Abstract: Potential transformer (TV) is an important equipment for measurement and protection in distribution network. The high voltage side of TV is usually equipped with fuse for protection, but abnormal fuse blown often occurs, affecting the safety of power system. In order to solve this problem, this paper analyses the causes of the fault from the circuit principle, and verifies the theoretical analysis using RTDS simulation platform, and obtains the voltage-current characteristics under abnormal conditions such as ferromagnetic resonance and under-frequency non-linear oscillation. An improved method for resonance elimination is put forward and analyzed, and proves valid. In view of its limitations, it is proposed to combine the proposed method with the high saturation point TV method, which can better suppress over-voltage and over-current. Finally, on this basis, several existing countermeasures for fuse blown are verified and compared, and the feasibility of various schemes is summarized.