Firstly, the insulation resistance and absorption ratio of the transformer winding are measured with a high voltage Megohm, and the DC resistance of the winding is measured by a DC resistance rapid tester. The voltage ratio of all the connections of the winding is measured with a fully automatic variable ratio test instrument. The load characteristics tester is used to measure the no-load current and no-load loss, short circuit impedance and load loss, while the on-load switch tester is used to measure the transition resistance, switching time and other parameters of the on-load switches. Then, The dielectric strength of the transformer oil is measured by a automatic insulating oil dielectric strength tester. Loss of winding and capacitive catheter is measured by a automatic anti-interference of dielectric loss in different frequency tester. Finally, the chromatographic analyzer is used to analyze the gas chromatography in transformer oil.
Other tests can be further implement only when the parameters above are qualified through comprehensive analysis. We can use DC high-voltage generator or AC and DC high-voltage test transformer to conduct DC leaking test for insulation ducts and winding of the transformer. In the end, the AC voltage tester transformer can be used to carry out AC voltage test to the transformer. At this point, the testing project of the power transformer is completed.