Generator sealing oil pump vibration suppression method and generator sealing oil system

Abstract

The generator sealing oil pump vibration suppression method comprises the steps that S1, the vacuum pressure of a sealing oil tank is adjusted in a staged mode, and the vacuum pressure of the sealing oil tank is adjusted to target vacuum pressure from normal pressure in a staged mode; s2, performing vibration vacuum linkage feedback; s3, the net positive suction head is dynamically compensated, the effective net positive suction head of the sealing oil pump is calculated in real time, and when the difference between the effective net positive suction head of the sealing oil pump and the necessary net positive suction head is smaller than the safety allowance, the liquid level of the sealing oil tank is gradually increased according to the preset lifting height or the circulating flow of the sealing oil is gradually reduced according to the preset flow decrement; and S4, adding a defoaming agent. According to the vibration suppression method for the sealed oil pump of the generator, all the steps have a synergistic effect, through a staged adjustment mode, the phenomenon of gas burst release of the sealed oil tank can be reduced, foam of the sealed oil tank is reduced, the possibility of cavitation of the sealed oil pump is reduced, and therefore vibration of the sealed oil pump is reduced. The invention further discloses a generator sealing oil system.

Description

Technical Field

[0001] The present application relates to the technical field of generator sealing oil, and more specifically, to a method for suppressing vibration of a generator sealing oil pump and a generator sealing oil system. Background Art

[0002] Hydrogen is widely used in cooling large generators above 200MW in power generation enterprises. In order to prevent hydrogen leakage inside the generator, the generator system uses sealing oil as the sealing medium. Its function is to prevent hydrogen leakage from inside the generator along the dynamic and static gaps between the generator rotor and the generator stator by providing lubricating oil to the generator shaft end. The sealing oil system can also prevent the atmosphere and gas in the sealing oil from contaminating the hydrogen in the generator. The oil supply for the single-flow ring sealing pad comes from the lubricating oil of the turbine bearing, which is called sealing oil according to its purpose. The sealing oil system is dedicated to supplying oil to the generator sealing pad, and the oil pressure is higher than the hydrogen pressure (gas pressure) inside the generator by a certain amount to prevent hydrogen leakage from the generator along the gap between the rotating shaft and the sealing pad, and also to prevent excessive oil pressure from causing a large amount of oil to enter the generator.

[0003] In the existing sealing oil system, when the vacuum degree of the vacuum oil tank is increased, the dissolved gas is rapidly precipitated to form a gas-liquid two-phase flow, which causes the sealing oil pump to vibrate more (vibration speed ≥ 6 mm / s), and foam accumulation causes the liquid level to be artificially high. The traditional method is difficult to balance the degassing efficiency and equipment stability by simply adjusting the vacuum pressure.

[0004] Therefore, how to suppress the vibration of the sealing oil pump and ensure the normal operation of the generator has become a technical problem that needs to be solved urgently by those skilled in the art. Summary of the invention

[0005] In view of this, the purpose of the present application is to provide a method for suppressing the vibration of a sealing oil pump, so as to suppress the vibration of the sealing oil pump and ensure the normal operation of the generator.

[0006] Another core of the present application is to disclose a generator sealing oil system for use in the above-mentioned sealing oil pump vibration suppression method.

[0007] To achieve the above objectives, this application provides the following technical solutions:

[0008] A method for suppressing vibration of a generator sealing oil pump comprises the following steps:

[0009] Step S1, adjusting the vacuum pressure of the sealed oil tank in stages, adjusting the vacuum pressure of the sealed oil tank in stages from normal pressure to a target vacuum pressure;

[0010] Step S2, Vibration-Vacuum Linkage Feedback: Adjust the opening of the first regulating valve located between the seal oil tank and the vacuum pump or the frequency of the vacuum pump according to the vibration speed of the seal oil pump, so that the vibration speed of the seal oil pump is within the vibration threshold range;

[0011] Step S3, Dynamic Compensation of Net Positive Suction Head (NPSH): Calculate the effective NPSH of the seal oil pump in real time. When the difference between the effective NPSH and the required NPSH of the seal oil pump is less than the safety margin, gradually increase the liquid level of the seal oil tank according to a preset lifting height or gradually reduce the circulation flow rate of the seal oil according to a preset flow rate reduction;

[0012] Step S4, Adding Defoamer: Based on the foam thickness and gas content in the seal oil tank, the defoamer adding component adds defoamer into the seal oil tank.

