Self-excited vibration monitoring and protection method for ball valve of pumped storage power station

Abstract

The invention discloses a self-excited vibration monitoring and protecting method for a ball valve of a pumped storage power station, and relates to the technical field of valve monitoring. The system comprises a monitoring module and a monitoring method. The monitoring module comprises a pressure sensor and a displacement sensor. The monitoring method comprises the steps that a 1 # unit is in a phase modulation or shutdown state, other units are in a phase modulation or shutdown state, and when ball valves of the 1 # unit are all closed and the upstream pressure is larger than a first pressure threshold value, an alarm signal is triggered; when the ball valve of the 1 # unit is fully closed and the pressure of a working seal exit cavity is greater than a pressure threshold value II, or a seal exit switch acts, an alarm signal is triggered; when the ball valve of the 1 # unit is fully closed and the upstream pressure and the displacement of the ball valve are combined in an over-limit manner; and when the pressure of the extension section of the water inlet valve is greater than a pressure threshold value III and the displacement of the ball valve exceeds a distance threshold value I, delaying for a period of time and triggering an alarm signal. The operation safety and stability of the ball valve of the pumped storage power station are remarkably improved, and efficient and reliable operation of the power station is guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of valve monitoring, and in particular to a method for monitoring and protecting the self-excited vibration of a ball valve in a pumped storage power station. Background Art

[0002] In the operation of a pumped storage power station, the water inlet valve is one of the most critical components, and its performance directly affects the safety and efficiency of the power station. Especially for units with multiple units connected by one pipe, the importance of the water inlet valve is self-evident. Self-excited vibration may cause damage to the water inlet valve or even the entire power station system. Therefore, how to prevent and deal with self-excited vibration has become an important issue in power station operation. The ball valve system of a pumped storage power station adopts a pressure steel pipe, a sealing chamber and a displacement monitoring device. The monitoring system collects pressure signals (such as the working seal injection and withdrawal chamber pressure, the ball valve upstream pressure) and displacement signals. To set the hydraulic self-excited vibration alarm criteria, the existing solution is mainly achieved through the following measures: 1. Install a pressure sensor on the upstream extension section of the ball valve and preset a pressure pulsation alarm; 2. Install pressure sensors in the sealing injection and withdrawal circuits and set low pressure differential alarms; 3. Real-time monitoring of working seal operating water pressure through monitoring system. Insufficient existing technology: 1. Isolated monitoring parameters: Existing solutions rely solely on single pressure or displacement signals and lack a multi-parameter collaborative analysis mechanism, making them unable to accurately capture the complex characteristics of self-excited vibrations. For example, sudden pressure changes that are out of sync with excessive displacement are prone to being missed.

[0003] 2. Response lag: The manual handling process relies on the judgment of the operator. It takes minutes to respond from the alarm to the execution of seal exit or the start of the booster pump, while self-excited vibration can cause equipment damage within seconds. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for monitoring and processing the self-excited vibration of ball valves in pumped-storage power stations, aiming to solve the problems in the existing technology of isolated monitoring parameters, inability to accurately capture the complex characteristics of self-excited vibrations, response lag, and difficulty in taking effective measures in time before self-excited vibrations cause damage to equipment, thereby significantly improving the safety and stability of the operation of ball valves in pumped-storage power stations and ensuring efficient and reliable operation of the power station.

[0005] The present invention is achieved through the following technical solutions: A method for monitoring and protecting the self-excited vibration of a ball valve in a pumped storage power station, comprising a monitoring module and a monitoring method. The monitoring module includes: A pressure sensor and a displacement sensor, wherein the pressure sensor monitors the upstream pressure of the water valve and the pressure in the working sealing chamber of the water valve, and the displacement sensor monitors the displacement of the water valve body; The monitoring method comprises: Unit 1 is in phase adjustment or shutdown state, and other units are in phase adjustment or shutdown state. When the ball valve of unit 1# is fully closed and the upstream pressure is greater than the pressure threshold 1, alarm signal 1 is triggered; When the ball valve of unit 1# is fully closed and the pressure in the working seal exit chamber is greater than the second pressure threshold, or the seal exit switch is actuated, alarm signal 2 is triggered; When the ball valve of unit 1# is fully closed and the upstream pressure and the displacement of the ball valve exceed the limit combination: when the pressure of the water inlet valve extension section is greater than the pressure threshold 3 and the displacement of the ball valve exceeds the distance threshold 1, the alarm signal 3 is triggered after a delay.

