The dielectric strength test of transformer oil can effectively evaluate the insulation performance of the oil and provide important guarantee for the safe operation of the transformer.
test method: Use the dielectric strength tester
Steps how to do the oil dielectric strength test:
Clean the electrodes and make sure they are spaced according to standards (usually 2.5 mm).
Pour the oil sample into the test cup to ensure that the electrode is completely immersed in the oil.
Increase the voltage at a constant rate until the oil sample breaks down.
The breakdown voltage value is recorded, and the average value is usually measured several times.
Standards: The test should comply with the relevant international or national standards, such as IEC 60156 or ASTM D877.
Influencing factor for the oil dielectric strength
Moisture: Water in the oil significantly reduces the dielectric strength.
Impurities: Impurities such as solid particles or fibers can form conductive channels, leading to breakdown.
Temperature: Too high or too low oil temperature will affect the test results.
Aging: The aging of the oil will reduce its insulation performance.
Result analysis of oil dielectric strength test
The higher the dielectric strength value, the better the insulation performance of the oil.
If the test results are below standard values, the oil may need to be filtered, dried, or replaced.
Matters needing attention
The test environment should be kept clean to avoid external contamination.
The oil sample should be thoroughly stirred before testing to ensure uniformity.
Test results should be combined with other oil quality indicators (such as moisture content, acid value, etc.) to make a comprehensive judgment.