[0013] Optionally, in the above method for suppressing the vibration of the generator seal oil pump, the step of controlling the vacuum pressure of the seal oil tank in stages specifically includes:

[0014] Step S11, Quick Degassing: By adjusting the opening of the first regulating valve or the frequency of the vacuum pump, reduce the vacuum pressure of the seal oil tank from atmospheric pressure to the first preset vacuum pressure at the first preset gradient rate;

[0015] Step S12, Deep Degassing: Maintain the first preset vacuum pressure for the first preset time, and then adjust the opening of the first regulating valve or the frequency of the vacuum pump to make the vacuum pressure of the seal oil tank drop to the second preset vacuum pressure at the second preset gradient rate;

[0016] Step S13, Steady-State Operation: If the vibration speed of the seal oil pump exceeds the vibration threshold, gradually adjust the second preset vacuum pressure according to a preset pressure increment.

[0017] Optionally, in the above method for suppressing the vibration of the generator seal oil pump, the first preset gradient rate is 7 kPa / 10 minutes, and the first preset vacuum pressure is 20 kPa; and / or,

[0018] The second preset gradient rate is 1 kPa / 20 minutes; and / or,

[0019] The range of the second preset vacuum pressure is 8 kPa - 10 kPa.

[0020] Optionally, in the above method for suppressing the vibration of the generator seal oil pump, in the vibration-vacuum linkage feedback step, the opening of the first regulating valve = the first coefficient × the vibration amplitude of the seal oil pump within the second preset time + the second coefficient × the cumulative vibration amplitude of the seal oil pump within the second preset time.

[0021] Optionally, in the above-mentioned generator sealing oil pump vibration suppression method, in the step of dynamically compensating the cavitation margin, the liquid level value of the sealing oil tank is adjusted by adjusting the opening of a second regulating valve on the oil replenishment pipeline connecting the oil replenishment tank and the sealing oil tank; and / or,

[0022] By adjusting the flow of the sealing oil return pipeline connected in parallel with the sealing oil pump, part of the sealing oil flowing through the sealing oil pump is returned to the sealing oil tank to adjust the liquid level of the sealing oil tank.

[0023] Optionally, in the above-mentioned generator sealing oil pump vibration suppression method, the foam thickness of the sealing oil tank is measured by a foam thickness detection element, and the air content of the sealing oil tank is measured by an air content detection element.

[0024] Optionally, in the above-mentioned generator sealing oil pump vibration suppression method, in the defoaming agent adding step, the content of defoaming agent added to the sealing oil tank by the defoaming agent adding component is calculated according to the following formula: defoaming agent content = third coefficient × (foam thickness - 50) + fourth coefficient × (air content - 1%).

[0025] A generator sealing oil system, used in the above-mentioned generator sealing oil pump vibration suppression method, comprising:

[0026] A sealed oil tank, wherein the sealed oil tank is provided with a liquid level detection element, a vacuum detection element, a foam thickness detection element and an air content detection element, and the sealed oil tank is connected to the oil replenishment tank through an oil replenishment pipeline, and a second regulating valve is provided on the oil replenishment pipeline;

[0027] A sealing oil pump, which is connected to the sealing oil tank and is used to transport the sealing oil in the sealing oil tank to the generator. The sealing oil pump is provided with a vibration detection element;

[0028] A vacuum pump is connected to the sealing oil tank and is used to evacuate the sealing oil tank. A first regulating valve is provided between the sealing oil tank and the vacuum pump. The vacuum pump is connected to the exhaust system.

[0029] A defoaming agent adding component is connected to the sealing oil tank;

[0030] The control component, the liquid level detection element, the vacuum detection element, the foam thickness detection element, the gas content detection element, the first regulating valve, the vibration detection element, the vacuum pump, the first regulating valve and the defoaming agent adding component are all connected to the control component.

[0031] Optionally, the above-mentioned generator sealing oil system also includes a sealing oil return pipeline, which is connected to the sealing oil tank. A return valve is arranged on the sealing oil return pipeline. A flow detection element is arranged downstream of the sealing oil return pipeline. The flow detection element and the return valve are both connected to the control component.

[0032] Optionally, in the above generator seal oil system, a return oil tank is further included. The return oil tank is connected to the generator and is used to collect the seal oil discharged from the generator. The return oil tank is communicated with an expansion oil tank, the expansion oil tank is communicated with an air extraction assembly and a make-up oil tank, and the make-up oil tank is communicated with the seal oil tank.

