Features of Measuring the Windings Resistance of Power Transformers to Direct Current

Abstract

Analysis is provided of the processes of change of magnetic induction in the magnetic core of power transformers during measurements of windings resistance to direct current. A methodology was developed to calculate the time needed for exit to measurement mode. It is shown that this time is proportional to the ratio of the rated winding voltage to the voltage from the power supply of the measuring device. It is noted also that the time needed for exit to the mode of measurement of windings resistance to direct current on the side cores is less than the analogous time for the winding on the central core. The methodology has been confirmed with practical measurements on the power transformers of the Donbass electrical power system.