Anti-blocking method for hydropower station maintenance drainage and hydropower station maintenance drainage system

Abstract

The method comprises the steps that a first pressure value in front of a water inlet of a crushing device and a second pressure value behind a water outlet of the crushing device are obtained, a pressure difference is obtained according to the first pressure value and the second pressure value, and the pressure difference is calculated in a window sliding mode; the change condition of the pressure difference in the preset time window is analyzed, the blockage type is determined according to the pressure difference and the change condition, the control instruction is sent to the crushing device based on the blockage type, the blockage degree can be accurately distinguished, and misjudgment and missed judgment of a single pressure difference threshold value are avoided; adaptive control instructions are issued according to different blockage types, accurate blockage prevention can be achieved, equipment loss caused by invalid operation is avoided, the problems of over-voltage operation, part abrasion reduction, motor overload and the like caused by blockage aggravation are solved, faults caused by blockage are avoided from the source, the equipment start-stop and maintenance frequency is greatly reduced, and the production efficiency is improved. Therefore, blockage prevention is effectively achieved, and the service life of the crushing device is prolonged.

Description

Technical Field

[0001] This invention relates to the field of maintenance drainage technology, and in particular to a method for preventing blockage during maintenance drainage of hydropower stations and a hydropower station maintenance drainage system. Background Technology

[0002] The maintenance drainage system of a hydropower station is used to remove accumulated and leaking water during unit or flow channel maintenance, and is a key auxiliary system to ensure the safe operation of the power station. Traditional maintenance drainage systems typically consist of maintenance pumps and simple trash racks. In actual operation, these systems are easily clogged by debris carried in the water flow (such as branches, plastic bags, and weeds), leading to reduced drainage efficiency or even system failure. If the maintenance pump's pumping time exceeds its allowable continuous operating time, the pump overheats and is forced to stop, resulting in prolonged pumping time and impacting the normal maintenance schedule of the unit. Therefore, existing technology incorporates a crushing device at the inlet of the maintenance pump, which starts and stops synchronously with the pump to crush debris. The crushing device uses a motor to drive the impeller to rotate at high speed, accelerating and throwing out the mud or slurry entering the pump chamber between the impeller blades. When the material impacts the impeller edge, its kinetic energy is converted into pressure energy, and solid particles are crushed under impact and shear forces, ultimately being discharged through the pump casing. This alleviates the clogging problem to some extent, but still has some drawbacks, as follows: (1) The crushing device always starts and stops synchronously with the water pump, and cannot judge the occurrence, type and severity of the blockage in real time. It can only respond passively, which leads to increased wear of the cutting tools. (2) For fine sand, gravel, fibers, etc., direct passage through the crushing device will accelerate their wear; while for oversized hard objects (such as iron rods, large stones), it may cause the cutter head to jam or the motor to burn out due to overload; for different blockages (such as flexible entanglement and hard jamming), the crushing device usually only has one way of handling it (such as increasing torque), resulting in poor anti-blocking effect. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a method and system for preventing blockage during maintenance drainage of hydropower stations, which can more effectively prevent blockage and extend the service life of the crushing device.

[0004] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: A method for preventing blockage during drainage maintenance in a hydropower station includes: Obtain the first pressure value before the inlet of the crushing device and the second pressure value after the outlet; The pressure difference is obtained based on the first pressure value and the second pressure value; The changes in the pressure difference within a preset time window are analyzed using a sliding window method. The type of blockage is determined based on the pressure difference and the changes. Control commands are sent to the crushing device based on the type of blockage.

[0005] To solve the above-mentioned technical problems, another technical solution adopted by the present invention is as follows: A hydropower station maintenance drainage system includes a crushing device and a maintenance pump connected in series in a pumping pipeline, and also includes a pressure sensor, a vibration sensor and a central control unit. The pressure sensor is installed before the inlet and after the outlet of the crushing device. The vibration sensor is mounted on the housing of the drive motor of the crushing device; The central control unit is connected to the pressure sensor, the vibration sensor, the crushing device, and the maintenance pump, and executes each step of the above-described method for preventing blockage during drainage maintenance of a hydropower station.

