Method for detecting water leakage of a top cover of a hydraulic turbine unit

Abstract

A kind of detection method suitable for water turbine set top cover water leakage, steps are as follows: the voiceprint signal of top cover is collected, the voiceprint signal includes metal medium propagation voiceprint signal, air propagation voiceprint signal and liquid medium propagation voiceprint signal;Filter metal medium propagation voiceprint signal: according to the speed of sound propagation in different medium, the corresponding voiceprint phase displacement of different medium is obtained, the metal medium propagation voiceprint signal is screened out by the size of voiceprint phase displacement, and the metal medium propagation voiceprint signal is rejected;Whether top cover is judged to leak: after rejecting metal medium propagation voiceprint signal, continue to judge the remaining voiceprint signal according to voiceprint phase displacement, if the remaining voiceprint signal is only air propagation voiceprint signal, then it proves that top cover does not leak;If voiceprint signal also includes liquid medium propagation voiceprint signal, then it proves that top cover has water leakage accident.The present application can overcome the shortcomings of traditional monitoring method, and reduce the interference of water level fluctuation.

Description

Technical Field

[0001] This invention belongs to the technical field of water leakage inspection of turbine generator top cover, and specifically relates to a detection method suitable for water leakage of turbine generator top cover. Background Technology

[0002] The top cover is one of the most important components of a hydro turbine, requiring sufficient strength and rigidity. Its functions include: forming a flow channel together with the bottom ring; preventing water overflow; supporting the guide vanes, transmission mechanism, guide vane bearings, and other auxiliary devices. The top cover drainage system is an essential auxiliary system for hydro-generator units. Regardless of whether the unit is generating or shut down, water accumulation in the top cover is mainly caused by leakage from the guide vane bushing and leakage between the top cover and the main shaft. The top cover drainage pump, as the core of the top cover drainage system, drains leaked water, preventing excessive water accumulation from flooding the guide vane bearings and causing unplanned unit shutdowns.

[0003] Turbine top cover drainage generally employs two methods: fixed guide vane gravity drainage or forced drainage using a top cover pump. The forced drainage system mainly consists of three parts: a drainage pump, a water level monitoring system, and a top cover pump start / stop logic control loop. Top cover water level monitoring is performed by water level sensors and water level signalers. The water level sensors output analog signals to the monitoring system for real-time monitoring and alarm functions. The on / off terminals of the water level signaler are used to control the start and stop of the top cover pump, achieving the purpose of pumping out accumulated water from the top cover.

[0004] The current method of using a water level switch to detect whether the top cover is leaking has the following shortcomings:

[0005] 1. Water level fluctuation: When the water level is near the level of the analog pump start / stop, the fluctuation of the water level in the reservoir causes the water level switch to malfunction.

[0006] 2. Due to the different installation locations of each water pump, when the sensor installation location or the water inlet of the reservoir is far from a certain water pump, the actual water level near the water pump is lower than the value measured by the sensor when the water pump is pumping water. This causes the actual water level near the water pump to exceed the analog pump stop water level of the water level sensor when the water pump stops, resulting in the false activation of the pump stop water level switch near the water pump.

[0007] 3. Sudden changes in water flow: If the water flow suddenly increases and the water level rises rapidly, during the process of the pump reaching the analog start-up water level - program judgment - issuing command - pump start - pipeline filling, the water level may rise to the vicinity of the start-up water level switch in a short period of time, causing the start-up water level switch to malfunction.

[0008] 4. The water level difference between the analog start / stop setting value and the digital start / stop setting value is generally set to be small. Simply increasing the distance between the analog and digital quantities to prevent the switch from malfunctioning may not meet the system water level control requirements.

[0009] 5. If the water level switch keeps reverting to abnormal operation or the water level sensor gets stuck in a certain position, it will cause the dynamic start-stop pump water level update frequency to be too high, causing the dynamic control function of the water pump start-stop water level to enter an abnormal state.

[0010] 6. If the water level switch is stuck in the highest position, the pump will not stop even if the water level drops to the stop position after the top cover pump is started, which will cause the motor to burn out due to idling; if the water level switch is stuck in the lowest position, the entire top cover drainage system will lose its drainage capacity, resulting in excessive water accumulation and flooding of the water guide bearing, which will cause the unit to shut down unplanned.

