A control method and related device for active assistance in closing a turbine extraction non-return valve based on differential pressure prediction

Abstract

The application discloses a kind of based on differential pressure pre-judgment's steam turbine extraction check valve active help closing control method, steam turbine extraction check valve active help closing control device, active help closing control equipment, computer readable storage medium, the method acquisition extraction side pressure, high pressure heater side pressure, unit load, isolation valve state, check valve position feedback and help closing actuator available signal;Two sides pressure is filtered, and pressure difference, reference pressure and relative pressure difference are calculated;According to load, valve state and actuator state, pre-help closing permission signal is generated;During the effective period of this signal, when pressure difference is greater than zero and relative pressure difference is less than zero trend threshold and continuously reaches holding time, pressure difference zero trend risk signal is generated, pre-help closing instruction is output, and extraction check valve is driven to move in the direction of closing.The application can start help closing before pressure difference reverses, reduce medium backflow risk under deep peak shaving and fast load change condition.

Description

Technical Field

[0001] This invention belongs to the field of steam turbine control technology, and more specifically, relates to a steam turbine extraction non-return valve active auxiliary closing control method based on differential pressure prediction, a steam turbine extraction non-return valve active auxiliary closing control device, an active auxiliary closing control equipment, and a computer-readable storage medium. Background Technology

[0002] The turbine extraction steam regeneration system introduces steam from the corresponding extraction section of the turbine into the high-pressure heater through the extraction steam pipeline to increase the feedwater temperature and improve unit operating efficiency. To prevent the medium on the high-pressure heater side from flowing back into the turbine under abnormal operating conditions, the extraction steam pipeline is usually equipped with extraction non-return valves with mechanical non-return and actuator-assisted closing functions. Under normal steam supply, the valve disc opens under the action of forward flow and pressure difference; when the extraction steam flow decreases or the pressure difference reverses, the valve disc returns to its seat by gravity, spring force, and the force of the medium, and the distributed control system controls the actuator to close it faster.

[0003] Existing auxiliary control systems typically use outcome-based signals such as turbine tripping and high-pressure heater water level as triggering conditions. Their main drawback is that the action criteria are formed relatively late, making it difficult to identify intermediate risk states where the extraction steam pressure drops rapidly, the high-pressure heater pressure drops relatively slowly, and the pressure difference has not yet reversed. During deep peak shaving with low flow rates and rapid load reduction, the valve disc may be in an unstable state. When the pressure difference rapidly approaches zero, the outcome-based interlock has not yet been triggered, and the extraction steam non-return valve may not be able to reseat in time before backflow occurs.

[0004] Therefore, there is a need for an active auxiliary closing control method that makes advance judgments based on the changes in pressure difference between the two sides. When the positive pressure difference still exists but has entered a state approaching zero, the auxiliary closing action is triggered, causing the extraction non-return valve to move in the closing direction in advance, so as to reduce the risk of medium backflow. Summary of the Invention

[0005] The purpose of this application is to provide a method for active auxiliary closing control of a turbine extraction non-return valve based on differential pressure prediction, a device for active auxiliary closing control of a turbine extraction non-return valve, an active auxiliary closing control device, and a computer-readable storage medium, so as to trigger the auxiliary closing action when the positive differential pressure still exists but has entered a state approaching zero, so as to make the extraction non-return valve move in the closing direction in advance to reduce the risk of medium backflow.

[0006] To address the aforementioned deficiencies or improvement needs of existing technologies, this invention provides a method for active auxiliary closing control of a turbine extraction non-return valve based on differential pressure prediction, comprising: S1 collects the extraction steam side pressure upstream of the extraction steam non-return valve, the high-pressure heater side pressure connected to the extraction steam pipeline, the unit load, the status of the extraction steam electric isolation valve, the valve position feedback of the extraction steam non-return valve, and the available signals of the auxiliary closing actuator. S2, the extraction steam side pressure and the high-pressure heater side pressure are filtered, the difference between the filtered extraction steam side pressure and the high-pressure heater side pressure is determined as the pressure difference, the larger value between the high-pressure heater side pressure and the preset low pressure lower limit is determined as the reference pressure, and the relative pressure difference is determined according to the ratio of the pressure difference to the reference pressure. S3, based on the fact that the unit load is lower than the preset operating load, the extraction steam electric isolation valve is in the open position, the extraction steam non-return valve is in the open position, and the auxiliary closing actuator is available, a pre-auxiliary closing permission signal is generated; S4, during the effective period of the pre-assistance allow signal, determine whether the pressure difference is greater than zero and whether the relative pressure difference is less than a preset zero-reaching threshold, and generate a pressure difference zero-reaching risk signal when the above determination results are continuously true for a preset holding time. S5, in response to the risk signal that the differential pressure approaches zero, outputs a pre-assisted closing command and controls the closing actuator to move so as to drive the extraction steam non-return valve to move in the closing direction when the differential pressure is still positive.