[0033] As can be seen from the above solution, the method for suppressing the vibration of the generator seal oil pump disclosed in this application can reduce the occurrence of gas explosion release in the seal oil tank and mitigate the vibration of the seal oil pump by adjusting the vacuum pressure of the seal oil tank in stages; by obtaining the vibration speed of the seal oil pump and feedback-adjusting the opening of the first regulating valve or adjusting the frequency of the vacuum pump, the vibration speed of the seal oil pump can be made within the vibration threshold; by dynamically compensating the net positive suction head, cavitation of the seal oil pump can be avoided and the occurrence of vibration of the seal oil pump can be mitigated; the addition of the defoaming agent can reduce the foam in the seal oil tank and reduce the occurrence of false high liquid level. In the method for suppressing the vibration of the generator seal oil pump disclosed in this application, each step acts synergistically. Through the staged adjustment method, the occurrence of gas explosion release in the seal oil tank can be reduced, the foam in the seal oil tank can be reduced, and the possibility of cavitation of the seal oil pump can be mitigated, thereby reducing the vibration of the seal oil pump, ensuring the stability of the system, and ensuring the normal operation of the generator. The generator seal oil system disclosed in this application has the same technical effects as the method for suppressing the vibration of the generator seal oil pump, and will not be elaborated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0035] Figure 1 It is a schematic diagram of the generator seal oil system disclosed in the embodiment of the present application;

[0036] Figure 2 It is a flowchart of the method for suppressing the vibration of the generator seal oil pump disclosed in the embodiment of the present application;

[0037] Figure 3 It is a flowchart of controlling the vacuum pressure of the seal oil tank in stages disclosed in the embodiment of the present application;

[0038] Figure 4 It is a dynamic response curve graph of the vacuum pressure and the vibration speed disclosed in the embodiment of the present application.

[0039] Among them, 10 is a sealed oil tank, 11 is a liquid level detection element, 20 is a sealed oil pump, 30 is a vacuum pump, 31 is a first regulating valve, 40 is a generator, 50 is a return oil tank, 60 is a standby oil pump, 70 is an oil-gas separator, 80 is a sealed oil filter, 90 is a make-up oil pipeline, 91 is a second regulating valve, 92 is a make-up oil filter, 100 is a sealed oil return pipeline, 101 is a return valve, and 110 is an expansion oil tank. Detailed implementation manners

[0040] The core of this application lies in disclosing a method for suppressing the vibration of a sealed oil pump of a generator, which suppresses the vibration of the sealed oil pump and ensures the normal operation of the generator.

[0041] Another core of this application lies in disclosing a sealed oil system for a generator, which is used for the method for suppressing the vibration of the sealed oil pump of the generator described above.

[0042] Next, the technical solutions in the embodiments of this application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in this application without making creative efforts shall fall within the protection scope of this application.

[0043] As Figure 2 shown, the embodiments of this application disclose a method for suppressing the vibration of a sealed oil pump of a generator, including the following steps:

[0044] Step S1: Control the vacuum pressure of the sealed oil tank 10 in stages;

[0045] The vacuum pressure of the sealed oil tank 10 is adjusted from normal pressure to the target vacuum pressure in stages. The staged adjustment method can reduce the occurrence of gas outburst phenomena in the sealed oil tank 10 and can reduce the vibration of the sealed oil pump 20.

[0046] Step S2: Vibration-vacuum linkage feedback;

[0047] According to the vibration speed of the sealed oil pump 20, the opening of the first regulating valve 31 located between the sealed oil tank 10 and the vacuum pump 30 or the frequency of the vacuum pump 30 is adjusted so that the vibration speed of the sealed oil pump 20 is within the vibration threshold range. Specifically, the vibration speed of the sealed oil pump 20 is obtained through a vibration detection element provided on the sealed oil pump 20. According to the relationship between the vibration speed and the vibration threshold, it is fed back to the first regulating valve 31 or the vacuum pump 30 for corresponding adjustment so that the vibration speed of the sealed oil pump 20 is within the vibration threshold.

[0048] Step S3: Dynamically compensate the net positive suction head;

[0049] Calculate the effective net positive suction head (NPSHa) of the seal oil pump 20 in real time. When the difference between the effective net positive suction head of the seal oil pump 20 and the required net positive suction head is less than the safety margin, that is, when NPSHa < NPSHr + safety margin (preferably 0.5 m), gradually increase the liquid level of the seal oil tank 10 according to the preset lifting height or gradually reduce the circulation flow rate of the seal oil according to the preset flow rate reduction. By adjusting the liquid level step by step and slowly, avoid transient cavitation of the seal oil pump 20 or system instability caused by drastic adjustment, and ensure stable pressure.

