Why should the hottest transformer oil be filtered

2022-07-31
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Why should transformer oil be filtered

the purpose of filtration is to remove water and impurities in the oil, improve the electrical strength of the oil, protect the paper insulation in the oil, and improve the physical and chemical properties of the oil to a certain extent

distribution power transformers are mostly installed in the open air. The quality of insulating oil (transformer oil) is gradually deteriorated due to the influence of external impurities, air contact and high operating temperature of the equipment itself. The deteriorated insulating oil (transformer oil) will not play its due role in insulation and cooling. In order to prevent the safe operation from being affected due to the deterioration of oil quality, the normal distribution regular oil production samples shall be tested and analyzed, and the quality defects will be highlighted, and the oil shall be treated accordingly according to the analysis results. The inspection cycle for chemical supervision of power distribution operation oil shall be at least once every 3 years. Routine inspection items include acid value, water-soluble acid, flash point, breakdown voltage and appearance

it should be noted that if the equipment often has high load, the inspection times should be increased on the basis of the specified test cycle; If some indicators of the inspected items are obviously close to the controlled limit value, the inspection times shall also be increased; Since the quality of operating oil varies greatly with the aging degree and impurities, it is usually impossible to evaluate the oil quality based on only one test item. Comprehensive analysis shall be carried out according to the measured main characteristic indexes

1. The acid value exceeds the limit value by more than 0.1mgkoh/g. There are four possible reasons for the low temperature tank training of Jinan experimental machine factory which exceeds the limit: overload operation; Consumption of antioxidants; Fill the wrong oil; The oil is contaminated. For the acid value exceeding the limit value, the following countermeasures can be taken: investigate the causes, increase the test times, determine the antioxidant content and add it appropriately, conduct the regeneration treatment of transformer oil, and replace the oil if it is economical and reasonable

2. The over limit value of water-soluble acid is less than 4.2. There are two possible reasons for exceeding the limit value: oil aging; The oil is contaminated. For the water-soluble acid exceeding the limit value, the following countermeasures can be taken: increase the test times, and compare with the acid value to find out the causes. Carry out oil regeneration treatment. If it is economical and reasonable, replace the oil

3. The over limit value of breakdown voltage is less than 20kV. There are two possible reasons for exceeding the limit value: excessive water content in the oil; There is impurity particle pollution in the oil. For the breakdown voltage exceeding the limit value, the following countermeasures can be taken: find out the causes, conduct vacuum oil filtration, plate and frame pressure oil filter or replace with new oil. Generally, zjb vacuum oil filter is selected, and the breakdown voltage of oil after treatment is required to be greater than 50kV

4. If the flash point exceeds the limit value of less than 1, it is assumed that the tension machine fixture shall be selected at 30 ℃. Or 5 ℃ lower than the previous test value. There are two possible reasons for exceeding the limit value: local overheating fault of the equipment; The wrong oil was added. For the flash point exceeding the limit value, the following countermeasures can be taken: find out the cause and eliminate the fault; Degasify the vacuum oil filter or change the oil

5. Appearance: if the oil is opaque through visual inspection, there are visible impurities or suspended solids. Or if the oil color is too dark, the oil appearance is abnormal. The possible causes of abnormal appearance are: the oil contains moisture, fiber, carbon black and other solids. The following countermeasures shall be taken for the oil with abnormal appearance: if the oil is ambiguous and turbid, the spray free material also has obvious weakness, indicating that the oil contains water, the water content shall be checked. If it is found that the oil contains carbon particles, the oil is black, or even has a burnt smell, it may be that there is an internal arc or partial discharge fault, which should be combined with other tests to investigate the cause and eliminate the fault. If the oil is dark and the color of the oil has changed significantly, pay attention to whether the aging of the oil is accelerated. It can be analyzed in combination with the acid value test of the oil, or strengthen the monitoring of the operating temperature of the oil

varies greatly, and usually one test item cannot be used as the basis for evaluating oil quality. Comprehensive analysis shall be carried out according to the measured main characteristic indexes

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