JLD-72.5 type voltage transformers are oil immersed combined current voltage transformer. The part of VT is imitation shape tank structure. The core was used cold-rolled silicon steel strip to folded. The high voltage coil adopts sectional winding method. The part of CT is inverted structure. The primary conductor passes through the center of the secondary winding and has high measurement accuracy. The secondary windings are protected within the aluminum shield. The rods part of the two body are insulated with capacitive screen structure. They are inside the porcelain bushing and reduce the amount of oil used in the transformer. We select corrugated metal expander as oil temperature variation compensator and can inspect the oil level through window. Outline dimensions drawing and structure shown in Figure 1.