A method for monitoring the oil mist concentration of turbine oil in a wind tunnel of a hydropower station generator

Abstract

The present invention discloses a method for monitoring the oil mist concentration of turbine oil in a wind tunnel of a hydropower station generator, which is aimed at the fact that there is no method for directly measuring the oil content in the air in the wind tunnel. Under normal circumstances, there is no other substance that can evaporate water in the wind tunnel of the generator except air, and only the oil mist in the oil tank evaporates or volatilizes, so the measured humidity and absolute humidity contain oil vapor components. By measuring and calculating the change of absolute humidity in the wind tunnel, and then correcting the influence of air change factors, the change value of the oil mist content in the air can be obtained.

Description

Technical Field

[0001] The invention relates to the technical field of transformers, and in particular to a method for monitoring the oil mist concentration of a turbine oil in a wind tunnel of a hydropower station generator. Background Art

[0002] The thrust bearings or guide bearings of the turbine generators in hydropower stations are generally lubricated with thin oil, and the lubricating medium is usually turbine oil. When the thrust bearings or guide bearings are arranged inside the wind tunnel, the oil mist inside the bearings will overflow into the wind tunnel. If the cooling method of the generator is closed self-circulating air cooling, the wind tunnel is a relatively closed space, and the oil mist overflowing into the wind tunnel cannot be discharged outside the wind tunnel. The oil mist has certain hazards to the electrical equipment of the generator and the maintenance personnel. It is necessary to measure or monitor the concentration of turbine oil mist inside the wind tunnel.

[0003] There is currently no direct method to measure the oil content in the air in a wind tunnel. Existing methods can only measure the content of a single element or a gas, such as various harmful substances in the air. Oil mist is a synthetic polymer. Currently, there is no direct measurement method that can be used for this project at home and abroad. The known methods for measuring oil mist concentration are as follows:

[0004] 1. Marine crankcase oil mist concentration measurement. Since the crankcase oil mist concentration is too high, the measurement range is different, and special equipment is used for detection, it has no reference significance.

[0005] 2. Test of oil mist concentration in compressed air of air compressor. The oil mist concentration test in compressed air of air compressor mainly uses a special oil mist test tube to detect the oil mist content in compressed air. The measurement range is 0-5mg / m 3 In order to test the oil mist concentration in the wind tunnel, the research team purchased the corresponding test tubes and sampling pumps, but several simulation tests in the factory were unsuccessful and no corresponding data could be measured. This aspect of work needs further research.

[0006] 3. A third-party testing agency uses the weighing method to test the water vapor (including various liquid vapors) and suspended matter content in the air in the wind tunnel. The testing method is as follows: Use a special air sampling device with a standard dry test paper to extract a certain amount of air in the wind tunnel and pass it through the standard test paper. Return to the laboratory and weigh the test paper with a high-precision balance. The weight increase is the total mass of other substances contained in the unit dry air. The mass measured by this method is the total amount of other substances in the air, including water vapor, oil mist, dust, etc. Because it contains many substances and has large interference factors, it is impossible to measure the oil mist content alone. Summary of the invention

[0007] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a method for monitoring the oil mist concentration of a turbine oil in a wind tunnel of a hydropower station generator, which indirectly calculates the oil mist concentration change in the wind tunnel by measuring the humidity changes in the generator wind tunnel and the environment.

[0008] In order to achieve the above technical effects, the object of the present invention is achieved as follows: A method for monitoring the oil mist concentration of turbine oil in a wind tunnel of a hydropower station generator, characterized in that the change of the oil content in the air in the wind tunnel is analyzed by monitoring the change of the absolute humidity inside the wind tunnel of the generator;

[0009] Humidity is a physical quantity that indicates the dryness of the atmosphere. At a certain temperature, the less water vapor a certain volume of air contains, the drier the air is; the more water vapor there is, the more humid the air is. The dryness or wetness of the air or the physical quantity that indicates the amount of water vapor it contains is called humidity. Humidity in meteorology refers to air humidity, which is the content of water vapor in the air. Liquid or solid water in the air is not counted in humidity.

[0010] The absolute humidity is the mass of water vapor contained in a unit volume of air, and the unit is g / m 3 , according to the definition of absolute humidity, the weight of water vapor in a certain volume of air can be calculated by measuring and calculating absolute humidity;

[0011] In daily life, the humidity referred to is relative humidity, which is the percentage of water vapor contained in the air to the saturated water vapor content under the same conditions as the air, and can be measured by a hygrometer;

[0012] Under normal circumstances, there is no other substance that can evaporate water in the generator wind tunnel except air. Only the oil mist in the oil tank evaporates or volatilizes. Therefore, the measured humidity and absolute humidity contain oil vapor.

[0013] By measuring and calculating the change in absolute humidity in the generator wind tunnel and then correcting the influence of air change factors, the change value of the oil mist content in the air can be obtained.