[0011] 7. The turbine top cover is in a long-term humid and complex environment where oil and water pollutants are mixed together. Due to long-term chemical changes, the float of the water level switch becomes stuck due to sticky pollutants, which is difficult to avoid.

[0012] 8. Due to the installation of the turbine top cover or long-term environmental factors causing blockage of the connecting holes between the various sub-reservoirs, the water level in the top cover becomes unbalanced. As a result, the water in the top cover where the top cover pump is installed has been pumped out, but the water in the top covers of other sub-reservoirs where the top cover pump is not actually installed has not been pumped out. There is still water accumulation on the working surface of the top cover, which affects safety.

[0013] Therefore, using voiceprint detection technology to detect leaks in the top cover is a feasible approach that can address the shortcomings of water level switches. Summary of the Invention

[0014] In view of the technical problems existing in the background art, the detection method for water leakage of the top cover of the turbine unit provided by the present invention utilizes the characteristics of sound wave signals and the waveform changes of sound waves in different media to determine whether the top cover is leaking. Compared with the traditional water level gauge technology for detecting water leakage of the top cover, the present invention can overcome the shortcomings of the traditional monitoring method and reduce the interference of water level fluctuations.

[0015] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0016] A method for detecting water leakage in the top cover of a hydroelectric turbine unit, comprising the following steps:

[0017] Step 1: Collect the acoustic signature signal of the top cover. The acoustic signature signal includes acoustic signature signal propagated through metal medium, acoustic signature signal propagated through air, and acoustic signature signal propagated through liquid medium.

[0018] Step 2, Filtering the acoustic signature signal propagated through the metal medium: Based on the speed of sound propagation in different media, the corresponding acoustic signature phase displacement for different media is obtained. The acoustic signature signal propagated through the metal medium is filtered out by the magnitude of the acoustic signature phase displacement.

[0019] Step 3: Determine if the top cover is leaking: After eliminating the acoustic signal transmitted through the metal medium, continue to judge the remaining acoustic signal based on the phase displacement of the acoustic signal. If the remaining acoustic signal is only the acoustic signal transmitted through the air, it proves that the top cover is not leaking; if the acoustic signal also includes the acoustic signal transmitted through the liquid medium, it proves that the top cover has leaked.

[0020] Preferably, in step 1, multiple sets of voiceprint acquisition arrays are set on the top cover, with at least four sets of voiceprint acquisition arrays distributed in four directions on the top cover. Each set of voiceprint acquisition arrays includes at least three voiceprint collectors. The three voiceprint collectors in each set of voiceprint acquisition arrays are SC1, SC2, and SC3, respectively. SC1, SC2, and SC3 are installed on the same vertical line from bottom to top, with a distance of d1 meters between them.

[0021] The sources of acoustic signals propagating through metallic media are: acoustic signals caused by vibrations during the operation of the turbine unit and acoustic signals caused by vibrations of the roof due to ambient sound waves;

[0022] The source of the airborne acoustic signature signal is: acoustic wave signal caused by environmental vibration of the hydroelectric power plant;

[0023] Acoustic signal propagation through liquid medium: the acoustic signal after the acoustic sensor is submerged.

[0024] Preferably, in step 2, the calculation process for the acoustic signature phase displacement is as follows:

[0025] The relationship between the frequency, wavelength, and velocity of sound waves propagating in different media is as follows:

[0026] u=λ*ν;

[0027] u represents wave speed, λ represents wavelength, and ν represents frequency;

[0028] The signals propagating through the metallic medium acquired by each acoustic signature acquisition array will all undergo corresponding acoustic signature phase shifts due to different distances. These acoustic signature phase shifts satisfy the following:

[0029] Let any acoustic fingerprint sensor be the origin O, then the vibration at that point is: ;

[0030] Where A is the amplitude. Angular frequency, The initial phase is given by t, which represents time. Indicates displacement; where A, , It is a fixed value;

[0031] The vibration at point P of the other voiceprint collector in this group is: ;

[0032] In the formula, assuming point O is SC1 and point P is the position of SC2, x is equivalent to the distance d1 between SC1 and SC2. If point P is SC3, x is equivalent to the distance 2d1 between SC3 and SC1.

