ABSTRACT
Load loss is major energy consumption by a transformer, a main heating source and generally a guaranteed quantity. A well-designed unit has less load loss and local overheating with the same power rating. To understand the mechanism of load loss, the calculation method of winding I 2 R loss and winding eddy current loss are presented to show influential factors on these losses. The practical methods to reduce the eddy current loss are introduced. Circulating current loss in winding as part of load loss and preventive methods such as transpositions are discussed and accompanied with examples. An example of transposition scheme of multi-strand helical winding is given. The stray loss in metallic structural parts of tie-plate, clamping plate and tank wall are discussed individually for the concerns of local overheating, and mitigation methods are offered. An empirical calculation method of stray losses based on tests is presented, and its calculated results are compared to test ones of real units; it shows the method is conservative in most cases with some exceptions. Finally, applications of tank shunts are given for the sake of tank wall loss and temperature reductions.
