An Improved Method for Calculating Power Transmission Equipment Loss and Hot Spot Temperature in Distribution Network under Harmonic Disturbance

Distribution transformer is widely used as an important energy transmission equipment. In recent years, with a large number of non-linear loads used in power grid, the impact of harmonic pollution on the power system has become more and more serious. Harmonic disturbance affects the no-load loss, load loss and hot spot temperature of distribution transformer, thus further shortening the service life of transformer. An improved method for calculating loss and hot spot temperature is presented in this paper. Firstly, the influence of harmonics on load loss is analyzed. The load loss calculation model of transformer under different connection groups is established. Secondly, the variation of core loss with harmonic frequency and flux density is analyzed. The load loss calculation model of transformer under different connection groups is established. Finally, the temperature rise calculation model proposed by IEEE C57.110 is revised. Considering the effects of stray loss and no-load loss, a more accurate method for calculating hot spot temperature is proposed.