For the design of insulated cylindrical cascaded test transformer

it is very important to accurately calculate and improve the voltage distribution between each stage.This study calculated the internal and external capacitance of a 2 250 kV insulated cylindrical cascaded test transformer according to its winding construction and external dimension by a finite element software

and simplified the external capacitance as an interstage capacitance.An equivalent circuit for calculating voltage distribution of the transformer was built via distributing the load capacitance to each stage

and a simulation was conducted with ATP-EMTP to achieve the steady voltage distribution of the transformer.Changing the turns of the cumulative windings of the lower and middle stages could make the uneven coefficient of voltage output at each stage of the transformer meet requirement.By changing number of turns of windings

the voltage distributions of the transformer were actually measured and the results were satisfactory.