Method for automatically eliminating hydraulic self-oscillation of water inlet ball valve of pumped storage power station

Abstract

A method for automatically eliminating hydraulic self-excited oscillation of a water inlet ball valve of a pumped storage power station sequentially comprises the steps of analyzing reasons for generating self-excited oscillation of the ball valve, analyzing the characteristics of the hydraulic self-excited oscillation of the ball valve, and designing and executing a program for automatically eliminating the hydraulic self-excited oscillation of the ball valve. After a monitoring system receives a hydraulic self-oscillation action signal of the ball valve, an elimination process is automatically started; in addition, the program further has a mode for manual selection to eliminate the hydraulic self-excited oscillation, each elimination process also has an independent switching function, an operator has more selection space when eliminating the hydraulic self-excited oscillation of the ball valve, and faults can be eliminated faster and better.

Description

Technical Field

[0001] The invention belongs to the technical field of operation of a pumped storage power station and relates to a method for automatically eliminating hydraulic self-excited oscillation of a water inlet ball valve of a pumped storage power station. Background Art

[0002] Pumped storage power stations usually undertake peak load regulation, frequency regulation, phase regulation and emergency standby tasks in power systems. Pumped storage power stations are mainly composed of an upper reservoir, a lower reservoir, underground plant equipment (including units and ball valves), etc. In general, multiple units pass through a pressure steel pipe from the inlet / outlet gate of the upper reservoir, connecting the ball valve and the unit, and finally discharge to the lower reservoir through the inlet / outlet of the lower reservoir. The function of the ball valve in normal operation is to open and close the water flow and serve as a water retaining device during plant maintenance; there are two seals, the upstream side is the maintenance seal, and the downstream side is the working seal; the water for the two seals is generally taken from the upstream pressure steel pipe. When the unit is started and stopped normally, only the working seal is put into and withdrawn.

[0003] In recent years, some pumped storage power stations have experienced self-excited vibrations caused by loose ball valve seals. The maximum pressure pulsation of the pressure steel pipe caused by the self-excited vibration can reach twice the static pressure upstream of the ball valve, which is extremely harmful and may cause serious accidents such as pipe bursts and flooding of power plants, seriously threatening the safe operation of power station units. In response to this problem, the general accident handling methods and processes of the operators of various pumped storage power stations are as follows: Handling of ball valve hydraulic self-excited oscillations, (1) Notify the on-site duty personnel to cut off the water inlet pipeline of the ball valve working seal injection chamber and close the ball valve working seal water inlet valve.

[0004] (2) Notify the on-site duty personnel to open the ball valve working bypass valve and manually open the guide vane of the unit on site.

[0005] (3) If circumstances permit, the host computer manually starts the turbine of another standby unit of the same water supply pipe.

[0006] (4) Notify the on-site duty personnel to manually start the ball valve to inspect the seal.

[0007] (5) Notify the standby personnel to go to the upper reservoir and urgently lower the inlet and outlet gates of the upper reservoir.

[0008] In summary, after the ball valve self-oscillates, the on-site duty personnel need to eliminate the hydraulic self-oscillation of the ball valve through various manual intervention methods. This method that relies solely on manual analysis, judgment and processing not only requires a high level of technical level and experience of the operating personnel, but also has safety risks caused by inadequate or misoperation of the human operator. Moreover, if a large amount of water leaks from the pressure steel pipe or ball valve during the on-site manual handling process, there is also a great risk to the life safety of the handling personnel. Summary of the invention

[0009] The technical problem to be solved by the present invention is to provide a method for automatically eliminating the hydraulic self-excited oscillation of the water inlet ball valve of a pumped storage power station. By analyzing the causes and characteristics of the hydraulic self-excited oscillation of the ball valve, the self-excited oscillation of the ball valve caused by water leakage from the working seal is automatically eliminated.

