Method for eliminating abnormal vibration noise during pumping start of water turbine

Abstract

The invention discloses a method for eliminating abnormal vibration noise during water pumping starting of a water turbine, which is characterized in that three control signals are arranged between an electric speed control cabinet and a monitoring cabinet, and the method comprises the following steps of: when a speed regulator starting and stopping valve starting command is monitored and issued, issuing a speed regulator water pump direction command (pulse) until a guide vane is opened for 2 seconds and then exiting; when the monitoring issues a'water inlet valve opening command 'until a ball valve full-closing signal disappears for 20 seconds, a'guide vane small opening degree input command (pulse)' is issued to the electric speed control cabinet, and the guide vane is opened to 5% small opening degree in advance; after monitoring issuing of a'water pump direction starting-up command ', issuing of a'guide vane small-opening exit command (pulse)' is delayed for 2s, and meanwhile, resetting of a phase modulation command is realized. The method has the advantage that continuous abnormal sound and abnormal vibration occurring when water pumping phase modulation is converted into water pumping can be eliminated.

Description

Technical Field

[0001] The invention relates to the technical field of hydropower stations, in particular to a method for eliminating abnormal vibration noise when a turbine is started for pumping water. Background Art

[0002] There are many working conditions of pump-turbine units, and the working condition runner process is complicated. The process from static state to pumping condition can be divided into two processes, namely, from static state to pumping phase adjustment condition, and from pumping phase adjustment condition to pumping condition.

[0003] 1. Process from static state to pumping phase adjustment

[0004] Pumping phase adjustment is a common working condition of pumped storage units. There are two pumping modes: static frequency converter (SFC) and back-to-back. The SFC mode means that the static frequency converter generates a large torque to drive the unit through a very small current; the back-to-back mode means that one unit drives another unit to pump water, and the speeds of the two units increase at the same time. When the driven unit reaches the pumping phase adjustment condition, the driving unit stops again.

[0005] (1) Before the unit reaches a stationary state, it is necessary to put into operation related auxiliary equipment such as the high-pressure oil jacking system, technical water supply, and bearing cooling system.

[0006] (2) When the unit reaches a stationary state, the pumping direction phase-changing switch is closed, the SFC auxiliary equipment is started, the SFC electrical connection is established, and the unit begins the water pressurization process. The purpose of water pressurization is to make the impeller rotate in the air to reduce the resistance and active power consumption of the unit startup.

[0007] (3) Fully open the upper and lower stop ring water inlet valves; after the water flow of the upper and lower stop rings is normal, open the water pressure valve and fully open the volute to tailwater connecting valve. After the monitoring device receives the tailwater pipe water level low signal, close the water pressure valve; if the tailwater pipe water level high signal is received, open the water pressure replenishment valve for fine adjustment until the tailwater pipe water level low signal is received, and end the water pressure process.

[0008] (4) Start SFC, apply excitation, close the DC demagnetization switch (Fast Cut Back, FCB), and the unit starts to rotate.

[0009] (5) When the unit speed is higher than 450r / min (i.e. 90% of the rated speed Ne), the high-pressure oil jacking system is exited. At this time, when the monitoring device determines that the unit outlet voltage is greater than 90% of the rated voltage, the unit speed is greater than 95% Ne, the high-pressure oil jacking pump stops running, and the SFC synchronization is released, the synchronization device is started; the unit outlet circuit breaker is closed, the SFC output switch is opened, the dragged switch is opened, and the unit is connected to the grid and enters the pumping phase adjustment condition.

[0010] 2. Process from pumping phase adjustment to pumping operation

[0011] (1) After the reactive power of the unit is preset, the water filling process begins. Close the water pressure valve, water pressure air supply valve and the volute to tailwater connecting valve, and open the volute exhaust valve; when the above valves are monitored to operate correctly and reach the first-level splashing power (-22MW), exit the main water inlet valve working seal. At this time, water has already entered the volute.

[0012] (2) When the unit reaches the secondary splash water power (-44MW), close the volute exhaust valve, open the tailwater return exhaust valve and the runner return exhaust valve, and open the main water inlet valve at the same time. When the volute exhaust valve, tailwater return exhaust valve and runner return exhaust valve operate correctly and receive the main water inlet valve micro-opening signal, close the tailwater pipe return exhaust valve, the runner return exhaust valve, the upper and lower leak-proof ring water inlet valves, and the unit is filled with water.

