Influence of harmonic on loss and temperature rise of mine-used dry-type transformer

In order to accurately analyze influence of harmonic on loss and temperature rise of transformer, a two-dimensional model of dry-type transformer was established firstly, and leakage magnetic field and harmonic loss in the dry-type transformer were simulated. Consequently, distributions of axial and longitudinal leakage magnetic in the transformer, as well as relationship between harmonic loss and harmonic order, harmonic ratio and distortion factor of harmonic current were derived. Then fluid-structure interaction analysis of the two-dimensional temperature field and airflow field of the dry-type transformer was conducted using finite element software Fluent, and the relationships between the temperature rise and harmonic order, as well as distortion factor of harmonic current were gained. Simulation results show that the harmonic copper loss is proportional to square of harmonic current ratio, and it is also approximately proportional to square of harmonic order when the content of harmonic current ratio is certain; the harmonic iron loss is proportional to square of harmonic voltage ratio, but it decreases and gradually tends to flatten out with harmonic order increases when the harmonic voltage ratio is certain.