ANSI=IEEE defines a transformer as a static electrical device, involving no continuously moving parts,
used in electric power systems to transfer power between circuits through the use of electromagnetic
induction. The term power transformer is used to refer to those transformers used between the generator
and the distribution circuits, and these are usually rated at 500 kVA and above. Power systems typically
consist of a large number of generation locations, distribution points, and interconnections within the
system or with nearby systems, such as a neighboring utility. The complexity of the system leads to a
variety of transmission and distribution voltages. Power transformers must be used at each of these
points where there is a transition between voltage levels.