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1. Media
After the transformer body is dried and released from the furnace, it must go through processes such as body cleaning, boxing, external wiring, and tap-changer installation before vacuum oiling can be carried out. During this birth process, the insulating material in the body is always in contact with the atmosphere, and the insulating material must be Jamaica Sugar It absorbs moisture and affects the quality of the transformer.
Products with larger capacities and higher voltage levels have more complex structures and more insulating material content in their structures. The longer it takes to disassemble and clean up, the higher the level of moisture absorption. severe.
2. The principle of moisture absorption of insulated materials
After steam drying and meeting the requirements Jamaica Sugar The body is placed in the atmospheric Jamaicans Escort surroundings. Because after the insulating material is steam-dried, the moisture content is very low, generally around 0.5 and not exceeding 1. Because the partial pressure of water vapor in the surrounding environment is high, there will be a partial pressure difference between the partial pressure of water vapor in the insulating material and the surrounding environment in the atmosphere (that is, the partial pressure of water vapor in the insulating material(low partial pressure value compared with the surrounding conditions), for example, a 40000kva/110kv transformer body, assuming the water content is 0.JM Escorts8 , it has been out of the oven for 3 hours, the insulating temperature of the vessel is 65°C, and the water vapor partial pressure value is found to be 590pa from the Pieper curve (as shown in the figure); at this time, the ambient temperature of the atmosphere is 25°C, and the humidity is 65, and the ambient temperature is found to be 65°C. The partial pressure of water vapor is 2050pa, which exceeds 1460pa at the edge of the vessel. The moisture in the surrounding environment will migrate to the insulating material Jamaica Sugar Daddy, which means that the insulating material begins to absorb the surrounding environment moisture in it.
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In the initial stage, moisture absorption is limited to the surface layer. The moisture only reaches the peak value on the surface. As time goes by, the moisture changes position and disperses from the surface to the outside. At the same time, the temperature of the body gradually decreases with the longer it is out of the oven, so the partial pressure difference becomes larger and the moisture absorption becomes more serious. As the moisture absorption gradually deepens, the water content increases, and the water vapor content of the insulated material Jamaica Sugar Daddy will gradually increase until the saturation level is reached. The partial pressure of water vapor in the surrounding environment will cause moisture absorption.
3. Avoid moisture absorption on the Jamaicans Sugardaddy body. Method
During the manufacturing process of transformer products, due to long assembly time, high atmospheric humidity and other reasons, the body absorbs moisture, which frequently occurs in many transformer manufacturing companies. During on-site installation, it was found that the insulation resistance, acceptance ratio, dielectric loss, etc. of the transformer were significantly different from the factory test Jamaica Sugar Daddy values, and even The reason for the failure of power frequency withstand voltage is that the moisture absorption reaches a certain level, but the moisture content does not exceed 2, and the isolation is strong.The degree and extreme characteristics have not yet been reflected. In addition, when the equipment body was hoisted and inspected on site, it was exposed to the atmosphere again, and the temperature of the equipment body was already at normal temperature, and the partial pressure of water vapor of the insulating material was lower than the partial pressure of water vapor of the surrounding environment. . Therefore, there is more or less hygroscopicity, which increases the water content, causing some of the above indicators to deteriorate. Therefore, it is particularly important to prevent and control moisture absorption and dampness of the device body. JM Escorts
In the industry, there are generally the following methods to prevent and control moisture absorption and dampness of the instrument body:
⑴ Extension During disassembly, keep the body temperature low. This requires operators to have proficient operating skills and standardized procedures, and to make technical preparations and familiar drawings before giving birth; at the same time, it requires birth organizers to invest in necessary personnel and construct Jamaica Sugar Daddy has become a quick and easy delivery situation that does not miss work or spare time.
