1. In case of inter turn and inter phase short circuit at the low-voltage side of the voltage transformer, the low-voltage fuse has not been fused yet. Due to the rapid increase of excitation current, the fuse of the high-voltage fuse tube will fuse or burn out the transformer.
2. When the 10kV outgoing line is single-phase grounded, the non fault phase to ground voltage at the primary side of the voltage transformer is 3 times of the normal voltage value. The iron core of the voltage transformer soon saturates, and the exciting current increases sharply, causing the fuse to fuse.
3. The components with capacitive and inductive parameters in the power network, especially the ferromagnetic inductance components with iron core, cause ferromagnetic resonance when the parameter combination is unfavorable.
4. The zero sequence current flowing through the primary winding of the voltage transformer increases (relative to the system where the grounding current exceeds the standard). When the zero sequence transformer operates for a long time, the thermal effect generated by the zero sequence transformer will damage and crack the insulation of the voltage transformer;
5. There is nonlinear oscillation (arc grounding overvoltage) in the system, which greatly aggravates the damage process of voltage transformers in the system;
6. The heat dissipation condition of voltage transformer is poor.
