Abstract: This paper is based on the ferromagnetic resonance test platform of the medium-voltage distribution system in a nuclear power plant, and the functions and resonance effectiveness of the new microcomputer resonance elimination device are systematically verified under various working conditions, such as diesel engine emergency, plant transformer operation, auxiliary transformer operation, and intermittent grounding. Test results show that the identification and elimination success rates of the new microcomputer resonance elimination device are both up to 100% in 2500 resonance elimination tests and it still maintains high reliability under extreme working conditions. The parallel connection of the elimination resistor with the device can significantly improve the elimination effect. In addition, the device has a able temperature rise under the continuous operation condition and does not damage the equipment. The research results provide an important technical support for the safe and stable operation of the medium-voltage distribution in nuclear power systems.