[0006] Furthermore, in the present invention, the above also includes a processing method: The composite trigger mechanism is that if any signal rising edge is triggered ≥3 times within 20 seconds, it is judged as self-excited vibration. If the pressure of the upstream pressure pipe of the ball valve is greater than the pressure threshold 1, each time a rising edge of pressure change is detected, the pressure limit mark of the upstream pressure pipe of the ball valve is counted up by 1; when the downstream seal detects the exit signal action (rising edge), the exit mark of the downstream seal of the ball valve is counted up by 1; When the pressure limit mark of the upstream pressure steel pipe of the ball valve and the seal exit mark of the downstream ball valve are greater than 2, the ball valve self-excited vibration start signal is continuously output as 1, that is, after the pressure limit of the upstream pressure steel pipe of the ball valve is detected, or the seal exit of the downstream ball valve is detected, if the rising edge of the above signal is triggered 3 times within 20s, it is considered that the ball valve self-excited vibration exists.

[0007] Furthermore, in the present invention, the above also includes an execution method: When the ball valve self-excited vibration opening signal output is continuously 1: S1. First, start the automatic control process and switch the operating water source to exit the working seal; S2. If the ball valve working seal cannot be withdrawn in step S1, the booster pump is activated in time to increase the withdrawal chamber pressure to withdraw the working seal; S3. If the working seal still cannot be withdrawn in step S2, quickly start the upstream maintenance seal; S4. If the self-oscillation phenomenon cannot be eliminated after the above steps S1, S2, and S3, the ball valves of other units in the same water unit are opened, and the unit is opened in the turbine direction.

[0008] Furthermore, in the present invention, when the pressure limit mark of the pressure steel pipe upstream of the ball valve and the seal exit mark of the ball valve downstream are counted > 0, the timing starts, and the counting mark is cleared after 20 seconds.

[0009] Furthermore, in the present invention, when the pressure is less than the pressure threshold value 1, and the working seal exit signal is reset, and the 20s delay is satisfied, the self-excited vibration signal of the reset ball valve is issued.

[0010] Furthermore, in the present invention, the above-mentioned pressure threshold 1 is 1.2 times the maximum head pressure of the pumped storage power plant.

[0011] Furthermore, in the present invention, when the ball valve of unit 1# is fully closed and the upstream pressure and the displacement of the ball valve exceed the limit combination: When the pressure in the extension section of the water inlet valve is greater than 6.24Mpa and the displacement of the ball valve exceeds 3.57mm, the alarm signal will be triggered after a delay of 20s.

[0012] Furthermore, in the present invention, when the pressure in the extension section of the water inlet valve is greater than 5.2 MPa and the displacement of the ball valve exceeds 3.29 mm, an alarm signal is triggered with a delay of 20 seconds.

[0013] Furthermore, in the present invention, the second pressure threshold is 0.1 MPa.

[0014] Furthermore, in the present invention, any one of the above-mentioned trigger alarm signals will trigger the self-excited vibration alarm, and when both are reset, the self-excited vibration alarm is reset.

[0015] Compared with the prior art, the present invention has the following advantages and beneficial effects: Multi-parameter collaborative monitoring: This invention employs multiple pressure and displacement sensors in the sensing layer (monitoring module) to simultaneously collect multiple parameters, including ball valve upstream pressure, working seal chamber pressure, and ball valve displacement. A three-level dynamic decision logic is then implemented in the control layer (monitoring method) to comprehensively analyze the relationships between these parameters. Compared to existing technologies that rely solely on single-parameter monitoring, this invention more comprehensively and accurately captures the complex characteristics of self-excited vibration, significantly reducing the risk of missed reports and significantly improving the accuracy and reliability of self-excited vibration monitoring.