[0013] (3) Reset the governor phase adjustment mode, set the governor to operate in water pump mode, the guide vanes are gradually opened, and the process monitoring guide vanes are not fully closed. The main water inlet valve has reached the fully open position. At this time, the unit reaches the steady state of pumping.

[0014] In the actual work process, the following problems were found:

[0015] The high-head pump turbine has a large runner diameter and high speed, and the centrifugal force at the pump outlet is large, so the pressure-building capacity is strong, and the pressure in the bladeless area is high during pressure-building. At the same time, high-head units are more sensitive to gap flow leakage;

[0016] 1. When the pumping phase is adjusted to pump water, the guide vane may not be closed tightly in theory. The reason for the loose closing may be poor installation quality, insufficient pressure of the governor oil, insufficient pressure stroke of the guide vane servo, high pressure in the runner chamber, etc. The influence of the superimposed jet may cause the guide vane facade to open and close continuously, causing collision, resulting in continuous abnormal noise and vibration;

[0017] 2. When the pumping phase is adjusted and the guide vane is opened very slightly, the servo opening / closing cavity of the servo is in a flat pressure state for a moment after the servo is withdrawn and tightened. At this time, the guide vane is completely affected by the water torque. If the hydraulic design of the guide vane has the design feature of water torque tending to close at a small opening, combined with the influence of the jet, the guide vane will have a sharp twist from tending to open to tending to close, resulting in a violent collision, violent vibration of the water guide mechanism, and abnormal impact sound. Summary of the invention

[0018] The purpose of the present invention is to provide a method for eliminating abnormal vibration noise when a water turbine is pumping water. The present invention has the advantage of being able to eliminate continuous abnormal noise and abnormal vibration that occur when pumping water and adjusting the phase to pump water.

[0019] The technical solution of the present invention is a method for eliminating abnormal vibration noise when a turbine is pumped and started. Three control signals, namely, "speed regulator water pump direction command (pulse)", "guide vane small opening input command (pulse)", and "guide vane small opening exit command (pulse)" are added between the electric control cabinet and the monitoring cabinet by means of communication. The specific process is as follows:

[0020] S1. In the process of pumping phase adjustment, when the monitoring sends the "speed governor start-stop valve start command", it also sends the "speed governor water pump direction command (pulse)", and the "speed governor water pump direction command (pulse)" will exit after the guide vane is opened for 2 seconds;

[0021] S2. In the process of pumping phase adjustment to pumping condition, when the monitoring sends the "water inlet valve opening command" until the ball valve full closing signal disappears 20s later, the electric control cabinet sends the "guide vane small opening input command (pulse)" to open the guide vane to a small opening of 5% in advance;

[0022] S3. After the monitoring sends the "water pump direction start command", it will send the "guide vane small opening exit command" (pulse) after a delay of 2s, and at the same time restore the phase adjustment command.

[0023] In the aforementioned method for eliminating abnormal vibration noise during water turbine pumping start, the given value of the guide vane opening in S1 is -7.

[0024] Compared with the prior art, the present application adds three control signals, namely, "speed regulator water pump direction command", "guide vane small opening input command" and "guide vane small opening exit command" by means of communication between the electric control cabinet and the monitoring cabinet; and issues corresponding instructions at the corresponding time, thereby effectively reducing the vibration degree of the top cover during the pressure building stage, preventing sudden changes in guide vane vibration, avoiding sudden changes in top cover vibration at the moment of opening the guide vane, and reducing guide vane vibration.

[0025] Therefore, the present invention has the advantage of being able to eliminate the continuous abnormal noise and abnormal vibration that occur when the pumping phase is adjusted and the pumping is switched. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a graph of vibration data of the original top cover in an embodiment of the present invention;

[0027] Figure 2 is a graph of top cover vibration data after using the method in an embodiment of the present invention;

[0028] Figure 3 is a diagram of vibration data of the original guide vane in an embodiment of the present invention;

[0029] Figure 4 is a diagram of guide vane vibration data after using the method in an embodiment of the present invention;

[0030] Figure 5 This is a flow chart of SFC pumping of the unit in an embodiment of the present invention;

[0031] Figure 6 It is a flow chart of the unit pumping to pumping phase adjustment in an embodiment of the present invention. DETAILED DESCRIPTION

[0032] The present invention is further described below in conjunction with the accompanying drawings and embodiments, but they are not intended to limit the present invention.