[0033] Assume point O is SC2 and point P is SC1. x is equivalent to the distance between SC2 and SC1 - d1. If point P is SC3, x is equivalent to the distance between SC3 and SC2 d1.

[0034] Assume point 0 is SC3 and point P is SC1. x is equivalent to the distance between SC3 and SC1, which is -2d1. If point P is SC2, x is equivalent to the distance between SC2 and SC3, which is -d1.

[0035] x can be understood as the distance between the voiceprint collectors can be set arbitrarily, meaning that the voiceprint collectors can be arranged arbitrarily in a straight line, as long as the distance between them and a positive direction are known.

[0036] because = u= ;

[0037] Therefore, the vibration wave function at point P is: ;

[0038] Therefore, by analyzing the phase shift of the acoustic signatures from the two acoustic signature collectors using spectral analysis, it is determined whether to filter out acoustic signature signals propagating through metallic media, for the same frequency. The sound wave judgment conditions are as follows:

[0039] 1) u 钢铁 At a speed of 5000 m / s, a phase displacement of... ;

[0040] 2) u 水 It is 1500 meters per second. ;

[0041] 3) u 空气 It is 340 meters per second. ;

[0042] Compare the sound source signals of the two voiceprint collectors. The one with the smallest phase difference is the sound wave propagated through the metal medium. Filter out the voiceprint signal propagated through the metal medium.

[0043] Preferably, when it is determined that the top cover is leaking, the following further steps are taken:

[0044] Step 4, the start-up and shutdown conditions for the main top cover pump and the standby top cover pump are as follows:

[0045] 1) When all SC2 in the 4 sets of acoustic fingerprint acquisition arrays are submerged, it indicates a small amount of water leakage. The main top cover pump is started. When none of the SC2 in the 4 sets of acoustic fingerprint acquisition arrays are submerged, the main top cover pump is stopped.

[0046] 2) If any SC3 of any 3 sets of acoustic fingerprint collectors is submerged, it indicates a large amount of water leakage, and a high water level alarm signal is given for the top cover, and a command to start the backup top cover pump is given; if the submerged signal of the SC3 of any 3 sets of acoustic fingerprint collectors disappears, a command to stop the backup top cover pump is given.

[0047] Preferably, after step 4 is completed, the pump stop time T1 and start time T2 of the main top cover pump are compared, and the leakage amount is calculated linearly.

[0048] Step 5, using the formula = By comparing the amount of leakage, an early warning can be issued:

[0049] In the formula, T1-T2 represents the drainage time, and d1 is the elevation difference of the acoustic fingerprint collector installation.

[0050] Since the drainage capacity of the top cover pump is fixed, then when Right now A large number indicates a large leakage. The larger the value, the greater the leakage. The smaller the value, the smaller the leakage.

[0051] Preferably, after step 5 is completed, the drainage capacity is determined:

[0052] Step 6, the nth group of events - =

[0053] The (n+1)th group of events - = ;

[0054] when < At that time, the surface of the top cover was not draining enough.

[0055] Conversely, it indicates that the current drainage capacity of the roof is sufficient.

[0056] A detection system and method for detecting water leakage in the top cover of a hydroelectric turbine unit, comprising a voiceprint collector, a voiceprint storage module, a voiceprint extraction module, a waveform calculation module, a logic calculation module, and a signal output module; multiple voiceprint collectors constitute a voiceprint acquisition array, and the geographical location information of the voiceprint acquisition array serves as an input to the waveform calculation module, which then performs... Waveforms from t minutes ago and real-time The waveform calculation at a given time becomes the input to the logic calculation module; the judgment result after logic calculation becomes the input to the signal output module; the signal output module is used to link with the main top cover pump and the standby top cover pump.

[0057] The present invention can achieve the following beneficial effects:

[0058] 1. By utilizing the characteristics of sound wave signals and the waveform changes of sound waves in different media, this invention can determine whether the top cover is leaking. Compared with the traditional water level gauge technology for detecting leaks in the top cover, this invention can overcome the shortcomings of traditional monitoring methods and reduce the interference of water level fluctuations.