[0007] Optionally, in S1, the extraction steam side pressure is taken from the pressure measuring point upstream of the extraction steam non-return valve or on the extraction steam pipeline side, and the high-pressure heater side pressure is taken from the pressure measuring point on the high-pressure heater shell side or on the side where the high-pressure heater is connected to the extraction steam pipeline; in S2, the extraction steam side pressure and the high-pressure heater side pressure are filtered or de-jittered using a distributed control system, and the pressure difference and the relative pressure difference are calculated using the processed pressure values.

[0008] Optionally, the extraction steam side pressure is denoted as P_ext, the high-pressure heater side pressure as P_heater, the pressure difference as ΔP, the reference pressure as P_ref, and the relative pressure difference as δ. Then: ΔP = P_ext - P_heater; P_ref=max(P_heater,P_min); δ = ΔP / P_ref; Wherein, P_min is the preset low-pressure lower limit, with a value of 0.5MPa to 1MPa; the preset zero-reach threshold is 0.5% to 2%; and the preset holding time is 0.2s to 0.5s.

[0009] Optionally, in step S3, the preset operating load is 40% of the unit's rated load; the extraction non-return valve is determined to be in the open state based on the effective feedback of the fully open valve and the ineffective feedback of the fully closed valve; when the auxiliary closing actuator is a pneumatic auxiliary closing actuator, the auxiliary closing actuator is determined to be usable based on the air source pressure not being lower than 0.4 MPa; when the auxiliary closing actuator is a hydraulic auxiliary closing actuator, the auxiliary closing actuator is determined to be usable based on the hydraulic pressure reaching the preset pressure or the hydraulic auxiliary closing actuator's ready signal being effective.

[0010] Optionally, S3 further includes: acquiring a rapid operating condition indication signal and using the rapid operating condition indication signal as an additional condition for generating the pre-shutdown permission signal; wherein the rapid operating condition indication signal includes at least one of an RB signal, a rapid load reduction signal, and a signal generated when the unit load reduction rate reaches a preset rate threshold.

[0011] Optionally, S5 includes: performing an OR logic operation on the pre-assisted closing command and the resulting assisted closing command generated based on the turbine trip signal and / or the high-high water level signal of the high-pressure heater to generate a general assisted closing command; controlling the switching of the assisted closing solenoid valve according to the general assisted closing command to quickly release the pneumatic pressure maintaining the opening of the extraction steam non-return valve, or to unload the hydraulic pressure maintaining the opening of the extraction steam non-return valve, so that the extraction steam non-return valve moves towards the valve seat under the action of spring force and / or gravity.

[0012] Optionally, after outputting the auxiliary closing command, a response timer is started, and feedback on the full closure of the extraction non-return valve is obtained; when a valid full closure feedback is obtained within a preset response time, the closure of the extraction non-return valve is recorded; when a valid full closure feedback is not obtained within the preset response time, valve closure abnormality information is output, including at least one of alarm information, action event record, and maintenance prompt.

[0013] This application also provides an active auxiliary closing control device for a turbine extraction non-return valve based on differential pressure prediction, comprising: The signal acquisition module is used to collect the extraction steam side pressure upstream of the extraction steam non-return valve, the high-pressure heater side pressure connected to the extraction steam pipeline, the unit load, the status of the extraction steam electric isolation valve, the valve position feedback of the extraction steam non-return valve, and the available signals of the auxiliary closing actuator. The signal processing module is used to filter the extraction steam side pressure and the high-pressure heater side pressure, determine the difference between the filtered extraction steam side pressure and the high-pressure heater side pressure as the pressure difference, determine the larger value between the high-pressure heater side pressure and the preset low pressure lower limit as the reference pressure, and determine the relative pressure difference based on the ratio of the pressure difference to the reference pressure. The signal generation module is used to generate a pre-assisted closing permission signal based on the following conditions: the unit load is lower than the preset commissioning load, the extraction steam electric isolation valve is in the open position, the extraction steam non-return valve is in the open position, and the auxiliary closing actuator is available. The zero-risk signal generation module is used to determine whether the differential pressure is greater than zero and whether the relative differential pressure is less than a preset zero-approaching threshold during the effective period of the pre-assistance allow signal, and to generate a differential pressure approaching zero risk signal when the above determination results are continuously true for a preset holding time. The control module is used to output a pre-closing command in response to the differential pressure approaching zero risk signal, and control the closing actuator to drive the extraction steam non-return valve to move in the closing direction when the differential pressure is still positive.