[0033] Embodiment. A method for eliminating abnormal vibration noise when a turbine is pumped and started, wherein three control signals, namely, "speed regulator water pump direction command (pulse)", "guide vane small opening input command (pulse)", and "guide vane small opening exit command (pulse)" are added between the electric control cabinet and the monitoring cabinet by means of communication. The specific process is as follows:

[0034] S1. When the monitoring sends the "speed governor start-stop valve start command", it also sends the "speed governor water pump direction command (pulse)" and the "speed governor water pump direction command (pulse)" will exit after the guide vane is opened for 2 seconds;

[0035] S2. In the process of pumping phase adjustment to pumping condition, when the monitoring sends the "water inlet valve opening command" until the ball valve full closing signal disappears 20s later, the "guide vane small opening input command (pulse)" is sent to the electric control cabinet to open the guide vane to a small opening of 5% in advance; this can effectively avoid the situation that the relay opening / closing cavity is in a flat pressure state for a moment when the guide vane is extremely small when the pumping phase adjustment is turned into pumping, which causes intense vibration of the water guide mechanism and abnormal impact sound;

[0036] S3. After the monitoring sends the "water pump direction start command", it will send the "guide vane small opening exit command (pulse)" with a delay of 2s, and at the same time restore the phase adjustment command.

[0037] The guide vane opening setting value in S1 is -7, which can keep the guide vane in a tightened state.

[0038] Figure 5 and 6 This is the flow chart of Unit 4. The "speed governor start-stop valve start command" of Tianchi Power Station is issued simultaneously when the unit reaches a stationary state and the pumping direction phase-changing switch is closed.

[0039] The guide vane closed-loop control calculates the deviation between the given value and the feedback value and then outputs a command. When the deviation is positive, the guide vane is operated to move in the open direction, and when the deviation is negative, the guide vane is operated to move in the closing direction. The larger the deviation, the larger the command, which can eliminate the situation where the guide vane is theoretically closed but not actually closed tightly.

[0040] The pressure-generating power in the phase-adjusting pumping process needs to be determined on-site through a real machine splashing power test.

[0041] Effect verification

[0042] By obtaining the vibration data of the top cover and the guide vane under the same conditions before and after the application of this method, the vibration of the top cover is compared. Figure 1 and 2 , the guide vane vibration is as follows Figure 3 and 4 ;

[0043] from Figure 1 and Figure 2 , Figure 3 and Figure 4 It can be clearly seen from the comparison that the application of this method significantly reduces the vibration of the top cover in the post-compression stage and the vibration of the guide vane has no sudden change. There is no sudden change in the vibration of the top cover at the moment of opening the guide vane and the vibration of the guide vane is reduced.

[0044] This shows that this method is practicable and effective.

Claims

1. A method for eliminating abnormal vibration noise during water turbine pumping start, characterized in that: The three control signals of "speed regulator water pump direction command (pulse)", "guide vane small opening input command (pulse)" and "guide vane small opening exit command (pulse)" are added between the electric control cabinet and the monitoring cabinet by means of communication. The specific process is as follows: S1. In the process of pumping phase adjustment, when the monitoring sends the "speed governor start-stop valve start command", it also sends the "speed governor water pump direction command (pulse)", and the "speed governor water pump direction command (pulse)" will exit after the guide vane is opened for 2 seconds; S2. In the process of pumping phase adjustment to pumping condition, when the monitoring sends the "water inlet valve opening command", the signal of ball valve full closing disappears for 20 seconds, and then the "guide vane small opening input command (pulse)" is sent to the electric control cabinet to open the guide vane to a small opening of 5% in advance; S3. After the monitoring sends the "water pump direction start command", it will send the "guide vane small opening exit command (pulse)" with a delay of 2s, and at the same time restore the phase adjustment command.

2. A method for eliminating abnormal vibration noise during water turbine pumping start according to claim 1, characterized in that: The given value of the guide vane opening in S1 is -7.

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