The transformer casing should be inspected before installation.

(1) Whether there are cracks on the surface of the porcelain sleeve.

(2) Whether the neck of the casing flange and the inner wall of the pressure equalizing ball are cleaned.

(3) Whether the casing has passed the test.

(4) Whether the oil level indication of the oil-filled casing is normal and whether there is oil leakage.

The transformer bushing is an insulating bushing that leads the high and low voltage leads inside the transformer to the outside of the fuel tank. It is not only insulated as a lead to the ground, but also acts as a fixed lead. The transformer bushing is one of the current-carrying components of the transformer. Long-term through the load current, through the short-circuit current when a short circuit occurs outside the transformer. Therefore, the following requirements are imposed on the transformer bushing:

(1) Must have specified electrical strength and sufficient mechanical strength.

(2) It must have good thermal stability and can withstand transient overheating during short circuit.

(3) Small size, small quality, good sealing performance, strong versatility and easy maintenance.