[0014] This application also provides an active assistance control device, including: Memory, used to store computer programs; A processor is used to execute the computer program to implement the steps of the active auxiliary closing control method for the steam turbine extraction non-return valve as described above.

[0015] This application also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the active auxiliary closing control method for the steam turbine extraction non-return valve as described above.

[0016] It has the following beneficial effects: By simultaneously collecting extraction steam side pressure, high-pressure heater side pressure, unit load, valve status, and actuator status, differential pressure and relative differential pressure are calculated. Combined with commissioning conditions, zero-pressure threshold, and duration, the risk state before differential pressure reverses is identified, thus proactively driving the extraction steam non-return valve to close. This shifts the timing of the auxiliary closing mechanism from after an accident occurs to the stage when the differential pressure approaches zero, suppressing malfunctions caused by pressure fluctuations, reducing the risk of medium backflow caused by mechanical reseating lag during deep peak shaving and rapid load changes, while retaining the original protection logic. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0018] Figure 1 A flowchart of an active auxiliary closing control method for turbine extraction non-return valve based on differential pressure prediction provided in an embodiment of this application; Figure 2 A schematic diagram of a turbine extraction non-return valve active auxiliary closing control device based on differential pressure prediction provided in an embodiment of this application; Figure 3 This is a schematic diagram of the active assistance control device provided in the embodiments of this application. Detailed Implementation

[0019] The purpose of this application is to provide a method for active auxiliary closing control of a turbine extraction non-return valve based on differential pressure prediction, a device for active auxiliary closing control of a turbine extraction non-return valve, an active auxiliary closing control device, and a computer-readable storage medium, so as to trigger the auxiliary closing action when the positive differential pressure still exists but has entered a state approaching zero, so as to make the extraction non-return valve move in the closing direction in advance to reduce the risk of medium backflow.

[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0021] The following embodiment illustrates the active assisted closing control method for turbine extraction non-return valve based on differential pressure prediction provided in this application.

[0022] Please refer to Figure 1 , Figure 1 The flowchart illustrates a method for active auxiliary closing control of a turbine extraction non-return valve based on differential pressure prediction, provided in an embodiment of this application.

[0023] In this embodiment, the method may include: S1 collects the extraction steam side pressure upstream of the extraction steam non-return valve, the high-pressure heater side pressure connected to the extraction steam pipeline, the unit load, the status of the extraction steam electric isolation valve, the valve position feedback of the extraction steam non-return valve, and the available signals of the auxiliary closing actuator.

[0024] This embodiment applies to the extraction steam regenerative system of an ultra-supercritical steam turbine unit. A differential pressure prediction branch is added to the existing DCS (Distributed Control System) auxiliary control logic without altering the main mechanical structure of the extraction steam non-return valve and extraction steam pipeline. The extraction steam non-return valve can be a swing-type or swing-type non-return valve equipped with a pneumatic or hydraulic auxiliary closing actuator, and has discrete valve position feedback for both fully open and fully closed positions. During the deep peak shaving phase of the unit, reaching approximately 30% of rated load, the extraction steam flow decreases, and the valve disc is prone to floating or semi-steady states. Therefore, this low-load phase is designated as a key monitoring area.

[0025] The DCS continuously receives two pressure measurement signals. The extraction steam side pressure is measured from a pressure measuring point upstream of the extraction steam non-return valve or on the extraction steam pipeline side, characterizing the pressure of steam supplied from the turbine to the high-pressure heater. The high-pressure heater side pressure is measured from a pressure measuring point on the high-pressure heater shell side or on the side where the high-pressure heater connects to the extraction steam pipeline, characterizing the pressure that may act on the downstream side of the extraction steam non-return valve from the high-pressure heater side. The two measuring points are located in the corresponding pressure regions on both sides of the extraction steam non-return valve, thus reflecting the pressure driving force of the forward flow of the medium and its changing trend.

[0026] The DCS simultaneously collects unit load, extraction steam electric isolation valve open-to-position signal, extraction steam non-return valve fully open feedback, extraction steam non-return valve fully closed feedback, and available signals from auxiliary closing actuators. For pneumatic auxiliary closing actuators, the available signal is generated by air source pressure; for hydraulic auxiliary closing actuators, the available signal is generated by hydraulic pressure or actuator readiness status. To support rapid transient condition judgment, the DCS also receives RB (Run Back, rapid load shedding) signals, rapid load reduction signals, and unit load change signals, and determines whether the load reduction rate has reached a preset threshold based on the unit load change signals. Turbine trip signals and high-high-high-high-high-high-high-high-high-high-high-high-high-low ...