[0006] The beneficial effects of this invention are as follows: The system acquires the first pressure value before the inlet and the second pressure value after the outlet of the crushing device. Based on these values, a pressure difference is calculated. Using a sliding window approach, the system analyzes the changes in this pressure difference within a preset time window. The type of blockage is determined based on the pressure difference and its changes. Control commands are then sent to the crushing device based on the blockage type. This real-time monitoring of the internal flow resistance of the crushing device via the pressure difference between the inlet and outlet directly reflects the internal blockage trend. Combining this with sliding window analysis of pressure difference changes allows for accurate differentiation of blockage levels, avoiding misjudgments and omissions based on a single pressure difference threshold. By issuing appropriate control commands for different blockage types, precise anti-blockage measures are achieved. This avoids equipment damage caused by ineffective operations and prevents overpressure operation due to escalating blockages, reducing component wear and motor overload. By mitigating blockage-related failures at the source, the system significantly reduces the frequency of equipment start-ups, shutdowns, and maintenance, thus more effectively preventing blockages and extending the service life of the crushing device. Attached Figure Description

[0007] Figure 1 A flowchart illustrating an anti-clogging method for drainage during maintenance of a hydropower station, according to an embodiment of the present invention; Figure 2 This is a schematic diagram of a hydropower station maintenance and drainage system according to an embodiment of the present invention. Detailed Implementation

[0008] To explain in detail the technical content, objectives, and effects of the present invention, the following description is provided in conjunction with the embodiments and accompanying drawings.

[0009] In existing technologies, the crushing devices in the maintenance and drainage systems of existing hydropower stations always start and stop synchronously with the water pumps, making it impossible to judge the occurrence, type and severity of blockages in real time. They can only respond passively, which leads to increased wear on the cutters and a reduced service life. Furthermore, for different types of blockages, such as flexible entanglements and hard jams, the crushing devices usually only have one way of handling them, such as increasing the torque, resulting in poor anti-blockage effects.

[0010] To at least solve the above problems, please refer to Figure 1 This invention provides a method for preventing blockage during drainage maintenance in hydropower stations, comprising: Obtain the first pressure value before the inlet of the crushing device and the second pressure value after the outlet; The pressure difference is obtained based on the first pressure value and the second pressure value; The changes in the pressure difference within a preset time window are analyzed using a sliding window method. The type of blockage is determined based on the pressure difference and the changes. Control commands are sent to the crushing device based on the type of blockage.

[0011] As can be seen from the above description, the beneficial effects of the present invention are as follows: by monitoring the internal flow resistance of the crushing device in real time through the pressure difference between the inlet and outlet, the increase in pressure difference directly reflects the internal blockage trend. Combined with the analysis of pressure difference changes by the sliding window, the degree of blockage can be accurately distinguished, avoiding misjudgment and omission based on a single pressure difference threshold. Adaptive control commands are issued for different types of blockage, which can achieve precise anti-blockage. This avoids equipment damage caused by ineffective operation and prevents overpressure operation caused by increased blockage, reducing problems such as component wear and motor overload. It avoids failures caused by blockage from the source, significantly reduces the frequency of equipment start-up, shutdown and maintenance, thereby more effectively preventing blockage and extending the service life of the crushing device.

[0012] Furthermore, analyzing the changes in the pressure difference within a preset time window using a sliding window method includes: Using a sliding window approach, calculate the discrete first derivative, total increase, and average rate of change of the pressure difference within a preset time window; Determine whether the percentage of times the discrete first derivative is greater than zero within a preset time window exceeds a first preset percentage. If so, determine whether the total increase exceeds a first preset amplitude threshold. If so, determine whether the average rate of change is greater than a preset lower limit of the rate of change and less than a preset upper limit of the rate of change. If so, determine that the change in pressure difference is a continuous increase.

[0013] As described above, by calculating the discrete first derivative, total increase, and average rate of change of the pressure difference through a sliding window, the continuous increase of the pressure difference can be determined from three dimensions: trend, magnitude, and rate of change. This avoids misjudgment based on a single indicator and accurately captures the true trend of blockage development. Combining this with the proportion of times the first derivative is positive can eliminate interference from occasional fluctuations, ensuring that the judgment is a continuous increase rather than an instantaneous anomaly. Threshold verification of the total increase and average rate of change can determine whether the magnitude and rate of increase in pressure difference reach the blockage warning standard, thus achieving accurate and stable identification of mild blockage.

[0014] Furthermore, determining the blockage type based on the pressure difference and the changes includes: If the pressure difference continues to increase and exceeds a first preset threshold, then the blockage type is determined to be mild blockage.

