Analysis of star-star-delta_utilized transformer under balanced and unbalanced load conditions

For decades research has been going on to resolve the power quality issues. The usage of non-linear loads is contributing much harmonic content in the distribution system. In the conventional distribution transformer of delta-star configuration, this injected harmonic power is trapped in delta winding and is wasted as heat. This wasted power or drainage power is a threat to the transformer itself. This paper presents the recovery of drainage power using star-star-delta_utilized distribution transformer under varying load conditions in the secondary. A study on primary and secondary side THD, input and output power factor, current harmonics, harmonic power and efficiency is carried out for balanced and unbalanced load conditions. The simulations are carried out in MATLAB Simulink and the results are verified by experimenting on the hardware set up.