[0027] S2, filter the extraction steam side pressure and the high-pressure heater side pressure, determine the difference between the filtered extraction steam side pressure and the high-pressure heater side pressure as the pressure differential, determine the larger value between the high-pressure heater side pressure and the preset low pressure lower limit as the reference pressure, and determine the relative pressure differential based on the ratio of the pressure differential to the reference pressure.

[0028] After the pressure measurement signals from the extraction steam side and the high-pressure heater side enter the DCS, they are processed using existing signal filtering or debouncing functions to reduce the impact of pressure pulsations, measurement noise, and instantaneous jumps on the judgment results. Both pressure signals use the same processing standard, and the filtering time is not set too long, thus suppressing short-term fluctuations while retaining the true pressure changes during rapid load reduction. Subsequent calculations all use the filtered or debouncing pressure values.

[0029] The extraction steam side pressure is denoted as P_ext, the high-pressure heater side pressure as P_heater, the pressure difference as ΔP, the reference pressure as P_ref, and the relative pressure difference as δ. Real-time calculations are performed according to the following relationships.

[0030] ΔP = P_ext - P_heater; P_ref=max(P_heater,P_min); δ = ΔP / P_ref.

[0031] In the formula, P_min is the preset lower pressure limit, and max represents the larger value between P_heater and P_min. P_min can be adjusted within the range of 0.5MPa to 1MPa according to the pressure measuring point range and low-pressure operating characteristics; in this embodiment, 1MPa is used. By setting P_min, the reference pressure can be prevented from being too small when the pressure on the high-pressure heater side is low, thus amplifying the measurement noise. The relative pressure difference δ is expressed as the ratio of the pressure difference ΔP to the reference pressure P_ref, so that the zero-pressure state under different extraction steam pressure levels has a unified judgment scale, avoiding excessive influence from instrument accuracy and field pressure pulsation due to direct reliance on fixed small absolute pressure differences.

[0032] When ΔP is greater than zero, the pressure on the extraction side is still higher than that on the high-pressure heater side, and the extraction branch remains in a forward steam supply pressure relationship. When ΔP remains positive while δ gradually decreases, it indicates that the pressures on both sides are approaching each other, potentially entering a risk window where the pressure difference may transition from a forward to a reverse pressure difference. Therefore, step S2 not only obtains the current pressure difference but also converts the pressure difference changes at different pressure levels into relative quantities that can be used for DCS stability comparison, providing a calculation basis for early judgment before the pressure difference reverses.

[0033] S3 generates a pre-assisted closing permission signal based on the fact that the unit load is lower than the preset commissioning load, the extraction steam electric isolation valve is in the open position, the extraction steam non-return valve is in the open position, and the auxiliary closing actuator is available.

[0034] In this embodiment, the preset operating load is set to 40% of the unit's rated load. When the actual unit load is lower than this operating load, it indicates that the unit has entered the deep peak shaving low flow range. At the same time, the DCS checks the open position signal of the extraction steam electric isolation valve. Only when the open position signal is valid is the extraction steam branch confirmed to be in an actual connected state, avoiding unnecessary pre-closing judgments on the already isolated extraction steam branch.

[0035] The opening state of the extraction non-return valve is determined jointly by two valve position feedbacks. When the fully open feedback is valid and the fully closed feedback is invalid, the DCS confirms that the extraction non-return valve is in the open state. Using a combination of fully open and fully closed feedback, instead of using only fully open feedback, can eliminate situations where valve position feedback is contradictory or unclear, ensuring that the pre-closing action only targets non-return valves that are indeed in the open state.

[0036] For the pneumatic gate-assisting actuator used in this embodiment, the DCS determines the actuator is usable when the air source pressure is not lower than 0.4 MPa, and the air source pressure can be maintained at approximately 0.6 MPa during normal operation. When the air source pressure is lower than 0.4 MPa, the pre-gate-assisting condition is not met. The control logic also retains its adaptability to hydraulic gate-assisting actuators. When a hydraulic gate-assisting actuator is configured on-site, the gate-assisting actuator is determined to be usable after the hydraulic pressure reaches the preset on-site pressure or the hydraulic gate-assisting actuator's ready signal is valid.

[0037] Based on low load, fully open extraction steam electric isolation valve, open extraction steam non-return valve, and usable auxiliary closing actuator, this embodiment further incorporates the effective use of a rapid operating condition indication signal as an additional condition for generating the pre-auxiliary closing permission signal. The rapid operating condition indication signal can be generated by the RB signal, a rapid load reduction signal, or the unit load reduction rate reaching a preset threshold; the appearance of any one of these rapid operating conditions satisfies this additional condition. Once all commissioning conditions are met simultaneously, the DCS generates the pre-auxiliary closing permission signal and opens the differential pressure approaching zero judgment channel in step S4. This combined commissioning method restricts the pre-auxiliary closing function to operating ranges with higher risks of deep peak shaving and rapid load changes, thus suppressing malfunctions caused by pressure fluctuations during normal high-load stable steam supply.

