regulating valve, and the speed acquisition channel state does not show a stagnant state or a sudden state, the acquisition feedback consistency relationship is determined to be the acquisition feedback normal relationship. Based on the change relationship between the servo drive channel state and the valve position feedback channel state in the segmented channel state combination, the drive feedback consistency relationship is determined; when the servo drive channel state has changed but the valve position feedback channel state has not changed with the servo drive channel state, the drive feedback consistency relationship is determined to be a drive feedback abnormal relationship. The link status label is generated based on the consistency relationship between the collected feedback and the driving feedback.

8. The fault monitoring and control correction method for a steam turbine speed regulation system according to claim 7, characterized in that, The link status label includes: When the acquisition feedback consistency relationship is a normal acquisition feedback relationship and the driving feedback consistency relationship does not form a driving feedback abnormal relationship, a link normal label is generated; When the data collection and feedback consistency relationship fails to form a normal data collection and feedback relationship, a data collection and feedback abnormality label is generated. When the drive feedback consistency relationship is a drive feedback abnormal relationship, a servo drive link abnormal label is generated.

Images