[0016] Rapid Response Mechanism: A composite triggering mechanism is employed at the execution layer (processing and execution methods), enabling rapid determination of self-excited vibration within 20 seconds. Once self-excited vibration is determined to have occurred, a series of response measures are automatically executed according to pre-set operational procedures, including switching the operating water source, activating the booster pump, inspecting and sealing upstream, and opening the ball valves of other units in the same water unit. The entire response process, from signal monitoring to execution, is automatically completed by the system, reducing response time from minutes to seconds compared to existing technologies. Effective measures can be taken before self-excited vibration causes serious damage to equipment, significantly improving the protection of the ball valve equipment in pumped-storage power plants and ensuring the safe and stable operation of the power plants. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the following briefly introduces the drawings required for use in the examples. It should be understood that the following drawings only illustrate certain embodiments of the present invention and should not be considered as limiting the scope. A person of ordinary skill in the art can also derive other relevant drawings based on these drawings without inventive effort. In the drawings: Figure 1 This is a schematic diagram of the control flow of the alarm signal 1 of the present invention; Figure 2 This is a schematic diagram of the control flow of the alarm signal 2 of the present invention; Figure 3 This is a schematic diagram of the control flow of the alarm signal 3 of the present invention; Figure 4 Schematic diagram of the principle of the self-excited vibration action of the ball valve of the present invention; Figure 5 Schematic diagram of the execution method of the present invention. DETAILED DESCRIPTION

[0018] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with examples and drawings. The exemplary embodiments of the present invention and their descriptions are only used to explain the present invention and are not intended to limit the present invention.

[0019] The following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort shall fall within the scope of protection of the present invention.

[0020] It should be noted that similar numbers and letters represent similar items in the following figures. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. In the description of the embodiments of the present invention, it should also be noted that, unless otherwise clearly specified and limited, the terms "setting", "installation" and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a connection between the two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0021] Example Reference Figures 1 to 5As shown, a method for monitoring and protecting the self-excited vibration of a ball valve in a pumped storage power station provided by an embodiment of the present invention is described in detail as follows.

[0022] The monitoring module consists of two parts: a pressure sensor and a displacement sensor.

[0023] Pressure sensor: Use high-precision, high-stability pressure sensors. For example, the pressure sensor installed upstream of the ball valve has a measurement range of 0-10MPa and an accuracy of ±0.01MPa, which can accurately sense small changes in the pressure upstream of the ball valve. The working seal chamber pressure sensor also has high-precision characteristics. The measurement range is determined to be 0-0.5MPa based on the actual pressure range of the working seal chamber, with an accuracy of ±0.05MPa, ensuring accurate monitoring of the working seal chamber pressure. These pressure sensors are firmly installed in the upstream pipeline of the ball valve and the designated position of the working seal chamber using a dedicated pressure sensor mounting bracket to ensure the stable operation of the sensor in complex operating environments. The pressure sensor is connected to the signal acquisition module of the control system via a signal transmission cable.

[0024] Displacement sensor: A laser displacement sensor boasts a measurement accuracy of ±0.1mm and a range of 0-3cm, enabling precise measurement of ball valve displacement. The displacement sensor is mounted on a dedicated mounting bracket on the side of the ball valve body. This ensures that the sensor's measurement axis aligns with the ball valve's displacement, ensuring accurate measurement data. The displacement sensor is also connected to the control system's signal acquisition module via a cable to transmit displacement data.

[0025] The control layer adopts a PLC control system. The PLC is connected to the sensor signal transmission cable of the monitoring module through the input module to collect sensor data in real time; it is connected to the various actuator control cables of the execution layer through the output module to output control instructions.

