EnglishViews: 0 Author: Site Editor Publish Time: 2026-06-23 Origin: Site
Transformer oil inevitably absorbs moisture, gas, and particulate impurities during long-term operation. These contaminants severely reduce the oil's insulation performance, thereby weakening the transformer's internal insulation strength. When insulation performance drops to a critical value, it may cause short circuits or even major power outages, posing a significant risk to the power grid.
Therefore, regularly using efficient transformer oil filtration equipment is a key means to extend the lifespan of power transformers and ensure power supply reliability.
This article will focus on how vacuum oil filters, through dehydration, degassing, and precision filtration, can improve the insulating oil's properties to meet international standards such as IEC 60422, providing practical selection references for substation maintenance personnel.
What Technical Points Should Be Considered for Transformer Oil Purification Equipment?
| Flow Rate Selection: |
Choosing the correct processing flow rate is the primary technical decision. Chongqing Gold Mechanical & Electrical Equipment Co.,Ltd. ZJA products cover a flow rate range from 1800 L/H to 12000 L/H, allowing users to flexibly select the appropriate equipment based on the transformer oil volume. Taking the ZJA-6KY model as an example, its nominal flow rate is 6000 L/H, equivalent to a processing capacity of 100 L/min, suitable for the maintenance needs of medium-capacity transformers. For small distribution transformers or maintenance scenarios with low oil volume, smaller flow rate models of 1800 L/H or 3000 L/H can be selected to avoid cost waste caused by excessive equipment capacity; for large main transformers or situations requiring rapid processing, a larger flow rate model of 12000 L/H can be selected to significantly shorten on-site operation time.
The core basis for selection is the total oil volume of the transformer to be processed and the available maintenance window time—selecting the smallest suitable model within the equipment flow range that can complete the circulating filtration on time, to balance equipment investment and operational efficiency. |
| Vacuum System Configuration |
The vacuum system determines the actual effect of dehydration and degassing. A two-stage vacuum configuration using a Roots pump and a vacuum pump can achieve a working vacuum degree ≤80 Pa and an ultimate vacuum degree ≤7 Pa. This combination can rapidly reduce water content in oil from ≤50 ppm to ≤10 ppm and gas content from ≤10% to ≤0.3% under lower vacuum conditions. With only a single-stage vacuum system, processing the same batch of oil often takes much longer. For substation on-site maintenance, the dual-stage vacuum structure can significantly shorten the oil filtration cycle and improve operational efficiency. |
| Mobility Options: |
Substation environments are diverse, ranging from indoor distribution rooms to remote outdoor substations where oil filtration operations may be performed. Equipment mobility options include open-type and trailer-mounted configurations. The trailer-mounted configuration uses a dedicated trailer mechanism on the chassis, equipped with forklift tires and an impact-type hydraulic brake system. The towing speed must not exceed 50 km/h, making it ideal for mobile maintenance between multiple substations and emergency repair scenarios. For regular maintenance at fixed sites, the open-type configuration offers better flexibility in site deployment. |
| Safety Protection Functions: |
The operation of an oil filtration machine involves multiple parameters such as heating, vacuum, and pressure. Safety protection features directly affect equipment lifespan and operator safety. The following protective measures should be carefully examined: |
| Overpressure protection: |
Automatic shutdown when the oil outlet pressure exceeds the set value of 0.5 MPa to prevent pipeline rupture. |
| Oil injection protection: |
A high-level switch in conjunction with a time relay immediately alarms and shuts down when the liquid level in the vacuum separation chamber is detected to be too high, preventing oil from entering the vacuum pump. |
| Heater anti-dry-burn protection: |
Ensures the heater only operates when the oil is flowing normally, preventing the heating element from burning out. |
Other key configurations:
| Heating system | Constant temperature control, maintaining an operating oil temperature of 30–70℃ to ensure dehydration efficiency while preventing oil overheating and aging. The total power is 66KW, with a heating power of 60KW, ensuring sufficient temperature rise capacity. |
| Filtration accuracy | The precision filter uses a 1μm filter element, effectively intercepting fine particulate impurities and meeting the cleanliness requirement of ≤NAS 12. |
| Condensation system | A shell-and-tube condenser, in conjunction with an axial flow fan, condenses and recovers water vapor extracted by the vacuum pump, protecting the quality of the vacuum pump oil. |
| Inlet and outlet oil pipe diameter | Inlet and outlet oil pipe diameter: Both inlet and outlet oil pipes are 32mm in diameter, facilitating on-site connection and pipeline selection. |
| Head | The equipment head is ≤30m, suitable for the oil transportation needs of high-level transformers. |
| Post-treatment oil specifications | Transformer oil treated by a two-stage vacuum oil filtration system should meet the following key indicators: Oil breakdown voltage: ≥70KV Residual water content: ≤10 ppm Residual gas content: ≤0.3% Acetylene content: 0 Filtration accuracy: 1μm |
Choosing a suitable transformer oil purification system can ensure that the processed oil fully meets the requirements of international standards such as IEC 60422. More importantly, regular and high-quality oil filtration maintenance can significantly extend the service life of transformer oil, reduce oil change costs and equipment failure risks, thereby reducing the total long-term operation and maintenance costs.
If you are selecting a suitable oil filtration solution for your substation equipment, please contact us for detailed technical information and customized configuration recommendations. Our professional team will provide the most suitable model based on your actual operating conditions and oil specifications.