[0010] In order to solve the above technical problems, the technical solution adopted by the present invention is: a method for automatically eliminating the hydraulic self-excited oscillation of the water inlet ball valve of a pumped storage power station, comprising the following steps: S1, analyze the reasons why the ball valve produces self-excited oscillation; S2, analyze the characteristics of the hydraulic self-excited oscillation of the ball valve; S3, program design for automatic elimination of hydraulic self-excited oscillation of ball valve; S4, execution. After the monitoring system receives the hydraulic self-excited oscillation action signal of the ball valve, the system automatically exits the peristaltic device of the unit, exits the mechanical brake, puts the high-top pump into operation, and prompts you to select the manual or automatic disposal mode. If the manual mode is selected, you will manually select which measures to take for disposal. If the automatic mode is selected, the following steps will be executed: S4-1, the monitoring system issues a command to open the bypass valve of the ball valve. After a certain delay after the bypass valve is opened, the monitoring system monitors whether the hydraulic self-excited oscillation alarm signal of the ball valve has been restored; if the hydraulic self-excited oscillation alarm of the ball valve has been restored, the command to start the hydraulic self-excited oscillation process of the ball valve is restored; S4-2, after the ball valve working seal is put into operation again, if the self-excited oscillation alarm is still not eliminated, a signal is issued to open the drainage solenoid valve of the ball valve working seal exit chamber, and the ball valve working seal exit chamber is directly drained to observe the operation of the ball valve working seal; if the ball valve hydraulic self-excited oscillation alarm has been reset, the ball valve hydraulic self-excited oscillation process start command is reset; S4-3, after opening the drain solenoid valve of the ball valve working seal exit chamber, if the self-excited oscillation alarm is still not eliminated, a command is issued to open the ball valve working bypass valve of the adjacent unit in the same flow channel; if the ball valve hydraulic self-excited oscillation alarm has been reset, the ball valve hydraulic self-excited oscillation process start command is reset; S4-4, after opening the ball valve working bypass valve of the adjacent unit in the same flow channel, if the self-excited oscillation alarm is still not eliminated, then a start-up command for the turbine direction of the adjacent unit in the same flow channel is issued. If the ball valve hydraulic self-excited oscillation alarm has been reset, then the ball valve hydraulic self-excited oscillation process start command is reset; S4-5, after starting the turbine direction of the adjacent unit in the same flow channel, if the self-excited oscillation alarm is still not eliminated, a command to lower the inlet and outlet gates of the upper reservoir will be issued, and the unit will not be able to standby or operate normally afterwards; as long as the gate of the upper reservoir can be lowered normally, the hydraulic self-excited oscillation of the ball valve will quickly disappear.

[0011] In S3, after the monitoring system receives the hydraulic self-excited oscillation action signal of the ball valve, the elimination process will be automatically started; the program also has a mode for manually selecting which method to eliminate, and each elimination process also has a separate start and stop function.

[0012] In S3, the logic design for automatically eliminating the hydraulic self-excited oscillation of the ball valve is as follows: in automatic mode, the process will decide whether to continue to the next step based on the feedback of each step, and execute it in the set order to the end; in manual mode, a command is manually issued to execute a certain step, and the feedback after execution is accepted, but other steps will no longer be executed.

[0013] In S3, a functional on / off switch is set for each step of the disposal process. When the step is set to the exit position, the logic will automatically skip this step and execute the next step in automatic mode, while it will not be affected in manual mode. When the step is set to the on position, the automatic mode will execute this step and determine whether to continue to execute it automatically based on the execution feedback. In manual mode, a command is issued to execute this step, only this step is executed, and feedback after execution is accepted, but other steps will no longer be executed.

[0014] In S4, the following steps are also included: S4A-1, the monitoring system determines that the hydraulic self-excited oscillation of the ball valve has indeed occurred, and sends out a hydraulic self-excited oscillation action signal of the ball valve; S4A-2, according to the selected automatic or manual mode, eliminate self-oscillation. In the automatic mode, if the function selection switch of a step is in the "exit" state, the step will not be executed and the next step in the "on" state will be automatically executed; S4A-3, if manual mode is selected, manually send a command to a specific program to check whether the execution and feedback are normal; S4A-4, if the automatic mode is selected, the monitoring system starts the process of automatically eliminating the hydraulic self-excited oscillation of the ball valve, and executes in sequence the opening of the ball valve bypass valve, the insertion of the ball valve working seal, the opening of the ball valve working seal exit chamber drainage solenoid valve, the opening of the ball valve working bypass valve of the adjacent unit in the same flow channel, the start-up of the turbine direction of the adjacent unit in the same flow channel, and the release of the reservoir inlet and outlet gate command; after each step is executed, it will be judged whether the self-excited oscillation has been eliminated. If it has been eliminated, the process will be exited; if it has not been eliminated, the next step will be executed, and the purpose of automatically eliminating the hydraulic self-excited oscillation of the ball valve will be finally achieved.

[0015] The main beneficial effects of the present invention are: By setting up an automatic elimination process for the hydraulic self-excited oscillation phenomenon of the ball valve through the monitoring system, the treatment plan can be automatically executed faster and more orderly, or a certain elimination process can be manually selected to eliminate the fault, reducing the risk of on-site operating errors caused by operator tension or lack of experience.