[0014] The specific steps include:

[0015] Absolute humidity calculation method:

[0016] The temperature and humidity meter measures the temperature and humidity at a certain time. Through the table of "Saturated water vapor content of air at different temperatures", the value of saturated water vapor content at the corresponding temperature can be found.

[0017] A = RH (%) × the value of saturated water vapor at the corresponding temperature (1)

[0018] in:

[0019] A is absolute humidity, in g / m 3 ;

[0020] RH (%) is relative humidity, which is the humidity % measured by a thermometer and hygrometer.

[0021] Data collection measurement method:

[0022] At least two temperature and humidity meters are installed at different locations in the wind tunnel to extract the internal environment data of the wind tunnel. At the same time, at least two temperature and humidity meters are installed at different locations in the workshop outside the wind tunnel to extract the external environment data of the wind tunnel.

[0023] The temperature and humidity meter measures humidity and temperature data at regular intervals, and then calculates the absolute humidity value by consulting the table "Saturated water vapor content of air at different temperatures";

[0024] Calculation method of oil mist concentration change in wind tunnel:

[0025] During the time period from t1 to t2, the change in oil mist concentration in the wind tunnel = absolute humidity difference in the wind tunnel - absolute humidity difference outside the wind tunnel, that is:

[0026] ΔN=ΔA-ΔA'(2)

[0027] ΔA=At2-At1(3)

[0028] ΔA'=A't2-A't1(4)

[0029] in:

[0030] ΔN is the change in oil mist concentration in the wind tunnel from time t1 to time t2;

[0031] ΔA is the absolute humidity difference in the wind tunnel from time t1 to time t2;

[0032] ΔA' is the absolute humidity difference outside the wind tunnel from time t1 to time t2;

[0033] At1 is the absolute humidity in the wind tunnel at time t1;

[0034] At2 is the absolute humidity in the wind tunnel at time t2;

[0035] A't2 is the absolute humidity outside the wind tunnel at time t1;

[0036] A't1 is the absolute humidity outside the wind tunnel at time t2;

[0037] If ΔN is positive, it means that the oil mist concentration increases, and the increase is the absolute value of ΔN; if ΔN is negative, it means that the oil mist concentration decreases, and the decrease is the absolute value of ΔN.

[0038] The present invention has the following beneficial effects:

[0039] The present invention indirectly calculates the change of oil mist concentration in the wind tunnel by measuring the change of humidity in and outside the wind tunnel of the generator. DETAILED DESCRIPTION

[0040] Embodiment 1:

[0041] A method for monitoring the oil mist concentration of turbine oil in a wind tunnel of a hydropower station generator analyzes the change of the oil content in the air in the wind tunnel by monitoring the change of the absolute humidity inside the wind tunnel of the generator.

[0042] The basic principles are:

[0043] Humidity is a physical quantity that indicates the dryness of the atmosphere. At a certain temperature, the less water vapor a certain volume of air contains, the drier the air is; the more water vapor there is, the more humid the air is. The dryness or wetness of the air or the physical quantity that indicates the amount of water vapor it contains is called humidity. Humidity in meteorology refers to air humidity, which is the content of water vapor in the air. Liquid or solid water in the air is not counted in humidity.

[0044] The absolute humidity is the mass of water vapor contained in a unit volume of air, and the unit is g / m 3 , according to the definition of absolute humidity, the weight of water vapor in a certain volume of air can be calculated by measuring and calculating absolute humidity;

[0045] In daily life, the humidity referred to is relative humidity, which is the percentage of water vapor contained in the air to the saturated water vapor content under the same conditions as the air, and can be measured by a hygrometer;

[0046] Under normal circumstances, there is no other substance that can evaporate water in the generator wind tunnel except air. Only the oil mist in the oil tank evaporates or volatilizes. Therefore, the measured humidity and absolute humidity contain oil vapor.

[0047] By measuring and calculating the change in absolute humidity in the generator wind tunnel and then correcting the influence of air change factors, the change value of the oil mist content in the air can be obtained.

[0048] Embodiment 2:

[0049] A method for monitoring the oil mist concentration of a turbine in a wind tunnel of a hydropower station generator comprises the following specific steps:

[0050] Absolute humidity calculation method:

[0051] The temperature and humidity meter measures the temperature and humidity at a certain time. Through the table of "Saturated water vapor content of air at different temperatures", the value of saturated water vapor content at the corresponding temperature can be found.

[0052] A = RH (%) × the value of saturated water vapor at the corresponding temperature (1)

[0053] in:

[0054] A is absolute humidity, in g / m 3 ;

[0055] RH (%) is relative humidity, which is the humidity % measured by a thermometer and hygrometer.

[0056] Data collection measurement method:

[0057] At least two temperature and humidity meters are installed at different locations in the wind tunnel to extract the internal environment data of the wind tunnel. At the same time, at least two temperature and humidity meters are installed at different locations in the workshop outside the wind tunnel to extract the external environment data of the wind tunnel.

