This series of transformers is a pillar structure, using epoxy resin fully enclosed casting, the transformer is made of three independent transformer windings through Y-Y wiring, the neutral point is connected in series with one end of the primary coil of the fourth transformer, and the other terminal is grounded during operation to realize the voltage measurement and protection of the three-phase voltage system. This type of transformer comes with a high-voltage fuse on the primary side, which can effectively protect the transformer body in the event of a system failure, saving the size of installation space. It is small in size, light in weight, and suitable for installation in any position and direction. This transformer has its own harmonic elimination function, and no additional harmonic elimination device is required.