[0059] 2. By comparing the changes in the phase displacement of acoustic waves from different known locations of acoustic fingerprint collectors, the amount of subsequent calculation and processing can be simplified;

[0060] 3. To resolve issues such as abnormal reactivation or jamming of the water level switch, eliminating the possibility of motor burnout or water accumulation leading to flooding of the water guide bearing. Attached Figure Description

[0061] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0062] Figure 1 This is a diagram showing the orientation of the voiceprint acquisition array of the present invention.

[0063] Figure 2 This is a diagram showing the arrangement of the voiceprint collectors in the single-group voiceprint acquisition array of the present invention;

[0064] Figure 3 A logic diagram for determining whether the top cover of this invention leaks water;

[0065] Figure 4 This is the start / stop logic diagram of the top cover pump of the present invention;

[0066] Figure 5 This invention provides the logic for determining the size of water leakage from the top cover.

[0067] Figure 6 This is a logic diagram of the drainage capacity of the present invention;

[0068] Figure 7 This invention provides the logic for determining blockage in the connecting valve.

[0069] Figure 8 This is a structural diagram of a detection system for water leakage in the top cover of a water turbine unit according to the present invention. Detailed Implementation

[0070] Example 1:

[0071] Preferred solutions include Figures 1 to 6 As shown, a method for detecting water leakage in the top cover of a hydroelectric turbine unit includes the following steps:

[0072] Step 1: Collect the acoustic signature signal of the top cover. The acoustic signature signal includes acoustic signature signal propagated through metal medium, acoustic signature signal propagated through air, and acoustic signature signal propagated through liquid medium.

[0073] Step 2, Filtering the acoustic signature signal propagated through the metal medium: Based on the speed of sound propagation in different media, the corresponding acoustic signature phase displacement for different media is obtained. The acoustic signature signal propagated through the metal medium is filtered out by the magnitude of the acoustic signature phase displacement.

[0074] Step 3: Determine if the top cover is leaking: After eliminating the acoustic signal transmitted through the metal medium, continue to judge the remaining acoustic signal based on the phase displacement of the acoustic signal. If the remaining acoustic signal is only the acoustic signal transmitted through the air, it proves that the top cover is not leaking; if the acoustic signal also includes the acoustic signal transmitted through the liquid medium, it proves that the top cover has leaked.

[0075] Furthermore, in step 1, multiple sets of voiceprint acquisition arrays are set on the top cover, with at least four sets of voiceprint acquisition arrays distributed in four directions on the top cover. Each set of voiceprint acquisition arrays includes at least three voiceprint collectors. The four sets of voiceprint acquisition arrays are arranged in the following directions: X-left, X-right, Y-up, and Y-down, where X represents the X-axis and Y represents the Y-axis. The three voiceprint collectors are SC1, SC2, and SC3, respectively.

[0076] The sources of acoustic signals propagating through metallic media are: acoustic signals caused by vibrations during the operation of the turbine unit and acoustic signals caused by vibrations of the roof due to ambient sound waves;

[0077] The source of the airborne acoustic signature signal is: acoustic wave signal caused by environmental vibration of the hydroelectric power plant;

[0078] Acoustic signal propagation through liquid (water or oil-water mixture): the acoustic signal after the acoustic sensor is immersed.

[0079] Furthermore, in step 2, the calculation process for the acoustic signature phase displacement is as follows:

[0080] The relationship between the frequency, wavelength, and velocity of sound waves propagating in different media is as follows:

[0081] u=λ*ν;

[0082] u represents wave speed, λ represents wavelength, and ν represents frequency;

[0083] The signals propagating through the metallic medium acquired by each acoustic signature acquisition array will all undergo corresponding acoustic signature phase shifts due to different distances. These acoustic signature phase shifts satisfy the following:

[0084] Let any acoustic fingerprint sensor (e.g., SC1) be the origin O. Then the vibration at that point is: ;

[0085] Where A is the amplitude. Angular frequency, The initial phase is given by t, which represents time. Indicates displacement; where A, , It is a fixed value;

[0086] The vibration at point P of another voiceprint collector in this group (e.g., SC2) is: ;

[0087] In the formula, assuming point O is SC1 and point P is the position of SC2, x is equivalent to the distance d1 between SC1 and SC2. If point P is SC3, x is equivalent to the distance 2d1 between SC3 and SC1.

