Device and method for improving stability of generator stator cooling water system

Abstract

The invention discloses a device for improving the stability of a generator stator cooling water system. The device comprises a water supply tank, a water inlet is formed in the top of the water supply tank and communicates with a pressurization water tank through a pipeline, a bottom cover is arranged at the bottom of the water supply tank, and a push rod is connected to the bottom of the bottom cover and connected and linked with a motor; the problem that in the prior art, the pressure of the water tank is unstable, and no means for automatically maintaining the pressure stability exist is solved, the pressure stability of the water tank is maintained in time by additionally arranging the push type bottom cover on the water tank, water supplementing and pressurization are conducted on the water supply tank through the pressurization water tank, and the pressure and flow can be rapidly stabilized; various working condition changes can be automatically and accurately handled, faults are prevented, continuous and stable operation of a generator stator cooling water system is guaranteed, the maintenance cost and the shutdown risk are reduced, and the safety and reliability of overall operation of a generator are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of generators, and in particular to a device and method for improving the stability of a cooling water system of a generator. Background Art

[0002] The generator cooling water system is a very important system in a power plant. It is responsible for providing uninterrupted cooling water to the generator stator winding. It is usually equipped with generator water cut-off protection: when the cooling water flow is normal, the unit works normally. When the flow is lower than the design threshold, the unit trips after a short delay. Therefore, it is important to maintain the stability of the cooling water system.

[0003] At present, due to the unstable pressure of the water tank responsible for water supply in the prior art cooling water system, the inlet pressure decreases due to the drop in the water level of the high-level cooling water tank. When the pressure drops below the liquid vaporization pressure, the liquid begins to vaporize and produce bubbles. These bubbles will enter the impeller area of ​​the pump along with the water flow. Due to the high-speed rotation of the impeller, the bubbles are brought to the area with higher pressure. In the high-pressure area of ​​the impeller, the pressure around the bubbles is much higher than the pressure inside the bubbles. The bubbles cannot maintain their gaseous form and will collapse quickly. The collapse of bubbles is an instantaneous process that will produce a strong shock wave. This shock wave, like a tiny explosion, will produce a huge impact force on the impeller surface and the internal components of the pump, causing cavitation. The impact force generated by repeated bubble collapse will cause fatigue of the metal material on the impeller surface, resulting in pitting, pits, and even cracks on the impeller surface. As cavitation continues, the degree of damage to the impeller will gradually increase, eventually affecting the performance of the impeller and making it unable to transport liquid normally.

[0004] The reason for the unstable pressure of the water tank is mostly due to the aging and leakage of the water tank. Therefore, there is an urgent need to prevent the leakage of the water tank and to detect the leakage in time to avoid the occurrence of cavitation. A method and device for improving the stability of the generator cooling water system is needed. Summary of the invention

[0005] In order to solve the above-mentioned technical problems, the present invention provides a device and method for improving the stability of a generator cooling water system.

[0006] The technical solution of the present invention is achieved in this way:

[0007] A device for improving the stability of a generator cooling water system comprises a water supply tank, a water inlet is arranged on the top of the water supply tank, the water inlet is connected to a booster water tank through a pipeline, a bottom cover is arranged at the bottom of the water supply tank, a push rod is connected to the bottom of the bottom cover, and the push rod is connected to a motor and linked.

[0008] Preferably, the edge of the bottom cover is gap-matched with the inner wall of the water supply tank.

[0009] Preferably, the bottom cover has an edge that is inclined toward the middle.

[0010] Preferably, a pressure sensor and a liquid level sensor are provided in the water supply tank, and are connected to the master control system signal.

