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Time：2025-06-06 16:50:42 Reading volume：
Transformer oil filtration equipment is mainly used to purify transformer oil, remove pollutants such as moisture, gas, and solid particles, and ensure the insulation performance and heat dissipation efficiency of the transformer. When purchasing, factors such as equipment performance, filtration technology, brand reputation and after-sales service should be considered comprehensively. The following is a detailed purchasing guide:
1.1 Filtration goals
- Dehydration: Remove free water and dissolved water in oil (target: ≤10 ppm).
- Degassing: Remove dissolved gas (target: gas content ≤0.1%).
- Particle removal: Filter solid impurities (target: cleanliness NAS 1638 Class 6 or ISO 4406 15/13/10).
- Oil type: mineral oil, silicone oil, or synthetic ester oil (different oils need to match the equipment).
- Initial contamination: Highly contaminated oil requires a large flow or multi-stage filtration.
- Viscosity: High viscosity oil (such as a low temperature environment) requires a heating function (50~70℃).
- Flow selection: ｓｅｌｅｃｔ the equipment processing capacity according to the transformer oil volume (such as 500 L/h, 1000 L/h, 2000 L/h).
- Online or offline:
- Online filtration: Circulation purification without a power outage.
- Offline filtration: Centralized processing after shutdown.
| Type | Technical features | Applicable scenarios |
|------------------|---------------------------------------|----------------------------------|
| Vacuum oil filter | Vacuum dehydration + precision filtration, efficient water and gas removal | High-water content oil, new oil injection pre-treatment |
| Pressure oil filter | Intercept particles through the filter element, suitable for solid pollutant removal | Aged oil with serious particle pollution |
| Centrifugal oil filter | Centrifugal force separates impurities, suitable for large flow coarse filtration | Pretreatment or preliminary purification of highly polluted oil |
| Coalescing separation oil filter | Coalescing filter element + separator, specializing in water removal | Oil with high water content |
Recommended combination:
- High-water content oil: vacuum oil filter + coalescence dehydration.
- High-particle oil: centrifugal pre-filtration + pressure-type fine filtration.
3. Core performance parameters
3.1 Filtration accuracy
- Solid particles: 1~5 microns (fine filtration), 10~50 microns (coarse filtration).
- Moisture control: ≤10 ppm after vacuum dehydration (Karl Fischer method detection).
- Gas content: ≤0.1% after vacuum degassing.
3.2 Flow and power
- Flow range: 500~5000 L/h (ｓｅｌｅｃｔ according to the amount of transformer oil).
- Heating power: 15~30 kW (ensure that the oil temperature rises evenly to 60℃).
- Vacuum degree: -0.095 ~ -0.098 MPa (key to efficient dehydration).
3.3 Automation function
- PLC control: automatic adjustment of temperature, vacuum degree, and flow rate.
- Alarm protection: automatic shutdown for over-temperature, over-pressure, and lack of oil.
- Data recording: storage of historical filtration data for easy analysis.
4. Brand and supplier selection
- Pall: high-precision filtration, suitable for ultra-high voltage transformers.
- CJC (Denmark): specializes in the power industry, long-lasting filter elements.
- Hy-Pro (USA): leading coalescing and dehydration technology.
4.3 Supplier evaluation
- Certification: ISO 9001, CE, explosion-proof certification (Ex d IIB T4).
- Case: require the provision of successful cases of similar projects (such as power plants, substations).
- After-sales: whether to provide training, spare parts support, and emergency repairs.
5. Budget and cost analysis
| Equipment type | Price range (RMB) | Remarks |
|--------------------|-----------------------|---------------------------------|
| Small vacuum oil filter | 50,000~150,000 | Processing capacity ≤1000 L/h, basic functions |
| Medium multifunctional oil filter | 150,000~300,000 | With PLC control, suitable for substations |
| Large fully automatic oil filter | 300,000~800,000 | More than 5000 L/h, dedicated to the power industry |
Hidden costs:
- Filter element replacement: Annual consumables cost is about 10%~20% of the equipment price.
- Energy consumption: The power of the vacuum pump and heater affects the long-term electricity bill.
6. Acceptance criteria
1. Performance test:
- After filtration, the oil reaches: moisture ≤10 ppm, particle size ≤NAS 1638 Class 6.
- Vacuum system stability: -0.095 MPa for 30 minutes.
2. Operation inspection:
- No leakage, no abnormal noise.
- Automation functions (such as temperature control, alarm) are triggered normally.
3. Document acceptance:
- Factory inspection report, operation manual, warranty agreement.
When purchasing transformer oil filtration equipment, it is necessary to clearly define the filtration target, oil characteristics, and processing volume, ｓｅｌｅｃｔ a combination of vacuum, pressure, or coalescence technology, and pay attention to brand reputation, automation functions, and after-sales support. It is recommended to give priority to vacuum oil filters with PLC control and efficient dehydration capabilities, and strictly test the performance according to the acceptance standards.
