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CN-122016182-A - Online detection and positioning method and device for air leakage of pneumatic actuator

CN122016182ACN 122016182 ACN122016182 ACN 122016182ACN-122016182-A

Abstract

The invention provides an on-line detection and positioning method and device for air leakage of a pneumatic actuating mechanism, comprising the steps of deploying high-temperature-resistant acoustic sensors at an air source inlet, an air cylinder sealing surface and a stuffing box, installing miniature pressure and flow sensors on an air source pipeline, transmitting data to an edge terminal through a shielding cable, collecting environmental noise in a mechanism standby state, generating a baseline spectrogram, setting a dynamic noise threshold value, synchronously collecting multi-source signals in an actuating mechanism action period, carrying out band-pass filtering on acoustic signals, eliminating environmental interference, carrying out smoothing treatment on pressure and flow signals, judging air leakage and classifying by combining the characteristics of the amplitude exceeding threshold value, the pressure drop rate and the flow mutation of the acoustic signals, and realizing accurate positioning of leakage points by utilizing the arrival time difference of the multi-point acoustic signals and the pressure/flow characteristic points. The method can realize online accurate identification and positioning of the leakage points, and is suitable for the field environment with high temperature, high humidity and strong noise.

Inventors

  • XU CHAOFAN

Assignees

  • 华能太仓发电有限责任公司

Dates

Publication Date
20260512
Application Date
20260203

Claims (10)