[0016] By setting up an automatic elimination process for the hydraulic self-oscillation of the ball valve through the monitoring system, the operating personnel do not need to rush to the site for emergency disposal at the first time. If the hydraulic self-oscillation of the ball valve causes large-scale leakage of the pressure steel pipe or the ball valve, the life safety of the operating personnel can be better guaranteed through program processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0018] Figure 1 It is a flow chart of the present invention. DETAILED DESCRIPTION

[0019] like Figure 1 A method for automatically eliminating hydraulic self-excited oscillation of a water inlet ball valve of a pumped storage power station comprises the following steps: S1, analyze the reasons why the ball valve produces self-excited oscillation; S2, analyze the characteristics of the hydraulic self-excited oscillation of the ball valve; S3, program design for automatic elimination of hydraulic self-excited oscillation of ball valve; S4, execution. After the monitoring system receives the hydraulic self-excited oscillation action signal of the ball valve, the system automatically exits the peristaltic device of the unit, exits the mechanical brake, puts the high-top pump into operation, and prompts you to select the manual or automatic disposal mode. If the manual mode is selected, you will manually select which measures to take for disposal. If the automatic mode is selected, the following steps will be executed: S4-1, the monitoring system issues a command to open the bypass valve of the ball valve. After a certain delay after the bypass valve is opened, the monitoring system monitors whether the hydraulic self-excited oscillation alarm signal of the ball valve has been restored; if the hydraulic self-excited oscillation alarm of the ball valve has been restored, the command to start the hydraulic self-excited oscillation process of the ball valve is restored; S4-2, after the ball valve working seal is put into operation again, if the self-excited oscillation alarm is still not eliminated, a signal is issued to open the drainage solenoid valve of the ball valve working seal exit chamber, and the ball valve working seal exit chamber is directly drained to observe the operation of the ball valve working seal; if the ball valve hydraulic self-excited oscillation alarm has been reset, the ball valve hydraulic self-excited oscillation process start command is reset; S4-3, after opening the drain solenoid valve of the ball valve working seal exit chamber, if the self-excited oscillation alarm is still not eliminated, a command is issued to open the ball valve working bypass valve of the adjacent unit in the same flow channel; if the ball valve hydraulic self-excited oscillation alarm has been reset, the ball valve hydraulic self-excited oscillation process start command is reset; S4-4, after opening the ball valve working bypass valve of the adjacent unit in the same flow channel, if the self-excited oscillation alarm is still not eliminated, then a start-up command for the turbine direction of the adjacent unit in the same flow channel is issued. If the ball valve hydraulic self-excited oscillation alarm has been reset, then the ball valve hydraulic self-excited oscillation process start command is reset; S4-5, after starting the turbine direction of the adjacent unit in the same flow channel, if the self-excited oscillation alarm is still not eliminated, a command to lower the inlet and outlet gates of the upper reservoir will be issued, and the unit will not be able to standby or operate normally afterwards; as long as the gate of the upper reservoir can be lowered normally, the hydraulic self-excited oscillation of the ball valve will quickly disappear.

[0020] In the preferred solution, in S3, after the monitoring system receives the hydraulic self-excited oscillation action signal of the ball valve, the elimination process will be automatically started; the program also has a mode for manually selecting which method to eliminate, and each elimination process also has a separate start and stop function.

[0021] In the preferred solution, in S3, the logic design for automatically eliminating the hydraulic self-excited oscillation of the ball valve is: in the automatic mode, the process will decide whether to continue to execute the next step according to the feedback of each step, and execute it in the set order to the end; in the manual mode, a command is manually issued to execute a certain step, and the feedback after execution is accepted, but other steps will no longer be executed.

[0022] In the preferred scheme, in S3, a functional on / off switch is set for each step of the disposal process. When the step is set in the exit position, the logic will automatically skip this step and execute the next step in the automatic mode, and it will not be affected in the manual mode; when the step is set in the engagement position, the automatic mode will execute this step and determine whether to continue to execute automatically based on the execution feedback. In the manual mode, a command is issued to execute this step, only this step is executed, and feedback after execution is accepted, but other steps will no longer be executed.

