An Improved Model for Calculating the Magnetic Field of the Scattering of a Power Transformer Under the Action of Quasi-Constant Currents

Abstract

A logically simple and quick way of calculating the instantaneous values of the magnetic field in the transformer volume when quasi-constant currents flow in the windings is suggested. To reduce the calculation time, the conductors of windings having a rectangular cross section are replaced by a set of identical circular conductors, which also fill the cross section. It allows you to use analytical expressions. From the values of the components of the magnetic induction vector at the nodes of the uniform grid the matrices are formed for each winding calculated at a single current. In calculating the instantaneous distributions of the magnetic field, the matrices are multiplied by the instantaneous currents in these windings and are summed. The calculations of the distribution of the magnetic field and the Ampere forces in a power transformer of the type TDC - 400000/220 are performed. The calculation results are presented for a quasi-constant current of a 100 A value in high-voltage winding and for its absence. It is shown that under quasi-constant current the pattern of the magnetic field distribution substantially changes and a significant increase in Ampere forces occurs. The calculation model allows you to overcome the difficulties associated with the temporary resources of the computer, and conduct a detailed study of the distribution of the stray magnetic field in the windings.