Recently, the dry-type transformer jacket with impregnated fiber insulation has been widely used in grid renovation projects. It offers excellent protection against electric shock and flashover, but it is important to note that this design does present certain issues in actual operation, which can increase the difficulty of maintenance and inspection for distribution equipment.

Oil leakage in protective sheaths is often not detected in time. Once the surface of transformer sheathes becomes dirty due to oil leakage, it's prone to electrical arcs during thunderstorms. These arcs can also damage the sheath surface, potentially causing punctures that go unnoticed. This makes it difficult to locate the fault points in distribution accidents.

Conductive rods in jacketed transformer bushings are prone to breakage that is not easily detected. Due to the insulating effect of the jacket, during multiple defect treatments of distribution transformers, it was found that the broken conductive rods in the jacket are not promptly discovered, which affects normal power supply and directly endangers the safety of the distribution equipment. Additionally, it also poses certain difficulties for maintenance.

Transformer bushing jacket conductive rods' connection points with wires or equipment clamps are not easily detected for discharge or sparking. Due to the non-visibility of the jacket's insulation, timely discovery of discharge or sparking at transformer bushing conductive rod connection points cannot be made, which can lead to unstable power supply, equipment failure to start normally, and eventually burning out. This is because timely maintenance cannot be obtained, thereby affecting the safe operation of the distribution transformer.