[0011] A method for improving the stability of a generator cooling water system comprises the following steps:

[0012] S1, obtain the water supply tank pressure value in real time through the pressure sensor and establish a value table;

[0013] S2, obtaining the flow value of the water supply tank in real time through the flow sensor and recording it in the table established in step S2;

[0014] S3, calculate the numerical ratio of water tank pressure and flow rate during normal operation, specifically expressed as, Among them, A1 is the outflow, A2 is the inflow, and P is the pressure; record the ratio C per unit time in the table;

[0015] S4, according to the ratio of step S3, obtain a set of ratios (C1, C2, C3...Cn), perform data cleaning and normalization on the set, and obtain a ratio threshold value within a normal working range;

[0016] S5, when the obtained ratio exceeds the ratio threshold, it is judged as an abnormal working state, and the liquid level sensor sends real-time liquid level data. When it is lower than the liquid level threshold, the booster tank replenishes water to the water supply tank. After the water replenishment is completed, the ratio is within the threshold, which is judged as a normal working state, otherwise it is judged as an abnormal working state, and the pressure value obtained by raising the height of the bottom cover of the water supply tank is calculated to see whether it meets the normal ratio threshold, and the height of the bottom cover of the water supply tank is raised according to the calculation result until the ratio threshold is continuously detected within a unit time;

[0017] S6, according to step S5, record the current height of the bottom cover of the water supply tank, send it to the master control system, and issue a prompt signal.

[0018] Preferably, the specific calculation formula for calculating whether the pressure value obtained by raising the height of the bottom cover of the water supply tank in step S5 meets the normal ratio threshold is:

[0019] Formula 1:

[0020] Formula 2: Among them, C 阈值 is the ratio threshold obtained in step S4, P0 is the current pressure value, ρ is the liquid density, g is the gravitational acceleration, and △h is the lifting height.

[0021] Preferably, in the water supply tank, the bottom cover lifting height limit is h0. By comparing △h with h0, when the limit height is greater than the lifting height, the lifting action can be performed. When the limit height is less than the lifting height, it is lifted to the limit height, and the booster tank is calculated to increase the water pump speed value to maintain the water supply tank pressure. The specific calculation method is to obtain the real-time pressure P2 of the water supply tank after lifting to the limit height, and the calculation formula of the required boost △P is:

[0022] Formula 1:

[0023] Formula 2:

[0024] Formula 3: Preferably, in step S5, the single lifting height is set to 1H, and after the required lifting height △h is calculated, when △h<2, the single lifting is 1H, when 2H<△h<5H, the single lifting is 2.5H, and when △h>5H, the single lifting is 4H.

[0025] Preferably, in step S5, after each lifting, the required lifting height △h is recalculated. The present invention solves the problem of unstable pressure of the water tank in the prior art and lack of means to automatically maintain stable pressure. By adding a push-type bottom cover to the water tank to timely maintain the pressure stability of the water tank, the water supply tank is replenished and pressurized by the booster water tank, which can quickly stabilize the pressure and flow, automatically and accurately respond to various working condition changes, prevent malfunctions, ensure the continuous and stable operation of the generator cooling water system, reduce maintenance costs and downtime risks, and improve the safety and reliability of the overall operation of the generator. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of a cooling water system for improving a generator according to the present invention.

[0027] Figure 2 It is a schematic diagram of a water supply tank of a device for improving the stability of a generator cooling water system according to the present invention; Figure 3 This is a schematic diagram of a method for improving the stability of a generator cooling water system of the present invention. In the figure: 1-water supply tank; 2-boosting water tank; 3-bottom cover; 4-push rod; 5-motor. DETAILED DESCRIPTION

[0028] In order to further explain the technical means and effects taken by the present invention to achieve the predetermined invention purpose, exemplary embodiments will be described in detail here, and examples thereof are shown in the accompanying drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the present application. Instead, they are only examples of methods and systems consistent with some aspects of the present application as detailed in the attached claims.

[0029] The terms used in this application are for the purpose of describing specific embodiments only and are not intended to limit the present application. The singular forms "a", "the", and "the" used in this application and the appended claims are also intended to include plural forms unless the context clearly indicates otherwise. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0030] Example 1

[0031] like Figure 1 and Figure 2 As shown, the present invention is a device for improving the stability of a generator cooling water system, comprising a water supply tank, a water inlet is arranged on the top of the water supply tank, the water inlet is connected to a booster water tank through a pipeline, a bottom cover is arranged at the bottom of the water supply tank, a push rod is connected to the bottom of the bottom cover, and the push rod is connected to the motor and linked.