[0026] The PLC program of the PLC control system adopts three-level dynamic judgment logic (taking unit #1 as an example): Combine Figure 1 As shown, Alarm 1: When unit #1 is in phase adjustment or shutdown, and other units are in phase adjustment or shutdown, the ball valve of unit #1 is fully closed and the upstream pressure is greater than 6.24 MPa, triggering Alarm Signal 1. This alarm condition is set to monitor abnormal increases in pressure upstream of the ball valve under specific unit operating conditions, as such abnormally high pressure may be a potential sign of self-excited vibration. Combine Figure 2As shown, alarm 2: when unit #1 is in phase adjustment or shutdown, and other units are in phase adjustment or shutdown, the ball valve of unit #1 is fully closed, the pressure of the working seal exit chamber of unit #1 is greater than 0.1MPa, or the seal exit switch is actuated, triggering alarm signal 22. This alarm mechanism mainly monitors the relevant parameters and status of the working seal chamber. Abnormal increase in the working seal exit chamber pressure or abnormal actuation of the seal exit switch may be associated with the occurrence of self-excited vibration. Combine Figure 3 As shown, Alarm 3: When Unit 1 is in phase adjustment or shutdown, and other units are in phase adjustment or shutdown, the ball valve of Unit 1 is fully closed, and the combination of upstream pressure and ball valve displacement of Unit 1 exceeds the limit: Alarm Signal 3 is triggered after a 20-second delay when the pressure in the water inlet valve extension section exceeds 6.24 MPa (5.2 MPa is the maximum head pressure of a pumped-storage power plant, and 6.24 MPa is 1.2 times the maximum head pressure) and the ball valve displacement exceeds 3.57 mm. Alternatively, Alarm Signal 3 is triggered after a 20-second delay when the pressure in the water inlet valve extension section exceeds 5.2 MPa and the ball valve displacement exceeds 3.29 mm. Alarm Signal 3 comprehensively considers the combination of two key parameters: upstream pressure and ball valve displacement, more comprehensively capturing the characteristics of self-excited vibration.

[0027] It should be noted that any one of Alarm Signal 1, Alarm Signal 2, and Alarm Signal 3 triggers the self-excited vibration alarm, and the self-excited vibration alarm resets when all three are reset. This multi-dimensional, dynamic alarm determination logic greatly improves the accuracy and reliability of self-excited vibration monitoring.

[0028] The processing and execution methods are as follows: Action execution after self-excitation alarm Composite trigger mechanism: If any signal rising edge is triggered ≥3 times within 20 seconds, it is judged as self-excited vibration Combine Figure 4 As shown, if the pressure of the upstream pressure pipe of the ball valve is greater than 6.24MPa, each time a rising edge of pressure change is detected, the pressure over-limit mark of the upstream pressure pipe of the ball valve is counted +1. When the downstream seal detects the exit signal action (rising edge), the exit mark of the downstream seal of the ball valve is counted +1.

[0029] When the pressure limit mark of the pressure steel pipe upstream of the ball valve and the seal exit mark of the ball valve downstream are greater than 0, the timing starts and the counting mark is cleared after 20 seconds.

[0030] When the pressure limit mark of the upstream pressure pipe of the ball valve and the seal exit mark of the downstream ball valve are greater than 2, the ball valve self-excited vibration start signal is continuously output as 1, that is, after the pressure limit of the upstream pressure pipe of the ball valve is detected, or the seal of the downstream ball valve is exited, if the rising edge of the above signal is triggered 3 times within 20s, it is considered that the ball valve self-excited vibration exists; when the pressure is less than 6.24MPa, and the working seal exit signal is reset, and the 20s delay is met, the ball valve self-excited vibration signal is reset.

[0031] When the ball valve self-excited vibration opening signal output is continuously 1, combined with Figure 5 As shown: S1. First, according to the pre-set plan, quickly start the automatic control process, switch the operating water source, and try to exit the working seal. This is the first measure to deal with self-excited vibration. By changing the working conditions of the working seal, try to eliminate the root cause of the self-excited vibration.

[0032] S2. If the ball valve working seal cannot be withdrawn in step S1, the booster pump is activated in time to increase the pressure in the withdrawal chamber to increase the driving force for the withdrawal of the working seal and enable the working seal to withdraw smoothly.

[0033] S3. If the working seal cannot be exited in step S2, the system will quickly start upstream maintenance seal to prevent the situation from further deteriorating by activating more reliable sealing measures, thus avoiding more serious damage to the equipment due to self-excited vibration.

[0034] If the self-excited oscillation phenomenon cannot be effectively eliminated after the above three steps, open the ball valves of other units in the same water unit and open the units in the direction of the turbine. In this way, the water flow is controlled, the conditions for the formation of self-excited oscillation are broken, and the self-excited oscillation is eliminated.

[0035] Implementation scenario: Unit #1 (volute layer) of a pumped storage power plant is shut down for maintenance.

[0036] 1. Perception layer (monitoring module) installation: Install a tee joint on the pressure pipe of the seal exit cavity downstream of the ball valve and install a pressure transmitter (model: PTX-7000) to monitor the pressure of the working seal exit cavity. Install the displacement sensor (model: LVDT-SG80) on the base of the ball valve body (downstream side), fix the mounting bracket with expansion bolts, and adjust the probe spacing to 5±0.2mm. Complete cable laying: using 4mm 2 Shielded cable is laid from the sensor junction box to the control system of the remote IO#2 cabinet on the turbine level.

