ABSTRACT
Transformer losses are broadly classified as no-load or core losses and load losses. No-load losses occur when the transformer is energized with its rated voltage at one set of terminals, but the other sets of terminals are open circuited so that no through current or load current flows. Load losses occur when the output is connected to a load so that current flows through the transformer from input to output terminals. Load losses are in turn broadly classified as I2R losses due to Joule heating produced by current flow in the coils and as stray losses due to the stray flux as the stray flux encounters metal objects such as tank walls, clamps or bracing structures, and the coils themselves. The eddy current losses can be obtained from finite element calculations, especially 3D ones that can model the rectangular tank and leakage flux from all three phases simultaneously. Shunts are frequently used to reduce losses or to eliminate hot spots.
