Model of Distribution Transformers Winding for Lightning

This paper presents a mathematical model for distribution transformers winding to simulate its lightning impulse behavior. The aim is to investigate the real source of some signals present in the current wave of lightning impulse test. These signals are generally attached to the testing system and not to the testing transformer. This kind of interpretation can consider approved a failed transformer. The procedure takes into account the comparison between lightning impulse tests on actual transformers and their simulation results. The main contribution of this paper regarding previous publications [1]-[2] is concerning the current wave of chopped impulses. The idea is to use the chopped waves to confirm the existence of small failures on tested transformers that present some of noises in the current wave of full impulses.