Why needs Transformer Oil Filtration Equipment?

Transformer Oil Function:
Transformer oil's primary functions are to insulate and cool a transformer. It must therefore have high dielectric strength, thermal conductivity, and chemical stability, and must keep these properties when held at high temperatures for extended periods. Typical specifications are: flash point 140 °C or greater, pour point −40 °C or lower, dielectric breakdown voltage 28 kV (RMS) or greater.

To improve cooling of large power transformers, the oil-filled tank may have external radiators through which the oil circulates by natural convection. Power transformers with capacities of thousands of kVA may also have cooling fans, oil pumps, and even oil-to-water heat exchangers.

Power transformers undergo prolonged drying processes, using electrical self-heating, the application of a vacuum, or both to ensure that the transformer is completely free of water vapor before the insulating oil is introduced. This helps prevent corona formation and subsequent electrical breakdown under load.

Transformer Oil Testing and Oil Treatment 

Transformer oils are subject to electrical and mechanical stresses while a transformer is in operation. In addition there is contamination caused by chemical interactions with windings and other solid insulation, catalyzed by high operating temperature. The original chemical properties of transformer oil change gradually, rendering it ineffective for its intended purpose after many years. Oil in large transformers and electrical apparatus is periodically tested for its electrical and chemical properties, to make sure it is suitable for further use. Sometimes oil condition can be improved by filtration and treatment.

Onsite testing : 
Oil Breakdown Volatge Testing is recommended.
To determine the insulating property of the dielectric oil, an oil sample is taken from the device under test, and its breakdown voltage is measured on-site according to the following test sequence:

In the vessel, two standard-compliant test electrodes with a typical clearance of 2.5 mm are surrounded by the insulating oil.
During the test, a test voltage is applied to the electrodes. The test voltage is continuously increased up to the breakdown voltage with a constant slew rate of e.g. 2 kV/s.
Breakdown occurs in an electric arc, leading to a collapse of the test voltage.

Immediately after ignition of the arc, the test voltage is switched off automatically.
Ultra fast switch off is crucial, as the energy that is brought into the oil and is burning it during the breakdown, must be limited to keep the additional pollution by carbonisation as low as possible.
The root mean square value of the test voltage is measured at the very instant of the breakdown and is reported as the breakdown voltage.
After the test is completed, the insulating oil is stirred automatically and the test sequence is performed repeatedly.
The resulting breakdown voltage is calculated as mean value of the individual measurements.

HOPU Filtration Plant Manufacturer Co.,ltd is a professional manufacturer of transformer oil purifier and oil tester in Chongqing,China, The whole technical support team is very experience in transformer oil treatment work.
Your inquiry is warmly welcomed !