⑵ Enter the drying tank again for heating to increase the body temperature. Some products with complex structures often cannot be finished packing the cover box within the specified time, but they cannot allow the temperature of the body to drop. They need to be heated in the tank again to increase the temperature of the body and increase the partial pressure of water vapor in the insulating material. If the partial pressure of water vapor exceeds the surrounding environment, the material will not absorb moisture. Therefore, cleaning during the day and putting products into the furnace for heating and heat preservation at night are methods commonly used by various companies.
⑶ The device body should be steam-dried and vacuum oil-immersed before cleaning the device body. Through vacuum oil immersion, the transformer oil is immersed into the inside of the insulating material fiber, blocking the entry of moisture, Jamaicans Escort slowing down the moisture absorption rate, Increase disassembly time. However, due to the short oil immersion time Jamaica Sugar Daddy cannot completely penetrate the insulating material, and the contact between the oil and the atmosphere also causes water absorption and JM Escortsproblems such as low efficiency of childbirth and the body is susceptible to dust contamination. This method is more suitable for high voltage and large capacity products.
⑷ Use the air dryer to clean the machine body. For products with complex structures that require a long body processing process, a closed room can be used, and dry air processed by the air drying generator can be passed inward (the dew point is below –40°C). Due to the passage of dry air, positive pressure is always maintained in the closed room to prevent the entry of humid air. If there is any insulating material that needs to be disassembled in the fuel tank or used for external wiring for a long time, it should also be reported to the oil tank.Dry air is introduced into the box to maintain positive pressure, thereby protecting the insulation of the device and concentrating the operator’s exhaled moisture. This method is especially suitable for inspection and renovation of transformers at installation sites.
4. Dehumidification treatment to prevent moisture absorption on the surface of the device
Although we have taken measures to prevent and control moisture absorption during the manufacturing process of the product, it is not possibleJamaicans Sugardaddy is avoided due to the ambient humidity of the atmosphere JM Escorts Affected by the hygroscopicity of the insulating material of the body, some moisture is more or less absorbed on the surface of the insulating material. If it is not taken seriously or is not handled thoroughly, it will affect the operation of the transformer. Therefore, the method of vacuum dehumidification treatment was proposed.
When vacuuming, the pressure around the insulating material in the tank drops. When compared with the water Jamaica Sugar vapor partial pressure inside the insulating material When the value is still low, there is a partial pressure difference between the water vapor partial pressure around the insulating material and Jamaicans Escort. At this time, there is a partial pressure difference in the insulating material. The water begins to migrate outward. The higher the vacuum in the tank, the smaller the pressure in the surrounding space, the greater the pressure difference, and the water evaporates, Jamaica Sugar Daddy disperses, and migrates Also faster. After the vacuum reaches static stability, the water vapor component in the residual gas only accounts for a small part of the total residual gas. Actual measurement results show that the water vapor partial pressure accounts for about a few percent of the vacuum pressure. Generally, it can be considered as ≤3. If 3 is taken, when the actual air density is ≤133.3pa, the water vapor partial pressure is about 4pa. According to the equilibrium curve (Piper curve) of water content and water vapor partial pressure in the insulation, at a temperature of 10°C, water vapor When the partial pressure is 4pa to 5pa, the moisture content in the paper edge is about 0.5. It can be seen that as long as the vacuum degree is high enough and the Jamaicans Sugardaddy vacuuming time is long enough (it depends on the moisture absorption situation Depends), after reaching equilibrium, that isJamaica SugarDaddyEven at room temperature, the moisture in the insulating material can reach very low levels. If the surface insulation material absorbs serious moisture and has a high moisture content, it is best to heat and vacuum dehumidify the material in a drying tank.
In short, whether it is vacuum dehumidification treatment at room temperature or heating vacuum dehumidification treatment in a drying tank, the bottom line is Jamaicans EscortDuring the process of childbirth, efforts should be made to shorten the processing time of the body and keep the temperature of the body at a lower level, and to increase the first pass rate of childbirth and design, in order to shorten the processing time and improve the efficiency of childbirth.