[0023] In a preferred solution, in S4, the following steps are also included: S4A-1, the monitoring system determines that the hydraulic self-excited oscillation of the ball valve has indeed occurred, and sends out a hydraulic self-excited oscillation action signal of the ball valve; S4A-2, according to the selected automatic or manual mode, eliminate self-oscillation. In the automatic mode, if the function selection switch of a step is in the "exit" state, the step will not be executed and the next step in the "on" state will be automatically executed; S4A-3, if manual mode is selected, manually send a command to a specific program to check whether the execution and feedback are normal; S4A-4, if the automatic mode is selected, the monitoring system starts the process of automatically eliminating the hydraulic self-excited oscillation of the ball valve, and executes in sequence the opening of the ball valve bypass valve, the insertion of the ball valve working seal, the opening of the ball valve working seal exit chamber drainage solenoid valve, the opening of the ball valve working bypass valve of the adjacent unit in the same flow channel, the start-up of the turbine direction of the adjacent unit in the same flow channel, and the release of the reservoir inlet and outlet gate command; after each step is executed, it will be judged whether the self-excited oscillation has been eliminated. If it has been eliminated, the process will be exited; if it has not been eliminated, the next step will be executed, and the purpose of automatically eliminating the hydraulic self-excited oscillation of the ball valve will be finally achieved.

[0024] Embodiment 1, Analysis of the causes of self-excited oscillation of the ball valve: The inner surface of the aluminum bronze fixed outer ring of the ball valve working seal has dents along the water flow, which leads to leakage on the sealing surface. This is the reason for the leakage between the two chambers of the working seal and the valve body. The water pressure of the seal is damaged, causing the working seal to be in a critical state. The system disturbance causes the working seal to be repeatedly thrown in and out, causing the ball valve working seal to leak and produce hydraulic self-excited vibration.

[0025] When the pressure acting on the working seal drops to a certain critical value, the working seal sliding ring will open slightly, resulting in a small amount of water leakage. At this time, just a little disturbance can generate a very small positive pressure pulse in the pressure pipe, causing the working seal sliding ring to tend to close. The reduction in water leakage increases the pressure wave transmitted to the pressure pipe.

[0026] After one and a half cycles, the pressure wave reflected from the upper reservoir end turns into a negative pressure wave at the ball valve. This lower pressure causes the working seal sliding ring to open again, increasing the leakage and the negative pressure. After the next half cycle, the low pressure is reflected back from the reservoir and becomes high pressure again, prompting the working seal sliding ring to close and reducing the leakage. This cycle repeats and finally reaches a certain state where the pressure on the working seal dynamic ring is low for a while and becomes very high at a later time, thus creating the conditions for self-excited vibration.

[0027] However, due to long-term cavitation erosion, there is serious leakage between the "exit" cavity and the "input" cavity of the ball valve working seal, and between the "exit" cavity and the ball valve body, causing the two cavities to tend to be evenly pressurized, causing the working seal sliding ring to be compressed in a critical state of action, and the system disturbance causes the working seal to be repeatedly invested and withdrawn, causing the ball valve working seal to leak and resulting in hydraulic self-excited vibration.

[0028] Embodiment 2, Analysis of the characteristics of ball valve hydraulic self-excited oscillation: The ball valve working seal throw and retraction signals of the monitoring system are frequently activated; The monitoring system reported that the pressure steel pipe before and after the ball valve had a high pressure alarm signal, which was shaking, and pressure pulsation occurred; The displacement signal data of the ball valve in the monitoring system becomes significantly larger; The pressure difference between the input chamber and the exit chamber of the ball valve working seal of the monitoring system is significantly reduced; The ball valve on site vibrates greatly, and the working seal makes frequent impact sounds when it is thrown in and out; There is a noticeable sense of vibration in the upper reservoir.

[0029] The above-mentioned embodiments are only preferred technical solutions of the present invention and should not be regarded as limitations of the present invention. The embodiments and features in the embodiments of the present application can be arbitrarily combined with each other without conflict. The protection scope of the present invention shall be the technical solutions recorded in the claims, including the equivalent replacement solutions of the technical features in the technical solutions recorded in the claims. That is, equivalent replacement improvements within this scope are also within the protection scope of the present invention.

