Maintenance measures of transformer oil

In winter, due to the cold weather low outdoor temperature, the oil level of transformer generally drops slightly according to the principle of physical thermal expansion cold contraction. When the oil level is lower than the low limit scale of the oil level gauge, oil should be added in time. In addition, the following common problems should be paid attention to in the management of transformer oil. Transformer oil plays an important role in enhancing insulation, accelerating heat dissipation, anti-corrosion arc extinguishing. During the operation of transformer, if oil leakage, oil level is too high too low, oil temperature is abnormal, oil color change so on are abnormal phenomena. If the transformer is allowed to continue to operate without management, it may cause power failure, equipment damage even fire. Therefore, maintenance technicians should strengthen the operation management of transformer in winter.

1. Prevent the oil level of transformer being too low

The rise fall of oil level in normal operation of transformer is caused by temperature change, the oil level change will be too large. When the oil level drops significantly, even the oil level can be seen the oil level gauge, it may be due to oil leakage oil leakage of the transformer, which is often caused by the damage of the transformer oil tank, the oil drain valve is tightened, the top cover of the transformer is tightly covered, the oil level gauge is damaged. If the oil level is too low, it will accelerate the aging of transformer oil worsen the insulation of transformer. Therefore, it is necessary to conduct more inspections, maintain more add oil in time.

2. Observe whether the transformer leaks oil

In case of serious oil leakage, the transformer shall be stopped in time for maintenance. When checking, first look for the oil leakage point. The oil leakage fault is easy to find, while the oil leakage fault is easy to find. Generally, the oil leakage occurs in the dust gathering humid places. If the transformer oil seeps the upper end cover, a circle of screws at the upper end shall be tightened; if the transformer oil seeps the gear, the stop cover shall be opened the compression screw inside shall be tightened; if the insulation pad is aged, the insulating oil pad shall be replaced in time.

3. Distinguish the quality of transformer oil by one smell two views

The transformer oil should be subjected to a withstand voltage test when it is used for 1-3 years. If the transformer oil can meet the technical requirements, it should be replaced filtered as soon as possible. Due to the high quality requirements of transformer oil, it is difficult to show whether the transformer oil is qualified without withstanding voltage test simplified test. However, through long-term practice, whether the transformer oil is qualified can be identified by one smell two views.

One smell: it is to identify the quality of transformer oil by smell. Qualified transformer oil should have no smell a little kerosene smell. If there are other odors, it means that the oil quality has deteriorated.

Two look: a look at the color of transformer oil. The new transformer oil is generally light yellow, will turn dark after oxidation. Second, see the transparency of transformer oil. The new transformer oil is transparent in glass bottle with blue purple fluorescence. If the fluorescence is lost no longer transparent, it indicates that there are free carbon mechanical impurities in the transformer oil.

4. Add transformer oil in time

Due to the cold weather in winter, the oil level of the transformer will generally drop. When the oil indicator is displayed, the oil should be added to the oil level line in time. When adding oil to the transformer in operation, it should be noted that the same brand of oil should be added into the transformer of 35kV above, the withstand voltage test should be conducted; the transformer of 10kV below can be added with different brands of oil, but the oil mixed withstand voltage test should be conducted. Gas relay should be checked after oil replenishment to release gas in time. Gas relay can be re connected to the trip circuit.

5. Avoid direct sunlight on transformer oil

The oxidation rate of transformer oil will be accelerated under the action of ultraviolet radiation. Therefore, transformer oil is allowed to be directly exposed to light. In order to prevent the transformer oil being exposed to light, it must be placed in an opaque container.

6. Check the temperature of the oil level thermometer on the top of the tank

Try to control the upper oil temperature of the transformer to exceed 85 ℃, that is, the difference between the upper oil temperature the room temperature should be less than 55 ℃. If the oil temperature rises suddenly when the transformer is in operation, it is the performance of overheating inside the transformer. The external causes are the serious overload of the transformer; the internal causes include iron core fire, winding inter turn short circuit, internal screw loosening, cooling device failure, etc.

7. Timely dispose of deteriorated transformer oil

If the transformer oil often overheats, runs absorbs moisture, the oil quality will be deteriorated. When using oil which can reach the standard value, it is easy to break down discharge between the winding the shell, resulting in serious accidents. Therefore, the insulating oil must be filtered regenerated. If the transformer oil is found to be damp, it should be dried; if it is found to be aged, it should be purified regenerated. The methods of separating transformer oil moisture impurities include filtration, drying clarification. Chemical treatment can also be used to remove the acid alkali in the oil, then dry filter the transformer oil to regenerate.