Any power transformer can have a set up or step-down structure, but there is a difference in the structure between the three winding transformer and the two winding transformer.
In set up transformers, the low voltage winding is in the middle, that is an order of middle, medium and high. This is because usually its power supply is a generator (probably 6-10kv) or a transformer up one level (probably 10kV or 35kV). There are two sets of transformer output, one group of high pressure (possibly 110, 220 kV, etc.), and the other group of medium pressure (possibly 35, 110 kV, etc.). The winding arrangement at that time is usually: the inner medium pressure (close to the core), the middle low pressure, and the outside high pressure.
The reason for distribution in that way is that the input end is low and the output end is high or middle. With low in the middle, the low-high, and low- medium distance is the shortest, thus the distance of magnetic energy propagation is reduced, that is, reducing the loss of magnetic energy in space. With the reduced leakage resistance of low-high and low-middle, the percentage of short circuit voltage between low-high and low-medium is reduced, and the reactance is reduced so that the energy conversion efficiency of transformer is improved.