Claims

1. A method for automatically eliminating the hydraulic self-excited oscillation of the water inlet ball valve of a pumped storage power station, characterized by: comprising: Follow these steps: S1, analyze the reasons why the ball valve produces self-excited oscillation; S2, analyze the characteristics of the hydraulic self-excited oscillation of the ball valve; S3, program design for automatic elimination of hydraulic self-excited oscillation of ball valve; S4, execution. After the monitoring system receives the hydraulic self-excited oscillation action signal of the ball valve, the system automatically exits the peristaltic device of the unit, exits the mechanical brake, puts the high-top pump into operation, and prompts you to select the manual or automatic disposal mode. If the manual mode is selected, you will manually select which measures to take for disposal. If the automatic mode is selected, the following steps will be executed: S4-1, the monitoring system issues a command to open the bypass valve of the ball valve. After a certain delay after the bypass valve is opened, the monitoring system monitors whether the hydraulic self-excited oscillation alarm signal of the ball valve has been restored; if the hydraulic self-excited oscillation alarm of the ball valve has been restored, the command to start the hydraulic self-excited oscillation process of the ball valve is restored; S4-2, after the ball valve working seal is put into operation again, if the self-excited oscillation alarm is still not eliminated, a signal is issued to open the drainage solenoid valve of the ball valve working seal exit chamber, and the ball valve working seal exit chamber is directly drained to observe the operation of the ball valve working seal; if the ball valve hydraulic self-excited oscillation alarm has been reset, the ball valve hydraulic self-excited oscillation process start command is reset; S4-3, after opening the drain solenoid valve of the ball valve working seal exit chamber, if the self-excited oscillation alarm is still not eliminated, a command is issued to open the ball valve working bypass valve of the adjacent unit in the same flow channel; if the ball valve hydraulic self-excited oscillation alarm has been reset, the ball valve hydraulic self-excited oscillation process start command is reset; S4-4, after opening the ball valve working bypass valve of the adjacent unit in the same flow channel, if the self-excited oscillation alarm is still not eliminated, then a start-up command for the turbine direction of the adjacent unit in the same flow channel is issued. If the ball valve hydraulic self-excited oscillation alarm has been reset, then the ball valve hydraulic self-excited oscillation process start command is reset; S4-5, after starting the turbine direction of the adjacent unit in the same flow channel, if the self-excited oscillation alarm is still not eliminated, a command to lower the inlet and outlet gates of the upper reservoir will be issued, and the unit will not be able to standby or operate normally afterwards; as long as the gate of the upper reservoir can be lowered normally, the hydraulic self-excited oscillation of the ball valve will quickly disappear.

2. The method for automatically eliminating the hydraulic self-excited oscillation of the water inlet ball valve of a pumped storage power station according to claim 1 is characterized by: In S3, after the monitoring system receives the hydraulic self-excited oscillation action signal of the ball valve, the elimination process will be automatically started; the program also has a mode for manually selecting which method to eliminate, and each elimination process also has a separate start and stop function.

3. The method for automatically eliminating the hydraulic self-excited oscillation of the water inlet ball valve of a pumped storage power station according to claim 2 is characterized by: In S3, the logic design for automatically eliminating the hydraulic self-excited oscillation of the ball valve is as follows: in automatic mode, the process will decide whether to continue to the next step based on the feedback of each step, and execute it in the set order to the end; in manual mode, a command is manually issued to execute a certain step, and the feedback after execution is accepted, but other steps will no longer be executed.

4. The method for automatically eliminating the hydraulic self-excited oscillation of the water inlet ball valve of a pumped storage power station according to claim 3 is characterized by: In S3, a functional on / off switch is set for each step of the disposal process. When the step is set to the exit position, the logic will automatically skip this step and execute the next step in automatic mode, while it will not be affected in manual mode. When the step is set to the on position, the automatic mode will execute this step and determine whether to continue to execute it automatically based on the execution feedback. In manual mode, a command is issued to execute this step, only this step is executed, and feedback after execution is accepted, but other steps will no longer be executed.

5. The method for automatically eliminating the hydraulic self-excited oscillation of the water inlet ball valve of a pumped storage power station according to claim 1 is characterized by: In S4, the following steps are also included: S4A-1, the monitoring system determines that the hydraulic self-excited oscillation of the ball valve has indeed occurred, and sends out a hydraulic self-excited oscillation action signal of the ball valve; S4A-2, according to the selected automatic or manual mode, eliminate self-oscillation. In the automatic mode, if the function selection switch of a step is in the "exit" state, the step will not be executed and the next step in the "on" state will be automatically executed; S4A-3, if manual mode is selected, manually send a command to a specific program to check whether the execution and feedback are normal; S4A-4, if the automatic mode is selected, the monitoring system starts the process of automatically eliminating the hydraulic self-excited oscillation of the ball valve, and executes in sequence the opening of the ball valve bypass valve, the insertion of the ball valve working seal, the opening of the ball valve working seal exit chamber drainage solenoid valve, the opening of the ball valve working bypass valve of the adjacent unit in the same flow channel, the start-up of the turbine direction of the adjacent unit in the same flow channel, and the release of the reservoir inlet and outlet gate command; after each step is executed, it will be judged whether the self-excited oscillation has been eliminated. If it has been eliminated, the process will be exited; if it has not been eliminated, the next step will be executed, and the purpose of automatically eliminating the hydraulic self-excited oscillation of the ball valve will be finally achieved.

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