[0032] Specifically, it includes a newly added booster water tank, a newly added bottom connecting pipe, a newly added bottom isolation valve, a newly added top connecting pipe and a newly added top isolation valve. The booster water tank is arranged at the side of the original high-position fixed cooling water tank and is connected in parallel with the original high-position fixed cooling water tank. The installation position is at the same height as the installation position of the original high-position fixed cooling water tank. The above structure is applied for a utility model patent and does not need to be described in detail in the present invention.

[0033] Preferably, the edge of the bottom cover is matched with the inner wall of the water supply tank, and the size of the gap is generally controlled within a very small range, such as between 0.1-0.5 mm. This gap can not only ensure that the bottom cover can move up and down smoothly in the water tank without being stuck due to excessive friction resistance, but also effectively prevent liquid leakage through a special sealing structure. During the movement of the bottom cover, the sealing structure between it and the inner wall of the water tank will be adaptively adjusted with the movement of the bottom cover to ensure that good sealing performance is always maintained. It is mainly necessary to make the water tank as a whole form a pressurized device to avoid the inability of the pressurized water tank to maintain pressure balance in a short time due to problems with the flow channel.

[0034] Preferably, the bottom cover is tilted toward the middle at the edge. When the bottom cover is lifted, the water flow converges toward the center along the tilted surface, forming a more regular water flow direction, reducing the dispersion and turbulence of the water flow at the bottom. Similarly, when the bottom cover is lowered, the water flow can also be evenly diffused to the surroundings along the tilted surface, avoiding the increase in resistance and local pressure fluctuations caused by the sudden change in direction of the water flow. For example, the tilt angle of the bottom cover is generally set between 10 and 30 degrees. After a large number of experiments, it has been verified that such an angle can significantly improve the stability and fluidity of the water flow.

[0035] Preferably, a pressure sensor and a liquid level sensor are provided in the water supply tank, which are connected to the master control system signal. The motor and the push rod are connected by a precise transmission mechanism, such as a high-precision coupling or a screw transmission device, to ensure that the rotational motion of the motor can be accurately converted into the linear lifting motion of the push rod, and that stable transmission efficiency and small transmission error can be maintained during the transmission process, thereby achieving precise control of the bottom cover height.

[0036] like Figure 3 As shown, a method for improving the stability of a generator cooling water system comprises the following steps:

[0037] S1, obtain the pressure value of the water supply tank in real time through the pressure sensor and establish a numerical table; use a high-precision pressure sensor, which has the characteristics of fast response and high sensitivity, and can monitor the pressure in the water supply tank in real time at very short time intervals. These pressure values ​​are immediately transmitted to the data processing unit and recorded in sequence according to the time series to construct a detailed numerical table. This table not only contains the instantaneous value of the pressure, but also can obtain the average value, maximum value, minimum value and pressure change rate and other derivative data through the calculation function of the data processing unit, providing information for a comprehensive understanding of the pressure status of the water supply tank.

[0038] S2, the flow sensor obtains the flow value of the water supply tank in real time and records it in the table established in step S2; at the same time, the flow sensor accurately measures the flow of the water supply tank at the same high frequency. The flow sensor uses advanced measurement technology, such as electromagnetic induction principle or turbine measurement principle, to ensure the accuracy of flow measurement within a very small error range. The collected flow values ​​are synchronously recorded in the table established in step S1, so that the pressure and flow data can be accurately corresponded in time and value, forming a complete system operation data matrix.