[0015] As described above, combining the trend of continuously increasing differential pressure with the numerical condition of differential pressure exceeding the first preset threshold to determine mild blockage is more accurate, avoids misjudgment due to instantaneous fluctuations of a single numerical threshold, and also prevents early warning delays caused by looking only at trends without quantitative standards.

[0016] Furthermore, analyzing the changes in the pressure difference within a preset time window using a sliding window method includes: The increase in pressure difference within a preset time window at the first preset time is calculated using a sliding window method. Determine whether the increase in the pressure difference within a preset time window exceeds a second preset amplitude threshold in the first preset time, or whether the increase in the pressure difference within a second preset time window continuously exceeds a third preset amplitude threshold in the first preset time. If so, determine that the change in the pressure difference is a sharp increase.

[0017] As described above, by judging the pressure difference increase at different time dimensions, the characteristics of a sharp increase in pressure difference can be accurately captured, effectively distinguishing instantaneous fluctuations from real sudden blockage trends, avoiding misjudgments, and achieving timely and accurate judgment of severe blockages. This provides a reliable basis for issuing emergency anti-blockage commands, preventing serious damage such as equipment overpressure and component jamming caused by the instantaneous aggravation of blockages. At the same time, it avoids the problem of missed judgments by judging a single increase threshold, improves the response efficiency to severe blockages, and ensures the safe operation of the crushing device.

[0018] Furthermore, determining the blockage type based on the pressure difference and the changes includes: If the pressure difference increases sharply, or if the pressure difference exceeds a second preset threshold, then the blockage type is determined to be severe blockage.

[0019] As described above, the system uses a logic of either a sharp increase in differential pressure or a differential pressure exceeding a second preset threshold to determine severe blockage. This dual-dimensional approach covers two types of severe blockage scenarios: sudden changes and severe sludge accumulation. It can quickly identify sudden increases in differential pressure, such as large particles getting stuck, and accurately determine blockages that have accumulated to a severe degree, thus triggering a severe blockage warning immediately.

[0020] Furthermore, before determining the blockage type based on the pressure difference and the changes, the process also includes: Obtain the vibration signal of the drive motor of the crushing device; Calculate the overall vibration level and energy of key characteristic frequency bands of the vibration signal at a third preset time. If the overall vibration level exceeds a third preset threshold, then the vibration signal is determined to be significantly enhanced. If not, then the baseline vibration level is obtained, and it is determined that the growth factor of the overall vibration level relative to the baseline vibration level reaches or exceeds a first preset factor. If it reaches or exceeds a first preset factor, then the vibration signal is determined to be significantly enhanced. If not, then it is determined that the growth factor of the real-time energy of any key characteristic frequency band relative to the baseline energy of that frequency band reaches or exceeds a second preset factor. If so, then the vibration signal is determined to be significantly enhanced.

[0021] As described above, by determining whether the vibration signal of the drive motor is significantly enhanced from multiple dimensions, the abnormal vibration of the motor caused by blockage can be accurately captured, and invalid vibration signals such as environmental interference can be eliminated, thereby improving the accuracy of vibration determination.

[0022] Furthermore, determining the blockage type based on the pressure difference and the changes includes: If the pressure difference increases sharply and exceeds a second preset threshold, and the vibration signal is significantly enhanced, then the blockage type is determined to be severe blockage.

[0023] As described above, a triple logic of rapidly increasing differential pressure, differential pressure exceeding the second threshold, and significantly enhanced vibration signal is used to determine severe blockage. This achieves multi-dimensional cross-verification, completely eliminating the possibility of misjudgment by a single indicator, accurately identifying the true severe blockage (such as large particle jamming or severe channel stagnation), and avoiding unnecessary emergency intervention triggered by instantaneous fluctuations.

[0024] Furthermore, the blockage types include no blockage, mild blockage, and severe blockage; Sending control commands to the crushing device based on the blockage type includes: If the blockage type is mild blockage, a first control command is generated and sent to the crushing device. The first control command is a command to control the drive motor to perform short-term alternating forward and reverse operation or to increase the speed. If the blockage type is severe blockage, a second control command is generated and sent to the crushing device, and an alarm signal is generated at the same time. The second control command is to execute a protective shutdown command. If the blockage type is "no blockage", a third control command is generated and sent to the crushing device. The third control command is an intermittent operation command.