[0088] Assume point O is SC2 and point P is SC1. x is equivalent to the distance between SC2 and SC1 - d1. If point P is SC3, x is equivalent to the distance between SC3 and SC2 d1.

[0089] Assume point 0 is SC3 and point P is SC1. x is equivalent to the distance between SC3 and SC1, which is -2d1. If point P is SC2, x is equivalent to the distance between SC2 and SC3, which is -d1.

[0090] x can be understood as the distance between the voiceprint collectors can be set arbitrarily, meaning that the voiceprint collectors can be arranged arbitrarily in a straight line, as long as the distance between them and a positive direction are known.

[0091] because = u= ;

[0092] Therefore, the vibration wave function at point P is: ;

[0093] Therefore, by analyzing the phase shift of the acoustic signatures from the two acoustic signature collectors using spectral analysis, it is determined whether to filter out acoustic signature signals propagating through metallic media, for the same frequency. The sound wave judgment conditions are as follows:

[0094] 1) u 钢铁 At a speed of 5000 m / s, a phase displacement of... ;

[0095] 2) u 水 It is 1500 meters per second. ;

[0096] 3) u空气 It is 340 meters per second. ;

[0097] Compare the sound source signals of the two voiceprint collectors. The one with the smallest phase difference is the sound wave propagated through the metal medium. Filter out the voiceprint signal propagated through the metal medium.

[0098] After filtering out the acoustic signatures propagating through metal, the acoustic signature collector only collects acoustic signatures propagating through air and liquid. The determination of whether the acoustic signature collector is submerged: If the acoustic signature collector SC1 is not submerged, the sound wave signal it collects will only contain acoustic signatures propagating through air. That is, as long as the phase of the sound wave does not change with the previously recorded sound wave, the acoustic signature collector is considered not submerged; if a phase change occurs, it is considered submerged. At this time, the control module issues a top cover leakage signal.

[0099] Furthermore, if it is determined that the top cover is leaking, the following steps should be taken:

[0100] Step 4: The three voiceprint collectors in each voiceprint acquisition array are SC1, SC2, and SC3; SC1, SC2, and SC3 are installed on the same vertical line from bottom to top, with a distance of d1 meters between each; the judgment conditions are as follows:

[0101] 1) When all SC2 in the 4 sets of acoustic fingerprint acquisition arrays are submerged, it indicates a small amount of water leakage. The main top cover pump is started. When none of the SC2 in the 4 sets of acoustic fingerprint acquisition arrays are submerged, the main top cover pump is stopped.

[0102] 2) If any SC3 of any 3 sets of acoustic fingerprint collectors is submerged, it indicates a large amount of water leakage, and a high water level alarm signal is given for the top cover, and a command to start the backup top cover pump is given; if the submerged signal of the SC3 of any 3 sets of acoustic fingerprint collectors disappears, a command to stop the backup top cover pump is given.

[0103] After step 4 is completed, compare the pump stop time T1 and the pump start time T2 of the main top cover pump, and calculate the leakage amount through linear calculation:

[0104] Step 5, using the formula = By comparing the amount of leakage, an early warning can be issued:

[0105] In the formula, T1-T2 represents the drainage time, and d1 is the elevation difference of the acoustic fingerprint collector installation.

[0106] Since the drainage capacity of the top cover pump is fixed, then when Right now A large number indicates a large leakage. The larger the value, the greater the leakage. The smaller the value, the smaller the leakage.

[0107] After step 5 is completed, the drainage capacity is assessed:

[0108] Step 6, the nth group of events - =

[0109] The (n+1)th group of events - = ;

[0110] when < At that time, the surface of the top cover was not draining enough.

[0111] Conversely, it indicates that the current drainage capacity of the roof is sufficient.

