The purpose of filtration is to remove moisture and impurities from oil products, improve the resistance of oil products, protect paper insulation in oil products, and to some extent improve the physical and chemical properties of oil products.
Distribution transformers are mostly installed in the open air. Insulation oil (transformer oil) is affected by external impurities, and its working temperature is higher when it contacts with air and the equipment itself, which makes the quality of oil worse gradually. The insulation oil (transformer oil) will not play its due role of insulation and cooling after deterioration. In order to prevent the deterioration of oil quality from affecting the safe operation of oil products, the normal oil production samples were tested and analyzed during the distribution period, and the oil products were processed according to the analysis results. The period of chemical supervision and inspection for oil products in distribution operation is at least 3 years. Routine test items include acid value, water soluble acid, flash point, breakdown voltage and appearance.
It should be noted that if the equipment is often under heavy load, the number of inspections should be increased on the basis of the prescribed test cycle; if some indicators of the inspection items are obviously close to the limit value of control, the frequency of inspection should also be increased; because the quality of the operating oil varies greatly with the aging degree and the impurities contained in the oil, Usually it is not possible to evaluate the quality of oil only through a test project. According to the main characteristic indicators measured, a comprehensive analysis is made.
1. 酸值超限值大于0.1mgkoh /g。超限原因有四种:超负荷运行;抗氧化剂消费;加错油了;油被污染了。可以采取以下对策酸值超过限值:调查原因,增加测试数量,确定抗氧化剂和补充适当的内容,进行变压器油的再生治疗,并取代石油,如果它是经济合理的。
1. The acid value exceeding the limit is more than 0.1 mgkoh/g. There are four reasons for exceeding the limit: overload operation; consumption of antioxidants; misfilling; oil pollution. The following countermeasures can be taken: investigating the causes, increasing the number of tests, determining antioxidants and supplementing appropriate content, treating transformer oil regeneration and replacing oil, if it is economical and reasonable.
2. The exceeding limit value of water-soluble acid is less than 4.2. There are two reasons for exceeding the limit: one is the aging of oil products; the oil is polluted. For water-soluble acids exceeding the standard, the following countermeasures can be taken: increase the number of tests, and compare with the acid value to find out the reasons. Oil regeneration treatment can be done if the economy is reasonable.
3. Its breakdown voltage is less than 20KV. There are two reasons for exceeding the standard: one is that there is too much water in the oil; the oil is polluted by impurity particles. For breakdown voltage exceeding the standard, the following countermeasures can be taken: to find out the reasons, vacuum oil filter treatment, plate and frame pressure oil filter treatment or replacement of new oil. The breakdown voltage of ZJB vacuum oil filter is generally over 50 KV.
4. The flash point limit is less than 130 C. Or 5 C lower than the previous test value. There are two reasons for exceeding the standard: partial overheating failure of equipment; wrong oil. Over the flash point limit, the following countermeasures can be taken: find out the causes, troubleshooting; vacuum oil degassing treatment, or oil exchange treatment.
Appearance such as oil opaque, visible impurities or suspended matter. Or oil color is too deep, oil appearance is abnormal. The possible causes of abnormal phenomena include the presence of water in solids such as oil, fibers and carbon black. For oil products with abnormal appearance, the following measures should be taken: oil products are blurred, turbid and white, indicating water content of oil products, water content should be checked. If carbon particles are found in the oil, the color of the oil turns black, or even the smell of coke, which may be internal arc or partial discharge fault, it should be combined with other tests to find out the cause and remove the fault. If the color of the oil is dark and the color of the oil changes obviously, we should pay attention to whether accelerating the aging of the oil, we can combine the acid value test and analysis of the oil, or strengthen the monitoring of the working temperature of the oil.