[0025] As described above, adaptive control commands are issued according to the levels of no blockage, mild blockage, and severe blockage, achieving precise and tiered blockage management and avoiding the inefficiency or over-operation of a single intervention method. Mild blockage is cleared gently by alternating forward and reverse rotation of the motor / increasing the speed, without stopping the machine and ensuring continuous operation of the equipment. Severe blockage results in an immediate protective shutdown and alarm, preventing serious failures such as motor burnout and component wear caused by jamming and overvoltage. When there is no blockage, intermittent operation is performed to reduce equipment idling losses, lower energy consumption and mechanical wear, improve the effectiveness of anti-blockage, reduce system ineffective losses, and effectively extend the overall service life of the crushing device.

[0026] Furthermore, it also includes: Determine whether a tool wear signal from the crushing device has been received. If so, record the alarm information and generate a maintenance reminder signal.

[0027] As described above, adding a tool wear signal detection and alert step can promptly detect tool wear faults, prevent worn tools from becoming clogged due to reduced cutting ability, and prevent the continued operation of worn tools from causing cascading damage to equipment components, thus reducing the risk of cumulative faults.

[0028] Please refer to Figure 2 Another embodiment of the present invention provides a hydropower station maintenance drainage system, including a crushing device and a maintenance pump connected in series in a pumping pipeline, and also includes a pressure sensor, a vibration sensor and a central control unit. The pressure sensor is installed before the inlet and after the outlet of the crushing device. The vibration sensor is mounted on the housing of the drive motor of the crushing device; The central control unit is connected to the pressure sensor, the vibration sensor, the crushing device, and the maintenance pump, and executes each step of the above-described method for preventing blockage during drainage maintenance of a hydropower station.

[0029] The anti-clogging method and drainage system for hydropower station maintenance described above are applicable to hydropower station maintenance drainage scenarios. The specific implementation methods are described below: Please refer to Figure 1 One embodiment of the present invention is as follows: A method for preventing blockage during drainage maintenance in a hydropower station includes: S1. Obtain the first pressure value before the inlet of the crushing device and the second pressure value after the outlet.

[0030] S2. Obtain the pressure difference based on the first pressure value and the second pressure value.

[0031] In one alternative implementation, it further includes: The pressure difference is filtered to eliminate high-frequency noise and instantaneous pulsations, resulting in a smooth pressure difference.

[0032] The filtered pressure difference can be used in subsequent steps.

[0033] S3. Analyze the changes in the pressure difference within a preset time window using a sliding window method, specifically including S31-S34: S31. Using a sliding window method, calculate the discrete first derivative (instantaneous rate of change), total increase, and average rate of change of the pressure difference within a preset time window.

[0034] The formula for calculating the average rate of change is as follows: ; In the formula, This represents the average rate of change of the pressure difference. This represents the total increase in pressure differential. This indicates the preset time window.

[0035] In one alternative implementation, the preset time window is 30 seconds.

[0036] S32. Determine whether the percentage of times the discrete first derivative is greater than zero within the preset time window exceeds a first preset percentage. If so, determine whether the total increase exceeds a first preset amplitude threshold. If so, determine whether the average rate of change is greater than a preset lower limit of the rate of change and less than a preset upper limit of the rate of change. If so, determine that the pressure difference is continuously increasing. Otherwise, execute S33.

[0037] In one optional implementation, the first preset percentage is 70%; the first preset amplitude threshold is 0.03 MPa; the preset rate of change lower limit is 0.0005 MPa / s, and the preset rate of change upper limit is 0.01 MPa / s. The preset rate of change upper limit is a relatively high and sharp threshold, and the preset rate of change lower limit is the system noise floor.

[0038] S33. Calculate the increase in pressure difference within a preset time window at the first preset time using a sliding window method.

[0039] In one alternative implementation, the first preset time is 5 seconds.

[0040] S34. Determine whether the increase in pressure difference within the preset time window exceeds the second preset amplitude threshold in the first preset time, or whether the increase in pressure difference within the second preset time window continuously exceeds the third preset amplitude threshold in the first preset time. If so, determine that the change in pressure difference is a sharp increase.

[0041] In one optional implementation, the second preset amplitude threshold is 0.04 MPa; the second preset time is 10 seconds; and the third preset amplitude threshold is 0.02 MPa.