[0112] A detection system for leaking water from the top cover of a hydroelectric turbine unit, employing the aforementioned detection method for leaking water from the top cover of a hydroelectric turbine unit, includes a voiceprint collector, a voiceprint storage module, a voiceprint extraction module, a waveform calculation module, a logic calculation module, and a signal output module. Multiple voiceprint collectors form a voiceprint acquisition array, and the geographical location information of the voiceprint acquisition array serves as an input to the waveform calculation module. The waveform calculation module then... Waveforms from t minutes ago and real-time The waveform calculation at a given time becomes the input to the logic calculation module; the judgment result after logic calculation becomes the input to the signal output module; the signal output module is used to link with the main top cover pump and the standby top cover pump.

[0113] Additionally, the method for determining if the top cover connecting hole is blocked is as follows:

[0114] The typical top cover installation structure is segmented, therefore the top cover water tank is also divided into sections, with each section connected by small connecting holes. Based on the segmented structure of the top cover, the installation positions of the four sets of acoustic signature collectors can be determined to form an acoustic signature collection array. Therefore, by comparing the phase of the acoustic wave signal generated by SC1 in all groups, it can be determined whether the acoustic signature collectors SC1 are all submerged. If they are all submerged, it indicates that the connecting holes are not blocked; if the SC1 of one set of acoustic signature collectors is not submerged, but the SC1 of other sets is submerged, it indicates that the connecting holes leading to that section of the water tank are blocked. In this case, the control module issues a top cover connecting hole blockage signal.

[0115] The above embodiments are merely preferred technical solutions of the present invention and should not be considered as limitations on the present invention. The scope of protection of the present invention should be limited to the technical solutions described in the claims, including equivalent substitutions of the technical features described in the claims. That is, equivalent substitutions and improvements within this scope are also within the scope of protection of the present invention.

Claims

1. A method for detecting water leakage in the top cover of a hydroelectric turbine unit, characterized in that... Includes the following steps: Step 1: Collect the acoustic signature signal of the top cover. The acoustic signature signal includes acoustic signature signal propagated through metal medium, acoustic signature signal propagated through air, and acoustic signature signal propagated through liquid medium. Step 2, Filtering the acoustic signature signal propagated through the metal medium: Based on the speed of sound propagation in different media, the corresponding acoustic signature phase displacement for different media is obtained. The acoustic signature signal propagated through the metal medium is filtered out by the magnitude of the acoustic signature phase displacement. Step 3: Determine if the top cover is leaking: After eliminating the acoustic signal transmitted through the metal medium, continue to judge the remaining acoustic signal based on the phase displacement of the acoustic signal. If the remaining acoustic signal is only the acoustic signal transmitted through the air, it proves that the top cover is not leaking; if the acoustic signal also includes the acoustic signal transmitted through the liquid medium, it proves that the top cover has leaked.

2. The method for detecting leakage in the top cover of a hydroelectric turbine unit according to claim 1, characterized in that: In step 1, multiple sets of voiceprint acquisition arrays are set on the top cover. The number of voiceprint acquisition arrays is at least four. The four sets of voiceprint acquisition arrays are distributed in four directions on the top cover. Each set of voiceprint acquisition arrays includes at least three voiceprint collectors. Each set of voiceprint acquisition arrays consists of three voiceprint acquisition devices, namely SC1, SC2 and SC3; SC1, SC2 and SC3 are installed from bottom to top on the same vertical line, with a distance of d1 meters between each device. The sources of acoustic signals propagating through metallic media are: acoustic signals caused by vibrations during the operation of the turbine unit and acoustic signals caused by vibrations of the roof due to ambient sound waves; The source of the airborne acoustic signature signal is: acoustic wave signal caused by environmental vibration of the hydroelectric power plant; Acoustic signal propagation through liquid medium: the acoustic signal after the acoustic sensor is submerged.