[0039] S3, calculate the numerical ratio of water tank pressure and flow rate during normal operation, specifically expressed as, Among them, A1 is the outflow, A2 is the inflow, and P is the pressure; record the ratio C per unit time in the table;

[0040] S4, according to the ratio of step S3, obtain a set of ratios (C1, C2, C3...Cn), clean and normalize the set, and obtain the ratio threshold within the normal working range; first, adopt an outlier detection method based on statistical principles. Calculate the mean μ and standard deviation σ of the ratio set (C1, C2, C3...Cn). For any ratio Ci, if | Ci-μ|>kσ (usually k is 3), the ratio Ci is judged as an outlier. For example, if the calculated mean μ = 0.5 and the standard deviation σ = 0.1, then when a ratio Ci is greater than 0.8 or less than 0.2, it will be marked as abnormal. This is because in normal and stable system operation, most ratios should be concentrated near the mean, and the probability of exceeding a certain range is affected by noise, sensor failure or instantaneous abnormal fluctuations of the system.

[0041] Secondly, use the sliding window technique. Set a suitable window size, such as a window of 10 data points. Within this window, analyze the trend of data changes. If the rate of change between a data point and the adjacent data points in the window exceeds the preset threshold, then the data point may be abnormal. For example, under normal circumstances, the rate of change of adjacent ratios is within 10%. If the rate of change of the ratio suddenly reaches 50% at a certain moment, then the data point is suspicious and needs further review.

[0042] Secondly, check the data consistency. Compare the timestamps of the pressure sensor and the flow sensor and the logical relationship of the data. If it is found that the pressure data jumps at a certain moment, but the flow data does not change reasonably at the same moment, or the change trends of the two are contradictory, then there may be problems with the relevant data points. For example, the pressure suddenly rises sharply, but the flow does not decrease (according to normal physical laws, the pressure increase may be due to flow obstruction, etc., and the flow should change). Such a data combination may be wrong and needs to be further verified or eliminated.

[0043] Finally, establish a data model to assist in data cleaning. Build a prediction model based on historical data from when the system is operating normally, such as using a linear regression model or a neural network model. Input the newly collected ratio data into the model, and the model will predict an expected ratio range. If the actual ratio exceeds this expected range, the data may be abnormal. In this way, the historical operating rules of the system can be used to identify data points that do not conform to the normal pattern, thereby improving the accuracy and reliability of data cleaning and laying a solid foundation for the subsequent precise determination of the ratio threshold.

[0044] S5, when the ratio obtained exceeds the ratio threshold, it is judged as an abnormal working state, and the liquid level sensor sends real-time liquid level data. When it is lower than the liquid level threshold, the booster tank replenishes the water supply tank. After the replenishment, if the ratio is within the threshold, it is judged as a normal working state, otherwise it is judged as an abnormal working state, and the pressure value obtained by the bottom cover of the water supply tank by raising the height is calculated to see whether it meets the normal ratio threshold, and the height of the bottom cover of the water supply tank is raised according to the calculation result until the ratio threshold is continuously detected within the unit time; when the pressure-flow ratio calculated in real time exceeds the ratio threshold determined in step S4, the system is judged as an abnormal working state. This is because under normal operating conditions, there is a relatively stable relationship between pressure and flow, and the ratio should fluctuate within the threshold range. Once the ratio exceeds the threshold, it means that the pressure and flow balance inside the system is broken, which may be caused by a variety of reasons, such as water tank leakage causing pressure drop, water pump failure affecting flow supply, pipe blockage changing water flow resistance, etc. At this time, the liquid level sensor plays a role and sends real-time liquid level data. If the liquid level is lower than the preset threshold, it means that there is insufficient water in the water tank, which may be caused by leakage or other reasons. The booster tank will automatically start to refill the water supply tank. During the refilling process, the system continuously monitors the changes in pressure and flow data, because refilling will change the pressure and flow relationship in the water tank. When the refilling is completed, the pressure-flow ratio is calculated again. If the ratio returns to the threshold, it means that the system has resumed normal working state, which may be due to an abnormality caused by insufficient water; if the ratio still exceeds the threshold, it means that there are other problems in the system, which require further in-depth analysis and processing.

