Determination of the saturated inductance of transformers by analytical formulae, comparison with an electromagnetic field calculation approach and validation by on-site tests.

This document describes the determination of the saturated inductance of a transformer, which is the slope of the saturation curve Phi(I) under highly saturated conditions. This parameter, which has a strong impact on the overvoltages when energizing a transformer, has been determined from analytic formulae for a shell-type transformer. Comparisons with the values derived from an electromagnetic 3D calculation and on-site tests are also given in this paper.