Dielectric response methods

as a new way to diagnose oil-paper insulation of transformer

have caught much attention recently and been developed from the laboratory studies to the field measurements.The equivalent circuit of the transformer oil-paper insulation system could be represented by extended Debye model

a 50 kV·A transformer was tested by time-domain response measurements in the paper

and the test results were fitted by least squares method

and value of n of extended Debye model was determined by the relative error between measured and fitted values

and electrical insulation parameters were calculated and compared with measured values.Results showed that the time domain response method could effectively assess the moisture content and the insulation condition of transformer oil-paper insulation.