Abstract:In order to shorten the testing time of DC resistance,the magnetic circuit method is usually used in the test of low-voltage winding DC resistance of large transformer.The influence on remaining magnetic in the core of different wiring mode based on magnetic circuit method is analysed,and a more ideal wiring model is selected.The wiring model optimizes the direction of charging current and voltage excitation during the test,so as to make the magnetic flux direction in the core as consistent as possible with the remaining magnetic after testing one-phase winding,and make reasonable use of the remaining magnetic in the core to assist magnetic to the trial windings.A 500 kV transformer substation's main transformer is used as an example to compare the test results of all wiring modes,the results prove that the selected wiring method can shorten the testing time to a certain extent,and improve the working efficiency.