Change-preventing transformer

A change-preventing transformer which is simple in structure, can be detected in a visualized and effective manner, and guarantees safety electric power production. The transformer comprises a transformer body, a top cover and a nameplate. The top cover is connected to the top surface of the transformer body through pairs of bolts and nuts. The nameplate is detachably connected to the side of the transformer body. The change-preventing transformer further comprises a change-preventing mechanism. The change-preventing mechanism comprises first seals and mounting holes in the nuts, wherein the first seals are disposed in the mounting holes. The change-preventing transformer has the advantages that two diagonal nuts on the top cover are drilled, the first seals are added to the drilled mounting holes, so that a user cannot change the top cover of the transformer optionally; a second seal is added to the nameplate, so that the user cannot change the nameplate optionally; private transformer change is reduced effe