ABSTRACT
Fully understanding tests that a transformer goes through certainly helps for better design as well as better manufacturing quality. Each routine and type of tests, such as preliminary tests, no-load loss and excitation current, lightning impulse and switching impulse, applied voltage, induced voltage and partial discharge, load loss and impedances, temperature rises and audible sound level, are introduced on their setups, measurement method and criteria, as well as issues and problems incurred in the tests and suggested measures to solution, or guide for investigating on failures based on years of testing experiences and knowledge. The short-circuit test is also described. Besides the tests requested as minimum by standards to qualify a transformer for service, the popular tests conducted in manufacturers and field services such as oil and SFRA are introduced on their purposes and application ways. A brief discussion on the dielectric frequency response test is given.