[0042] In one alternative implementation, step S4 is followed by: Obtain the vibration signal of the drive motor of the crushing device; Calculate the overall vibration level and key characteristic frequency bands (such as: the fundamental frequency of the cutterhead rotation, the passing frequency of the blade and the frequency band where its harmonics are located, or the high-frequency broadband reflecting the impact) of the vibration signal at the third preset time. If the overall vibration level exceeds a third preset threshold, then the vibration signal is determined to be significantly enhanced. If not, then the baseline vibration level is obtained, and it is determined that the growth factor of the overall vibration level relative to the baseline vibration level reaches or exceeds a first preset factor. If it reaches or exceeds a first preset factor, then the vibration signal is determined to be significantly enhanced. If not, then it is determined that the growth factor of the real-time energy of any key characteristic frequency band relative to the baseline energy of that frequency band reaches or exceeds a second preset factor. If so, then the vibration signal is determined to be significantly enhanced.

[0043] The baseline vibration level is obtained as follows: During normal operation without blockages, the vibration signal of the drive motor of the crushing device is continuously recorded; The effective vibration value (RMS) of the vibration signal in each frequency band is calculated as a baseline vibration level. In an optional embodiment, the frequency bands may include those related to the cutter head rotation frequency and its harmonics.

[0044] The increase factor of the overall vibration level relative to the baseline vibration level is specifically: ; In the formula, For the overall vibration level, This indicates the baseline vibration level.

[0045] In one optional implementation, the overall vibration level is a broadband RMS value. The third preset threshold is 10 m / s². 2The threshold corresponds to the dangerous vibration limit of the equipment's mechanical structure; the first preset multiple is 3, that is, the vibration level surges to 3 times or more of the baseline value.

[0046] S4. Determine the blockage type based on the pressure difference and the change, wherein the blockage type includes no blockage, slight blockage, and severe blockage, specifically including S41-S43: S41. If the pressure difference is continuously increasing and exceeds a first preset threshold, then the blockage type is determined to be mild blockage.

[0047] In one optional implementation, the first preset threshold is 0.05 MPa.

[0048] S42. If the pressure difference increases sharply, or the pressure difference exceeds the second preset threshold, then the blockage type is determined to be severe blockage.

[0049] In one optional implementation, the second preset threshold is 0.15 MPa.

[0050] S43. If the pressure difference increases sharply and exceeds the second preset threshold, and the vibration signal is significantly enhanced, then the blockage type is determined to be severe blockage.

[0051] S44. If a microswitch trigger signal is received from the primary grille, the blockage type is determined to be severe blockage.

[0052] S45. If the pressure difference is less than or equal to the first preset threshold, the pressure difference does not continuously increase, the pressure difference is less than or equal to the second preset threshold, the pressure difference does not increase sharply, the vibration signal does not significantly increase, and no microswitch trigger signal or tool wear signal is received from the primary grid, then the blockage type is determined to be no blockage.

[0053] S5. Send control commands to the crushing device based on the blockage type, specifically including S51-S53: S51. If the blockage type is mild blockage, a first control command is generated and sent to the crushing device. The first control command is a command to control the drive motor to run in alternating forward and reverse directions for a short time or to increase the speed, so as to attempt to tear and remove the entangled material.

[0054] In one optional implementation, sending the first control command to the crushing device also includes: Send a command to increase the pump power for a preset time period to the pump so as to utilize the pump's impact on the pipeline.

[0055] S52. If the blockage type is severe blockage, a second control command is generated and sent to the crushing device. At the same time, an alarm signal is generated. The second control command is a protective shutdown command.

[0056] The alarm signal can be an audible and visual alarm, indicating the specific fault type (such as "hard object blocking, please check the primary grille"), and automatically prompting manual opening of the bypass cleaning port.

[0057] S53. If the blockage type is no blockage, a third control command is generated and sent to the crushing device. The third control command is an intermittent operation command.

[0058] In one alternative implementation, the third control command may also be a low-speed operation command, where low speed is a speed lower than the normal operating speed.

[0059] In one alternative implementation, it further includes: Determine whether a tool wear signal from the crushing device has been received. If so, record the alarm information and generate a maintenance reminder signal.

[0060] In one optional implementation, it may further include recording all alarm events, differential pressure trends, runtime, and other data to form a device health record. It supports uploading data to a cloud monitoring platform via an IoT module to achieve remote status monitoring and fault diagnosis.

