Preparation method of special insulating cooling liquid for static var generator

Abstract

The invention relates to the technical field of static var generator cooling, in particular to a preparation method of a special insulating cooling liquid for a static var generator, which comprises the following steps: step 1, selecting a non-metal container, cleaning the container by using deionized water subjected to ozone-ultraviolet combined treatment, and drying the container by using a drying oven; and detecting that the conductivity of the cleaned aqueous solution is lower than 0.8 mu S / cm, and then injecting deionized water into the container as a basic solvent. According to the preparation method of the special insulating cooling liquid for the static var generator, disclosed by the invention, the folded microfiltration membrane filter, the ion exchange column, the roll type ultrafiltration membrane filter and the nanofiltration membrane filter are sequentially used, so that impurities with different particle sizes and properties in a solution can be effectively removed; the leakage short circuit risk during high-voltage operation of the static var generator is reduced, and the insulation performance is greatly improved.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of static var generator cooling, in particular to a preparation method of special insulating cooling liquid for static var generators. BACKGROUND

[0002] In a modern power system, as an advanced reactive power compensation device, a static var generator (SVG) plays a key role in maintaining power grid voltage stability, improving power quality and reducing line loss due to its characteristics of rapid response and continuous adjustment of reactive power. SVG realizes reactive power compensation through high-frequency switching of power electronic devices, and a large amount of heat is generated during operation of the power electronic devices. If the heat cannot be dissipated in time and effectively, the performance of the devices will be reduced or even damaged, which seriously affects the normal operation and service life of the SVG.

[0003] At present, the preparation method of the SVG insulating cooling liquid on the market still has the following problems: 1. In the treatment of the base solvent, the conventional deionized water cleaning method cannot remove the trace impurities and microorganisms remaining in the water, which will affect the insulating performance and chemical stability of the cooling liquid. Long-term use will easily lead to a decrease in the internal insulation performance of the equipment and increase the risk of electric leakage and short circuit; 2. In the solute dissolving process, the traditional method mainly adopts simple normal temperature stirring, and the solute dissolving efficiency is low and uneven, which leads to unstable performance of the cooling liquid and affects the heat dissipation effect; 3. In addition, the existing filtration technology cannot effectively remove impurities of different particle sizes and properties in the solution, especially the ion impurities and small particles, so that the prepared cooling liquid has high conductivity and cannot meet the insulation requirements of the high-voltage operation of the SVG. Therefore, the application provides a preparation method of special insulating cooling liquid for static var generators. SUMMARY

[0004] The main purpose of the application is to provide a preparation method of special insulating cooling liquid for static var generators, which can effectively solve the problems in the background art.

[0005] To achieve the above purpose, the technical scheme adopted by the application is as follows:

[0006] A preparation method of special insulating cooling liquid for static var generators, comprising the following steps:

[0007] Step 1: select a non-metallic container, first clean the container with deionized water treated by ozone-ultraviolet combination, detect the conductivity of the water solution after cleaning, and the conductivity is less than 0.8 mu S / cm, then inject deionized water into the container as a base solvent;

[0008] Step two, put the non-electrolyte solute into a planetary ball mill for grinding to make its particle size reach 20-50 mesh, then add it to the container by using the gradient temperature dissolution method, control the temperature rising rate at 1-2 ℃ / min, monitor the solution temperature at the same time, and make the solution temperature maintain at 25-35 ℃, to obtain a mixed solution A;

[0009] Step three, use an anchor stirrer to stir the mixed solution A at a speed of 250-350 r / min, and turn on the ultrasonic generator at the same time, the ultrasonic frequency is 20-40 kHz, and the ultrasonic power density is 0.1-0.3 W / cm 2 , and the stirring and ultrasonic treatment are cooperated for 30-60 minutes;

[0010] Step four, filter the mixed solution A through a folded microfiltration membrane filter with a pore size of 0.05-0.5 microns, an ion exchange column filled with chelating ion exchange resin and macroporous adsorption resin, a roll-type ultrafiltration membrane filter with a molecular weight cut-off of 500-2000 daltons, and a nanofiltration membrane filter;

[0011] Step five, use an online precision conductivity meter with temperature compensation function to detect the solution conductivity in real time, when the conductivity at 25 ℃ is lower than 0.3 μS / cm, pour the prepared static no-load generator special insulating cooling liquid into a passivated stainless steel container, seal and store in a nitrogen-filled environment, and the oxygen content in the nitrogen is lower than 5 ppm.

[0012] Preferably, during the process of adding non-electrolyte solute by using the gradient temperature dissolution method, after adding the solute each time, stir for 5-10 minutes at the current temperature, and then continue to add solute by increasing the temperature.

