① The insulating oil is deteriorated.

包括它的物理和化学性能都发生变化，从而使其电性能变坏。通过测试绝缘油的酸值、界面张力、汕泥析出、水溶性酸值等项目，可判断是否属于该类缺陷，，对绝缘油进行再生处理，可能消除油变质的产物，但处理过程中也可能去掉了天然抗氧剂。

Including its physical and chemical properties have changed, so that its electrical properties deteriorated. By testing the acid value, interfacial tension, sludge precipitation, water-soluble acid value and other items of insulating oil, it can be judged whether it belongs to this kind of defect. If the insulating oil is regenerated, the product of oil deterioration may be eliminated, but the natural antioxidant may also be removed during the treatment process.

② 绝缘油进水受潮，由于水是强极性物质。

② The insulating oil is affected by moisture because water is a strong polar substance.

在电场的作用下易电离分解，而增加了绝缘油的电导电流，因此，微量的水分可使绝缘油介质损耗显著增加。通过测试绝缘油的微水，叮判断是否属于该类缺陷。对绝缘油进行压力式真空滤油，一般能消除水分。

Under the action of electric field, it is easy to ionize and decompose, and the conductivity current of insulating oil is increased. Therefore, the dielectric loss of insulating oil can be significantly increased by a small amount of water. By testing the tiny water of insulating oil, we can judge whether it belongs to this kind of defect. In general, moisture can be eliminated by pressure vacuum oil filtration.

③ 绝缘油感染微生物细菌。

③ Insulating oil is infected with microorganism and bacteria.

例如在主变压器安装或吊芯时，附在绝缘件表面的昆虫和安装人员残留的闩：渍等都有可能携带细菌，从而感染了绝缘油：或者绝缘油本身已感染微生物。主变压器—·般运行在40—80℃的环境下，非常有利于这些微生物的生长、繁殖。由于微生物及其排泄物中的矿物质、蛋白质的绝缘性能远远低于绝缘油，从而使得绝缘油介损升高。这种缺陷采用现场循环处理的方法很难处理好，因为无论如何处理，始终有一部分微生物残留在绝缘固体上。处理后，短期内主变压器绝缘会有所恢复，但由于主变压器运行环境非常有利于微生物的生长、繁殖，这些残留微生物还会逐年生长繁殖，从而使某些主变压器绝缘逐年下降;

For example, when the main transformer is installed or hung, the insects attached to the insulation surface and the bolts and stains left by the installation personnel may carry bacteria, which may infect the insulating oil or the insulating oil itself has been infected with microorganisms. The main transformer is generally operated at 40-80 ℃, which is very conducive to the growth and reproduction of these microorganisms. The dielectric loss of insulating oil increases because the insulating properties of minerals and proteins in microorganisms and their excreta are much lower than that of insulating oil. It is difficult to deal with this defect by on-site circulation treatment, because in any case, some microorganisms remain on the insulating solid. After treatment, the insulation of the main transformer will recover in a short time. However, because the operating environment of the main transformer is very conducive to the growth and reproduction of microorganisms, these residual microorganisms will grow and reproduce year by year, so that the insulation of some main transformers will decrease year by year;

④ 含有极性物质的醇酸树脂绝缘漆溶解在油中。

④ Alkyd insulating paint containing polar substances is dissolved in oil.

在电场的作用下，极性物质会发生偶极松弛极化，在交流极化过程中要消耗能量，所以使油的介质损耗上升。虽然绝缘漆在出厂前经过固化处理，但仍可能存在处理不彻底的情况。主变压器运行一段时间后，处理不彻底的绝缘漆逐渐溶解在油中，使之绝缘性能逐渐下降。该类缺陷发生的时间与绝缘漆处理的彻底程度有关，通过一两次吸附处理可取得一定的效果。

Under the action of electric field, polar materials will have dipole relaxation polarization, which consumes energy in the process of AC polarization, so the dielectric loss of oil increases. Although the insulating paint is cured before leaving the factory, there may still be incomplete treatment. After the main transformer has been running for a period of time, the insulation paint which has not been treated thoroughly is dissolved in the oil gradually, which makes its insulation performance gradually decline. The occurrence time of such defects is related to the thorough degree of insulating paint treatment, and certain effect can be achieved through one or two adsorption treatments.

⑤ 油中只混有水分和杂质。

⑤ The oil is only mixed with moisture and impurities.

这种污染情况并不改变油的基本性质。对于水分可用干燥的办法加以排除;对于杂质可用过滤的办法加以清除;油中的空气可通过抽真空的办法加以排除。

This contamination does not change the basic properties of the oil. Water can be removed by drying; impurities can be removed by filtering; air in oil can be removed by vacuuming.

⑥ 两种及两种以上不同来源的绝缘汕混合使用。

⑥ Two or more insulation materials from different sources are used together.

油的性质应符合相关规定;油的比重相同、凝固温度相同、粘度相同、闪点相近;且混合后油的安定度也符合要求。对于混油后劣化的油，由于油质已变，产生了酸性物质和油泥，闽此需用油再生的化学方法将劣化产物分离出来，才能恢复其性质。

The properties of the oil should comply with the relevant regulations; the oil has the same specific gravity, the same solidification temperature, the same viscosity, and the similar flash point; and the stability of the mixed oil should also meet the requirements. For the deteriorated oil mixed with oil, because the oil quality has changed, acid substances and oil sludge are produced. Therefore, the chemical method of oil regeneration is needed to separate the deteriorated products to recover their properties.