  1. 1. The method for detecting and positioning the air leakage of the pneumatic actuator on line is characterized by comprising the following steps of: S1, deploying a multi-source sensor system, installing a high-temperature-resistant acoustic sensor at the positions of an air source inlet pipe section, an air cylinder end cover sealing surface and a piston rod stuffing box of a pneumatic actuating mechanism, installing a miniature pressure sensor and a flow sensor at the position, close to the actuating mechanism, of an air source pipeline, and transmitting sensor data to an edge computing terminal through an anti-electromagnetic interference shielding cable; S2, establishing an environmental noise baseline, controlling the pneumatic actuator to be in a non-action standby state, collecting environmental noise signals, performing spectrum analysis, generating an environmental noise baseline spectrogram, and setting a dynamic noise threshold value based on the baseline spectrogram; S3, acquiring a dynamic air leakage signal, performing multidimensional filtering treatment, controlling a pneumatic executing mechanism to synchronously acquire an acoustic wave signal, a pressure signal and a flow signal when a complete action cycle is completed, performing band-pass filtering on the acoustic wave signal, removing an interference signal by combining an environmental noise baseline spectrogram, and performing smoothing treatment on the pressure signal and the flow signal to eliminate instantaneous fluctuation; S4, carrying out air leakage identification and leakage point positioning based on multi-source signal characteristics, judging that air leakage exists and classifying leakage rate grades by comparing the amplitude of a target sound wave signal with a dynamic noise threshold value and analyzing the pressure drop rate of a pressure signal in an action stagnation stage and the abrupt change characteristics of a flow signal, and determining the position of the leakage point by combining the signal arrival time difference of acoustic sensors at different positions and the pressure flow curve characteristic points.
  2. 2. The method of claim 1, wherein S1 comprises: s11, the working temperature range of a high-temperature-resistant acoustic sensor arranged at the air source inlet pipe section, the sealing surface of the air cylinder end cover and the stuffing box of the piston rod is-20 ℃ to 80 ℃; s12, the electromagnetic interference resistance level of the passing shielding cable is more than or equal to EMCEN 61000-6-2 standard.
  3. 3. The method of claim 1, wherein S2 comprises: s21, continuously acquiring an environmental noise signal for 30S through an acoustic sensor when the pneumatic actuator is controlled to be in a non-action standby state, wherein the acquisition time window is 30S long and the sampling frequency is 44.1kHz; S22, extracting frequency distribution characteristics of the noise signals through Fourier transformation, wherein the frequency distribution characteristics are mainly concentrated in a 50-2000Hz frequency band, and setting a dynamic noise threshold value based on the maximum amplitude of a baseline spectrogram multiplied by 1.2.
  4. 4. The method of claim 1, wherein S3 further comprises: s31, when the acoustic wave signal is subjected to band-pass filtering treatment, a filter with a passband frequency range of 2000-20000Hz is adopted, and the passband frequency range avoids the main frequency band of 50-2000Hz of environmental noise; s32, when the pressure signal and the flow signal are subjected to smoothing processing, a moving average algorithm is adopted, wherein the window size of the moving average algorithm is 5 sampling points, and the sampling interval is 10ms.
  5. 5. The method of claim 1, wherein S4 comprises: S41, when the existence of air leakage is judged, the amplitude of a target sound wave signal S is required to be continuously more than or equal to 2 times of a noise threshold T, the pressure drop rate of a pressure curve P (T) in an action stagnation stage is more than or equal to 0.5kPa/min, and the numerical value of a flow curve Q (T) in the stage is more than or equal to 3L/min; S42, when the leak rate grade is divided, slight air leakage is defined as Q <5L/min, moderate air leakage is defined as Q <15L/min and serious air leakage is defined as Q < 15L/min.
  6. 6. The utility model provides a pneumatic actuator gas leakage on-line measuring and positioner which characterized in that includes: The sensor deployment module is used for installing a high-temperature-resistant acoustic sensor at the air source inlet pipe section, the air cylinder end cover sealing surface and the piston rod stuffing box of the pneumatic actuating mechanism, installing a miniature pressure sensor and a flow sensor at the position of the air source pipeline close to the actuating mechanism, and transmitting sensor data to the edge computing terminal through an anti-electromagnetic interference shielding cable; The system comprises an environmental noise baseline establishing module, a dynamic noise threshold value setting module and a dynamic noise threshold value setting module, wherein the environmental noise baseline establishing module is used for controlling the pneumatic executing mechanism to be in a non-action standby state, collecting environmental noise signals and performing frequency spectrum analysis to generate an environmental noise baseline spectrogram, and setting the dynamic noise threshold value based on the baseline spectrogram; The dynamic air leakage signal acquisition and filtering module is used for controlling the pneumatic actuating mechanism to synchronously acquire an acoustic wave signal, a pressure signal and a flow signal when the pneumatic actuating mechanism completes a complete action cycle, carrying out band-pass filtering on the acoustic wave signal, eliminating an interference signal by combining an environmental noise baseline spectrogram, and carrying out smoothing treatment on the pressure signal and the flow signal so as to eliminate instantaneous fluctuation; and the air leakage identification and positioning module is used for judging the existence of air leakage and dividing the leakage rate level by comparing the amplitude of the target sound wave signal with a dynamic noise threshold value and analyzing the pressure drop rate of the pressure signal in the action stagnation stage and the abrupt change characteristics of the flow signal, and determining the position of the leakage point by combining the signal arrival time difference of the acoustic sensors at different positions and the pressure flow curve characteristic points.
  7. 7. The apparatus of claim 6, wherein the ambient noise baseline establishing module is further to: When the pneumatic actuator is controlled to be in a non-action standby state, continuously acquiring an environmental noise signal for 30s through the acoustic sensor, wherein the acquisition time window is 30s long and the sampling frequency is 44.1kHz; And extracting frequency distribution characteristics of the noise signals through Fourier transformation, wherein the frequency distribution characteristics are mainly concentrated in a frequency band of 50-2000Hz, and setting a dynamic noise threshold value based on 1.2 times of the maximum amplitude of the baseline spectrogram.
  8. 8. The apparatus of claim 6, wherein the dynamic air leakage signal acquisition and filtering module is further configured to: When the acoustic wave signal is subjected to band-pass filtering treatment, a filter with a pass band frequency range of 2000-20000Hz is adopted, and the pass band frequency range avoids the main frequency band of 50-2000Hz of environmental noise; when the pressure signal and the flow signal are subjected to smoothing processing, a moving average algorithm is adopted, wherein the window size of the moving average algorithm is 5 sampling points, and the sampling interval is 10ms.
  9. 9. A computer device comprising a processor and a memory; Wherein the processor runs a program corresponding to the executable program code by reading the executable program code stored in the memory, for implementing the pneumatic actuator air leakage on-line detection and positioning method as claimed in any one of claims 1 to 5.
  10. 10. A non-transitory computer readable storage medium having stored thereon a computer program, wherein the program when executed by a processor implements the pneumatic actuator leak on-line detection and localization method of any one of claims 1-5.