[0038] S4, during the period when the pre-assistance signal is valid, determine whether the differential pressure is greater than zero and whether the relative differential pressure is less than the preset zero-reach threshold, and generate a differential pressure approaching zero risk signal when the judgment result is continuously true for a preset holding time.

[0039] After the pre-shutdown permission signal is valid, the DCS continuously compares ΔP with zero and δ with a preset zero-reaching threshold δ_pre. δ_pre can be adjusted within the range of 0.5% to 2% based on the accuracy of the pressure measuring point, the degree of pressure fluctuation at the site, and the unit's operating experience; in this embodiment, 2% is used. Only when ΔP is greater than zero and δ is less than 2% is it determined that the extraction steam side pressure is still higher than the high-pressure heater side pressure, but the pressures on both sides have entered the risk range of approaching equilibrium. The condition that ΔP is greater than zero limits the action point to before the pressure difference reverses, distinguishing this method from control methods that only execute shutdown after backflow or reverse pressure difference is detected.

[0040] Once both comparison conditions are met simultaneously, the DCS initiates a hold timer. The preset hold time can be adjusted within the range of 0.2s to 0.5s; in this embodiment, it is set to 0.5s. During the timer, the pre-shutdown allow signal, ΔP, and δ are continuously checked. If any condition is no longer met, the hold timer resets, and no differential pressure approaching zero risk signal is generated. Only when all conditions are met continuously for 0.5s will the DCS generate a differential pressure approaching zero risk signal. The hold time can filter out short-term pulsations and instantaneous over-limits at the pressure measurement point, avoiding direct triggering of the shut-off by a single sampling fluctuation, while retaining the ability to respond to rapid differential pressure changes.

[0041] During rapid load reduction, the turbine-side extraction steam pressure typically decreases faster, while the pressure on the high-pressure heater side decreases relatively slower due to shell volume, thermal inertia, and piping system inertia. Step S4 utilizes this asynchronous pressure change characteristic to identify the continuous state of δ entering the zero-bound zone before ΔP becomes zero or negative, thereby shifting the protection judgment point forward to before the medium may backflow.

[0042] S5, in response to the risk signal that the differential pressure approaches zero, outputs a pre-closing command and controls the action of the closing actuator to drive the extraction steam non-return valve to move in the closing direction while the differential pressure is still positive.

[0043] Upon receiving a differential pressure approaching zero risk signal, the DCS immediately generates a pre-shutdown command. This pre-shutdown command does not replace the original turbine protection logic; instead, it performs an OR operation with a result-based shutdown command generated from the turbine trip signal and the high-high ...

[0044] For pneumatically assisted closing actuators, the main closing command drives the auxiliary closing solenoid valve to switch, rapidly releasing the compressed air maintaining the opening of the extraction check valve, thus releasing the pneumatic holding force. The valve core or valve disc then moves towards the valve seat under the action of spring force and gravity, completing its reseating process. For hydraulically assisted closing actuators, the main closing command controls the corresponding solenoid valve or control circuit to unload the hydraulic pressure maintaining the opening, causing the valve core or valve disc to move towards the closing direction under the action of spring force and gravity. The typical closing requirement for pneumatically assisted closing actuators is to complete closing within 1 second. Therefore, active closing can initiate the valve reseating process in advance while a positive pressure differential still exists, shortening the hysteresis window caused by relying solely on the reverse action of the medium and mechanical reseating.

[0045] Simultaneously with outputting the auxiliary closing command, the DCS starts a response timer and continuously reads the feedback from the fully closed extraction non-return valve. The preset response time is adjusted based on the designed closing time of the extraction non-return valve and the auxiliary closing actuator. In this embodiment, the response judgment is set according to the requirement that the pneumatic auxiliary closing actuator completes closing within 1 second. When the fully closed feedback becomes valid within the preset response time, the DCS records the completion of the extraction non-return valve closure and the corresponding action event, confirming the completion of the pre-assisted closing action. If the fully closed feedback is still invalid after the preset response time expires, the DCS outputs valve closing abnormality information and generates at least one of the following: alarm information, action event record, and maintenance prompt, to indicate that the extraction non-return valve may have valve disc jamming, actuator abnormality, or valve position feedback abnormality.