[0050] Step S4: Add defoamer;

[0051] Based on the foam thickness and gas content in the seal oil tank 10, the defoamer addition component adds defoamer into the seal oil tank 10. The defoamer can reduce the foam in the seal oil tank 10, reduce the occurrence of the phenomenon of false high liquid level, and can reduce the vibration of the seal oil pump 20. According to the foam thickness in the seal oil tank 10, the amount of defoamer added can be automatically adjusted. It should be noted that in actual operation, it can be determined whether to add defoamer according to the actual operation conditions.

[0052] The generator seal oil pump vibration suppression method disclosed in the embodiments of the present application can reduce the occurrence of gas outburst phenomenon in the seal oil tank 10 and reduce the vibration of the seal oil pump 20 by adjusting the vacuum pressure of the seal oil tank 10 in stages; by obtaining the vibration speed of the seal oil pump 20 and feedback-adjusting the opening of the first regulating valve 31 or adjusting the frequency of the vacuum pump 30, the vibration speed of the seal oil pump 20 can be made within the vibration threshold; by dynamically compensating the net positive suction head, cavitation of the seal oil pump 20 can be avoided and the occurrence of vibration of the seal oil pump 20 can be reduced; the addition of defoamer can reduce the foam in the seal oil tank 10 and reduce the occurrence of the phenomenon of false high liquid level. In the generator seal oil pump vibration suppression method disclosed in the embodiments of the present application, the above four steps work together, and through the staged adjustment method, the phenomenon of gas outburst in the seal oil tank can be reduced, the foam in the seal oil tank can be reduced, and the possibility of cavitation of the seal oil pump can be reduced, thereby reducing the vibration of the seal oil pump 20, ensuring the stability of the system, and ensuring the normal operation of the generator.

[0053] For the convenience of explaining the generator seal oil pump vibration suppression method, the following will be described in conjunction with the generator seal oil system. First, the generator seal oil system disclosed in the present application will be introduced.

[0054] As Figure 1 shown, the generator seal oil system disclosed in the embodiments of the present application includes a seal oil tank 10, a seal oil pump 20, a vacuum pump 30, a defoamer addition component, and a control component.

[0055] Among them, the sealed oil tank 10 is provided with a liquid level detection element 11 (detecting the liquid level), a vacuum degree detection element (detecting the vacuum degree), a foam thickness detection element (detecting the foam thickness), and a gas content detection element (detecting the gas content). The sealed oil tank 10 is connected to the makeup oil tank through a makeup oil pipeline 90, and a second regulating valve 91 is provided on the makeup oil pipeline 90. The makeup oil tank can supply oil to the sealed oil tank 10 through the makeup oil pipeline 90. By adjusting the opening and closing of the second regulating valve 91, the liquid level of the sealed oil tank 10 can be adjusted.

[0056] The sealed oil pump 20 is connected to the sealed oil tank 10 and is used to transport the sealed oil in the sealed oil tank 10 to the generator 40. The sealed oil pump 20 is provided with a vibration detection element, and the vibration detection element can detect the vibration speed of the sealed oil pump 20. The vacuum pump 30 is connected to the sealed oil tank 10 and is used to evacuate the sealed oil tank 10. A first regulating valve 31 is provided between the sealed oil tank 10 and the vacuum pump 30. The first regulating valve 31 is preferably an electric regulating valve. By adjusting the opening of the first regulating valve 31 or adjusting the frequency of the vacuum pump 30, the vacuum degree of the sealed oil tank 10 can be adjusted. Preferably, the vacuum degree of the sealed oil tank 10 is adjusted by adjusting the opening of the first regulating valve 31. An oil-gas separator 70 is provided between the sealed oil tank 10 and the vacuum pump 30 for separating the sealed oil and the gas in the sealed oil. The vacuum pump 30 is connected to the exhaust system to discharge the gas extracted from the sealed oil tank 10.

[0057] The defoamer adding assembly is connected to the sealed oil tank 10 and can add defoamer to the sealed oil tank 10. The liquid level detection element 11, the vacuum degree detection element, the foam thickness detection element, the gas content detection element, the first regulating valve 31, the vibration detection element, the vacuum pump 30, the second regulating valve 91, and the defoamer adding assembly are all connected to the control assembly.

[0058] It should be noted that the generator 40 includes an excitation end and a steam end, and both the excitation end and the steam end include an air-side oil passage and a hydrogen-side oil passage. Figure 1 For the shown generator 40, the left side is the excitation end and the right side is the steam end. Both the excitation end and the steam end include an air-side oil passage and a hydrogen-side oil passage. The oil in the sealed oil tank 10 is transported to the air-side oil passage and the hydrogen-side oil passage of the excitation end and the steam end through the oil supply pipeline.