[0061] The basic components of existing crushing devices typically include: Shell and flow channel: A cylindrical or box-shaped shell with flanges at both ends is used to connect the inlet pipe and the outlet pipe to form a water flow channel; Single crushing mechanism: The housing typically houses only one main crushing disc (or cutter) driven by a motor. All debris entering the device, regardless of size or hardness, is crushed in a single pass by this disc. Simple protective devices: Some devices may have a fixed trash rack (grid) on the water inlet side, but the rack is usually welded or fixed to the shell and can only block huge debris that is far larger than the diameter. It cannot provide effective protection for hard objects that may jam the cutter head but are slightly smaller, and once jammed, it is extremely difficult to clean. Basic anti-backflow mechanism: A mechanical check valve (such as a swing check valve) is usually installed after the outlet of the crushing device or at the outlet of the water pump. This valve relies entirely on the force of the water flow to open and close. It has a single function, cannot be actively controlled, and is prone to water hammer when closed quickly.

[0062] While retaining the core function of the original crushing device (i.e., crushing debris by rotating the cutter head), the present invention has made structural enhancements, as detailed below.

[0063] According to another aspect of the invention, Figure 2 This is a schematic diagram illustrating a hydropower station maintenance drainage system according to an embodiment of the present invention. The system includes a crushing device and a maintenance pump connected in series in a pumping pipeline. It is characterized by further including a pressure sensor, a vibration sensor, and a central control unit. The pressure sensor is disposed before the inlet and after the outlet of the crushing device. The vibration sensor is disposed on the housing of the drive motor of the crushing device. The central control unit is connected to the pressure sensor, the vibration sensor, the crushing device, and the maintenance pump, respectively, and executes the various steps of the aforementioned anti-clogging method for hydropower station maintenance drainage.

[0064] In an alternative embodiment, an image recognition unit is also included, which captures images of the incoming debris via a waterproof camera mounted in front of the inlet of the crushing device.

[0065] In one optional embodiment, a primary screen is also included, which is installed inside the housing of the crushing device and located upstream of the main crushing disc (in the water inlet direction), specifically in the cavity between the water inlet flange and the main crushing disc.

[0066] In an optional embodiment, an elastic support mechanism is also included, which is connected between the frame of the primary bar and the housing of the crushing device. For example, a four-corner arrangement of compression springs or rubber dampers can be used to give the entire primary bar a limited elastic displacement stroke (e.g., 20-50 mm) in the axial direction (water flow direction).

[0067] In an alternative embodiment, a microswitch is also included, which is fixedly mounted on the housing of the crushing device, and its trigger probe is precisely aligned with the position reached by the primary grid when the maximum permissible displacement occurs.

[0068] In an alternative embodiment, a bypass sluice gate is further included, which is located on the side of the crusher housing, directly opposite the accumulation chamber area between the primary grid and the main crushing disc. The opening of the bypass sluice gate is connected via a flange to an electrically operated drain valve or a bolt-sealed cover.

[0069] Water first passes through a primary screen, whose gaps are slightly larger than the main crushing disc's design allow for particle size interception of oversized hard objects (such as stones and iron rods) larger than the disc's processing capacity. Allowed-through debris proceeds to the next stage, thus achieving graded interception. When an oversized hard object becomes stuck on the primary screen, the water flow is obstructed, increasing the pressure difference across the screen. When this pressure difference exceeds a preset threshold (such as spring preload) of the elastic support mechanism, the screen is pushed, displacing along the water flow direction. When the displacement reaches a set value, the screen frame presses against the probe of a microswitch, actuating its contacts to detect the obstruction and trigger a signal. The microswitch's electrical signal wire is connected to the DI (Digital Input) module of the central control unit, sending a "hard object obstruction" switching signal for signal transmission. Upon receiving the signal, the central control unit can immediately, or after manual confirmation, send a command to the electric drain valve to open it. At this point, the hard object stuck in front of the screen, along with some water flow, can be discharged outside the system through the bypass cleaning port, quickly releasing pressure and providing a manual cleaning channel without disassembling the entire device.

[0070] In an optional embodiment, a wear-resistant conductive material layer is further included, which is attached to the cutting edge working surface of each tooth of the main crushing disc by an inlay or welding process. The wear-resistant conductive material layer has high hardness, high wear resistance, and is conductive, such as tungsten carbide.

