Transformer oil and transformer oil purifier
Transformer oil is a mineral oil extracted from petroleum. A good transformer oil should be a clean and transparent liquid, and there must be no sediment, suspended matter of mechanical impurities, and cotton-like matter. If it is contaminated and oxidized, it will produce resin and sediment, The oil quality of the transformer oil will deteriorate, and the color will gradually become light red, until it becomes a dark brown liquid. When the transformer has a fault, it will also change the color of the oil. Generally, it is not suitable when the transformer oil is light brown. Reused. In addition, the transformer oil can appear turbid milky, oily black, dark. Transformer oil turbid milky, indicating that the oil contains moisture. Darker oil color, indicating that the transformer oil insulation is aging. Oily black, or even Scorching odor, indicating a fault inside the transformer.
Transformer oil has the following main functions:
(1) Insulation transformer oil has much higher insulation strength than air. Immersion of the insulating material in oil not only improves the insulation strength, but also protects against moisture.
(2) Radiating effect The specific heat of transformer oil is large, and it is often used as a coolant. The heat generated during the operation of the transformer causes the oil close to the iron core and windings to expand due to heating. Through the up and down convection of the oil, the heat is dissipated through the radiator to ensure the normal operation of the transformer.
(3) Arc extinguishing acts on the on-load voltage regulating switch of the oil circuit breaker and transformer, and an arc will occur when the contacts are switched. Because the transformer oil has good thermal conductivity, and can contact a large amount of gas under the high temperature of the arc, generating a large pressure, thereby improving the arc extinguishing performance of the medium and causing the arc to extinguish quickly.
The performance of transformer oil usually has the following requirements:
(1) The density should be as small as possible to facilitate the precipitation of moisture and impurities in the oil.
(2) The viscosity should be moderate, too large will affect convection heat dissipation, and too small will reduce the flash point.
(3) The flash point should be as high as possible, and generally not lower than 135 ° C.
(4) The freezing point should be as low as possible.
(5) The lower the content of impurities such as acid, alkali, sulfur and ash, the better, so as to avoid their corrosion on insulation materials, wires, fuel tanks, etc. as far as possible.
(6) The degree of oxidation should not be too high. The degree of oxidation is usually expressed in terms of acid value, which refers to the amount of potassium hydroxide (mg) required to absorb 1 g of free acid in the oil.
(7) The degree of stability should not be too low. The degree of stability is usually expressed by the precipitate of the acid value test, which represents the ability of the oil to resist aging.
After understanding the main characteristics of transformer oil, we can understand that the transformer oil purifier is mainly used for dehydration, dedoping and degassing, so that the transformer oil can reach the serviceability again.