[0045] Preferably, the specific calculation formula for calculating whether the pressure value obtained by raising the height of the bottom cover of the water supply tank in step S5 meets the normal ratio threshold is:

[0046] Formula 1:

[0047] Formula 2: Among them, C 阈值 is the ratio threshold obtained in step S4, P0 is the current pressure value, ρ is the liquid density, g is the gravitational acceleration, and △h is the lifting height.

[0048] Preferably, in the water supply tank, the bottom cover lifting height limit is h0. By comparing △h with h0, when the limit height is greater than the lifting height, the lifting action can be performed. When the limit height is less than the lifting height, it is lifted to the limit height, and the booster tank is calculated to increase the water pump speed value to maintain the water supply tank pressure. The specific calculation method is to obtain the real-time pressure P2 of the water supply tank after lifting to the limit height, and the calculation formula of the required boost △P is:

[0049] Formula 1:

[0050] Formula 2:

[0051] Formula 3: Preferably, in step S5, the single lifting height is set to 1H, and after the required lifting height △h is calculated, when △h<2, the single lifting is 1H, when 2H<△h<5H, the single lifting is 2.5H, and when △h>5H, the single lifting is 4H.

[0052] Preferably, in step S5, after each lifting, the required lifting height △h is recalculated. In the water supply tank, there is a bottom cover lifting height limit. When the calculated lifting height is less than the limit height, the motor drives the push rod to drive the bottom cover to lift to a corresponding height. During the lifting process, the system pressure and flow changes are continuously monitored. According to the actual situation, it may be necessary to adjust the bottom cover height multiple times, and the required lifting height is recalculated after each adjustment. When the calculated lifting height is greater than the limit height, the bottom cover is lifted to the limit height, and then the booster tank pump speed value is calculated to maintain the water supply tank pressure. By lifting the bottom cover to the limit height and increasing the booster tank pump speed, additional pressure support is provided to the system to compensate for the lack of pressure that may be caused by the inability to continue lifting the bottom cover, so that the system pressure-flow ratio is restored to normal as much as possible to maintain the stable operation of the generator cooling water system.

[0053] S6, according to step S5, record the height of the bottom cover of the current water supply tank, send it to the master control system, and send a prompt signal. The system will record the height of the bottom cover of the current water supply tank in detail and send it to the master control system. The master control system uses advanced industrial control computers or programmable logic controllers (PLCs) with powerful data processing and storage capabilities. At the same time, a prompt signal is issued, which can be an audible and visual alarm signal, or an alarm message sent to a remote monitoring terminal through network communication. So that the operation and maintenance personnel can timely and comprehensively grasp the operating status of the system and the adjustment of equipment, and provide strong data support and decision-making basis for subsequent maintenance and management work. Based on this information, the operation and maintenance personnel can further inspect and optimize the system, such as regularly checking the accuracy of sensors, cleaning pipeline filters, and maintaining equipment such as booster tanks and water pumps to ensure long-term and stable operation of the system. Through this series of steps that are closely coordinated and linked together, the generator cooling water system can maintain a high degree of stability and reliability under various complex working conditions, effectively reduce the probability of failure, and extend the service life of the system. In addition, this height point can maintain stable pressure. In other words, if there is leakage on the surface of the water tank below this height point, the maintenance personnel can query the height of the last lift when lifting to the current height. This height is the location of the leakage point. For example, if the last lift was 1H, then the current height is h c , which means that hc The local area 1H below is where the leakage occurs.

[0054] Preferably, the maintenance personnel will carry out precise repairs on the identified leak points. Use appropriate welding, sealant plugging or replacement of damaged parts to ensure that the leak is completely sealed. After the repair is completed, a strict pressure test is carried out to gradually increase the pressure of the water supply tank to a level higher than the normal operating pressure, observe whether there is leakage again, and monitor whether the flow rate is stable within the normal range. If the pressure and flow rate remain stable within a preset time (such as 30 minutes), it indicates that the leak has been repaired successfully; preferably, after the repair is completed, the bottom cover falls back to the normal range, and steps S5 and S5 are repeated to return the bottom cover to the starting point.