[0059] Next, in combination with the generator seal oil system, the method for suppressing the vibration of the generator sealed oil pump will be introduced. Specifically, as Figure 3 shown, step S1 specifically includes the following steps:

[0060] Step S11, rapid degassing;

[0061] During the process of evacuating the sealed oil tank 10 with the vacuum pump 30, by adjusting the opening degree of the first regulating valve 31 or the frequency of the vacuum pump 30, the vacuum pressure of the sealed oil tank 10 is reduced from atmospheric pressure to the first preset vacuum pressure at the first preset gradient rate. The vacuum degree detection element can obtain the vacuum pressure of the sealed oil tank 10 and transmit it to the control component. The control component feeds back according to the vacuum pressure signal to the first regulating valve 31 or the vacuum pump 30 for corresponding adjustment until the vacuum pressure of the sealed oil tank 10 reaches the first preset vacuum pressure.

[0062] Step S12, deep degassing;

[0063] Maintain the vacuum pressure of the sealed oil tank 10 at the first preset vacuum pressure for the first preset time. When the first preset time is reached, the control component sends a signal to the first regulating valve 31 or the vacuum pump 30. By adjusting the opening degree of the first regulating valve 31 or the frequency of the vacuum pump 30, the vacuum pressure of the sealed oil tank 10 is reduced to the second preset vacuum pressure at the second preset gradient rate. Preferably, the second preset gradient rate is less than the first preset gradient rate.

[0064] Step S13, steady-state operation;

[0065] If the vibration speed of the sealed oil pump 20 exceeds the vibration threshold (preferably 2.8 mm / s), then the second preset vacuum pressure is gradually adjusted according to the preset pressure increment. The vibration detection element transmits the detected vibration speed of the sealed oil pump 20 to the control component. If the vibration speed exceeds the threshold, the control component sends a signal to the first regulating valve 31 or the vacuum pump 30. By adjusting the opening degree of the first regulating valve 31 or the frequency of the vacuum pump 30, the vacuum pressure of the sealed oil tank 10 is gradually adjusted according to the preset increment until the vibration speed of the sealed oil pump 20 is within the threshold range. The preset increment is preferably 1 kPa.

[0066] The applicant found through experiments that when the first preset gradient rate is 7 kPa / 10 minutes, the first preset vacuum pressure is 20 kPa, and / or the second preset gradient rate is 1 kPa / 20 minutes; and / or the range of the second preset vacuum pressure is 8 kPa - 10 kPa, the first preset time is preferably 1 hour, and the sealed oil tank 10 will not have the phenomenon of gas outburst, and the vibration of the sealed oil pump 20 is reduced. Of course, the above values are only examples, and in actual operation, adaptive adjustments can be made according to the actual situation.

[0067] Further, in step S2, the opening degree of the first regulating valve 31 = the first coefficient × the vibration amplitude of the sealed oil pump 20 within the second preset time + the second coefficient × the cumulative vibration amplitude of the sealed oil pump 20 within the second preset time; where the first coefficient is taken as 0.3 - 0.7, preferably 0.5, and the second coefficient is preferably 0.1 s -1; The vibration amplitude refers to the difference between the maximum and minimum values of the vibration speed of the seal oil pump 20 within the second preset time. That is, valve opening = K p (V max - V min ) + K i ∫(V max - V min )dt, where V max represents the maximum value of the vibration speed of the seal oil pump 20 within the second preset time, and V min represents the minimum value of the vibration speed of the seal oil pump 20 within the second preset time. The first coefficient K p = 0.3 - 0.7, and the second coefficient K i = 0.1s -1 . The applicant found through experiments that by adopting the above adjustment method, the vibration of the seal oil pump 20 can be reduced, so that the vibration of the seal oil pump 20 is within the vibration threshold. The second preset time is preferably 5S - 15S.

[0068] Further, in step S3, the liquid level of the seal oil tank 10 is adjusted by adjusting the second regulating valve 91 on the oil replenishing pipeline 90 connecting the replenishing oil tank and the seal oil tank 10; and / or, the flow rate of the seal oil return pipeline 100 parallel to the seal oil pump 20 is adjusted. Specifically, the opening and closing of the return valve 101 can be adjusted to make part of the seal oil flowing through the seal oil pump 20 return to the seal oil tank 10 to adjust the liquid level of the seal oil tank 10.

