The insulation condition of current transformer can be reflected sensitively by the high-voltage dielectric loss.When the tanδ exceeds standard or other insulation defect is suspected in the preventive test

it is necessary to measure the tanδ under high-voltage

and pay attention to the capacitance variation.The series-compensated method is an effective method to measure high-voltage dielectric loss in field test.Attention should be paid to the influence of the high-voltage leading wire and the electric field interference on the field test.Moreover

comprehensive analysis of measurement results should be conducted.