[0055] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A device for improving the stability of a generator cooling water system, characterized in that: It comprises a water supply tank, the top of which is provided with a water inlet, the water inlet is connected with a pressurized water tank through a pipeline, a bottom cover is provided at the bottom of the water supply tank, a push rod is connected with a motor at the bottom of the bottom cover, and the push rod is connected with a motor and linked.

2. The device for improving the stability of a generator cooling water system according to claim 1, characterized in that: The edge of the bottom cover is clearance-matched with the inner wall of the water supply tank.

3. The device for improving the stability of a generator cooling water system according to claim 1, characterized in that: The bottom cover has an edge that is inclined toward the middle.

4. The device for improving the stability of a generator cooling water system according to claim 1, characterized in that: The water supply tank is provided with a pressure sensor and a liquid level sensor, which are connected to the master control system signal.

5. A method for improving the stability of a generator cooling water system, characterized in that: The steps include: S1, obtain the water supply tank pressure value in real time through the pressure sensor and establish a value table; S2, obtaining the flow value of the water supply tank in real time through the flow sensor and recording it in the table established in step S2; S3, calculate the numerical ratio of water tank pressure and flow rate during normal operation, specifically expressed as, Among them, A1 is the outflow, A2 is the inflow, and P is the pressure; record the ratio C in each unit time in the table; S4, according to the ratio of step S3, obtain a set of ratios (C1, C2, C3...Cn), perform data cleaning and normalization on the set, and obtain a ratio threshold value within a normal working range; S5. When the obtained ratio exceeds the ratio threshold, it is judged as an abnormal working state, and the liquid level sensor sends real-time liquid level data. When the liquid level is lower than the threshold, the booster tank replenishes the water supply tank. After the replenishment, if the ratio is within the threshold, it is judged as a normal working state. Otherwise, it is judged as an abnormal working state. The pressure value obtained by raising the height of the bottom cover of the water supply tank is calculated to see whether it meets the normal ratio threshold. The height of the bottom cover of the water supply tank is raised according to the calculation result until the ratio threshold is continuously detected within a unit time. S6. According to step S5, the current height of the bottom cover of the water supply tank is recorded and sent to the master control system to issue a prompt signal.

6. A method for improving the stability of a generator cooling water system according to claim 5, characterized in that: The calculation formula for calculating whether the pressure value obtained by raising the height of the bottom cover of the water supply tank in step S5 meets the normal ratio threshold is as follows: Formula 1: Formula 2: Among them, C 阈值 is the ratio threshold obtained in step S4, P0 is the current pressure value, ρ is the liquid density, g is the gravitational acceleration, and Δh is the lifting height.

7. A method for improving the stability of a generator cooling water system according to claim 5, characterized in that: In the water supply tank, the bottom cover lifting height limit is h0. Comparing Δh with h0, when the limit height is greater than the lifting height, the lifting action can be performed. When the limit height is less than the lifting height, it is lifted to the limit height, and the booster tank is calculated to increase the water pump speed value to maintain the water supply tank pressure. The specific calculation method is to obtain the real-time pressure P2 of the water supply tank after lifting to the limit height, and the calculation formula of the required boost ΔP is: Formula 1: Formula 2: Formula 3:

8. The method for improving the stability of a generator cooling water system according to claim 5, characterized in that: In step S5, the single lifting height is set to 1H, and after the required lifting height Δh is calculated, when Δh<2, the single lifting is 1H, when 2H<Δh<5H, the single lifting is 2.5H, and when Δh>5H, the single lifting is 4H.

9. A method for improving the stability of a generator cooling water system according to claim 5, characterized in that: In step S5, after each lifting, the required lifting height Δh is recalculated.

Images