[0069] Specifically, in actual operation, the temperature and flow rate of the seal oil are constant, the height between the seal oil pump 20 and the seal oil tank 10 is fixed, and the control component can calculate the effective net positive suction head of the seal oil pump 20 in real time according to the vacuum degree measured by the vacuum degree detection element, the liquid level measured by the liquid level detection element, and the temperature, flow rate of the seal oil, and the height between the seal oil tank 10 and the seal oil pump 20.

[0070] When the difference between the effective net positive suction head of the seal oil pump 20 and the required net positive suction head is less than the safety margin (preferably 0.5m), the control component can send a signal to the second regulating valve 91, and the second regulating valve 91 opens to replenish oil into the seal oil tank 10 from the replenishing oil tank. When the increased value of the liquid level of the seal oil tank 10 reaches the preset lifting height, the control component sends a signal to the second regulating valve 91, and the second regulating valve 91 closes. When the difference between the effective net positive suction head of the seal oil pump 20 and the required net positive suction head is still less than the safety margin, the above operation is continued until the difference between the effective net positive suction head of the seal oil pump 20 and the required net positive suction head is greater than the safety margin. The preset lifting height can specifically be selected as 0.1m, 0.2m, etc., and can be specifically determined according to the actual situation. Preferably 0.1m, that is, the liquid level lifting step is set to 0.1m.

[0071] Further, as Figure 1 shown, in order to be able to adjust the flow rate of the seal oil pump 20 and adjust the liquid level height of the seal oil tank 10, the generator seal oil system further includes a seal oil return pipeline 100. The seal oil return pipeline 100 is connected to the seal oil tank 10. A return valve 101 is provided on the seal oil return pipeline 100. A flow detection element is provided downstream of the seal oil return pipeline 100. Both the flow detection element and the return valve 101 are connected to the control component. When the difference between the effective net positive suction head and the required net positive suction head of the seal oil pump 20 is less than the safety margin, the return valve 101 can be opened so that part of the oil flowing through the seal oil pump 20 returns to the seal oil tank 10 to increase the liquid level height of the seal oil tank 10.

[0072] Or, when the difference between the effective cavitation margin and the required cavitation margin of the seal oil pump 20 is less than the safety margin, the liquid level of the seal oil tank 10 can be adjusted by opening the return valve 101 to return part of the seal oil flowing through the seal oil pump 10 to the seal oil tank 10. Specifically, the circulating flow rate of the seal oil is gradually reduced according to a preset flow rate reduction. The preset flow rate reduction can be 1 m³ / h. Each time the flow rate of the seal oil is reduced by 1 m 3 / h, that is, the step size for reducing the circulating flow rate of the seal oil is set to 1 m³ / h until the difference between the effective cavitation margin and the required cavitation margin of the seal oil pump 20 is greater than the safety margin. Of course, the method of refueling the seal oil tank 10 through the makeup oil tank and returning the seal oil to the seal oil tank 10 by opening the return valve 101 can be carried out simultaneously.

[0073] Further, in step S4, the foam thickness detection element transmits the detected foam thickness of the seal oil tank 10 to the control component, and the gas content detection element transmits the detected gas content of the seal oil tank 10 to the control component. The control component calculates the content (volume of the defoamer) of the defoamer added to the seal oil tank 10 according to the above parameters and sends a signal to the defoamer adding component. The defoamer adding component adds an appropriate amount of defoamer into the seal oil tank 10. Specifically, the content of the defoamer = the third coefficient × (foam thickness - 50) + the fourth coefficient × (gas content - 1%). The third coefficient is preferably 0.1 L / (mm·h), and the fourth coefficient is preferably 0.1 (L / h).

[0074] In some specific embodiments, a temperature detection element and a flow detection element are further provided. The temperature detection element can detect the temperature of the seal oil, and the flow detection element can detect the flow rate of the seal oil pump 20. Both the temperature detection element and the flow detection element are connected to the control component.

[0075] Further, as Figure 1As shown in the figure, in order to recycle the seal oil of the generator 40, in some specific embodiments, the generator seal oil system further includes a return oil tank 50. The return oil tank 50 is connected to the generator 40. Specifically, after the seal oil in the hydrogen-side oil channels at the excitation end and the steam end converges, it flows into the return oil tank 50 through the return oil pipeline. The seal oil in the air-side oil channels at the excitation end and the steam end is mixed and then flows back to the makeup oil tank. In order to separate the sealed oil gas and liquid in the return oil tank 50, that is, to separate the hydrogen in the seal oil, the return oil tank 50 is connected to an expansion oil tank 110. The expansion oil tank 110 is connected to an air extraction assembly and the makeup oil tank. After the seal oil enters the expansion oil tank 110, its volume increases, and the hydrogen is separated out. The air extraction assembly extracts the hydrogen and discharges it into the atmosphere. The seal oil in the expansion oil tank 110 flows back to the makeup oil tank for recycling.