[0046] Through the above control process, the DCS can identify the near-zero state of the extraction steam side pressure and the high-pressure heater side pressure using the normalized relative pressure difference under deep peak shaving, low flow, and rapid load reduction conditions. It actively drives the extraction steam non-return valve to close before the reverse pressure difference forms, and confirms the action result through full-closure feedback. This method, without weakening the original protection functions such as turbine tripping and high-pressure heater water level, covers the intermediate risk window before the result-based interlock is triggered, reducing the risk of backflow caused by valve disc floating, mechanical reseating lag, or actuator malfunction.

[0047] In summary, this embodiment simultaneously collects extraction steam side pressure, high-pressure heater side pressure, unit load, valve status, and actuator status to calculate differential pressure and relative differential pressure. It then identifies the risk state before the differential pressure reverses by combining commissioning conditions, zero-point threshold, and duration, thereby proactively driving the extraction steam non-return valve to close. This shifts the timing of the auxiliary closing mechanism from after an accident occurs to the stage when the differential pressure approaches zero, suppressing malfunctions caused by pressure fluctuations, reducing the risk of medium backflow caused by mechanical reseating lag during deep peak shaving and rapid load changes, while retaining the functionality of the original protection logic.

[0048] The following describes an active auxiliary closing control device for a turbine extraction non-return valve based on differential pressure prediction, provided in an embodiment of this application. The active auxiliary closing control device for a turbine extraction non-return valve based on differential pressure prediction and the active auxiliary closing control method for a turbine extraction non-return valve based on differential pressure prediction described below can be referred to each other.

[0049] Please refer to Figure 2 , Figure 2 This is a schematic diagram of a turbine extraction non-return valve active assisted closing control device based on differential pressure prediction, provided as an embodiment of this application.

[0050] In this embodiment, the device may include: The signal acquisition module 100 is used to collect the extraction steam side pressure upstream of the extraction steam non-return valve, the high-pressure heater side pressure connected to the extraction steam pipeline, the unit load, the status of the extraction steam electric isolation valve, the valve position feedback of the extraction steam non-return valve, and the available signals of the auxiliary closing actuator. The signal processing module 200 is used to filter the extraction steam side pressure and the high-pressure heater side pressure, determine the difference between the filtered extraction steam side pressure and the high-pressure heater side pressure as the pressure difference, determine the larger value between the high-pressure heater side pressure and the preset low pressure lower limit as the reference pressure, and determine the relative pressure difference based on the ratio of the pressure difference to the reference pressure. The signal generation module 300 is used to generate a pre-assisted closing permission signal based on the fact that the unit load is lower than the preset commissioning load, the extraction steam electric isolation valve is in the open position, the extraction steam non-return valve is in the open position, and the auxiliary closing actuator is available. The zero-risk signal generation module 400 is used to determine whether the differential pressure is greater than zero and whether the relative differential pressure is less than a preset zero-reaching threshold during the effective period of the pre-assistance allow signal, and to generate a differential pressure approaching zero risk signal when the above judgment results are continuously true for a preset holding time. The control module 500 is used to output a pre-closing command in response to a risk signal that the differential pressure is approaching zero, and to control the action of the closing actuator so as to drive the extraction steam non-return valve to move in the closing direction when the differential pressure is still positive.

[0051] This application also provides an active door-assist control device; please refer to [reference needed]. Figure 3 , Figure 3 This is a schematic diagram of the active gate assist control device provided in an embodiment of this application. The active gate assist control device may include: Memory, used to store computer programs; The processor, when executing a computer program, can implement the steps of any of the above-mentioned methods for the active auxiliary closing control of the turbine extraction non-return valve based on differential pressure prediction.

[0052] like Figure 3 The diagram shows the structural composition of an active gate-assist control device. This device may include a processor 10, a memory 11, a communication interface 12, and a communication bus 13. The processor 10, memory 11, and communication interface 12 all communicate with each other via the communication bus 13.

[0053] In this embodiment, the processor 10 may be a central processing unit (CPU), an application-specific integrated circuit, a digital signal processor, a field-programmable gate array, or other programmable logic devices.

[0054] The processor 10 can call the program stored in the memory 11. Specifically, the processor 10 can execute the operations in the embodiment of the abnormal IP identification method.

