Rise-of-temperature method for building factor distribution in 1-phase model transformer core interior considering high DC bias

Abstract

Loss distributions of transformer cores are affected by z-flux effects if considered for the core surface. Here we propose the application of a thermal sensor which is inserted to the core interior through one of 16 channels of 2 mm width. Measurements were made on a 1-phase core assembled from laser-scribed SiFe. Throughout the core, the local building factor BF proved to increase towards the periphery which can be interpreted by interactions of highest anisotropy and non-linearity. Additional DC superposition yields non-uniform increases of BF at different core positions. Local losses tend to become more balanced -measurement locations with a priori high BF experience lower percentage increases, being more robust with respect to DC components.

Investigation on the magnetic bias current and electromagnetic force of power transformer in multi-layer soil area

“…Hence, increasing noise and vibration, distortion of the excitation current, increasing copper loss and iron loss, overheat will arise in the transformers due to the magnetic bias current (MBC), which is harmful to the safety of power transformers and power system [1][2][3][4][5]. To accomplish the long distance power transmission more and more UHVDC transmission lines will be built in China.…”