[0076] Furthermore, as Figure 1 shown, in order to ensure the normal operation of the system when the seal oil pump 20 fails, the generator seal oil system further includes a standby oil pump 60. The standby oil pump 60 is connected in parallel with the seal oil pump 20. In order to filter the seal oil, a seal oil filter 80 is provided between the seal oil pump 20 and the generator 40, and a makeup oil filter 92 is provided on the makeup oil pipeline 90.

[0077] The applicant conducts tests on a test platform using the generator seal oil pump vibration suppression method disclosed in this application. Among them, the vibration detection element uses a vibration sensor, which is installed on the non-drive end bearing housing of the seal oil pump 20; the foam thickness detection element uses a capacitance level gauge to monitor the foam thickness; the first regulating valve 31 is selected as an electric regulating valve. The second preset vacuum pressure is selected as 8 kPa(a), the vibration threshold is selected as 2.8 mm / s, and the initial dosing concentration of the defoamer (silicone type) is 50 ppm. The dynamic response curve of the vacuum pressure and the vibration speed obtained from the test is as Figure 4 shown. It can be seen from the figure that the vibration curve of the seal oil pump 20 is stable, and the vibration speed fluctuates around 0.5 mm / s, which is significantly lower than the vibration threshold of 2.8 mm / s.

[0078] At the same time, the applicant conducts tests on the on-site generator seal oil system. Through the tests, it is obtained that the vibration speed of the seal oil pump 20 drops from 5 mm / s - 6 mm / s to ≤1.5 mm / s, the gas content drops from 10% to ≤0.8%, the moisture residue ≤30 ppm; the vacuum pressure fluctuation ≤±0.3 kPa, the liquid level error ≤±3%, and the vibration of the seal oil pump 20 is maintained within the threshold range. It can be seen that the generator seal oil pump vibration suppression method disclosed in the embodiments of this application can reduce the vibration of the seal oil pump 20 and ensure the safe operation of the generator 40.

[0079] It should be noted that the various embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. For the same or similar parts among the embodiments, reference can be made to each other.

[0080] Hereinafter, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features.

[0081] In the description of the embodiments of the present application, it should be noted that unless otherwise clearly specified and limited, the terms "connected" and "coupled" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to specific circumstances.

[0082] Specific examples are used herein to illustrate the principles and implementation manners of the present application. The descriptions of the above embodiments are only used to help understand the core idea of the present application. It should be pointed out that for those of ordinary skill in the art of this technology, without departing from the principle of the present application, several improvements and modifications can be made to the present application, and these improvements and modifications also fall within the protection scope of the claims of the present application.

Claims

1. A method for suppressing vibration of a generator sealing oil pump, characterized in that: The steps include: Step S1, adjusting the vacuum pressure of the sealed oil tank (10) in stages, adjusting the vacuum pressure of the sealed oil tank (10) from normal pressure to a target vacuum pressure in stages; Step S2, vibration-vacuum linkage feedback, adjusting the opening of a first regulating valve (31) located between the sealing oil tank (10) and the vacuum pump (30) or adjusting the frequency of the vacuum pump (30) according to the vibration speed of the sealing oil pump (20), so that the vibration speed of the sealing oil pump (20) is within a vibration threshold range; Step S3, dynamically compensating the NPSH, calculating the effective NPSH of the sealing oil pump (20) in real time, and when the difference between the effective NPSH of the sealing oil pump (20) and the required NPSH is less than the safety margin, gradually raising the liquid level of the sealing oil tank (10) according to a preset lifting height or gradually reducing the circulation flow of the sealing oil according to a preset flow reduction; Step S4: adding a defoaming agent. Based on the foam thickness and gas content of the sealed oil tank (10), the defoaming agent adding component adds the defoaming agent into the sealed oil tank (10).