[0013] Preferably, when stirring and ultrasonic treatment of the mixed solution A, the temperature of the solution is regulated by a jacketed container to maintain the solution temperature at 28±1 ℃.

[0014] Preferably, pressure sensors and flow control valves are arranged between the folded microfiltration membrane filter, ion exchange column, roll-type ultrafiltration membrane filter and nanofiltration membrane filter, and the solution flow rate is automatically adjusted to 3-8 L / min by a PLC control system according to the pressure and flow data.

[0015] Preferably, when using the online precision conductivity meter to detect the conductivity, record and analyze the data every 5 minutes, and if the fluctuation of the detection data exceeds 0.05 μS / cm for three times in a row, start the circulating filtration program.

[0016] Preferably, the passivated stainless steel container is subjected to high-temperature calcination treatment before use, the calcination temperature is 200-300 ℃, the calcination time is 1-2 hours, and then the vacuum degree reaches 10 acooling to room temperature under the environment of 5-10℃.

[0017] Preferably, after the mixed solution A is filtered through the ion exchange column, an antioxidant with a mass fraction of 0.01-0.05% is added to the solution, and the antioxidant is a compound of hindered phenol and phosphite.

[0018] Preferably, before the cooling liquid is poured into the container for sealed storage, the cooling liquid is subjected to laser particle size analysis, and if particles with a particle size greater than 1 micrometer are detected, the filtering process is re-performed.

[0019] Preferably, the deionized water is pre-purified by a reverse osmosis membrane device before being subjected to ozone-ultraviolet combined treatment, and the desalination rate of the reverse osmosis membrane is not less than 99%.

[0020] Preferably, during the storage of the cooling liquid after sealed storage, the nitrogen pressure in the container is regularly detected, and when the pressure drops by more than 10% of the initial pressure, nitrogen is supplemented to the initial pressure.

[0021] Compared with the prior art, the present application has the following beneficial effects:

[0022] 1、In the present application, the deionized water treated by ozone-ultraviolet combined treatment is used to clean the container and as the base solvent, compared with the traditional deionized water, it can further remove the trace impurities and microorganisms remaining in the water, ensuring the high cleanliness of the container and the solvent, and the electrical conductivity of the aqueous solution after cleaning is less than 0.8 μS / cm, laying a foundation for preparing low-conductivity insulating cooling liquid, at the same time, through multi-stage filtering treatment, the folding microfiltration membrane filter, ion exchange column, roll-type ultrafiltration membrane filter and nanofiltration membrane filter are used in turn, which can effectively remove impurities of different particle sizes and properties in the solution, including suspended solids, ionic impurities and macromolecular substances, finally making the prepared cooling liquid have an electrical conductivity of less than 0.3 μS / cm at 25℃, significantly reducing the risk of leakage and short circuit of the static var generator during high-pressure operation, and greatly improving the insulation performance.

[0023] 2、In the present application, the electrolyte-free solute is ground to 20-50 mesh in a planetary ball mill to refine the particle size of the solute and increase the contact area with the solvent, at the same time, a gradient temperature dissolution method is adopted, the solute is slowly added at a temperature rising rate of 1-2℃ / min, and after each addition, the current temperature is maintained for 5-10 minutes of stirring, the stirring speed is 250-350 revolutions per minute, the ultrasonic frequency is 20-40 kHz, the power density is 0.1-0.3 W / cm 2 , the synergistic effect lasts for 30-60 minutes, and the solution temperature is controlled at 28±1℃ by a jacketed container, these measures effectively accelerate the dissolution process of the solute, make the solute more uniformly dispersed in the solution, ensure the uniformity of the mixed solution A, and further ensure the stable performance of the cooling liquid and improve the heat dissipation efficiency.

[0024] 3、In the application, in the multi-stage filtration process, pressure sensors and flow control valves are arranged between each filtration device, and the solution flow rate is automatically adjusted to 3-8 L / min by the PLC control system according to the pressure and flow data. This intelligent control method can adjust the flow rate in real time according to the filtration condition, avoid insufficient filtration due to too fast flow rate, or affect production efficiency due to too slow flow rate, ensure efficient and stable filtration process, effectively improve the purity of the coolant, and at the same time, in the conductivity detection link, data recording and analysis is performed every 5 minutes, if the fluctuation of the detection data exceeds 0.05 μS / cm for three times in a row, the circulation filtration program is started, further ensuring the stability and reliability of the coolant conductivity;

