Quality assessment operating oil power transformers 35–110 kV

Analyzed is the existing approach to evaluation of technical conditions of 35–110 kV power transformers relying on the results of physicochemical analysis of insulating oils, the drawbacks of such approach pointed out.

Proposed is a system for more adequate evaluation of operational transformer oil parameters and measures for its serviceability recovery and prolongation.

One has demonstrated the necessity: to introduce a new indicator of operational transformer oils quality – “oxidation stability”; revise the threshold values of the acidity index, of content of water-soluble acids and alkali, oil dielectric loss angle tangent, content of agidol-1 (ionol) antioxidant additive in oils filled into 35 - 110 kV power transformers without dedicated oil protections; revise the scope of indicators to be measured for scheduled physicochemical analysis of oil samples established for 35–110 kV power transformers without dedicated oil protections.