Further Improvements in Topological Transformer Model Covering Core Saturation

This paper is devoted to improvements of the low-frequency topological model a three-legged stacked-core transformer. It shown that B-H hysteresis loops employed in transformer and ψ– i curves measured at terminals are quite different shape. A distinction made between modeling moderate deep saturations, separated conditionally by level technical saturation (near 2 Tesla) typical for grain-oriented steels. In former case, addition magnetic coupling phase windings through core, an important part played air gaps core joints. found effective gap length depends on instantaneous flux this dependence proposed implement variable inductances. regardless depth, role belongs distribution zero-sequence path all phases. accurate replications special purpose test, modeled results close agreement with positive- zero sequence data 50 kVA transformer, as well inrush currents.