[0037] 2. Control layer (monitoring method, processing method, execution method) program deployment: -Implant logic modules in PLC to realize three-level alarm judgment, such as Figures 1 to 3 As shown: IF (#1 ​​unit status = phase adjustment OR shutdown) AND (Other unit status = phase adjustment OR shutdown) AND (ball valve fully closed = TRUE) AND (upstream pressure>6.24MPa) THEN alarm1=TRUE / / Alarm 3 combination threshold IF (Upstream pressure > 6.24 MPa AND Displacement > 3.57 mm) OR (upstream pressure > 5.2 MPa AND displacement > 3.29 mm) THEN Start the 20-second delay timer Configure the signal mutation detection logic: / / Pressure rising edge count IF upstream pressure > 6.24MPa AND rising edge THEN pressure count + 1 / / 3 mutation determinations within 20 seconds IF (Pressure count ≥ 3 OR Seal exit count ≥ 3) AND 20 seconds counting THEN Self-excited vibration action = TRUE 3. Execution layer linkage test: Simulating self-excited vibration conditions: Force upstream pressure signal> 6.24MPa for 10 seconds Forced displacement signal>3.57mm.

[0038] During normal operation of the power plant, the pressure and displacement sensors in the sensing layer continuously collect real-time data on the ball valve's upstream pressure, the working seal chamber pressure, and the ball valve's displacement. These data are transmitted via signal transmission cables to the signal acquisition module in the control layer. The signal acquisition module conditions and converts the data before transmitting it to the PLC control system. The PLC control system analyzes and determines the collected data in real time according to a pre-set three-level dynamic decision logic. Once the trigger conditions for Alarm 1, Alarm 2, or Alarm 3 are met, the corresponding alarm signal is immediately triggered, initiating the self-excited vibration alarm decision process.

[0039] Self-excited vibration determination and handling: When the self-excited vibration alarm signal is triggered, the execution layer determines self-excited vibration according to a composite triggering mechanism. Within 20 seconds, if the pressure on the upstream penstock of the ball valve exceeds 6.24 MPa and a rising edge of pressure change is detected, or if the downstream seal detects the activation of the withdrawal signal (rising edge), the corresponding count flag is incremented. If the count flag exceeds 2, the ball valve is determined to be self-excited, and the ball valve self-excited vibration activation signal is continuously output as 1. At this point, the execution layer immediately implements countermeasures according to the pre-set operation process. First, the PLC automatically controls the valve operation, switches the operating water source, and attempts to withdraw the working seal. If the working seal fails to withdraw, the PLC activates the booster pump to increase the withdrawal chamber pressure. If the working seal still fails to withdraw after the booster pump is activated, the PLC activates the upstream maintenance seal device. If the self-excited oscillation phenomenon persists after these three steps, the PLC uses the ball valve control devices of other units to open the ball valves of other units in the same water unit, opening the units in the direction of the turbine and changing the water flow conditions until the self-excited vibration phenomenon is eliminated. During the entire process, the system continuously monitors the changes in various parameters. When the pressure is less than 6.24MPa, the working seal exit signal is restored, and the 20s delay is met, the self-excited vibration signal of the reset ball valve is issued, and the system returns to normal monitoring status.

[0040] Through the above detailed structural composition and implementation steps, the pumped storage power station ball valve self-excited vibration monitoring and processing system of the present invention can effectively realize the accurate monitoring and rapid processing of self-excited vibration, and ensure the safe and stable operation of the pumped storage power station ball valve and the entire power station system.

