Evaluation of Harmonics & Its Effect on Transformer Load Loss

The increased use of non linear modern loads that use high frequency switching generate harmonics in distribution system. The existence of high level harmonics causes several undesirable effects such as transformer overheating, increase of running losses, increase in loading profile of transformer, nuisance tripping of protection devices and loss of life of transformer. In this paper evaluation of the harmonics spectrum level of distribution transformer feeding combination of non linear and linear loads and its effect on the capacity reduction and power factor. The harmonics spectrum data obtained using power quality analyzer (PQA) is compared against IEEE standard and possible solution is recommended. Based on harmonics spectrum data, increase in total load current and power loss are respectively 14.5 % and 7.2% Keywords: Harmonics, Distribution transformer, Power loss