Transformer oil filteration for moisture extraction

Oil filtration can greatly prolong the life of the transformer: the filtration process includes mainly drying of oil by extracting moisture under heat and vacuum. The process improves the electrical insulation capability of the oil and thusly protects the solid insulation (cellulose: paper and wood) from the destructive process introduced when moisture meets cellulose – a process called depolimerization.

A common test of moisture is the Breakdown-Voltage tests (BDV test). A good oil insulation is above 60kV under IEC standard 60156 and higher.

In addition, oil circulation has the following advantages:

  • Reduced acidity
  • Filteration of micro-particles: the oil is filtered through three filters: a magnetic filter, a 20 micron filter and a 5 micron filter.
  • Addition of inhibitor additive to the oil is possible after filteration.

For critical transformers, that cannot be taken off-line, we are capable of filtering the oil while the transformer is energized.

Our mobile oil filtration machines are capable of filtering up to 6,000 L/min and are one of the largest mobile machines in the country.

סינון שמן לשנאי 15MVA ולשנאי גיבוי קריטי
Oil filtration for a 15MVA transformer at right, and a special UPS transformer at left