In order to improve the insulation strength and dielectric loss coefficient of transformer oil, the transformer oil must be treated before being injected into the oil tank to remove moisture, gas and impurities in the oil. In practical application, we deal with different types of transformer oil, and the effect is better.

1、对于一般被水和尘埃等杂质污染的变压器油,可以使用板框式压力过滤机,经过多次循环过滤,通常能够达到要求。它的原理就是利用滤油纸吸收水分、过滤杂质。因其构造简单、搬运方便,也得到广泛应用。缺点是过滤不彻底,对细微杂质去除效果不好,而且成本也比较高,当水分大时,滤油纸需频繁更换。

1. For the transformer oil which is generally polluted by water, dust and other impurities, the plate and frame pressure filter can be used. After many cycles of filtration, it can usually meet the requirements. Its principle is to use oil filter paper to absorb water and filter impurities. Because of its simple structure and convenient handling, it is also widely used. The disadvantage is that the filtration is not complete, the removal effect of fine impurities is not good, and the cost is relatively high. When the water content is large, the oil filter paper needs to be replaced frequently.

2、现在普遍采用的是真空滤油机,它不仅能彻底去除油中水分和气体,而且能有效去除微小杂质。其工艺流程是：待处理变压器油→粗过滤→精过滤→加热油真空脱水脱气→净油。粗过滤采用金属滤网和强磁铁,精过滤通常过滤1～μm微小杂质。

2. Vacuum oil filter is widely used now, which can not only completely remove water and gas in oil, but also effectively remove micro impurities. The technological process is as follows: transformer oil to be treated → coarse filtration → fine filtration → vacuum dehydration and degassing of heating oil → clean oil. Metal filter screen and strong magnet are used for coarse filtration, and 1-μ m micro impurities are usually filtered for fine filtration.
    

目前精过滤器的种类很多,有金属粉末烧结材料、金属微孔材料、陶瓷滤材以及采用特殊结构的滤纸滤蕊等。

At present, there are many kinds of fine filter, such as sintered metal powder, metal microporous material, ceramic filter material and filter core with special structure.

变压器油加热抽真空脱水脱气。其原理是把油罐内抽真空,将加热的变压器油用喷淋方法形成油雾,而使油中的气体和水分逸出。油温一般在65℃左右,不要太高,以免使油老化。这种方法脱水脱气效果比较好,是目前较普遍采用的方法。但是,如果油被喷成十分细小的雾状,则易被真空泵抽走。

The transformer oil is heated, vacuumed, dehydrated and degassed. The principle is to vacuum the oil tank and spray the heated transformer oil to form oil mist, which makes the gas and water in the oil escape. The oil temperature is generally around 65 ℃, not too high, so as to avoid oil aging. The dehydration and degassing effect of this method is better, which is widely used at present. However, if the oil is sprayed into a very fine mist, it is easy to be pumped away by the vacuum pump.

如果油被喷成具有一定直径的油珠 ,则由于油珠具有较高的界面张力,使得油珠内的水分和气体不易充分发挥。为此,喷汕孔的直径要选择适当,并且一般需在罐的抽空口处设置几道挡板,防止变压器油被真空泵抽走。

If the oil is sprayed into oil droplets with a certain diameter, the water and gas in the oil droplets are not easy to give full play to due to the high interfacial tension of the oil droplets. Therefore, the diameter of the spray hole should be selected properly, and several baffles should be set at the suction port of the tank to prevent the transformer oil from being pumped away by the vacuum pump.

目前,国外和国内还采用了一种比较先进的薄膜脱水脱气法,就是使进入罐中的油,经过一些脱气元件后形成极薄的油膜,并始终以油膜状态完成脱水脱气全过程,因而使油中的水分和气体容易去除。

At present, a relatively advanced membrane dehydration and degassing method is also adopted at home and abroad, which is to make the oil entering the tank form an extremely thin oil film after passing through some degassing elements, and complete the whole process of dehydration and degassing in the oil film state all the time, so that the water and gas in the oil can be easily removed.

3、被污染的变压器油的处理方法。被污染的变压器油(俗称污油),是指被混有极微小的杂质与油的分子相结合而形成的胶体污染的变压器油,以及经多年使用过的变压器油,一般为返修产品放出的油(此油的pH值已很低)。对这种污油则必须采用吸附的方法处理才能改善油的指标。

3. Treatment of contaminated transformer oil. The contaminated transformer oil (commonly known as dirty oil) refers to the transformer oil contaminated by colloid formed by the combination of extremely small impurities and oil molecules, and the transformer oil that has been used for many years. Generally, it is the oil discharged from repair products (the pH value of this oil is very low). This kind of dirty oil must be treated by adsorption method in order to improve the oil index.

一般多采用硅胶(SiO2)或活性氧化铝(A12O3)做吸附剂。污油处理系统中,为保证硅胶与变压器油充分接触,并便于更换硅胶,在硅胶罐内设置若干隔板,将硅胶装入小布袋内旋转,不可散装。经过加热后的变压器油送入硅胶罐,做一定时间的循环,使其充分发挥吸附效果后,再经滤油机注入到净油罐内。

Silica gel (SiO2) or activated alumina (A12O3) is usually used as adsorbent. In the waste oil treatment system, in order to ensure the full contact between silica gel and transformer oil and facilitate the replacement of silica gel, a number of separators are set in the silica gel tank, and the silica gel is put into a small cloth bag and rotated. It is not allowed to be in bulk. After being heated, the transformer oil is sent to the silica gel tank and circulates for a certain period of time to give full play to the adsorption effect, and then it is injected into the clean oil tank through the oil filter.

在处理过程中应定时监测,来判定吸附效果 ,当吸附效果不明显时,即应考虑更换硅胶。一般硅胶用量按重量计约占油的3%～5%。污油处理系统应与新油处理系统分开,以免交叉污染。装用过污油的罐、容器等,必须经过彻底清洗后才能再用于正常生产的油系统。

In the process of treatment, regular monitoring should be carried out to determine the adsorption effect. When the adsorption effect is not obvious, the replacement of silica gel should be considered. Generally, the amount of silica gel is about 3% - 5% of oil by weight. The waste oil treatment system should be separated from the new oil treatment system to avoid cross contamination. Tanks and containers containing used dirty oil must be thoroughly cleaned before they can be used in normal production oil system.