[0055] The memory 11 is used to store one or more programs. The programs may include program code, which includes computer operation instructions. In this embodiment, the memory 11 stores at least a program for implementing the following functions: S1 collects the extraction steam side pressure upstream of the extraction steam non-return valve, the high-pressure heater side pressure connected to the extraction steam pipeline, the unit load, the status of the extraction steam electric isolation valve, the valve position feedback of the extraction steam non-return valve, and the available signals of the auxiliary closing actuator. S2, filter the extraction steam side pressure and the high-pressure heater side pressure, determine the difference between the filtered extraction steam side pressure and the high-pressure heater side pressure as the pressure difference, determine the larger value between the high-pressure heater side pressure and the preset low pressure lower limit as the reference pressure, and determine the relative pressure difference based on the ratio of the pressure difference to the reference pressure. S3 generates a pre-assisted closing permission signal based on the fact that the unit load is lower than the preset commissioning load, the extraction steam electric isolation valve is in the open position, the extraction steam non-return valve is in the open position, and the auxiliary closing actuator is available. S4, during the effective period of the pre-assistance signal, determine whether the differential pressure is greater than zero and whether the relative differential pressure is less than the preset zero-reach threshold, and generate a differential pressure approaching zero risk signal when the above judgment results are continuously true for a preset holding time. S5, in response to the risk signal that the differential pressure approaches zero, outputs a pre-closing command and controls the action of the closing actuator to drive the extraction steam non-return valve to move in the closing direction while the differential pressure is still positive.

[0056] In one possible implementation, the memory 11 may include a program storage area and a data storage area, wherein the program storage area may store the operating system and applications required for at least one function; and the data storage area may store data created during use.

[0057] In addition, memory 11 may include high-speed random access memory, and may also include non-volatile memory, such as at least one disk storage device or other volatile solid-state storage device.

[0058] Communication interface 12 can be an interface for the communication module, used to connect with other devices or systems.

[0059] Of course, it should be noted that, Figure 3 The structure shown does not constitute a limitation on the active gate assist control device in the embodiments of this application. In practical applications, the active gate assist control device may include devices that are more advanced than those described above. Figure 3 More or fewer components as shown, or combinations of certain components.

[0060] This application also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, can implement the steps of any of the above-described methods for active auxiliary closing control of turbine extraction non-return valve based on differential pressure prediction.

[0061] The computer-readable storage medium may include various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0062] For a description of the computer-readable storage medium provided in this application, please refer to the above method embodiments; further details will not be repeated here.

[0063] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0064] Those skilled in the art will further recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0065] The steps of the methods or algorithms described in conjunction with the embodiments disclosed herein can be implemented directly by hardware, a software module executed by a processor, or a combination of both. The software module can be located in random access memory (RAM), main memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art.

[0066] The foregoing has provided a detailed description of the active auxiliary closing control method, device, equipment, and computer-readable storage medium for a turbine extraction non-return valve based on differential pressure prediction. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the embodiments above are merely for the purpose of helping to understand the method and its core ideas. It should be noted that those skilled in the art can make various improvements and modifications to this application without departing from its principles, and these improvements and modifications also fall within the protection scope of the claims of this application.

Claims

1. A method for active auxiliary closing control of turbine extraction non-return valve based on differential pressure prediction, characterized in that, include: S1 collects the extraction steam side pressure upstream of the extraction steam non-return valve, the high-pressure heater side pressure connected to the extraction steam pipeline, the unit load, the status of the extraction steam electric isolation valve, the valve position feedback of the extraction steam non-return valve, and the available signals of the auxiliary closing actuator. S2, the extraction steam side pressure and the high-pressure heater side pressure are filtered, the difference between the filtered extraction steam side pressure and the high-pressure heater side pressure is determined as the pressure difference, the larger value between the high-pressure heater side pressure and the preset low pressure lower limit is determined as the reference pressure, and the relative pressure difference is determined according to the ratio of the pressure difference to the reference pressure. S3, based on the fact that the unit load is lower than the preset operating load, the extraction steam electric isolation valve is in the open position, the extraction steam non-return valve is in the open position, and the auxiliary closing actuator is available, a pre-auxiliary closing permission signal is generated; S4, during the effective period of the pre-assistance allow signal, determine whether the pressure difference is greater than zero and whether the relative pressure difference is less than a preset zero-reaching threshold, and generate a pressure difference zero-reaching risk signal when the above determination results are continuously true for a preset holding time. S5, in response to the risk signal that the differential pressure approaches zero, outputs a pre-assisted closing command and controls the closing actuator to move so as to drive the extraction steam non-return valve to move in the closing direction when the differential pressure is still positive.

2. The active auxiliary closing control method for the turbine extraction non-return valve according to claim 1, characterized in that, In step S1, the extraction steam side pressure is taken from the pressure measuring point upstream of the extraction steam non-return valve or on the extraction steam pipeline side, and the high-pressure heater side pressure is taken from the pressure measuring point on the high-pressure heater shell side or on the side where the high-pressure heater is connected to the extraction steam pipeline; in step S2, the extraction steam side pressure and the high-pressure heater side pressure are filtered or de-jittered using a distributed control system, and the pressure difference and the relative pressure difference are calculated using the processed pressure values.