[0025] 4、In the application, a stainless steel container treated by passivation is selected, and high-temperature calcination treatment is performed before use, and then cooled to room temperature in a vacuum degree of 10-2-10-3 Pa a , effectively removing impurities and active substances on the surface of the container, improving the chemical stability of the container, sealing in an environment with oxygen content less than 5 ppm nitrogen during sealing and storage, and regularly detecting the nitrogen pressure in the container during storage. When the pressure drops by more than 10% of the initial pressure, supplement the nitrogen. This storage method can effectively isolate air, prevent coolant oxidation and contamination, and at the same time, after the mixed solution A is filtered through the ion exchange column, 0.01-0.05% of the hindered phenolic and phosphite compound antioxidant is added, further enhancing the antioxidant performance of the coolant, prolonging its service life, and reducing equipment maintenance cost and safety hazards. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 The application provides a preparation method of an insulating coolant special for a static var generator. DETAILED DESCRIPTION

[0027] In order to make the technical means, creative features, purposes and effects of the application easy to understand, the application is further described below in combination with specific embodiments.

[0028] Please refer to Figure 1 , the application provides a technical solution:

[0029] A preparation method of an insulating coolant special for a static var generator, comprising the following steps:

[0030] Step 1: Select a non-metallic container, first clean the container with deionized water treated by ozone-ultraviolet combination, detect that the conductivity of the water solution after cleaning is lower than 0.8 μS / cm, and then inject deionized water into the container as a base solvent;

[0031] Step two, put the non-electrolyte solute into a planetary ball mill for grinding to reach a particle size of 20-50 mesh, then add it to the container using a gradient temperature dissolution method, control the temperature rising rate at 1-2℃ / min, monitor the solution temperature at the same time, and maintain the solution temperature at 25-35℃ to obtain a mixed solution A;

[0032] Step three, use an anchor stirrer to stir the mixed solution A at a speed of 250-350 rpm, and turn on the ultrasonic generator at the same time, with an ultrasonic frequency of 20-40 kHz and an ultrasonic power density of 0.1-0.3 W / cm 2 , and stir for 30-60 minutes under the synergistic effect of stirring and ultrasonic;

[0033] Step four, filter the mixed solution A through a folded microfiltration membrane filter with a pore size of 0.05-0.5 microns, an ion exchange column filled with chelate ion exchange resin and macroporous adsorption resin, a roll-type ultrafiltration membrane filter with a molecular weight cutoff of 500-2000 daltons, and a nanofiltration membrane filter;

[0034] Step five, use an online precision conductivity meter with temperature compensation function to detect the solution conductivity in real time, when the conductivity at 25℃ is lower than 0.3 μS / cm, pour the prepared static generator special insulation cooling liquid into a passivated stainless steel container, seal and store in a nitrogen-filled environment, and the oxygen content in the nitrogen is less than 5 ppm.

[0035] In this embodiment, during the addition of non-electrolyte solute using the gradient temperature dissolution method, after adding the solute each time, stir for 5-10 minutes at the current temperature, and then continue to add solute while increasing the temperature; when stirring and ultrasonic treatment of the mixed solution A, the temperature of the solution is controlled by a jacketed container to maintain the solution temperature at 28±1℃; pressure sensors and flow control valves are provided between the folded microfiltration membrane filter, ion exchange column, roll-type ultrafiltration membrane filter and nanofiltration membrane filter, and the solution flow rate is automatically adjusted to 3-8 liters / min by the PLC control system according to the pressure and flow data; when using the online precision conductivity meter to detect the conductivity, record and analyze the data every 5 minutes, if the fluctuation of the detection data exceeds 0.05 μS / cm for three times in a row, start the circulating filtration program; the passivated stainless steel container is subjected to high temperature calcination treatment before use, the calcination temperature is 200-300℃, the calcination time is 1-2 hours, and then the vacuum degree reaches 10-2-10-3P aThe cooling liquid is cooled to room temperature in the environment; after the mixed solution A is filtered through an ion exchange column, 0.01-0.05% of an antioxidant, which is a compound of a hindered phenol and a phosphite, is added to the solution; before the cooling liquid is poured into a container for sealed storage, the cooling liquid is subjected to laser particle size analysis, and if particles with a particle size greater than 1 micron are detected, the filtering process is performed again; the deionized water is pre-cleaned through a reverse osmosis membrane device before being subjected to ozone-ultraviolet combined treatment, and the desalination rate of the reverse osmosis membrane is not less than 99%; during the storage of the cooling liquid after sealed storage, the nitrogen pressure in the container is regularly detected, and when the pressure drops by more than 10% of the initial pressure, nitrogen is supplemented to the initial pressure.