2. The method for suppressing vibration of a generator sealing oil pump according to claim 1, characterized in that: The step of controlling the vacuum pressure of the sealed oil tank (10) in stages specifically comprises: Step S11, rapid degassing, by adjusting the opening of the first regulating valve (31) or the frequency of the vacuum pump (30), so as to reduce the vacuum pressure of the sealing oil tank (10) from normal pressure to a first preset vacuum pressure at a first preset gradient rate; Step S12, deep degassing, maintaining a first preset vacuum pressure for a first preset time, and then adjusting the opening of the first regulating valve (31) or the frequency of the vacuum pump (30) so that the vacuum pressure of the sealed oil tank (10) drops to a second preset vacuum pressure at a second preset gradient rate; Step S13: steady-state operation: if the vibration speed of the sealing oil pump (20) exceeds the vibration threshold, the second preset vacuum pressure is gradually adjusted according to the preset pressure increment.

3. The method for suppressing vibration of a generator sealing oil pump according to claim 2, characterized in that: The first preset gradient rate is 7 kPa / 10 minutes, and the first preset vacuum pressure is 20 kPa; and / or, The second preset gradient rate is 1 kPa / 20 minutes; and / or, The second preset vacuum pressure ranges from 8 kPa to 10 kPa.

4. The method for suppressing vibration of a generator sealing oil pump according to claim 1, characterized in that: In the vibration-vacuum linkage feedback step, the opening degree of the first regulating valve (31)=first coefficient×vibration amplitude of the sealing oil pump (20) within the second preset time+second coefficient×accumulated vibration amplitude of the sealing oil pump (20) within the second preset time.

5. The method for suppressing vibration of a generator sealing oil pump according to claim 1, characterized in that: In the step of dynamically compensating the NPSH, the liquid level value of the sealing oil tank (10) is adjusted by adjusting the opening of a second regulating valve (91) on an oil replenishment pipeline (90) connecting the oil replenishment tank and the sealing oil tank (10); and / or, By adjusting the flow rate of a sealing oil return pipeline (100) connected in parallel with the sealing oil pump (20), part of the sealing oil flowing through the sealing oil pump (20) is returned to the sealing oil tank (10), thereby adjusting the liquid level of the sealing oil tank (10).

6. The method for suppressing vibration of a generator sealing oil pump according to claim 1, characterized in that: The foam thickness of the sealed oil tank (10) is measured by a foam thickness detection element, and the gas content of the sealed oil tank (10) is measured by an gas content detection element.

7. The method for suppressing vibration of a generator sealing oil pump according to claim 6, characterized in that: In the defoaming agent adding step, the content of the defoaming agent added to the sealed oil tank by the defoaming agent adding component is calculated according to the following formula: the content of the defoaming agent = the third coefficient × (foam thickness - 50) + the fourth coefficient × (gas content - 1%).

8. A generator sealing oil system, characterized in that: The method for suppressing vibration of a generator sealing oil pump according to any one of claims 1 to 7 comprises: A sealed oil tank (10), the sealed oil tank (10) being provided with a liquid level detection element (11), a vacuum detection element, a foam thickness detection element and an air content detection element, the sealed oil tank (10) being connected to the oil replenishment tank via an oil replenishment pipeline (90), and a second regulating valve (91) being provided on the oil replenishment pipeline (90); a sealing oil pump (20), the sealing oil pump (20) being in communication with the sealing oil tank (10) and being used for conveying the sealing oil in the sealing oil tank (10) to the generator (40), the sealing oil pump (20) being provided with a vibration detection element; a vacuum pump (30), the vacuum pump (30) being in communication with the sealing oil tank (10) and being used to evacuate the sealing oil tank (10), a first regulating valve (31) being provided between the sealing oil tank (10) and the vacuum pump (30), and the vacuum pump (30) being in communication with an exhaust system; A defoaming agent adding component, the defoaming agent adding component is connected to the sealing oil tank (10); A control component, wherein the liquid level detection element (11), the vacuum degree detection element, the foam thickness detection element, the gas content detection element, the first regulating valve, the vibration detection element, the vacuum pump (30), the first regulating valve (31) and the defoaming agent adding component are all connected to the control component.

9. The generator sealing oil system according to claim 8, characterized in that: It also comprises a sealing oil return pipeline (100), the sealing oil return pipeline (100) being connected to the sealing oil tank (10), a return valve (110) being provided on the sealing oil return pipeline (100), a flow detection element being provided downstream of the sealing oil return pipeline (100), the flow detection element and the return valve (110) being both connected to the control component.

10. The generator sealing oil system according to claim 8, characterized in that: It also includes an oil return tank, which is connected to the generator (40) and is used to collect sealing oil discharged from the generator (40), the oil return tank is connected to the expansion oil tank (50), the expansion oil tank (50) is connected to the air extraction component and the oil replenishment tank, and the oil replenishment tank is connected to the sealing oil tank (10).

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