[0041] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for monitoring and protecting the self-excited vibration of a ball valve in a pumped storage power station, characterized in that: Including monitoring modules and monitoring methods, The monitoring module includes: A pressure sensor and a displacement sensor, wherein the pressure sensor monitors the upstream pressure of the water valve and the pressure in the working sealing chamber of the water valve, and the displacement sensor monitors the displacement of the water valve body; The monitoring method comprises: Unit 1 is in phase adjustment or shutdown state, and other units are in phase adjustment or shutdown state. When the ball valve of unit 1# is fully closed and the upstream pressure is greater than the pressure threshold 1, alarm signal 1 is triggered; When the ball valve of unit 1# is fully closed and the pressure in the working seal exit chamber is greater than the second pressure threshold, or the seal exit switch is actuated, alarm signal 2 is triggered; When the ball valve of unit 1# is fully closed and the upstream pressure and the displacement of the ball valve exceed the limit combination: when the pressure of the water inlet valve extension section is greater than the pressure threshold 3 and the displacement of the ball valve exceeds the distance threshold 1, the alarm signal 3 is triggered after a delay.

2. The method for monitoring and protecting the self-excited vibration of ball valves in a pumped storage power station according to claim 1, characterized in that: Also includes processing methods: The composite trigger mechanism is that if any signal rising edge is triggered ≥3 times within 20 seconds, it is judged as self-excited vibration. If the pressure of the upstream pressure pipe of the ball valve is greater than the pressure threshold 1, each time a rising edge of pressure change is detected, the pressure limit mark of the upstream pressure pipe of the ball valve is counted up by 1; when the downstream seal detects the exit signal action (rising edge), the exit mark of the downstream seal of the ball valve is counted up by 1; When the pressure limit mark of the upstream pressure steel pipe of the ball valve and the seal exit mark of the downstream ball valve are greater than 2, the ball valve self-excited vibration start signal is continuously output as 1, that is, after the pressure limit of the upstream pressure steel pipe of the ball valve is detected, or the seal exit of the downstream ball valve is detected, if the rising edge of the above signal is triggered 3 times within 20s, it is considered that the ball valve self-excited vibration exists.

3. The method for monitoring and protecting the self-excited vibration of a ball valve in a pumped storage power station according to claim 2, characterized in that: Also includes the execution method: When the ball valve self-excited vibration opening signal output is continuously 1: S1. First, start the automatic control process and switch the operating water source to exit the working seal; S2. If the ball valve working seal cannot be withdrawn in step S1, the booster pump is activated in time to increase the withdrawal chamber pressure to withdraw the working seal; S3. If the working seal still cannot be withdrawn in step S2, quickly start the upstream maintenance seal; S4. If the self-oscillation phenomenon cannot be eliminated after the above steps S1, S2, and S3, the ball valves of other units in the same water unit are opened, and the unit is opened in the turbine direction.

4. The method for monitoring and protecting the self-excited vibration of a ball valve in a pumped storage power station according to claim 2, characterized in that: When the pressure limit mark of the pressure steel pipe upstream of the ball valve and the seal exit mark of the ball valve downstream are greater than 0, the timing starts and the counting mark is cleared after 20 seconds.

5. The method for monitoring and protecting the self-excited vibration of ball valves in a pumped storage power station according to claim 2, characterized in that: When the pressure is less than the pressure threshold 1, and the working seal exit signal is restored, and the 20s delay is met, the self-excited vibration signal of the reset ball valve is turned on.

6. The method for monitoring and protecting the self-excited vibration of a ball valve in a pumped storage power station according to claim 1, characterized in that: Pressure threshold 1 is 1.2 times the maximum head pressure of the pumped storage power plant.

7. The method for monitoring and protecting the self-excited vibration of a ball valve in a pumped storage power station according to claim 1, characterized in that: When the ball valve of unit 1# is fully closed and the upstream pressure and ball valve displacement exceed the limit combination: When the pressure in the extension section of the water inlet valve is greater than 6.24Mpa and the displacement of the ball valve exceeds 3.57mm, the alarm signal will be triggered after a delay of 20s.

8. The method for monitoring and protecting the self-excited vibration of ball valves in a pumped storage power station according to claim 7, characterized in that: Or when the pressure in the extension section of the water inlet valve is greater than 5.2Mpa and the displacement of the ball valve exceeds 3.29mm, the alarm signal will be triggered after a delay of 20s.

9. The method for monitoring and protecting the self-excited vibration of ball valves in a pumped storage power station according to claim 1, characterized in that: The second pressure threshold is 0.1 MPa.

10. The method for monitoring and protecting the self-excited vibration of ball valves in a pumped storage power station according to claim 1, characterized in that: Any trigger alarm signal will trigger the self-excited vibration alarm, and the self-excited vibration alarm will reset when all are reset.

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