Regular maintenance of power transformers

① Oil sample analysis - voltage resistance, impurities and other performance indicators are tested every three years. Transformers that operate at full load or overload for a long time can shorten the cycle.
② The insulation resistance of high and low voltage should not be lower than 70% of the original factory value (10M Ω). The DC resistance of the winding should not differ by more than 2% from the average value of the three phases at the same temperature, and should not exceed 2% compared to the results of the previous measurement.
③ The grounding resistance value of the transformer should be measured every two years.
④ The cycle of power outage cleaning and inspection is determined based on the surrounding environment and load situation, generally once every six months to once a year;
The main content includes__ Remove defects found during inspections, clean the porcelain casing shell, replace broken or aged rubber pads, inspect and tighten connection points, replenish oil shortage, and inspect and replace respirator silicone.