[0058] The temperature and humidity meter measures humidity and temperature data at regular intervals, and then calculates the absolute humidity value by consulting the table "Saturated water vapor content of air at different temperatures";

[0059] Calculation method of oil mist concentration change in wind tunnel:

[0060] During the time period from t1 to t2, the change in oil mist concentration in the wind tunnel = absolute humidity difference in the wind tunnel - absolute humidity difference outside the wind tunnel, that is:

[0061] ΔN=ΔA-ΔA'(2)

[0062] ΔA=At2-At1(3)

[0063] ΔA'=A't2-A't1(4)

[0064] in:

[0065] ΔN is the change in oil mist concentration in the wind tunnel from time t1 to time t2;

[0066] ΔA is the absolute humidity difference in the wind tunnel from time t1 to time t2;

[0067] ΔA' is the absolute humidity difference outside the wind tunnel from time t1 to time t2;

[0068] At1 is the absolute humidity in the wind tunnel at time t1;

[0069] At2 is the absolute humidity in the wind tunnel at time t2;

[0070] A't2 is the absolute humidity outside the wind tunnel at time t1;

[0071] A't1 is the absolute humidity outside the wind tunnel at time t2;

[0072] If ΔN is positive, it means that the oil mist concentration increases, and the increase is the absolute value of ΔN; if ΔN is negative, it means that the oil mist concentration decreases, and the decrease is the absolute value of ΔN.

[0073] Furthermore, the table of "Saturated water vapor content of air at different temperatures" is specifically as follows:

[0074]

[0075] Embodiment 2:

[0076] Take a certain measurement data as an example to explain the specific oil mist concentration monitoring calculation process. (Oil mist concentration increases)

[0077] The temperature and humidity monitoring data of a unit inside and outside the wind tunnel on September 28, 2018 are as follows:

[0078] The temperature and humidity monitoring data of a unit inside and outside the wind tunnel on October 5, 2018 are as follows:

[0079]

[0080] The calculation is as follows:

[0081] ΔA=At2-At1

[0082] =12.91-15.85=-2.94

[0083] ΔA'=A't2-A't1

[0084] =13.31-16.76=-3.45

[0085] ΔN=ΔA-ΔA'

[0086] =-2.94-(-3.45)=0.51

[0087] That is, from September 28, 2018 to October 5, 2018, the oil mist concentration in the wind tunnel of a certain unit increased by 0.51g / m 3 .

Claims

1. A method for monitoring the oil mist concentration of turbine oil in a wind tunnel of a hydropower station generator, characterized in that: By monitoring the changes in absolute humidity inside the generator wind tunnel, the changes in oil content in the air in the wind tunnel are analyzed; By measuring and calculating the change in absolute humidity in the generator wind tunnel and then correcting the influence of air change factors, the change value of oil mist content in the air can be obtained; The monitoring method comprises the following specific steps: Absolute humidity calculation method: The temperature and humidity meter measures the temperature and humidity at a certain time. Through the table of "Saturated water vapor content of air at different temperatures", the value of saturated water vapor content at the corresponding temperature can be found. A=RH(%)×the value of saturated water vapor at the corresponding temperature; in: A is absolute humidity, in g / m³; RH (%) is relative humidity, that is, the humidity measured by the thermometer and hygrometer; Data collection measurement method: At least two temperature and humidity meters are installed at different locations in the wind tunnel to extract the internal environment data of the wind tunnel. At the same time, at least two temperature and humidity meters are installed at different locations in the workshop outside the wind tunnel to extract the external environment data of the wind tunnel. The temperature and humidity meter measures humidity and temperature data at regular intervals, and then calculates the absolute humidity value by consulting the table "Saturated water vapor content of air at different temperatures"; Calculation method of oil mist concentration change in wind tunnel: During the time period from t1 to t2, the change in oil mist concentration in the wind tunnel = the absolute humidity difference in the wind tunnel - the absolute humidity difference outside the wind tunnel, that is: ΔN=ΔA-ΔA'; ΔA=At2-At1; ΔA'=A't2-A't1; in: ΔN is the change in oil mist concentration in the wind tunnel from time t1 to time t2; ΔA is the absolute humidity difference in the wind tunnel from time t1 to time t2; ΔA' is the absolute humidity difference outside the wind tunnel from time t1 to time t2; At1 is the absolute humidity in the wind tunnel at time t1; At2 is the absolute humidity in the wind tunnel at time t2; A't1 is the absolute humidity outside the wind tunnel at time t1; A't2 is the absolute humidity outside the wind tunnel at time t2; If ΔN is positive, it means that the oil mist concentration increases, and the increase is the absolute value of ΔN; if ΔN is negative, it means that the oil mist concentration decreases, and the decrease is the absolute value of ΔN; The table of "Saturated water vapor content of air at different temperatures" is as follows: 。

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