Description

Online detection and positioning method and device for air leakage of pneumatic actuator Technical Field The invention belongs to the technical field of detection, and particularly relates to an online detection and positioning method and device for air leakage of a pneumatic actuator. Background The pneumatic actuating mechanism is a key control component in a steam turbine room of a thermal power plant, is widely used for core operations such as valve opening and closing, baffle plate adjustment and the like, and the running reliability of the pneumatic actuating mechanism directly influences the safety and stability and the energy consumption level of a unit. The existing leakage detection technology has obvious defects that 1, manual inspection depends on a soapy water smearing method, the efficiency is low (single detection takes more than 15 minutes), the subjectivity is high, tiny leakage points are difficult to find (the leakage rate is less than 5 mL/min), 2, the traditional ultrasonic detector is interfered by steam flow noise and equipment vibration noise in the steam turbine room, the signal to noise ratio is low, the false alarm rate is more than 30%, 3, the pressure drop detection method needs to pause the operation of an executing mechanism, the operation requirements of 'no stop and less stop' of a thermal power plant can not be met, and the leakage point position can not be positioned. The problem causes that the air leakage fault of the pneumatic actuating mechanism is not found timely, compressed air is wasted, valve blocking and adjustment precision reduction can be caused, and when the air leakage fault is severe, the unit is subjected to load reduction or unplanned shutdown, so that an air leakage detection method which is suitable for a complex environment of a steam turbine room, efficient and accurate and can be operated on line is needed. Disclosure of Invention The present invention aims to solve at least one of the technical problems in the related art to some extent. Therefore, a first object of the present invention is to provide an online detection and positioning method for air leakage of a pneumatic actuator. The invention aims to overcome the defects of the prior art in the environment of a steam turbine room of a thermal power plant, and provides a method for detecting the air leakage of a pneumatic actuator of the steam turbine room of the thermal power plant, which realizes the online accurate identification and positioning of leakage points and is suitable for the field environment with high temperature, high humidity and strong noise. The second objective of the present invention is to provide an air leakage on-line detecting and positioning device for a pneumatic actuator. A third object of the invention is to propose a computer device. A fourth object of the present invention is to propose a non-transitory computer readable storage medium. To achieve the above objective, an embodiment of a first aspect of the present invention provides an online detection and positioning method for air leakage of a pneumatic actuator, including: S1, deploying a multi-source sensor system, installing a high-temperature-resistant acoustic sensor at the positions of an air source inlet pipe section, an air cylinder end cover sealing surface and a piston rod stuffing box of a pneumatic actuating mechanism, installing a miniature pressure sensor and a flow sensor at the position, close to the actuating mechanism, of an air source pipeline, and transmitting sensor data to an edge computing terminal through an anti-electromagnetic interference shielding cable; S2, establishing an environmental noise baseline, controlling the pneumatic actuator to be in a non-action standby state, collecting environmental noise signals, performing spectrum analysis, generating an environmental noise baseline spectrogram, and setting a dynamic noise threshold value based on the baseline spectrogram; S3, acquiring a dynamic air leakage signal, performing multidimensional filtering treatment, controlling a pneumatic executing mechanism to synchronously acquire an acoustic wave signal, a pressure signal and a flow signal when a complete action cycle is completed, performing band-pass filtering on the acoustic wave signal, removing an interference signal by combining an environmental noise baseline spectrogram, and performing smoothing treatment on the pressure signal and the flow signal to eliminate instantaneous fluctuation; S4, carrying out air leakage identification and leakage point positioning based on multi-source signal characteristics, judging that air leakage exists and classifying leakage rate grades by comparing the amplitude of a target sound wave signal with a dynamic noise threshold value and analyzing the pressure drop rate of a pressure signal in an action stagnation stage and the abrupt change characteristics of a flow signal, and determining the position of the leakage point by combining the si