Abstract: In vitrification plant melter research project, its power supply system through the use of single-phase thyristor power regulator to adjust the voltage on the primary side of the transformer and transformer gear switching, to achieve the current value of the heating circuit is set, and through the transformer on the secondary side of the bus transformer to achieve the current and voltage feedback. During the operation of the furnace, it was found that the temperature of the NU01 heating circuit of the furnace was abnormal, through the investigation and analysis of the problem, an optimized method of measuring the current on the secondary side of the transformer was given and verified in the test, and the test results met the operational requirements of the furnace.