Efficiency analysis of a three-phase power transformer for industry applications operated under different load conditions

Nowadays many industries experience a problem with the efficiency of transformers. Metal, chemical, cement, concrete, automobile, mining and other industries struggle to increase the efficiency of energy use. One of the methods is applying highly efficient electric equipment. Three-phase power transformers play significant role for the listed industrial sectors in terms of energy saving. This paper represents efficiency analysis of the common type of a three-phase power transformer which is widely used in industry to change values of three-phase voltage and current. The technical parameters determined by conducting a short-circuit and open-circuit tests on the transformer. The parameters that were obtained were used to draw up an equivalent circuit. From this circuit the efficiency of the transformer is calculated at different rated loads. The practical tests can be performed on any three-phase transformer in the industry. The test presented in this paper was performed in a heavy current laboratory. The conclusions about energy losses when the transformer operates out of rated load are presented.