Bushing and manufacturing method therefor

A transformer, comprising:

• a bushing having:
• a conductive tube fixedly connected to a bottom connecting assembly and a top connecting assembly;
• and
• a central tube fixedly connected to the bottom connecting assembly and the top connecting assembly, wherein the central tube comprises a hollow tube that is located inside the conductive tube, and wherein the central tube is subjected to a compressive force in an extending direction of the central tube, such that the conductive tube is subjected to a tensile force in an extending direction of the conductive tube,
• wherein the central tube and the conductive tube are pre-stressed to maintain engagement with each other under axial loading without applying axial force beyond the top and bottom connecting assemblies.

A bushing, comprising:

• a bottom connecting assembly;
• a top connecting assembly;
• an electrically conductive tube connected to the bottom connecting assembly and the top connecting assembly;
• a central tube connected to the bottom connecting assembly and the top connecting assembly, wherein the central tube comprises a hollow tube that is located inside the electrically conductive tube, and wherein the central tube is subjected to a compressive force in a first direction by the bottom connecting assembly and the top connecting assembly, and the electrically conductive tube is subjected to a tensile force in the first direction by the bottom connecting assembly and the top connecting assembly,
• wherein the central tube and the conductive tube are pre-stressed to maintain engagement with each other under axial loading without applying axial force beyond the top and bottom connecting assemblies.