What are the rules for measuring insulation resistance of transformers?
The absorption ratio is not specified, but should be considered in the comprehensive review of the measurement results. Usually no less than 1.3.
The insulation value of the transformer shall not be less than 1M ohms per kilovolt during use, and R6O shall be no less than 50% of the previous measurement.
After the transformer is stopped and put into operation, the 1000 - 2500V shake meter is used to measure the insulation resistance and absorption ratio of the coil. Measurements shall be made at the same temperature as possible at the same temperature with the same shaking table as the voltage level. The measured values, the temperature of the oil and the ambient temperature shall be recorded in the insulation record book of the transformer.
