How many days does it take to filter the transformer oil?

The time for transformer oil filtering depends on many factors, usually 1 to 7 days, and the specific situation needs to be comprehensively judged according to the following circumstances:

Key influencing factors

1. Oil contamination degree

- Mild contamination (micro-water, small amount of impurities): 1 to 2 days.

- Severe contamination (high water content, many particles, excessive acid value): 3 to 7 days, or even longer.

2. Type of oil filtering equipment

- Ordinary pressure oil filter: slow processing, may need to run continuously for 3 to 5 days.

- Vacuum oil filter (high efficiency dehydration and degassing): fast speed, usually 1 to 3 days.

- Centrifugal oil filter: suitable for removing large amounts of water and impurities, but may require multiple cycles.

3. Oil volume

- Small transformer (hundreds of liters of oil): 1 to 2 days.

- Large transformer (tons of oil): 3 to 7 days, need to be processed in batches.

4. Target oil standard

- Only preliminary filtration is required (such as removing particles): 1 day.

- Need to meet high standards (such as water content <10ppm, withstand voltage >60kV): Repeated filtration is required, which takes longer.

5. Environmental conditions

- High temperature and low humidity environment can accelerate water evaporation and shorten the time; humid and cold environment may prolong the process.

Typical process reference

1. Pretreatment: coarse filtration to remove large particles (about 4~8 hours).

2. Deep treatment: vacuum dehydration and degassing (24~72 hours, depending on the moisture content).

3. Fine filtration: remove trace impurities through molecular sieves or adsorbents (optional, add 12~24 hours).

4. Inspection and acceptance: sampling and testing indicators such as breakdown voltage, moisture, dielectric loss, etc. (need to stop the machine for inspection; time is calculated separately).

Notes

- Real-time monitoring: check oil quality every 4~8 hours to avoid excessive filtration or equipment idling.

- Safe operation: When filtering oil, the oil temperature must be controlled (usually 50~60℃) to prevent local overheating.

- Transformer status: If the oil is filtered under power (hot oil circulation), the regulations must be strictly followed and the time may be extended.

Recommendations

- Consult the manufacturer: formulate a plan based on the specific equipment model and oil quality report.

- Staged treatment: In case of severe contamination, some oil can be treated first and then replaced gradually.

The final time must be based on the actual oil quality standard and cannot be estimated based on experience alone.