Analysis of A Few Continuous Ferromagnetic Resonance PT Faults in Power Plants and Improvement Measures of Harmonic-free Suppression Technology

Abstract

Many vicious faults of burning PT and high-voltage fuse caused by ferroresonance occurred in power plants. Microcomputer harmonic elimination device and silicon carbide harmonic elimination device did not work; particularly silicon carbide harmonic elimination devices burnt together with PT. This paper, enumerating the excitation conditions of PT ferromagnetic resonance, analyzes the circuit characteristics of PT circuit ferromagnetic resonance in the power plant and the power frequency voltage characteristics of the sound phase when the single-phase grounding fault occurs in the neutral point ungrounded system. The defects of the existing harmonic elimination device are summarized, and the technical improvement measures are proposed to add the current-sensitive intelligent harmonic elimination device. Practice shows that this kind of harmonic elimination device can effectively avoid PT bursts and fuse-fusing faults caused by the resonance of the intermittent grounding of the system.