6.2.Measure the DC resistance of the winding with the bushing and it should conform to the following requirement: 1)The measurement should be conducted in positions of all taps; 2)As for the transformer of over 1600kVA, the difference between windings of all phases should be no more than 2%; with regard to the winding led out by the non-neutral point, the difference between lines should be no more than 1%; 3)Comparing with the manufacturer measured value of products in the same temperature, the corresponding change should be no more than 2%.