3. The method for detecting leakage in the top cover of a hydroelectric turbine unit according to claim 2, characterized in that: In step 2, the calculation process for the acoustic signature phase displacement is as follows: The relationship between the frequency, wavelength, and velocity of sound waves propagating in different media is as follows: u=λ*ν; u represents wave speed, λ represents wavelength, and ν represents frequency; The signals propagating through the metallic medium acquired by each acoustic signature acquisition array will all undergo corresponding acoustic signature phase shifts due to different distances. These acoustic signature phase shifts satisfy the following: Let any acoustic fingerprint sensor be the origin O, then the vibration at that point is: ; Where A is the amplitude. Angular frequency, The initial phase is given by t, which represents time. Indicates displacement; where A, , It is a fixed value; The vibration at point P of the other voiceprint collector in this group is: ; In the formula, assuming point O is SC1 and point P is the position of SC2, x is equivalent to the distance d1 between SC1 and SC2. If point P is SC3, x is equivalent to the distance 2d1 between SC3 and SC1. Assuming point 0 is SC2 and point P is SC1, x is equivalent to the distance between SC2 and SC1 - d1. If point P is SC3, x is equivalent to the distance between SC3 and SC2 d1. Assuming point 0 is SC3 and point P is SC1, x is equivalent to the distance between SC3 and SC1 - 2d1. If point P is SC2, x is equivalent to the distance between SC2 and SC3 - d1. because = u= ; Therefore, the vibration wave function at point P is: ; Therefore, by analyzing the phase shift of the acoustic signatures from the two acoustic signature collectors using spectral analysis, it is determined whether to filter out acoustic signature signals propagating through metallic media, for the same frequency. The sound wave judgment conditions are as follows: 1) u 钢铁 At a speed of 5000 m / s, a phase displacement of... ; 2) u 水 It is 1500 meters per second. ; 3) u 空气 It is 340 meters per second. ; Compare the sound source signals of the two voiceprint collectors. The one with the smallest phase difference is the sound wave propagated through the metal medium. Filter out the voiceprint signal propagated through the metal medium.

4. The method for detecting leakage in the top cover of a hydroelectric turbine unit according to claim 3, characterized in that: If the top cover is determined to be leaking, then the following steps should be taken: Step 4, the start-up and shutdown conditions for the main top cover pump and the standby top cover pump are as follows: 1) When all SC2 in the 4 sets of acoustic fingerprint acquisition arrays are submerged, it indicates a small amount of water leakage. The main top cover pump is started. When none of the SC2 in the 4 sets of acoustic fingerprint acquisition arrays are submerged, the main top cover pump is stopped. 2) If any SC3 of any 3 sets of acoustic fingerprint collectors is submerged, it indicates a large amount of water leakage, and a high water level alarm signal is given for the top cover, and a command to start the backup top cover pump is given; if the submerged signal of the SC3 of any 3 sets of acoustic fingerprint collectors disappears, a command to stop the backup top cover pump is given.

5. The method for detecting leakage in the top cover of a hydroelectric turbine unit according to claim 4, characterized in that: After step 4 is completed, compare the pump stop time T1 and the pump start time T2 of the main top cover pump, and calculate the leakage amount through linear calculation: Step 5, using the formula = By comparing the amount of leakage, an early warning can be issued: In the formula, T1-T2 represents the drainage time, and d1 is the elevation difference of the acoustic fingerprint collector installation. Since the drainage capacity of the top cover pump is fixed, then when Right now A large number indicates a large leakage. The larger the value, the greater the leakage. The smaller the value, the less water is leaking.

6. The method for detecting leakage in the top cover of a hydroelectric turbine unit as described in claim 5, characterized in that: After step 5 is completed, the drainage capacity is assessed: Step 6, the nth group of events - = The (n+1)th group of events - = ; when < At that time, the surface of the top cover has insufficient drainage capacity; Conversely, it indicates that the current drainage capacity of the roof is sufficient.

7. A detection system for water leakage from the top cover of a hydroelectric turbine unit, characterized in that: The method for detecting leakage of the top cover of a water turbine unit, as described in any one of claims 1-6, includes an acoustic fingerprint collector, an acoustic fingerprint storage module, an acoustic fingerprint extraction module, a waveform calculation module, a logic calculation module, and a signal output module. Multiple voiceprint collectors form a voiceprint acquisition array. The geographical location information of the voiceprint acquisition array serves as an input to the waveform calculation module. The waveform calculation module then... Waveforms from t minutes ago and real-time The waveform calculation at a given time becomes the input to the logic calculation module; the judgment result after logic calculation becomes the input to the signal output module; the signal output module is used to link with the main top cover pump and the standby top cover pump.

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