[0071] In one alternative embodiment, the base material of the cutting teeth (such as high-strength alloy steel) serves as an insulating substrate.

[0072] In an optional embodiment, a circuit detection circuit is further included, comprising a conductive slip ring mounted on the rotating shaft (electrically connected to the cutter head), a brush fixed to the housing (in contact with the slip ring), and an external low-voltage DC power supply and signal detection circuit. The circuit detection circuit is connected in series with the conductive layer of the cutter teeth.

[0073] Normal state: When the cutting teeth are not worn to their limit, current flows from the positive terminal of the power supply. brush slip ring Cutterhead base Conductive layer of all blades Forming parallel circuits Return to the negative power supply. The detection circuit detects a stable low resistance state. Wear alarm state: When the wear-resistant conductive material layer of a certain cutting tooth is completely worn through, exposing the underlying insulating substrate, current cannot pass through that cutting tooth, causing a step increase in resistance or an open circuit in the entire detection circuit. When the detection circuit detects this resistance change, it generates a cutting tool wear signal and sends it to the central control unit.

[0074] In one alternative implementation, the simple mechanical check valve in the original system is replaced with an electrically controlled butterfly valve or a hydraulically controlled slow-closing valve. The electrically controlled butterfly valve or hydraulically controlled slow-closing valve is installed on the pipeline after the outlet of the crushing device and before the inlet of the maintenance pump.

[0075] The drive mechanism (electric actuator or electromagnetic hydraulic control unit) of the electrically controlled butterfly valve or hydraulically controlled slow-closing valve is connected to the DO (digital output) module or dedicated control module of the central control unit via a control cable. Active control: The central control unit can actively control the opening and closing of the valve according to system logic. For example: before system startup, the valve can be opened to a certain angle; during normal system shutdown, a command can be sent to slowly close the valve (slow-closing function), effectively eliminating water hammer pressure waves and protecting pipelines and equipment; during emergency system shutdown (such as severe blockage), the valve can be immediately closed to cut off the backflow path and prevent backflow into the pump chamber. This valve also inherits the anti-backflow function of the original check valve, but its operation is more reliable and controllable, upgrading from a passive component to a controlled active actuator.

[0076] This invention achieves intelligent and highly reliable operation of the core crushing device through a triple structural upgrade of the inlet stage (adding elastic grid and bypass), the core stage (adding wear monitoring to the cutter head), and the outlet stage (upgrading controllable valves), and deep integration with the central control unit, providing a solid hardware foundation for the intelligent control strategy of the entire system.

[0077] In summary, the anti-clogging method and drainage system for hydropower station maintenance described above, through the collaborative analysis of multiple sensors (pressure, vibration), achieves real-time and accurate diagnosis of clogging conditions. It can obtain the degree of clogging immediately, preventing the system from operating blindly and achieving an improvement from "passive clogging handling" to "active early warning and adaptive handling." The addition of a primary screen and over-limit protection mechanism, through dual protection combining mechanical (primary screen) and electrical (intelligent sensing), effectively avoids the risk of damage to the core crushing mechanism due to oversized hard objects. The electrically controlled anti-backflow mechanism further eliminates water hammer hazards, greatly improving the overall reliability and fault response capability of the system. Adaptive adjustment of the operating strategy according to actual working conditions significantly reduces ineffective operating time and energy consumption. Tool wear monitoring enables on-demand replacement, realizing a shift from "periodic maintenance" to "condition-based maintenance," avoiding over-maintenance or sudden failure, and extending the service life of the crushing device.

[0078] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent modifications made based on the content of the present invention specification and drawings, or direct or indirect applications in related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A method for preventing clogging of water power plant maintenance drainage, characterized by, The method comprises: obtaining a first pressure value before a water inlet of a crushing device and a second pressure value after a water outlet of the crushing device; obtaining a pressure difference according to the first pressure value and the second pressure value; analyzing a change of the pressure difference in a preset time window in a sliding window manner; determining a blockage type according to the pressure difference and the change; sending a control instruction to the crushing device based on the blockage type.