3. The active auxiliary closing control method for the steam turbine extraction non-return valve according to claim 2, characterized in that, Let the extraction steam side pressure be denoted as P_ext, the high-pressure heater side pressure as P_heater, the pressure difference as ΔP, the reference pressure as P_ref, and the relative pressure difference as δ, then: ΔP = P_ext - P_heater; P_ref=max(P_heater,P_min); δ = ΔP / P_ref; Wherein, P_min is the preset low-pressure lower limit, with a value of 0.5MPa to 1MPa; the preset zero-reach threshold is 0.5% to 2%; and the preset holding time is 0.2s to 0.5s.

4. The active auxiliary closing control method for the turbine extraction non-return valve according to claim 1, characterized in that, In step S3, the preset operating load is 40% of the unit's rated load; the extraction non-return valve is determined to be in the open state based on the effective feedback of the fully open valve and the ineffective feedback of the fully closed valve; when the auxiliary closing actuator is a pneumatic auxiliary closing actuator, the auxiliary closing actuator is determined to be usable based on the air source pressure not being lower than 0.4 MPa; when the auxiliary closing actuator is a hydraulic auxiliary closing actuator, the auxiliary closing actuator is determined to be usable based on the hydraulic pressure reaching the preset pressure or the hydraulic auxiliary closing actuator's ready signal being effective.

5. The active auxiliary closing control method for the turbine extraction non-return valve according to claim 4, characterized in that, S3 further includes: acquiring a rapid operating condition indication signal and using the rapid operating condition indication signal as an additional condition for generating the pre-shutdown permission signal; wherein the rapid operating condition indication signal includes at least one of an RB signal, a rapid load reduction signal, and a signal generated when the unit load reduction rate reaches a preset rate threshold.

6. The active auxiliary closing control method for the turbine extraction non-return valve according to claim 1, characterized in that, S5 includes: performing an OR logic operation on the pre-assisted closing command and the resulting assisted closing command generated based on the turbine trip signal and / or the high-high water level signal of the high-pressure heater to generate a general assisted closing command; controlling the switching of the assisted closing solenoid valve according to the general assisted closing command to quickly release the pneumatic pressure maintaining the opening of the extraction steam non-return valve, or to unload the hydraulic pressure maintaining the opening of the extraction steam non-return valve, so that the extraction steam non-return valve moves towards the valve seat under the action of spring force and / or gravity.

7. The active auxiliary closing control method for the turbine extraction non-return valve according to claim 6, characterized in that, After outputting the auxiliary closing command, a response timer is started, and feedback on the full closure of the extraction non-return valve is obtained. When a valid full closure feedback is obtained within the preset response time, the closure of the extraction non-return valve is recorded. When a valid full closure feedback is not obtained within the preset response time, valve closure abnormality information is output. The valve closure abnormality information includes at least one of alarm information, action event record, and maintenance prompt.

8. A turbine extraction non-return valve active assisted closing control device based on differential pressure prediction, characterized in that, include: The signal acquisition module is used to collect the extraction steam side pressure upstream of the extraction steam non-return valve, the high-pressure heater side pressure connected to the extraction steam pipeline, the unit load, the status of the extraction steam electric isolation valve, the valve position feedback of the extraction steam non-return valve, and the available signals of the auxiliary closing actuator. The signal processing module is used to filter the extraction steam side pressure and the high-pressure heater side pressure, determine the difference between the filtered extraction steam side pressure and the high-pressure heater side pressure as the pressure difference, determine the larger value between the high-pressure heater side pressure and the preset low pressure lower limit as the reference pressure, and determine the relative pressure difference based on the ratio of the pressure difference to the reference pressure. The signal generation module is used to generate a pre-assisted closing permission signal based on the following conditions: the unit load is lower than the preset commissioning load, the extraction steam electric isolation valve is in the fully open state, the extraction steam non-return valve is in the open state, and the auxiliary closing actuator is available. The zero-risk signal generation module is used to determine whether the differential pressure is greater than zero and whether the relative differential pressure is less than a preset zero-approach threshold during the effective period of the pre-assistance allow signal, and generate a differential pressure approach-zero risk signal when the above determination results are continuously true for a preset holding time. The control module is used to output a pre-closing command in response to the differential pressure approaching zero risk signal, and control the closing actuator to drive the extraction steam non-return valve to move in the closing direction when the differential pressure is still positive.

9. An active assistance control device, characterized in that, include: Memory, used to store computer programs; A processor, configured to execute the computer program to implement the steps of the active auxiliary closing control method for the steam turbine extraction non-return valve as described in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, implements the steps of the active auxiliary closing control method for the steam turbine extraction non-return valve as described in any one of claims 1 to 7.

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