[0036] The above shows and describes the basic principles and main features of the present application and the advantages of the present application. Those skilled in the art should understand that the present application is not limited by the above examples, and the above examples and descriptions in the specification are only to illustrate the principles of the present application, and various changes and improvements can be made to the present application without departing from the spirit and scope of the present application, and these changes and improvements all fall within the scope of the claimed present application. The scope of protection of the present application is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a special insulating coolant for a static var generator, characterized in that, Includes the following steps: Step 1: Select a non-metallic container and clean it with deionized water that has been treated with ozone and ultraviolet light. After cleaning, test the conductivity of the aqueous solution to be less than 0.8 μS / cm. Then, inject deionized water into the container as the base solvent. Step 2: Grind the electrolyte-free solute in a planetary ball mill until the particle size reaches 20-50 mesh. Then add it to the container using a gradient heating dissolution method, with the heating rate controlled at 1-2℃ / min. At the same time, monitor the solution temperature and maintain it at 25-35℃ to obtain mixed solution A. Step 3: Use an anchor stirrer to stir solution A at a speed of 250-350 rpm, while simultaneously turning on the ultrasonic generator at a frequency of 20-40 kHz and a power density of 0.1-0.3 W / cm³. 2 Stirring and ultrasound work together for 30-60 minutes; Step 4: The mixed solution A is filtered sequentially through a pleated microfiltration membrane filter with a pore size of 0.05-0.5 micrometers, an ion exchange column filled with chelating ion exchange resin and macroporous adsorption resin, a spiral wound ultrafiltration membrane filter with a molecular weight cutoff of 500-2000 Daltons, and a nanofiltration membrane filter. Step 5: Use an online precision conductivity meter with temperature compensation function to detect the conductivity of the solution in real time. When the conductivity is less than 0.3 μS / cm at 25℃, pour the prepared static var generator special insulating coolant into a passivated stainless steel container and seal it in a nitrogen-filled environment with an oxygen content of less than 5 ppm.

2. The method for preparing a special insulating coolant for a static var generator according to claim 1, characterized in that, When adding electrolyte-free solutes using the gradient temperature dissolution method, after each addition of solute, maintain the current temperature and stir for 5-10 minutes before continuing to increase the temperature and add more solute.

3. The method for preparing a special insulating coolant for a static var generator according to claim 1, characterized in that, When mixing solution A with stirring and ultrasound, the temperature of the solution is controlled by a jacketed container to maintain the solution temperature at 28±1℃.

4. The method for preparing a special insulating coolant for a static var generator according to claim 1, characterized in that, Pressure sensors and flow control valves are installed between the pleated microfiltration membrane filter, ion exchange column, spiral wound ultrafiltration membrane filter and nanofiltration membrane filter. The solution flow rate is automatically adjusted to 3-8 liters / minute by the PLC control system based on the pressure and flow data.

5. The method for preparing a special insulating coolant for a static var generator according to claim 1, characterized in that, When using an online precision conductivity meter to test conductivity, data should be recorded and analyzed every 5 minutes. If the fluctuation of the data exceeds 0.05 μS / cm for three consecutive tests, the cyclic filtering program should be started.

6. The method for preparing a special insulating coolant for a static var generator according to claim 1, characterized in that, Before use, the passivated stainless steel container undergoes a high-temperature firing treatment at 200-300℃ for 1-2 hours, followed by firing under a vacuum of 10⁻²-10⁻³ P. a Cool to room temperature in an environment with [specific conditions].

7. The method for preparing a special insulating coolant for a static var generator according to claim 1, characterized in that, After the mixed solution A is filtered through an ion exchange column, an antioxidant with a mass fraction of 0.01-0.05% is added to the solution. The antioxidant is a complex of hindered phenols and phosphites.

8. The method for preparing a special insulating coolant for a static var generator according to claim 1, characterized in that, Before pouring the coolant into a sealed container for storage, perform laser particle size analysis on the coolant. If particles larger than 1 micrometer are detected, the coolant is filtered again.

9. The method for preparing a special insulating coolant for a static var generator according to claim 1, characterized in that, Before being treated with ozone and ultraviolet light, the deionized water is pre-purified by a reverse osmosis membrane device, and the desalination rate of the reverse osmosis membrane is not less than 99%.

10. The method for preparing a special insulating coolant for a static var generator according to claim 1, characterized in that, During the storage of coolant after sealing, the nitrogen pressure inside the container should be checked periodically. When the pressure drops by more than 10% of the initial pressure, nitrogen should be added to restore the initial pressure.

Images