2. The anti-clogging method for overhauling and draining a hydroelectric power station according to claim 1, characterized in that, The analyzing a change of the pressure difference in a preset time window in a sliding window manner comprises: calculating a discrete first-order derivative, a total amplitude and an average change rate of the pressure difference in a preset time window in a sliding window manner; judging whether a proportion of times that the discrete first-order derivative is greater than zero in the preset time window exceeds a first preset percentage, if yes, judging whether the total amplitude exceeds a first preset amplitude threshold, if yes, judging whether the average change rate is greater than a preset lower limit of change rate and less than a preset upper limit of change rate, if yes, determining that the change of the pressure difference is continuously increasing.

3. The anti-clogging method for overhauling and draining a hydroelectric power station according to claim 2, characterized in that, The determining a blockage type according to the pressure difference and the change comprises: if the change of the pressure difference is continuously increasing and the pressure difference exceeds a first preset threshold, determining that the blockage type is mild blockage.

4. The anti-clogging method for overhauling the drainage of a hydroelectric power station according to claim 1, characterized in that, The analyzing a change of the pressure difference in a preset time window in a sliding window manner comprises: calculating an amplitude of the pressure difference at a first preset time in a preset time window in a sliding window manner; judging whether the amplitude of the pressure difference at the first preset time in the preset time window exceeds a second preset amplitude threshold, or whether the amplitude of the pressure difference at the first preset time continuously exceeds a third preset amplitude threshold in a second preset time, if yes, determining that the change of the pressure difference is sharply increasing.

5. The anti-clogging method for overhauling the drainage of a hydroelectric power station according to claim 4, characterized in that, The determining a blockage type according to the pressure difference and the change comprises: if the change of the pressure difference is sharply increasing or the pressure difference exceeds a second preset threshold, determining that the blockage type is severe blockage.

6. The anti-clogging method for overhauling the drainage of a hydroelectric power station according to claim 4, characterized in that, Before the determining a blockage type according to the pressure difference and the change, the method further comprises: obtaining a vibration signal of a driving motor of the crushing device; calculating a total vibration level at a third preset time and an energy of a key characteristic frequency band of the vibration signal; judging whether the total vibration level exceeds a third preset threshold, if yes, determining that the vibration signal is significantly enhanced, if not, obtaining a baseline vibration level, and judging whether a growth multiple of the total vibration level relative to the baseline vibration level reaches or exceeds a first preset multiple, if yes, determining that the vibration signal is significantly enhanced, if not, judging whether a growth multiple of a real-time energy of any of the key characteristic frequency bands relative to a baseline energy of the frequency band reaches or exceeds a second preset multiple, if yes, determining that the vibration signal is significantly enhanced.

7. The anti-clogging method for overhauling the drainage of a hydroelectric power station according to claim 6, characterized in that, The determining a blockage type according to the pressure difference and the change comprises: if the change of the pressure difference is sharply increasing and the pressure difference exceeds a second preset threshold, and the vibration signal is significantly enhanced, determining that the blockage type is severe blockage.

8. The anti-clogging method for overhauling the drainage of a hydroelectric power station according to claim 1, characterized in that, The blockage type comprises no blockage, mild blockage and severe blockage. The sending a control instruction to the crushing device based on the blockage type comprises: If the blockage type is the slight blockage, a first control instruction is generated and sent to the crushing device, the first control instruction being an instruction for controlling the driving motor to perform short-time positive and negative rotation alternation or to increase the rotating speed; If the blockage type is the severe blockage, a second control instruction is generated and sent to the crushing device, and an alarm signal is generated, the second control instruction being an instruction for performing protective shutdown; If the blockage type is the no blockage, a third control instruction is generated and sent to the crushing device, the third control instruction being an intermittent operation instruction.

9. The anti-clogging method for overhauling the drainage of a hydroelectric power station according to claim 1, characterized in that, Further comprising: judging whether a cutter wear signal of the crushing device is received, if yes, recording alarm information and generating a maintenance signal.

10. A power plant maintenance drainage system comprising a breaking device and a maintenance pump connected in series in a pumping line, characterized in that, Further comprising a pressure sensor, a vibration sensor and a central control unit; the pressure sensor is arranged before a water inlet of the crushing device and after a water outlet of the crushing device; the vibration sensor is arranged on a shell of a driving motor of the crushing device; the central control unit is connected with the pressure sensor, the vibration sensor, the crushing device and the maintenance pump respectively, and performs each step in the anti-blocking method for maintenance drainage of a hydropower station according to any one of claims 1 to 9.

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