Modeling and insulation design methodology in power transformer under fast transients

Abstract

In this paper a practical modeling and design methodology for evaluating the insulation system in power transformers under fast transient voltages is proposed. The presented method is based on RLCG lumped frequency-dependent parameters linked to a 2D axisymmetrical electric field finite element model. The methodology was applied to a real EFACEC power transformer. A comparison between computed and permissible electric field values with the safety factors for evaluation dielectric strength of each dielectric material inside of power transformer was carried out.